Question 1

What are the most common causes of hydraulic system failure?

Accepted Answer

There are many reasons that could cause a hydraulic system to break down, many of which are preventable if carefully monitored. Here we take a look at some of the signs and symptoms of hydraulic failure.

Fluid contamination

One of the main reasons hydraulic systems fail is due to fluid contamination. Whatever the type of fluid being used, if it becomes contaminated with any dust, dirt, or moisture, this can reduce the pumps ability to control system pressures. This in turn, can lead to overheating or a build-up in the system that causes the parts to seize and fail.

Always ensure that the different components and fluids are clean and fit for purpose before use, to prevent failure from occurring.

Poor or irregular maintenance

Servicing is vital to keep a system running smoothly. It is important to ensure that the system’s oil and filters are changed appropriately. Poor or irregular maintenance could cause the system to become contaminated, increasing wear on the pump and associated equipment.

The suction hose between the tank and pump also needs to be in good condition and replaced if any sign of wear.

It is good practice to inspect a hydraulic unit regularly, checking the oil levels, cleaning up any spillages and reporting any defects immediately.

Misuse and human error

It is imperative that proper instruction and training is given to anyone that is using an application operated by a hydraulic system. Faulty installation, using incompatible parts or improper usage are all major factors that can cause failure.

Environmental & operating factors

Temperature and working conditions all have an impact on the system.

The power unit needs be housed or operated in a well-ventilated area, so that the oil coolers are kept free from dust and contamination.

Is the application operating in high temperatures? If so, close attention will need to be given to the type of fluid used and specialist seals will need to be installed, in all applications. Always avoid using mineral based oils in high temperature applications, these are refined from crude oil and have a flash point, which means that they will ignite at a certain temperature.

If the application is operating in cold environments, a tank heater may need to be installed, in order to maintain the fluid viscosity. Hydraulic fluid that is too thick or too thin can cause damage to the system.

Aggressive working conditions can also put strain on a system, leaving it vulnerable to failure. External shocks and vibration can cause surging and cavitation between the tank and the inlet of the pump. This can be avoided by properly mounting the power unit on special anti-vibration units.

The hydraulic tank also needs to be mounted higher than the pump and kept as close together as possible.

No matter what the application, hydraulic system failure is inevitable at some point. However, issues can be avoided if you ensure that you regularly follow all maintenance procedures and make certain that the appropriate components are installed or replaced correctly. If you are unsure of anything, don’t be afraid to call on your industry peers or hydraulic professionals for their help and advice.

Question 2

How Do Hydraulic Seals Work?

Accepted Answer

Seals are essential to fluid power engineering, as they prevent a fluid or gas from passing between the different components of a hydraulic cylinder.

Dynamic (used when parts are in motion) or static (fixed application), different types of seals, each have their own role to play, in ensuring a cylinder runs as smoothly as possible.

Our quick guide below shows the main types of seals that you would find in a cylinder and describes how they operate.

Wiper Seals

Wiper seals or Scraper seals are designed in a way to keep external contaminants out of a hydraulic system, by cleaning the rod in the cylinder on each cycle.

Rod Seals

Also known as Gland seals, Headbush or Neck Seals, Rod seals act as a pressure barrier to maintain and regulate the operating fluid in a cylinder. They can seal the pressure from one side (single-acting) or from both sides (double-acting). Rod seals are key in preventing corrosion.

Static Seals

These are used to create a seal between fixed components. The full range of static seals include o-rings, back-up rings, flange seals, bonded washers and OP seals.

Piston Seals

Piston seals are important for controlling the motion of a cylinder. It creates a barrier for dynamic pressure between the piston and the cylinder, preventing fluid from passing the piston and allowing the cylinder to extend and retract.

Guide Rings

Guide rings also known as bearing rings, stop metal-to-metal contact between two dynamic cylinder components. This is crucial in the prevention of damage to the two moving surfaces.

The right seal for the job

When selecting the best seals for your hydraulic ram, both at OEM or repair stage, it’s important to consider the parameters of the application and the operating conditions.

High pressure, medium used, extreme temperatures, aggressive chemicals, working environment and legislation standards will all have an impact on the chosen material of seal.

Over time however, it is expected that hydraulic seals will eventually need replacing, this can be down to general wear and tear, improper installation or exposure to extreme elements.

Most replacement seals, for most applications can be found off the shelf and seal kits for well known applications can be picked up easily.

If you require any further advice regarding seals and their applications, the team of experts at FPE Seals can help you source what you need.

Can’t find what you’re looking for? We can also custom-manufacture a full range of seals, in a full range of materials to meet your exact requirements.

Contact us today

Question 3

What is a Hydraulic Ram and How Does It Work?

Accepted Answer

A hydraulic ram is a cylinder with a movable rod that can move a mass, or an obstruction as so required.

In principle, a hydraulic ram works by an external fluid being pumped into either side of a cylinder simultaneously, this creates a high pressure and low-pressure side within the cylinder depending on the load that it is trying to move.

Here we explore some of your commonly asked questions surrounding hydraulic rams, what they’re used for, how hydraulic devices work, and how hydraulic rams work.

How does a hydraulic device work?

Hydraulic devices use fluid that is moved by an external pump driven by a power unit. Hydraulic devices are designed around the principle that liquids are always considered to be incompressible. This means that when a force is applied at one point, the liquid will transfer an equal force at another point.

Most common hydraulic devices work by using a hydraulic pump, a reservoir for fluid storge to the pump. Mechanical energy is converted to hydraulic energy, moving the liquid through a system. Valves are used to regulate the flow of the liquid and control the pressure of the device. A hydraulic cylinder then converts the hydraulic energy back into mechanical energy.

There are a variety of hydraulic devices, including hydraulic rams, but most will use these components in their operation.

How do hydraulic rams work?

Hydraulic rams consist of several components:

• Cylinder,

• Piston,

• Neck Gland,

• Rod,

• Cylinder Ports

• End Caps

The area between the piston and the gland (rod side) is called the Annular side, & the area between the piston & the end cap is called the Full-Bore side.

Pumping fluid into the cylinder port on the Annular side of the cylinder will result in the rod being retracted, giving you a closed centre. Reverse the flow into the opposite port on the Full-Bore side and the piston will then extend the rod out of the cylinder (open centres), at the same time pushing the oil from the Annular side (low pressure) back to tank.

What is a hydraulic ram used for?

Today, hydraulic rams are used all over and have a variety of uses, from heavy plant and mining machinery such as excavators and diggers, agricultural equipment, to food & beverage and packaging machinery, deep sea, marine and automotive applications, to hand tools, fairground amusements and even zoo doors...the list goes on and on.

FPE Seals is a manufacturer and distributor of hydraulic cylinder parts and seal kits for devices including hydraulic rams. Shop online or contact us and find out how our cylinder parts can help improve your hydraulic systems.

Question 4

Seal Failure: Common Causes and Cures

Accepted Answer

In the world of machinery, repair and maintenance is a simple fact of life. So, it should come as no surprise that when it comes to sealing products being used for hydraulic and pneumatic applications, wear and tear is inevitable

Even when you have diligently installed the most robust product, in the best kind of material, certain factors will always lead to seals eventually having to be replaced.

Thankfully in most cases, problems can be identified early, before any serious operational damage can occur, and seals are easily reinstated.

Here we take a look at typical seal failure, the likely causes, and what can be done to rectify the problem.

Hardening

Hardening of the dynamic face has caused glazing and cracks.

Cause: Heat generated by high speed.

Cure: Slow stoke speed or use an alternative seal device.

The whole seal has gone hard and elasticity is lost.

Cause: High fluid temperature, deterioration of fluid or problem with the compatibility of the seal to the fluid.

Cure: Lower the oil temperature, renew fluid or change to a different seal compound.

Wear

The dynamic face of the seal is worn to a glossy mirror-like finish.

Cause: Insufficient lubrication

Cure: Check oil viscosity or use an alternative seal device.

Wear on dynamic lip of seal is egg-shaped.

Cause: Rod or piston bore is not concentric

Cure: Hone to within seal specifications or replace the worn rod or cylinder tube.

Signs of abnormal wear on one side of the dynamic lip.

Cause: Worn bearing or wear ring. Excessive lateral load.

Cure: Replace bearings. Increase bearing area.

Scarring

Cut or dent on the lip.

Cause: Storage on a nail or peg. Improper installation tool

Cure: Store flat in a plastic bag in a closed cardboard box. Installation tools should not have sharp edges.

Scratched on the dynamic side.

Cause: Scars on the rod or bore or foreign material in fluid

Cure: Hone, polish and deburr metal parts or flush the system.

Swelling

Material is soft and misshaped.

Cause: Absorption of fluid. Fluid and seal are incompatible or the there is water in the system.

Cure: Change the seal compound or system fluid. Or flush the system.

Deterioration

Cracks and loss of elasticity. The material easily crumbles.

Cause: High fluid temperature. Exposure to ozone or sunlight.

Cure: Lower oil temperature. Store seals away from sunlight and arc welding area.

Grooving

Axial cuts on the dynamic side.

Cause: Metal chips or other foreign material in system. Imploding air bubbles.

Cure: Flush System. Bleed air from the system.

Extrusion

Extruded material on the dynamic side of heel

Cause: Gap between mating surfaces is too wide, worn bearings or extreme pressure.

Cure: Employ a back ring, replace the bearings or use an alternative seal.

Extruded material on the static side of the seal.

Cause: Uneven support surface or undersized back-up ring.

Cure: Machine surface. Correct back up size.

Fracturing

Chunks of material torn from the dynamic side.

Cause: Excessive back pressure.

Cure: Check relief valves.

Pressure side of seal burned and broken.

Cause: Explosion of residual air at high pressure. ‘Dieseling’

Cure: Bleed air from the system.

Long cracks in the “V” portion of the seal.

Cause: Frequent high pressure shocks or spikes. Low temperature start-up.

Cure: Use alternative style seal. Warm system before applying pressure.

Breaking off of entire dynamic side.

Cause: Deterioration of material and/or fluid.

Cure: Use alternative material or seal. Flush system.

Replacement seals and seals kits, for most applications can be found off the shelf and despatched to you quickly.

If you require any further advice regarding seals and their application, the team of experts at FPE Seals can help you source what you need.

Can’t find what you’re looking for? We can also custom-manufacture a full range of seals, in a full range of materials to meet your exact requirements.

Contact us today

Question 5

Trouble Shooting Common Cylinder Creep

Accepted Answer

Cylinder drift is a common problem that can occur with hydraulic systems of all types.

Tim Bone, FPE Seals Cylinder Parts Manager

This is something that FPE Seals Cylinder Parts Manager Tim Bone knows only too well and is often offering our customer advice on how to troubleshoot the problem. Here he explains more on how you can get to the root cause of your creeping cylinder.

What is causing a hydraulic cylinder to creep faster than expected?

Often the cylinder on a hydraulic application can creep. The popular assumption for this, is that the problem is due to oil passing over a worn piston seal.

However, Tim explains, “Often customers tell me that even when they have resealed the cylinder several times, it still weeps down.

“In many cases, the more likely cause is that the oil is passing across the spoil, rather than the problem being with the seals.

“A simple way to test this, is to lower the load onto the ground so that the cylinder is not under tension, isolate the power source i.e. the hydraulic unit and relax the pressure in the system.

“You can then remove the hose, from the cylinder port that the direction of the rod is moving in (i.e. if the rod is extending, then remove the hose from the annular side, if the rod is retracting then remove it from the bore side). Place a high-pressure ball valve in the line, attaching the hose to the opposite side of the ball valve.

“Make sure that all connecting joints are tight and leak-proof and clean up any spillages.

“Move the lever of the ball valve to open position. Restart the hydraulic power source and operate the valve block (levers), placing load onto the cylinder concerned.

“If the cylinder shows signs of dropping again, move the lever of the ball valve to the closed position.

“If the cylinder stops creeping, this proves that the fault is in the main valve block, as generally the only seals in a valve block are the ones at each end of the spool, to stop oil from leaking externally.

“Hydraulic spools in valve blocks are a machined precision fit, over time the spools can wear across the surfaces causing oil to pass between the internal galleries. Fitting a standard pilot operated check valve or over centre valve can stop this from happening.

“If the cylinder continues to creep, then the problem is with the internal seals of the cylinder. Once identified these seals can be easily replaced.”

Replacement seals for most applications can be picked up off the shelf. FPE Seals stock and supply a full range of seals, including piston seals for all engineered applications.

If you require any further advice regarding seals and their application, the team of experts at FPE Seals can help you source what you need.

Contact us today.

Question 6

What are hydraulic seals made of?

Accepted Answer

Hydraulic seals are non-metallic rings used in fluid power engineering, that prevent a fluid or gas from passing between different components of a cylinder, used in industrial applications.

Just as seals come in all shapes and sizes, for a multitude of applications, they also come in a variety of materials.

Most hydraulic seals use polymeric materials such a polyurethane, elastomers, rubber or polytetrafluroroethylene (PTFE).

The selected material of the seal will depend on the end use. Operating conditions such as high pressure, fluid compatibility, extreme temperatures, aggressive chemicals, working environment and legislation standards all impact on the chosen material.

Below are just some examples of common polymeric materials used to fabricate seals, utilised due to their hardwearing properties:

Polyurethane
Blue polyurethane (Food and Drug Association (FDA) compliant)
Nitrile
Viton/FKM
Silicone
Polyacetal (POM)
PTFE (in its virgin state or can be filled with either glass, bronze or carbon)
Ultra-high-molecular-weight polyethylene (UHMWPE)
Nylon
Polyether ether ketone (PEEK)
Polyester
Tufnol/Phenolic
AFLAS
NORSOK MATL (Oil & Gas industry compliant)

When choosing the right type of seal, to ensure the safe and optimum performance of a machine, seal material plays a big factor.

Not sure what you are need? Get in touch with our knowledgeable team here at FPE Seals, who will discuss your requirements based on your application, and help you find the right seal for the job.

Question 7

Why is it important to bleed the air from a hydraulic system?

Accepted Answer

Air that enters a hydraulic system can cause many problems that could subsequently lead to system failure. Here we discuss how you can spot and prevent these potential problems and why it is so important that air is bled from a system as soon as it is detected.

Hydraulic pumps are not designed to pump air, essentially because when compressed, air generates heat. When air contaminates a hydraulic fluid, usually via the pump’s inlet, aeration, cavitation, or foaming can occur.

Aeration is bad news, as it degrades the hydraulic fluid causing damage to the components of the system due to loss of lubrication, resulting in overheating and burning of the seals. Overheating is particularly dangerous as dieseling can occur when the hydraulic cylinder oil mixes with the air, causing an explosion under compression.

Cavitation, brought on by the rapid changes of pressure in the fluid, causes small vapour-filled bubbles to contaminate the system, which implode when compressed. Ultimately this leads to metal erosion, which harms the system’s components and contaminates the fluid.

Air can also cause foaming in the tank, causing the equipment to operate erratically, as the pump takes large gulps of air along with the oil.

When to bleed a hydraulic system

Abnormal noise is often a tell-tale sign that there is trapped air in a hydraulic system. As air circulates through the system it compresses and decompresses, creating a banging or knocking noise.

This is why abnormal noise must always be checked out and careful inspection given to the condition of the system’s fluid, components and seals, to identify any signs of trapped air or contamination.

It is also important that displacement hydraulic cylinders are bled before installation, as any air trapped in the system would work like a gas shock absorber. For this reason, displacement cylinders have a breather at the top, to disperse any air.

And lastly, when testing a new hydraulic cylinder, it is important to check for potential air contamination, as this can result in blowing the dirt wiper and the hydraulic seal out of its housing extruding past the rod.

All things considered, if spotted early and dealt with quickly, bleeding trapped air in a system, will prevent any long-term damage or operational downtime.

Question 8

How Are Hydraulic Seals Made?

Accepted Answer

Hydraulic and Pneumatic Seals for engineered machinery can be designed and manufactured in a variety of materials, shapes and sizes.

Selecting the right material

Most hydraulic seals are made from polymeric materials, more commonly polyurethane, polytetrafluoroethylene (PTFE), elastomers and rubber. Although, other materials can be used for more specialist seals.

It's important to select a material that best suits a seal's end use. For instance, the seal's operating conditions such as pressure, fluid compatibility, extreme temperatures, working environment and legislation standards, will all have an impact when deciding on which material to use.

Manufacturing process

During the manufacturing process, a Computerised Numerical Control (CNC) lathe machine is used to create the seal. These can be programmed with standard and customised seal profiles. Taking the digitalised data of the profile, the CNC lathe then works to cut the shapes of the seal from the selected material.

Take a look at our short video to see how seals are manufactured at FPE Seals.

Question 9

What is a Rod Seal?

Accepted Answer

Rod Seals, also known as Gland Seals, Headbush or Neck Seals are an integral part of any hydraulic or pneumatic cylinder system. Essentially, they are designed to seal between a cylinder’s rod and gland.

The Rod Seal acts as a pressure barrier to maintain and regulate the operating fluid when a cylinder is in dynamic motion, and so plays a key role in preventing leakage and corrosion.

They do this by sealing the pressure from one side (single-acting) or from both sides (double-acting) and work together with a Wiper Seal to protect the system from external contaminants.

For more heavy duty applications, a Buffer Seal can be used alongside a Rod Seal to provide even further resilience.

Rod Seals come in a variety of sizes, styles and materials, to meet the parameters of the cylinder’s application and operating conditions.

High pressure, extreme temperatures, fluid compatibility, working environment and legislation standards will all have an impact on the chosen material of seal.

The range of Rod Seals include;

Grooved Rod Seals – A single-acting seal with an anti-extrusion ring on the internal diameter.

Rod Composite Seals – Energised by an o-ring, to provide low friction, non-stick/non-slip hard-wearing sealing.

Rotary Rod Seals – used to seal a rotating shaft.

Rubber & Fabric Seals – when this type of material best suits the application.

T-Seals – T-shaped seal with two back up rings to help prevent extrusion.

Vee-Packing (Chevron) Seals – multiple-lipped seals packed together in groups of three or five, used in medium to heavy duty applications.

If you require any further advice regarding Rod Seals and their applications, then our knowledgeable team at FPE Seals would be happy to help.

We stock, source and supply a fully range of Rod Seals. Can’t find what you’re looking for? We can also manufacture the seals to your specification, in a full range of materials to meet your exact requirements.

Contact us today

Question 10

What Causes Hydraulics to Run Slow?

Accepted Answer

When it comes to a hydraulic system, a common complaint can be that it is operating slowly or less effectively than before. There are many reasons why this can occur, but this is mainly down to an issue with fluid flow and faulty or failing parts. Here we discuss the critical role that individual components play in hydraulics and why it may be that these components are causing the system to slow down.

Hydraulic Tank/Reservoir – to avoid any issues a good tank or reservoir should always come fitted with a filler breather, suction strainer, site glass, removeable inspection/service plate and drain plug.

Suction Strainer – this is designed to remove any foreign bodies that may have contaminated the tank. Filters must be checked and cleaned on a regular basis. If they become blocked, they will restrict the flow of the hydraulic fluid entering the inlet side of the pump, causing the system to slow down and ultimately causing damage to the pump.

Filler Breather – this should also be checked regularly, to make sure that the cage is intact and free from foreign bodies. Check the breather cap and if required, clean using an appropriate solvent, to avoid the breather element from becoming clogged. If blocked, this can cause the tank to vacuum, which will lead to a restricted flow of oil to the pump.

Suction Hose – a short piece of hose is fitted between the outlet of the tank and the inlet of the pump. Over time, the rubber hose can degrade, becoming porous, and even delaminate internally, causing a restriction of fluid flow into the pump.

Hydraulic Pump – modern day pumps are extremely complex pieces of engineering and usually will not tolerate any form of contamination. Any foreign bodies in a pump can cause severe damage to its integral moving parts, resulting in low pressure and restricted flow. Any problems can be identified with a good quality flow meter.

Power Unit – one component that definitely needs to be checked for any problems is the power unit that is driving the hydraulic pump. This can be an electric motor or either a combustion engine. These can be checked by loading the pump with a flow meter. The tone of the power source should alter slightly under load but not die. If the flow drops and the power source stays the same, it may be worth checking the drive coupling between the output shaft and the input shaft of the unit.

System Relief Valves – these are prone to overheating and will change colour when the incorrect pressure rating is too high. This can cause damage to the seating face in the cartridge, causing oil flow to pass over the seat of the relief valve and return back to the tank via the tank line. A faulty or dirty relief valve can also have the same effect if set to low, the valve will run continuously open, losing flow and causing heat.

Directional/Proportional Control Valves – these can be fitted with additional or external valves that can be easily altered or damaged causing them to pass oil across and dumping it back to the tank. Always remember, any fluid will always take the easiest route away from the tank. The smallest imperfection on a seat, that cannot be felt but can be seen, will allow oil to pass.

Hydraulic Cylinder – just because there are no external signs of leakage does not mean to say that the internal piston seals of the cylinder are not worn or damaged. Although, usually there are identifying signs that the piston seals are worn. For instance, the cylinder may be dropping or have no lifting force.

In general, if your hydraulic system is running slowly when the fluid warms up, then this is due to the oil thinning and therefore able to pass easily across worn or damaged surfaces. Carrying out a simple flow test with a flow meter will help eliminate any of the key factors mentioned above.

Question 11

What is a Wiper Seal?

Accepted Answer

Wiper Seals, also known as Scraper Seals or Dust Seals are primarily designed to prevent contaminants from getting into a hydraulic system.

This is usually achieved by the seal having a wiping lip that essentially cleans away any dust, dirt or moisture from the rod of a cylinder on each cycle. This type of sealing is crucial, as contaminants can potentially cause damage to the other components of the hydraulic system, and cause the system to fail.

The wiping lip always has a smaller diameter than the rod it is sealing. This provides a tight fit around the rod, to prevent any dirt getting in, when in both a static and dynamic position, while still permitting a reciprocating ram rod to pass through the inner bore of the seal.

Wiper Seals come in range of different styles, size and materials, to best suit the application and operating conditions of a fluid power system.

Some Wiper Seals have secondary functions, this may include having a harder scraping lip to remove stubborn contaminants such as bonded dirt, frost or ice, or a secondary lip used to capture any oil that may have bypassed the main seal. These are commonly known as Double Lipped Wiper Seals.

In the case of a Flexible Wiper Seal, the seal is usually held in by its shoulder.

A Metal Cased Wiper Seal relies on the outer metal case having an interference fit to hold it in the housing. It will therefore measure slightly larger on the outside diameter.

If you require any further guidance on Wiper Seals, then our knowledgeable team at FPE Seals would be happy to help.

We stock and supply a fully range of Wiper Seals. If you can’t find what you’re looking for, we can also manufacture the seals to your specification, in a full range of materials to meet your exact requirements.

Contact us today

Question 12

Why Are Hydraulic Cylinders Cushioned?

Accepted Answer

Cushioning or soft start as it is sometimes referred to, is used to slow down a hydraulic cylinder, by reducing the speed of a piston at the end of its stroke, or before it meets the end cap. These are generally used in double-acting cylinders, for heavy duty applications that use a lot of kinetic energy.

Cushioning is commonly fitted to both the rod side and full-bore side of a cylinder, to bring the final movement of the rod to a stop. This prevents the piston from slapping against the back of the gland and the end cap of the cylinder when opening and closing.

The ultimate purpose of using a cushioning method is to avoid damage to the piston, which could occur when a high oil volume is applied to a hydraulic cylinder.

Other advantages of using a cushioning method are that it extends the life of the cylinder by reducing the impact of vibrations, as well as reduces any excessive audible noises.

How does hydraulic cylinder cushioning work?

Hydraulic cylinders operate by pumping a medium into the cylinder causing the piston to extend or retract to the end of its stroke.

A cushioning device works on the principle of forcing a small amount of the cylinder fluid through or over a smaller diameter / orifice which is usually present to the front or rear of the piston, as it comes to the end of its travel.

The cushioning device therefore restricts the flow of fluid to the back of the neck gland or base of the cylinder, which ultimately slows down the stroke of the cylinder as the fluid cannot go anywhere else, apart from through the tolerance aperture of the gland, resulting in slowing down the stroke to a stationary finish.

It is always best to decide whether to fit a cushioning device at the initial design and build stage of cylinder, as retro fitting can be a very costly.

Should you want any further advice on cylinder design and cushioning components, please contact our knowledgeable and helpful team today.

View our range of Non-Adjustable Cushioning Glands and Pistons.

Question 13

Why Do Hydraulic Cylinders Fail?

Accepted Answer

Hydraulic cylinders come in all shapes and sizes and are used in a variety of applications. The reasons why a cylinder can fail will depend on their application but in general, most problems are usually down to either physical damage or seal deterioration.

If a cylinder is misused or has been physical damaged in some way, it can become a pressure intensifier, which causes harm to the different components, from misalignment, to the piston being pulled from the rod, to the drastic results of the cylinder splitting its full length.

All cylinders are pressure-rated based on their application. Most are designed to work at 250bar, which normally applies to the extrusion tolerance of the seals used in the cylinder’s different components.

Seals will wear slowly over time, this cannot be prevented but is easily solved by spotting any problems early and replacing the worn seals, without causing any major issues to the hydraulic system.

However, excessive pressure, heat, misuse, and poor fluid condition will cause seals to deteriorate rapidly. For example, the seals can harden, crack, or extrude.

How to prevent cylinder failure

Areas to typically look out for cylinder failure is between the rod and the gland, the gland itself, the cylinder and around the welded parts.

All cylinders should be checked externally on a regular basis. Especially at the mounting points, steel pipes and hydraulic hose fitting. Anything that is loose should be rectified immediately. Make sure that there is sufficient lubrication and look out for any areas of excessive wear. Worn areas should be addressed without delay.

Particularly, check all external mechanical stops, as any damage can result in the piston or gland being pulled from its threads.

Inspect the condition of the chromed rod that moves back and forth in the cylinder. Any external dents, rust, scrapes or bends could lead to severe damage to the other integral components of the cylinder.

Always check the fluid levels of your hydraulic system, change the filter regularly and keep fluids free from contamination. This will prevent seal failure and damage to the cylinder bore.

Overall, cylinder failure can easily be prevented with careful use, regular inspection, and servicing, ultimately reducing the need for costly repairs and downtime.

If you would like any advice on sourcing replacement metal parts or seals for your hydraulic ram, please contact our helpful and knowledgeable team today.

Contact Us

Question 14

What is a Piston Seal?

Accepted Answer

Piston Seals, essentially provide a seal between a piston and cylinder bore.

The seal prevents leakage of hydraulic fluid or air, sealing dynamic pressure from one or both sides of a ram, to allow the cylinder to extend and retract.

Piston Seals are dynamic by nature and come in a range of different styles, sizes, and materials. The type of seal needed will be dependent on the design of the cylinder, the application, the medium used, and its operating conditions.

Single-acting Piston Seals contain the pressure and prevent leakage on one side of the piston only. Therefore, the seal moves the piston along the cylinder in a single action.

Double-acting Piston Seals contain the pressure and prevent leakage from both sides on the piston. This drives the hydraulic or pneumatic ram both in and out, or stops it in a controlled position. Typically, double-acting seals have a symmetrical profile, with identical sealing functions on both sides.

Back up rings and guide rings are also commonly used alongside piston seals, to reinforce the seal and ensure that it stays in the correct position.

If you require any further advice on selecting the right Piston Seal for you, our knowledgeable team would be happy to help.

FPE Seals stock and supply a comprehensive range of Piston Seals, Piston Rings and Cylinder Parts.

If you are are unable to find what you are looking for on our web store, please let us know. Our inhouse manufacturing team can create seals to specification, in a wide range of materials to best meet your requirements.

Contact us today

Question 15

Why Is My Excavator So Slow?

Accepted Answer

Tim Bone, Cylinder Parts Manager, FPE Seals explains some of the reasons why an excavator can be operating slowly.

“Modern day excavators come in many shapes and sizes, with most now fitted with more than one hydraulic pump, along with various system relief valves, service relief valves and priority valves to make the excavator run more smoothly.

Generally, there are two main hydraulic pumps, one for each of the track motors and possibly a smaller displacement pump for the pilot circuit. Reasons as to why an excavator is running slowly, can be down to the two main hydraulic pumps, as it is these that are primarily designed to power the main function of the excavator.

An excavator’s load is spread equally across both pumps. On its return, flow it is diverted through a loading valve or regeneration valve, combining both flows and giving the extra power needed to the required cylinder, resulting in a better tear out force.

Check the power

An excavator’s two power supplies, the engine and the hydraulic pumps, are driven through a flexible drive coupling. The first signs of a problem will show when an excavator tracks to one side or some of the functions are slow, while others are working normally. If all the functions are slow then this might be a sign that the power unit has a fault, or the drive coupling is worn and slipping.

First check the power unit. Is the engine struggling? Do the revs of the engine increase under load or do they die off as though the engine is struggling to increase its power band?

Basically, if the engine is not running correctly or in need of a service, then it cannot provide the necessary power for the hydraulic pumps to supply the flow to run the system.

Engines need to be serviced regularly. Diesel filters need to be kept clean and free from contamination. Remove and replace the air filter if this has got very dirty.

Secondly, check the flexible drive coupling. This could be worn, shattered or even slipping on the drive shaft. Drive couplings wear out as the rubber segment that gives it the flexibility take a lot of stress. Also check the hydraulic fluid levels, if the suction strainer is blocked this can cause cavitation and starvation to the pumps.

Process of elimination

Finding a fault on any machine is time consuming, but using a process of elimination component by component will make a diagnosis easier. Try not to think that the problem is a major component, in the majority of cases it is often something very simple like an O-ring or a damaged seat of a valve.”

FPE Seals provide hydraulic seals and cylinder parts for excavators, contact our knowledgeable team today who will help find you what you need.

Question 16

The History of Hydraulics:  Then to Now

Accepted Answer

Hydraulics is the technology and applied science, that uses fluid for power.

The first hydraulic systems date back thousands of years, with irrigation and water clocks being used by ancient Greeks and Egyptians, as early as 600 BC.

The Persian Empire, Roman Empire, ancient Greek, Chinese and Arabic societies that followed, each brought their own early innovations of hydraulic machinery, such as watermills, water wheels, water turbines, mining equipment, and the first known steam engine (known as an Aeolipile).

DID YOU KNOW?

The word "hydraulics" originates from the ancient Greek word "hydraulikos" meaning water (hydor) pipe (aulos).

Hydraulic technology has come a long way since then and can be found being used in a wide variety of applications every day, across the world.

Pascal's Law

Pivotal in setting the foundations for all modern hydraulics, was gifted French mathematician, physicist, and philosopher Blaise Pascal.

In 1640's, while studying hydrodynamics, he discovered a mathematical equation, known as 'Pascal's Law', which pronounced the principle of transmission of fluid pressure.

Pascal's law realised that pressure on a fluid in a confined area, remains constant in all directions and that this force could be harnessed.

Bernoulli's Principle

Nearly a 100 years later in 1738, Swiss mathematician and physicist Daniel Bernoulli put Pascal's fluid power discovery to use by pressurising water in pumps and mills using Bernoulli's principle.

First Hydraulic Press & the Industrial Revolution

Engineers soon began experimenting with functions of the principle described in Pascal's Law. One such engineer was Englishman Joseph Bramah, who in 1795 patented a design for a hydraulic press, paving the way for the industrial revolution.

The press used a hydraulic cylinder to harness fluid power to generate a compressive force, which then was used to produce mechanical force. This was used to automate all types of manufacturing and heavy-lifting equipment, such as printing presses, cranes, and machines that involved cutting, stamping, and crushing.

From water to other fluids

While water was always the primary fluid hydraulic fluid used, engineers soon discovered that there were better options out there, to best suit specific applications.

Oil was regarded as a better alternative for pumps and motors, as unlike water it was non-corrosive, lubricated the components, and could handle high temperature and pressure.

Nowadays, there are a whole host of different fluids being used in hydraulics systems. Hydraulic fluids are selected based on the compatibility with the operating conditions of the application, considering qualities such as the fluid's density, viscosity, and response to heat and pressure.

Modern day hydraulics

Fast forward to modern day, hydraulic systems are used all over, in a variety of ways. From heavy plant and mining machinery, to agricultural equipment and manufacturing facilities, through to deep sea, marine and automotive applications, to hand tools and household appliances, the list goes on and on.

Innovation in the field of hydraulics continues, with new hydraulic systems and equipment being designed and tested every day.

If you need any advice regarding your hydraulic cylinder design, or help to source the seals and metal parts needed, please contact our knowledgeable team, who would be happy to help.

Question 17

What are Oil Seals?

Accepted Answer

Oil Seals, also known as fluid seals, grease seals, dirt seals, shaft seals, or lip seals, help to seal the gap between static and moving components in machinery and equipment. Oil Seals used in rotating applications are known as rotary seals.

These seals are more commonly used in pumps, motors both electric & hydraulic, gearboxes & occasionally dirt wipers in hydraulic cylinders. They help protect shafts and bearings from dirt and harmful contaminants entering the internals of the application that they are fitted too, as well as prevent any leaks of lubricant.

How are Oil Seals made?

Generally, an oil seal is made up of an outer circular metal part and a bonded inner flexible material (often nitrile rubber) that does the actual sealing.

The sealing effect is achieved by manufacturing a smaller inside diameter than the required shaft size, which preloads the sealing lip. A garter spring is often used to ensure a constant force on the shaft.

Nitrile rubber offers good durability for general use, while the flexibility of the spring behind the sealing lip keeps the oil seal firmly in place against the moving part.

How to Choose the Right Oil Seal

There are several key factors to consider when selecting the right oil seal to best protect your application.

1. Pressure: Many oil seals are used in high-pressure applications, so understanding the working pressure of your components is very important.

2. Temperature: Just like pressure, it is very important to choose the right seal that can withstand extreme heat or cold temperatures, depending on the operating environment of your application.

3. Fluid types: Oil seals interact with oils, fuels, grease, water and more. Choosing a seal material that is most compatible with your chosen medium can help to increase the durability of the seal and its internal components.

FPE Seals range of Oil Seals:

FPE Seals offer a comprehensive selection of Oil Seals and Rotary Seals in a range of different styles, materials, and sizes to best meet your needs.

Available to order online today.

Can’t find what you are looking for or require something more customised?

Our experienced in-house machined seals team can design and manufacture what you need in a wide range of standard and specialist materials, including NORSOK M-710 approved materials suitable for the Oil & Gas industry.

Question 18

What is the difference between hydraulic and pneumatic applications?

Accepted Answer

Engineering and automation industries, generally rely on applications that are powered by either electric, hydraulic, or pneumatic systems.

Hydraulic and pneumatic applications are very similar in that they both channel mechanical energy using similar components. The main difference between the two is the medium used to transmit the force.

Hydraulics are pressurised liquids like oil, water, or synthetics.

Whereas pneumatics operates by using easily compressible air or gases.

difference between hydraulic and pneumatic applications

When it comes to maintaining the pressure of either liquids or gases, sealing plays an important role.

The difference between Hydraulic seals and Pneumatic seals

Hydraulic seals and pneumatic seals are the same in application but totally different in construction.

Hydraulic seals are designed to work in a harsher environment and to withstand moveable forces.

Whereas Pneumatic seals must be more flexible and have a less friction application due to operating at lower pressures.

Both hydraulic and pneumatic seals are used across a wide range of industries including but not limited to construction, plant, manufacturing, oil & gas, automotive, pharmaceutical, and food & beverage production.

FPE Seals stocks and manufactures a full range of sealing solutions and metal parts for both hydraulic and pneumatic applications. From piston seals, wiper seals, O-rings, and cylinder components.

Order online today or get in touch with our knowledgeable team here at FPE Seals, who will discuss your requirements based on your application, and help you find the right seal for the job.

When choosing the right type of seal, to ensure the safe and optimum performance of your machinery, seal material plays a big factor.

Not sure what you need? The FPE Seals team is happy to advise or download our Fluid Compatibility Table for guidance.

Question 19

What are couplings used for?

Accepted Answer

The word “coupling” can be used to describe a range of different components in the field of engineering.

There are mechanical couplings as found on drive shafts connecting two units together, as well as threaded couplings, to name but a few. In this blog we discuss Hydraulic Couplings used in the fluid power sector.

There are many different types of Hydraulic Quick Release Couplings available on the market today. Selecting the best coupling for a particular application is extremely important.

Selecting the right coupling for your application

There are many things you will need to consider that centre around the operating conditions it will be exposed to, such as:

• Flow rate of the equipment being used
• Flow rate of the hydraulic power unit
• Working environment e.g. Construction, Agricultural, Marine
• Ease of connection under pressure
• Cost

FPE Seals offers a range of couplings:

Flat Face Couplings: These couplings allow for minimal inclusion of contaminants during connection and prevent fluid loss and come with a unique locking method. Typical applications include excavator hammer circuits, hydraulic hand tools and breakers, mobile equipment, general industrial, mining, and agricultural.

Quick Release Couplings: Various quick release couplings are commonly used in fuel systems, cooling, test rigs, air tools, and agriculture.

ISO A Poppet valves have balanced springs and a locking ball system that allows quick connection, by pulling back the locking ring, Traditionally, a very versatile coupling, used in lots of equipment, these are now becoming more outdated, and in some cases, flat faced couplings may be a better option.

FPE Seals stocks and manufactures a full range of sealing solutions and metal parts for both hydraulic and pneumatic applications.

Our knowledgeable and experienced Cylinder Parts team can offer advice to help you select the most appropriate component to suit your application.

Order online today or get in touch.

Question 20

What is the Difference Between Gaskets & Seals?

Accepted Answer

Choosing between a gasket and a seal can be confusing, as in many ways they essentially do the same thing. But there are some important differences to note, when deciding which is right for your specific application.

Gaskets provide a seal between static flat components like joints and flanges, while seals are used on active applications with significant movement between components as a result of rotation or reciprocation such as rotating shafts, pistons and pumps.

What is a Gasket?

Gaskets are used in static applications; the primary function of a gasket is to prevent leaks and over compression. Normally, a gasket is used to seal two mating surfaces that have a machined finish and space is limited.

Gaskets can be used for applications where there is an aggressive environment, substance, or liquid present. These are more commonly used in industries such as oil and gas, pulp and paper production, agricultural equipment, and transportation.

What is a Seal?

Seals help to prevent leakage in dynamic applications between two moving parts and prevent dirt or contaminants entering the system.

There is a broader range of seal types and profiles such as rotary seals, pneumatic seals, wiper seals and piston seals. Which are more commonly found in applications like hydraulic rams, motors, engines, pumps, and rotary shafts

Typically, seals are used in industries such as construction, manufacturing, food & beverage production, oil & gas, automotive and agriculture.

What are gaskets & seals made of?

Gaskets and Seals are manufactured in a range of materials.

These include Nitrile, Flourosilicone, Polyisoprene, Neoprene, Polyurethane, Silicone, Synthetic Polyisoprene, Thermoplastic Rubber (TPR) and Viton® depending on the application and working environment.

Let the experts at FPE Seals help you find the right seal or gasket for your next project.

Can’t find what you are looking for or require something more customised?

Our experienced in-house machined seals team can design and manufacture what you need in a wide range of standard and specialist materials.

Question 21

What Causes Hydraulics Cylinders to Leak?

Accepted Answer

Almost all hydraulic cylinders within their working lifetime will show signs of a leak. However, if issues are spotted early enough leaks can be minimised and easily fixed.

Here we look at some of the main causes of leaks in hydraulic cylinders and how to prevent them.

How to spot an internal hydraulic leak in a cylinder.

If you notice a pressure change in your hydraulic cylinder, or the cylinder starts to drop under its own weight, chances are there is internal leakage across the piston seal Fluid that leaks into other areas of the cylinder, affects the motion of the rod. This causes the movement of rod in the cylinder to slow down, as it disperses the fluid to get back into the open position.

Another tell-tale sign of a leak, is a visual leak and having to replenish the hydraulic fluid in your machine more frequently than usual, causing an increase in your operating costs.

Main causes of a hydraulic cylinder leak

Wear & Tear

A worn or damaged Piston seal or cylinder component can cause fluid leakage. Even the tiniest of cracks can cause hydraulic fluid to enter other parts of the system.

Although the wear is unlikely to be visible without closer inspection, a drop in the machinery’s performance is usually an indicator that there is a problem within the cylinder, and its individual parts should be assessed.

Contamination

Dirt, debris, or small pieces of metal that break off other parts of the machine and enter the system can damage components within a hydraulic cylinder and cause an internal leak.

Contaminated hydraulic fluid such as water can cause a white milky fluid, which invariably results in corrosion. Some biodegradable oils if not changed regularly at service intervals can break down and cause sludging and components to stick.

Ensuring that your cylinder is kept well lubricated and protected from external contaminants will prevent this problem from occurring. If you suspect your hydraulic fluid is contaminated, you should flush and replace the fluid as quickly as possible.

Poor maintenance

Problems can occur if the individual components of a hydraulic cylinder have been poorly fitted or maintained. For instance, if seals are fitted incorrectly or over-tightened this can cause the seal to crack and lead to the deterioration of other parts over time.

Ensuring the cylinder is properly fitted by a skilled engineer and kept regularly lubricated, will prevent this from happening.

Changes in operating conditions

Exposure to high temperatures, or heat from high-speed or overuse can damage the seals and O-rings within your hydraulic cylinder and cause it to leak.

Therefore, it is vital to take a machine’s operating conditions into account when selecting the right seals and parts for your cylinder. Some applications require seals manufactured in materials that can withstand high temperatures and high pressure.

Replacing hydraulic cylinder seals and parts

FPE Seals provide replacement parts for all hydraulic cylinders and specialise in providing sealing solutions for aftermarket applications.

View what is on offer on our website or contact one of our knowledgeable team today who are happy to advise on finding you the best part for the job.

Question 22

What are Hydraulic Cylinders used for?

Accepted Answer

Hydraulic cylinders have a variety of uses and can be found in machinery and equipment across many different industries including

construction, agriculture, manufacturing, earth-moving and mining, food and beverage processing and packaging, deep sea, marine, and transportation.

In general, hydraulic ram cylinders are used in applications that lift heavy loads, push, pull or rotate, or in equipment such as hydraulic presses, which use pressurised fluid to exert force on an object.

How do hydraulic cylinders work

Hydraulic cylinders use fluid from an external pump driven by a power unit.

Cylinders are designed based on the on the rule that liquids are incompressible. The result therefore being that when a force is applied at one point of a cylinder, the liquid will transfer an equal force at another point.

Most common hydraulic devices work by using a hydraulic pump, a reservoir for fluid storge to the pump. Mechanical energy is converted to hydraulic energy, moving the liquid through a system. Valves are used to regulate the flow of the liquid and control the pressure of the device. A hydraulic cylinder then converts the hydraulic energy back into mechanical energy.

They are used to lift heavy loads

Hydraulic cylinders can push, pull, and lift loads of any description. Commonly, they are used in mobile applications, such as excavators, loaders, graders, dumper trucks, backhoes or dozers, or any mobile machinery that requires a linear motion to move loads.

They are used in industrial machinery or equipment

Hydraulic cylinders are commonly found in industrial settings where large amounts of power are needed to operate machinery. This makes them ideal for use in many industrial applications such as presses, compactors, and injection moulding to name but a few.

They are used to operate machines

Many industries used hydraulics to power their machinery and equipment. For example, the food and beverage industry sources power from hydraulic cylinders to process, position and package food and drink products.

The agricultural sector extensively uses hydraulic-powered machines such as tractors, loaders, spraying equipment, skid steers, balers and harvesting equipment, to plant and harvest crops and rear livestock.

But these are just a couple of examples, hydraulics can be found across a multitude of industries, for a variety of uses from the largest of industrial equipment to the smallest of hand tools.

FPE Seals stocks and manufactures a full range of sealing solutions and metal parts for hydraulic cylinders. From piston seals, wiper seals, O-rings, and cylinder components.

Order online today or get in touch with our knowledgeable team here at FPE Seals, who will discuss your requirements based on your application, and help you find the right seal for the job.

Question 23

What are four major factors you need to consider when choosing adhesives?

Accepted Answer

Different adhesives have different properties, allowing them to be used in many different circumstances. As such, the type of adhesive you need will depend on the type of project you’re working on and what your ultimate goal is.

There are several key factors to bear in mind when choosing adhesives. To help you choose the right adhesive for your specific job, we look at four factors you should consider.

The Type of Surfaces You’ll Be Bonding

A major factor to consider when choosing adhesives is the surfaces you’ll be bonding together. This will help you determine which type of adhesive is best for your project.

For example, if you’re bonding rubber to metal, you’ll want to use a rubber-toughened superglue. If you’re joining glass, you’ll want to use a special adhesive designed for glass.

There are various types of adhesives for different surfaces. For example, there are adhesives suitable for wood, plastic, glass, and metal. There are also adhesives for specific materials like ceramics and fabrics. There are even specialty adhesives for specific projects like hydraulics, plumbing, gardening, and repairs.

The Adhesive’s Working Life

When choosing adhesives, you will also need to consider the adhesive’s working life. This refers to the amount of time you have before the adhesive dries and bonds the two surfaces together.

Depending on the project and adhesive you’re using, you may have anywhere from a few minutes to a few hours before the adhesive is completely set. This is something to keep in mind because it’ll help you determine the best way to approach the project.

For example, if you’re using a general adhesive and you have only a few minutes before the surface is dry and fully bonded, you’ll need to work quickly. On the other hand, if you have a few hours before the two surfaces are fully bonded, you’ll need to approach the project more methodically.

How Much Weight the Adhesive Can Hold

Depending on the project you’re working on, you may need to know how much weight the adhesive can hold. This is especially important if you’re using an adhesive to join materials together that will be used to hold heavy objects.

For example, if you’re joining industrial materials together, you’ll want to use an adhesive that is rated for heavy-duty applications. This way, you can rest assured that the materials will stay bonded together even under heavy pressure.

Additional Options and Recommendations

With each adhesive, you’ll find a range of specific additional options and recommendations, it is important that you always follow the product’s instructions and guidelines. This will ensure that you get the most out of the product and that is used safely.

For instance, certain adhesives work best when used outdoors. Every type of adhesive will have a recommended drying time you must follow. Some adhesives will be incompatible with specific materials.

Choosing the right adhesive for your project can be a daunting task. This is because there is a wide range of different adhesives to choose from, each with its own set of advantages and disadvantages.

To make the process easier, you’ll need to consider all the above, however, if you are still unsure it is always best to speak to an industry expert or to contact the provider directly.

FPE Seals supplies a range of adhesives suitable for a wide range of industries including hydraulics, pneumatics, automotive, manufacturing, industrial, and medical equipment.

Check out the full range here

Question 24

Why do hydraulic cylinders creep, and how to prevent it?

Accepted Answer

Hydraulic cylinder creep is a common issue, that can occur when a hydraulic cylinder fails to maintain its position. This can be caused by a variety of factors, including internal leakage within the cylinder caused by damaged or worn seals, or improper fluid viscosity.

To prevent hydraulic cylinder creep, it is important to regularly maintain and inspect the cylinder and the hydraulic system, and to use the most compatible fluid.

Never Ignore the Signs of Hydraulic Cylinder creep

Ignoring the signs of hydraulic cylinder creep can lead to several serious problems. For one, the cylinder may fail to maintain its position, which can cause dangerous situations depending on the application. For example, if the cylinder is used in a lifting application, it may drop the load it is holding, potentially causing injury or damage to property.

Additionally, ignoring the signs of hydraulic cylinder creep can cause damage to the cylinder and the rest of the hydraulic system, leading to costly repairs or replacement.

Regular maintenance and inspections can help to prevent hydraulic cylinder creep and ensure that the system is functioning properly.

How to prevent hydraulic cylinder creep?

There are several steps you can take to prevent hydraulic cylinder creep. Here are a few tips:

Regularly maintain and inspect the hydraulic cylinder and system. This can help to identify and address any issues before they become more serious.
Use the proper fluid for the system. Different applications may require different types of hydraulic fluid, so it's important to use the correct one to ensure optimal performance.
Use high-quality seals and other components in the hydraulic system. This can help to prevent leaks and other issues that can cause creeping
Avoid exposing the cylinder to extreme temperatures or other harsh conditions. This can cause the fluid to break down or the seals to become damaged, which can lead to the cylinder creeping

Overall, regular maintenance and attention to detail are key to preventing hydraulic cylinder creep. By taking these steps, you can help to ensure that your hydraulic system is functioning properly and can avoid costly repairs or downtime.

Looking for a replacement part for a hydraulic cylinder, either for service or repair work or an engineering design project but unsure where to start?

Contact us today, our experienced and knowledgeable team can offer technical support and advice with your cylinder design and help you find the right part for the job.

Whether you are after something off-the-shelf or something custom made, we offer OEM quality products at aftermarket prices, are quick to respond, have a wide range of stock on hand, as well as an in-house manufacturing capability.

Question 25

What is a hydraulic cylinder and how are they used on excavators?

Accepted Answer

Hydraulic cylinders are used effectively in a variety of applications to move heavy loads. This is because of their ability to generate large amounts of force using pressurised fluid, with relatively small amounts of input power.

Different applications of hydraulic cylinders.

Some common applications for hydraulic cylinders include:

• Construction: used in plant and earth-moving equipment, such as excavators and bulldozers, to power the movement of the boom, dipper and bucket cylinders . Tracking the excavator back & forth.

• Manufacturing: used in production and processing equipment, such as stamping and pressing, to apply large amounts of force to shape or cut materials.

• Agriculture: used in farming equipment and machinery for services such as transportation, planting, feeding, drilling, cultivation and harvesting.

• Food and Beverage: used in wide variety of equipment to process and package food and drinks.

• Automotive: to power the brakes, steering and suspension systems in certain vehicles.

• Aerospace: used in aircraft to power the movement of the flaps, landing gear, airstairs and other control surfaces.

How Do They Work?

Hydraulic cylinders in an excavator work by using pressurised hydraulic fluid to generate a force that can be used to manoeuvre the excavator and move the boom, dipper and bucket. The control valve is used to control the flow of fluid into the cylinder, allowing the operator to move the boom, dipper and bucket with precision.

Typical cylinders found in Excavators & Mini-Excavators.

There are different types of cylinders found on excavators and mini excavators, each with its very own specific function.

1. Bucket cylinder: These cylinders are used to power the movement of the bucket, that is located on the end of the dipper arm. Bucket cylinders are typically smaller than boom cylinders and are used to move the bucket and to control its angle during excavation.

2. Boom cylinder: These cylinders are used to power the movement of the main boom, up & down. Boom cylinders are typically larger and more powerful and can generate significant amounts of tare out force to move the boom when working.

3. Dipper cylinder: The Dipper arm cylinder, also known as the stick or crowd it is used to power the movement of the arm which carries the bucket.

4. Rotary Unions: This unit is used transfer fluids from the excavator to the undercarriage of the machine. This allows the operator to change the direction the excavator is facing, which is important for manoeuvring the bucket in different directions or for dumping material.

5. Swing cylinder: A swing cylinder also known as a slew cylinder, is a hydraulic cylinder that is used in excavators to offset the upper part, of the boom about a vertical axis. This allows the operator to change direction, which is important for manoeuvring the machine in tight spaces or when digging in different directions.

6. Track Adjuster: The track adjuster is typically located in the undercarriage of the tracks and consists of a hydraulic cylinder that is connected to the track frame. When the cylinder is extended by pumping grease into the cylinder it adjusts the tension in the tracks.

7. Dozer: A dozer cylinder, also known as a blade cylinder, is used on mini excavator to raise and lower the dozer blade. The dozer blade is used to push or move materials, such as dirt, sand and helps in assisting the stability of the excavator.

8. Vari Width cylinder: This cylinder is fitted in the undercarriage to move the tracks in & out. On smaller excavators, this helps to increase the stability and allows the excavator to manoeuvre through narrow gaps greater than 900mm.

FPE Seals provide aftermarket replacement seal kits at OEM quality, for the hydraulic cylinders on an excavator, for 1000's of leading plant and engineering brand's equipment models.

FIND THE KIT YOU NEED TODAY

Question 26

How did tractors impact the agricultural industry?

Accepted Answer

The revolution of the tractor has had a significant impact on the agricultural industry, increasing the efficiency and productivity of farming.

Prior to the invention of the tractor, farmers primarily relied on horses and other draft animals to plough fields and perform other tasks. The tractor, with its internal combustion engine and hydraulic system, was able to replace the work of many animals, allowing farmers to cultivate more land and produce more crops.

In this blog, we discuss the history of the tractor and how the use of hydraulics has transformed farming.

History of the tractor

The history of the tractor dates to the late 19th century when inventors began experimenting with steam-powered and gasoline-powered engines for use in agriculture. The first successful gasoline-powered tractors were developed in the early 1890s, with the most notable being John Froelich's "Froelich tractor" which was built in 1892.

During the early 20th century, many companies began to produce tractors, including the Fordson, which was first produced by Henry Ford in 1917. The Fordson, along with other tractors of the time, such as the International Harvester and Allis-Chalmers, were primarily used for ploughing and other tillage tasks.

In the 1920s and 1930s, tractors became more versatile, with the development of models that could be used for a variety of tasks, including planting, harvesting, and hauling. The introduction of rubber tyres and power take-offs (PTOs) also greatly increased the versatility and efficiency of tractors.

In recent decades, tractors have continued to evolve and improve, with the introduction of new technologies such as hydrostatic transmissions, electronic controls, and GPS systems. Today, tractors are an essential part of modern agriculture and are used in a wide range of applications, including large-scale commercial farming, small-scale subsistence farming, and even in construction and landscaping.

How hydraulic systems are used by the agricultural industry

Hydraulics are widely used in agriculture for a variety of applications, including:

Tractor operation: Tractors use hydraulic systems to control their movements, including steering, lifting, and lowering.
Harvesting machinery: Hydraulics are used in combine harvesters, balers, and other harvesting equipment to control their movements and adjust the speed and flow of material being processed.
Irrigation systems: Hydraulic systems are used in centre pivot irrigation systems to control the movement of the sprinkler and regulate the flow of water.
Plough and cultivators: Hydraulic systems are used in plough and cultivators to control the depth and angle of the blades.

Benefits of using hydraulics for agriculture

Hydraulics bring several benefits to the agricultural industry, including:

Precision control: Hydraulic systems provide precise control of movement and power transfer in farm machinery, enabling accurate and efficient operations.
Increased efficiency: Hydraulics allow for smoother and consistent operation of machinery, reducing downtime and improving productivity.
Durability: Hydraulic systems are designed to withstand harsh conditions, reducing wear and tear on equipment, and extending its lifespan.
Safety: Hydraulics offer greater safety for operators, reducing the risk of injury or accidents while working with heavy machinery.
Versatility: Hydraulic systems can be easily adapted to different types of farm machinery, making it a versatile and cost-effective solution for the agriculture industry.
Comfort: Hydraulics provide a more comfortable working environment for operators, reducing fatigue and improving their overall experience.

In need of hydraulic cylinder seals and parts?

FPE Seals have been trusted supplier for agricultural customers for many years and have a particular expertise in providing sealing solutions and hydraulic cylinder parts for aftermarket equipment and machinery used in this sector.

View what is on offer on our website or contact one of our knowledgeable team today who are happy to advise on finding you the best part for the job.

Question 27

How to prevent hydraulic cylinder cavitation

Accepted Answer

Cavitation is the formation of vapour bubbles in a flowing liquid. When the bubble rapidly collapses, it produces an intense shock wave which rapidly erodes contact surfaces. If a pump suffers from cavitation, it will be very noisy and suffer from early failure.

Should this take place in within a hydraulic system, it can bring about a cascade of harmful issues that can eventually ruin essential (and expensive) components, resulting in system failure. While most people identify cavitation problems with pumps and motors, cavitation can also occur in hydraulic cylinders.

Problems caused by cavitation in a hydraulic cylinder.

• Damage to hydraulic components: The air bubbles formed during cavitation can damage hydraulic components such as pumps, valves, and cylinders by erosion or pitting the surfaces they come in to contact with.

• Noise: Cavitation can generate loud noises, which can be annoying for operators and can potentially damage hearing if exposed to for an extended period of time.

• Premature Seal Failure: Cavitation can cause the seals with a hydraulic cylinder surface to wear, erode or deteriorate, causing premature seal failure.

• High fluid temperatures: Cavitation can cause temperature above 180° F (82° C) will damage seals and accelerate degradation of the fluid. In addition to damaging seals and reducing the service life of the hydraulic system.

• Fluid contamination: Cavitation can cause the release of debris and other contaminants into the hydraulic fluid, which can lead to further damage to the system and reduce efficiency.

Preventing Cavitation

• Inspect and replace worn components on a regular basis: Regular inspections of the hydraulic cylinder can help identify any worn or damaged components that need to be replaced.

• Keep the hydraulic system clean: Clean the hydraulic system on a regular basis to prevent contamination from dirt or other debris. To avoid contamination, it is also critical to use high-quality hydraulic fluid.

• Align components properly: Make sure that all hydraulic cylinder components are properly aligned to prevent uneven movement.

• Monitor hydraulic pressure: Keeping hydraulic pressure within the recommended range can help prevent excessive pressure.

• Remove air from the hydraulic system: Bleed the hydraulic system on a regular basis to ensure that there is no air in it. This will prevent the piston from moving unevenly because of the compressibility of the air.

Looking for a replacement part for a hydraulic cylinder, either for service or repair work or an engineering design project but unsure where to start?

Contact us today, our experienced and knowledgeable team can offer technical support and advice with your cylinder design and help you find the right part for the job.

Whether you are after something off-the-shelf or something custom made, we offer OEM quality products at aftermarket prices, are quick to respond, have a wide range of stock on hand, as well as an in-house manufacturing capability.

Question 28

How do I know if my pneumatic seal needs replacing?

Accepted Answer

Pneumatic Seals are used in a wide variety of applications across haulage, construction, plant, pharmaceutical, food, and general engineering industries, improving equipment performance. They are designed to keep the gases and fluids under pressure, helping to maintain a controlled and efficient system.

Depending on the application, pneumatic seals come in a variety of shapes, sizes, and materials. FPM/Fluorocarbon rubber, nitrile, silicone, EPDM, and PTFE are some of the most popular materials used for pneumatic seals. However, overtime pneumatic seals can wear out or become damaged, compromising the pneumatic system's performance. In this blog, we will discuss some signs that indicate that pneumatic seals need to be replaced.

How to know if your pneumatic seal needs replacing?

Air Leakage:

One of the most obvious signs pneumatic seals need to be replaced is air leakage, either externally or internally. The most common areas where leaks can occur include joints, couplings, seals, and fittings, as well as hoses and areas which have worn packing. Air is usually audible and you may also notice a drop in system pressure.

Reduced performance:

Another sign that your pneumatic seal needs replacing is reduced performance. This could be due to seals no longer functioning as they should. Reduced performance could also cause a slower response time, or a loss of power from the system such as slow or uneven movement of the pneumatic cylinder or a decrease in the force it exerts.

Wear and Tear:

As a result of being exposed to harsh operating conditions such as high temperatures or chemicals, pneumatic seals are likely to wear and tear and can get damaged over time. Any pneumatic seals showing signs of damage, such as cracks, tears, or deformations, should always be replaced.

Contamination:

Contamination is another reason pneumatic seals fail. If the system is exposed to dirt, dust, or other debris, it can damage the seal and cause it to fail. If you notice any contamination, such as debris on the seal or in the system, it is important to clean it thoroughly and replace the seal.

Extreme Temperature:

The temperature range, of pneumatic seals are -4°F to +176°F, anything that is operating out of this range are susceptible to failure, when operating in extreme temperatures. This causes the seals to become brittle and crack. It is essential when choosing the appropriate medium that it is suitable to withstand the working temperature range of your pneumatic cylinder.

Age of the seals:

Pneumatic seals have a limited lifespan, and over time they will eventually need to be replaced. The lifespan of pneumatic seals can vary depending on a few factors, including the operating conditions of the system, the quality of the seals, and the level of maintenance the system receives. It is recommended that pneumatic seals be replaced every 2 to 3 years, or sooner if any of the above signs are present.

At FPE Seals, we offer a wide range of high-quality pneumatic seals and offer advice and guidance to help you find the part you need.

Unable to find what you need on our webstore? Please contact us and we will be happy to help source what you need.

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Question 29

5 Reasons Why a Hydraulic Cylinder Won’t Work

Accepted Answer

Hydraulic cylinder failure causes downtime in operations. This situation is not only inconvenient in terms of maintenance but also takes time to troubleshoot the problem.

Being aware of the most common issues related to operating hydraulic cylinders can help prevent problems from occurring and keep systems running smoothly. In this blog post, we will discuss some of the reasons why a hydraulic cylinder won't work.

Reasons Why Hydraulic Cylinders Stop Working:

1. A seal is worn or damaged

Seals gradually degrade over time and if not replaced hydraulic fluid leaks might occur. Due to insufficient fluid in the system, cylinders may become erratic in movement causing instability. Additionally, worn seals can cause misalignment between the cylinder rod and seal, causing the cylinder to operate inefficiently.

2. Lack of system pressure

To safeguard the hydraulic system, a hydraulic relief valve is used to regulate the pressure. One of the main reasons why a hydraulic cylinder won't work can be due to the system pressure or flow from the pump, being too low due to worn components. This can be solved by checking system pressure regularly.

3. The cylinder is damaged

A damaged cylinder can result in reduced system performance, loss of hydraulic pressure, fluid contamination, and fluid leakage, all of which can prevent it from working. Therefore, it is important to perform regular maintenance and inspections to ensure cylinders are in good working condition.

4. The cylinder rod is bent

A typical reason why a hydraulic cylinder is not working is due to a bent rod. Which has occurred due to its operation or abuse. Or if it is impacted by heavy objects or machinery, this can cause damage to the cylinder rod.

If you notice any signs of wear or deformation in the rod, it is important to replace it right away. This is not just to fix the problem, but also to make sure it does not cause any accidents or damage to your equipment.

5. Hose failure

The purpose of hydraulic hoses is to allow hydraulic fluid to flow from one component to another. Hoses are the means by which fluid is transferred freely and keeps vital parts of hydraulics systems moving. A damaged hose, results in leaking pressurised fluid. This can result in a loss of pressure in the hydraulic system, which can cause equipment to malfunction or stop working altogether. It is important to regularly inspect hydraulic hoses for signs of wear or damage.

In summary, the simplest way to avoid problems with a hydraulic cylinder is to perform regular inspection, and servicing, which can reduce the requirement for expensive repairs and downtime.
If you would like any advice on sourcing replacement metal parts or seals for your hydraulic ram, please contact our helpful and knowledgeable team today.

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Question 30

What are Bonded Washers?

Accepted Answer

Bonded Washers, also known as Dowty Seals or Bonded Seals, offer a powerful solution for achieving tight, leak-free connections in various applications. They are typically used in industries such as automotive, hydraulics, and pneumatics.

These seals are comprised of a metal washer and a rubber ring, which is bonded inside the diameter. The two components work together to create a dependable and leak-free connection. Bonded Washers are primarily designed to withstand high-pressure applications, making them a popular choice in hydraulic systems.

Properties and Materials:

The construction of Bonded Washers is simple yet effective. The metal washer, often made of steel or stainless steel, provides structural integrity, and prevents deformation under pressure. The rubber ring, typically made of nitrile rubber or other elastomeric materials, forms the sealing element. Nitrile rubber is widely used due to its excellent resistance to oil, fuel, and hydraulic fluids. However, different applications may require seals made from other elastomeric materials, such as silicone or fluorocarbon rubber, depending on the specific operational requirements.

Working Principle:

The working principle of Bonded Washers relies on a combination of compression and the elastomeric properties of the rubber ring. When the seal is tightened, the rubber ring compresses between the washer and the mating surface, creating a tight and secure connection. The rubber material provides resilience and elasticity, allowing it to adapt to slight variations in the mating surfaces, ensuring a dependable seal even under dynamic conditions.

Advantages of Bonded Washers:

Leakage Prevention: Bonded Washers offer exceptional sealing capabilities, preventing fluid leakage in high-pressure environments. Their robust design and secure connection help to maintain system integrity, reducing the risk of costly leaks and downtime.

Vibration Resistance: The rubber ring in Bonded Washers acts as a damping element, absorbing vibrations and reducing the chances of loosening or failure due to dynamic movements.

Easy Installation: Bonded Washers are simple to install, making them a time-saving solution for engineers. With just a washer and a rubber seal, they can be easily integrated into existing systems without requiring complex tools or techniques. Bonded Washers are flexible, and so can fit in a variety of devices.

Cost-Effective: These seals offer a cost-effective solution due to their durability and long service life. Their resistance to wear, tear, and degradation ensures that they can withstand demanding environments without frequent replacements, reducing maintenance costs over time.

FPE Seals stock and supply a comprehensive range of Bonded Washers that can be used to seal bolt heads and prevent leakage from hydraulic fittings or adaptors.

Can’t find what you are looking for? Get in touch with our knowledgeable team today for further advice and information about our products including a full range of hydraulic ram components.

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Question 31

A Guide to Seal Materials

Accepted Answer

Hydraulic seals are used in industrial applications, that prevent a fluid or gas from passing between different components of a cylinder, ensuring that the system operates efficiently and safely. However, not all seals are created equal, and different applications may require different types of seals. In this blog, we discuss the factors to consider when choosing the right seal, this is created in the appropriate material, to best suit your application.

Selecting The Right Seal:

When selecting a hydraulic seal, it's important to consider its material and design, to ensure that it works effectively, safely and reliably.

Temperature:

Temperature is one of the most important factors to consider when selecting seals. The temperature range of the seal must be compatible with the operating environment. If the seal is exposed to temperatures outside of its range, it can fail prematurely.

The temperature range of a seal is determined by the material it is made from. Different materials have different thermal properties. Some materials, such as rubber, are good at sealing at low temperatures, while other materials, such as metal, are better at sealing at high temperatures.

In addition to the operating temperature, the seal must also be able to withstand the temperature fluctuations that may occur in the environment. For example, a seal that is installed in a climate-controlled environment may not be able to withstand the extreme temperatures that can occur outdoors.

High Pressure:

Not all seals can withstand high pressure. Therefore, if you are looking to seal a high-pressure application, it is vital to select a seal in a material that can cope without deforming or breaking. The seal design must be able to create a tight seal without creating too much friction and the seal must be lubricated properly to prevent wear and tear.

Some of the most common types of seals used in high-pressure applications include:

O-rings: O-rings are made of a flexible material that can conform to the surface of the seal housing. They are available in a variety of materials, including rubber, nitrile, and fluorocarbon.

V-rings: V-rings are made of a stiffer material than O-rings and can withstand higher pressures. They are also available in a variety of materials, including rubber, nitrile, and fluorocarbon.

Piston seals: Piston seals are used to seal pistons in cylinders. They are made of a variety of materials, including rubber, nitrile, and fluorocarbon.

Fluid compatibility:

If the seal is not compatible with the fluid used in a hydraulic system, it can degrade the seal material prematurely, causing the seal to leak. When evaluating fluid compatibility numerous factors need to be considered including the chemical composition of the fluid, the operating temperature and pressure, and the seal material. Compatibility will vary dependant on the material type. For example, elastomers are generally compatible with a wide range of fluids, while plastics and metals are more limited in their compatibility.

Different Seal Materials:

Nitrile (NBR)

Properties: Nitrile seals have a good resistance to elongation at break, abrasion and compression set, but their flexibility suffers somewhat in the lower temperature range. Seals made from this material have a low resistance to ozone and must be stored carefully in most environments.

Temperature: Nitrile can withstand temperature range from -30°C to +100°C

Fluid Compatibility: The most common nitrile copolymer blend is the compound known as Buna-N. Possessing very good resistance to petroleum based hydraulic oils, Buna-N also works well with fuels such as diesel or gasoline.

PTFE

Properties: PTFE has chemical inertness, high heat resistance, low temperature flexibility, low running friction, and non-adhesive characteristics. Because of a lack of resilience (memory) in PTFE, an energizer is most often employed to obtain the desired fit.

Most PTFE seals, to retain their toughness and flexibility, are fortified with short glass fibres, bronze flashes, carbon graphite, or a combination of these fillers.

Temperature: PTFE can withstand temperatures to over 300°C but are often reduced by the filler or energizer employed.

Fluid Compatibility: PTFE seals are compatible with most chemicals, including acids, bases, and solvents.

Ethylene-Propylene (EPDM)

Properties: Ethylene-Propylene (EPDM) has good heat resistance, low compression set and good flexibility at low temperatures.

Temperature: Ethylene-Propylene temperature ranges between -45°C and +150°C .

Fluid Compatibility: Ethylene-Propylene can be used for sealing phosphate ester hydraulic fluids such as Skydrol but is not suitable for petroleum based fluid. Ethylene-Propylene is highly effective for use with steam, acetone, and dilute acids and bases. Specially compounded Ethylene-Propylene can be made suitable for automobile brake systems.

Polyurethane (AU)

Properties: Polyurethane is highly resistant to oil swell, ozone, oxidation, abrasion and has excellent cut resistance. Highly resilient, urethanes also have high tensile strength and elongation properties. Formulated of copolymers of ether or ester based urethanes, this material is used in a wide application of seals, wipers, backup rings, cushions, bumpers, and a myriad of other uses.

Temperature: Most urethane seals remain flexible and efficient in temperatures ranging between -54°C and +93°C with some able to withstand intermittent temperatures up to +135°C.

Fluid Compatibility: Polyurethane is compatible with hydraulic systems using petroleum based fluids.

Silicone (VMQ)

Properties: Silicone is an elastomer made from silicon, oxygen, hydrogen, and carbon. It has a high resistance to dry heat, ultraviolet light, and ozone. This material is not recommended for dynamic situations due to poor abrasion resistance and high friction characteristics.

Temperature: Silicone temperature ranges from -54°C to +204°C

Viton® - FPM / Viton® equivalent FKM

Properties: Viton® - FPM / Viton® equivalent FKM combines high temperature resistance with excellent chemical resistance. This material is not recommended for use in low temperatures or in aircraft hydraulic fluids.

Temperature: Viton® - FPM / Viton® equivalent FKM temperature ranges is -20° to +400° F.

Fluid Compatibility: Excellent for use with alcohol and aromatic fuels and highly resistant to ultraviolet light and ozone.

PolyEther Ether Ketone (PEEK)

Properties: PEEK has excellent strength, fatigue resistance and stability in high temperature environments, with a melting point around 343°C, and very good chemical resistance.

Temperature: PolyEther Ether Ketone (PEEK) recommended operating temperature is -54°C up to +260°C

Fluid Compatibility: PEEK is compatible with almost any of the solvents used in HPLC.

Hydrogenated Nitrile Butadiene Rubber (HNBR)

Properties: Hydrogenated Nitrile is also known as saturated Nitrile have excellent resistance to many modern fuels, resistance to high energy radiation & good abrasion resistance.

Temperature: Hydrogenated Nitrile Butadiene Rubber (HNBR) temperature ranges from -40°C to +150°C

Fluid Compatibility: HNBR is widely used in automotive and oil industries and maintains excellent resistance to motor oils, sour gas, amine/oil mixtures, oxidized fuels, and lubricating oils. HNBR is resistant to mineral oil-based hydraulic fluids, animal and vegetable fats, diesel fuel, ozone, sour gas, dilute acids, and bases.

Ultra high molecular-weight polyethylene (UHMWPE)

Properties: UHMWPE (Ultra High Molecular Weight Polyethylene) has very long molecular chains that helps to transfer load more effectively, strengthening intermolecular interactions. This results in a very tough material, with the highest impact strength of any thermoplastic presently made. It has very high abrasion resistance, shows zero water absorption, is self-lubricating and has a friction coefficient only slightly above most filled PTFE.

Temperature: Ultra high molecular-weight polyethylene (UHMWPE) recommended operating range is -200°C up to just +80°C

Fluid Compatibility: UHMWPE is stable in all hydraulic fluids, with high resistance to acids, bases, and aggressive media.

Selecting the right seal material is crucial to ensure the efficient and safe operation of machines, devices, and systems. Not sure what you are need? Get in touch with our knowledgeable team here at FPE Seals, who will discuss your requirements based on your application, and help you find the right seal for the job.

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Question 32

What are Static Seals?

Accepted Answer

Static seals are essential components used to prevent the leakage of fluids or gases between stationary surfaces. Unlike dynamic seals, which are used in applications involving relative motion between components, static seals remain fixed in place, creating a barrier between two non-moving surfaces. They are designed to maintain a reliable and leak-free interface under various operating conditions.

How Do Static Seals Work?

Static seals use various materials and designs to fill the gaps and imperfections between the mating surfaces. When compressed between the two surfaces, they form a barrier that stops fluids or gases from passing through. The effectiveness of the seal is determined by factors such as material properties, compression, and force.

Types Of Static Seals

o Gaskets: These are flat or profiled rings made from materials like rubber, cork, metal, or paper, commonly used to create a dependable, leak-free seal for applications such as engines, pumps, and pipe flanges.

o O-rings These are circular rings made from elastomers such as nitrile, silicone, or Viton. They are commonly used in hydraulic and pneumatic systems.

o Metal seals & Washers: These are typically made of copper, stainless steel, or aluminium, and are commonly used for high-temperature or high-pressure applications.

o Lip seals: These are expertly designed to seal around a shaft or rod securely to prevent fluid or gas leakages. They are commonly used in engines, gearboxes, and hydraulic systems.

o Diaphragms: These are flexible seals that move in response to changes in pressure or fluid flow. They are commonly used in pumps, valves, and regulators to ensure smooth operation.

o Bellows seals: These are accordion-like seals that can expand and contract to accommodate changes in temperature or pressure. They are commonly used in valves, pumps, and other high-pressure applications.

Factors To Consider When Choosing Static Seals

When choosing static seals, several factors need to be considered to ensure they meet the specific requirements of the application and provide effective sealing. Here are the key factors to consider:

o Material Compatibility: The seal material should be compatible with the fluids or gases it will meet. Different chemicals and environmental conditions can cause materials to degrade, swell, or become brittle, leading to seal failure.

o Temperature and Pressure: Static seals must be capable of withstanding the operating temperature and pressure of the application. Higher temperatures and pressures may require seal that can handle the heat and pressure without breaking down.

o Chemical compatibility: It is another key consideration when selecting static seals. Different materials are compatible with different types of chemicals, so it's important to choose a seal material that is resistant to the chemicals it will meet.

o Size and Shape: The seal must fit accurately within the designated space and match the required shape. Custom seals might be necessary for non-standard applications.

Benefits Of Using Static Seals

Static seals offer several benefits in various engineering and industrial applications. Here are some of the key benefits of using static seals:

o Leak Prevention: The primary function of static seals is to prevent the escape of fluids or gases, such as liquids, oils, gases, or chemicals, from one side of the seal to the other. By creating a reliable barrier, they help maintain system integrity and prevent contamination.

o Cost-Effectiveness: Static seals are typically simpler in design and easier to manufacture compared to dynamic seals, which require more complex mechanisms to accommodate relative motion. This simplicity often translates to lower production costs.

o Easy Installation: Since static seals do not require complex moving parts, their installation is often straightforward. They can be fitted in place with basic tools, reducing downtime during maintenance or repairs.

o Wide Range of Materials: Static seals can be made from various materials, such as rubber, silicone, metal, plastics, or composite materials. This versatility allows the seals to be tailored to specific applications, considering factors like temperature, pressure, chemical compatibility, and environmental conditions.

o Temperature and Pressure Resistance: Static seals are designed to withstand a wide range of temperatures and pressures, making them suitable for use in both low and high-pressure systems, as well as extreme temperature environments.

o Reduced Wear and Tear: Static seals experience minimal wear compared to dynamic seals because they are not subject to friction and movement. This leads to longer service life and less frequent replacement, resulting in cost savings over time.

If you require any further advice regarding Static Seals and their applications, then our knowledgeable team at FPE Seals would be happy to help.

We stock, source, and supply a fully range of Static Seals. Can’t find what you’re looking for? We can also manufacture the seals to your specification, in a full range of materials to meet your exact requirements.

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Question 33

What are Rotary Seals or Shaft Seals?

Accepted Answer

Rotary Seals also referred to as Shaft Seals, Oil Seals, or Lip Seals. Are designed to stop external contamination such as dirt, dust, water, and hazardous contaminants, from entering the moving parts, while retaining lubricant in the rotary applications.

The sealing effect is achieved by a garter spring which is normally used to ensure a constant force on the shaft. Rotary seals are used between rotating and static machinery components.

How Do Rotary Seals or Shaft Seals Work?

A rotary seal includes a sealing lip, a garter spring, and an external metal case. The sturdiness of the metal forms a rigidity and firm fix to the connecting components. The lip seal conducts the actual sealing function while the garter spring offers the required flexibility of movement. For vacuum applications rotary seals are designed differently and do not include a spring.

The basic design of the seal can be customised to suit specific requirements. These seals are extremely versatile and can be made of a variety of materials ranging from hard metals to plastic. The most common materials are steel, brass, silicone rubber, and EPDM.

Types Of Rotary Shaft Seals

There are different types of rotary shaft seals, each with its own specific design and materials. Some common types include:

1. Radial Lip Seals: These are the most common type of rotary seals. These seals are used in applications where the sealing surface is rotating relative to the housing. For low to high-speed applications, radial lip seals are designed in a wide variety of materials to best suit different fluids and temperature requirements.

2. V-Ring Seals: These are used for shafts that rotate in both directions. These seals are made of elastomer or rubber to prevent contamination from entering the shaft area and can handle high-speed applications.

3. Mechanical Seals: Mechanical seals are designed to seal against the rotating shaft using two flat surfaces. These seals can be made from a variety of materials including ceramic, carbon and metal and are typically used in high-pressure applications where a high degree of sealing is required.

4. Labyrinth Seals: Labyrinth seals are designed as a non-contact type of rotary seal which uses a series of grooves to create a curvy or tortuous path for the fluid or gas to flow through. These seals are effective at preventing contamination from entering the shaft area and are usually used in high-speed applications where there is a risk of fluid leakage.

5. Gland Packing Seals: They are typically used to seal a rotating shaft where the shaft passes through a stationary housing or casing, such as in a pump or a mixer. The packing material used in gland seals can be made of various materials such as graphite, PTFE, aramid fibre and carbon.

Choosing the Right Rotary Shaft Seal

For the proper functioning of applications, choosing the right rotary shaft seal is important. Several factors can affect the performance of rotary shaft seals, including:

1. Temperature: The performance and longevity of rotary shaft seal, can be affected by the operating temperature of the application, so choosing the right seal material is crucial.

2. Pressure: The pressure of the fluid being sealed can also affect the performance of rotary shaft seal, so it is essential that the seal chosen can withstand the pressure.

3. Speed: It is important to choose a seal that is designed for the appropriate speed range, so that the speed at which the shaft is rotating does not affect its performance.

4. Fluid type: Different fluids have different chemical properties that can affect the performance of the seal.

Benefits of Rotary Shaft Seals

1. Leakage Prevention: The primary function of a rotary shaft seal is to prevent leakage of fluids (such as oil, grease, or hydraulic fluid) from the housing or chamber where the shaft is rotating. By effectively sealing the gap between the rotating shaft and the stationary housing, these seals ensure that fluids stay contained within the system, reducing wastage and potential environmental hazards.

2. Contamination Protection: Rotary seals not only keep fluids in but also prevent external contaminants, such as dirt, dust, water, and other particles, from entering the system.

3. Friction Reduction: Using a well-designed rotary shaft seal can help minimise friction between the rotating shaft and the stationary housing and prevent wear on internal components, improving efficiency and reducing energy consumption.

4. Versatility and Reliability: Rotary seals come in various materials and designs suitable for different applications and operating conditions. They can be customised to manage a wide range of temperatures, pressures, speeds, and fluids.

Applications of Rotary Seals

1. Pumps: Rotary seals are used in pumps to prevent leakage of fluids such as water, oil, and chemicals.

2. Marine Applications: Used in applications such as propeller shafts, rudder shafts and thrusters to prevent leakage of seawater.

3. Food and Beverage Industry: Used in various food and beverage equipment to prevent contamination and ensure hygiene standards.

4. Pharmaceutical Industry: Used to prevent contamination and ensure product integrity.

If you require any further advice regarding Rotary Shaft Seals and their applications, our knowledgeable team at FPE Seals would be happy to help.

We stock, source, and supply a range of Rotary Seals. Can’t find what you’re looking for? We can also manufacture seals to your specification, in a full range of materials to meet your exact requirements.

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Question 34

How do Swivel Joints Work?

Accepted Answer

The Swivel Joint, also known as the Rotary Coupling, Rotary Union, Swivel Union, Rotorseal and Rotary Joint, plays a key role in controlling hydraulic circuits on an excavator.

Excavators use many hydraulic moving parts, to help manoeuvre the mechanical arm, reposition the bucket, adjust the digging angle, and control the tracks or wheels.

This requires different hydraulic circuits,

Upper: Mechanical arm elements
Lower: Tracks or wheels

The swivel connects the two together through a central shaft, to avoid a mass of twisted, tangled, or torn parts. Holes bored into the shaft allows fluid to flow through the swivel to its targeted cylinder, and as the centre shaft moves independently without restricting fluid flow, both upper and lower elements can move in different directions.

Typical design of a Swivel Joint

All swivels are not the same and will vary based on the number of mechanical elements on the upper moving section. Swivel joints can require anything from 3 to 10 seals to function correctly.

FPE Seals offer a wide range of competitively priced, OEM quality replacement seal kits for the repair and maintenance of swivel joints on excavators. Find out more here or contact the team to discuss your requirements.

Helpzone

Procedure: hydraulische en pneumatische afdichtingen meten

Hoe een hydraulische cilinder te monteren?

Hoe hydraulische afdichtingen worden gemaakt

Hoe een klierafdichting te plaatsen?

Hoe OP-afdichtingen op een dempingsklier passen?

Een composiet zuigerafdichting monteren

Hoe een 5-delige zuigerafdichting te monteren?

Procedure Online bestellen en registreren

Hoe u onze producten online kunt bestellen

How to: Source replacement seals and parts for a hydraulic cylinder.

How to: Use a Seal Clasper

How to: Source replacement seals and parts for agricultural machinery

How to: Use an O-Ring Material Tester

How to: Use an O-Ring chart

How to: Use an O-Ring Pick Set

How to: Source sealing solutions for food and beverage production

How to: Use Circlip Pliers

How to: Use Link Pin Dust Seal

How to: Use an O Ring PI Tape

How to: Use an O-Ring Measuring Cone

Catalogi

Technische Woordenlijst

Product Name Glossary

Compatibiliteit van Materialen

Installatie Tips

Afdichtingen Problemen

Swan Seals - Machined Seal Profiles

Kredietaanvraagformulier

Mini Excavator Seal Kits

O-Ring Housing Dimensions

Afdichtingen en cilindercomponenten

Hydraulische toepassingen

Helpzone

Procedure: hydraulische en pneumatische afdichtingen meten

Hoe een hydraulische cilinder te monteren?

Hoe hydraulische afdichtingen worden gemaakt

Hoe een klierafdichting te plaatsen?

Hoe OP-afdichtingen op een dempingsklier passen?

Een composiet zuigerafdichting monteren

Hoe een 5-delige zuigerafdichting te monteren?

Procedure Online bestellen en registreren

Hoe u onze producten online kunt bestellen

How to: Source replacement seals and parts for a hydraulic cylinder.

How to: Use a Seal Clasper

How to: Source replacement seals and parts for agricultural machinery

How to: Use an O-Ring Material Tester

How to: Use an O-Ring chart

How to: Use an O-Ring Pick Set

How to: Source sealing solutions for food and beverage production

How to: Use Circlip Pliers

How to: Use Link Pin Dust Seal

How to: Use an O Ring PI Tape

How to: Use an O-Ring Measuring Cone

Catalogi

Technische Woordenlijst

Product Name Glossary

Compatibiliteit van Materialen

Installatie Tips

Afdichtingen Problemen

Swan Seals - Machined Seal Profiles

Kredietaanvraagformulier

Mini Excavator Seal Kits

O-Ring Housing Dimensions

Afdichtingen en cilindercomponenten

Hydraulische toepassingen

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