Piston seals ultimately help to maintain a strong contact seal between a piston and a cylinder bore.
Available in a wide range of materials, in this post, we look at the hydraulic piston seal in more detail, how it works, and where it can be used.
Piston seal definition
Piston seals provide a tight seal between a cylinder bore and the piston.
Preventing hydraulic fluids and air from leaking and escaping, the way in which piston seals work allows the cylinder itself to extend and retract in a smooth operation.
Dynamic by nature, piston seals are available in various styles, sizes, and materials, all of which should be carefully considered when selecting the right seal for your application.
Taking into account the design of the cylinder, the application materials, and the operating conditions.
What is a piston seal?
A seal that must be able to withstand high pressure and dynamic movement, a piston seal is used to prevent leaks from occurring.
These types of seals and gaskets can be single-acting, i.e., pressure acting on one side only, or double-acting, i.e., pressure acting on both sides.
Single-acting pistons help to contain pressure and prevent leaks on one side of the piston only. The seal helps to move the piston along the cylinder in a single action. Maximum effort can be applied to moving the piston along the bore of the cylinder to help retain pressure.
Note: Single-acting piston seals can be CNC machined to bespoke sizes.
Double-acting piston seals – this seal contains everything on both sides of the piston. Driving the hydraulic or pneumatic ram in and out, or maintaining a controlled position, double-acting piston seals have a symmetrical profile.
There is a vast range of double-acting seals available, some of which include:
- MPV seals – suitable for heavy-duty applications, this industrial sealing solution is constructed with a polyurethane slide ring and nitrile rubber.
- DPV seals – similar to MPV seals, but this type of seal fits o-ring dash number housings.
- LPV seals – suitable for light to medium duty applications.
- CPV – the same as LPV seals, but again fits o-ring dash number housings.
Single acting seals available include:
- UNP seals – a u-cup profile that is suitable when using two seals back-to-back. Suitable for medium-duty applications.
Customised piston seals are also available, and you can speak with a member of the SSP team to find out more and have your questions answered.
Note: Backup and guide rings can be used in conjunction with piston seals to reinforce the seal and hold it in the correct position.
The importance of a piston seal
We can’t emphasise this particular point enough – piston seals are invaluable in mechanical and industrial systems, ensuring the efficient and safe functioning of cylinders and pistons.
The benefits of these seals include durability, efficiency, and performance, with piston seals available as:
Rod seals – help to prevent fluid from moving along the rod. Effectively working in the push and pull directions – suitable for double-acting cylinders.
Scraper – helps to prevent impurities from entering the cylinder.
Guide elements help minimise metal contact between the piston and the cylinder.
When we look at how a piston seal works, ultimately, it works by containing pressure on one side of the piston.
The piston seal can be driven either hydraulically or pneumatically to prevent leaks past the piston.
Meeting the requirements for low friction, piston seals are compact and involve simple installation as they are placed inside the cylinder head and against the cylinder bore.
Benefits of piston seals
- Provide a great sealing solution
- Resistant to wear
- Offer excellent extrusion properties
- Can handle extreme temperatures
- Available as single or double-acting seals
- A range of materials and sizes is available.
Available in:
PTFE – chemical resistant, low friction, resistance against varying temperatures, and offers electrical insulation.
Nitrile – durable, resistant to wear, oil and grease, and certain chemicals.
Rubber – versatile, durable, resistant to water and abrasion.
Thermoplastic polyurethane – flexible, abrasion-resistant, and can withstand impact at low temperatures.
Polyamide – offers high strength and elasticity.
Two of the major benefits of this type of gasket sealing are that it is available in a range of different designs to suit various applications, and the anti-extrusion ring in piston seals helps to prevent gap extrusion, providing a more robust sealing solution.
Piston seal application
We use piston seals primarily in:
- Industrial machinery
- Hydraulic presses
- Automotive components
- Agricultural machinery
- Medical equipment
- Aviation
- And more.
Gasket and seals
If you’re looking for a precision gasket and seal, we’re the experts to turn to.
Designing and manufacturing high-quality seals for a range of industry sectors and diverse applications, we use laser precision and state-of-the-art technology to eradicate guesswork and ensure a high-quality, industry-suitable seal.
At Specialist Sealing Products, we can help you choose the right piston seal for your application.
With our extensive range and knowledgeable staff, contact us today to find out more.
