Hydraulic and pneumatic seals
Hydraulic and pneumatic seals seal under pressure, on linear rather than rotating surfaces. In a cylinder the piston seal holds pressure, the rod seal stops leakage, and the wiper keeps dirt out — the three are designed together, because when one fails the others follow quickly.
Types and variants
The distinct designs that sit under this category.
Piston seals
Hold pressure between the two cylinder chambers, in single and double acting forms.
Rod seals
The main element stopping oil from escaping the cylinder.
Wipers and scrapers
Scrape off the dust, water and ice the rod carries back in.
Guide bands and back-up rings
Prevent metal-to-metal contact and stop the seal extruding into the gap.
Where it is used
The applications this category most often serves.
- Excavator boom, bucket and steering cylinders
- Presses and injection moulding machines
- Hydraulics in steel, cement and paper plants
- Pneumatic cylinders and valves
- Lifting and elevating platforms
What we ask when selecting
What we need in order to find the right part. You do not need all of it — we can work out the rest together.
- Working and peak pressure
- This decides whether a back-up ring is needed.
- Rod or bore diameter and groove size
- The groove matters as much as the seal — the right seal leaks in the wrong groove.
- Speed and stroke
- Short frequent strokes and long slow ones call for different profiles.
- Fluid and temperature
- Mineral oil, water-glycol and HFC fluids each mean a different material.
Other categories in this group
Send us the designation or the dimensions — we will find the match.
A code you cannot find in the catalogue, a faded marking on an old bearing, or just the dimensions — any of the three is enough. The wrong bearing costs more than a late one.