Hydraulic Cylinder Seal


The design of hydraulic cylinder seals has to factor in the highly demanding operating environment where hydraulic equipment and heavy machineries are subjected to. The product line includes piston seals, rod seals, back-up rings, o-rings and wiper seals.

Gmors Rubber Industrial Co., Ltd. designs and manufactures hydraulic sealing parts in materials optimised for specific applications, ensuring a high level of compatibility with corrosive hydraulic fluids and an extended service life.

Hydraulic Seals and Pneumatic seals 

Hydraulic seals are found in many hydraulic powered equipment, where it is necessary to seal the fluid inside of a cylinder. Basically, hydraulic seals can be of two types, static and dynamic. The material that goes into the manufacturing of hydraulic seals can of rubber, polyurethane or PTFE. The correct choice of material is determined by the service pressure, chemical compatibility of fluid to be sealed and temperature.  

Static Seals: Hydraulic seals of the static variety are seated within a groove and movement is not expected. Static seals perform like a gasket, and is kept compressed by applied pressure from tightening of bolts. 

Dynamic Seals: Hydraulic seals of the dynamic variety include rod seals, where movement is expected between the contact of the inner diameter of the seal with the rod of shaft of the cylinder. 

Piston Seal: Piston seals are subject to different demands depending on the application. The are a number of factors that has to be considered in the selection, including the type of hydraulic fluid, the rate of application cycle and speed, service temperature and pressure. A controlled amount fluid leakage for piston seal is not unacceptable because such fluid serves the function of lubricating the piston seal during motion. 

Gmors manufactures both single and double-acting piston seals. Design or selection of seal must allow for a small measure of fluid leakage pass the contact area between the elastomeric seal and the surface of the cylinder to act as lubrication. The level of friction between the seal and the surface of the cylinder tube can be determined to avoid excessive friction resulting in increased wear, and reduced service life of the seal. 

Rod Seal: In hydraulic cylinders, an important seal component is the rod seal, which functions as fluid containment. Unlike piston seals where small amount of leakage serves as lubrication, leakage would be unacceptable for rod seals because loss of pressurized fluid would affect equipment performance. 

Pneumatic Seals: Pneumatic seals do not operate under the same high pressure as hydraulic seals. The are found in applications that require rotary as well as reciprocating motions. Applications include pneumatic cylinders and pneumatic valves. Speed of operation of pneumatic seals can be high, but pressure typically stays within 150 psi. In contrast, hydraulic seals are capable of operating pressures in excess of 10,000 psi. 

Rotary seals: Single acting, one axial directional sealing application which is made up of a single pneumatic seal. 

Reciprocating seals: A double acting sealing application making use of two seals, one for each direction. The design of reciprocating seals is more complicated. 

A complete system of sealing for pneumatic equipment that includes piston seals, rod seals, cushion seals and valve seals is available in a variety of material grades. Material types include FKM, NBR, polyurethane and more. 

Gmors manufactures hydraulic and pneumatic seals according to your specified profiles in any dimensions and material grades. Consult our material specialists with details of your application and we will be glad to offer our recommendations.