Soon Seng PolySeal - oil seals, hydraulic seals, pneumatic seals, mechanical seals
Sonn Seng Poly Seal


A U-Cup is used to seal hydraulic fluid (hydraulic U-Cup seal) or air (pneumatic U-Cup seal). It creates the necessary pressure for the hydraulic and pneumatic power systems to work. It is designed to ensure that pressurised fluid/air does not leak across the cylinder head as the system pressure pushes the piston down or up the cylinder bore.

The choice of U-Cup is decided by the way in which a cylinder operates. For a single-acting cylinder, in which the sealing dynamic pressure is from one side (unidirectional), it is best to choose a seal designed for single-acting to provide optimum sealing. In the case of a double-acting cylinder, in which the sealing dynamic pressure is from both sides (bidirectional), the sealing is best achieved by using a double-acting seal. If two single-acting U-Cup is used in a double-acting cylinder, the seal may breakdown due to the fact that a very high pressure can be trapped between the single-acting seals.

The sealing lips on the U-Cup are molded to form a symmetrical profile. It has a very slight radius to prevent all the lubricant on a shaft or housing to be wiped off, which may cause a considerable amount of wear on the seal and hence, early seal failure. The U-cup also does not rely on initial compression to seal; hence it is an excellent seal to be used in applications that require low breakaway pressure.

There are numerous applications for this type of seal, for examples, construction and off-road vehicles, backhoes, front-loaders, tractors, cranes, bull dozers and forklifts.

A U-Cup can be designed to be used with integrated or separate back-up rings and guide rings to further improve the pressure rating of a hydraulic system.

Home    |    About Us    |    Products    |    Vendors    |    Contact Us   
21,Birch Road, Singapore 219888   Tel: +65-6298 8011   Fax: +65-6296 1583
Business Reg no. 43690100E, GST Reg no. M8-8002081-1
Copyright © 2015 [Soon Seng Poly Seal]