U-ring with Y-shaped ring is slightly different in shape, U-ring lip length,the bottom thickness is same as lip, Or the bottom slightly larger than lip. Like with Y sealing ring,the U sealing is working by two lips, so the Y sealing ring also named U sealing ring sometimes.

　　The follow figure show a combined U sealing ring, it is consist of a U-shaped clip fabric elastic rubber and hard rubber fabric retainer clip. U-shaped lip ring is divided into two parts, the Intermediate bosses play a role in support ring, to prevent bite of gap of the lip. U sealing ring work closely with retaining ring groove, not easy to squeeze into the gap. there is a small amount of deformation of block under the action of high pressure fluid. Compensation for sealing,So the sealing is very good. This seal structure is compact, small axial size, the stability of the movement is good, and anti-distortion, good rigidity, Working pressure up to 40MPa, The maximum speed of the reciprocating motion 0.5m / s, suitable for piston seal of hydraulic cylinder of heavy machinery.

　　Combined U-ring must be properly design installed size in order to obtain the desired size and seal life. The design may refer to FIG. 2 and Table 1.

　　FIG. 2 combined U sealing ring 1-Usealing ring;2-closing ring

　　FIG.2　Combined u-shaped seal structure

　　Table 1. Combined u-shaped ring sealing device size series