Working principle of the Grady ring

• Static Pre-Sealing (System Without Pressure)

• The O-ring is pre-compressed within the rectangular groove, generating continuous radial elasticity.

• This elasticity acts as an initial driving force, pressing the sealing lip of the wear-resistant slip ring (usually made of PTFE) tightly against the cylinder wall, forming the first basic seal to prevent static leakage.

• Dynamic Pressure Activation (System Pressurization)

• When the hydraulic system generates pressure, the pressurized medium (such as hydraulic oil) enters the sealing groove.

• The pressure acts on the side of the O-ring, pushing it towards the groove and significantly increasing its compressive force on the slip ring.

• This amplified force is transmitted to the slip ring, causing its sealing lip to adhere to the cylinder wall with greater clamping force. The higher the pressure, the greater the clamping force, thus achieving a "self-sealing" effect. This is key to its ability to withstand high pressure.

• Low-Friction Motion

• During reciprocating motion, the low-friction coefficient PTFE slip ring is the only component that experiences sliding friction with the cylinder wall.

• The O-ring merely remains within the groove to provide elasticity and does not participate in sliding, thus avoiding the high resistance and wear caused by direct rubber friction.

• The inherent lubricity of the PTFE material and the oil film retention capability of the structural design ensure smooth motion and no creep.