How does the Jamesbury Lip Seal design work?
Jamesbury’s lip seal deisgn uses a completely different sealing principle than a typical “Jam” seat. A “jam” seat is simply jammed between the body and the ball and uses the compression of assembly to provide the forces necessary to create a seal. This results in high operating torques and thermal expansion problems. With Jamesbury’s Lip seal design, the ball is cradled between the two seats but the seal is created by elastic (spring-like) movement of the seat’s lip rather than compression of the complete seat. The movement of the lip is limited by the heel. Once the ball has moved a pre-determined amount against the lip due to pressure or thermal expansion, the ball then contacts the heel and significantly reduces any subsequent movement. The benefits of this design include cavity relief without a relief hole or upstream pressure. Also, it reduces the operating torque requirements for the valve. Finally, the design copes much better with thermal expansion than a typical “jam” seat.
