Metal bearing surfaces of the spool design

The seat ring metal bearing surfaces match each other, but the contact angle is slightly different. Under normal circumstances, the spool having a larger taper angle than the seat ring. This annular not match to ensure a narrow point of contact is the overall operation of the axial force is only passed to a small portion of the seat, and thus the possibility of the most tightly closed metal-to-metal contact. In most structures, the manual shut-off valve seat ring is screwed into the valve body. In the limited space requirements with the tool to rotate the seat ring. With threaded seat also has certain disadvantages: First, in corrosive or harsh conditions, thread corrosion, making removal difficult, the second, the timing of the codes in the pair between the valve body and the valve seat, the need additional grinding

steam solenoid valves

The procedure to obtain the desired valve closed. Third, in the presence of vibration, the seat ring in the closed position can not be cock maintain, because the seat ring may eventually loose through the seat gasket leak or the valve seat surface does not.
Some cut-off valve bubbling close Close, metal to metal seal is unattainable. To accomplish these, can be embedded in the seat ring elastomer. In this case, the seat ring is a two-part structure embedded in the elastomer, i.e., between the two halves. The surface of the metal cock pressed against the valve seat ring soft bearing surfaces, such as the surface of the valve plug and seat ring is concentric, will be able to double tight shut down of. Some manufacturers are also embedded within the valve body and the elastomer to obtain the same effect.

pneumatic hand valve