Pressure Seal bonnet Swing Check valve는 body와 bonnet사이에 gasket를 넣어 body의 내압에 의해 bonnet를 밀어 올려서누설을 방지하는 고온고압 발전소에 가장 많이 사용되고 있다. Bolt로 체결하지 않는구조로 Top Flange가 없고 bolted bonnet 밸브보다 면간거리가 짧아 중량이 가볍고 주로 맞대기 용접으로 배관에 부착한다.Swing Check Valve의 용도는 유체의 역류방지가 목적이다.
■ HINGE PIN
The hinge pin is inserted into the valve body to achieve pressure seal construction.
The cover material is a steel forging identical to the body to insure high dependability. the cover construction has a perfect body-cover tightness and ease of dismantling and reassembly are ensured.
The arm is of a steel material identical to the body. Larger sized valves are provided with a hinge bushing to reduce friction and to prevent galling.
■ SEAT RING
The Stellite 6 surface of the seat ring is integrally applied to the body by means of welding in all valve sizes. Perfect mating with the DISC surfaces attained by a lapping finish applied to the seating.
The disc has a sufficient seating surface area which is ground and lapped to a mirror finish. It is of one-piece construction and is heat treated to deliver the required mechanical properties and hardness.
The cylindrically shaped valve body prevents distortion or undue stress under extreme working conditions. Padding is also provided to achieve a sound cast structure in the critical areas. the wall Thickness is greater than, or in accordance with, API, ANSI and ASME requirements. the area contacting the pressure seal gasket has a stainless steel 18/8 inlay to eliminate corrosion or wire drawing. the close tolerances of the inside diameter of this area are attained by accurate machining and honning finish.