Bolted bonnet Gate valve는 body와 bonnet사이에 gasket를 넣어 bolt로 체결하여 body와 bonnet사이의 누설을 방지하는 구조로 석유확용 밸브에 가장 많이 사용되고 있다. Gate Valve의 용도는 Disc를 완전히 열거나 닫아서 사용하는것으로 유체를 차단하는 것이 주된 용도이다. 기본적으로 긴급하거나 빈번한 개폐 조작을 중요시 하지 않는 배관에 사용된다
■ YOKE SLEEVE
The upper portion of the Yoke Sleeve is hexagonally tapered to fix the handwheel. The standard material of the Yoke Sleeve is Nodular Ni-resist D2 with over 1150℃(2100℉) dissolution point accordance with API Std. specifications.
The body-bonnet bolts are manufactured in accordance with API Std. 600 specifications. The nuts also strictly conform with ANSI B 1.1 The stud-bolt nuts, hexagonal, rigid and hot-forged, bear material notation as well as do the bolt nuts made according to ANSI B18.2.2
The machined forged stem comes with a T-shape head, which connects the slot of the wedge. The spherically shaped contacting surface of the head gives greater strength and durability. The stem dimensions are in accordance with API Std. 600 specifications. The heat treated stem delivers adequate mechanical properties as well as excellent surface hardness. Further, opening/shutting friction is minimized by accurate machining and lapping.
■ SEAT RING
Bottom seated type seat rings are welded or screwed into the body. The seating surface is finished by lapping. the are forgings that have been heat treated to delived the best mechanical properties and required hardness. The difference in hardness between seats and wedge is in accordance with API specifications.
■ FLEXIBLE WEDGE
The standard disc of our valves is a one-piece flexible wedge. Slots are machined on both sides of the wedge to allow it to travel correctly in the integrally cast body guides. The wedge seating surfaces have been accurately machined, grind and lapped to a mirror finish to prevent leakage and eliminate galling.
The cast steel body is designed to insure a wall thickness which is grater at any point than the minimum specified by API Std. 600. Special care has been taken with the design of h\the Class 150 valve body so that the elliptically shaped center section is free from intensified stresses in the critical area. The body of above Class 300 are made circular in shape as much as possible to minimize distortion even under extreme operating conditions. Inlet and outlet port dimensions conform with ANSI B16.5 Pipe Fitting. The welded-in type seat ring is standard to insure interchangeability. Except for Class 150, the standard body-bonnet joint is male and female.