Bolted bonnet Globe valve는 body와 bonnet 사이에 gasket를 넣어bolt로 체결하여 body와 bonnet사이의 누설을 방지하는 구조로 석유화학용 밸브에 가장 많이 사용되고 있다.
Globe Valve의 용도는 유량이나 압력을 조절하는 목적으로 주로 사용된다.
■ YOKE SLEEVE
The standard material of the Yoke Sleeve is Nodular Ni-resist D2 with over a 1150℃(2100℉) dissolution point in conformity 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 bonnet is integral or separate with the yoke and is the same material as the body. The body-bonnet flange drilling is spot-faced to exactly meet stud bolt nuts. The back seat bushing in the bonnet guarantees that the packing can be replaced even when the valve is fully opened. The stem packing dimensions of the stuffing box are in accordance with API Std. specifications.
The heat-treated stems of one-piece construction insure adequate mechanical properties and surface hardness. Friction at the time of opening and shutting is reduced to a minimum friction to accurate machining and lapping. The round finished surface of the stem head helps to achieve point contact with the inside of the disc housing to eliminate friction.
■ SEAT RING
The shoulder seated type seat ring is welded or screwed into body. The seating surface is finished by lapping. The seat ring is forged and heat-treated to deliver the best mechanical properties and required hardness. The difference in hardness between the seats and disc conforms to API Std. specifications.
The disc of our globe valves is a loose disc and can freely revolve around the stem. This prevents friction and galling with the seating surface when the valve is shut. The disc is furnished with a conical seating surface that has been ground and lapped to a mirror finish. It is of one-piece construction, and forged and heat-treated to deliver the required mechanical properties and hardness.
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. Port and seat passage dimensions conform to ANSI B16.5 Pipe Fitting. The screw-in type seat ring is standard to allow interchangeability. the standard body-bonnet joint is male-female, and the flange is round for all valves. Accurate machining insures perfect coaxiality of the valve ends and seat ring in addition to exact perpendicularity of the body-bonnet flanges.