Standards:globe valve
Design and Manufacture: Cast steel globe valve to BS 1873
and ASME B16.34;Forged steel globe valve to API 602.
Inspection and Test: API 598.
End flange dimension: ASME B16.5.
BW end dimension: ASME B16.25.
Socket-weld dimension: ASME B16.11.
Face to face and end to end: ASME B16.10.
Pressure-temperature ratings: ASME B16.34.
The features of globe valve
Bolted Bonnet; Outside Screw and Yoke; Rising stems; Metallic seating surfaces.
Body and Bonnet Connection
The body and bonnet of Class150~Class900 check valves are usually with studs and nuts. And the body and bonnet of Class1500~Class2500 check valves are usually of pressure seal design.
Gasket of Cover Flange
Stainless steel + flexible graphite wounded gasket is used for Class150 and Class300 globe valve. Stainless steel + flexible graphite wounded gasket is used for Class600, and ring joint gasket is also optional for Class600. Ring joint gasket is used for Class900 globe valve. Pressurized seal design is used for Class 1500~Class2500 globe valve.
Actuation
Hand wheel, impact hand wheel & gear box is usually used for globe valve actuation. Chain wheel and electric actuator can be also used for globe valve actuation if being requested by the customers.
Packing Seal
Molded flexible graphite is used for packing material. PTFEor combined packing material can be also used if being equested by the customer. The internal surface of thestuffing box, of which area is contacted with the packing, isof excellent finish (Ra 3.2μm). The stem surface, contactingwith the packing, should be rolled and pressed after beingprecisely machined, so as to reach to the high finish and com-pactness (Ra 0.8μm) and ensure the reliable tightness of the stem area.
Back Seating Design
All our globe valves have the back seat design. In most cases, the carbon steel globe valve is fitted with a renewable back seat. For stainless steel globe valve, the back seat ismachined directly in the bonnet or is machined after welding. When the globe valve is at fully open position, the sealing of
the back seat can be very reliable. However, as per the requirement of API, it is not advisable to add or change packing by the mean of back seating whenthe valve is pressure containing.
Seat
For carbon steel globe valve, the seat is usually forged steel.The sealing surface of the seat is spray welded with hard alloy specified by the customer. Renewable threaded seat is used forNPS≤10 globe valve, and welded on seat can be also optional if being requested by the customer. Welded on seat is used for NPS ≥ 12 carbon steel globe valves. For stainless steel globe valve, integral seat is usually adopted, or to weld hard alloy directly integrally. Threaded or welded on seat is also optionalfor stainless steel globe valve if being requested by the customer.
Stem Design
The stem is of integral forged design. The minimum diameter of the stem shall per the standard requirement.
Stem Nut
Usually, the stem nut is copper alloy. It is also can be made of ASTM A439 D2 if being requested by the customer. For large sized globe valve, rolling bearing is fitted at the two sides of stem nut in order to minimize the open and close torque of the globe valve.
Special Globe Valve
Besides the common globe valves, we also makes cryogenic globe valve,bellow sealed globe valve,Jacketed globe valve, etc.