The features of globe valve
Bolted Bonnet; Outside Screw and Yoke; Rising stem; Metallic seating surfaces.
Body and Bonnet Connection
The body and bonnet of Class 150 ~ Class 900 globe valves are usually with studs and nuts. And the body and bonnet of Class 1500 - Class 2500 globe valves are usually of pressure seal design.
Gasket of Cover Flange
Stainless steel + flexible graphite wounded gasket is used for Class 150 and Class 300 globe valve. Stainless steel + flexible graphite wounded gasket is used for Class 600, and ring joint gasket is also optional for Class 600. Ring joint gasket is used for Class 900 Globe valve. Pressure seal Design is used for Class 1500 - Class 2500 globe valve.
Back Seating Design
All our globe valves have the back seating design. In most cases, the carbon steel globe valve is fitted with a renewable back seat. For stainless steel globe valve, the back seat is machined directly in the bonnet or is machined after welding. When the globe valve s 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 when the 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 for NPS ≤ 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 optional for 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.
Actuation
Hand wheel, impact hand wheel & gear box is usually used for globe valve actuation. Hand 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. PTFE or combined packing material can be also used if being requested by the customer. The internal surface of the stuffing box, of which area is contacted with the packing, is of excellent finish (Ra 3.2 μ m). The stem surface, contacting with the packing, should be rolled and pressed after being precisely machined, so as to reach to the high finish and compactness (Ra 0.8 μ m) and ensure the reliable tightness of the stem area.
Belleville Spring Loaded Packing Impacting System
If being requested by the customer, the Belleville spring loaded packing impacting can be adopted for enhancing the durability and reliability of the packing seal.
Stem Nut
Usually, the stem nut is made of copper alloy, it is also can be made of ASTMA439 D2 if being requested by the customer. For large sized gate valves (NPS 10 for Class 150, NPS 8 for Class 300, NPS 6 for Class 600, NPS 5 for Class 900), rolling bearing is fitted at the two sides of the stem nut in order to minimize the open and close torque of the gate valve.
Special Globe Valve
Besides the common globe valves, we also make cryogenic globe valve, bellow sealed globe valve, Jacketed globe valve, etc.
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