Design of disc
Gate valves with NPS>/2 are of wedge flexible gate. Gate valves with NPS＜2 are of wedge solid gate.
Body and bonnet connection
The body and bonnet of Class 150 - 900 gate valves are usually connected with studs and nuts. And the body and bonnet of Class 1500 - 2500 gate valves are usually of pressurized seal design.
Gasket of cover flange
Carbon steel or stainless flexible steel graphite combined gasket is used for Class 150 gate valve; Stainless flexible steel graphite wounded gasket is used for Class 300 gate valve; Stainless flexible steel graphite wounded gasket is used for Class 600 gate valve, and ring joint gasket is also optional for Class 600 gate valve; Ring joint gasket is used for Class 900 gate valve; Pressurized seal design is used Class 1500-Class 2500 gate valve.
Actuation
Hand wheel and gear box is usually used for gate valve actuation. Chain wheel and electric actuator can also be used for gate valve actuation if being requested by the customers.
Seat
For carbon steel gate valve, the seat is usually made of forged steel. The sealing surface of the seat is spray welded with hard alloy specified by the customer. Welded seat is used for NPS1/2 - 2. Renewable, threaded seat is used for NPS≤8 gate valves. And welded seat can be also optional for the NPS≤8 gate valves if being requested by the customer. Welded seat is used for NPS＞8 carbon steel gate valves. For stainless steel gate valve, integral seat is usually adopted, or to weld integrally hard alloy directly. Threaded or welded seat is also optional for stainless steel gate valve if it is being requested by the customer. If the customer has any other request about the seat, please kindly advice before placing the order.
Stem design
The stem is of integral forged design. It is one piece T-head construction.
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.
Back seating design
All of our gate valves have the back seating design. In most cases, the carbon steel gate valve is fitted with a renewable back seat. For stainless steel gate valve, the back seat is machined directly in the bonnet or is machined after welding.
Stem nut
Usually, the stem nut is made of copper alloy. It is also can be made of ASTM A439 D2 if being requested by the customer.
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