● STANDARD FEATURES OF WEDGE GATE VALVES

1. Main Adopt Standards● 

(1) Design and manufacture as per API 600 , API 602, ASME B16.34. 

(2) Flanged ends dimension as per ASME B 16.5(NPS2～24),

      ASME B16.47(NPS ＞24) , 

      MSS-SP-44(NPS 22). 

(3) Welded ends dimension as per ASME B16.11.

(4) Threaded ends dimension as per ASME B1.20.1. (5) End-to-end dimension as per ASME B16.10.

(6) Pressure test as per API 598. 

2. Connection between body and bonnet

(1) For Cl150～Cl900: bolted bonnet construction;

(2) For Cl1500～Cl2500: pressure seal bonnet construction.

3. Driving design

Valve drive usually has manual or gear operation, according to customer requirements can choose pneumatic, electric, etc.

4. Stem packing

We usually uses expanded graphite to make stem packing. Based on customer requirements, PTFE or other materials can also be used. The surface area of the stuffing box in contact with the packing has an accuracy of Ra 3.2um. The surface of the valve stem in contact with the packing is finely ground by a grinder, its surface finish is (Ra 0.8 um) to ensure effective sealing between the valve stem and the packing.

5. Back seat design 

All gate valves of our company are equipped with upper sealing structure. For stainless steel gate valves, the upper seal is directly processed on the valve cover. As for the carbon steel gate valve, the upper seal is a separate structure, which is fitted on the valve cover through threads. This ensures that the sealing performance of the upper seal will be very reliable when the valve is in the fully open position. According to the requirements of API 600, a sealing structure is provided between the valve stem and the bonnet. However, it cannot be understood as a recommendation and suggestion by the manufacturer that the packing can be added or replaced by the upper seal when the valve is under pressure.

6.Seats 

For carbon steel gate valves, forged steel is usually used for the valve seat. The seat sealing surface can be welded with alloy steel or hard alloy according to customer requirements.

For stainless steel gate valves, an integral valve seat is usually used, or it is directly welded with hard alloy.

7. Stem

The stem is adopted with an integral forged steel design. The minimum size should meet the requirements of API600 standard. The stem is connected to the gate by a T-shaped structure, and the strength of the connection is greater than the trapezoidal thread part of the stem.

8. Yoke

Generally, for NPS2 to NPS8 gate valves, the yoke should be integral type, for gate valve size above NPS 10", the yoke should be split type.

9. Stem Nut

Generally, the stem nut is made of aluminum bronze alloy. It can also be manufactured in accordance with ASTM A439 D2 according to user requirements.

10. Optional Material

According to customer requirements, our company will select the material suitable for the corresponding medium according to the different working conditions.

● STANDARD MATERIALS FOR CAST STEEL WEDGE GATE VALVES 

Note: Other materials can be selected based on customer requirements.

● STANDARD MATERIALS FOR FORGED STEEL WEDGE GATE VALVES

Note: Other materials can be selected based on customer requirements.