Views:20 Author:Site Editor Publish Time: 2020-11-11 Origin:Site
The butterfly plate is driven by the valve stem, if it is turned 90°, it can complete one opening and closing. Changing the deflection angle of the butterfly plate can control the flow of the medium.
Butterfly valve action
Butterfly valves are suitable for pipelines that transport various corrosive and non-corrosive fluid media in such engineering systems as generators, coal gas, natural gas, liquefied petroleum gas, city gas, hot and cold air, chemical smelting, power generation, environmental protection, and building water supply and drainage. To adjust and cut off the flow of the medium.
Pressure test method
The strength test of pneumatic butterfly valve is the same as that of globe valve. The sealing performance test of the butterfly valve should introduce the test medium from the end of the medium flow, the butterfly plate should be opened, the other end should be closed, and the injection pressure should reach the specified value.
After checking that there is no leakage in the packing and other seals, close the butterfly plate, open the other end, and check that there is no leakage at the seal of the butterfly plate. The butterfly valve used to adjust the flow can not be tested for sealing performance.
The opening and closing part of the gate valve is a gate. The movement direction of the gate is perpendicular to the direction of the fluid. The gate valve can only be fully opened and fully closed, but cannot be adjusted or throttled.
The closing principle of the gate valve is that the sealing surface of the gate and the sealing surface of the valve seat are highly smooth, flat and consistent. They are mutually attached to prevent the medium from flowing through, and rely on the shape of the top mold, spring or gate to enhance the sealing effect.
Gate valve function
The gate valve mainly plays a cutting role in the pipeline. It has low fluid resistance and is easy to open and close. It can be used in the case of two-way flow of the medium. It has no directionality. When fully opened, the sealing surface is not easy to be eroded. The structure length is short. Valves, and suitable for large valves.
Pressure test method
The strength test of gate valve is the same as that of globe valve. There are two methods for the sealing test of the gate valve.
The gate is opened to increase the pressure in the valve to the specified value; then the gate is closed, and the gate valve is immediately taken out to check whether there is leakage at the seals on both sides of the gate or directly inject the test medium into the plug on the valve cover to the specified value. Check the seals on both sides of the gate. The above method is called intermediate pressure test. This method is not suitable for sealing test on gate valves with nominal diameter below DN32mm.
Another method is to open the gate to increase the test pressure of the valve to the specified value; then close the gate and open the blind plate at one end to check whether the sealing surface leaks. Reverse the head and repeat the above test until it is qualified.
Pneumatic gate valve packing and gasket sealing test should be carried out before the gate sealing test.
Company Name: Tianjin Tangfa Watts Valve Co., Ltd.
Contact Person: Mr. jack wang (General Manager)
+86 22 66224148
+86 22 25291233
RM 501-2, NO.1 Building,Tianhe technical Area
Binhai New area,Tinajin City,China