Check valve refers to the flow of the media itself and automatically open and close the disc, to prevent the media flow back valve, also known as check valve, one-way valve, counter current valve, and back pressure valve. Check valve is a kind of automatic valve, its main function is to prevent the medium back flow, prevent the pump and drive motor reverse, as well as the discharge of container medium.
1: Check valves should be installed on equipment, Fittings and Piping to prevent media counter-current.
2: Check valve popular suitable for clean medium.
3: In general, lift check valves should be used in nominal diameter 50mm horizontal pipelines.
4: Straight-through Lift check valve can be only be installed in horizontal pipeline.
5: Bottom valve widely use in pump inlet pipeline, and medium flow from bottom to Top.
6:Lift check valve is better than Swing Check type sealing, Fluid resistance, horizontal should be installed in the horizontal pipeline, vertical installed in the vertical pipeline.
7: Swing Check valve install position is free, it can be installed in horizontal,vertical or inclined pipeline, such as installed in vertical pipeline, medium flow from down to up.
8: Swing check valve not good at to made into small size, which can produce high working pressure, nominal pressure can reach 42Mpa and diameter also can be very large, maximum more than 2000mm. According to material of Shell and seal, it can be applied to different working medium and temperature range. Medium including Water, Steam, Gas, Corrosive Medium, Oil, Medicine etc. And working temperature range between -196~800℃;
9: Swing Check valve suitable for Low-pressure large diameter and installation occasions are limited;
10: Butterfly Check Valve installation position is not have limited which can installed in the horizontal pipeline, also can installed in the vertical or inclined pipeline.
Check Valve Structure Principle
Swing Check valves allow virtually no obstruction of fluid pressure when fully open, so the pressure drop through the valve is relatively small.
The disc of lift check valve is located on the body& seat sealing surfaces. In addition to the valve disc can be free to lift, the rest of the globe valve, the pressure of the fluid valve disc from the seat sealing surface, media back flow causes the disc to fall back to the seat, and cut off the flow. Refer to working condition, the disc can be an all-metal construction or it can be plated on the disc frame in the form of rubber pad or rubber ring. Like globe valve the fluid through the life check valve channel is narrow, so the lift check valve pressure drop than swing check valve, and swing check valve flow is limited by few.
1: The disc of Swing check valve is disc-shaped,rotating around the shaft of the valve seat channel for rotary movement due to valve channel into streamline, flow resistance is small then the lifting check valve. Swing check valve is divided into single, Double and Half three types and different forms are mainly divided according to valve diameter, the purpose is to prevent the medium to stop flowing or reverse flow, weaken the hydraulic impact.
2: Lift Check Valve disc slides along the vertical center line of the valve body. Lift check valve can only be installed on horizontal pipes. The shape of lift check valve is the same as globe valve. Therefore its fluid resistance coefficient is relatively large. Its structure is similar to that of the globe valve, and the valve body&disc are also same as well. The direction of the medium inlet and outlet channels is same as that of the valve seat channel, and its flow resistance is smaller than that of the straight- through type.
