The sealing principle of butterfly check valve:
The structure of the butterfly check valve is similar to that of a butterfly valve, and its sealing principle is similar to that of a butterfly valve. There are two types of butterfly check valves, one is single plate and the other is double plate. The sealing principle of the single-plate butterfly check valve is closer to that of the butterfly valve. When the butterfly valve is closed, it relies on the torque transmitted by the valve stem to the butterfly plate, while the single-plate butterfly check valve is completed by the eccentric torque generated by the reverse flow of the medium. When the single-plate butterfly check valve is opened, it relies on the downstream flow of the medium, overcomes the torque generated by the weight of the butterfly plate, and opens the butterfly plate to achieve the purpose of opening; when the pump is stopped, there is no forward flow of the medium, and it depends on the butterfly plate. The torque generated by its own weight closes the butterfly check valve. Then rely on the pressure when the medium returns to produce the sealing specific pressure to achieve the sealing. At this time, it should be noted that the butterfly check valve with higher pressure should have a wider sealing surface width, and the butterfly check valve with lower pressure should have a narrower sealing surface. In short, it is necessary to ensure that the actual specific pressure on the sealing surface is greater than the necessary specific pressure to ensure the sealing. And it should be less than the allowable specific pressure allowed by the material, which can not only ensure effective sealing, but also be safe. For the double-plate butterfly check valve, it is opened by the pressure of the medium backflow to overcome the torque of the spring, and closed by the torsion torque generated by the torsion spring, and then sealed by the sealing ratio generated by the pressure of the medium backflow. The double-plate butterfly check valve is the same as the single-plate butterfly check valve. When the working pressure of the medium is high, the width of the sealing surface should be designed to be wider, and the width of the sealing surface should be designed to be narrower when the working pressure of the medium is low. some. Only in this way can the sealing performance be guaranteed without damaging the sealing surface.
Structural features of butterfly check valve:
The butterfly check valve has a relatively simple structure. According to the pipeline conditions, it can be installed vertically or horizontally, and its installation method is relatively flexible. And because it can be made into a pair of clips, it has smaller dimensions and lighter weight. It has less fluid resistance and less water hammer pressure. However, due to structural reasons, the butterfly check valve cannot be made into a high working pressure, and is only suitable for medium and low pressure occasions.
Post time: Sep-27-2022