Check Valve Reverse flow is prevented
Structure and selection of check valves and control valves
The role of valves in the type of valve that prevents dielectric flow is to only allow the medium to flow in one direction and prevent direction flow. Normally this valve is operated automatically, and under a fluid pressure that flows in one direction, the disc opens; When the fluid is in the opposite direction, the self - overlapping disc of the fluid pressure and the disc ACTS on the seat, thus cutting off the flow. Check valves belong to this type of valve, including swing check and lift check valves. The swing check valve has a hinge mechanism, and a gate like valve is free to rest on the inclined seat surface. In order to ensure that each disc to seat the appropriate location, in valve design hinge agencies, so that the disc with enough space of a swing, and real, comprehensive, and the valve seat contact. The disc can be made entirely of metal and can be embedded in the metal with leather, rubber or synthetic coverage depending on the performance requirements. When the swing check valve is fully open, the fluid pressure is almost impervious, so the pressure drop through the valve is relatively small. The valve flap of the lift check valve is located on the seat seal on the valve body. In addition to this check valve can be freely valve movements, like the rest of the cut-off valve, fluid pressure from the valve seat sealing surface lift, medium return led to the disc back to seat, and cut off the flow. Depending on the conditions of use, the disc may be an all-metal structure or in the form of a rubber pad or rubber ring on the disc rack. Like a cut-off valve, fluid through the lift check valve channel is narrow, so the lift check valve through the pressure drop than the swing check valves are bigger, and swing check valves are very few restrictions.
According to the adjustment medium parameter, the valve is used in the production process. In order to make the pressure of the medium and the flow parameters conform to the requirements of the technological process, the adjustment mechanism should be adjusted by the adjusting mechanism. The main operating principle of the regulating mechanism is to adjust the circulation area between the valve disc and the disc and the seat to achieve the purpose of regulating the above parameters. Belong to this type of valve are collectively referred to as control valves, which are divided into depending on the medium power driven itself is called self drive type control valve, such as pressure reducing valve, regulator valve and so on, all that lead up to driving (such as electricity, compressed air and fluid dynamics) called him drive type control valve, such as electric control valve, pneumatic control valve and hydraulic regulator, etc.
