Lift check valve:
A check valve with a disc sliding along the vertical center line of the valve body, a lift check valve can only be installed on a horizontal pipe, and a ball can be used on a high pressure small diameter check valve. The body shape of the lift check valve is the same as that of the globe valve (which can be used in common with the globe valve), so its fluid resistance coefficient is larger. Its structure is similar to the globe valve, and the valve body and disc are the same as the globe valve. The upper part of the valve disc and the lower part of the valve cover are processed with a guide sleeve, and the valve disc guide can be lifted and lifted freely in the valve disc guide. When the medium flows along, the valve disc is opened by the thrust of the medium, and when the medium stops flowing, the valve disc lands on the valve seat by self-drooping to prevent the reverse flow of the medium. The direction of the medium inlet and outlet channel of the straight-through lift check valve is perpendicular to the direction of the seat channel; Vertical lift check valve, the medium inlet and outlet channel direction is the same as the seat channel direction, the flow resistance is smaller than the straight-through type.
Swing check valve:
The disc of the swing check valve is disk-shaped and rotates around the shaft of the valve seat channel. Because the channel in the valve is in a flow line, the flow resistance is smaller than that of the lift check valve. It is suitable for large diameter occasions where the flow rate is low and the flow does not change often, but it is not suitable for pulsating flow, and its sealing performance is not as good as the lift. Swing check valve is divided into single lobe, double lobe and half type three, these three forms are mainly divided according to the valve diameter, the purpose is to prevent the medium to stop the flow or reverse flow, weaken the hydraulic impact.
Butterfly Swing Check Valve:
Butterfly check valve and butterfly valve structure is similar, the main difference is: butterfly valve as a cut-off valve must be driven by external forces, and butterfly check valve is an automatic valve, do not need to drive mechanism. When the medium stops flowing or backflows, the disc rotates to the seat by its own weight and the action of the backflow medium. This type of check valve can be used on both horizontal and vertical tubes, and is usually installed in a clip-on type. Under the action of fluid pressure, the two valves overcome the spring force to rotate around the pin, and the state of opening is somewhat like a sign. The inlet and outlet of the valve should leave some straight pipe section, because the valve disc must have a certain rotation space.
