What is a lift check valve?
Lift check valve refers to the valve that automatically opens and closes the valve disc depending on the flow of the medium itself to prevent the backflow of the medium. It is also known as check valve, one-way valve, reverse flow valve and back pressure valve. The check valve belongs to an automatic valve, which is mainly used to prevent medium backflow, reverse rotation of pump and driving motor, and discharge of container medium. The check valve can also be used on the pipeline to supply the auxiliary system in which the pressure may rise above the system pressure. Check valves can be mainly divided into swing check valves (rotating according to the center of gravity) and lift check valves (moving along the axis).
Structure of lift check valve
Lift check valve is a valve to prevent the backflow of pipeline medium. It is mainly composed of valve body, valve seat, valve disc, valve cover and other related parts. The lift check valve is equipped with a spring to ensure that the valve disc is always in a state of dynamic balance under the action of the spring. The valve can maintain balanced operation regardless of the medium pressure at the inlet end of the valve.
Working principle of lift check valve
The lift check valve disc is provided with a guide rod, which can rise and fall freely in the guide hole of the valve cover. When the pipeline medium flows in the specified direction (from left to right), and the pressure below the valve disc exceeds the pressure above it, push the valve disc to rise along the center line of the guide hole of the valve cover, and the valve will open automatically, so as to make the medium flow; If the fluid flows from right to left, that is, when flowing backward, the pressure above the valve disc is greater than the pressure below it. The pressure difference between the upper and lower pressure and the self weight of the valve disc press the valve disc on the valve seat, so that the medium cannot pass through, that is, the fluid cannot flow backward; And the greater the pipeline fluid pressure, the tighter the sealing surface is, the better the sealing effect is.
The valve seat sealing surface of the lift check valve can be overlaid, or made into a valve seat sealing ring and then expanded or threaded to the valve body; When the valve body is made of stainless steel, the sealing surface can also be processed directly on the valve body. The sealing surface of the valve disc can be directly processed on the valve disc, or processed after surfacing or welded on the valve disc with the inner and outer periphery of the sealing ring. The straight through lift check valve can only be installed on the pipeline in balance, and the center line of the valve disc is vertical to the horizontal plane, while the vertical lift check valve is not subject to this restriction.
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