Selection Requirements Of Check Valve

- May 31, 2018-

  1. Many comprehensive factors should be considered when selecting the check valve type:

(1) . the opening pressure of the check valve is related to the sealing performance when the check valve is closed. If the sealing performance is good when the check valve is closed, the opening pressure will be large, otherwise it will be small.

(2) . the opening pressure is generally greater than the local head loss of normal flow after opening.

(3) , quick closing silencing check valve and damping slow closing check valve have the function of weakening the stop water hammer, but their mechanism of weakening the stop water hammer is different. Quick closing silencing check valve is generally used for small caliber water pump, and damping slow closing check valve is generally used for large caliber water pump.

(4) . when the water flow stops, the disc or core of the check valve shall be able to close automatically under the action of gravity or spring force. Generally speaking, horizontal lift check valve, damping slow closing check valve and multi-function valve can only be installed on horizontal pipe. Except vertical lift check valve, other check valves can be installed on horizontal pipe or vertical pipe with water flow direction from bottom to top. For the riser with water flow direction from top to bottom, check valve shall not be installed, and the valve disc shall not be closed by itself, so as to play a non-return role.


2. The selection of the valve type of the check valve shall be determined according to the installation position of the check valve, the water pressure in front of the valve, the sealing performance requirements after closing and the size of the water hammer caused by closing, etc., which shall meet the following requirements:

(1) For the parts with small water pressure in front of the valve, swing, ball and edge check valves should be selected.

(2) . for the parts with tight sealing performance after closing, the check valve with closed spring should be selected.

(3) . where it is required to weaken and close water hammer, quick closing silencing check valve or slow closing check valve with damping device should be selected.

(4) The disc or core of check valve shall be able to close automatically under the action of gravity or spring force.

(5) The minimum pressure of the pipe network or the minimum water level of the water tank shall be able to automatically open the check valve.