Check valves need to be installed in the following situations:
(1) The pump itself does not allow reverse rotation due to its structure.
(2) Centrifugal pump with head ≥25m.
(3) The process does not allow the medium to flow back to the suction side of the pump.
The following situations do not require a check valve:
(1) For transfer pumps whose medium contains solid particles and is prone to crystallization.
(2) A pump with a foot valve on the suction side.
(3) The pump itself has no restriction on reverse rotation and the centrifugal pump has a lift <25m.
(4) The rotating part of the pump is equipped with flywheel effect components, such as enlarged couplings, flywheel components, etc.
Installation of pump outlet check valve
(1) The straight-through lift check valve should be installed on the horizontal pipeline; the vertical lift check valve must be installed on the vertical pipeline, and the medium flows from bottom to top.
(2) Swing check valves are generally installed on horizontal pipelines: check valves with a diameter of DN~80mm can also be installed on vertical or upward-inclined pipelines.
(3) Since the check valve is easily damaged, the check valve should be installed close to the pump outlet, and a cut-off valve (generally a gate valve or ball valve) should be installed above the check valve to facilitate maintenance.
(4) In order to facilitate pressure relief before disassembly of the check valve, if the check valve itself does not have a purge valve, a purge valve for pressure relief should be installed between the check valve and the cut-off valve.
