Pump export check valve selection, installation and protection measures
1.Pump export check valve selection
Generally, the pumping station project for pump export check valve selection, should follow the following principles,
Smaller diameter of pump export pipeline, namely the DN < 50, should choose the movements of check valve.
The pump export pipe diameter of pipe and experiment.it 50 DN should choose swing check valves
Swing check valves can be installed in horizontal or vertical. Swing check valve disc rotates around the axis movement, the fluid resistance generally less than movements of check valve, it is suitable for large diameter, installation position is unlimited, usually installed in horizontal pipe, it applies with larger diameter. According to the number of disc can be divided into single swing, double disc swing and disc swing 3 kinds. Single swing check valves are generally use the occasion with medium caliber. Large diameter pipeline choose single swing check valves, to reduce the water hammer pressure, had better use of the water hammer pressure to reduce hydraulic slowly-closing check valves. Double disc swing check valves are used with large diameter pipeline. Double disc to clip a swing check valve structure, light weight, it is a kind of fast check valve, Many disc swing check valves are used with large diameter pipeline.
2.Check valve, pump export of installation
1 swing check valves are usually installed in horizontal pipe runs for caliber DN ~ 80mm check valves, they can also be installed in vertical or upward raked in the pipeline.
(2) movements of check valve should be installed in a horizontal pipe, Vertical movements of check valve must be installed in a vertical line, medium for bottom-up flow.
3 because of check valve damage easily, therefore, should be close to pump export installation check valve, check valve upside sets cut-off valve (generally with the ball or gate), convenient maintenance.
4 for ease of check valve, pressure, remove the front for check valve is put on the net, valve and check valve between the relief valve installs the cut clean valve with put.
3 to prevent hydraulic shock to check the sealing surface damage and protective measures
Check valve setting, rose to prevent backflow, avoid materials from liquid pump impeller. But just check valve itself, undeserved, can cause water produces disc and seat to hit, suddenly and check valve seal. Therefore, we should adopt some protective measures.
1 set to pump export > DN 80mm swing check valves, should adopt horizontal installation to abate disc and seat back.
2, for pump export check valve size of the pipeline, the 150mm experiment.it DN should check valve, prevent valve by-passes before setting up on high pressure, before the check valve seal of damage.
3 and the pump discharge pipe start and finish high pressure pipeline, don't allow the bypass, set to take the following measures.
1 set to replace bypass valve valve. Its function is similar with bypass valve. It is set in check valve, when the water near the exit to pressure, will be released in order to prevent the pressure of water to heighten of damage.
2 sets of air cushion tank or inert gases. The setting in check valve, when the water near the exit, through the buffer tank with pressure gas compressed to ease the pressure of the water.
General import and export flow pump Settings:
Import isolating valve - : filter
Export check - export isolation valve
Import and export bypass valve
Export valve (relief valve)
Export pipelines regulator, etc
Isolation valve are used gate valves \check valve \ plug valves, etc
