Centrifugal pump gas tie phenomenon: When the pump housing air, due to the density of the air density is much smaller than the liquid generated less centrifugal force. Thus, the tank above the liquid level and the pump inlet pressure difference is not enough to liquid storage tank pressure into the pump, that is, centrifugal pump without self-suction capacity, so that the centrifugal pump can not deliver liquid, a phenomenon called "gas tied phenomenon". In order to fill the pump with liquid, a bottom valve with strainer is usually installed at the bottom of the suction pipe. The bottom valve is a check valve. The strainer prevents solid matter from entering the pump to damage the impeller or impede the normal operation of the pump.
