The bottom valve of English as the FOOT VALVE, in fact, is a kind of check valve to prevent reverse flow of water plays the role. 
 The end of the valve material can be divided into the end of the valve and metal end of the plastic valve can also be divided into the common end of the valve end of the valve and the backwash water. The bottom valve of the domestic brand quality is generally poor, such as Mifengbuyan, existence of the leakage problem, so the system is difficult to achieve automatic control, each irrigation to the suction tube, very troublesome. 
 Bottom valve uses 
 The bottom valve is an energy-saving valve, usually installed at the bottom of the pump underwater suction. Limit the return water of the liquid in the pump tube, plays not only into the function of the valve cover there is a lot of water supplies and strengthen tendons, played a hard block, mainly used in pumping the pipeline. watercourses and supporting role. caliber single lobe, double valve, Orange Peel type flange and threaded connections. bottom valve is estimated by the valve, the valve bonnet See the figure below water water into the valve from the valve cover, bushings, seals and other parts composed of open water in the fluid under pressure, the valve flap, the pressure within the outlet pipe when the show is stopped quickly close the valve flap, The liquid will not pour back to the water, played the role of the smooth pumping and saving water energy loss. 
 1, in order to prevent the media from countercurrent, equipment, installations and pipelines should be installed non-return valve; 
 2, check valve generally applicable to pure media, should not be used to contain solid particles and the viscosity of the medium; 
 3, the general in nominal vertical lift check valve should be selected by a horizontal pipe 50mm; 
 Lift performance specifications 
 Nominal pressure: PN0.25MPa 
 Nominal diameter: DN15 ~ DN350 
 Applicable medium: water, oil, and non-corrosive media 
 Implementation of standards: Q/12 NJ3583-2001 
 Test Standard: GB/T13927-1992