Inhalation height and the following factors: First, the saturated liquid vapor pressure of the liquid saturated liquid vapor pressure is greater, the inhalation height is smaller. Second, the liquid density The greater the density of the liquid, the smaller the inhalation height. Third, the local atmospheric pressure The greater the local atmospheric pressure, the greater the inhalation height. Fourth, the liquid temperature The higher the temperature, the greater the saturated vapor pressure, inhalation height is smaller. Fifth, the diameter of the tube The larger the diameter of the tube, the smaller the resistance loss, the greater the inhalation height. Sixth, the liquid flow rate The higher the liquid flow rate, the loss of resistance and kinetic energy head the greater the smaller the inhalation height. Seven, the pump inlet check valve weight or spring size of the size of the inlet check valve weight or spring force greater, the top of the liquid valve to open the greater the required head, so the suction height is smaller.