This type equips automatic air vent mechanism. An air vent valve builtin pump chamber enables reliable air venting. Also equipped manual air vent valve enables easy pressure release in discharge piping. Gaseous liquid such as sodium hypochlorite or hydrogen peroxide can be injected without gas locking.
Air which comes from suction port goes to the connection adapter through pump head. Because pump discharge side is pressurized, air goes to the automatic air vent valve which the pressure load is lower than pump discharge side, and goes out little by little together with liquid.
Once the pump gets out of locked air condition, it returns to normal operation to discharge the liquid. A ittle bit of liquid is discharged from automatic bleed valve, too.