Electromagnetic plunger pump

摘要

An electromagnetic plunger pump of the reciprocating type including a vent valve means which allows only air bubbles in the pump to pass therethrough. This vent valve means is provided in a pressure adjusting plunger fitted in a pressure adjusting cylinder for reciprocating motion. The vent valve means comprises a vent valve rod which is fitted in a through-hole of the pressure adjusting plunger so as to form a passage about the vent valve rod, and a vent valve body which is normally energized by a spring in the direction away from a vent valve seat at a forward end of the pressure adjusting plunger to provide a clearance between the vent valve body and the vent valve seat. This clearance is such that it allows the air bubbles to pass therethrough, while it does not allow a liquid under pressure having a viscosity to pass therethrough with the result that the vent valve means is closed by such liquid under pressure. The air bubbles and the excess liquid under pressure from the pressure adjusting mechanism are returned to a storage tank.