Patent ID: 6796777
Filing Date: 2004-09-28
Classification: A61M,F04B,Y10T

Abstract:
An electromagnetic pump comprising:a) a housing defining an interior fluid containing region comprising a fluid receiving chamber and a fluid output chamber in fluid communication therewith, an inlet in fluid communication with the receiving chamber and an outlet in fluid communication with the output chamber; b) check valve means operatively associated with the fluid containing region for allowing fluid flow in a direction from the inlet through the outlet and blocking fluid flow in a direction from the outlet through the inlet; c) electromagnet means carried by the housing and located external to the fluid containing region defined in the housing; d) an armature positioned in the fluid containing region of the housing, the armature comprising a pole portion having a diameter for attraction to the electromagnet means and comprising a one piece plunger portion comprising a plurality of shaft portions and a head portion directly adjacent the pole portion and the head portion having a diameter substantially the same as the diameter of the pole portion, and the shaft portions having diameters and wherein the shaft portions are ordered such that the diameters of the shaft portions only increase in a direction toward the head portion and wherein the head portion diameter is greater than the diameters of the shaft portions, the one piece plunger portion and pole portion joined together and the pole portion located for magnetic attraction by the electromagnet means; e) the armature being movably supported in the housing for movement from a rest position through a forward pumping stroke when the pole portion is attracted by the electromagnet to force fluid from the output chamber through the outlet and for movement in an opposite direction through a return stroke back to the rest position; and f) means defining a magnetic circuit including the electromagnet means and the armature and a gap between the pole portion of the armature and the electromagnet means for moving the armature toward the electromagnet means to close the gap in response to electrical energization of the electromagnet means.