Pumps – Motor driven – Electric or magnetic motor
Reexamination Certificate
1999-06-29
2001-02-27
Walberg, Teresa (Department: 3742)
Pumps
Motor driven
Electric or magnetic motor
C417S417000
Reexamination Certificate
active
06193477
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to the art of electromagnetically operated fluid pumps, and more particularly to a new and improved electromagnetic pump which operates at extremely low power.
One area of use of the present invention is implantable drug delivery systems, although the principles of the present invention can be variously applied. The principal requirements for a pump in such applications are low power drain, since the pump must be driven by an implanted battery, and compatibility with the drug being pumped. Another important requirement is that the pump be capable of operating with bubbles present in the liquid being pumped. A related consideration is that the bubble pumping capability provided in the pump not give rise to inaccuracy caused by inertia of the fluid stream. Such inertial effect is a result of the momentum of the fluid stream being capable of maintaining motion of the stream for some time after completion of the pump piston stroke, and the fluid volume delivered as a result of the stroke is thereby increased. A further pump design consideration is providing a relatively small displacement pump which pumps bubbles in a manner equivalent to that of a larger displacement pump.
It would, therefore, be highly desirable to provide an electromagnetically operated pump which is safe, reliable, small in size, light in weight, which operates without excessive demand on the available energy supply, which is compatible with drugs or similar liquids to be pumped, which is capable of operating with bubbles present in the liquid being pumped, wherein the inertial effect on pump accuracy is reduced, and wherein the bubble pumping capability is not reduced by a reduction in pump displacement.
SUMMARY OF THE INVENTION
It is, therefore, a primary object of this invention to provide a new and improved electromagnetically operated pump.
It is a more particular object of this invention to provide such a pump which operates at extremely low power levels.
It is a further object of this invention to provide such a pump which is compatible with the fluid being pumped.
It is further object of this invention to provide such a pump which is electronically and magnetically efficient.
It is a further object of this invention to provide such a pump which is capable of operating with bubbles present in the fluid being pumped.
It is a further object of this invention to provide such a pump which reduces the fluid inertial effect on pump accuracy.
It is a more particular object of this invention to provide such a pump which is small in size, light in weight and efficient and reliable in operation.
It is a further object of this invention to provide such a pump wherein the displacement can be reduced without reducing the bubble pumping capability of the pump.
The present invention provides an electromagnetic pump comprising a housing having a fluid receiving chamber in communication with an inlet, a fluid pumping chamber in fluid communication with an outlet, check valve means operatively associated with the fluid receiving chamber for allowing fluid flow in a direction from the inlet toward the outlet and blocking fluid flow in a direction from the outlet to the inlet, electromagnet means carried by the housing located external to the fluid chambers thereof, and barrier means in the form of a thin diaphragm of fluid impermeable material which hermetically isolates the electromagnet from the fluid chambers. An armature movable in the housing has a pole portion located for magnetic attraction by the electromagnet means and has a piston portion to force fluid out of the chambers and through the pump outlet. The armature piston portion is movably supported in the pump housing and located on the inlet side of an armature plunger. The armature is moved from a rest position through a forward pumping stroke when attracted by the electromagnet means to force fluid from the receiving chamber through the outlet, and the armature is moved by biasing means in an opposite direction through a return stroke back to the rest position. There is also provided controlled means for providing a bypass path for bubbles and fluid around the armature piston portion between the fluid pumping chamber and the fluid receiving chamber only during the return stroke of the armature.
The fluid inertial effect is reduced by means for providing an orifice in the path of fluid flow from the pump outlet and by means in the bypass path for providing an orifice for fluid flow in that path, the outlet and bypass orifices being provided either individually or in combination depending upon the fluid flow characteristics of the system of which the pump is a part. An accumulator means in the fluid flow path between the pump outlet and a catheter leading away from the pump alleviates inertial and viscous effects arising from the catheter. The armature pole portion has a fluid-contacting section of material which is compatible with and corrosion resistant to the fluid, and in one aspect is a body of magnetic material within a titanium enclosure and in another aspect is a body of chrome-molybdenum-iron alloy. The check valve means and inlet are so arranged that the pump displacement can be reduced without reducing the bubble pumping capability of the pump.
REFERENCES:
patent: 5797733 (1998-08-01), Falk et al.
patent: 5915929 (1999-06-01), Falk et al.
Brown W. Richard
Falk Theodore J.
Frenz, Jr. Norbert W.
Gillies Douglas K.
Konopa Raymond S.
Fastovsky L
Hodgson Russ Andrews Woods & Goodyear LLP
Walberg Teresa
Wilson Greatbatch Ltd.
LandOfFree
Low power electromagnetic pump does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Low power electromagnetic pump, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Low power electromagnetic pump will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2575898