Reciprocating pump for an implantable medication dosage device
First Claim
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1. A reciprocating pump for an implantable medicaton dosage device comprising:
- a housing have a fluid conveying passage with a piston consistig at least in part of magnetically attractive material and having a planar end face disposed in said passage, said passage terminating in an outlet;
first magnetic means for moving said piston in said passage through an output stroke to force fluid through said outlet;
second magnetic means for moving said piston in said passage through a return stroke;
a valve disposed at said outlet of said passage having a moveable element having a portion consisting of magnetic material;
a permanent magnet spring system disposed to act on said magnetic material portion of said moveable element for normally forcing said moveable element against said outlet to block fluid flow through said passage;
said moveable element of said valve having a planar surface disposed for pressing tightly adjacent said end face of said piston for at least a portion of said output stroke, at least one of said surface of said moveable element or said end face of said piston having a non-planar region; and
said piston assuming a rest position in said housing at an end of said return stroke with a distance between said end face of said piston and said surface, and said piston and said passage being cooperatively dimensioned so that said output stroke is longer than said distance, thereby lifting said moveable element away from said outlet during said output stroke.
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Abstract
A reciprocating pump suitable for use in an implantable medication dosage device has a piston movable in a chamber connected to a medication reservoir, the chamber having an output closable by a check valve. The check valve includes a movable element which is acted upon by a biasing system to urge the moveable element in a direction to close the check valve. The moveable element has a sealing surface against which an end face of the piston presses with tight adjacency as the piston moves to an extreme position during its output stroke.
227 Citations
11 Claims
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1. A reciprocating pump for an implantable medicaton dosage device comprising:
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a housing have a fluid conveying passage with a piston consistig at least in part of magnetically attractive material and having a planar end face disposed in said passage, said passage terminating in an outlet; first magnetic means for moving said piston in said passage through an output stroke to force fluid through said outlet; second magnetic means for moving said piston in said passage through a return stroke; a valve disposed at said outlet of said passage having a moveable element having a portion consisting of magnetic material; a permanent magnet spring system disposed to act on said magnetic material portion of said moveable element for normally forcing said moveable element against said outlet to block fluid flow through said passage; said moveable element of said valve having a planar surface disposed for pressing tightly adjacent said end face of said piston for at least a portion of said output stroke, at least one of said surface of said moveable element or said end face of said piston having a non-planar region; and said piston assuming a rest position in said housing at an end of said return stroke with a distance between said end face of said piston and said surface, and said piston and said passage being cooperatively dimensioned so that said output stroke is longer than said distance, thereby lifting said moveable element away from said outlet during said output stroke. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification