US 5,318,521 AGranted

Dosing device for the controlled delivery of a liquid

AssigneeSiemens Aktiengesellschaft

InventorBruno Slettenmark

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Abstract

In a dosing device of the type suitable for human implantation for delivering a liquid medicament, a piston of a pump is accelerated against a detent by energization of an electromagnetic actuation system, with the electromagnetic actuation system being controlled so that it is de-energized slightly before the piston reaches the detent, with the inertia of the piston carrying the piston against the detent to complete the piston stroke. By shortening the amount of time during which the electromagnetic actuation system is energized, energy is saved. Control of the electromagnetic actuation system is undertaken by identifying a nominal stroke time for the piston by detecting the impact of the piston against the detent, and calculating an on time for the electromagnetic actuation system which is so short that the impact of the piston against the detent can still be just barely detected.

Claims22

Dependent claims

A dosing device for use with a liquid-containing reservoir, for controlled delivery of liquid from said reservoir to a delivery site, said dosing device comprising:

a piston pump having a piston in a cylinder housing having a detent, said piston being movable in a stroke between a quiescent position and a position in contact with said detent;
electromagnetic actuation means for causing said piston to move toward said detent from said quiescent position;
,
detector means for generating a signal upon impact of said piston with said detent;
control means for supplying a turn-on signal and a turn-off signal to said electromagnetic actuation means;
and
evaluation means, connected to said control means and supplied with said signal from said detector means, for setting the .length of an on-time duration following a turn-on signal and for instructing said control means to generate said turn-off signal after the expiration of said on-time duration by setting said on-time duration to a length shorter than the time required for said piston to move from said quiescent position to said detent given fault-free operation, and for lengthening said on-time duration in the absence of a signal from said detector means for a first predetermined number of strokes within a second predetermined number of strokes.

4 more elements

A method for operating a dosing device for controlling delivery of a liquid through said dosing device from a reservoir to a delivery site, said method comprising the steps of:

moving a piston in a cylinder housing in a piston pump through a stroke between a quiescent position and a position in contact with a detent in said cylinder housing by electromagnetic actuation caused by excitation of an electromagnetic element starting with a turn-on signal and ending with a turn-off signal;
generating a signal by a detector means upon impact of said piston with said detent;
setting the length of an on-time duration following a turn-on signal to a length shorter than a time required for said piston to move from said quiescent position to said detent given fault-free operation and generating said turn-off signal upon the expiration of said on-time duration;
and
lengthening said on-time duration in the absence of a signal from said detector means for a first predetermined number of strokes within a second predetermined number of strokes.

2 more elements

Dependencies are inferred from the claim text.