Infusion device and driving mechanism for same

Abstract

A drive mechanism for delivery of infusion medium has a coil and an armature moveable toward a forward position, in response to the electromagnetic field produced by activation of the coil. A piston is moveable axially within a piston channel to a forward position, in response to movement of the armature to its forward position. The armature and piston are moved toward a retracted position, when the coil is not energized. In the retracted position of the piston, a piston chamber is formed between the piston and a valve member and is filled with infusion medium. As the piston is moved to its forward position, the piston chamber volume is reduced and pressure within the piston chamber increases to a point where the pressure moves the valve member into an open position through an outlet.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS [0001] Embodiments of the present invention claim priority from a U.S. Provisional Application entitled “Infusion Device and Driving Mechanism For Same,” Ser. No. 60 / 317,886, filed Sep. 7, 2001, the contents of which are incorporated by reference herein.FIELD OF THE INVENTION [0002] The present invention relates generally to infusion devices, systems and processes and, in particular embodiments to implantable infusion devices, systems and processes employing a drive mechanism configuration which allows the device to have a relatively thin form factor and use power efficiently. Further embodiments of the invention relate to drive mechanisms and processes of making and using such drive mechanisms for infusion devices and systems. RELATED ART [0003] Infusion devices are typically used to deliver an infusion media, such as a medication, to a patient. Implantable infusion devices are designed to be implanted in a patient's body, to administer an in...

AI Technical Summary

Benefits of technology

[0007] Preferred embodiments of the invention relate to such devices and drive mechanisms configured for implantation in a patient's body. Configurations described herein allow the drive mechanism and, thus, the infusion device to have a relatively small thickness dimension, for example, to minimize trauma to the implant recipient (referred to herein as the patient).

[0012] The infusion device further includes a drive mechanism having an inlet coupled in fluid flow communication with the reservoir and an outlet coupled in fluid flow communication with the infusion device housing outlet. In one embodiment, a filter may be disposed between the reservoir and the drive mechanism (or as part of the inlet of the drive mechanism). In a further embodiment, expandable and compressable devices, such as one or more volume compensators or accumulators, which may also be, for example, accumulators, also may be disposed in the flow path between the reseervoir and the drive mechanism inlet, to dampen surges and ebbs in the flow.

[0015] Embodiments of the invention employ a coaxial arrangement of the piston, the piston channel and the coil, to provide significant advantages with respect to providing a relatively thin form factor and efficient power usage. A number of features can each provide or be combined to contribute to a reduction in the thickness form factor of the drive mechanism. For example, a coaxial arrangement of components can be implemented with a smaller thickness form factor than alternative arrangements in which components are arranged in series with each other in the thickness dimension. Embodiments may include an inlet volume on one side of the coil and an outlet chamber on the opposite side of the coil, with a flow passage through the piston channel, such that the coil and flow channel share a common portion of the thickness dimension. The armature may be located within the inlet volume and, thus, share a common portion of the thickness dimension with the inlet volume. The outlet chamber may be centrally located within the same housing that has the coil cup and formed in relatively close proximity to the coil cup in the thickness dimension of the housing.

[0017] In addition, a number of features described herein can provide, or be combined to contribute to, the efficient use of power to, prolong the operational life of the drive mechanism. One manner of improving the operational life of an infusion device according to embodiments of the present invention, is to lower the power consumption requirements of the drive mechanism by employing a coaxial coil and piston configuration and one or more features for making highly efficient use of electromagnetic energy. Another manner of improving the operational life of a device according to embodiments of the invention is to reduce the number of operations of the drive mechanism required over a given period of time, by pumping reduced volumes of a higher concentration infusion medium (an infusion medium with a higher concentration of active ingredients) or pumping higher concentration volumes at reduced intervals.

Problems solved by technology

In some devices, when the batteries die, the devices are simply thrown away.

Also, as the battery power supplies for such devices have limited capacities, some devices typically require multiple replacements of batteries over their operational life.

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