Ambulatory infusion membrane pump

Abstract

Ambulatory membrane pump intended for medical use e.g. for infusion purposes, consisting of two main parts: 1) the basic device with motor drive and computer, and 2) the administration set, which is disposable. The arrangement with check valves in both ends of the administration system safeguards that no leakage happens when gravitational forces are acting, due to height differences between fluid bag and needle.

Description

TECHNICAL FIELD [0001] The present invention relates to fluid injection pumps with disposable membrane pump and tubing intended for injection of medicines, pain relief and fluids related to nursing. BACKGROUND OF THE INVENTION [0002] Membrane injection pumps are used in many applications, as ultra small plastic pumps intended for medical applications. However, when used for portioning fluids, as medicines, with a high degree of precision, usually other pumping methods dominate the market. Such pumps are syringe or plunger pumps, as well as peristaltic pumps. [0003] Transporting fluids from a container to an injection needle with a high degree of precision is claimed as to the dosage, especially concerning new, potent medicines. Not intended leakage through tubing arrangement must be safely restricted, as when a container filled with medicine is placed above the needle, the static pressure can generate a flow if the system is not restricted against this. [0004] Examples of prior art ...

AI Technical Summary

Benefits of technology

[0012] The present invention is a membrane pump consisting of two main bodies: the computer with its housing and the administration set. The membrane pump works distinctly with equal membrane movements repeated as a decided position of the stroke. A rotational electric motor with a gear is positioned in the housing, and the outgoing shaft moves a screw in connection with a threaded plunger rod and at the other end in connection with the membrane tap. At the end cover on the housing the membrane pump is snapped into an attachment consisting of a guide rail and a shoulder on the pump house, which easily is snapped on when the pump house is in exact position. The electrical motor has a permanent magnet and a sensor which registrates each revolution of the motor and communicates signals to the computer, which registers each signal in forward respectively backward mode of the driving motor, thus counting each revolution and registers the exact position of the screw on the plunger rod.

[0014] In a system with tubes and pump, elastic effects can arise, for instance when the pump suddenly is cut off (which happens when the polarity reversal activates for intended reversal of the plunger rod). When the pressure leaves the system, elastic effects arise; the volume of the system decreases. In order to prevent unintended through flow in the system according to such elastic effects, check valves are positioned in each end of the tubing; the inflow check valve close to the fluid container and the outflow check valve close to the needle arrangement.

Problems solved by technology

Many of these pumps are very sophisticated and sometimes very complicated, as U.S. Pat. No. 5,482,438 and very expensive for the hospitals.

However the cassette is with its arrangements of check valves a little bit complicated, and the amount of material in the cassette is significantly high.

When initially filling up the pump, de-airing obviously will become problematic.

Document U.S. Pat. No. 4,846,636 describes a piston pump with a complicated construction, where it is very difficult to de-air a pumped fluid In a controlled way.

This pump has a large dead space, which means that a substantial amount of fluid is interlocked into the pump when a pumping operation is ended.

A careful control of the pumped amount of fluid by use of different piston stroke lengths are not possible in any of the designs of U.S. Pat. No. 4,846,636 and WO 99 / 21596.

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