Portable Infusion Pump with Electroactive Polymer Diaphragm

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Solution Overview

Problem

Existing insulin pumps are large, heavy, and lack precision in infusion, with limited communication capabilities, making them unsuitable for insulin infusion and posing risks due to potential leaks and unpredictable dosing, especially in cases of hypoglycemia or hyperglycemia.

Innovation Solution

A disposable insulin pump with a diaphragm-type mechanism using electroactive polymer (EAP) or shape memory alloy actuators, featuring valves that prevent communication between intake and discharge, ensuring safety and precision through predictable and repeatable movement, and integrated communication systems for enhanced patient monitoring.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If syringe-type pumps are used, then infusion precision is improved, but device size and weight increase

Engineering Contradiction:
Improveinfusion precisionVSAvoidpump weight
Core Design Contradiction:
Measurement precisionVSWeight of moving object

Solution Approach 1:

The patent replaces the mechanical syringe-piston system with an electroactive polymer diaphragm actuation system. The EAP material responds directly to electrical signals to deform the diaphragm, eliminating the need for mechanical syringes and pistons while maintaining precise infusion control through electrical parameter regulation.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent controls infusion precision by changing electrical parameters (voltage, frequency, amplitude) applied to the electroactive polymer diaphragm. By modulating these electrical parameters, the pump achieves precise control over diaphragm deformation and subsequent fluid delivery, replacing mechanical measurement with electrical parameter control.

Inventive Principle:
Principle #35Parameter changes

2Volume of moving object

If peristaltic pumps with medicament bag are used, then device size is reduced, but infusion precision deteriorates

Engineering Contradiction:
Improvepump sizeVSAvoidinfusion precision
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

The patent replaces the mechanical peristaltic pumping mechanism with an electroactive polymer diaphragm system. This substitution maintains a compact form factor while achieving superior infusion precision through direct electrical actuation of the diaphragm, eliminating the need for complex mechanical peristaltic rollers or pistons.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Device complexity

If passive downflow valves of the same direction are used, then device complexity is reduced, but safety deteriorates due to simultaneous opening under overpressure

Engineering Contradiction:
Improvevalve system complexityVSAvoidinfusion safety
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent employs asymmetric valve configuration where the first and second valves are oriented in opposite directions rather than the same direction. This asymmetric arrangement ensures that under overpressure conditions, only one valve can open at a time, preventing simultaneous opening and the associated safety hazards while maintaining relatively simple valve structures.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent incorporates a check valve mechanism that preemptively prevents backflow and simultaneous valve opening by designing the valve architecture to inherently resist reverse flow. The check valve's one-way flow characteristic is built into the system to counteract potential overpressure conditions before they can cause safety issues.

Inventive Principle:
Principle #9Preliminary anti-action

4Measurement precision

If electroactive polymer diaphragm is used, then infusion precision is improved through predictable movement, but manufacturing complexity increases

Engineering Contradiction:
Improveinfusion precisionVSAvoidmanufacturing complexity
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The patent implements a disposable pump system where the entire pump unit, including the electroactive polymer diaphragm, is discarded after single use. This approach simplifies manufacturing by eliminating the need for complex sterilization processes and quality control procedures for reusable components, while the EAP diaphragm's predictable response ensures consistent infusion precision across all units.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

5Loss of information

If communication systems are integrated, then patient monitoring capability is improved, but device complexity and power consumption increase

Engineering Contradiction:
Improvecommunication capabilityVSAvoidsystem complexity
Core Design Contradiction:
Loss of informationVSDevice complexity

Solution Approach 1:

The patent replaces complex wired communication infrastructure with wireless communication technology. This substitution enables patient monitoring and data transmission without physical connections, reducing the complexity of wiring and connection interfaces while maintaining robust communication capabilities for transmitting infusion data and receiving monitoring information.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The pump achieves high infusion precision, safety, and effective communication, preventing accidental drug transfer and enabling reliable insulin delivery, thus protecting patients from severe hypoglycemia and hyperglycemia, while being lightweight and suitable for portable use.

Implementation Method 1

the actuator used to move the diaphragm both in the pressure cavity and in the intake valve or, alternatively, in the discharge valve is preferably of electroactive polymer (EAP)

Methodology Applied
Scientific EffectElectroactive polymer: Electroactive Polymer

Implementation Method 2

Alternatively, the actuator of the diaphragm may be a shape memory alloy wire or plate

Methodology Applied
Scientific EffectShape memory alloy: Shape Memory Alloy

Data Source

PatentEP2289579B1Portable infusion pump
Publication Date: 2013.11.20 MICREL MEDICAL DEVICES SA
  • EP2289579B1 patent drawingFigure 1~3c
  • EP2289579B1 patent drawingFigure 4a~5b
  • EP2289579B1 patent drawingFigure 6~7b

AI summary

Described is an infusion pump comprising electronic infusion regulating means with wired or wireless communication means and a power source, a medicament bag (7) and an infusion device, said infusion device being in fluid communication with said medicament bag (7) and comprising two valves (1, 2), a pressure cavity (4) provided between said two valves (1, 2) and a membrane (3) covering said cavity (4), wherein said infusion device comprises at least two active actuators, preferably either made of electroactive polymer so as to form a self actuating membrane (3) or made of shape memory alloy wire, one of said actuators being adapted to apply pressure to said membrane (3) for fluid displacement in said cavity (4), and the other of said actuators being adapted to operate one of said valves which is adapted to passively close in the flow direction of a fluid from said medicament bag (7) through the cavity (4), wherein the other of said valves is adapted to, in particular passively, close in a direction opposite to said flow direction.