Patch Infusion Pump With Sequential Shape-Memory Valve Actuation
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Solution Overview
Problem
Existing patch pumps face challenges in reducing volume and weight while maintaining reliability and accuracy in insulin infusion, as current infusion mechanisms, such as those using miniature reduction motors or shape-memory alloys, are insufficient.
Innovation Solution
A patch infusion pump with an infusion assembly featuring multiple valve mechanisms, including abutting plungers, memory metal members, and reset elastic members, which are energized and de-energized in a preset sequence to create negative and positive pressures, allowing for efficient medication delivery through an infusion tube.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Weight of moving object
If a miniature reduction motor or shape-memory alloy is used to drive the reduction gear, then the patch pump can be made smaller and lighter, but the volume and weight reduction is limited and cannot meet user requirements
Solution Approach 1:
The patent replaces the traditional miniature reduction motor with a shape-memory alloy-based actuation system. The shape-memory alloy wire, when heated by a heating element, transforms from a martensitic to an austenitic structure, automatically pushing the plunger to deliver medication. This eliminates the need for complex reduction gears and motors, significantly reducing weight and volume while maintaining reliable infusion through the inherent memory effect of the shape-memory material
Solution Approach 2:
The patent utilizes the phase transition of shape-memory alloy between martensitic and austenitic states driven by temperature changes. The heating element raises the local temperature, triggering the phase transition that causes the alloy to contract and push the plunger. This phase transition mechanism provides reliable actuation without requiring complex mechanical drive systems, achieving both weight reduction and operational reliability
2Duration of action of moving object
If the patch pump is worn for a long time, then continuous infusion can be maintained, but the volume and weight requirements become more stringent
Solution Approach 1:
By replacing the heavy reduction motor with a lightweight shape-memory alloy actuator, the patent enables long-duration wear without excessive weight. The SMA-based system provides sufficient force for continuous infusion over extended periods while keeping the overall pump weight low enough for comfortable patient wear during daily activities
3Measurement precision
If multiple valve mechanisms are used to control medication flow, then infusion accuracy is improved, but device complexity increases
Solution Approach 1:
The patent divides the infusion control into multiple independent valve mechanisms, each controlled by separate shape-memory alloy actuators. These valves are arranged along the infusion pathway to control different stages of medication delivery. Each valve operates independently through its own SMA actuator, enabling precise control of infusion timing and volume while maintaining a relatively simple overall structure based on repeated modular units
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 patch infusion pump achieves a smaller size and lighter weight, improving user experience and infusion accuracy, while ensuring reliable medication delivery and safety by isolating the liquid medication from the body when not in use.
Implementation Method 1
the memory metal member contracts when being energized and drives the abutting plunger to move away from the infusion tube
Implementation Method 2
the reset elastic member is configured to reset the abutting plunger to a position for abutting against the infusion tube after the memory metal member is de-energized
Implementation Method 3
the infusion tube is configured to suck the liquid medication from a liquid reservoir under the negative pressure in the infusion tube
Implementation Method 4
pump the liquid medication to a medication output mechanism under the positive pressure in the infusion tube
Data Source
AI summary
Provided are a patch infusion pump and an infusion method. The patch infusion pump includes an infusion tube and an infusion assembly with multiple valve mechanisms. Each valve mechanism includes an abutting plunger, a memory metal member, and a reset elastic member, the abutting plunger is configured to abut against the infusion tube, the memory metal member contracts when being energized and drives the abutting plunger to move away from the infusion tube, and the reset elastic member is configured to reset the abutting plunger after the memory metal member is de-energized. Memory metal members are energized and de-energized according to a preset sequence for operation to enable deformation of the infusion tube, the infusion tube is configured to suck the liquid medication from a liquid reservoir under the negative pressure and pump the liquid medication to a medication output mechanism under the positive pressure.