Flex-stroke Infusion Pump Plunger Dynamics

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Solution Overview

Problem

Infusion pumps face challenges in maintaining accurate and prolonged fluid delivery due to the degradation of infusion tubes, which are prone to deform or rupture under continuous compression, leading to precision issues and the need for complex flow rate compensation algorithms.

Innovation Solution

An infusion pump with a controller that maintains the infusion tube in partially squeezed positions, switching between intermediate squeezing states to prevent tube degradation and ensure constant flow, eliminating the need for compensation algorithms by maintaining tube springiness and full engagement with the plunger.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the plunger continuously compresses the infusion tube to maximum extent, then the delivery precision is improved, but the tube degrades and ruptures over time

Engineering Contradiction:

Improvedelivery precisionVSAvoidtube durability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The plunger dynamically adjusts its position between upper and lower limits, maintaining continuous contact with the tube while varying the compression level. This dynamic positioning prevents the tube from experiencing static maximum compression that would cause degradation, while still ensuring adequate squeezing for precise delivery control throughout the infusion period.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system employs periodic oscillation of the plunger between upper and lower positions during operation. This periodic movement creates a rhythm of compression and slight relaxation that prevents continuous stress accumulation in the tube material, thereby extending tube life while maintaining delivery precision through controlled periodic squeezing.

Inventive Principle:

Principle #19Periodic action

2Stability of the object's composition

If the plunger elevates to uppermost position without touching the tube, then the tube springiness is restored, but the delivery accuracy deteriorates due to loss of engagement

Engineering Contradiction:

Improvetube springinessVSAvoiddelivery accuracy

Core Design Contradiction:

Stability of the object's compositionVSManufacturing precision

Solution Approach 1:

Instead of completely releasing the tube at the upper position, the plunger maintains partial contact and applies minimal continuous compression. This partial action ensures the tube remains engaged with the plunger for accurate positioning while allowing sufficient relaxation to maintain springiness, avoiding the extremes of full release or maximum compression.

Inventive Principle:

Principle #16Partial or excessive action

Solution Approach 2:

The system proactively maintains continuous mild compression as a cushioning measure to prevent complete loss of tube-plunger engagement. This beforehand cushioning ensures that the tube remains sufficiently engaged for accurate delivery control while avoiding the harsh effects of abrupt engagement/disengagement cycles.

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Manufacturing precision

If complex flow rate compensation algorithms are implemented, then the precision is maintained, but the device complexity increases

Engineering Contradiction:

Improveflow rate precisionVSAvoidcontrol algorithm complexity

Core Design Contradiction:

Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent replaces complex software compensation algorithms with a simplified mechanical solution: continuous physical contact between the plunger and tube through controlled oscillation. This mechanical approach inherently maintains delivery precision through consistent mechanical engagement, eliminating the need for complex computational compensation of tube degradation effects.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The system uses the natural springiness of the tube combined with continuous plunger contact to self-regulate flow delivery. The tube's elastic properties work in conjunction with the plunger's continuous engagement to maintain consistent flow rates without requiring external compensation algorithms, allowing the system to self-correct for tube degradation over time.

Inventive Principle:

Principle #25Self-service

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 solution achieves stable and accurate infusion fluid delivery over extended periods, reducing tube stress and preventing continuous ascending, thus maintaining a consistent flow rate and enhancing operational reliability.

Implementation Method 1

the plunger is configured to squeeze a section of an infusion tube... maintaining tube springiness... preventing continuous ascending

Methodology Applied

Scientific EffectElasticity: Elasticity

Data Source

PatentUS12011567B2Flex-stroke infusion pump

Publication Date: 2024.06.18 EITAN MEDICAL LTD

AI summary

An infusion pump including a plunger, a proximal valve located proximally to the plunger, a distal valve located distally to the plunger, and a controller configured to trigger the position of the plunger, such that both in its upper position and its lower position, the plunger squeezes a section of an infusion tube, such that opposite sides of an inner surface of the section do not contact one another.