Medical Injector Pressure Threshold Detection for Leak Prevention

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Solution Overview

Problem

In medical injectors, increased pressure in the fluid line due to resistance from subcutaneous tissue can lead to leaks and failure to deliver the full medicament dose, causing device damage and contamination risks.

Innovation Solution

A pressure threshold detector is integrated into the medical injector, comprising a first and second member with a cantilever arm and protrusion mechanism that moves from a retracted to an extended position when pressure exceeds a predetermined threshold, activating a switch to prevent further pressure increase.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the medical injector delivers fluid at a high flow rate, then the productivity of drug delivery is improved, but the pressure in the fluid line increases causing leaks and device failure

Engineering Contradiction:

Improvedrug delivery rateVSAvoiddevice integrity

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The pressure threshold detector is pre-configured with a predetermined pressure threshold and cam profiles that will automatically activate the switch when pressure reaches the critical level, preventing leaks and device failure before they occur

Inventive Principle:

Principle #10Preliminary action

Solution Approach 2:

The detector provides real-time feedback on fluid line pressure through the cam mechanism and switch activation, allowing the system to monitor and respond to pressure changes that could compromise device integrity

Inventive Principle:

Principle #23Feedback

2Strength

If the tissue resistance is high, then the mechanical properties of subcutaneous tissue are maintained, but the pressure builds up exceeding the threshold and compromising fluid path integrity

Engineering Contradiction:

Improvetissue mechanical propertiesVSAvoidpressure-induced leaks

Core Design Contradiction:

StrengthVSObject-affected harmful factors

Solution Approach 1:

The high tissue resistance that causes pressure buildup is converted into a useful signal by the pressure threshold detector, which uses the pressure itself to activate the switch and alert the system to potential leakage conditions

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The cam mechanism acts as an intermediary between the pressure buildup caused by tissue resistance and the switch activation, translating the mechanical pressure into a discrete on/off signal that can be processed by the control system

Inventive Principle:

Principle #24Intermediary (Mediator)

3Measurement precision

If the pressure threshold detector uses a complex mechanism, then the measurement precision of pressure threshold is improved, but the device complexity increases

Engineering Contradiction:

Improvepressure threshold detection accuracyVSAvoiddetector structure

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The detector uses the pressure itself to drive the cam mechanism and activate the switch, eliminating the need for external power sources or complex electronic sensing circuits while maintaining accurate threshold detection

Inventive Principle:

Principle #25Self-service

Solution Approach 2:

The mechanical cam and switch mechanism provides a simple, reliable, and cost-effective solution for pressure threshold detection that is suitable for single-use medical devices, avoiding the need for expensive electronic components

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

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 pressure threshold detector effectively prevents pressure from exceeding safe limits, thereby preventing leaks and ensuring the full dose of medicament is delivered, while also protecting the device from damage and contamination.

Implementation Method 1

The second member is moveable from the retracted position to the extended position when a pressure within the inlet passageway exceeds a predetermined pressure

Methodology Applied

Scientific EffectPressure: Pressure Increase

Data Source

PatentUS20250041517A1Pressure Threshold Detector for Medical Injector

Publication Date: 2025.02.06 BECTON DICKINSON & CO

AI summary

A pressure threshold detector for a medical injector includes a first member, a second member moveable relative to the first member between a retracted position and an extended position, an inlet passageway configured to be in fluid communication with a fluid line, a cantilever arm having a cam surface, and a protrusion having a first cam profile and a second cam profile. The cam surface of the cantilever arm is engaged with the first cam profile of the protrusion when the second member is in the retracted position, and the cam surface of the cantilever arm is engaged with the second cam profile of the protrusion when the second member is in the extended position. The second member is moveable from the retracted position to the extended position when a pressure within the inlet passageway exceeds a predetermined pressure.