Flexible Diaphragm Pressure Sensor with Hall Effect Detection

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Solution Overview

Problem

Existing pressure sensors for disposable fluid handling systems, such as those used in blood centrifuges, face challenges in being cost-effective, biologically compatible, and capable of withstanding sterilization while providing noninvasive, accurate pressure measurements without being physically invasive.

Innovation Solution

A sensor apparatus utilizing a flexible diaphragm coupled with a spring and a non-contact Hall Effect sensor to measure pressure changes, allowing for linear displacement conversion and magnetic field detection without direct contact, enabling both positive and negative pressure measurement with a removable and reusable design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a disposable pressure sensor is used in fluid handling systems, then biologically compatibility and sterilization resistance are improved, but cost-effectiveness deteriorates due to the need for expensive sensors in disposable components

Engineering Contradiction:

Improvebiological compatibilityVSAvoidcost-effectiveness

Core Design Contradiction:

ReliabilityVSEase of manufacture

Solution Approach 1:

The pressure sensing system is divided into two segments: a disposable portion containing only the flexible diaphragm and spring mechanism, and a reusable portion containing the expensive Hall Effect sensor and rigid member. This segmentation allows the disposable portion to be biologically compatible and sterilizable while the expensive sensor remains in the reusable portion, resolving the contradiction between biological compatibility and cost-effectiveness.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A flexible diaphragm acts as an intermediary between the fluid pressure and the spring-rigid member assembly. The diaphragm transmits pressure mechanically without requiring direct contact between the fluid and the sensor, enabling the use of a reusable Hall Effect sensor while maintaining biological compatibility in the disposable portion.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Measurement precision

If a non-contact Hall Effect sensor is used, then measurement accuracy and noninvasive detection are improved, but device complexity increases due to the need for magnetic field detection mechanisms

Engineering Contradiction:

Improvepressure measurement accuracyVSAvoidsensor mechanism complexity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The mechanical contact-based pressure measurement system is replaced with a magnetic field-based Hall Effect sensor system. The spring's mechanical displacement is converted into magnetic field variations that can be detected non-contactly, improving measurement precision while the modular design keeps the complexity contained in the reusable portion.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of operation

If a flexible diaphragm is used for pressure sensing, then noninvasive measurement capability is improved, but structural stability deteriorates due to the flexibility required for pressure response

Engineering Contradiction:

Improvenoninvasive measurement capabilityVSAvoidstructural stability

Core Design Contradiction:

Ease of operationVSStability of the object's composition

Solution Approach 1:

The flexible diaphragm is merged with a spring mechanism and rigid member assembly. The diaphragm provides the necessary flexibility for noninvasive pressure response, while the spring and rigid member provide structural stability and mechanical advantage, combining the benefits of both flexible and rigid components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

A flexible diaphragm (thin film) is used as the pressure-sensitive element that can deform in response to pressure changes without requiring direct fluid contact. This flexible shell approach enables noninvasive measurement while the associated spring mechanism compensates for any structural stability concerns.

Inventive Principle:

Principle #30Flexible shells and thin films

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

This solution provides a cost-effective, biologically compatible, and noninvasive pressure measurement system that can withstand sterilization, ensuring accurate pressure detection and easy disposable component replacement, enhancing the reliability and efficiency of fluid processing systems.

Implementation Method 1

a non-contact Hall Effect sensor to measure pressure changes

Methodology Applied

Scientific EffectHall Effect: Hall Effect

Implementation Method 2

a flexible diaphragm coupled with a spring

Methodology Applied

Scientific EffectSpring: Spring

Data Source

PatentUS10188784B2Apparatus with rigid member for sensing fluid pressure

Publication Date: 2019.01.29 FENWAL INC

AI summary

One embodiment relates to a pressure sensor apparatus, including a housing with a flexible member and an aperture configured to receive a fluid. The pressure sensor apparatus further includes a first member disposed on the flexible member, a second member removably coupled to the first member configured to move in response to a pressure of the fluid and a sensor configured to detect the movement of the second member. The pressure sensor apparatus generates a pressure signal for the fluid based on the displacement of the second member.