Freeze-Proof Pressure Sensor With Compressible Elastomer

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Solution Overview

Problem

Pressure sensors are vulnerable to damage from freezing fluids, which can cause significant pressure overload due to volumetric expansion of ice, leading to potential destruction of sensitive components in applications like urea injection systems.

Innovation Solution

A pressure sensor assembly with a compressible element made of elastomeric material, such as silicone or polyurethane foam, is integrated within a housing to absorb volume changes caused by freezing fluids, and a soft adhesive is used to isolate the diaphragm and other fragile surfaces from the fluid, preventing damage and ensuring accurate pressure measurements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If pressure sensors are used in freezing environments, then pressure measurement function is maintained, but the sensor is vulnerable to mechanical damage from ice formation and volumetric expansion

Engineering Contradiction:
Improvesensor durabilityVSAvoidfreezing damage
Core Design Contradiction:
ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A compressible element is installed in advance within the sensor housing to cushion and absorb the volumetric expansion forces generated when fluid freezes. This pre-positioned cushioning mechanism prevents the harmful expansion forces from damaging the sensor components, directly resolving the contradiction between maintaining pressure measurement reliability and protecting against freezing damage.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The compressible element changes its physical state from a compressed state during normal operation to an expanded state when freezing occurs, absorbing the volume change. This parameter change allows the sensor to maintain structural integrity across temperature variations, protecting the sensor while maintaining measurement functionality.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a compressible element is added to protect against freezing, then sensor protection is improved, but device complexity increases

Engineering Contradiction:
Improvefreeze protectionVSAvoidsensor structure
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The compressible element is implemented as a flexible component that can be integrated into the existing sensor housing structure. This flexible element provides freeze protection while maintaining a relatively simple overall device structure, avoiding excessive complexity addition.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The compressible element serves multiple functions: it protects against freezing damage, maintains pressure transmission during normal operation, and accommodates temperature-induced volume changes. This multi-functionality reduces the need for additional separate protection mechanisms, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 effectively protects pressure sensors from mechanical damage due to freezing conditions by absorbing pressure-induced volume changes, maintaining sensor integrity and accuracy across multiple freeze cycles without requiring extensive system modifications.

Implementation Method 1

A compressible element made of elastomeric material, such as silicone or polyurethane foam, is integrated within a housing to absorb volume changes caused by freezing fluids

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a soft adhesive is used to isolate the diaphragm and other fragile surfaces from the fluid, preventing damage

Methodology Applied
Scientific EffectAdhesion: Adhesive

Data Source

PatentEP3186593B1Freeze proof protection of pressure sensors
Publication Date: 2020.06.24 MEASUREMENT SPECIALTIES INC
  • EP3186593B1 patent drawingFigure 1
  • EP3186593B1 patent drawingFigure 2
  • EP3186593B1 patent drawingFigure 3

AI summary

A pressure sensor assembly for measuring the pressure of a first fluid. The assembly having a first housing including a pressure sensing device arranged therein. A diaphragm is arranged on a surface of the first housing and is configured to transmit a force exerted on a first side thereof to the pressure sensing device. A second housing is provided and attached to the first housing. The second housing may be arranged generally circumferentially around the diaphragm. A compressible element is provided and arranged within a compressible element space defined within the second housing. The compressible element is configured to transmit a force exerted thereon by the fluid to the first side of the diaphragm.