Temperature-Controlled Pressure Switch Testing

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Solution Overview

Problem

Existing methods for testing temperature-compensated pressure switches in pressure vessels, such as those in aircraft fire extinguishers, are laborious, costly, and environmentally harmful, as they require emptying and refilling the primary pressure vessel, and do not effectively assess the mechanical and electronic functionality.

Innovation Solution

A method and device that generate a temperature gradient between the primary and secondary pressure chambers to simulate the triggering pressure gradient, allowing for selective heating or cooling of the chambers to test the pressure switch without emptying the vessel, using temperature control devices and sensors to ensure efficient and environmentally friendly testing.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the primary pressure vessel is emptied and refilled to test the pressure switch, then the pressure switch functionality can be tested, but the process becomes labor-intensive, costly, and environmentally harmful

Engineering Contradiction:
Improvepressure switch functionalityVSAvoidtesting process
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention extracts the essential testing function from the complex process of emptying and refilling the entire pressure vessel. By applying temperature control directly to the secondary pressure chamber, the method isolates and activates only the pressure switch mechanism for testing, leaving the primary pressure vessel intact and filled with its operating contents.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention changes the physical parameter of temperature in the secondary pressure chamber to generate the required pressure differential for testing. By heating or cooling the secondary chamber, a pressure gradient is created that simulates the conditions needed to activate the pressure switch, enabling functional testing without mechanical intervention on the primary vessel.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a strong external magnetic field is used to trigger the reed switch, then the electronic circuit can be tested, but mechanical functionality and trigger pressure cannot be assessed

Engineering Contradiction:
Improveelectronic circuitVSAvoidmechanical switching capability
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention uses temperature as an intermediary parameter to indirectly generate the mechanical pressure differential needed for testing. By controlling the temperature of the secondary pressure chamber, the system creates a pressure gradient that mechanically actuates the pressure switch, thereby enabling assessment of both mechanical functionality and trigger pressure thresholds.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Reliability

If the pressure ratio between operating pressure and trigger pressure is kept large (2-4), then unintentional triggering is prevented, but the pressure switch becomes less sensitive to actual pressure drops

Engineering Contradiction:
Improveprevention of unintentional triggeringVSAvoidsensitivity to pressure drops
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The invention temporarily changes the pressure parameter in the secondary chamber by applying temperature control, creating a simulated pressure differential that is sufficient to trigger the pressure switch. This allows the system to test sensitivity and trigger thresholds without requiring actual large pressure drops in the primary operating system.

Inventive Principle:
Principle #35Parameter changes

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

Enables reliable mechanical and electronic testing of the pressure switch within a short time, avoiding unnecessary intervention and environmental impact, while providing precise control to prevent thermal stress and ensure accurate assessment of the switching mechanism.

Implementation Method 1

a temperature gradient is set between the primary pressure chamber and the secondary pressure chamber by using at least one temperature control device

Methodology Applied
Scientific EffectTemperature gradient: Temperature Gradient

Implementation Method 2

generate a pressure gradient between the primary pressure chamber and the secondary pressure chamber which corresponds at least to the trigger pressure gradient of the pressure switch

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Data Source

PatentEP3365908B1Method and device for testing a temperature-compensated, pressure-gradient-controlled pressure switch
Publication Date: 2021.08.11 LUFTHANSA TECHNIK AG
  • EP3365908B1 patent drawingFigure 1~2

AI summary

The invention relates to a method for testing a temperature-compensated, pressure-gradient-controlled pressure switch (1), which is pneumatically associated with a primary pressure chamber (2) and has a secondary pressure chamber (3) for temperature compensation, wherein a temperature gradient is set between the primary pressure chamber (2) and the secondary pressure chamber (3) by using at least one temperature control device (4, 5), which temperature gradient is sufficiently large to produce a pressure gradient, which corresponds at least to the triggering pressure gradient of the pressure switch (1), between the primary pressure chamber (2) and the secondary pressure chamber (3).