Capacitive Pressure Cell Infrared Temperature Correction

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Solution Overview

Problem

Capacitive pressure measuring cells face measurement errors due to temperature fluctuations when measuring rapidly changing mediums, as existing correction methods are inadequate for large temperature differences between the measuring membrane and the base, leading to erroneous pressure readings.

Innovation Solution

Incorporating an infrared sensor on the base body to measure the temperature of the measuring membrane by detecting infrared radiation, eliminating the need for additional layers or complex resistance tracks, and using commercially available components to maintain pressure tightness and reduce production costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If temperature correction is performed using base body temperature only, then the pressure measurement can be corrected for slow temperature changes, but measurement errors occur when there is a large temperature difference between the measuring membrane and base body

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidmeasurement reliability under rapid temperature changes
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

An infrared-transparent window is introduced as an intermediary component between the measuring membrane and the infrared sensor. This window allows infrared radiation to pass through while maintaining the structural integrity and pressure tightness of the measuring cell, enabling non-contact temperature measurement of the measuring membrane without direct thermal coupling

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The patent replaces contact-based temperature measurement methods with non-contact infrared thermography. Instead of using thermal conduction through physical contact (which causes thermal lag), the system uses infrared radiation detection to measure the temperature of the measuring membrane remotely, eliminating the thermal coupling problem

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Measurement precision

If resistance tracks are added to the measuring membrane for temperature measurement, then temperature compensation can be achieved, but production complexity and costs increase

Engineering Contradiction:
Improvetemperature measurement capabilityVSAvoidproduction complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The temperature measurement function is extracted from the measuring membrane structure itself and performed by a separate infrared sensor system. This eliminates the need to modify the measuring membrane with additional layers or resistance tracks, keeping the membrane design simple and production straightforward

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The base body is designed to serve multiple functions: it provides structural support, maintains pressure tightness, and houses the infrared sensor system for temperature measurement. This multi-functionality reduces the need for additional separate components and simplifies the overall device structure

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

3Measurement precision

If the infrared sensor is integrated into the base body, then temperature measurement of the measuring membrane is enabled, but pressure tightness must be maintained

Engineering Contradiction:
Improvemembrane temperature measurementVSAvoidpressure tightness
Core Design Contradiction:
Measurement precisionVSReliability

Solution Approach 1:

The base body is segmented into functional zones: a pressure-tight measuring chamber for pressure measurement and an infrared sensor housing for temperature measurement. The infrared sensor is positioned in a dedicated housing that allows optical access to the measuring membrane while maintaining the pressure boundary of the measuring chamber

Inventive Principle:
Principle #1Segmentation

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 precise and rapid temperature measurement of the measuring membrane, correcting pressure measurement errors caused by temperature changes while simplifying production and reducing costs, allowing for accurate pressure detection in capacitive pressure measuring cells.

Implementation Method 1

the base body is designed with an infrared sensor for measuring the temperature of the measuring membrane by detecting the infrared radiation emitted from its second side

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Data Source

PatentEP2784461B1Pressure measurement cell for detecting the pressure of a medium adjoining the measurement cell
Publication Date: 2018.05.02 VEGA GRIESHABER GMBH & CO
  • EP2784461B1 patent drawingFigure 1~2

AI summary

The pressure-measuring cell (1) has a resilient measuring membrane (2) with a side (2a) that is provided partially in contact with the medium and with another side (2b) that is remote from the medium. The measuring cell further has a base body (3) that is disposed opposite to the latter side of the measuring membrane. The base body is formed with an infra-red sensor (4) for measuring the temperature of the measuring membrane by measuring the infra-red radiation radiated from the latter side of the measuring membrane.