Pressure Measuring Cell Thermal Shock Compensation

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Solution Overview

Problem

Existing pressure measurement methods, particularly in ceramic and metallic pressure measuring cells with thin membranes, face significant measurement errors due to rapid temperature changes, which cannot be adequately compensated for using conventional temperature compensation techniques.

Innovation Solution

A method and measuring arrangement that utilize two temperature sensors to detect temperature differences between the membrane and the base body, distinguishing between dynamic, quasi-static, and static phases of temperature changes to adaptively correct pressure measurements, allowing for finer resolution and effective compensation of thermal shocks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If conventional temperature compensation techniques are used in pressure measuring cells, then temperature dependence of pressure measurement can be compensated under thermal equilibrium conditions, but rapid temperature changes cause significant measurement errors that cannot be meaningfully compensated

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidmeasurement errors due to rapid temperature changes
Core Design Contradiction:
Measurement precisionVSObject-affected harmful factors

Solution Approach 1:

The temperature compensation process is segmented into three distinct phases: dynamic phase (rapid temperature changes where compensation is not applied), quasi-static phase (intermediate state where partial compensation is applied), and static phase (steady state where full compensation is applied). This segmentation allows the system to adapt its compensation strategy based on the current thermal conditions, resolving the contradiction between maintaining compensation accuracy and responding to rapid temperature changes.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The temperature compensation method transitions from a static compensation approach to a dynamic one by continuously monitoring the rate of temperature change. The system adjusts its compensation behavior in real-time based on whether the temperature is changing rapidly, slowly, or is stable, enabling meaningful compensation only when thermally appropriate conditions exist while avoiding erroneous corrections during rapid transitions.

Inventive Principle:
Principle #15Dynamics

2Device complexity

If a single temperature sensor is used to detect temperature for compensation, then the device complexity is reduced, but the ability to detect temperature gradients and differentiate phases of temperature change is insufficient

Engineering Contradiction:
Improvenumber of temperature sensorsVSAvoidtemperature detection accuracy for phase differentiation
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The temperature detection function is segmented into multiple sensing points: a first temperature sensor detects the temperature of the membrane (front side), and a second temperature sensor detects the temperature of the base body (back side). This spatial segmentation enables the system to detect temperature gradients across the pressure measuring cell, which is critical for identifying whether the system is in a dynamic, quasi-static, or static phase, thereby justifying the additional sensor complexity through improved measurement capability.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system adds a temporal dimension to temperature measurement by continuously monitoring temperature at multiple spatial points and analyzing the rate of change over time. This dimensional expansion from single-point static temperature measurement to multi-point dynamic temperature field monitoring enables phase differentiation and adaptive compensation strategy selection.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 approach enables precise compensation of temperature-induced measurement errors, reducing the influence of rapid temperature changes and maintaining accurate pressure measurements by differentiating and correcting for individual phases of temperature fluctuations.

Implementation Method 1

a first temperature sensor which is suitably designed and arranged to detect a first temperature of the membrane

Methodology Applied
Scientific EffectTemperature detection:

Implementation Method 2

a second temperature sensor which is suitably designed and arranged to detect a second temperature of the base body

Methodology Applied
Scientific EffectTemperature detection:

Implementation Method 3

a membrane arranged on the front of the base body and deformable by the pressure of the fluid

Methodology Applied
Scientific EffectPressure-induced deformation:

Implementation Method 4

a distance between the membrane electrode and the measuring electrode changes, so that a change in capacity can be detected

Methodology Applied
Scientific EffectCapacitance change: Capacitance

Data Source

PatentEP3124937B1Method for determining a pressure and measuring assembly for same
Publication Date: 2018.05.02 VEGA GRIESHABER GMBH & CO
  • EP3124937B1 patent drawingFigure 1~2
  • EP3124937B1 patent drawingFigure 3a
  • EP3124937B1 patent drawingFigure 3b

AI summary

A method for determining the pressure of a fluid using a pressure measuring cell (1, 21) comprising a base body (3, 23), a membrane (2, 22) arranged on the front of the base body and deformable by the pressure of the fluid, a first temperature sensor (5, 25) suitable for detecting a first temperature (T1) of the membrane (2, 22) and/or of the fluid adjacent to the membrane (2, 22), and a second temperature sensor (6, 26) suitable for detecting a second temperature (T2) of the base body (3, 23) and/or an average temperature of the pressure measuring cell (1, 21), wherein a temperature difference (DT) between the first temperature (T1) and the second temperature (T2) is determined, characterized in that a measurement signal from the pressure measuring cell (1, 21) is generated depending on a change in the temperature difference (DT) over time.21) The temperature difference (DT) is corrected and/or smoothed as an output value (AW), either directly or depending on a quantity.