Pressure Sensor Inclination Correction via Hydrostatic Compensation

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Solution Overview

Problem

Pressure sensors with hydraulic paths face significant relative measurement errors due to differences in hydrostatic pressure between the pressure inlet opening and the deformation body, especially in sensors with small measurement ranges, which existing technologies fail to correct accurately.

Innovation Solution

Incorporating a pressure sensor with a hydraulic path, a temperature sensor, an inclination sensor, and a processing circuit that determines the density of the transmission fluid based on temperature measurements and inclination values to correct the measured pressure values for hydrostatic pressure differences and other dependencies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the pressure inlet opening is spaced apart from the deformation body by a distance value in the hydraulic path, then the pressure sensor can be structurally designed with separate pressure inlet and measurement points, but the pressure present at the deformation body deviates from the pressure at the pressure inlet opening by the difference in hydrostatic pressure, leading to significant relative measurement errors

Engineering Contradiction:
Improvestructural design flexibilityVSAvoidpressure measurement accuracy
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent applies parameter changes by measuring temperature to determine the density of the transmission fluid, then using this density parameter along with the inclination angle and distance value to calculate and correct the hydrostatic pressure difference. This transforms the physical state parameters (temperature, density) into correction factors that compensate for the measurement error caused by the spatial separation between pressure inlet and deformation body.

Inventive Principle:
Principle #35Parameter changes

2Measurement precision

If inclination correction is implemented by taking into account the inclination-dependent height of the liquid column, then the measurement accuracy can be improved, but the device complexity increases due to additional sensors and processing requirements

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidsensor and circuit complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent implements multi-functionality by using a single processing circuit that performs multiple correction functions: it processes inclination sensor data to determine the angle of the hydraulic path, processes temperature sensor data to determine fluid density, and combines these parameters with the distance value to calculate hydrostatic pressure correction. This integrated approach achieves comprehensive correction without requiring separate dedicated circuits for each function.

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

Solution Approach 2:

The patent replaces complex mechanical correction mechanisms with electronic sensing and computational correction. Instead of using mechanical devices to physically adjust or compensate for inclination and temperature effects, the invention uses electronic sensors (inclination sensor, temperature sensor) and a processing circuit to calculate and apply correction factors, thereby reducing mechanical complexity while achieving high measurement precision.

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

3Adaptability or versatility

If the transmission liquid density varies with temperature, then the hydrostatic pressure difference changes, but existing technologies fail to correct for temperature-dependent density variations, leading to persistent measurement errors

Engineering Contradiction:
Improvetemperature compensation capabilityVSAvoidpressure measurement accuracy
Core Design Contradiction:
Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent implements feedback by continuously measuring the temperature in the hydraulic path, using this temperature measurement to determine the current density of the transmission fluid, and then applying this density information to correct the pressure measurement in real-time. This closed-loop approach ensures that temperature-dependent density variations are continuously compensated, maintaining measurement accuracy across varying temperature conditions.

Inventive Principle:
Principle #23Feedback

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 enables precise correction of pressure measurements by accounting for hydrostatic pressure differences and temperature-dependent errors, improving the accuracy of pressure sensors and differential pressure sensors across various inclinations and temperatures.

Implementation Method 1

determine a current value for the density of the transmission fluid based on a measured temperature value

Methodology Applied
Scientific EffectTemperature-dependent density: Thermal Expansion

Implementation Method 2

an inclination sensor for determining at least one inclination value dependent on the inclination of the hydraulic path

Methodology Applied
Scientific EffectInclination detection: Accelerometer

Implementation Method 3

the pressure present at the surface of the deformation body deviating from the pressure present at the pressure inlet opening by the difference in the hydrostatic pressure of the transmission liquid

Methodology Applied
Scientific EffectHydrostatic pressure: Pressure Gradient

Data Source

PatentEP2362204B1Pressure sensor device and differential pressure sensor with inclination angle correction
Publication Date: 2012.11.21 ENDRESS & HAUSER GMBH & CO KG
  • EP2362204B1 patent drawingFigure 1
  • EP2362204B1 patent drawingFigure 2~3
  • EP2362204B1 patent drawingFigure 4

AI summary

The transducer (1) has a hydraulic path (3) comprising a channel that is filled with transmission liquid by a solid body or solid body composite e.g. process terminal body (10), capillary spacer (11) and pressure transducer cabinet (14), of a pressure input port (8). A slant sensor (18) determines a slant of the path. A processing circuit (16) is designed based on function of the slant of the path and a value of density of the liquid. Difference of hydrostatic pressure of the liquid between the port and a deformation body (6) is determined through the value representing a distance value.