Pressure Sensor Insulator Plate Hydraulic Compression

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Solution Overview

Problem

Existing pressure sensors with semiconductor transducers face challenges in minimizing the volume of the hydraulic path and transmission liquid due to complex assembly processes and limitations in reducing the free volume, leading to temperature-dependent deflections and inaccurate pressure measurements.

Innovation Solution

A pressure sensor design featuring a semiconductor pressure transducer with a hydraulic path, a packing to fill voids between metallic walls, and an insulator plate with complementary fastening means for secure assembly, allowing for automatic assembly and minimizing the volume of the transmission liquid by reducing the annular gap between the filling body and the converter chamber.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a spring is used to prestress the insulator plate against the filling body, then the insulator plate is securely held in position and electrical insulation is provided, but the free volume required for the spring working stroke cannot be easily limited and the assembly requires great manual effort

Engineering Contradiction:
Improvesecure positioning of insulator plateVSAvoidassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The spring component is completely removed from the assembly. The insulator plate is directly pressed against the filling body by the compression force generated by the liquid in the hydraulic path, eliminating the need for mechanical fastening elements and reducing assembly complexity while maintaining secure positioning.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The liquid in the hydraulic path serves a dual function: it provides both the hydraulic transmission function and the compression force to press the insulator plate against the filling body. This self-service mechanism eliminates the need for separate spring components and reduces the number of parts.

Inventive Principle:
Principle #25Self-service

2Measurement precision

If the annular gap between the filling body and converter chamber wall is reduced to minimize transmission liquid volume, then measurement accuracy is improved, but the assembly becomes more difficult and manual effort increases

Engineering Contradiction:
Improvepressure measurement accuracyVSAvoidassembly ease
Core Design Contradiction:
Measurement precisionVSEase of manufacture

Solution Approach 1:

The liquid in the hydraulic path generates compression force that automatically presses the filling body against the converter chamber wall, minimizing the annular gap without requiring complex assembly procedures. The liquid's own pressure serves to seal and position the components.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The compression force parameter is changed from being mechanically provided (springs) to being hydraulically provided (liquid pressure). This parameter change allows the system to automatically adapt the gap size based on operating conditions while maintaining manufacturing simplicity.

Inventive Principle:
Principle #35Parameter changes

3Measurement precision

If filling bodies are introduced to fill production-related cavities and minimize hydraulic path volume, then temperature-dependent deflections are reduced, but the assembly of filling body, insulator plate and spring requires great manual effort

Engineering Contradiction:
Improvetemperature stabilityVSAvoidassembly complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The spring component is removed from the assembly, simplifying the structure while maintaining the filling body's function of minimizing hydraulic path volume and reducing temperature-dependent deflections.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The functions of the insulator plate (electrical insulation, positioning) and the filling body (minimizing hydraulic volume) are combined through direct compression by the liquid, eliminating the need for separate spring fastening and reducing assembly complexity.

Inventive Principle:
Principle #5Merging (Combining)

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 enables efficient minimization of the transmission liquid volume, improving the accuracy of pressure measurements by reducing temperature-dependent deflections and simplifying the assembly process, thereby enhancing the dynamic response and reliability of the pressure sensor.

Implementation Method 1

The transmission fluid has a thermal expansion coefficient that is significantly greater than the thermal expansion coefficient of the surrounding solid. This causes temperature-dependent deflections of the separating membrane

Methodology Applied
Scientific EffectThermal expansion coefficient difference: Thermal Expansion

Implementation Method 2

an insulator plate made of plastic in the converter chamber, which is prestressed against the filling body by a spring

Methodology Applied
Scientific EffectElectrical insulation: Electrical Resistance

Implementation Method 3

through the packing from the end face of four axial bores extend through which electrical connections for the semiconductor pressure transducer can be routed

Methodology Applied
Scientific EffectElectrical conduction: Conduction (electrical)

Data Source

PatentEP2401595B1Pressure sensor having a semiconductor pressure transducer
Publication Date: 2017.05.24 ENDRESS & HAUSER GMBH & CO KG
  • EP2401595B1 patent drawingFigure 1a~1c
  • EP2401595B1 patent drawingFigure 2~4

AI summary

The invention relates to a pressure sensor comprising a semiconductor pressure transducer (41) having a measuring membrane and a circuit for converting a deformation of the measuring membrane into a signal, a pressure transmitter having a hydraulic path that extends through a solid body (50) between a first and a second opening, wherein the first opening is sealed using a separating membrane that can be loaded with a pressure in order to introduce the pressure to be measured into the hydraulic path, wherein at the second opening the hydraulic path opens into a transducer chamber in which the pressure transducer (41) is arranged and that is sealed by the measuring membrane of the pressure transducer, wherein the hydraulic path contains a transmitting liquid, a filling body (11) that is arranged in the transducer chamber in order to fill up cavities between the metallic walls of the transducer chamber and the semiconductor pressure transducer, and an isolator plate that is arranged in the transducer chamber between the measuring membrane and a wall of the transducer chamber facing the measuring membrane, wherein the isolator plate (21) is fixed to the filling body or is designed as one piece with the filling body.