Pressure Sensor Sleeve Sealing Eliminates Force Shunts

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Solution Overview

Problem

Existing pressure sensors face challenges in measuring high pressures above 1000 bar with high sensitivity and accuracy due to force shunts caused by welded joints in the annular diaphragm, which also lead to oscillations and complex, costly production processes.

Innovation Solution

The pressure sensor employs a sleeve with a sealing element that seals the gap between the plunger and housing through compression, eliminating force shunts and preventing medium penetration, while using a toroidal sealing element made of elastic material to maintain sensitivity and accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a welded annular diaphragm is used to seal the gap between housing and plunger, then the gap is sealed and medium penetration is prevented, but force shunts are created that reduce measurement sensitivity and accuracy

Engineering Contradiction:
Improvegap sealing reliabilityVSAvoidpressure measurement sensitivity
Core Design Contradiction:
ReliabilityVSMeasurement precision

Solution Approach 1:

The harmful welded joint is completely removed from the system. Instead of using a welded annular diaphragm that creates force shunts, the patent extracts the sealing function and implements it separately through a compressible sealing element that contacts only the plunger surface, eliminating the force shunt path while maintaining gap sealing reliability.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

A compressible sealing element is introduced as an intermediary between the plunger and housing. This sealing element mediates the sealing function by being compressed against the plunger surface to prevent medium penetration, while its compliant nature avoids creating rigid force shunts that would reduce measurement sensitivity.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Duration of action of stationary object

If a thick annular diaphragm is used to ensure long service life at high pressures, then durability is improved, but force shunt effects are amplified and measurement sensitivity decreases

Engineering Contradiction:
Improveservice lifeVSAvoidpressure measurement sensitivity
Core Design Contradiction:
Duration of action of stationary objectVSMeasurement precision

Solution Approach 1:

The sealing element is designed as a simpler, replaceable component with a groove for insertion. Rather than making the critical diaphragm thicker and more complex to handle high pressures, the patent uses a dedicated sealing element that can be easily replaced if worn, maintaining measurement sensitivity while ensuring long service life through component replaceability.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If a welded annular diaphragm is used to seal the gap, then medium penetration is prevented, but the welded joint creates an oscillating system that distorts pressure measurement

Engineering Contradiction:
Improvegap sealing reliabilityVSAvoidmeasurement distortion from vibrations
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The rigid welded annular diaphragm is replaced with a flexible compressible sealing element made of elastomeric or plastic material. This flexible sealing element conforms to the plunger surface and prevents medium penetration without creating rigid oscillating structures that would generate vibrations and distort pressure measurements.

Inventive Principle:
Principle #30Flexible shells and thin films

4Reliability

If a welded joint is used to attach the annular diaphragm in the gap, then sealing is achieved, but the production process becomes complex and expensive due to difficult access for welding tools

Engineering Contradiction:
Improvegap sealing reliabilityVSAvoidproduction complexity
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The sealing function is segmented from the structural diaphragm. Instead of welding a diaphragm to both housing and plunger in a complex joint, the sealing element is separated as an independent component with a groove for insertion, allowing simple compression-based assembly without requiring complex welding operations in difficult-to-reach locations.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The sealing element is pre-formed with a groove structure that allows it to be compressed into place during assembly. This preliminary preparation of the sealing element with its insertion groove enables simple compression-based installation without requiring complex welding tools or operations, significantly simplifying the manufacturing process.

Inventive Principle:
Principle #10Preliminary action

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 design achieves high sensitivity and accuracy in pressure measurement, even at high pressures, by ensuring that nearly all pressure is transferred to the measuring element, while also simplifying and cost-reducing the production process.

Implementation Method 1

at least one sealing element, which sealing element seals the gap for the medium to the housing interior by means of sealing compression

Methodology Applied
Scientific EffectCompression: Compression

Implementation Method 2

a toroidal sealing element made of elastic material

Methodology Applied
Scientific EffectElasticity: Elasticity

Data Source

PatentEP4556872A1Pressure sensor and method for the production thereof
Publication Date: 2025.05.21 KISTLER HLDG AG
  • EP4556872A1 patent drawingFigure 1
  • EP4556872A1 patent drawingFigure 2
  • EP4556872A1 patent drawingFigure 3

AI summary

The invention relates to a pressure sensor (1) comprising a housing (20), a stamp unit (11), and a measuring element (12); which housing (20) has a housing interior (20.3), and which stamp unit (11) and which measuring element (12) are arranged in the housing interior (20.3); which stamp unit (11) has a distal stamp end (11.1) and a proximal stamp end (11.2), which distal stamp end (11.1) is arranged on a longitudinal axis (A) of the pressure sensor (1) further away from the measuring element (12) than the proximal stamp end (11.2), which distal stamp end (11.1) protrudes from the housing (20) and which proximal stamp end (11.2) is operatively connected to the measuring element (12) and transmits a pressure (P) of a medium (M) prevailing outside the housing (20) to the measuring element (12); wherein the pressure sensor (1) has a sleeve (30), which sleeve (30) is fastened to the housing (20); wherein the sleeve (30) and the distal stamp end (11.1) are spaced apart from one another by a gap (30.4); and wherein the pressure sensor (1) has at least one sealing element (40), which sealing element (40) seals the gap (30.4) for the medium (M) to the housing interior (20.3) by means of sealing compression.