External Strain-Gauge Connecting Piece for Aggressive-Media Pressure Sensing
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Solution Overview
Problem
Conventional pressure sensors for hydraulic systems face issues such as reduced service life due to aggressive media compatibility, flow turbulence causing cavitation and maintenance frequency, and high design and space requirements, especially when dealing with high pressures like hydrogen.
Innovation Solution
A connecting piece with strain gauges arranged circumferentially on the outer wall of the fluid channel, measuring expansion to determine pressure without direct contact with the medium, using a Wheatstone full bridge circuit for compensation and wireless or inductive connection to a control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional pressure sensors with sensitive membranes are used in hydraulic systems, then pressure measurement is achieved, but media compatibility is limited and service life is reduced due to aggressive media like hydrogen
Solution Approach 1:
A magnetic coupling mechanism acts as an intermediary between the measurement system and the fluid medium. The strain gauges measure deformation of the connecting piece wall caused by internal pressure, and this deformation is transmitted through the wall material to affect a magnet on the outside. A corresponding magnet on the sensor housing detects the position changes without the sensor components needing to contact the aggressive medium, thereby extending service life while maintaining measurement capability across different media
Solution Approach 2:
The patent replaces direct mechanical contact between the sensor and the fluid medium with a magnetic field-based measurement system. Instead of using a membrane that physically contacts the aggressive medium, the system uses strain gauges embedded in the connecting piece wall that detect pressure-induced deformation mechanically, then transmit this information magnetically to external sensors, eliminating the need for media-compatible sensitive membranes
2Reliability
If T-connector branches are used for pressure measurement, then pressure monitoring is enabled, but flow turbulence and cavitation occur causing flow losses and increased maintenance
Solution Approach 1:
The pressure measurement function is merged directly into the connecting piece structure itself. The connecting piece incorporates strain gauges in its wall that directly measure the pressure of the medium flowing through it, eliminating the need for separate T-connector branches. This integration allows pressure monitoring while maintaining smooth fluid flow through the connecting piece, avoiding turbulence and cavitation associated with branch connections
3Measurement precision
If conventional pressure sensors are used in high-pressure systems, then pressure measurement is achieved, but design effort and space requirements increase
Solution Approach 1:
The connecting piece serves multiple functions: it connects fluid conduits, contains the fluid medium under pressure, and simultaneously acts as the measurement element for pressure detection through embedded strain gauges. This multi-functionality eliminates the need for separate sensor housings, mounting structures, and connection components, thereby reducing design complexity and space requirements while maintaining high-pressure measurement capability
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 reliable pressure measurement in high-pressure systems with extended service life, reduced maintenance, and media versatility, including aggressive media like hydrogen, with reduced flow losses and space requirements.
Implementation Method 1
at least two strain gauges (12) arranged offset on the circumference around a fluid channel axis (X) on an outer wall (14) of the measuring section (10) for measuring an expansion of the connecting piece (1)
Implementation Method 2
using a Wheatstone full bridge circuit for compensation
Data Source
Figure 1
Figure 2~4
Figure 5~6
AI summary
The invention relates to a connecting piece (1) for fluid-conducting line systems, having a fluid channel (2) running along a fluid channel axis (X). The fluid channel (2) can be connected to line channels of the line system at at least one first connection end (4) and a second connection end (6) of the connecting piece (1). A measuring section (10) in which a sensor system is arranged for measuring the pressure of a medium flowing in the fluid channel (2) is arranged between the first connection end (4) and the second connection end (6). The sensor system has a connection interface, by means of which the sensor system can be connected to a control unit for measuring the pressure in the fluid channel (2), and at least two elongation measuring sensors, which are arranged on an outer wall (14) of the measuring section (10) in an offset manner on the circumference about the fluid channel axis (X), in order to measure the pressure. The invention additionally relates to a control unit for connecting to the sensor system in order to measure the fluid pressure in the aforementioned connecting piece (1), comprising connection means for connecting to the sensor system of the connecting piece (1) so as to transmit data and computing means for computing the fluid pressure in the connecting piece (1) using received data and using line- and/or medium-specific parameters stored in the control unit.