Rotary Feedthrough Wear Sensing With Pre-Calibrated Hall Sensor Housing
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Solution Overview
Problem
Existing rotary unions with wear sensors require complex on-site installation and calibration, which is prone to unintentional alteration by environmental influences, necessitating costly and labor-intensive maintenance.
Innovation Solution
A rotary union design with a separate Hall sensor housing that allows for pre-calibration outside the rotary union housing, featuring a sensor housing with an axial stop surface for precise positioning and a sensor cable strain relief, ensuring easy and error-free installation and robust operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the Hall sensor is installed on-site during commissioning with snap-in connection, then the wear sensor can be calibrated, but the installation becomes complex and requires qualified personnel
Solution Approach 1:
The Hall sensor is pre-calibrated in a calibration device before installation in the rotary union. The calibration device simulates the operational environment and pre-establishes the relationship between magnet position and Hall sensor output, eliminating the need for complex on-site calibration procedures while maintaining measurement accuracy
Solution Approach 2:
A calibration device serves as an intermediary between the Hall sensor and the final installation environment. This intermediate step allows precise calibration to be performed under controlled conditions, then transferred to the actual rotary union during simple installation without requiring complex on-site procedures
2Reliability
If calibration is performed during operation, then wear can be detected, but environmental influences may unintentionally alter calibration requiring maintenance
Solution Approach 1:
The Hall sensor is pre-calibrated in a controlled calibration device that eliminates environmental influences present during operational calibration. This preliminary calibration under ideal conditions creates a stable reference that remains accurate throughout operation, preventing unintentional calibration drift
Solution Approach 2:
The calibration device provides a controlled environment that cushions against environmental influences (temperature variations, vibrations, electromagnetic interference) that would otherwise affect calibration during operation. By pre-compensating for these factors, the calibration remains stable throughout the service life of the rotary union
3Ease of operation
If the sensor housing is detachably connected with snap-in lugs, then the Hall sensor can be installed, but assembly play requires post-assembly calibration
Solution Approach 1:
The Hall sensor is pre-calibrated in the calibration device before installation, accounting for any assembly play that may exist in the detachable connection. This preliminary calibration ensures that even with minor position variations from snap-in connection, the wear detection accuracy is maintained without requiring post-assembly recalibration
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
Facilitates simplified and accurate installation of the wear sensor, reducing maintenance time and costs while maintaining calibration integrity, enabling reliable wear detection throughout the rotary union's service life.
Implementation Method 1
a wear sensor which comprises a magnet (6) fixedly arranged in the sliding ring (2) and a Hall sensor (7) radially opposite the magnet (6) in the direction of the rotation axis (5) for detecting a current axial position of the magnet (6)
Data Source
Figure 1
Figure 2~3
Figure 4~5
AI summary
The invention relates to a rotary feedthrough comprising a mechanical seal with a sliding ring and a counter ring, which bear against each other under elastic pressure at a relative rotational speed to seal a sealing gap in the direction of an axis of rotation, wherein the sliding ring is axially displaceable along the axis of rotation in the direction of the counter ring to compensate for wear in the sealing gap; with a wear sensor comprising a magnet fixedly arranged in the sliding ring and a Hall sensor radially opposite the magnet to the axis of rotation for detecting the current axial position of the magnet; with a rotary feedthrough housing and a shaft rotatably mounted about the axis of rotation in the rotary feedthrough housing; with a channel carrying a medium, which extends through the rotary feedthrough housing and the shaft and is sealed against an environment by means of the mechanical seal;wherein the Hall sensor is arranged in the rotary feedthrough housing and comprises its own sensor housing. The rotary feedthrough according to the invention is characterized in that the sensor housing is mounted in the rotary feedthrough housing, wherein the sensor housing encloses a Hall sensor with electrical connection pins, as well as a section of a sensor cable which is electrically contacted with the connection pins inside the sensor housing, and the sensor housing comprises an axial stop surface abutting in the direction of the axis of rotation in the rotary feedthrough housing, with which an axial position of the sensor housing in the rotary feedthrough housing in the direction of the axis of rotation is defined.