Explosion-Proof Position Sensor Housing Segmentation
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Solution Overview
Problem
Existing position sensors using the measuring cable principle face challenges in being pressure-resistant and explosion-proof, particularly due to the risk of sparks from electrical components and inadequate sealing, which limits their use in hazardous environments.
Innovation Solution
The design incorporates a pressure-resistant encapsulation with flameproof gaps and a stable housing structure to prevent spark penetration, using stainless steel and plastic coatings to avoid metal-to-metal friction, and contactless data transmission to ensure explosion-proof operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical components are used in the position sensor, then the sensor can perform measurement and evaluation functions, but sparks may form creating explosion risk
Solution Approach 1:
The housing is divided into a pressure-tight first housing part containing electrical components (angle sensor, evaluation electronics) and a non-pressure-tight second housing part containing the cable drum. This segmentation isolates spark-generating electrical components from the explosive atmosphere while maintaining measurement functionality.
Solution Approach 2:
A magnetically coupled transmission system acts as an intermediary between the pressure-tight and non-pressure-tight housing parts. The first shaft with magnets in the pressure-tight part couples magnetically to the second shaft with magnets in the non-pressure-tight part, enabling signal transmission without physical penetration that could allow spark escape.
2Reliability
If the housing is made pressure-tight to prevent spark penetration, then explosion protection is improved, but the measuring cable cannot be fed through to the outside
Solution Approach 1:
The housing is segmented into pressure-tight and non-pressure-tight sections, allowing the measuring cable to access the non-pressure-tight second housing part and exit through the second housing part without compromising the pressure-tight seal of the first housing part containing electrical components.
Solution Approach 2:
The measuring cable and cable drum are extracted from the pressure-tight housing part and placed in the non-pressure-tight second housing part. This extraction allows cable access and measurement functionality while isolating the cable system from the explosion-proof enclosure.
3Reliability
If stainless steel components are used to prevent sparking, then explosion protection is improved, but metal-to-metal friction may still occur
Solution Approach 1:
The cable drum is constructed as a composite structure with a plastic drum body and a separately rotatable stainless steel bottom. The plastic material prevents metal-to-metal friction and sparking, while the stainless steel bottom provides corrosion resistance and structural integrity without direct friction contact.
4Reliability
If the annular gap around the measuring wire is made long relative to width for flameproof security, then explosion protection is improved, but the wire inlet structure becomes more complex
Solution Approach 1:
The wire inlet tower extends axially (in the longitudinal dimension) rather than increasing radial complexity. The annular gap lengthens in the axial direction, providing flameproof security through increased gap length relative to width without adding complex radial or angular structural elements.
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 achieves a pressure-resistant and explosion-proof position sensor that can operate safely in hazardous environments by preventing spark formation and maintaining flameproof security, even under high overpressure conditions.
Implementation Method 1
the first shaft (7) is magnetically coupled to the second shaft (7)
Implementation Method 2
the housing is designed in such a way that in this case, too, no flammable Sparks can penetrate the housing to the outside because the existing gaps in the housing are flameproof
Data Source
Figure 1
Figure 2a~2c
Figure 3
AI summary
An explosion proof position sensor has a shaft (7) joining a flat spiral spring (4) and angle encoder (5) in an external pressure proof housing (6a) with measurement cable drum (2) in an unsealed housing (6b). Independent claims are included for assemlby procedures used in constructing the position sensor.