Explosive Atmosphere Lead-in Bushing with Preformed Elastomeric Seal
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Solution Overview
Problem
Existing lead-in bushings for explosive atmospheres require an additional work phase to fill free space with liquid resin, are difficult to disassemble, and may have non-uniform resin filling, leading to potential defects in passing aging or pressure tests.
Innovation Solution
A lead-in bushing with a solid inlet seal made of elastomeric material, such as silicone rubber, that is preformed with passages for cables and protected by metallic collars, allowing for secure, one-phase assembly and easy disassembly, while ensuring uniformity and pressure tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If liquid resin is injected into the bushing to fill the free space, then the bushing achieves sealing and structural integrity, but an extra work phase is required and the process becomes complex
Solution Approach 1:
The patent removes the liquid resin filling step from the manufacturing process by using a pre-formed solid inlet seal component that already contains the necessary sealing properties and structural integrity, eliminating the extra work phase while maintaining reliability
Solution Approach 2:
The inlet seal is pre-formed with passages and sealing characteristics before installation, so that the sealing function is already prepared in advance rather than requiring liquid resin injection and hardening during assembly
2Reliability
If liquid resin is used to fill the free space, then sealing is achieved, but disassembly becomes impossible without damaging the bushing
Solution Approach 1:
The inlet seal is designed as a separate, removable component that can be independently installed and removed from the bushing, allowing disassembly and modification without damaging the bushing structure while maintaining sealing integrity through the seal design
3Manufacturing precision
If liquid resin is injected into the bushing, then the free space is filled, but non-uniform filling and defects such as voids may occur
Solution Approach 1:
The patent uses a pre-formed solid inlet seal component instead of liquid resin, eliminating the risk of non-uniform filling and void defects while ensuring consistent manufacturing quality and reliable test results
4Productivity
If the inlet seal is made of elastomeric material with preformed passages, then assembly is simplified to one phase, but the structure becomes more complex
Solution Approach 1:
The inlet seal integrates multiple functions (sealing, cable guidance through passages, and structural support) into a single component, simplifying assembly to one phase while the internal passage structure provides the necessary complexity for cable routing
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 provides a secure, uniform, and pressure-tolerant lead-in bushing that can pass strict tests, with the ability to modify accessories and protect cables from sharp edges, ensuring safe sealing over a wide temperature range.
Implementation Method 1
The inlet seal is made of a material which comprises at least one elastomer. In use the inlet seal presses against the inner wall of the bushing and towards the cables, thus tightening the interface between the inner wall and the seal and the interface between each cable and the seal.
Data Source
Figure 1a~1c
Figure 2a
Figure 2b~2d
AI summary
The present invention relates to a lead-in bushing (1) for explosive atmospheres comprising a bushing (2) having a first end (18) and a second end (19), an inlet seal (3) having a front end (20) and a back end (21) inside the bushing (1) and a fastening device. The inlet seal (3) is a solid provided with preformed passages (10) for receiving cables. The present invention also relates to an electric motor.