Hazardous-Area Cable Gland With Single-Nut Sealing and Venting
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Solution Overview
Problem
Conventional cable glands for explosion-proof enclosures in hazardous locations are complex three-piece assemblies that require time-consuming assembly and tracking of multiple parts, increasing installation time and complexity.
Innovation Solution
A simplified cable gland design with fewer parts, featuring a hub body, gland nut, seal, ring, and spring, which allows for quick assembly by torquing a single gland nut to secure the cable and create a labyrinth joint for gas dissipation, using a coiled wire spring for grounding and retention, and a labyrinth joint for safe gas release.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional three-piece cable gland assemblies are used to provide strain relief and sealing in explosion-proof enclosures, then reliability and sealing performance are improved, but device complexity and installation time increase
Solution Approach 1:
The patent combines multiple separate components (gland body, seal, strain relief elements, and explosion venting features) into a single integrated cable gland assembly. The hub body incorporates internal cavities, annular steps, and integrated seal retention features that previously required separate parts, thereby reducing part count while maintaining sealing and strain relief functionality.
Solution Approach 2:
The hub body is designed to perform multiple functions simultaneously: it provides structural support, retains the seal through integrated annular steps, provides strain relief through its geometry, and enables explosion venting through internal pressure relief features. This multi-functionality eliminates the need for separate components for each function.
2Reliability
If conventional three-piece cable gland assemblies are used to ensure proper cable attachment, then reliability is improved, but installation time and ease of operation worsen
Solution Approach 1:
The seal is pre-positioned within the hub body in a ready-to-install configuration, with retention features already formed. The hub body is pre-assembled with internal components in the correct positions, eliminating the need for users to assemble multiple parts during installation. The cable gland can be installed as a single unit, significantly reducing installation time while maintaining secure cable attachment.
3Adaptability or versatility
If conventional cable glands require multiple parts to be catalog and tracked, then adaptability is improved, but ease of operation and productivity worsen
Solution Approach 1:
The hub body is designed with adjustable parameters such as the size of the cable opening, the dimensions of annular steps, and the geometry of strain relief features that can be modified to accommodate different cable sizes. This allows a single integrated design to provide adaptability for various cable diameters without requiring multiple specialized components, thereby maintaining versatility while improving installation efficiency.
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 design reduces installation time and complexity while providing effective strain relief, sealing, and safe gas dissipation in hazardous environments, ensuring quick and secure cable attachment and gas management.
Implementation Method 1
A spring is disposed in the inner cavity between the second surface of the ring and an opposite-facing frustoconical surface fixed in the inner cavity
Implementation Method 2
the seal is compressed by the first inner annular step and the first surface of the ring and deflected radially inward
Data Source
AI summary
A cable gland for use in a hazardous environment that includes a hub body having an opening extending therethrough. A gland nut is configured to engage an end of the hub body to define an inner cavity. The gland nut has a first inner annular step and a second inner annular step. A seal, ring and spring are disposed in the inner cavity. The spring is disposed in the inner cavity between a surface of the ring and an opposite-facing frustoconical surface. When the gland nut is in a first position, the first inner annular step engages the first end of the seal. When the gland nut is in a second position, the second inner annular step engages the ring and the seal is deflected radially inward. When the gland nut is in a third position, the spring is deflected radially inward.