Liquid-Tight Conduit Fitting with Rotatable Grounding Ring
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Solution Overview
Problem
Existing conduit fittings struggle to provide a reliable, liquid-tight seal and secure grounding in harsh environments, such as wet or corrosive conditions, while allowing easy installation of ground wires.
Innovation Solution
A liquid-tight conduit fitting with a resilient PVC coating, a mating gland nut, and a rotatable grounding ring that engages with the fitting body and gland nut, allowing for easy ground wire connection and securing a liquid-tight seal upon tightening.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional conduit fitting is used, then the installation process is simple, but the liquid-tight seal reliability is insufficient in harsh environments
Solution Approach 1:
The fitting employs a composite structure combining a resilient coating material (such as rubber or elastomer) with a rigid fitting body. The resilient coating is applied to the inner surface of the fitting body, creating a composite structure that provides both structural integrity and flexible sealing capability. This allows the fitting to maintain a reliable liquid-tight seal in harsh environments while managing the complexity through material composition rather than mechanical complexity.
2Ease of operation
If the grounding ring is made rotatable for easy wire installation, then the ease of operation improves, but the risk of rotation during tightening increases
Solution Approach 1:
The grounding ring is designed to be rotatable during the preliminary stages of installation, allowing easy positioning and ground wire attachment. However, the design incorporates a mechanism where the ring becomes fixed once the fitting is fully assembled and tightened. This preliminary freedom of movement followed by final fixation resolves the contradiction by providing ease of operation when needed while ensuring seal integrity when required.
Solution Approach 2:
The grounding ring transitions from a dynamic (rotatable) state during installation to a static (fixed) state during operation. The rotatability is maintained only during the assembly process to facilitate easy ground wire installation, while the final tightened state ensures the ring remains fixed to maintain seal integrity. This dynamic design allows the same component to serve different functional requirements at different stages.
3Ease of repair
If the fitting is designed for easy disassembly, then the ease of repair improves, but the liquid-tight seal reliability may be compromised
Solution Approach 1:
The fitting is designed as a segmented, modular structure that can be easily disassembled into separate components for repair and maintenance. The resilient coating is applied in a way that allows the fitting to be taken apart and reassembled while maintaining the liquid-tight seal. This segmentation enables easy repair while preserving seal reliability through proper design of the modular interfaces and coating application.
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 ensures a secure, liquid-tight seal and easy ground wire installation, even in challenging environments, by compressively engaging the grounding ring between the coating layers, preventing rotation and maintaining a watertight seal.
Implementation Method 1
compressively engaging the grounding ring between the coating layers
Implementation Method 2
resilient PVC coating
Data Source
AI summary
A method for installing a conduit in a liquid-tight fitting includes inserting a coated gland nut configured for insertion onto a conduit, wherein the gland nut includes an outer surface and internal threads. A grounding ring is placed onto external threads of a tubular fitting body having a coated intermediate portion, such that an inner surface of the grounding ring is conductively coupled to the external threads of the fitting body. The outer surface of the grounding ring includes a ground wire engaging portion projecting therefrom. The internal threads of the gland nut are loosely coupled to the external threads of the fitting body. The grounding ring is rotated to a desired position relative to the fitting body. The gland nut is tightened to the fitting body, such that the coated outer surface of the gland nut and the coated intermediate portion of the fitting body compressingly engage the grounding ring therebetween.