Compressible Seal for Waterproof Electrical Conduit Joints
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Solution Overview
Problem
Electrical conduit systems in hygienic environments, such as food and pharmaceutical industries, face challenges in maintaining a waterproof and earthed connection while being easily cleanable, as conventional sealants like PTFE tape are electrically insulating and create dirt traps, and cable glands disrupt the earth circuit.
Innovation Solution
A conduit system with an abutment member and compressible seal that applies pressure to create a seal between the conduit and junction without altering electrical resistance, using an O-ring as the compressible seal, which is externally located and does not interfere with cable movement or increase dirt traps.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealant is applied to the join between conduit and junction, then waterproofing is improved, but ease of cleaning deteriorates due to creation of dirt traps
Solution Approach 1:
The compressible seal (O-ring) is used instead of conventional sealant. This flexible ring provides effective waterproof sealing without creating the irregular surfaces and material buildup that characterize sealant applications. The smooth, contained geometry of the O-ring eliminates dirt traps while maintaining hydrodynamic sealing performance.
2Ease of operation
If stainless steel conduit system is used in hygienic environments, then ease of cleaning is improved, but sealing capability deteriorates as sealant adhesion becomes more difficult
Solution Approach 1:
The compressible seal (O-ring) provides sealing through elastic deformation rather than adhesion to the stainless steel surfaces. This eliminates the adhesion problem inherent in sealant applications to non-porous metals, while the smooth surfaces of the O-ring and stainless steel components maintain excellent cleanability characteristics.
3Adaptability or versatility
If threading die is used to create new thread on cut conduit section, then adaptability is improved, but manufacturing precision deteriorates as thread tolerance is not as good as factory-formed threads
Solution Approach 1:
The abutment member with threaded portion is designed to accommodate a range of thread tolerances. By optimizing the thread parameters (pitch, depth, profile) and providing appropriate clearance and engagement length, the connection can tolerate the wider tolerance range produced by field threading operations while maintaining secure mechanical and electrical connection.
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
Provides a highly water-resistant seal without affecting the earth circuit or increasing dirt traps, allowing for easy cleaning and retrofitting to existing systems without significant cost or size increase.
Implementation Method 1
a first surface of the abutment member and an end surface of the conduit receiving portion of the junction are adapted to engage opposing sides of the compressible seal and apply pressure to the compressible seal thereby sealing the conduit relative to the junction
Implementation Method 2
at least one compressible seal for sealing the conduit relative to the junction
Data Source
Figure 1
Figure 2
Figure 2a
AI summary
A sealing device incorporated into an electrical conduit system is disclosed. The conduit system includes lengths of conduit and a junction box for connecting the conduit lengths. The system also includes a seal that is either squeezed between the end of the conduit and a lip formed inside the junction or squeezed between the end of the connecting portion of the junction box and an abutment member that is threaded onto the conduit. In either case the seal prevents water entering the inside of the conduit system but the sealing devices make minimal changes to the internal and/or external dimensions of the conduit system.