Flexible Membrane Gland Plate for Cable Sealing
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Solution Overview
Problem
Current gland plates for switchboards face limitations in accommodating cables of different sizes without compromising ingress protection (IP30), require cumbersome cutouts, and fail to maintain protection when cables are removed, with existing seals lacking sufficient strength and resilience.
Innovation Solution
A flexible membrane gland plate with a sandwich structure of closed cell thermoplastic rubber between thermoplastic foam layers, reinforced with glass fibre reinforced plastic (GFRP) laminates, providing high tear strength, compression resistance, and flame retardancy, along with guiding pins for easy cable insertion and no need for additional sealing upon cable removal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If predefined cutouts or guide ways are used in traditional gland plates, then cable passage is enabled, but the same cutout locations cannot be reused for cables of different sizes while maintaining IP30 protection
Solution Approach 1:
The patent employs a flexible membrane made of elastomeric material that can be deformed to accommodate cables of varying diameters. The membrane's elasticity allows it to stretch around larger cables and compress around smaller cables, maintaining IP30 protection in both scenarios without requiring different cutout configurations.
Solution Approach 2:
The membrane's physical state changes dynamically - it deforms elastically to adapt its shape and size according to the cable diameter. This parameter change allows a single cutout location to serve multiple cable sizes while maintaining the sealing integrity required for IP30 protection.
2Ease of operation
If cutouts are made in plastic or sheet metal gland plates, then cables can be passed through preferred locations, but the process becomes cumbersome and requires additional tools
Solution Approach 1:
The flexible membrane eliminates the need for cutting operations entirely. Installers simply insert cables through pre-formed openings in the membrane, which then seal around the cables automatically. This removes the cumbersome cutting step while maintaining the ability to pass cables through preferred locations.
3Adaptability or versatility
If cables are removed from traditional gland plates, then configuration changes are enabled, but holes must be plugged to maintain IP protection
Solution Approach 1:
The flexible membrane automatically returns to its original sealed state when a cable is removed, eliminating the need for separate plugging operations. The membrane's elastic recovery property ensures IP protection is maintained without requiring additional sealing components or complex procedures.
Solution Approach 2:
The membrane performs the sealing function automatically through its elastic properties. When a cable is inserted, the membrane deforms to seal around it; when removed, it automatically returns to its sealed state. This self-service mechanism eliminates the need for manual intervention to maintain IP protection during configuration changes.
4Reliability
If self-sealing materials like silicone rubber are used, then aperture sealing is achieved, but tear strength and compression resistance are insufficient for IP30 protection
Solution Approach 1:
The patent uses a composite structure where an elastomeric membrane (providing sealing capability) is sandwiched between two rigid plates (providing structural strength). This composite construction combines the sealing properties of elastomers with the mechanical strength of rigid materials, achieving both IP30 protection and sufficient tear/compression resistance.
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
Enables the passage of cables of varying diameters through the same cutouts while maintaining IP30 protection, preventing foreign object ingress, and ensuring no additional sealing is required after cable removal, with enhanced mechanical and thermal properties.
Implementation Method 1
a flexible membrane gland plate, e.g. 15 to 20mm thick, comprising a core layer, preferably 4 to 6mm thick, of closed cell thermoplastic rubber
Implementation Method 2
comprising a core layer, preferably 4 to 6mm thick, of closed cell thermoplastic rubber sandwiched between top and bottom layers of thermoplastic foam
Implementation Method 3
The right combination of constituents of the foam sandwich is optimized for the critical mechanical and thermal properties; in particular, density, tear strength, indentation force, resilience, compression set, hardness and flammability are selected
Data Source
AI summary
A flexible membrane gland plate (10) is developed in a sandwiched structure so as to prevent holes to be formed by insertion of cables (42), and to allow IP30 to be kept when cables (42) are removed. The gland plate (10) comprises a core layer (12) and a top and a bottom sandwiching layers (14), the composition of which is selected for the desired purpose; the gland plate (10) may be sandwiched with reinforcing material so as to be used as top wall for an electric enclosure (40). A flexible membrane gland plate (10) according to this invention comprises a layer (12) of RoHS compliant and flexible foam of ethylene vinyl acetate copolymer with fire retardant fillers, which is sandwiched between two layers (14) of nitrile foam. The outer two layers are composed by closed cell nitrile foams, which are oriented with its grain directions mutually perpendicular to each other such as to achieve better compressibility in the direction opposite the grain direction during insertion of the cable (42) onto the gland plate (10). Another flexible membrane gland plate (20) comprises a close celled cross linked polyethylene foam (22) as the core material and polyurethane foam (24) of density 170 kg/m3 as the outer two stratums; a thin film of micro porous polyurethane film (26) is bonded on the exposed area of PU foam by a process of hot lamination at 160°C.