Surge Protector Varistor Retaining Means for Thermal Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing surge protectors face issues with thermal runaway due to varistor aging, leading to increased leakage current, heat transmission to surrounding equipment, and a lack of standardization, which complicates production and increases costs.
Innovation Solution
A surge protector device with a varistor housed in a way that uses a retaining means extending between the housing and the varistor's face, creating a free space for better thermal insulation and allowing for standardized components, reducing the risk of fire and simplifying production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the varistor is directly mounted against the housing back face to simplify assembly, then the device complexity is reduced, but the heat transmitted to the housing increases the risk of fire
Solution Approach 1:
The patent introduces a retaining means as an intermediary component between the varistor and the housing back face. This retaining means includes a retention portion that contacts the varistor and a housing portion attached to the housing, creating a thermal barrier that prevents direct heat transmission while maintaining mechanical support and electrical connection functionality.
Solution Approach 2:
The retaining means is divided into distinct functional portions: a retention portion for contacting and positioning the varistor, and a housing portion for attachment to the housing. This segmentation allows the component to fulfill multiple functions (mechanical support, thermal insulation, electrical connection) while maintaining simple assembly.
2Reliability
If different housing designs are used for different varistor thicknesses to ensure proper thermal disconnection means docking, then the thermal protection function is improved, but the manufacturing complexity and cost increase
Solution Approach 1:
The retaining means serves multiple functions simultaneously: it provides mechanical retention for varistors of different thicknesses, maintains proper docking of the thermal disconnection means, and acts as a thermal barrier. This multi-functionality allows a single standardized component design to work with various varistor specifications, eliminating the need for multiple housing variants.
Solution Approach 2:
The retaining means extends in a direction substantially perpendicular to the first face of the varistor, utilizing the lateral dimension rather than relying solely on the thickness dimension. This dimensional approach allows the same component to accommodate varistors of different thicknesses while maintaining proper positioning and thermal isolation.
3Ease of manufacture
If the varistor is allowed to move freely in the housing to simplify manufacturing, then the ease of manufacture is improved, but the reliability of electrical connection and thermal protection decreases
Solution Approach 1:
The retaining means is designed to automatically position and retain the varistor in the correct location within the housing through its geometric configuration. The retention portion engages with the varistor body to provide mechanical positioning, ensuring stable electrical connection and proper alignment with the thermal disconnection means without requiring additional assembly steps or complex fixtures.
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 effectively minimizes the risk of fire during thermal runaway and standardizes the production process, reducing costs and improving safety by maintaining the varistor in position through a mechanical connection that enhances thermal insulation and allows for a variety of varistor thicknesses to be accommodated with minimal modifications.
Implementation Method 1
This increase in the leakage current generates a significant heating of the varistor by the Joule effect
Implementation Method 2
The heat given off by the varistor at the end of its life is liable to be transmitted to surrounding equipment and materials
Data Source
Figure 1~2
Figure 3~5
AI summary
The device has a varistor (4) e.g. metal-oxide varistor, arranged within a housing (3) and including two poles (9, 10) and two faces (5, 6) from which the poles extend. A position maintaining unit maintains the varistor in position within the housing. The maintaining unit extends between an end towards which the unit is connected to a case (2) and another end towards which the unit is attached to the varistor. The unit is integrated to the pole (9) and extends, between the ends, outside a free space (18) situated to the right of each face. Independent claims are also included for the following: (1) a varistor disposed within a housing of an electrical installation protecting device (2) a method of manufacturing an electrical installation protecting device (3) a method of manufacturing a varistor disposed with a housing of an electrical installation protecting device.