Temperature Sensor Seal Members Prevent Leakage Current
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Solution Overview
Problem
Temperature sensors face reduced accuracy due to moisture absorption by the insulator in the sheath member, especially in high-temperature environments, leading to lower insulation resistance and potential leakage current paths.
Innovation Solution
Incorporating seal members with insulation resistance equal to or greater than the covering member, primarily made of glass or water-repellent ceramics, to prevent water absorption and leakage current formation, while using magnesia for the insulator to maintain accurate sensing of the temperature-sensitive element's electrical properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If seal members are disposed to block water permeation at the ends of the cladding member, then moisture absorption by the insulator is suppressed, but the seal members form leakage current paths in high-temperature environments due to reduced insulation resistance
Solution Approach 1:
The patent changes the material parameter of the seal members from conventional materials to glass or water-repellent ceramic materials that maintain high insulation resistance even at elevated temperatures. This material parameter change allows the seal members to simultaneously provide effective moisture blocking and maintain electrical insulation, preventing leakage current paths while protecting against moisture absorption by the insulator.
Solution Approach 2:
The patent employs composite material solutions by using glass materials or water-repellent ceramic materials for the seal members. These materials combine moisture-blocking properties with high-temperature insulation characteristics, creating a composite functional structure that addresses both moisture protection and electrical insulation requirements in high-temperature environments.
2Reliability
If the insulator is made of magnesia to maintain insulation properties, then moisture absorption reduces insulation resistance, but accuracy of temperature sensing deteriorates
Solution Approach 1:
The patent introduces glass seal members as intermediary elements that seal the interface between the magnesia insulator and the external environment. These glass seal members act as a protective barrier that prevents moisture from reaching the magnesia insulator, thereby maintaining the insulator's electrical properties and ensuring accurate temperature sensing without compromising insulation performance.
Solution Approach 2:
The patent applies parameter changes by selecting glass or water-repellent ceramic materials for the seal members that have both low water absorption and high insulation resistance at operating temperatures. This material selection changes the moisture absorption parameter of the overall structure, protecting the magnesia insulator from moisture while maintaining sensing accuracy.
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 restricts moisture absorption and leakage current paths, ensuring accurate sensing of the temperature-sensitive element's electrical properties even in high-temperature environments, maintaining the insulation resistance and preventing a reduction in temperature sensing accuracy.
Implementation Method 1
seal members formed mainly of glass and surrounding or covering a junction between the conductor and the temperature sensitive element or a junction between the another member and the temperature sensitive element. The seal members are formed so as to have an insulation resistance equal to or greater than that of the covering member.
Implementation Method 2
a covering member formed mainly of glass and surrounding or covering a junction between the conductor and the temperature sensitive element or a junction between the another member and the temperature sensitive element
Implementation Method 3
Examples of the temperature sensitive element include an element including a metallic or platinum resistor whose electrical property (electric resistance) changes with temperature, and a thermistor element including a conductive oxide sintered body whose electrical property (electric resistance) changes with temperature.
Data Source
AI summary
In a temperature sensor, two seal members seal the open opposite ends of a cladding member (a forward end and a rear end), so that water absorption by an insulator of a sheath member can be restrained. The seal members are formed to have an insulation resistance equal to that of a conductor-fixing material. Therefore, even when the temperature sensor is used in a high-temperature environment, the insulation performance of the seal members does not become lower than the insulation performance of the conductor-fixing material, so that the formation of a leakage current path can be suppressed. According to the temperature sensor, the electrical property of a temperature sensitive element can be sensed accurately, and a reduction in the accuracy of temperature sensing can be restrained.