Capacitive sensor

Abstract

The invention discloses a capacitive sensor which is characterized in that a positioning convex ring is arranged on a ceramic insulation ring, the inner wall of a metal jacket is provided with a limiting convex ring, a high-temperature hard cable is connected with the ceramic insulation ring, a core electrode comprises a clamping ring and a connecting rod, one end of the ceramic insulation ring is provided with a clamping cavity, a high-temperature core wire in the high-temperature hard cable is fixedly connected with the connecting rod, a metal pressing sleeve is welded and fixed to a metal outer shielding layer of the high-temperature hard cable, the metal pressing sleeve is connected to the positioning convex ring in a butting mode, and the outer surface of the metal pressing sleeve is fixedly connected with the metal jacket. The capacitive sensor has the advantages that the ceramic insulation ring is fixedly clamped into the metal jacket, surface metallization is needless, a high-temperature probe is firmly connected with the hard-temperature hard cable, the situation that parts fall and a to-be-tested system is damaged can be prevented, welding is carried out between metal, and laser welding can be carried out; due to the fact that the high-temperature hard cable is matched with a low-temperature soft cable, the high-temperature-resistance characteristic can be guaranteed, cost is reduced, and on-line monitoring of the equipment is facilitated.

Description

technical field [0001] The invention relates to a sensor, especially a capacitance sensor. Background technique [0002] The high temperature capacitive sensor is a sensor used in the on-line measurement of the tip clearance of the aeroengine. Therefore, the capacitive sensor should have high sensitivity, high accuracy, air tightness, strong anti-interference and high temperature resistance (capacity 1200°C). [0003] At present, there is a capacitive sensor that metallizes the surface of the ceramic insulating ring, and then uses a brazing process to fix it with the metal jacket. It has the following shortcomings: First, metallizing the surface of the ceramic insulating ring is not only expensive , and the process is difficult, and the surface of the ceramic cannot be evenly metallized, which affects the quality of the brazing, so that good air tightness cannot be guaranteed; second, the ceramic insulating ring can only use 95 ceramics that can be metallized on the surface,...

AI Technical Summary

Problems solved by technology

[0003] At present, in a capacitive sensor, the surface of the ceramic insulating ring is metallized, and then it is fixedly connected to the metal jacket by brazing, which has the following disadvantages: First, the metallization of the ceramic insulating ring surface is not only expensive , and the process is difficult, and the surface of the ceramic cannot be evenly metallized, which affects the quality of the brazing, so that good air tightness cannot be guaranteed; second, the ceramic insulating ring can only use 95 ceramics that can be metallized on the surface, However, the capacitance value of 95 ceramics will change suddenly at 400-600°C, and the electrical insulation performance cannot be satisfied at high temperatures, so this kind of capacitance sensor cannot work in high temperature environments.

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