Resistance wire abnormality detection device

Patent metadata

Field	Value
Publication number	US-12298358-B2
Application number	US-202118016354-A
Country	US
Kind code	B2
Filing date	Jul 28, 2021
Priority date	Jul 28, 2021
Publication date	May 13, 2025
Grant date	May 13, 2025

Abstract

An electric circuit abnormality detection device includes a pulse generator, a directional coupler, and a detection unit. The detection unit includes a reference reflected wave database and a calculation part. The reference reflected wave database stores waveform information of a reference reflected wave inputted from the directional coupler when a pulse signal is inputted to a reference electric circuit that has a same wiring pattern as a pulse heater and does not have an abnormality. The calculation part detects an abnormality in the pulse heater by comparing waveform information of a reflected wave inputted from the directional coupler when the pulse signal is inputted to the pulse heater, with waveform information of the reference reflected wave stored in the reference reflected wave database.

First claim

What is claimed is:

1. A resistance wire abnormality detection device for detecting abnormality in a resistance wire having a plurality of bends, the resistance wire abnormality detection device comprising:
a pulse generator which inputs a pulse signal to the resistance wire;
a directional coupler which is provided between connection lines connecting between the resistance wire and the pulse generator and extracts, from the plurality of bends of the resistance wire, a composite reflected wave in which a plurality of individual reflected waves of the pulse signal inputted from the pulse generator to the resistance wire are superimposed;
a low-pass filter which is connected to the directional coupler and removes high-frequency noise from the composite reflected wave inputted from the directional coupler to output a reflected wave for detection;
a detection unit which is connected to the low-pass filter and processes the reflected wave for detection inputted from the low-pass filter to detect an abnormality in the resistance wire; and
wherein the detection unit comprises:
a storage part which stores waveform information of a reference reflected wave inputted from the directional coupler when the pulse signal is inputted to the resistance wire that has a same shape as the the resistance wire and does not have an abnormality; and
a calculation part which detects an abnormality in the resistance wire by comparing waveform information of the reflected wave for detection inputted from the directional coupler when the pulse signal is inputted to the resistance wire, with waveform information of the reference reflected wave stored in the storage part,
wherein the calculation part detects an abnormality in the resistance wire when a difference between a magnitude of the reflected wave for detection and a magnitude of the reference reflected wave exceeds a first range that is predetermined,
detects a complete disconnection in the resistance wire when the difference between the magnitude of the reflected wave for detection and the magnitude of the reference reflected wave exceeds a second range which is larger than the first range, and
detects a partial disconnection in the resistance wire when the difference between the magnitude of the reflected wave for detection and the magnitude of the reference reflected wave exceeds the first range but is smaller than the second range.

Assignees

• Shinkawa Kk

Inventors

• Kikuchi Hiroshi
• Fukumoto Shinsuke

Classifications

• G01R23/165

  using filters · CPC title

• G01R23/005

  Circuits for comparing several input signals and for indicating the result of this comparison, e.g. equal, different, greater, smaller (comparing phase or frequency of 2 mutually independent oscillations in demodulators) · CPC title

• G01R29/027

  Indicating that a pulse characteristic is either above or below a predetermined value or within or beyond a predetermined range of values · CPC title

• G01R31/58 Primary

  Testing of lines, cables or conductors (testing of electric windings G01R31/72) · CPC title

• G01R31/52

  Testing for short-circuits, leakage current or ground faults · CPC title