Wide frequency response noise resistant adapterization probe adopting double piezoelectric ceramic wafers

Abstract

The invention relates to a vibration probe for detecting breaking points of a cable and a pressure pipeline, which mainly comprises an outer shell, a mandrel, an inner shield, an inner cover, a circuit board, a carrying handle, an aviation socket, a piezoelectric wafer and a base, wherein the circuit board is provided with an impedance conversion amplifying circuit containing two piezoelectric ceramic wafers with different inherent frequency Omega n and a summator; the inner shield is fixed on the outer shell; the base is fixedly connected with the inner shield by the mandrel; the piezoelectric wafer is installed on the mandrel; the inner cover is fixed on the inner shield; and the circuit board is fixed on the inner cover. The outer shell is formed by casting rubber, and the inner shieldis made of nylon plastics. The adapterization probe of the piezoelectric ceramic wafers has wider frequency response range and more favorable effect of insulating sound in the air. A test proves thatthe output frequency range of the adapterization probe is obviously improved after the adapterization probe is adopted; compared with a single piezoelectric wafer probe, the output frequency range can be doubled approximately, and simultaneously, the interference on the sound in the air can be improved by 10-20db.

Description

technical field [0001] The invention relates to a probe, in particular to a vibrating probe for detecting damaged points of cables and pressure pipes. Background technique [0002] The detection of the fault and damage point location of cables and pressure pipes is carried out by means of detecting vibration sound on the ground or on the pipeline. The equipment commonly used in this detection method is composed of a pickup probe, signal amplification processing equipment and earphones. The pickup probe is an acoustic-electric sensor, which is located at the front end of the device and has the function of completing the acoustic-electric conversion. It is a key component; the signal amplification processing equipment further processes the electrical signal obtained by the probe by amplifying, filtering, and displaying, and finally outputs it to the earphone , for manual discrimination. [0003] Commonly used pickup probes are mainly composed of a mandrel, an inner cover, a ...

AI Technical Summary

Problems solved by technology

Each specification of piezoelectric ceramic sheet corresponds to an inherent frequency response characteristic, that is, it is highly sensitive to sound signals in a narrow frequency range, and the sensitivity drops rapidly when leaving this frequency band

Due to the differences in the conditions of buried pipelines underground, the main frequency of the vibration sound from the ground sometimes deviates from the frequency range with high sensitivity of the piezoelectric ceramic sheet, resulting in a decrease in detection sensitivity

[0004] The actual situation is often: there will be various interference sounds at the detection site directly transmitted from the air to the shell and handle of the pickup probe, and then transmitted from the structural parts to the piezoelectric ceramic sheet. Detection effect of ground vibration sound

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