An ultrasonic sensor for a flow meter

Abstract

The invention relates to an ultrasonic wave sensor for a flowmeter. The ultrasonic wave sensor comprises a piezoelectric element consisting of a piezoelectric module and a virtual piezoelectric element module, a shell, a base, a sound emitting surface grounding electrode, a side face grounding electrode, a back grounding electrode, a driving electrode, a grounding electrode lead, a driving electrode lead, a grounding electrode terminal and a driving electrode terminal. A working principle is that ultrasonic wave sensors are arranged on the upstream and the downstream of a fluid passage with a specified sectional area respectively, one of the ultrasonic wave sensors on the upstream and the downstream emits ultrasonic waves, the other receives the ultrasonic waves, the two ultrasonic wave sensors alternately work, and the ultrasonic waves are overlapped with fluid velocity when the ultrasonic waves are transmitted forwards and backwards, so that time difference exits between the forward ultrasonic wave transmission time and the backward ultrasonic wave transmission time, and the fluid velocity can be calculated sequentially. Compared with the prior art, the ultrasonic wave sensor has the advantages that asymmetry of an ultrasonic wave receiving sensitivity characteristic is improved by adjusting the intensity distribution of the ultrasonic waves output by the piezoelectric element, a signal to noise ratio (S / N) of an ultrasonic flowmeter inspection signal can be improved and the flow measuring accuracy is improved.

Description

technical field [0001] The invention relates to an ultrasonic sensor, in particular to an ultrasonic sensor for a flow meter. Background technique [0002] As we all know, an ultrasonic flowmeter is a device for measuring the flow of fluids such as gas and liquid, and an ultrasonic sensor is one of the key components of an ultrasonic flowmeter. When the time difference method is used to measure the fluid flow velocity, the working principle is to install an ultrasonic sensor on the downstream and downstream of the fluid flow path with a specified cross-sectional area. One of the upstream and downstream ultrasonic sensors emits ultrasonic waves and the other receives ultrasonic waves. They work alternately. During transmission, its propagation velocity is superimposed on the fluid velocity, so there is a time difference in the propagation time of forward and reverse ultrasonic waves, based on which the fluid velocity can be calculated, and then the flow value can be obtained....

AI Technical Summary

Problems solved by technology

[0005] (1) The function of the ultrasonic sensor is to convert mechanical energy into electrical energy, that is to say, to convert the ultrasonic signal in the form of a pulse into an electrical pulse signal. The received energy is not concentrated enough, mainly because there is a difference in the strength of the received signal between the central part and the surrounding part. Therefore, the sensor has non-uniformity of received signal strength, which will reduce the signal-to-noise ratio of the received signal;

[0006] (2) Although there is non-uniformity in the forward and reverse directions, the non-uniformity in the forward and reverse directions is inconsistent, which results in the asymmetry of the received signal strength of the two sensors, which directly affects the signal generation circuit and signal reception. The effect of the circuit processing the signal

[0008] The disadvantage of the ultrasonic sensor used in the flowmeter above is that the strength of the ultrasonic signal received by the ultrasonic sensor on the receiving side is not uniform. The signal received by the ultrasonic sensor is asymmetrical

Unevenness will lead to a decrease in the signal-to-noise ratio, and asymmetry will increase the burden on the signal processing circuit, both of which directly affect the accuracy of flow measurement

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