Built-in tuning fork type vibration plate sensor

Abstract

A built-in tuning fork type vibrating plate sensor belongs to the field of measuring instruments and comprises a base, a steel tube probe and a detection portion composed of a vibrating plate and a built-in tuning fork, the tuning fork is arranged on the vibrating plate in the steel tube probe, the vibrating plate is connected with the front end of the steel tube probe, and ceramic piezoelectric elements are arranged on the tuning fork and the vibrating plate in the steel tube probe. Only the vibration plate at the front end of the steel tube probe participates in detection, and the sensor has higher impact resistance and stable resonant frequency.

Description

Technical Field

[0001] The utility model belongs to the field of measuring instruments, and particularly relates to a built-in tuning fork type vibration plate sensor. Background Art

[0002] When measuring the level height of liquid substances and powder materials, it is often necessary to accurately measure its level height. In the prior art, the sensor probe can be used to generate vibration for measurement. When the probe touches the measured object, its vibration amplitude decreases sharply. The piezoelectric element in the sensor converts this amplitude change into an electrical signal output value change to realize the level measurement and control program.

[0003] Currently, there are two types of sensors of this type sold on the market: tuning fork vibration type and single rod vibration type. The tuning fork vibration sensor is a symmetrical vibration unit sensor, and the single rod vibration sensor is an asymmetrical vibration unit sensor. Both sensors have poor impact resistance, short service life, and large size. They are both complex sensors with tuning forks as probes. Therefore, it is necessary to design a new type of plate vibration sensor that can be used in small spaces for more accurate measurement, is more compact, has high impact resistance, and has a long service life. Summary of the invention

[0004] The purpose of the utility model is to overcome the defects of the existing symmetrical tuning fork vibration sensors and asymmetrical rod vibration sensors, such as large volume, poor impact resistance, complex structure and short service life, and to design a new vibration sensor with a built-in tuning fork vibration plate, which is small in size, good in strength and impact resistance. The utility model is realized by the following technical scheme: a built-in tuning fork vibration plate sensor, including a vibration plate 1, a steel pipe probe 2, a built-in tuning fork 3, a base 4 and a ceramic piezoelectric element 5, characterized in that the vibration plate 1 is connected to the front end of the steel pipe probe 2, and the built-in tuning fork 3 is welded to the pipe The inner vibration plate 1 can also be welded on two vibration plates respectively to form a tuning fork. The two ceramic piezoelectric elements 5 installed in the tube are pasted on the lower end of the outer side of one tuning fork 3 and the lower vibration plate of the outer side of the other tuning fork 3. The ceramic piezoelectric element on the vibration plate is connected to the excitation signal output end of the oscillation circuit, and the ceramic piezoelectric element on the tuning fork is connected to the signal feedback input end of the oscillation circuit. The base 4 is connected to form a plate vibration sensor with a built-in tuning fork in which the vibration plate 1 at the front end of the steel pipe probe is the detection element. The minimum diameter and length of the probe steel pipe are determined by the minimum size of the ceramic piezoelectric element and the minimum length of the built-in tuning fork.

[0005] This sensor can be made into probes with different diameters of 5+mm and lengths of 10+mm according to different usage scenarios. The vibration frequency of the probe vibrator is also determined by the resonance frequency of the built-in tuning fork and the thickness of the steel plate. The tuning fork can be designed to have a resonance frequency range of 30~1000HZ.

[0006] In this sensor, the ceramic piezoelectric element is placed on the vibration plate and tuning fork inside the steel pipe probe, and is not affected by the impact of the probe steel pipe. This overcomes the defects of tuning fork and vibrating rod sensor probes that cannot withstand large impacts, the probe cannot be miniaturized, and the manufacturing process is complicated.

[0007] The positive benefit of this solution is that after the tuning fork is built in, it overcomes the defect of similar vibration sensors that the detected object directly impacts the probe and causes damage to the ceramic piezoelectric element. The built-in very small tuning fork resonates, drives the detection plate to vibrate, and realizes the control signal conversion, so it can be made into a built-in tuning fork vibration plate sensor.

[0008] The following further describes the embodiments in conjunction with the accompanying drawings: BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 This is the appearance diagram of the built-in tuning fork vibration plate sensor;

[0010] Figure 2 A cross-sectional view of the built-in tuning fork vibration plate sensor. DETAILED DESCRIPTION

[0011] In the figure, the diameter of the vibration plate 1 is determined according to the inner diameter of the steel pipe probe 2: 3~500mm, the thickness of the steel plate is determined according to the vibration frequency and strength requirements: 0.1~5mm, the outer diameter and length of the steel pipe probe 2 can be determined according to the use and installation design, the built-in tuning fork 3 is a rectangular steel plate, corresponding to the size and resonance frequency of the vibration plate 1, the length l, width s and thickness t of the design plate are determined, the vibration plate 1 is welded to the bottom end of the steel pipe probe 2, the built-in tuning fork 3 is symmetrically spaced 0.5mm+ and welded to the upper position of the vibration plate in the tube, the middle or edge of the plate is also acceptable, and the ceramic piezoelectric element 5 is pasted on the lower part and On the steel plate below the side of the opposing tuning fork, after wiring, the vibration plate 1 and the tuning fork are installed in the steel pipe probe. After welding, the other end of the steel pipe probe is welded to the base 4. The ceramic piezoelectric element on the vibration plate is connected to the excitation signal output end of the oscillation circuit, and the ceramic piezoelectric element on the tuning fork is connected to the signal feedback input end of the oscillation circuit. During detection, the control board is energized, and the weak vibration signal of the ceramic piezoelectric element of the vibration plate is fed back to the ceramic piezoelectric element of the tuning fork through the oscillation circuit. The tuning fork generates continuous resonant vibration, driving the vibration plate to vibrate continuously. When the vibration plate contacts the material, the material is damped, the tuning fork stops vibrating, and the output switch signal.

Claims

1. A built-in tuning fork type vibration plate sensor, comprising a vibration plate (1), a steel pipe probe (2), a built-in tuning fork (3) and a probe part consisting of a base (4), characterized in that: The vibration plate (1) is connected to one end of the steel pipe probe (2), and the built-in tuning fork (3) is rigidly placed on the upper end of the vibration plate (1) inside the steel pipe and is built into the steel pipe probe (2). The two ceramic piezoelectric elements installed therein are placed on one side of the tuning fork (3) and on the vibration plate (1) at the lower end of the other side of the tuning fork (3).

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