SU1765711A1 - Ultrasonic device for determining fluid level - Google Patents

Abstract

Application 1 the invention relates to a device for examining liquids. The essence of the invention. The device consists of a cup 1 containing an injector 2 connected to a circulation pump 3, and a magnetostrictive transducer 4, which are directed at an angle smaller than the second critical angle, i.e. 30 ° to the radiating plate of the ultrasonic measuring element 5, which is connected to the counting recording unit 6. 1 sludge.

Description

This invention relates to a measurement technique in the power industry, the chemical industry, and other areas of the national economy.

Predictive and evaluative studies 1 show that a ultrasonic liquid level detector 2 is known, containing piezoelectric transducers and a reading / recording unit, an ultrasonic distance meter in liquids 3 containing a reflector, a reference and measurement channels, each of which contains an electroacoustic transducer , level gauges 4.

The disadvantages of these devices are unreliability and limited application.

The closest known technical solution to the proposed is an ultrasonic level gauge 5 containing reference and measuring channels, each of which consists of a reversible electroacoustic transducer included in a synchro-ring circuit consisting of a receiving-forming unit and a probe pulse generator, as well as a time interval meter , indicator, divider and integrator.

The disadvantages of the prototype are low functional reliability and accuracy of measurements, especially in aggressive fluids, which have, as a rule, solid inclusions and air bubbles. The deposition of inclusions on the transmitter's radiating and receiving surfaces or the presence of air bubbles leads to scattering of ultrasonic vibrations and an increase in measurement error

The aim of the invention is to improve the accuracy of determining the level of liquid.

This goal is achieved by the fact that an injector connected to a circulating pump and a magnetostrictive transducer are injected in an ultrasonic device for determining the level of a liquid containing a capacitance and a reversible electroacoustic transducer connected to a recording unit.

ABOUT

ate vj

containers fastened in the holes, and their longitudinal axes are directed to the normal of the working surface of the reversible electroacoustic converter located at the bottom of the tank, under /

angle arcsin (g-), where Cu and Ct2 are the speeds of propagation of longitudinal and transverse oscillations in the fluid and solid, respectively.

The novelty of the inventive device for determining the level of a liquid lies in the combination of features that make it possible to increase the accuracy of measurements.

The essential difference of the claimed device from the prototype is that the device is equipped with a circulation pump with an injector and a magnetostrictive transducer.

The equipment of the device with an injector pump makes it possible to shoot down solid inclusions deposited on the surface of the electroacoustic transducer using a directed jet of liquid, and ultrasonic oscillations of sufficiently high power emitted by the magnetostrictive transducer make it possible to further purify this surface from air bubbles, thereby increasing the time measurement accuracy the passage of ultrasound in the liquid.

The drawing is a schematic diagram of an ultrasound device.

An ultrasonic liquid level measuring device consists of a tank 1 containing an injector 2 connected to a circulation pump 3 and a magnetostriction transducer 4 hermetically fixed in the openings of the tank, with their longitudinal axes directed to the normal of the working surface of a reversible electroacoustic transducer 5 located at the bottom of the tank, at an angle greater than the second critical angle for longitudinal vibrations in the liquid; electroacoustic transducer 5 is connected with recording unit 6.

The angle of inclination of the injector and the magnetostriction transducer (vibrator) was chosen to be less than 30 ° from the condition of complete reflection of ultrasound from the working surface of a reversible electroacoustic transducer. The power of ultrasonic vibrations of the vibrator is sufficient to destroy air bubbles on the surface of the acoustic transducer, but at angles greater than 30 ° some of the energy can

is absorbed by this surface, causing damage to it.

The value of the second critical angle is determined by the expression

Ac arcsin (§1),

(D

where Cu is the velocity of the longitudinal oscillations in the liquid (1500 m / s);

Ct2 is the transverse vibration velocity in the piezoelectric transducer of an acoustic transducer (3000 m / s).

From expression (1) we get

Acre "arcsin (3Jjjg) 30 °.

So the angle of incidence / 3 of ultrasonic vibrations on the working surface of the electro-acoustic transducer must be greater than 30 °, and the angle of inclination of the vibrator (a 90- /) is less than 60 °.

Ultrasonic device for determining the level of liquid works as follows.

In the vessel 1, filled with liquid, the working surface of the reversible electroacoustic transducer 5 emits ultrasonic vibrations, which, reflected from the surface of the liquid, are again received by the converter 5 and, converted into electrical signals, are recorded by the unit 6, which measures the passage time of ultrasound to the surface of the liquid and back.

Periodically between measurements, a pump 3 with an injector 2 creates a jet of liquid, for example, with a pressure of 3-5 atm and ultrasonic vibrations, for example, with a frequency of 5-10 kHz from the magnetostriction transducer 4, which are directed at an angle of less than 60 ° to the working surface of the electro-acoustic transducer 5 and which clean it from air bubbles and microparticles.

Technical and economic efficiency of the proposed device in comparison with the prototype, analogues and known devices is to improve the accuracy due to the removal of air bubbles and microparticles from the working surface of a reversible electroacoustic transducer using a fluid jet in the field of ultrasonic vibrations.

Claims (1)

Invention Formula An ultrasonic liquid level measuring device containing a capacitance and a reversible electroacoustic A converter connected to a recording unit, characterized in that, in order to increase accuracy, into it surface of a reversible electroacoustic converter located on Gb t I t I iwocMUj riiriTi i VTrUJVj. IrltOridwlj vjl x the injector connected to the circulator of the capacitor ™ P ° DY ™ ohm P 2kR arcsin (), the inertia pump, and the magnetostriction one are introduced, where C and Ct2 are the propagation velocities the transducer is hermetically fixed-5 longitudinal and transverse oscillations into the liquid in the capacitance holes, and their projections and in the solid, respectively, the longitudinal axes are directed to the normal surface of a reversible electroacoustic converter located on Gb lj vjl x bottom of capacitance ™ P ° DY ™ ohm P 2kR arcsin (), where C and Ct2 are the propagation speeds