SU945683A1 - Ultrasonic device for measuring temperature - Google Patents

Description

one

The invention relates to ultrasonic temperature measuring devices and can be used to measure temperature micropulsations in media.

A device for measuring temperature with ultrasound is known, in which a change in the temperature of the working medium leads to a phase shift of the ultrasonic wave received by tg by two piezo transducers spaced apart by a certain distance 1.

The disadvantages of this device are low sensitivity and a large norpeojHOCTb measurement of rapidly changing 1x temperatures.

The closest to the proposed technical essence and the achieved result is an ultrasonic device. For temperature measurement, containing an electromagnetic oscillator with acoustic feedback, a resonator and a display unit 2.

A disadvantage of the known device is the low accuracy of temperature micropulsation measurement.

The purpose of the invention is to increase the accuracy of measuring rapidly varying temperatures.

Claims (2)

The goal is achieved by additionally introducing a second generator with acoustic feedback into the device, a mixer whose inputs are connected to the outputs of the generators, and its output is connected to one of the inputs of the display unit, the second input of which is connected to the output of the second generator, and the resonator identical to the first one and placed with it in the same housing; moreover, holes are made in the walls of the resonators, the areas of which differ from each other by no less than two orders of magnitude, and the thermal constants of the resonators are equal. 39 The drawing shows the proposed device. The device contains a detachable housing 1, ultrasound transducers 2-5 rigidly fixed in it, resonant chambers 6 and 7 with holes 8 and 9 separated, in order to prevent their mutual influence, with a damping medium 10, generators 11 and 12 which are amplifiers , mixer 13, block AND display, plugs 15 and 16 The device operates as follows. The housing 1 of the device is placed in an environment whose temperature is measured. Through holes 8 and 9, the resonant chambers 6 and 7 are filled with a medium (liquid) serving as the sound duct of the resonators, one of which is formed by ultrasonic transducers 2 and 3 and a resonant chamber 7, the other by ultrasonic transducers A and 5 and a resonant chamber 6. When electrical current is applied to the electronic part of the device, consisting of amplifiers 11 and 12, a mixer 13, the inputs of which are connected to the outputs of the generators, and its output is connected to one of the outputs of the display unit k of the second generator pa, resonance chambers are formed in upstanding akustiche.skie wave whose frequency is determined by the distance between the transducers 2, 3 and 4, 5 temperature liquid present in peso-, cy- chambers 6 and 7 as well as temperature transducers themselves. By choosing a certain ratio of the areas of the holes 8 and 9, the frequency of the generator 11 is determined by both fast and slow changes in the temperature of the controlled medium, and the frequency of the generator 12 is determined only by slow changes in the temperature of the medium. The signals from the outputs of the GENOTOPOB 11 and 12 are fed to the mixer 13, in which the separation of the difference frequency occurs, which is then converted to the temperature in the AND AND Indication unit. The difference frequency from the mixer 13 is proportional to the rapid changes in the temperature of the controlled medium, because, due to the equality of thermal resonators and their identity, the error due to changes in the temperature of the transducers themselves, the size of the resonant chambers and the slow changes in the temperature of the liquid, minimized. The invention makes it possible with high accuracy (the error does not exceed 1) to measure rapidly varying temperatures of a liquid medium. The measurement threshold sensitivity is ten decimal fractions of a degree. For reliable operation of the device, the distance between the transducers is selected within 0.5-1.5 lengths of the standing acoustic wave, which makes it possible to measure temperature micropulsations in a very small volume. Ultrasonic device for measuring temperature, containing an electromagnetic oscillator with acoustic connection, resonator and display unit, characterized by the fact that, in order to improve the accuracy of measurement of fast transient temperatures, a second generator with acoustic feedback is additionally introduced into it, the mixer, the inputs of which are connected to the outputs of the generators, and its output is one of the inputs of the display unit, the second input of which is connected to the output of the second generator, and the resonator is identical first and razmacenny with him in the same housing, and in the walls of the resonators there are holes, the areas of which differ from each other by no less than two orders of magnitude, and the thermal constants of the resonators are chosen equal. Sources of information taken into account in the examination 1. UK Patent No. 10736, cl. H D, 1967. 2. USSR author's certificate number 119700, cl. G 01 K 11/26, 1958.