SU957021A2 - Device for measuring pressure - Google Patents

Description

(54) DEVICE FOR MEASURING PRESSURE

one

The invention relates to a reference measurement technique, in particular to devices for measuring pressure.

According to the main author. St. No. 901864, pressure measuring devices are known, comprising a piezoelectric element with conductive electrically isolated surfaces, a differential signal processing circuit, an excitation generator, and an indicator, one of the conductive surfaces of the piezoelectric element being divided into three electrically isolated sections, and a central portion connected to the excitation generator, peripheral areas - to the differential scheme 1.

The disadvantages of these devices are a decrease in the measurement accuracy when the medium under test is fed from both sides of the piezoelectric element.

The purpose of the invention is to increase the accuracy of measurements.

The goal is achieved by the fact that the other conducting surface of the piezoelectric element is made in the form of coaxial disk and ring electrodes, the peripheral sections are connected in parallel and connected to one of the differential inputs.

circuit, the other input of which is connected to the ring electrode, and the disk electrode is connected to the input of the airing generator.

The drawing shows a diagram of the device.

The device contains a piezoelectric element 1, on one of the sides of which are located driving, electrically insulated from each other surfaces in the form of a central portion of electrode 2 and peripheral

10 sections of the electrodes 3. The peripheral sections are connected in parallel directly in the plane of the piezoelectric element and form an annular electrode. On the other side of the piezoelectric element 1 are placed coaxial disk 4 and

15 ring 5 electrodes. The electrodes 2 and 4 are connected to the inputs of the excitation generator 6. The ring electrodes 3 and 5 are connected to the inputs of the differential signal processing circuit 7, the output of which indicator 8.

The device works as follows.

When the generator 7 is operating, the piezoelectric element is excited at a certain mechanical frequency by the action of electrical signals. The mechanical vibrations of the central part of the piezoelectric element are transmitted to its peripheral part. In this case, electric charges are generated on the ring electrodes 3 and 5. The magnitude of the amplitude of the electric signal generated depends on the pressure applied to the surface of the piezoelectric element. With equal pressures on both sides of the piezoelectric element, the electrical signals at electrodes 3 and 5 are equal and there is no signal at the output of the differential circuit. At different pressures on the sides of the piezoelectric element, the equilibrium of the differential circuit is disturbed and a signal appears at its output, which is recorded by the indicator 8.

The device makes it possible to increase the accuracy of measuring the pressure of the test medium when it is supplied from both sides of the piezoelectric element. The symmetrical design of the piezoelectric element provides the same sensitivity.

when registering the pressure difference of a different sign.

Claims (1)

Invention Formula Device for measuring the pressure on the author. St. No. 901864, characterized in that, in order to increase accuracy, the other conducting surface of the piezoelectric element is designed as coaxial disk and ring electrodes, the peripheral sections are connected in parallel and connected to one of the inputs of the differential circuit, the other input is connected to the ring electrode, and the disk one the electrode is connected to the input of the excitation generator. Sources of information taken into account in the examination 1. USSR author's certificate in application No. 901864, cl. G 01 L 9/08, 1977.