SU596834A1 - Sound pressure measuring device - Google Patents

Description

FIG. 1; the scheme of the proposed device has been identified; Fig 2 - yae compensation.

The device contains a generator 1 connected to the electrode 2 of the compensating converter 3 at points 4. and 5, and a measuring device (indicator zero) b connected to the electrical output of the turn-electrode 7 at points 8, 9, 5. At the ends of the converter are sealing and shock-absorbing pads 10, permanent magnets 11, having the form of cylinders. A sensing element (a multi-turn current-conducting winding) 12, rigidly connected with this electrode, is placed over the outer electrode 7.

In the simplest case, the sensing element (conductive winding) is formed by an outer coil electrode 7 with terminals 8, 9 and is a midpoint of 5 Tok 4 and 5 on electrodes 2 and 7 are electrical pins of the compensation converter. Electrodes to prevent electrical closure of the coil are cut along the generatrix along the axis of the cylinder (the gap of the electrodes is shown in section AA between points 8 and 9). Winding 12 increases the sensitivity of the electrodynamic converter.

The device works as follows. . .

The working medium of the converter 3 placed into the working environment sounded by the measured sound pressure is excited from the generator 1, the phase and the amplitude of the generator are changed to receive the zero signal of the zero indicator, which corresponds to the moment of compensation of external forces caused by the measured sound pressure on the working surface Transducer internal piezoelectric. The magnitude of the measured voltage. excitation converter. (compensation voltage) judge the sound pressure level in the working environment.

Device self-grading can be performed as follows.

The compensation unit will be placed into the working environment where a certain value of sound pressure is maintained and the voltage generated by this pressure is measured and at the output of the compensation device. Then the compensation converter is excited by the compensation voltage U and - measure the value of the latter at the moment of compensation (E-0). After that, switching off the sound pressure source and not changing the excitation mode of the compensating converter, the current 3 of its excitation and the emf E at the winding output are measured.

The compensation constant M c is calculated by the formula

M - and 3

in th, T

B is a component of the induction of the magnetic field, parallel to the axis of the winding; E is the length of the winding; SP is the radiation area -, time dependence-: B can be made very insignificant if permanent magnets are used as a node creating a magnetic field, for example, from an UNDK-24 alloy changing induction by no more than 2% . for 30 years.

The main advantage of the device is the absence of a fundamental error in the measurement of sound pressure associated with the final thickness of the compensation transducer, which prevents restrictions on use when. high hydrostatic pressures and the possibility of simple self-calibration in the operating position.

Claims (1)

Invention Formula An apparatus for measuring sound pressure by the piezoelectric compensation method, comprising a generator connected in series ,. compensatory transducer, (acusgically rigidly connected along the working surface with a sensitive element; meter, measuring device, which is so that, in order to increase the measurement accuracy and ensure self-calibration of devices, the compensating converter is equipped with constant magnets, installed with opposite polarity through sealing-gaskets-; p. 6. 6rp butt-ends, and the sensing element -.produced from the current, winding, coaxially with the compensating converter. Sources of information taken into account, with. examination; 1, Klyukin. II, Kolesnikov A.E., Acoustic measurements in shipbuilding, L., Shipbuilding, 1968, pp. B1-6.2. 2, Copyright certificate № 188865 cl. G. 01 H 3/12, 1965, .i