SU1326917A1 - Piezoresonance pressure transducer - Google Patents

Abstract

The invention relates to instrumentation engineering and reduces the multiplicative component of the temperature error and eliminates false signals under the action of vibration and shock loads. The effective force through the cantilever beam 2 and the rod 3 with elastic hinges is transmitted to the end of the arm-yoke 4 with the balancing weight 6 at the end. The deformation of two identical piezoresonators 8 causes a change in their frequencies. The differential principle of switching on piezoresonators 8 excludes the change in frequency at the output of the sensor during temperature distortion. Bilateral notches on the power transfer rod 3 contribute to increasing the sensitivity of the pressure sensor. 3 il. .C & (L O9 s O); 0 "FI.1

Description

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The invention relates to instrumentation engineering, in particular, to pressure sensors for measuring absolute pressure.

The purpose of the invention is to reduce the multiplicative component of the technical error and eliminate spurious signals under the action of vibration and shock loads.

Figure 1 shows a piezo-sensor circuit with a compensator; figure 2 - piezoresonance sensor, General view, in section; Fig. 3 is a block diagram of pressure measurement.

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The piezoresonance pressure sensor comprises a housing 1 with a power-receiving beam 2 attached to it, at one end of which a force F acts. The second end of the beam is elastically attached to the housing 1 through a hinge formed by double-sided cuts made in the body of the beam. The effective force F, increased in proportion to the beam arms, is transmitted to the transmitting bar 3, connected by its central part with the end of the rocker arm 4 attached to the support 5. At the second, free end of the rocker arm a shiftable balancing weight 6 is attached. Piezo elements 7 and 8, on its side, are coaxially attached on both sides to the lever-beam 4 between the support and the attachment point of the force-transmitting rod 3, which is fastened with its second end to the compensation beam 9. The transmitting beam 2 and the beam 9 (Fig.2) are fastened the casing with screws 10 and 11. The beams 2 and 9 with the rods 3 are also fixed with screws 12 and 13. The rod 3 with the end of the rocker arm is connected through the collar 14. The piezoelectric elements 7 and 8 are fastened to their ends with their faces frame 15, fixed in the housing, and with a lever-beam. The lever-beam 4 rests on two-sidedly cut out support legs 16. At the second end of the lever-rocker arm 4, a balance weight 6 is fixed, the position of which on the lever-rocker arm is established experimentally and fixed. A corrugated membrane 17 is fastened on the upper part of the corpus of the case, and a fitting 18 is soldered on top of it. The rigid center of the corrugated membrane 17 is fastened to the projection 19 of the advance ball 2.

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The block diagram for measuring the absolute pressure (Fig. 3) contains elements 7 and 8, which are included in the circuit of the autogenerators 20 and 21. To increase the sensitivity, the block diagram includes frequency multipliers 22 and 23, the output signals of which are at frequencies f and f to the mixer 24. At the output of the mixer signal has a frequency f ..

The piezoresonance pressure sensor operates as follows.

The effective force through the beam 2 and the rod 3 is transmitted to the end of the rocker arm 4. Piezoelectric element 7 expands and increases its frequency by + 4f, and piezoelectric element 8 contracts and decreases its frequency by - df.

After multipliers 22 and 23, the frequency of the oscillators will be equal to n (fg + uf) and n p () (it was assumed that the frequencies of the oscillators are equal to fo), the multiplication factor. After mixing 24, the output frequency will be nj2df. In order to measure both pressure and vacuum, the initial frequencies of the oscillators should be slightly different from each other.

In the proposed sensor (compared to the known one), due to the additional compensating beam, the multiplicative component of temperature error is significantly reduced, and due to the differential principle of switching on piezoelectric elements, the temperature distortion of the balance arm rocker does not create a frequency change at the output.

A force balancing system in the form of a balance arm with a weight increases the resistance of the system to vibration and shock loads. Bilateral leads on rod 3 increase sensitivity.

Claims (1)

Invention Formula A piezoresonance pressure sensor, comprising a housing, which is cantilever-mounted through an elastic hinge with a force-bearing beam, the end of which is connected to the sensitive element and the first piezoresonator in the form of a plate, which is characterized by the fact that, in order to reduce the multiplicative component of the temperature error and elimination false signals at action vibration and shock sensor is provided mounted on a support a two-armed lever-rocker arm with a balancing weight at the end, siloperedayuschim rod with two elastic hinges vsholnenn1mi on both sides of its ends attached to the housing and provided with a resilient hinge compensation beam and the second piezo resonator, identich269174 At the first end, the siproise transmitting rod is connected with a force-transmitting beam at one end, and with a compensation beam at the second end, and with its middle part attached to the end of the rocker arm, and the piezoresonators are coaxially connected to the body and to the lever shoulder. rocker, and placed on both sides between ten support and power-transmitting rod .. 12 Fzg.2 Yy jt go .J 21 Editor A.Revin Compiled by S. Romansky Tehred A. Kravchuk Proofreader. Shekmar Order 3272/36 Edition 776 Subscription VNIIPI USSR State Committee for inventions and discoveries 113035, Moscow, Zh-35, Raushsk nab., 4/5 Production and printing company, Uzhgorod, Projecto st., 4 22 / g 2 f-fr-fi 23 2 Fig.z.