RU2247954C2 - Transducer responding to mechanical quantities - Google Patents

Abstract

FIELD: measuring engineering.

SUBSTANCE: transducer has sensor set in pressure-tight housing and connected with control device which is in communication through the adjusting member with the "mechanical quantity-displacement" transducer made of bellows. The control device is made of a microswitch. The sensor is made of a resonator. The adjusting member is made of a rod made of ferromagnetic or diamagnetic material.

EFFECT: enhanced reliability.

3 cl, 7 dwg

Description

The invention relates to measuring equipment, is intended for measuring mechanical quantities - pressure, deformation, displacements, and can be used in automation tools for controlling technological processes of complex technical systems of a fuel and energy complex, nuclear power plants, automobile and railway vehicles, and other industries.

There are a large number of physical sensors that are diverse in design: mechanical (pressure, displacement, impact); temperature chemical (humidity, gas concentration); electromagnetic (electric and magnetic fields) made using a sensitive element (SE) on surface acoustic waves (SAWs) [1].

There is a strain-sensitive sensor on surface acoustic waves (SAWs) [2], which contains a piezoelectric sound guide in which the measured force is read by moving an elastic element that changes the propagation time of the SAW in sound ducts from interdigital transducers to read electrodes.

The disadvantage of all known design and circuit solutions of sensors using SAW devices as a CE is the need to supply electrical displacements to the SAW device and the organization of communication lines with reference SAW devices of a similar purpose and electronic circuits removed from the field of physical quantities to isolate the difference signal between test and reference SAW devices, the so-called communication devices with the object (USO).

Closest to the claimed device is a pressure sensor [3], which contains a housing with a fitting, a membrane located in a chamber connected to the fitting in the housing, a delay line on surface acoustic waves (SAW) with input and output interdigital transducers, and an electronic circuit, which includes SAW self-oscillators, each of which is formed by the inclusion of an amplifier between the input and output interdigital converters of each delay line, a frequency subtraction unit, and after the membrane, on the other a fixed plate is installed on the side of the fitting, on each side of which a delay line is formed, on the side of the membrane facing the side of the fixed plate with one of the delay lines in the region of the delay line, a metallized section is made with a length of no more than the acoustic length of the delay line, the distance between each other facing to a friend, the delay line on the fixed part and the metallized area on the membrane is not more than a quarter of the surfactant wavelength, and shapers are introduced into the electronic circuit of the sensor mpulsov, each of which is connected to the output of the corresponding SAW oscillator, and output - with one of the inputs of the frequency subtracter,

The disadvantage of this device is the need to supply voltage to ensure the functioning of electronic circuits in the sensor. Also, the housing of the pressure sensor itself is not sealed, and the presence of moisture, oil, and contaminants on the surface of the delay lines on the surfactant reduces its reliability.

The technical result of the claimed device is to ensure non-volatile operation of the sensor of mechanical quantities, as well as the exclusion of direct measured mechanical effects and environmental influences on the surface of devices on surface acoustic waves.

The technical result is achieved by the fact that in a mechanical quantity sensor, a device based on surface acoustic waves is made in the form of a resonator with input and output interdigital transducers, which is enclosed in a sealed housing with a drained controlled medium, and the input and output interdigital transducers are connected to control body, made in the form of a microswitch, connected through a regulating element with a transducer “mechanical value - movement” in the form of fona.

In a mechanical quantity sensor, a device based on surface acoustic waves is made in the form of a delay line on surface acoustic waves with an input and several output interdigital transducers, is enclosed in a sealed enclosure with a drained controlled medium, and through output terminals each output interdigital transducer is connected to a governing body, made in the form of several microswitches connected through a regulating element with a converter “mechanical value - moved e "in the form of bellows. The number of output interdigital converters and the corresponding number of microswitches is equal to the number of measured values.

In a mechanical quantity sensor, a device based on surface acoustic waves is made in the form of a delay line on surface acoustic waves with input and output interdigital transducers, is enclosed in a sealed enclosure with a drained controlled medium, and the output transducer is connected to a control body made in the form of an inductance coil through pressure outputs , in which a regulating element is installed in the form of a rod of ferromagnetic or diamagnetic material, connected to the “mechanical the physical quantity is displacement ”in the form of a bellows.

Figure 1 schematically shows a sensor of mechanical quantities; figure 2 shows the pressure switch; figure 3 shows the dependence of the change in the amplitude of the measured delayed signal from the controlling mechanical effect; figure 4 - multi-level pressure switch; figure 5 - dependence of the amplitude change of the measured delayed signals from the controlling mechanical effect - pressure; figure 6 - pressure sensor; Fig.7 - the dependence of the amplitude change of the measured delayed signal from the controlling mechanical effect.

The transducer 1 "mechanical quantity - displacement" is made in the form of a bellows and through the regulating element 2, which sets the threshold for the sensor, is connected to the governing body 3. The device on the surface acoustic waves 4 is connected through the pressure outputs to the governing body 3. The SAW device is sealed case with a drained controlled environment, consisting of a mixture of gases - argon 95% and helium 5%, or nitrogen 95% and helium 5%.

The proposed sensors work as follows.

The pressure switch (figure 2).

When a mechanical quantity P is affected by a mechanical quantity-displacement transducer 1, its displacement is proportional to the applied force, which is converted through a control element 2 that sets the sensor threshold to mechanical control actions on the control body 3. A micro switch is used as the control body, one contact of which is connected to the input interdigital converter of the resonator, and the second contact is connected to the output interdigital converter ovatelem resonator. As a result, the contacts of the microswitch are closed, which leads to the closure of the input and output interdigital converters in the structure of the resonator. Figure 3 shows the dependence of the change in the amplitude of the measured delayed signal from the controlling mechanical effect.

Multilevel pressure switch (figure 4).

When a mechanical quantity P is affected by a mechanical quantity-displacement transducer 1, its displacement is proportional to the applied force, which is transformed through control elements 2 into mechanical control actions on the control body 3. Using the control elements 2, the sensor thresholds are set. The governing body is made in the form of several microswitches, each microswitch with one contact connected to one output interdigital converter of the delay line, and the other contact to a common bus (ground). As a result of the influence of controlling mechanical influences, the contacts of the microswitches alternately close, which leads to the switching of the output interdigital converters of the delay line to the ground. Figure 5 shows the dependence of the change in the amplitude of the measured delayed signals from the controlling mechanical effect - pressure.

Pressure sensor (Fig.6).

When a mechanical quantity P is affected by a mechanical quantity-displacement transducer 1, its displacement is proportional to the applied force, which is converted through the regulating element 2 into controlling mechanical influences on the governing body 3. The regulating element 2 is made in the form of a rod of ferromagnetic or diamagnetic material, installed in the governing body - the inductor and moved in it in the forward and reverse direction linearly under the action of the transducer "mechanical led Ichina - movement. " As a result of a change in the parameter of the governing body (inductor connected to the output interdigital converter of the delay line), the amplitude of the measured delayed signal changes. 7 shows the dependence of the change in the amplitude of the measured delayed signal from the controlling mechanical action.

The use of the present invention eliminates the direct impact of a mechanical quantity on a device on surface acoustic waves due to the fact that the effect is through articulated links (“mechanical quantity - displacement transducer”, regulating element, control element). In addition, the principle of operation of such a sensor allows you to enclose the device on the surfactant in a sealed enclosure, which eliminates the impact of the environment on the surface of the device on the surfactant.

Literature

1. Malov V.V. Piezoresonance sensors. 2nd ed. reslave. and supplemented / M.ZH ENERGOATOMIZDAT, 1989. - 271 p.

2. Ya.N. Pugachev. Strain-sensitive sensor on surface acoustic waves (SAW) / USSR State Committee for Inventions and Discoveries: Patent SU No. 1159153, IPC N 03 N 9/00, G 01 L 9/08, publ. BI No. 20, 1985

3. RU 2036446 C1 (Bazhenov V.I.), 05.27.1996. Pressure sensor (prototype).

Claims (3)

1. A mechanical quantity sensor comprising a device for surface acoustic waves, characterized in that the device for surface acoustic waves, made in the form of a resonator with input and output interdigital transducers, is enclosed in a sealed enclosure with a dried controlled medium and through input and output hermetic outputs the interdigital transducer is connected to the governing body, made in the form of a microswitch connected through a regulating element to the transducer "mechanical elichina-moving "in the form of bellows. 2. A mechanical quantity sensor comprising a device for surface acoustic waves, characterized in that the device for surface acoustic waves, made in the form of a delay line for surface acoustic waves with input and output interdigital transducers, is enclosed in a sealed enclosure with a dried controlled environment and connected via a pressure seal to a control body made of several microswitches connected through a control element with a mechanical shift-motion "in the form of a bellows, while as a result of alternately closing the contacts of the microswitches, the output interdigital converters of the delay line are switched to ground. 3. A mechanical quantity sensor comprising a device for surface acoustic waves, characterized in that the device for surface acoustic waves, made in the form of a delay line for surface acoustic waves with input and output interdigital transducers, is enclosed in a sealed enclosure with a dried controlled environment and through the hermetic outputs, the output interdigital converter is connected to a control body made in the form of an inductor in which a control element is installed nt in the form of a rod of ferromagnetic or diamagnetic material associated with the converter "mechanical-displacement value" in the form of bellows.

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