SU1290113A1 - Compensating pneumoelectric pressure meter - Google Patents

Abstract

The invention relates to a measurement technique and makes it possible to increase the sensitivity of a pressure meter. In the absence of input pressure, the measuring bridge 5 is balanced. When pressure appears, the level of the liquid dielectric 3 between the electrodes 1 and 2 is shifted, which leads to a change in the capacitance at the output of the capacitive transducer. The error voltage from the output of the measuring bridge 5, proportional to the change in capacitance, is fed to the input of the non-compensating amplifier 6, from its output, the amplified non-compensating signal is fed to the input of the amplifier 7 and is powered by a power indicator 8 and pressure. Power amplifier 7 produces a high voltage, the amplitude of which is proportional to the non-compensation signal. 1 il. ig (L to x

Description

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The invention relates to measuring technology and is intended for use in pneumatic and hydraulic automatic devices. The aim of the invention is to increase the sensitivity of the meter. ,

The drawing shows a schematic diagram of a compensating pneumoelectric pressure gauge,

The meter comprises an internal electrode 1 of a primary coaxial capacitive pressure transducer, an external electrode 2, a liquid dielectric 3, a housing 4, an ac measuring bridge 5, a non-compensation amplifier 6, a power amplifier 7, and a pressure indicator 8.

The meter works as follows.

If there is no input pressure P in bridge 5, it is balanced. When a pressure inlet appears, the level of the liquid dielectric 3. 25 is displaced between electrodes 1 and 2, which leads to a change in capacitance C at the output of the primary capacitive converter. The error voltage from the output of bridge 5, proportional to the change in Q capacitance, enters the input of amplifier 6 uncompensation, from its output a reinforced uncompensation signal is applied to the input of power amplifier 7 and to pressure indicator 8. The power amplifier produces a high voltage, the amplitude of which is proportional to the non-compensation signal.

The output voltage of the power amplifier is applied between the electric Q house 2 of the primary capacitive transducer. pressure housings and housing 4, which

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Compiled by V.I1estak Editor A.Lezhnina Tehred A.Kravchuk Proofreader S.Cherni

Order 7890/36 Circulation 799 Subscription VNIIPI USSR State Committee

for inventions and discoveries 113035, Moscow,, Raushsk nab., d, 4/5

Production and printing company, Uzhgorod, Proektna St., 4

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made of metal. Under the action of ponderomotive forces arising in an electric field, a quasi-static displacement of the dielectric fluid occurs in the direction opposite to the direction of displacement of the liquid level under the influence of the input pressure, which leads to a reverse change in capacitance C. and balancing the measuring bridge 5. The magnitude of the non-compensating signal is in this case proportional to the magnitude of the input pressure P. and is recorded on the pressure indicator 8. Thus, in the proposed meter, the transmission coefficient is increased due to the absence of a special inverter in the feedback circuit, which ensures the sensitivity of the meter.

Claims (1)

Invention Formula Compensation pneumoelectric pressure gauge containing a primary capacitive transducer, made in the form of two coaxial electrodes installed in a housing,. filled with a dielectric fluid, and connected to an AC measuring bridge, the measuring diagonal of which is connected to the input of the non-compensation amplifier, the output of which is connected to a power amplifier and pressure indicator, characterized in that, in order to increase the sensitivity, the body of the primary capacitive converter is made of metal, and the output of the power amplifier is electrically connected to the body of the capacitive converter and its external electrode.