SU1281523A1 - Device for measuring pressure - Google Patents

Abstract

The invention relates to instrumentation engineering and makes it possible to reduce the measurement error at high temperatures. With one f :. f f L -.v. the sides of the dielectric substrate 3 mounted on the membrane 2 are placed on a common core 9 electrodes cathodes 5 and 6 of the measuring 7 and auxiliary 8 diodes. When a pressure is applied to the membrane 2, the current of the measuring diode 7, recorded by the measuring device 13, changes from graduated in units of pressure. When the ambient temperature fluctuates, the current of the auxiliary diode 8 changes. The signal from the anode 11 of the diode 8 through the stabilization system 15 controls the power of the preheater 4, ensuring the stabilization of the current of both diodes. Placing the anodes 10 and 11 on the dielectric substrate 12 mounted on the housing 1 allows for reduced-.-: leakage currents occurring at high temperatures relative to the measured currents. 1 il. U) J - «/ / / ZhSh ShShShShShSh - - / / / / Shshshsh th 00 SP N9 WITH

Description

(21) 382D921 / 24-10

(22) 11.12.84

, (46) 07.01.87. Bksh. № 1

(71) Moscow Aviation Technological Institute. K. E. Tsiolkovsky

(72) C. N. Chernov, A. M. Vasiliev, V. G. Blokhin, V. A. Seleznev,

A.V. Martynov, M.N. Levin,

B.P. Efimov and I.P. Kvasnevsky (53) 531.787 (088.8)

(56) USSR Author's Certificate No. 575513, class; G 01 L 9/00, 1976,

USSR author's certificate number 872990, cl. G 01 L 9/00, 1981. (54) DEVICE FOR MEASURING THE PRESSURE

(57) The invention relates to instrumentation engineering and reduces the measurement error at high temperatures. From one

the sides of the dielectric substrate 3 mounted on the membrane 2 are placed on a common core 9 electrodes cathodes 5 and 6 of the measuring 7 and auxiliary 8 diodes. When a pressure is applied to the membrane 2, the current of the measuring diode 7, recorded by the measuring device 13, changes from graduated in units of pressure. When the ambient temperature fluctuates, the current of the auxiliary diode 8 changes. The signal from the anode 11 of the diode 8 through the stabilization system 15 controls the power of the preheater 4, ensuring the stabilization of the current of both diodes. Placing the anodes 10 and 11 on the dielectric substrate 12 mounted on the housing 1 allows for reduced-.-: leakage currents occurring at high temperatures relative to the measured currents. 1 il.

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The invention relates to instrumentation engineering and can be used to measure pressure in the high temperature region.

The purpose of the invention is to reduce the measurement error at high temperatures.

The drawing shows a diagram of a device for measuring pressure.

The device contains an evacuated metal case Ij in which membrane 2 is pressure-sensitive. The latter has a dielectric substrate 3, on one side of which a heater 4 is placed, and on the other side electrodes (cathodes) 5 and b respectively . The cathodes 5 and 6 are placed. On a common core 9, which together with one output of the heater 4 is connected to the metal case I. The anode electrodes 10 and 11, respectively, of the measuring 7 and auxiliary 8 diodes are fixed on the dielectric substrate 1, the anode 10 of the measuring diode 7 is connected through the measuring device 13 with the plus of the source 14 of the DC power supply, minus the goTopone is connected to the housing. Temperature stabilization system 15 is connected between the anode G1 of the auxiliary diode 8 and the second output of the heating l.

The pressure measuring device operates as follows.

The measuring diode 7 is operating in the mode of limiting the current by spatial charge, when its volt-ampere characteristic obeys the law of degree 3/2. In this mode, the measuring diode 7 depends mainly on the distance between the moving cathode 5 and the anode Yu the operation mode is provided by supplying to the measuring diode 7 an appropriate voltage from the source .14 of the DC power supply.

As a result of the pressure applied to the membrane 2, it moves along with the cathode heating unit. The distance between the cathode 5 and the anode 10 of the measuring diode 7 varies, which leads to a change in the current of the measuring diode, which is recorded by the measuring device 13 (for example, a microammeter; calibrated in units of pressure.

To eliminate the error in measuring pressure caused by a change in

The emission characteristics of the cathode 5 as a result of changes in environmental parameters, such as temperature, are served by an auxiliary diode 8, which is. It works in the saturation mode of the anode current. In this mode, the current of the auxiliary diode 8 depends mainly on the temperature of its cathode b and does not depend on the distance between it and the anode 11. The saturation mode of the auxiliary diode 8 is provided by supplying an appropriate voltage to its anode supplied from the temperature stabilization system 15.

When the temperature changes surround

medium varies current supplementary

The signal from the anode 11 of the additional diode 8 is fed to the temperature stabilization system 15, which, in the form of feedback, changes the power of the pre-heater so that the auxiliary diode current is stabilized at a certain level. Since both cathodes have identical emission

characteristics and a common heater, when the current of the additional diode-a is stabilized, the current of the measuring diode is also stabilized and the influence of the ambient temperature is excluded when measuring the pressure.

Since the cathode assembly of the pressure measuring device is located on the movable membrane, and the cathodes of both diodes and one outlet of the preheater are connected to the metal case, the anodes of both diodes are much easier to isolate from the case, since it is located on it fixedly. In this case, it is possible to remove the attachment points of the anodes to the housing through the dielectric insulation from the high temperature zone of the device.

As a result, leakage currents, which occur at high temperatures, are significantly smaller in magnitude than the measured currents and do not affect the accuracy of the measurement. In addition, with this arrangement of cathodes, the number of leads is reduced to a minimum, which greatly simplifies the design of the cathode assembly and the entire device.

Claims (1)

Claims of the invention do heater and auxiliary and electrodes, different A device for measuring pressure, in order to reduce the error-containing evacuated body, the measurement properties at high temperatures, the sensor is sensitive to 5ths, the substrate is mounted on a membrane-pressure membrane, the substrate is under the substrate, and the electrodes opposing heater, two measuring and two-electrode substrate, fixed to auxiliary electrodes, -split housing, which is metal-bonded opposite each other, and one, and the dielectric diode from each pair of electro-eye is insulated from it, while the substrate electrodes Dov is located on the substrate, and is system-galvanically interconnected Mu thermostabilization, included inter-and body.