SU1529056A1 - Device for measuring temperature of metal objects in vacuum - Google Patents

Abstract

This invention relates to instrumentation technology. The purpose of the invention is to improve the measurement accuracy. The introduction of an additional measuring electrode 5 and model element 6 allows comparing the currents of thermionic emission of the sample element 6 and the moving lengthy metal object (TO) 7, which allows with the equality of the currents of thermionic emission of the sample element 6 and TO 7 to determine the temperature TO 7 by the temperature of the sample element 6 using a thermocouple and thereby improve the measurement accuracy. 2 Il.

Description

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The invention relates to instrumentation technology and can be used to measure the temperature and travel of moving long metal objects in the metal processing, electronic, instrument making industry.

The aim of the invention is to improve the measurement accuracy.

1 shows a block diagram of the device; Fig. 2 shows an example of the construction of the measuring electrode. The device includes a four-shouldered measuring bridge containing two parallel branches, one of which is formed by series-connected resistor 1, measuring electrode 2 (Fig 2) and contacting device 3, the second is sequentially switched on by resistor 4, an additional measuring electrode 5 and an exemplary element 6. The object of measurement 7 is a moving wire. Exemplary element 5 is made of the same wire. The measuring electrodes 2 and 5 are made in the form of hollow cylinders. A source of a constant voltage 8 is connected to common points of the branches A and B, which provides a constant voltage, the negative pole of the source and the point B are connected to the point A and positive. A DC amplifier 9 is connected to the measuring diagonal of the LED bridge 9. The amplifier output is connected to the input of a controlled current source 10, the input of which is connected to the ends of the sample element 6. The junction of the thermocouple 11 connected to the input of the TCM meter is mechanically connected to the sample element.

Exemplary element 6, measurement object 7, measuring electrodes 2 and 5, and thermocouple 11 are placed in a vacuum chamber 13.

The device works as follows.

The measurement object 7 is connected via the contact device 3 to the negative pole of the DC voltage source 8. The measurement object 7 heats up, the density of the current of thermionic emission increases, which causes imbalance of the bridge. The unbalance signal of the bridge, amplified by amplifier 9, is fed to the input of a controlled current source 10, which increases the current passing through the

raztsovy element 6 "At the same time it is raised. The temperature of the reference element 6 shrinks and, accordingly, the current density of thermionic emission increases until the density of currents of thermionic emission of both elements and, accordingly, their temperatures do not match.

The equality of the emission currents of two different metal objects with the same physical and mechanical properties and the equality of their temperatures follows from the Richardson-Dashman equation:

II-A / CT DCT e. .

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SCA leakage current {average transparency of the potential barrier at the metal – vacuum interface for electron waves; emission constant; constant Boltzmann; electron work function of metal;

base of natural logarithm „

When the bridge is balanced, i.e., the emission currents of measurement object 7 and reference element 6 are equal, the voltage between points C and D is zero and the controlled current source 9 maintains the temperature of reference element 6 equal to the temperature of measurement object 7. model element 12 registers the temperature of model element 6 equal to the temperature of the measurement object 7 °. If the temperature of the measurement object 7 changes, for example, it decreases, the emission current in the circuit decreases. At the input of the DC amplifier 9. The error signal is amplified and fed to the input of the controlled current source 9. The electrical power at the output of the controlled current source decreases and the temperature of the reference element 6 decreases accordingly. The temperature of the object to be measured.

The implementation of a fixed model element in the form of a metal object, which is equivalent in physicochemical properties to the shape and dimensions of the cross section of the metal object being measured, and the execution of an additional measuring electrode identical

in terms of construction and material, the measuring electrode allows minimizing the temperature difference between moving and stationary objects with the equality of their thermionic emission currents.

Due to the fact that all elements of the measuring circuit are located in one vacuum chamber, the stationary model element and the movable element are made of the same material, the measuring electrodes are identical, the degree of vacuum does not affect the measurement results, and the material and geometric dimensions of the moving body long metal object

The introduction of an additional measuring electrode and an exemplary stationary element makes it possible to compare the currents of thermionic emission of a model element and a moving lengthy metal object, which in turn allows, when the currents of a sample element and a moving lengthy metal object are equal, determine the temperature object on the temperature of a stationary model element in the usual high-precision way using a thermocouple and thus increase temperature measurement accuracy.

The use of the proposed device also reduces the laboriousness of the measurement process, it becomes possible to automate the measurement process and stabilize the heating temperature by using the unbalance signal of the measuring bridge for the control unit.

voltage control of the heater.

Claims (1)

Invention Formula A device for measuring the temperature of metal objects in vacuum, containing a measuring electrode placed in a vacuum chamber, a source of direct voltage and a contacting device, so that, in order to improve the measurement accuracy , it is equipped with an exemplary element, an additional measuring electrode, a DC amplifier, a controlled current source, a thermocouple, a thermopower meter and two resistors, while the series-connected resistors, an exemplary element, will complement A measuring electrode, a contacting device and a measuring electrode are connected by a bridge circuit, one of the diagonals of which includes a constant voltage source, the other is a DC amplifier, the output of which is connected to the input of a controlled current source, the sample element is connected to the control output current source, and the thermocouple is mechanically connected to the model element and connected to a thermometer EMF, and the model element is made in the form of a metal object equivalent to -mechanical properties sectional shape and size was measured emomu metal object, and the additional measuring electrode is identical in construction and materials of the measuring electrode " 7 .LZ m Phie, 2