SU857745A1 - Method of thermocouple inertia determination - Google Patents

Description

I

The invention relates to the metrological assurance of temperature measurements and is intended to determine the inertia of thermocouples, and can also be used to calibrate thermocouples.

A device for measuring the time of thermal inertia of thermoelectric converters is known, which contains a panel with electrical heaters located on it, connected to a source).

A disadvantage of this device is the low accuracy of measuring the inertia of thermocouples due to heat removal and a considerable investment of time.

The closest in technical essence to the present invention is a device for studying the transient mode of thermocouples containing a high-voltage pulsed capacitor, in whose circuit a switch is connected in series, a metal plate that is in contact with the thermocouple under study, and a recorder 2.

However, in the known device it is impossible to determine with sufficient accuracy that the thermocouple is thermal, due to the fact that heat transfer occurs from the heated plate and from the thermocouple through conductors and through the environment.

The purpose of the invention is to improve the accuracy of determining the inertia of thermocouples.

The goal is achieved by the fact that the metal plate is fixed on the insulating dielectric base and is located between the electrodes with a gap, with

10 this base with the plate and the electrodes are placed in a vacuum chamber.

The drawing shows the proposed device.

A device for determining the inertia of 5 thermocouples contains a high-voltage pulsed capacitor 1 to which electrodes 3 and 4 are connected via switch 2 and conductors for pulsed breakdown in vacuum and fixed in the wall of the vacuum chamber. 5, in which a heat insulating dielectric base 6 is also placed, with a metal plate fixed on it. 7 placed with a gap between

electrodes 3 and 4. To plate 7 is attached, thermocouple 8, connected to the recorder 9. The device operates as follows. After the closure of switch 2, pulsed breakdown of the vacuum gaps in chamber 5 occurs. Breakdown occurs at the sites of the electrode 3-metal plate 7, metal plate 7-electrode 4. After all the energy stored in the high-voltage pulse capacitor 1 is consumed to heat the metal plate 7, the arc in a vacuum goes out. The signal from the thermometer 8 is fed to the recorder 9.

The proposed device, in comparison with the known, provides an increase in the accuracy of determining the inertia of thermocouples, since in the metal plate from which the thermocouple is heated, temperature as a function of time is very close to a single jump. This is due to the fact that the metal plate, located in a vacuum, is isolated from any objects to which it could intensively release heat. The device can also be used to calibrate thermocouples, as they very accurately reproduce a single temperature jump.

Claims (2)

Invention Formula A device for determining the inertia of thermocouples, containing a high-voltage pulse capacitor, in whose circuit a switch is sequentially connected, a metal plate in contact with the thermocouple under study, and a recorder, in order to increase accuracy of determining the inertia of thermocouples, the metal plate is mounted on the insulating dielectric base and is located between the electrodes with a gap, while the base with the plate and the electrodes are placed in a vacuum chamber. Sources of information taken into account in the examination 3. USSR author's certificate N 723399, cl. G 01 K 15/00, 1978. 2. Transitional mode of the separated thermocouple. - Henning, Parker Heat Transfer. Proceedings of the American Society of Mechanical Engineers, seri S. T. m 89, G 2 p. 34-35, FIG. 3 (prototype).