SU1303928A1 - Device for differential-thermal analysis - Google Patents

Abstract

The invention allows the differential thermal analysis of fluorides in an atmosphere of hydrogen fluoride using a dispenser for changing the composition in a crucible, and also expands the range of heating rates and increases the sensitivity of the analysis. Opened molybdenum crucibles with a sample and a standard are installed in the channels of the molybdenum block, which is mounted on a molybdenum rack. The rack passes through the inner cylinder of the insulator. The conclusions of the simple and differential thermocouples pass between the inner and outer cylinders of the insulator. The positive thermoelectric electrode of the combined thermocouple is made of a thermoelectric tungsten-rhenium-5 wire in the form of a ring passing through both cavities of the block and two negative thermocouples. 2 Il. (L

Description

The invention relates to physico-chemical analysis.

The purpose of the invention is to provide research in the atmosphere of gaseous hydrogen fluoride, increase the sensitivity of the analysis and expand the range of heating rates.

FIG. 1 shows the proposed device; in fig. 2 shows section A-A in FIG. one. ,

The device contains a molybdenum block 1 with cavities for the test substance and the reference,

Unit 1 is mounted on a molybdenum thrust 2, which passes through an insulator consisting of an inner 3 and an outer 4 gauge. The conclusions of the simple 5 and differential 6 thermocouples, of tungsten-rhenium-20 wire, pass between the inner 3 and outer 4 cylinders (made of aluminum oxide), which are located in the low temperature zone (20-100 ° C). The positive thermoelectrode 7 of the combined thermocouple, made of a tungsten-rhenium-5 thermoelectrode wire, passes as a ring through both cavities of the thermostat and through two negative thermoelectrodes,

I have at the end of the form of a spiral of two or three turns and the combined thermocouple forming working junctions 8 and 9. In the zone of high temperatures (more than 100 ° C), ceramic insulators are absent. The positive thermoelectrode 7 is at a temperature that falls within the temperature range of the sample and the reference, which to a certain extent compensates for the thermo-emf arising

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20

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due to the thermal imbalance between the points of the sample and the standard, regardless of the presence of the thermal effect.

The device works as follows.

With a linear increase in temperature in the zone where the measuring cell is installed, a certain gradient arises: temperature, i.e. Each point between the sample and the reference has its own temperature. The higher the growth rate of the terahertura, the greater its gradient. The junctions of 8 and 9 thermocouples placed in the sample and the reference record this temperature gradient. At the same time, the thermoelectrode wire in the form of a ring reduces the differential EMF resulting from the temperature gradient due to thermal diffusivity,

Claims (1)

Invention Formula A device for differential thermal analysis, containing a metal block with cavities for the sample under study and a reference, a hollow and two negative thermoelectrodes that form a combined thermocouple, characterized in that, in order to study a hydrogen fluoride gas in the atmosphere, sensitivity of the analysis and expansion of the range of heating rates, the positive thermoelectrode is executed in the form of a ring passing through both fields of the block and two negative thermoelectrodes. one phi5.2