SU45973A1 - Vacuum thermoelement - Google Patents

Description

As is known, a conventional vacuum thermoelement has an approximately square characteristic of the dependence of the thermoelectromotive force on the measured current.

Such a characteristic has the disadvantage that there is a large unevenness in the sensitivity of the instrument in its various parts. This unevenness is especially significant at the bottom of the curve.

The invention aims to reduce the curvature of the characteristics of the thermoelement, and hence the unevenness of its sensitivity.

In FIG. 1 shows schematically the proposed thermoelement; FIG. 2-comparative characteristics of the proposed and conventional thermocouples.

The essence of the invention 5 is that the ratio between the energy dissipation factors released by the measured current at the point of contact of the thermocouple with the heating wire changes significantly. For this purpose, this place is covered with some substance with increased emissivity, for example, soot, ink, etc. It is significant that the heat removal due to radiation varies approximately in proportion to the fourth power of the temperature, and due to heat conduction in the first.

If we construct the curves of relative thermoelectromotive

to relative measurable

strength

v I

to current - - results are obtained, cat

Some may be seen in FIG. 2 of the drawing, where curve 2 shows the characteristic of a conventional thermoelement, while curve 3, corresponding to the proposed thermoelement, goes higher and has a lower curvature all the way over curve 2.

As a substance with a high emissivity, a substance specifically treated, for example, by oxidation, etching, calcining benzene vapor, gasoline, etc., can be used in the atmosphere.

The subject matter of the invention.

Claims (1)

1. A vacuum thermoelement with a heating thread, characterized in that, in order to obtain a thermoelement characteristic approaching a straight line, at the contact point of the thermocouple with the heating thread, a substance with increased emissivity, for example, soot, ink, etc., is applied. 2, in the thermoelement according to claim 1, use as a substance with increased radiation ability of a substance, specially treated, for example, p, oxidation, etching prokalivanen in an atmosphere of benzene vapor, benzene, etc.