SU32012A1 - Nickel-Nichrome thermocouple - Google Patents

Description

One of the best tarmic pairs made from non-precious metals is nowadays nickel-chrome vapor. With cheap material, the eye has a large electromotive force and is able to withstand high temperatures (up to 1300 °). Its negative quality is the fact that nickel, after several heatings, does not change completely in appearance and does not show even the slightest trace of floating, makes it very fragile. When such a thermocouple is already moving in and out of place, nickel often breaks, and the thermopair becomes unusable, sometimes even after several hours of operation.

There is a special kind of nickel fused in a void that does not possess this nasty brittleness property. Thermocouples from such a nickel are very vigorous debts, but they are also expensive.

The production of a nickel-nichrome thermocouple, which would have durability, is rather difficult, therefore, thermocouples are made either from copper-constantan or from nichrome-constantan. When operating such thermocouples, it is necessary to count278

However, these thermocouples do not withstand temperatures above 950 °. With occasional increases in temperature above 950 ° C, the thermocouple becomes unsuitable, and not only the thermocouple wires melt, but also the internal protective copper lining. Thermocouple nichrome-constant works a little more reliable.

Based on the foregoing, the author carried out experiments with the aim of obtaining a nickel-nichrome thermocouple capable of serving for a long time, made, however, from ordinary wire.

It was possible to obtain a nichrome thermocouple from ordinary nickel wire, which has sufficient durability.

According to the invention, the nickel branch of the thermocouple, in order to impart mechanical strength to it, is twisted with a special non-insulated wire that supports it. This nichrome support wire is also welded into the hot junction, as is the main branch of nichrome. The other end of the supporting nichrome wire does not reach the cold end of the thermocouple by approximately 1/3 of the length of the tgrmopair. In qualities; the insulators used porcelain tubes with a diameter of 7 l "l, for a length of 100 lgl with an internal channel of 2 mm. For reasons of economy, these tubes are worn on only one nichrome branch of the thermocouple, then the thermocouple branches are wrapped in an asbestos cord and placed in a steel casing.

The wire for thermocouples is taken with a diameter of 1.5 mm, there is no protective copper lining of the thermocouple. The branches of the thermocouple end in a wooden handle, fitted with wire clips.

The thermocouple of such a device has all the good qualities of nickel-nichrome thermocouples, and at the same time it does not have brittleness and brittleness.

The probe, thermocouple, manufactured by the above method, worked in a quenching furnace at a temperature of 800-900 ° with a two-shift operation of the disease without damage.

The subject matter of the invention.

A nickel-nichrome thermocouple, characterized in that the nickel branch of the tsrmocouple is twisted from individuals supporting its uninsulated nichrome wire to give it mechanical strength.