SU905661A1 - Gas thermometer - Google Patents

Description

one

This invention relates to a technique for measuring temperature.

A gas thermometer containing a thermal bulb and an elastic element, connected by a capillary channel with a mercury plug, filled with a mixture of nitrogen and helium til, is known.

The disadvantage of such a thermometer is a narrow range of measured temperatures.

Also known is a gas thermometer containing a thermal bulb connected through a capillary to a thermostatic damping tank, and a thermostatic elastic element in fluid communication with the damping tank through a measuring capillary tube with a mercury plug G23.

The disadvantage of this thermometer is the non-linearity of the scale.

The purpose of the invention is to linearize the scale of the gas thermometer.

This goal is achieved by the fact that in the thermometer the measuring capillary tube with a mercury plug is made with an engraved cross section, and the cross section area is determined by the formula

ST

S. PG I

where C is a parameter defined by the volumes of the thermometer elements and the scale of the scale; T is the temperature of the temperature control of the damping tank and the elastic element; measured temperature. This difference provides a linear scale.

The drawing shows a manometric gas thermometer, a cut.

Claims (2)

A manometric gas thermometer consists of a thermal bulb 1 connected by a capillary 2 to a damping tank 3, an elastic element k connected to a damping tank by an alternating 390 section 5 capillary tube with a mercury plug 6, scales 7 and 8, and thermostats 9 and 10. Thermometer operation It is based on the thermal expansion of gas in the thermal bottle 1, in which it moves along the capillary 2, and the gas pressure in the damping tank 3 increases. The mercury plug 6 moves in the capillary 5 and the gas pressure increases, in the elastic element t. Moving the mercury plug 6 balances the gas pressure inside the thermometer, and the displacement amount serves as a measure of the temperature j readable on scales 7 or 8. When measuring low temperatures the gas pressure inside the thermometer decreases and the reverse displacement of the mercury plug. While the thermometer's temperature depends on the temperature of the damping tank 3 and the elastic element i, to eliminate such dependence, they are thermostatically controlled. The change in the volume of gas in one of the parts of the thermometer separated by the mercury plug 6, in fractions of the total volume of the capillary 5, is determined by c (if), v (v + va) where С V {V + V-, + Vp is the volume of the capillary 5} the volume of the thermal bulb 1; the volume of the damping tank 3; volume of the elastic element k. Differentiating the expression (1) and putting dx Sd, where S is the cross-sectional area of the cap; -1ll pa, length, we get iU - st di fJT Since the scale must be J -; - const Cn, then the scale factor. The linearity of the scale of the thermometer provides ease of use and the same accuracy of reading the measured temperature anywhere on the scale. By this, the proposed device favorably differs from the well-known Formula of Invention A gas thermometer containing a thermal bulb connected through a capillary to a temperature-controlled damping reservoir, and a thermostatic elastic element communicating with the damping reservoir through a measuring capillary with a mercury stopper, In order to obtain a linear scale of the thermometer, in it the measuring capillary p is made with a variable cross section, the area of which is determined by the formula S, where T is the temperature of the thermostat ovaizmer EMA temperature; coefficient, depending on the volume of the thermometer elements and the scale of the scale. Sources of information taken into account in the examination 1. USSR author's witness ff 373547, cl. G 01 K 5/32, 1971. 2. Copyright certificate CC € P № 712689, cl. G 01 K 5/32, 1977 (prototype).