SU1260791A1 - Device for measuring temperature of substance crystallization - Google Patents

Abstract

The invention relates to a physicochemical analysis technique and can be used to measure the crystallization temperature of substances. The purpose of the invention is to simplify the design, increase the reliability, accuracy and speed of measurement. The device contains a sampler with a temperature-sensitive element, mounted in a protective casing. The protective cover in the upper part is connected to a source of cooling air. The sampler is made up of two coaxially arranged cylindrical cups, the cavities of which are communicated through windows in the lower part of the inner cup. The heights and diameters of the glasses are correlated: liD (Hh} d, rf, where H, d is the height and diameter of the inner glass, h, D is the height and diameter of the outer glass. The ratio of the sizes of the glasses ensures complete replacement of the sample in the outer glass . 1 ill. (C (L ND a about with

Description

This invention relates to a technique for physico-chemical analysis of substances and can be used in the chemical, petrochemical, and pharmaceutical industries.

The purpose of the invention is to simplify the design, increase the reliability, accuracy and speed of measurement.

The drawing shows the proposed device for measuring the crystallization temperature of substances.

The device consists of a temperature-sensitive element 1 placed in a sampler, made in the form of two coaxially arranged cylindrical glasses 2 and 3, communicating via windows 4 in the lower part of the internal glass 2.

The height of the inner cup H is greater than the height of the outer cup h, and the diameter of the inner cup d can be calculated by the formula

g- v n'b

Hh

where D is the diameter of the glass.

Such a ratio of sizes ensures the change of the sample in a single measurement cycle. Thermocouple 1 is located below the filling level of the glass 3. The sampler is fixed in the protective casing 5 by means of fastenings 7. The protective casing 5 has the form of a glass, on top of a hermetically sealed lid 6. The casing is made of thermoisol material, eg PTFE. In the lower part, the protective casing is connected via a cable 8 to a tank filled with water, and the upper part - through a pipe 9 with a source of cooling air. The protective cover is immersed in the measured material to such a depth that the sampler is below the surface level of the measured material.

In the initial state, the device is disconnected from the source of cooling air. The internal cavity of the protective casing 5 is filled with the measured solution, the level of which is 5-10 cm above the upper edge of the glass 2. The sampler is completely filled with the measured liquid.

At the beginning of the measurement cycle, the cooling air through the pipe 9 enters the cavity of the protective casing 5 and, through the openings 8, displaces the liquid therein into the surrounding volume. The cooling air pressure is selected so that the solution is completely expelled from the cavity of the protective casing 5. After the liquid is displaced, air flows directly into the surrounding device fluid.

The measuring solution from the upper part of the glass 2 displaces the solution from the glass 3

and fills its volume. The ratio of the sizes of glasses 2 and 3 is such that the volume of the upper part of the glass 2 is equal to the volume of the glass 3, which provides a complete replacement of the sample in the glass 2.

Measuring solution; The probe is in contact with the cooling air entering the internal cavity of the protective casing, which ensures its cooling and crystallization. The temperature of the sample is measured with the help of a sensitive thermocouple 1. When the temperature of the sample being cooled becomes equal to the crystallization temperature, the process of phase transformation of the substance from the liquid to the solid state, accompanied by heat release, begins. Despite the heat dissipation of the cooling air, the temperature of the sample remains constant until the end of the phase transformation. The crystallization temperature corresponds to the characteristic horizontal

0 is a section on the cooling curve recorded by the recording device. Subsequently, the sample temperature continues to decrease below the minimum possible crystallization temperature, which is determined by the minimum concentration value, which is determined by the minimum concentration value for this process. The cooling air supply is stopped.

The solution begins to fill the internal cavity of the protective casing 5. Begins

 The process of heating the sample in the beaker 3. The upper part of the beaker 2 is filled, which, when the cooling cycle is repeated, provides for the change of the sample. When the temperature of the sample becomes equal to the temperature of the substance in the reaction volume, the cooling air is turned on and the cycle is repeated.

five

Claims (1)

Invention Formula A device for measuring the crystallization temperature of substances containing a sampler With a temperature-sensitive element placed in a protective housing connected to a source of cooling air, characterized in that, in order to simplify the design, increase reliability, accuracy and speed, the sampler is made in the form of two coaxially arranged cylindrical glasses communicating through windows in the lower part of the inner cup, the heights and diameters of the cups being correlated hD2 (Hh) d2,,, where H, d is the height and diameter of the inner glasses; h, D - the height and diameter of the outer glass. Air