CS251477B1

CS251477B1 - The method of continuous measurement of the temperature dependence of the physical quantity of metallic materials at deep temperatures and the apparatus for its performance

Info

Publication number: CS251477B1
Application number: CS842514A
Authority: CS
Inventors: Stanislav Vertal
Original assignee: Stanislav Vertal
Priority date: 1984-04-02
Filing date: 1984-04-02
Publication date: 1987-07-16
Also published as: CS251484A1

Abstract

Riešenie sa týká spůsobu a zariadenia pre kontinuálně meranie teplotnej závislosti fyzikálně] veličiny, například elektroodporu kovových materiálov, pri teplotách pod izbovou teplotou a pri hlbokých teplotách a rieši operativně, variabilně a nenáročné meranie a vyhodnocovanie závislosti. Na tepelne izolovaná vzorku od okolia, aktivovaná na meranie, sa působí chladiacim plynom, ktorého teplota sa plynule znižuje, a to v závislosti od plynule sa meniaceho množstva teplého plynu, prechádzajúceho kontaktně skvapalneným plynom. Teplota i změna fyzikálnej veličiny vzorky sú merané a zaznamenávané súčasne, a to fotoelektrickým spůsobom, pričom meranie sa robí pri zvolenej jednej alebo různých rýchlostiach plynulého ochladzovania. Zariadenie pozostáva z kryostatu s prívodnou rúrkou zavedenou nad hladinu skvapalneného plynu v termoflaši, z prívodnej rúrky vybavenej rozptytovacou fritou a opatrenej regulačným ventilom s ovládacou prestavovatetnou převodovkou. Vzorka v kryostate je vybavená termočlánkom a spoločným meracim a zaznamenávacím prístrojom pre súčasné meranie změny zvolenej fyzikálnej veličiny a teploty vzorky zápojenej na aktivačný zdroj.The solution relates to a method and a device for continuous measurement of the temperature dependence of a physical quantity, for example the electrical resistance of metallic materials, at temperatures below room temperature and at low temperatures and solves the measurement and evaluation of the dependence in an operational, variable and undemanding manner. A sample thermally insulated from the environment, activated for measurement, is acted upon by a cooling gas, the temperature of which is continuously reduced, depending on the continuously changing amount of warm gas passing through the contact liquefied gas. The temperature and the change in the physical quantity of the sample are measured and recorded simultaneously, by a photoelectric method, while the measurement is made at a selected one or different rates of continuous cooling. The device consists of a cryostat with a supply tube introduced above the level of the liquefied gas in the thermos flask, a supply tube equipped with a scattering frit and provided with a control valve with a control adjustable gearbox. The sample in the cryostat is equipped with a thermocouple and a common measuring and recording device for simultaneous measurement of the change in the selected physical quantity and the temperature of the sample connected to the activation source.

Description

251477

BACKGROUND OF THE INVENTION The present invention relates to a method of continuously measuring the temperature dependence of a physical quantity, for example, the electrical resistance of metallic materials, at temperatures below room temperature and at deep temperatures, such as to implement it, and operatively, variably and undemandingly measure and evaluate dependency. physical quantities from temperature. A point method is used to determine the dependence of physical quantities of metal materials on temperature. By this method, it is necessary to adjust the temperature of the metal sample, after stabilization of the value of the physical quantity and the procedure to be repeated according to the desired number of measurements, from the measured values the temperature dependence of the physical quantity. The process of running, laborious, dependent on temperature stabilization and actually measuring is discontinuous. Especially difficult to find out, in particular, the not-known locally deviations of the temperature dependence of a physical quantity and then determine their hearing temperature or their narrow temperature interval especially in the deep Determination of local changes in the temperature dependence of the physical quantity on the metallic materials contributes to new knowledge of changes in mechanical properties and their causes, since sometimes both changes coexist in the same temperature range.

The above-mentioned drawbacks are solved by the problems of the continuous measurement of the temperature dependence of the physical quantity, for example, the resistance of the metallic materials to the high temperatures and the apparatus for its implementation according to the invention.

According to the invention, the continuous change in the temperature of the cooling gas, and thus the continuous change in the temperature of the sample activated for measurement, is regulated by a continuous change in the amount of hot gas passing through the contact gas. At the same time, changing the sample temperature and changing the temperature-dependent physical factor are measured simultaneously and recorded electrically at different cooling rates selected.

The principle of the device according to the invention, consisting of a cryostat with a cooling gas supply pipe introduced above the liquefied gas level in the thermo-bottle, is that a hot gas supply pipe is provided, provided at the bottom with a thermo-scrubber frit and provided with with a control valve with an adjustable gearbox. A thermocouple, a photo-electric meter is connected to the sample to be measured, stored at the same time for changing the physical quantity and sample temperature and activating the source. The advantages of the invention are that the change in the temperature of the sample during the cooling process is continuous, the measurement of the temperature dependence of the physical quantity is continuous, time-consuming, the dependence of the physical quantity and simultaneously the temperature makes it possible to subtract the instantaneous value of the physical the quantity and its corresponding temperature, as well as the local variation of the physical quantity and its respective temperature interval and the rate of change of the temperature of the sample and the variation of the physical quantity depending on the temperature are variable. An exemplary embodiment of the method of the present invention is shown by detecting the dependence of the metal sample support on temperature T, as well as any local anomalies in the temperature range below room temperature and temperature, continuously at time t.

At the bottom of the thermo-flask filled with liquefied nitrogen, gas nitrogen is fed to the room temperature, which is cooled by contacting it through a liquefied nitrogen with simultaneous pulse-free evaporation of the liquid nitrogen. The cooling gas tube from the space above the surface in the thermo-flask is fed to the cryostat to a sample of the metal at the end of which there is unidirectional stabilization. The amount of gas nitrogen fed to the bottom of the thermo-flask is continuously controlled, thereby altering the temperature of the sample resulting in a change in the loss of AU tension on the sample ends as a direct proportion of the electrical resistance value at time t. Dependencies of AU - f (ie, T = f (t) are simultaneously displayed by the photoelectric method on the record. At the same time, the current record of both dependencies is controlled by fluency cooling, ie by checking whether the eventual change in AU value has occurred If the local change in temperature does not occur, then this cause can only be determined by the local change of electro resistor, such as the physical "anomaly." the continuous dependence of the AU - f (T), or even the complete temperature dependence of the specific electro resistor, is shown in the accompanying drawing, where a schematic arrangement of the elements of the device is shown.

The measured sample 1 is embedded in the cryostate 2 into which the nitrogen gas cooling tube 3 opens into the thermo-flask 4 with the liquid nitrogen. The gas nitrogen supply pipe 5 is provided with a regulating valve 6 connected to the motor-driven transmission 7, the pipe 4 is introduced to the bottom of the thermo-flask 4 and at the end is provided with a frit 8. A thermocouple 9 and a common photo-electric recording apparatus are connected to the sample 10 the temperature and variation of the physical quantity and the stable source of unidirectional voltage.

Sample 1 in cryostate 2 is energized for measurement after the unidirectional stable source 11 is connected. The appropriate cooling speed is adjusted to the gear 7, the needle control valve 6 and the nitrogen gas is admitted to the thermo-flask 4, of which

Claims

The amount of fluid is continuously varied with the opening of the valve 6. At the same time, the photoelectric meter 10 being connected records the temperature of the sample at the same time and the change in voltage drop over time. The triggered system operates independently until the lowest possible 776 temperature at which the sample cooling is removed. The measurement can be continued by continuously warming the sample left in the cryo after the continuous deflection is stopped. The records obtained during continuous cooling and warming are evaluated. OBJECT

1. A method for continuously measuring the temperature dependence of a physical quantity, for example a metal material resistance, at temperatures below room temperature and at high temperatures, where a physical quantity is thermally insulated from the surroundings to activate the sample, a cooling gas is applied characterized in that a continuous change in the temperature of the cooling gas is controlled by a continuous change in the amount of hot gas passing through the liquefied gas, wherein the temperature change of the sample and the change in the temperature-dependent physical quantity measured simultaneously and recorded electrically at one or different o-cooling rates selected and the measured temperature measured, the temperature dependencies obtained are evaluated.

Apparatus for carrying out the method of (1), comprising a cryostat, a cooling gas tube, introduced above the liquid gas level in a thermofibre, characterized in that a hot gas inlet tube (5) is introduced into the thermofoil (4). equipped with a diffusing frit (8) at the bottom of the thermoplastic flask (4) and a control valve [6] with a controllable gearbox (7 J, with a feed tube (1j) in the cryostate [2] 3), a thermocouple (9) is connected to a photoelectric measuring device (10) for simultaneous measurement of the physical quantity and temperature of the sample and the activation stable source (1 sheet of drawings