RU220612U1 - Differential thermal analyzer with controlled heating and cooling rates - Google Patents

Abstract

The utility model relates to the field of physical and chemical analysis, namely to differential thermal analysis devices for recording thermal effects.

Differential thermal analyzer with controlled heating and cooling rates, consisting of a heating furnace, a gas system for supplying inert gas to the furnace chamber, a control unit and digital signal conversion, a data processing and transmission unit, which is part of the control unit, equipped with an interface that allows data reception/transmission, a differential unit for determining the thermal effect of the material under study, a heat-conducting ceramic substrate, a measuring cell consisting of 2 pairs of at least 7 serially connected thermocouples. 2 ill.

Description

The utility model relates to the field of physical and chemical analysis, namely to differential thermal analysis devices for recording thermal effects.

Several basic differential thermal analyzer devices are known from the current state of the art.

A utility model is known (RF patent No. 181100), consisting of a heating furnace with a control thermocouple and a sample measuring thermocouple, a heating mode control unit, which contains a unit for setting the furnace heating mode and a furnace heating amplifier, a differentiation unit, a summation unit, a subtraction unit and a recorder. The disadvantage of which is the absence of a sample cooling control unit.

There is an invention (RF patent No. 1450589) in which the differential thermal analyzer device contains a reaction chamber in which the sample is sprayed with a sprayer, which helps create an isotropic thermal environment. The disadvantage of this patent is the complexity of the design and labor-intensive sample preparation before testing.

There is a known utility model (RF patent No. 48638), in which the device for differential thermal analysis is a fully computerized installation. The heating element design allows rapid cooling to reduce the time between measurements. The disadvantage of this useful model is the lack of controlled cooling to study thermal effects during the cooling process.

The closest known analogue is patent US5288147, which describes a device for a differential thermal analyzer with differential thermocouples connected in series. The differential thermal analysis sensor contains a flat substrate on which are located thermocouples, which are located around the periphery of the substrate such that each junction coincides with a corresponding other junction. The disadvantage of this patent is the technological complexity and labor intensity of manufacturing the device.

Thus, the technical problem to be solved by the proposed utility model is the development of a differential thermal analyzer with controlled heating and cooling rates.

The solution to this technical problem is achieved by the fact that the differential thermal analyzer device contains a furnace for heating in the temperature range from 25 to 700°C, in which heating elements are located around the furnace body without internal insulation, which ensures rapid heating from 5 to 40°C per minute and cooling, a measuring cell is also placed in the furnace, containing two pairs of at least 7 thermocouples connected in series to amplify the differential signal, and finally, the design of the device contains an inert gas supply unit selected in such a way that there is a uniform supply of gas into the furnace chamber for uniform heating and cooling at a rate of 5 to 40 °C per minute.

The technical result of the claimed utility model, provided by the above set of features, is an increase in the output signal due to an increase in the number of thermocouples connected in series, as well as a decrease in the signal noise level due to the location of the cold junctions directly in the hot zone of the furnace.

Description of the figures.

Fig. 1 – Diagram of a heating furnace, consisting of chamber 1, heating elements 2, base 3, process cover 4, gaskets 5 and 6, measuring cell 7 and cover 8.

Fig. 2 – Schematic representation of a utility model device, consisting of a heating furnace 9, a gas system (means) for supplying inert gas 10, a control unit 11, a digital converter 12, a control and measuring thermocouple 13 and a measuring cell 7.

The utility model device consists of a heating furnace 9, a gas system (means) for supplying inert gas to the furnace chamber 10, a control unit 11 and a digital converter 12, a control and measuring thermocouple 13 for determining the temperature of the samples under study, a measuring cell 7, consisting of two pairs at least 7 serially connected thermocouples to determine the thermal effect of the material under study, a substrate made of heat-conducting ceramics, to obtain high sensitivity of the measuring cell and controlled heating and cooling rates.

The device shown in FIG. 1, consists of a heating furnace 9, chamber 1, base 3, and cover 8, which are made of stainless steel and gaskets 5 and 6, made of thermal insulating wool, for placing the test sample in the measuring cell 7, consisting of a metal base and a ceramic insert with control and measuring thermocouples 13; the furnace and the measuring cell are connected to a digital converter 12 using a cable, which in turn is connected by a cable to a control unit for setting test modes 11 and a heating furnace 9, to which a gas system (means) is connected using metal tubes for supplying inert gas to the chamber furnace 10. The heating element 2 can be made, but is not limited to, from a nichrome alloy.

A differential thermal analyzer with controlled heating and cooling rates, shown in Fig. 2, consists of a heating furnace, a gas system (means) for supplying inert gas to the furnace chamber, a control unit and digital signal conversion, control and measuring thermocouples for determining the temperature of the samples under study , a differential block consisting of two pairs of at least 7 serially connected thermocouples to determine the thermal effect of the material under study, a measuring cell made of heat-conducting ceramics. Setting the experimental parameters, namely, heating temperature, heating rate, cooling rate, as well as data collection and processing are carried out using special software, which is performed by a data processing and transmission unit, which is part of the control unit, in turn connected to digital converter unit using an electrical connection cable. The control unit is equipped with an interface that provides the ability to receive/transmit data (in the particular case of USB, also in the particular case of LAN Rj45, but not limited to). A differential thermal analyzer with controlled heating and cooling rates provides the ability to record small thermal effects, as well as controlled heating and cooling capabilities to study the thermal effects of a material as it heats and cools.

A differential thermal analyzer with controlled heating and cooling rates can be used in the following industries: food, chemical, metallurgical, pharmaceutical, etc.

The device works as follows. Before starting the study, the sample under study is placed in the furnace where the measuring cell 7 is located, then the furnace chamber is closed and the experiment parameters are set using a computer program: final heating temperature, heating rate, cooling rate, and also an adjustment is loaded to correctly display the baseline. Next, if necessary, gas is supplied to the furnace chamber and heating is turned on. At this moment, data recording begins and in the program window, in real time, a graph of the signal from the differential thermocouple depending on the sample temperature begins to be displayed. After reaching the set temperature, if recording of the experiment during the cooling process is not required, the furnace heating is turned off, recording stops, and the data is saved to a text file. If it is necessary to obtain experimental data during the cooling process, then after turning off the heating of the furnace, data recording does not stop and gas begins to be supplied at a flow rate that provides the required cooling rate. After cooling to the desired temperature, the experiment stops and the data is saved to a text file.

Claims (1)

Differential thermal analyzer with controlled heating and cooling rates, consisting of a heating furnace with an inert gas supply into the furnace chamber through metal tubes; to which a control unit is connected via a cable, consisting of a digital signal conversion unit and a data processing and reception-transmission unit, equipped with an interface that provides the ability to receive/transmit data, designed to interface with a computer and with a measuring cell device to determine the thermal effect of the material being tested , installed directly in the furnace, including a differential unit consisting of two pairs of at least 7 serially connected thermocouples to determine the thermal effect of the material under study, on which a heat-conducting ceramic substrate is located to ensure high sensitivity of the measuring cell and controlled heating and cooling rates.