SU1704052A1 - Device for determining thermophysical properties of materials - Google Patents

Description

The invention relates to an experiment; ; , whose thermophysics can be used to determine thermophysical characteristics of various materials.

It is known) St, which is used to determine the thermophysical properties of materials, containing a working chamber /, a calorimetric cell, protective heat shields. the base is the placement of a kzlorimetric chip cell, a system of security heaters, a sakumirovani system, and automatic maintenance of a predetermined thermal mode of the working chamber. The placement of the calorimetric cell based on the call required the introduction of

the design of the system of guard pa- ravtels, which the creature HI.O complicates the device.

The closest in technical essence and the achieved positive result is a device for determining the heat of the physical properties of materials, containing a working chamber, a calorimeter cell adiao-sp, suspension chg, lsr1i .-. 5TЈ, pches; - ki and adiabatic screens, cucres s rlku- pleasing. ipodderl This adiabatic regime.

The disadvantage of this device .; YAZLRSTSYA the difficulty of replacing the site, the need for disassembling the working chamber

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for yc-anoiu.H and removal of the sample from the calorimetric cell. Complete disassembly of the device before each sample change dramatically reduces its reliability and performance.

The aim of the invention is to improve the reliability of the device and simplify the replacement of samples without reducing the measurement accuracy.

The goal is achieved by the fact that in a device containing a working chamber, a calorimetric cell, adiabatic screens, a suspension of a calorimetric cell and adiabatic screens, an evacuation system and adiabatic maintenance, the suspension is made of a thin walled leakproof tube passed through an adiabatic mode screens, with an internal diameter corresponding to the diameter of the calorimetric cell, for-. at one end of the pipe, on

.-. i; .c.v. the surface of which is fixed. They have screens, and inside the pipe there is a sample holder, on which heat screens are successively fixed, which are in thermal contact with the pipe wall and form closed thermal contours with adiabatic screens. Additional heat shields that are in thermal contact with the pipe wall can be chipped on the sample holder, and thermal compensators in the plane of the shields connected to the head-holding system of adiabatic modes -, -, can be installed on the outer surface of the pipe. In addition, the internal cavity of the pipe is connected autonomously with a vacuum system: c; vac1 K.

Performance of suspension is quantitative with. Oh, Y-: SJI and zdiobaticheih.ih screens in;. ;;:. snkstennoy sealed pipe on.: gs -:; -: t exclude depressurization of the rammer and disassembly of adiabatic e-; .iiOD.a iped: n10 heat shields inside Tj, ru provides the necessary dia- (Zagloatsiya calorimetric cell.: -:; sk, s additional heat shields t: oc together with thermal compensators g eeuLuaer quality adizbatieztsii.

The drawing shows a constructive scheme of the proposed device.

The device contains a calorimetric cell 1, adiabatic screens 2 and 3, a hermetic working chamber A, a thin-walled hermetic pipe 5, a sample 6 of the material under investigation, thermal compensators 7–9, heaters 10 of the calorimetric cell, thermal screens 11–15, a sample holder 10, heaters 17

thermal compensators with temperature sensors.

The device contains a working adiabatic screens 2 and 3 and calorimeter cell 1, located in chamber A. The suspension of calorimetric cell 1 and adiabatic screens 2 and 3 is made in the form of a thin-walled sealed pipe 5 with an internal diameter corresponding to

0 to the diameter of the calorimetric cell 1, about which sample 6 is found. Pipe 5 is passed through adiabatic screens 2 and 3 and is fixed by one of its ends with a calorimetric cell. Inside pipe 5, the holder 16 of sample 6 is mounted, and on the external surface of the pipe are adiabatic screens 2 and 3. On the holder 16, there are successively fixed thermal screens 11 -) 5 and thermal compensators 7 - 9 with heaters 17, which contain temperature sensors perature. The holder 16 is made of low heat conductive ceramics with a small cross section. Thermal compensators 7–9 and heat shields 11–15 are in thermal contact with the wall of pipe 5. In this case, heat shields 11–15 form closed thermal contours with adiabatic shields 2 and 3. The internal cavity of the pipe 5 is connected to a vacuuming system (not shown).

The device works as follows.

Sample 6 is placed inside the calorimetric cell 1. With the help of

5 heaters 10 located on the calorimetric cell 1, adiabatic screens 2 and 3, heat screens 11-15 and heat compensators 7-9 support the adiabatic mode of the device.

0 The temperature of heat shields 11-15 at the wall of pipe 5 is equal to the temperature of the corresponding element located on the outer surface of the pipe 5. So the temperature of the heat shield 14 at the wall of pipe 5

5 will correspond to the temperature of the adiabatic screen 3. With this, the heat shield 14 forms with the adiabatic screen 3 a closed thermal circuit, which creates a stable adiabatic mode

0 device operation.

Good thermal contact between the heat shields 11-15 and the inner surface of the pipe 5 is provided with a heat-resistant heat-conducting lubricant. In that

In case of a reliable thermal bridge is formed from the heat shields to the adiabatic shields. When the adiabatic mode of the calorimetric cell cannot be maintained, connect thermal compensators 7–9, equipped with heaters 17. With the help of

Adiabatic maintenance systems (not shown), which includes a temperature regulator and an electronic unit, ensure equal temperatures between the compensator and the heat shield. Improving the aliabatization of the calorimetric cell 1 in the direction of the pipe 5 can also be ensured by connecting the internal cavity of the pipe 5 to the vacuum system and the creation of a vacuum in this cavity.

Sample 6 from calorimetric cell 1 is changed as follows. The internal cavity of the pipe 5 is disconnected from the vacuum system. From the cavity of the pipe 5 is removed the holder 16, on which the heat shields 11 are fixed

- 15 and test sample 6. The sample is replaced, and the holder 16 with the new sample and heat shields 11-15 is inserted into the pipe 5 again.

As shown by experimental testing of the prototype device, the time required to replace the sample is 300

- 500 s, and the time taken to bring the device to the adiabatic mode does not exceed 10 4s. In known devices, the first time indicator is almost an order of magnitude larger than in the proposed device, and the second is about 2-Zraz.

The reduction in the time the device takes to the adiabatic mode is due to the fact that during the sample change, the vacuum between the adiabatic screens is maintained and the sample change time itself is substantially less than in known devices. The elimination of a complete disassembly of the working chamber for changing the sample allows increasing the reliability of the device, while reducing the time required to change the sample and go to the adiabatic mode increases productivity while maintaining the specified accuracy of determining the desired characteristics.

Claims (1)

Claims An apparatus for determining the thermophysical properties of materials, comprising a working chamber, a calorimetric cell, adiabatic screens, a calorimetric cell suspension and an adiabatic screen, an evacuation system and maintaining an adiabatic mode, characterized in that, in order to improve the reliability of the device and simplify the replacement of samples reducing the accuracy of measurements; in it the suspension is made in the form of a thin-walled pressurized tube passed through adiabatic screens with an internal diameter corresponding to the diameter of the calorimetric cell, mounted on one of the ends of the pipe, on the outer surface of which adiabatic screens are fixed, and inside the pipe there is a sample holder, on which thermal screens are successively fixed, which are in the thermal circuit with the pipe wall, and some of them form adiabatic screens are closed thermal circuits, and some are in contact with thermal compensators installed on the outer surface of the pipe in the plane of the screens and connected to the supporting system Jani adiabatic regime, the inner cavity of the pipe autonomously connected to the evacuation system. And vacuum system