JPS6050443A - Temperature controlling apparatus for thermal analysis - Google Patents

Abstract

PURPOSE:To make thermal analysis accurate and to reduce the amount of consumption of liquid nitrogen, by linking a heat insulating container and a sample holder to a low temperature device through heat conductive members, and performing program temperature control. CONSTITUTION:A needle valve 19 is adjusted so that the level of liquid nitrogen 17 in a space for conductive members 14 and 15 becomes a specified level. A sample holder 1 is contacted to the nitrogen 17, and its temperature is detected by a thermocouple 5. The detected output is inputted to a program temperature controlling device 25. A heater 10 is heated by the output of the controlling device 25. The temperature of the holder 1 is changed at a programmed decreasing speed. A container 6 is contacted with the nitrogen 17 through the member 14. Its temperature is detected by a thermocouple 21. The detected output is compared with the output of the thermocouple 5. A heater 11 is heated by the output of a temperature controlling device 26, and the temperature is changed with the same temperature change of the holder 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a temperature control device for thermal analysis used in a differential scanning calorimeter or the like.

In conventional adiabatic differential scanning calorimeters, when thermally analyzing a sample by lowering its temperature, the temperature of the sample is lowered by cooling the adiabatic container, but it is difficult to make the sample holder symmetrical. Therefore, a temperature difference occurs between the sample and the standard sample,
Thus, the base line of the temperature difference was likely to fluctuate, resulting in the inconvenience that thermal analysis of the sample could not be performed accurately. Furthermore, with conventional low-humidity equipment that lowers the temperature of the sample, the rate of drop in sample temperature changes exponentially, so when lowering the sample temperature linearly, the heater The heating of the sample had to be controlled by using a method, which resulted in the inconvenience that thermal analysis could not be performed accurately.

The purpose of the present invention is to eliminate such inconveniences, by connecting an insulating container and a sample holder housed in the insulating container to a low-humidity device via a heat conductive member, heating the sample holder at 7J11, and programming the sample holder. The second invention is characterized in that the temperature is controlled so that the temperature of the insulating container and the sample holder is the same as that of the sample holder. The coated cylindrical heat conductive member and the axial heat conductive member inserted through the member are respectively connected, and both members are immersed in the liquid voice in the Dua bottle, and the space between the two members, which is closed at one end, is opened. It is characterized in that it communicates with the outside via a regulating pulp, and controls the temperature of the sample holder by heating it, and also controls the humidity of the heat-insulating container so that it has the same temperature as the sample holder.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 1, (1) is a heat-conductive sample holder, which includes a sample container +21 and a standard sample container (3).
), and a thermoelectric element (4) for measuring the temperature difference between the sample and the standard sample is fitted between them.
In addition, a thermocouple (5) for measuring the standard sample container (sample holder temperature) is attached to the lower part, and a heat conductive pedestal (9) is attached to the heat insulating container (6) via the heat insulating member f71 (81). The heat insulating container (6) is for insulating the heat of the sample from the outside air, and has a heater 0υ on the outer periphery and is placed on a fixed heat conductive substrate a. A cylindrical heat conductive member α whose outer periphery was covered with a heat insulating material α4 and a shaft-shaped heat conductive member α1 fitted into the member (141) were placed below the base board and the pedestal (9), respectively. Both members (141 (15)) are connected to the following cryogenic equipment (16+), and each is independently installed in a heat insulating container (141 (15)).
6) and the sample holder tl+ were cooled.

The cryogenic device ae includes a dual bottle filled with liquid nitrogen (17), and a needle that adjustably opens a space closed at the upper end between the cylindrical heat conducting member circle and the axial heat conducting member α■ to the outside air. It consists of a pipe (20) in which pulp a1 is inserted, and when the sample holder (1) is heated by a heater [01] or slowly cooled down, the needle valve is closed and the liquid level in the space is lowered. Place the member α40 at the lowest end, and when rapidly cooling, close the needle valve (
]9 is opened and the liquid level in the space is adjusted to 081.
When the level is in between, adjust the needle pulp σ) so that the level of liquid nitrogen Q7) in the space becomes an appropriate level.

The heater αfil(lυ, thermoelectric element +41, thermocouple (5), and thermocouple Ci! attached to the inner wall of the heat-insulating container (6)).
l) is drawn out to the outside via a tube (221), and as shown in the second figure, the output of the thermoelectric element (4) is sent to a recorder (2 (a), etc. via an amplifier (to), and the temperature of the sample and standard sample is measured. In addition, the heater aα is controlled by a known program controller seat to which a thermocouple f51 is connected, as shown in the figure, so that the temperature of the standard sample can be adjusted according to the program. The temperature was changed according to the program set by the temperature controller (C).The heater 0υ was also connected to a known temperature controller (H) connected to the heater 18 (5) as shown in the figure. It is controlled by the output of the thermocouple (
5) and the CD, and therefore the temperature difference between the sample holder (1) and the heat insulating container (6), was controlled to be zero.

Next, its operation will be explained.

The needle pulp 01 is adjusted so that the liquid level of liquid nitrogen αη in the space between the heat conducting member (1) and (1) becomes a predetermined level.

Since the sample holder (1) is in contact with the liquid nitrogen Q7) via the pedestal (9) and the shaft-shaped heat conducting member Q51, its temperature tends to drop rapidly according to the heat conducting resistance, but the temperature is lowered by the thermocouple ( 5), its output is input to the program temperature controller (251), and the output of the controller (c) heats the heater (101), so the temperature of the sample holder (1) is controlled at the programmed rate of descent. Change.

Since the heat insulating container +61 also comes into contact with the liquid nitrogen αη via the base α force and the cylindrical heat conducting member (14+), its temperature tends to drop rapidly in accordance with the heat conducting resistance, similar to the sample holder il+, but the temperature is lowered by the thermocouple. The output of the thermocouple (5) that detects the temperature of the sample holder (1) is compared with the output of the thermocouple (5), which detects the temperature of the sample holder (1). is heated, the temperature of the insulated container (6) decreases at the same temperature as that of the sample holder (1).Therefore, there is no temperature change between the sample holder (1) and the insulated container (6). There is no temperature difference between the sample and the standard sample due to the asymmetry of the shape of the sample holder (1), and the baseline thereof does not fluctuate.

To increase the cooling rate of the sample, use the needle valve (l!
1 fully open to raise the liquid level of liquid nitrogen in the space.
When the liquid level in heat conducting member Q is at the same level as the liquid level in heat conducting member Q, adjust the needle valve (11 in the blocking direction
It should be near the lower chrysanthemum of 41 (15).

If you perform the operations described above when slowly lowering or increasing the temperature of the sample, you will need less power to apply to the heater (Itll), and the amount of liquid nitrogen αD evaporated will be smaller, resulting in less heater power. As a result, temperature fluctuations due to power fluctuations will be reduced, and errors in thermal analysis will be reduced.

In addition, when the sample is cooled with liquid nitrogen aη via the heat conducting member (151), as the temperature decreases, liquid nitrogen αD
Since the amount of evaporation of the liquid nitrogen decreases, the liquid nitrogen level in the space between the heat conducting member and U rises higher than the liquid level in the bottle, increasing the temperature of the liquid sample. When performing thermal analysis by lowering the temperature linearly, fluctuations in temperature are reduced and errors in thermal analysis can be reduced.

As described above, according to the present invention, the heat insulating container and the sample holder are each connected to a low temperature device via a heat conducting member, and the sample holder is heated to control the programmed humidity, and the thermal analysis is performed using the heat insulating container as the sample holder. In addition, the heat insulating container and sample holder are connected to a cylindrical heat conducting member and a shaft heat conducting member, respectively, and both members are immersed in liquid nitrogen, and the space between the two members, which is closed at one end, is closed using an adjustable valve. Because it communicates with the outside through the

[Brief explanation of the drawing]

FIG. 1 is a sectional view of an embodiment of the present invention, and FIG. 2 is an electrical circuit diagram thereof. fil...Sample holder (5)...Thermocouple (6
)...Insulating container (71 (81... Insulating member (9)
... Frame (101αυ...Heater α2...Group
Board (141Q51...Heat conduction part aQ...Cryogenic device (17>...Liquid nitrogen 0 barrel...During bottle H
・・・21 dollar nokuru ゛(2υ...thermocouple (
c)...Program temperature controller c2e...2 people outside the temperature controller Figure 1 Figure 2 cI

Claims (1)

[Claims] 1. A heat insulating container and a sample holder housed in the heat insulating container are each connected to a low temperature device via a heat conducting member, the sample holder is subjected to program humidity control according to 7JII, and the heat insulating container is A temperature control device for thermal analysis characterized by controlling the temperature so that the humidity is the same as that of the sample holder. 2. Connect a heat insulating container and a sample holder housed in the heat insulating container to a cylindrical heat conducting member whose outer periphery is covered with a heat insulating material and a shaft heat conducting member inserted through the member, and connect both members to a dual bottle. 1. A temperature control device for thermal analysis, characterized in that the device is immersed in liquid nitrogen within the temperature range, and the temperature is controlled so that m=temperature for both parts.