JP3248342B2 - Thermal analyzer - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to differential thermal analysis (DT).
A), thermogravimetry (TGA), thermomechanical analysis (TM)
A), a thermal analyzer such as a differential scanning calorimeter (DSC).

[0002]

2. Description of the Related Art In a thermal analysis apparatus, a sample placed in a heating furnace is heated to a temperature of about 1500 ° C., or conversely, cooled from a high temperature state to analyze a change in heat generated in the sample. Generally, in this type of thermal analyzer, a radiation shield for reflecting radiant heat is provided on the outer periphery of the heating furnace, and further, a heat insulating cover is arranged outside the radiation shield.

The radiation shield and the heat insulating cover are made thick and heavy to increase the heat capacity in order to reduce the heat energy loss, and these shields and the cover are connected to a heating furnace to improve the heat retention. When the heating furnace (furnace tube) is cooled, it must be performed from outside the heat insulating cover or radiation shield, and it takes a long time to lower the temperature to near room temperature. I was

Therefore, a thermal analyzer as shown in FIG. 3 has been proposed. FIG. 3 shows an example of a differential thermal analyzer, in which a sample S and a reference sample R are installed at a central portion in a heating furnace 31 and heated by a heater wire 32 wound around the heating furnace 31 (about 1500 ° C.). ) A detector D detects a temperature difference between the sample S and the reference sample R due to a thermal change of the sample.

[0005] The heating furnace 31 prevents energy loss.
It is surrounded by a radiation shield 33 and a heat insulating cover 34.
A gap 38 is provided between the ventilation tube 35 and the blower device, so that the heat in the heating furnace 31 reaches the blower device 36 through the ventilation tube 35 during sample heating, and the device 36 is heated. Is prevented.

When cooling the heating furnace 31, cooling air sent through the ventilation tube 35 by driving the blower device 36 is directly applied to the heating furnace 31 to perform cooling.

Further, the cooling air that has hit the heating furnace 31 passes through a gap between the heating furnace 31 and the radiation shield 33, passes through a discharge port 39 opened upward, and is discharged to the outside through a discharge port 40 of the heat insulating cover. You.

On the other hand, a part of the cooling air from the blower device 36 is supplied from the gap 41 to the radiation shield 33 and the heat insulating cover 34.
And is discharged from the upper exhaust port 40.

Thus, the heating furnace is cooled.

[0010]

However, the blower device 3
Most of the cooling air ejected from 6 goes straight,
The heating furnace 31 and the radiation shield 33 are discharged from the discharge port 39 and the exhaust port 40 to the outside through the gap between the heating furnace 31 and the radiation shield 33 so that the heating furnace 31 and the radiation shield 33 are cooled. Since the amount of cooling air entering between the heat insulating cover 34 and the heat insulating cover 34 is very small, and the direction of the air flow is not determined, the heated air stays.

Further, since the air between the radiation shield 33 and the heat insulating cover 34, which is located in the opposite direction to the ventilation tube 35, hardly moves, most of the heated air stays.

Therefore, there is a problem that it takes a very long time to cool the heating furnace due to the staying air and the residual heat of the heat insulating cover, and it is not possible to quickly perform a temperature drop analysis for lowering the sample temperature.

The present invention has been made in order to solve the above problems, and provides a thermal analyzer capable of improving the flow of air in the apparatus and cooling the heating furnace in a short time. is there.

[0014]

In order to achieve the above object, a thermal analyzer according to the present invention is arranged such that cooling air flows upward from outside a heating furnace in which a sample is placed, for example, from below. And let this air flow out of the outlet provided above the shield into the space between the heat insulating cover and the shield,
During this time, the gas flows downward from above and is discharged from an exhaust port provided below the heat insulating cover. That is, by circulating the refrigerant in a U-shape inside and outside the shield, it is possible to eliminate the stagnation of air in the device and to provide a structure that promotes the cooling effect.

[0015]

According to the thermal analyzer of the present invention, the above-mentioned structure makes it possible to reduce the air stagnating in the apparatus and to efficiently cool the radiation shield, the heat insulating cover and the heating furnace.

In the above configuration, the air flows from the bottom to the top outside the heating furnace and the air flows from the top to the bottom outside the shield. However, the flow may be reversed.

[0017]

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

FIG. 1 is a schematic longitudinal sectional view of a differential thermal analyzer to which the present invention is applied, and FIG. 2 is a bottom view thereof. In addition, FIG.
2, the same parts are given the same numbers, and the arrows in the figure indicate the flow of the cooling air.

1 is a heating furnace, 2 is a heater wire wound around the core of the heating furnace 1, 3 is a radiation shield, 4 is a heat insulating cover, 5 is a ventilation section for introducing cooling air, and 6 is a blower device. , 8 is an air outlet provided in the radiation shield 3, 9 is an exhaust provided in the heat insulating cover 4, S is a sample, R is a reference sample made of an inert substance which does not thermally change in a measurement temperature range, Reference numeral 10 denotes a support for holding a detector D such as a thermocouple.

The ventilation section 5 for introducing the cooling air from the blower device 6 is provided so that the cooling air is guided to the lower side of the heating furnace 1 as much as possible. The exhaust port 9 is provided at the bottom or the bottom of the side surface of the heat insulating cover 4.

The ventilation section 5 is provided with a radiation shield 3 so that the cooling air from the blower device 6 flows in a specific direction without waste.
In addition to being integrated with the cooling air, the part before the intake of the cooling air has a smaller inside diameter.

When performing the temperature rising analysis, the blower device 6 is stopped, the heating furnace 1 is heated by the heater wire 2, and the heat change occurring in the sample S is detected by the detector D between the sample S and the reference sample R. Is detected as the temperature difference.

Generally, thermal analysis is performed in a range from room temperature to about 1500 ° C.

Next, when performing the temperature drop analysis, the current flowing through the heater wire 2 is turned off to drive the blower device 6. The cooling air (outside air) sent from the blower device 6 is:
The cooling is performed by directly hitting the lower part of the heating furnace 1 through the ventilation part 5.

The cooling air hitting the lower part of the heating furnace 1 is
The air blown from the blower unit 6 successively pushes the space between the heating furnace 1 and the side surface of the radiation shield 3 upward, and blows out from the air outlet 8 toward the heat insulating cover 4.

The blown air then flows downward between the side surface of the radiation shield 3 and the side surface of the heat insulating cover 4.
The air is discharged from the air exhaust port 9 to the outside.

As described above, the cooling air from the blower device 6 flows from the upper part to the lower part of the heating furnace 1, the radiation shield 3, and the heat-insulating cover 4 by touching the whole, so that all of them can be cooled. Since there is almost no stagnation of air, the temperature can be analyzed quickly.

In the above embodiment, the ventilation section 5 is provided below the apparatus. However, the ventilation section 5 is provided above, the air discharge port of the radiation shield is provided at the bottom, and the air exhaust port of the heat insulating cover is provided at the top. Is also good. However, in this case, it is necessary to increase the supply output of the cooling air of the blower device as compared with the above-described embodiment.

Further, in FIG. 3, although the cooling air introduction portion from the blower device is different from that of the above-described embodiment, the air exhaust port of the heat insulating cover of this conventional example may be provided at the lower portion.

[0030]

As described above, according to the thermal analysis apparatus of the present invention, the flow of air in the apparatus is improved and stagnation hardly occurs. Etc. can be cooled quickly.

[Brief description of the drawings]

FIG. 1 is a schematic longitudinal sectional view of a thermal analyzer according to one embodiment of the present invention.

FIG. 2 is a bottom view of the thermal analyzer according to one embodiment of the present invention.

FIG. 3 is a schematic longitudinal sectional view of a conventional thermal analyzer.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) G01N 25/00 G01N 25/20

Claims (1)

(57) [Claims] 1. A tubular heating furnace in which a sample is placed, a radiation shield surrounding the outer periphery thereof, a heat insulating cover surrounding the outer periphery of the shield, and a cooling cover penetrating the heat insulating cover and the radiation shield. A blower device for introducing air, wherein an air discharge port from the inside to the outside of the radiation shield and an exhaust port of the heat insulating cover are provided at one upper part and the other at a lower part, so that the refrigerant flows into and out of the radiation shield. A thermal analyzer, wherein the thermal analyzer is circulated in a U-shape.