JP3135081B2 - Furnace unit of differential scanning calorimeter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a differential scanning calorimeter for measuring a temperature difference between a sample and a standard substance and obtaining a change in the amount of heat generated in the sample from the temperature difference.

[0002]

2. Description of the Related Art A differential scanning calorimeter having a furnace unit having a structure as shown in FIG. 6 is conventionally known. In this furnace body unit, a sample chamber R, which is a concave portion having a circular cross section, is formed on the upper part of a substantially cylindrical furnace body 51. A step Q is formed around the entire inner wall substantially at the center of the sample chamber R.
A disc-shaped thin heat-sensitive plate 52 is joined on the stepped portion Q by spot welding, and further pressed and fixed by a ring member 53. The ring member 53 is tightly fitted to the inner wall of the sample chamber R. At the center of the heat-sensitive plate 52, two sample dishes 54, 54 are placed, and a sample 55 to be measured is stored in one of the sample dishes, and a standard substance 56 is stored in the other. .

[0003] The furnace body 51 is heated by a heater wire 57 wound around its outer periphery. The heat of the furnace body 51 is a heat sensitive plate 52.
To the sample 55 and the standard substance 56. Thereby, the temperature of the sample 55 and the standard substance 56 rises. The temperature of the sample 55 and the standard substance 56 is set to a thermocouple 58,5.
The temperature difference is detected by an arithmetic circuit (not shown), and a heat amount change corresponding to the temperature difference is calculated by an arithmetic circuit (not shown).

[0004]

In the above-described conventional differential scanning calorimeter, the heat-sensitive plate 52 is formed in a disk shape, the entire circumference of which is spot-welded to the inner wall of the furnace, and further fixed by the ring member 53. I was For this reason, the assembling work of the furnace body was very difficult. Further, if any failure occurs in the furnace unit, the entire furnace unit including the heat sensitive plate cannot be used. Further, there is a problem that the joining condition of the spot welding tends to vary, and as a result, the temperature of the heat-sensitive plate does not rise uniformly.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional differential scanning calorimeter, and is easy to assemble, and can be replaced for each part. An object of the present invention is to provide a furnace unit of a differential scanning calorimeter capable of raising the temperature.

[0006]

In order to achieve the above object, a furnace unit of a differential scanning calorimeter according to the present invention comprises a furnace body to be heated, and a furnace body disposed in the furnace body, and A heat-sensitive plate heated by the heat of the sample, and a furnace unit used for a differential scanning calorimeter for measuring the temperature of a sample and a standard substance placed on the heat-sensitive plate. The heat-sensitive plate has a fixed portion fixed to the bottom surface of the sample chamber and a bent portion formed from the fixed portion, on which the sample and the standard substance are placed. A sample mounting portion, and a heat equalizing block that fills the space is provided in a space between the heat-sensitive plate and the inner peripheral wall of the sample chamber, and a fixing portion of the heat-sensitive plate is provided on a bottom surface of the sample chamber. It is characterized by being screwed in surface contact.

[0007]

The heat sensitive plate can be easily assembled to the furnace body by screwing. By releasing the screws, the heat sensitive plate can be easily removed from the furnace body. If a fault occurs in either the furnace body or the heat sensitive plate, only the faulty one can be replaced with a new one, which is very economical. Variations do not occur in the bonding condition between the heat-sensitive plate and the furnace body, and the temperature of the heat-sensitive plate rises uniformly.

[0008]

FIG. 2 shows an example of a differential scanning calorimeter using a furnace unit according to the present invention. The differential scanning calorimeter includes a disk-shaped base 10 placed on a table (not shown), a first circular heat insulating plate 12 installed above the base 10 by a support 11, and a support 13. A second heat insulating plate 14 disposed above the first heat insulating plate 12 and a third circular heat insulating plate 16 disposed above the second heat insulating plate 14 by the support 15. Each strut 11, 13,
15 are shown one by one, but in reality, the number of the heat insulating plates 12, 14, 16 can be stably supported, for example, three.

The furnace unit 3 is mounted on the third heat insulating plate 16 at the uppermost position, and the furnace unit 3 is attached to the third heat insulating plate 16 by fastening means such as screws (not shown) as necessary. Fixed. As shown in FIG. 1, the furnace unit 3 has a cylindrical furnace body 1 made of silver. A heater wire 7 is wound around the outer periphery of the furnace body 1, and a silver cylindrical cover 17 is mounted outside the heater wire 7. The cover 17 is joined to the outer peripheral surface of the furnace body 1 and is integral with the furnace body 1, and its lower end portion projects below the furnace body 1. The projecting portion is fixed to the third heat insulating plate 16.

A sample chamber R having a circular cross section is formed in the upper part of the furnace body 1. Are fixed by two screws 18. The heat-sensitive plate 2 includes two fixing portions 2a formed by bending a single thin plate, and a sample mounting portion 2b formed between the fixing portions. As described above, in the present embodiment, the furnace body 1 has excellent heat conduction,
It is formed of a material softer than the heat-sensitive plate 2.

On the sample mounting portion 2b of the heat sensitive plate 2, two sample dishes 4, 4 are placed, one of which is a sample 5 to be measured, and the other is a standard material 6 Is housed. A material that is thermally stable, that is, hardly changes in characteristics even when the temperature changes, is selected as the standard material 6. During the measurement, the upper part of the sample 5 and the standard substance 6 is shielded from the outside by a circular sample lid 19 as shown in FIG.

Thermocouples 8 and 9 are joined to the lower surface of the heat sensitive plate 2 where the sample 5 and the standard material 6 are placed by spot welding or the like. The thermocouple 8 on the sample side and the thermocouple 9 on the standard material side are each composed of two wires.

In FIG. 2, the base 10 and the first heat insulating plate 12
The cylindrical heat insulating tube 20 is arranged between the two. Then, the heat insulating lid 21 is placed on the first heat insulating plate 12. Further, another cylindrical heat insulating pipe 2 is placed on the second heat insulating plate 14.
2 and another heat insulating lid 23 inside the heat insulating pipe 22.
Is arranged. An outer cover having a lid 24 a is fitted on the outer peripheral surface of the base 10, and the above-described components are hermetically stored in the outer cover 24.
The furnace body unit 3 is provided by the base 10 and the exterior cover 24.
Is constituted so as to surround the whole of the furnace.

The thermocouples 8 and 9 joined to the heat-sensitive plate 2 hang down through a through hole 25 provided at the center of the furnace body 1 and further pass through a through hole 26 provided at the center of the base 10 to form the furnace body. The heat is guided to the outside of the casing, and is connected to the calorific value calculation circuit 27. On the right side of the center of the furnace body 1 is another thermocouple 28
Are connected. The thermocouple 28 is guided to the outside of the furnace casing and connected to a heater temperature control circuit 29. The heater wire 7 extends below the furnace body unit 3 at the right end of the furnace body unit 3 and is guided outside the furnace body casing to supply a heater current supply circuit 30.
It is connected to the.

The sample chamber R inside the furnace body 1 shown in FIG.
In some cases, a vacuum state is set. In addition, an inert gas may flow into the sample chamber R in some cases. Although not specifically shown in FIGS. 1 and 2, the differential scanning calorimeter includes a vacuum suction device for evacuating the sample chamber R and a sample chamber R.
In some cases, a gas supply system for supplying gas into the inside is provided. In consideration of such a case, a fitting for air suction and a fitting for gas supply may be provided at an appropriate position of the base 10.

The operation of the differential scanning calorimeter having the above configuration will be described below. In FIG. 2, a current is supplied from the heater current supply circuit 30 to the heater wire 7, and the heater wire 7 in a portion wound around the furnace body 1 generates heat to heat the furnace body 1. The heat of the furnace body 1 is transmitted to the sample 5 and the standard material 6 through the heat sensitive plate 2, and heats them to increase the temperature.

The temperature of the furnace body 1 is detected as a thermoelectromotive force by a thermocouple 28, and an electric signal thereof is sent to a heater temperature control circuit 29. The control circuit 29 controls the heater current supply circuit 30 based on the sent temperature signal. Thereby, the heater wire 7 wound around the furnace body 1 generates heat at an accurate temperature according to a predetermined program.

Since the reference material 6 is thermally stable, no physical change occurs when the temperature is increased. On the other hand, the sample 5 undergoes a physical change, for example, melting and evaporation, due to an increase in temperature according to its own characteristics. When this change occurs, a temperature change occurs in the sample 5, and as a result, a temperature difference occurs between the sample 5 and the standard substance 6. The temperatures of both are detected by the thermocouples 8 and 9, and the detection results are sent to the calorific value calculation circuit 27 as a temperature signal.
Upon receiving the temperature signal, the calorific value calculation circuit 27 calculates the temperature difference between the sample 5 and the standard substance 6, and calculates the change in the calorific value generated in the sample 5 from the temperature difference. The calculated change in calorific value is recorded on a recorder (not shown).

In the differential scanning calorimeter, the first to
The third heat insulating plates 12, 14, 16 prevent heat generated in the furnace unit 3 from being transmitted to the base 10. Further, these heat insulating plates also function as furnace body support means for supporting the furnace body unit 3 on the base 10.

In the above differential scanning calorimeter, the heat sensitive plate 2 is fixed to the furnace body 1 by screws 18 as shown in FIG. Therefore, assembling of the furnace body unit 3 is very easy as compared with the case where the entire periphery of the heat sensitive plate 52 is spot-welded to the furnace body 51 as in the conventional apparatus shown in FIG.
Further, when either the heat sensitive plate 2 or the furnace body 1 is damaged, the two can be easily separated by releasing the screw tightening, and only the damaged one can be replaced with a new one.

Incidentally, the furnace body 1 and the heat sensitive plate 2 are often made of materials having different coefficients of thermal expansion. In this case, when they are heated by the heater wire 7,
There is a difference in elongation between the furnace body 1 and the heat sensitive plate 2 due to thermal expansion. In the present embodiment, since the heat-sensitive plate 2 is bent into a bent shape to form the fixed portion 2a and the sample mounting portion 2b, the heat-sensitive plate 2 is elastically deformed even when the above-described elongation error occurs. This can prevent the furnace body 1 and the heat sensitive plate 2 from being damaged.

As shown in FIG. 1, two substantially semicircular heat equalizing blocks 31 are provided on both sides of the heat sensitive plate 2 between the heat sensitive plate 2 and the inner wall of the sample chamber R. As shown in FIG. 3, each of the heat equalizing blocks 31
The screws 32 are fixed to the bottom surface of the sample chamber R in the furnace body 1 and are arranged so as to completely fill the space between the heat-sensitive plate 2 and the inner wall of the sample chamber R. Soaking block 3
Numeral 1 is made of a material having a high thermal conductivity, for example, silver, and heats the heat-sensitive plate 2 so that the entire heat-sensitive plate 2 is uniformly heated.

FIGS. 4 and 5 show modified examples of the heat sensitive plate 2. The heat-sensitive plate 42 shown in FIG. 4 is constituted by a fixed portion 42a and a sample mounting portion 42b, similarly to the heat-sensitive plate 2 shown in FIG. Are formed. Generally, in a differential scanning calorimeter, a temperature difference between a sample 5 and a standard substance 6 is detected. Therefore, when a temperature difference occurs between the two, the temperature difference must be accurately detected. As shown in FIG. 1, when the shape of the sample mounting portion 2a is formed in a single flat plate shape, heat is freely transferred between the sample 5 and the standard material 6, and the minute It may not be possible to detect an excessive temperature difference. On the other hand, in the heat-sensitive plate 42 shown in FIG. 4, the heat transfer generated between the sample 5 and the standard substance 6 is suppressed by the upright portion 43, and as a result, even a minute temperature difference can be accurately detected.

In the heat-sensitive plate 62 shown in FIG. 5, cutouts 63 are provided on both sides of the center of the sample mounting portion 62b, and the cross-sectional area of the heat-sensitive plate at the center is reduced. With this configuration, as in the case of the heat-sensitive plate 42 shown in FIG. 4, the heat transfer between the sample 5 and the standard material 6 is suppressed, and the minute temperature difference generated between the two can be accurately determined. Is detected.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited to the embodiments. For example, in the embodiment shown in FIG. 1, the heat-sensitive plate 2 is formed in a rectangular shape when viewed from above, but the heat-sensitive plate 2 may be formed in any other shape,
For example, a circular shape or an elliptical shape is also possible. The number of screws for fixing the heat sensitive plate to the furnace body is not limited to two, but may be larger. Further, the positions where these screws are provided are not limited to specific positions.

[0026]

According to the present invention, since the heat sensitive plate is fixed to the furnace body by screwing, the heat sensitive plate and the furnace body can be easily assembled and separated easily. Furthermore, joining is more reliable than when joining the heat sensitive plate and the furnace body by spot welding, and as a result, the heat sensitive plate can be uniformly heated.

[Brief description of the drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of a furnace unit of a differential scanning calorimeter according to the present invention.

FIG. 2 is a side sectional view showing an entire example of a differential scanning calorimeter using the furnace unit.

FIG. 3 is a plan view of the furnace body according to an arrow III in FIG.

FIG. 4 is a perspective view showing a modified example of the heat sensitive plate.

FIG. 5 is a perspective view showing another modified example of the heat sensitive plate.

FIG. 6 is a sectional perspective view showing an example of a conventional furnace unit.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Furnace body 2, 42, 62 Heat sensitive plate 2a, 42a, 62a Fixed part 2b, 42b, 62b Sample mounting part 5 Sample 6 Standard material 18 Screw 31 Heat equalizing block

Claims (3)

(57) [Claims] 1. A and the furnace body to be heated, has a thermal plate that is heated is disposed in the furnace body by the heat from the furnace body, samples and standards were placed on the thermal plate on In a furnace body unit used for a differential scanning calorimeter for measuring a temperature of a substance, the furnace body is a space having a circular cross section that accommodates the heat sensitive plate.
A fixing portion having a sample chamber, wherein the heat-sensitive plate is fixed to a bottom surface of the sample chamber;
And the sample and the front formed by being bent from the fixing portion.
A sample mounting portion on which the standard material is mounted, and a space between the heat sensitive plate and an inner peripheral wall of the sample chamber is provided with the empty space.
A heat equalizing block is provided to fill the gap, and the fixing part of the heat sensitive plate is in surface contact with the bottom surface of the sample chamber.
A furnace body unit for a differential scanning calorimeter, which is screwed in a state . 2. The heat equalizing block according to claim 1,
A furnace unit for a differential scanning calorimeter, which is screwed to a bottom surface of the sample chamber . 3. The sensor according to claim 1, wherein
The fixed part of the hot plate and the sample mounting part bend a square plate
The soaking block is approximately semicircular
A furnace unit for a differential scanning calorimeter, which is formed in a shape .