JP2573010Y2 - Thermal analyzer - Google Patents

Description

[Detailed description of the invention]

[0001]

In this invention, a sample container is supported at an upper end of a vertically extending sample holder, a balance is arranged at a lower end of the sample holder, and an atmosphere gas is supplied from above and a curtain gas is supplied from below. To a thermal analyzer as described above. Typically, it relates to a thermogravimetric analyzer (TG), a thermogravimetric / differential thermal analyzer (TG-DTA), a thermomechanical analyzer (TMA), and the like.

[0002]

2. Description of the Related Art FIG. 3 is a front sectional view of a conventional TG-DTA apparatus for performing a thermal analysis of a sample in a steam gas atmosphere.
The steam gas 10 is supplied to the inside of the protection tube 12 from above. On the other hand, the curtain gas 14 is supplied to the inside of the protection tube 12 from below through the through hole of the sleeve 16. These water vapor gas and curtain gas are discharged in the direction of arrow 18 through the space between the protective tube 12 and the sleeve 16. The sample holder 20 passes through the inside of the through hole of the sleeve 16, and the curtain gas passes around the sample holder 20 and blows out from the upper end of the sleeve 16 into the internal space of the protective tube 12.

A sample container 22 is provided at an upper end of a sample holder 20.
The lower end is supported by a balance 24. Sample container 2
2 is surrounded by a protective tube 12, and the periphery of the protective tube 12 is surrounded by a heating furnace 26.

[0004]

SUMMARY OF THE INVENTION In the conventional apparatus shown in FIG. 3, when a high-concentration steam gas is used as an atmosphere gas,
The following problems arise. First, dew condensation occurs on the sample holder 20. Since the upper part of the protective tube 12 is heated by the heating furnace 26, no dew condensation occurs near the sample container 22 in the sample holder 20. However, since the lower portion of the protection tube 12 is cooled by the air-cooling fins 28, there is a possibility that dew condensation may occur at the lower portion of the sample holder 20. Sleeve 1
6 is protected by the curtain gas and does not come in contact with the steam gas, but the range A from the lower end of the heating furnace 26 to the upper end of the sleeve 16 is protected by the curtain gas.
In this case (approximately 45 mm in this example), the water vapor gas comes into contact with the relatively low-temperature sample holder portion, and dew condensation easily occurs. If condensation occurs on the sample holder 20, an error occurs in the measurement result of the balance 24.

[0005] If the flow velocity of the curtain gas blown from the upper end of the sleeve 16 is made very large, the sample holder 20 is protected to a considerable extent by the curtain gas,
Dew condensation is less likely to occur. However, if the flow velocity of the curtain gas is too large, disturbance will be given to the sample holder 20 and the sample container 22, and there is a possibility that an error may occur in the measurement result by the balance 24.

If the lower portion of the protective tube 12 is heated without cooling, the temperature of the lower portion of the sample holder 20 does not become low and no condensation occurs. However, in this case, the temperature in the vicinity of the balance 24 rises, and a drift occurs in the measurement result of the balance 24, and the material of the components of the balance 24 is restricted.
For high precision measurements, the balance needs to be maintained at a relatively low and constant temperature.

When the upper end of the sleeve 16 is closer to the lower end of the heating furnace 26, the above-mentioned range A is reduced, and the sample holder portion exposed from the sleeve is only a relatively high temperature portion, and no dew condensation occurs. However, the sleeve 16 approaches the heating furnace 26 and is heated to a high temperature. When the metal sleeve 16 having a relatively large heat capacity and a large heat conductivity is heated, the metal sleeve 16 is transmitted through the sleeve 16 and is moved to the balance 2.
The temperature of No. 4 tends to rise, which is still a problem. Further, when the upper end of the sleeve 16 is brought closer to the heating furnace 26, a problem of heat resistance of the sleeve 16 occurs.

In the above-mentioned conventional example, the case where steam gas is used as the atmosphere gas is described. However, even when other atmosphere gas, for example, an active gas or a corrosive gas is used, the sample holder should be a curtain gas as much as possible. It is desirable to protect it.

The present invention has been made to solve the above-mentioned problems, and an object thereof is to protect a sample holder near a heating furnace with a curtain gas.

[0010]

Means and Action for Solving the Problems The first device is as follows.
The space above the upper end of the sleeve is protected by an extension tube separate from the sleeve. That is, a sample container,
An elongated sample holder that supports the sample container and extends vertically, a balance arranged at the lower end of the sample holder, a protection tube surrounding the sample container, and a heating furnace surrounding the protection tube are provided with an atmosphere inside the protection tube. In a thermal analyzer in which a gas is supplied from above and a curtain gas is supplied from below into a protective tube, a sample holder passes through a through hole formed in a sleeve, and a curtain gas flows through the inside of this through hole. The space passing upward and above the upper end of the sleeve is separated from the inner space of the protective tube by an extension tube separate from the sleeve, and curtain gas exits from the outlet at the upper end of the extension tube into the inner space of the protective tube. It is something to go.

Since the space above the sleeve is separated from the inner space of the protective tube by the extension tube, the sample holder inside the extension tube is protected by the curtain gas and does not come into contact with the atmosphere gas. Further, since the sleeve itself does not approach the heating furnace, there is no danger of the sleeve being heated.

This invention is designed to avoid contact of the atmosphere gas with the relatively low-temperature sample holder as much as possible. And the like.

In a second aspect of the present invention, the above-mentioned extension tube is fitted around the outer periphery of the sleeve, and the cross-sectional area of the outlet at the upper end of the extension tube is made smaller than that of the sleeve. If the extension tube is fitted on the outer periphery of the sleeve, the conventional sleeve can be used as it is.Therefore, the same case is required for the special atmosphere gas that requires the extension tube and the case that does not require the extension tube. The sleeve can also be used. However, since the cross-sectional area of the outlet at the upper end of the extension pipe cannot be so large, the outlet at the upper end of the extension pipe is narrowed. If the cross-sectional area of the outlet of the extension pipe is increased, the flow velocity of the curtain gas flowing from the outlet to the inner space of the protection pipe decreases, and there is a possibility that atmospheric gas may enter the inside of the extension pipe from the outlet of the extension pipe.

In a third aspect of the present invention, the cross-sectional area of the outlet of the above-mentioned extension tube is set to 1 cm 2 or less. Although the actual flow rate of the curtain gas is 30 to 100 cc / min, in order to secure a certain flow rate of the curtain gas at the outlet of the extension pipe with respect to this flow rate, the cross-sectional area of the outlet at the upper end of the extension pipe needs to be Therefore, it is preferable that the width be 1 cm 2 or less.

In a fourth aspect of the present invention, the above-mentioned atmosphere gas is changed to steam gas. When water vapor gas is used as the atmosphere gas, a problem of dew condensation on the sample holder occurs. However, the present invention is effective in preventing the dew condensation.

According to a fifth aspect of the present invention, a curtain gas supply passage for supplying curtain gas to the through hole and a space between the protection tube and the extension tube communicate with the outside of the sleeve. The gas discharge passage and the gas discharge passage are integrally formed. When steam gas is used as the atmosphere gas, water condensed with the steam gas is also discharged from the passage for communicating the space between the protection tube and the extension tube to the outside.

In the sixth invention, the first invention is limited to a thermal analyzer capable of performing thermogravimetry and differential thermal analysis.

According to a seventh aspect of the present invention, the position of the outlet through which the curtain gas exits into the inner space of the protective tube is set at a distance of 15 mm from the lower end of the heating furnace.
mm above the lower position.
That is, a sample container, an elongated sample holder that supports the sample container and extends in the vertical direction, a balance arranged at the lower end of the sample holder, a protective tube surrounding the sample container, and a heating furnace surrounding the protective tube, In a thermal analyzer in which an atmosphere gas is supplied from above into a protective tube and a curtain gas is supplied from below from inside a protective tube, a sample holder passes through a through hole formed in a sleeve, and the through hole is provided. The position of the outlet through which the curtain gas passes upwards and the curtain gas exits into the inner space of the protective tube is located above the position 15 mm below the lower end of the heating furnace. .

The seventh invention differs from the first invention in that the seventh invention does not require a separate extension tube as an essential component, while the position of the curtain gas outlet is changed. This is to limit the heating furnace to a position above a position 15 mm below the lower end of the heating furnace. By bringing the curtain gas outlet close to the heating furnace in this way, the relatively low temperature sample holder portion is prevented from contacting the ambient gas. However, if the curtain gas outlet is brought closer to the heating furnace by simply extending the metal sleeve having the conventional structure upward, the sleeve is heated and various problems occur. In order to achieve this idea by extending the sleeve upward, the conventional sleeve is formed of a material having a low thermal conductivity, a material having a high heat resistance, or a heat capacity is reduced. Need to be improved. Of course, the use of an extension tube separate from the sleeve could also be a means to accomplish this invention.

In an eighth aspect, in the seventh aspect, the atmospheric gas is changed to a steam gas.

[0021]

FIG. 1 is a front sectional view of an embodiment of the present invention. In this embodiment, the present invention is applied to a TG-DTA device. At the upper end of two vertically elongated sample holders 30, there are two sample containers 32 each containing a sample and a reference substance, and the lower end of the sample holder 30 is supported by a balance. The sample container 32 is surrounded by a protective tube 35 made of ceramics or glass, and the upper periphery of the protective tube 35 is surrounded by a heating furnace 36. The heating furnace 36 is an electric furnace, and a heater wire 37 for heating is wound around the outer periphery of the heating furnace 36.

The sample holder 30 passes through a through hole 39 formed in the sleeve 38. In the sleeve 38,
The curtain gas supply passage 40 and the gas discharge passage 42 are integrally formed. An extension pipe 4 is provided around the outer periphery of the sleeve 38.
4 is fitted, and the upper end of the extension tube 44 is
Extends to the vicinity of the lower end.

The steam gas 46 is supplied to the inside of the protection tube 35 from above. On the other hand, the curtain gas 48 composed of dry nitrogen gas or dry air is supplied to the curtain gas supply passage 40.
, Through the through hole 39, into the internal space of the extension tube 44, and further supplied from the outlet 50 at the upper end of the extension tube 44 to the internal space of the protection tube 35.

The steam gas, the curtain gas, and the water condensed with the steam gas are supplied to the protection pipe 35 and the extension pipe 44.
And enters the gas discharge passage 42 and is discharged in the direction of arrow 52.

The air-cooled fins 5
4 is attached to cool the lower part of the protection tube 35. The air cooling fins 54 are cooled by a fan (not shown). The base 39 below the sleeve 38 is also water-cooled. By these cooling mechanisms, the extension pipe 44
And the sleeve 38 are also cooled. Therefore,
Even when the sample is heated by the heating furnace 36, the balance 34 maintains a relatively low constant temperature.

The distance L from the lower end of the heating furnace 36 to the upper end of the extension tube 44 is 10 mm in this embodiment. If the distance L is too large, the relatively low temperature of the sample holder portion comes into contact with the steam gas, and dew condensation easily occurs on the sample holder 30. This distance L is preferably within 15 mm. The upper end of the extension tube 44 may be located above the lower end of the heating furnace 36, but from the viewpoint of preventing dew condensation, there is not much need to do so.

FIG. 2 is a perspective view of the extension tube 44. The upper end of the extension tube 44 is narrowed, and the outlet 50 is 4 mm ×
It is a 20 mm long round shape. The cross-sectional area of the outlet 50 is about 0.8 square cm. On the other hand, the outer diameter near the upper end of the sleeve 38 in FIG. 1 is 20 mm, and the cross-sectional area of the sleeve 38 in this portion is about 3.1 square cm. Therefore,
The cross-sectional area of the outlet 50 of the extension tube 44 is considerably smaller than the cross-sectional area of the sleeve portion in which the extension tube 44 is fitted. In this embodiment, the flow rate of the curtain gas is set to 50 cc /
min, but at this time the outlet 50 of the extension pipe 44
The average flow velocity of the curtain gas at about 63 cm / min
Becomes With such a flow rate, there is no possibility that the steam gas enters the inside of the extension tube 44 from the outlet 50 of the extension tube 44. Practical flow rate of curtain gas is 30-100cc
/ Min, and in order to secure a certain flow rate of the curtain gas at the outlet 50 of the extension pipe 44 at this time, it is preferable that the cross-sectional area of the outlet 50 be 1 cm 2 or less. The flow rate of the curtain gas at which the steam gas does not enter the inside of the extension pipe is considered to depend on the supply flow rate of the steam gas and the pressure of the inner space of the protection pipe. The preferred values are approximate.

As a material of the extension tube 44, platinum or ceramics (alumina, etc.) can be used for high-temperature analysis, and aluminum may be used for low-temperature analysis at 600 ° C. or lower. The thickness of the extension tube 44 is preferably reduced in order to reduce heat conduction. Since the extension tube 44 can be detached from the sleeve 38, the use or non-use of the extension tube 44 can be selected depending on the atmospheric gas, and the extension tube 44 can be replaced depending on the analysis temperature.
The shape of the outlet 50 of the extension tube 44 may be other than a long circle, and may be, for example, two circular holes.

Next, the operation of the TG-DTA device will be described. In FIG. 1, a sample and a reference substance are put in a sample container 32, a steam gas 46 is introduced from above, and a curtain gas 48 is introduced from below. The sample and the reference substance are heated at a desired temperature curve by using the heating furnace 36, and the change in weight of the sample in steam gas and the endothermic heat are measured.

The curtain gas 48 is supplied to the outlet 50 of the extension pipe 44.
From the protection tube 35 to the internal space. Therefore, the sample holder inside the extension tube 44 does not come into contact with the steam gas. Since the curtain gas exits the outlet 50 at a certain flow rate as described above, the steam gas does not enter the inside of the extension pipe 44. The curtain gas and the steam gas finally pass between the lower inner wall of the protection tube 35 and the outer wall of the extension tube 44, and are discharged outside through the gas discharge passage 42 of the sleeve 38.

Since the lower portion of the protection tube 35 is cooled by the air-cooled fins 54, the steam gas is easily condensed on the inner wall of the lower portion of the protection tube 35, and the condensed water is also discharged from the gas discharge passage. Due to the condensation of the steam gas, the pressure in the space between the inner wall of the protection tube 35 and the outer wall of the extension tube 44 decreases. Thereby, the gas existing in the internal space above the protection tube 35 is pulled downward with a low pressure, and the gas discharging action is promoted. That is, the atmosphere around the sample is always covered with fresh steam gas, and the reaction between the sample and the steam gas is correctly performed. Further, there is no possibility that the reaction product gas stays near the sample.

This embodiment is particularly effective when a high-concentration steam gas (for example, a room temperature saturated vapor pressure of 600 Torr or more) is introduced.

This invention is applicable not only to the above-mentioned TG-DTA device but also to other thermal analyzers such as a TG device and a TMA device.

[0034]

According to the thermal analyzer of the present invention, a relatively low temperature portion (a portion far from the heating furnace) of the sample holder can be protected by the curtain gas. When water vapor gas is used as the atmospheric gas, dew condensation on the sample holder can be prevented, and a measurement error of the balance due to dew condensation can be reduced.

[Brief description of the drawings]

FIG. 1 is a front sectional view of one embodiment of the present invention.

FIG. 2 is a perspective view of an extension tube.

FIG. 3 is a front sectional view of a conventional device.

[Description of Signs] 30 Sample holder 32 Sample container 34 Balance 35 Protective tube 36 Heating furnace 38 Sleeve 39 Through hole 40 Curtain gas supply passage 42 Gas exhaust passage 44 Extension tube 46 Water vapor gas 48 Curtain gas 50 Outlet 54 Air cooling fin

Claims (8)

(57) [Scope of request for utility model registration] 1. A sample container, an elongated sample holder supporting the sample container and extending vertically, a balance disposed at a lower end of the sample holder, a protection tube surrounding the sample container, and a heating furnace surrounding the protection tube. In the thermal analyzer, which supplies the atmosphere gas into the inside of the protection tube from above and supplies the curtain gas into the inside of the protection tube from below, the sample holder passes through the through hole formed in the sleeve, Curtain gas passes upward through the inside of this through hole,
The space above the upper end of the sleeve is separated from the inner space of the protection tube by an extension tube separate from the sleeve, and curtain gas exits from the outlet at the upper end of the extension tube to the inner space of the protection tube. Analysis equipment. 2. The thermal analysis according to claim 1, wherein the extension tube is fitted around the outer periphery of the sleeve, and a cross-sectional area of an outlet at an upper end of the extension tube is smaller than a cross-sectional area of the sleeve. apparatus. 3. The thermal analyzer according to claim 2, wherein a cross-sectional area of an outlet at an upper end of the extension tube is 1 cm 2 or less. 4. The thermal analyzer according to claim 1, wherein the atmosphere gas is a steam gas. 5. The sleeve includes a curtain gas supply passage for supplying curtain gas to the through hole, and a gas discharge passage for communicating a space between the protection tube and the extension tube to the outside. The thermal analyzer according to claim 1, wherein the thermal analyzer is provided. 6. The thermal analyzer according to claim 1, wherein the thermal analyzer is capable of performing thermogravimetry and differential thermal analysis. 7. A sample container, an elongated sample holder supporting the sample container and extending vertically, a balance disposed at a lower end of the sample holder, a protection tube surrounding the sample container, and a heating furnace surrounding the protection tube. In the thermal analyzer, which supplies the atmosphere gas into the inside of the protection tube from above and supplies the curtain gas into the inside of the protection tube from below, the sample holder passes through the through hole formed in the sleeve, Curtain gas passes upward through the inside of this through hole,
A thermal analyzer wherein the position of an outlet through which the curtain gas exits into the inner space of the protective tube is above a position 15 mm below the lower end of the heating furnace. 8. The thermal analyzer according to claim 7, wherein the atmosphere gas is a steam gas.