JPH09101274A - Thermal analyzer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To sufficiently attenuate temperature fluctuation in a heating furnace caused by temperature control noise and, at the same time, to improve the heat radiating efficiency of the furnace by forming through holes in the body of the furnace. SOLUTION: A plurality of through holes 1b is formed in the body 1 of a heating furnace so that the temperature fluctuation caused by temperature control noise can be prevented from being transmitted to the sample housing section 1a of the main body 1 by the increased heat resistance of such a fluid as an inert gas, etc., which is supplied to the periphery of the section 1a when the density of the fluid increases. When a lid body 5 is put on the body 1, in addition, the upper openings of the holes 1b are blocked with the jaw section 5b of the lid body 5.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a thermal analyzer for performing differential scanning calorimetry (DSC) and the like.

[0002]

2. Description of the Related Art Thermal analysis is widely used as one of the test methods for obtaining the thermal properties of various materials and for investigating the thermal stability of various inorganic and organic compounds. The most frequently used thermal analysis is differential scanning calorimetry. Differential scanning calorimetry measures the temperature difference between a sample to be measured and a thermally inactive reference substance, and is a unit that is supplied extra or less to the sample based on the signal indicating this temperature difference. The enthalpy change associated with the transition and chemical reaction of this sample is investigated by obtaining the thermal energy per unit time.

FIG. 5 shows the configuration of a conventional thermal analysis device for performing the differential scanning calorimetry. The heating furnace body 1 is made of a material having a high thermal conductivity such as silver in order to make the temperature distribution in the furnace uniform. The heating furnace body 1 is formed with a concave sample storage portion 1a having an opening on the upper surface.
The sensor unit 2 is housed in a. The sensor unit 2 includes a disk-shaped plate 2a for mounting the sample container 3 and the reference material container 4, and a thermocouple bonded to the back surfaces of the mounting portions of the sample container 3 and the reference material container 4 on the plate 2a. And the lower end of each wire 2b is led out to the back surface side through a minute hole of the heating furnace main body 1. Therefore, the temperature T _s of the sample 8 in the sample container 3 is detected by detecting the electromotive force in the wire 2b of these thermocouples.
The temperature difference ΔT between the temperature T _s and the temperature of the reference substance 9 in the reference substance container 4 can be measured. A lid 5 made of a material having a high thermal conductivity similar to that of the heating furnace body 1 is provided in the upper opening of the sample storage portion 1a.
Is fitted to close the inside of the sample storage portion 1a in which the sensor unit 2 is stored.

A heater wire 6 is wound around the outer peripheral side surface of the heating furnace body 1. Further, a temperature sensor 7 by a thermocouple is embedded slightly inside the outer peripheral side surface of the heating furnace body 1 so that the temperature T _f of the heating furnace body 1 heated by the heater wire 6 can be detected. There is. Then, by feeding back the temperature T _f detected by the temperature sensor 7 to the controller of the heater wire 6,
The temperature of the heating furnace body 1 can be precisely controlled.

[0005]

The controller for the heater wire 6 controls the temperature of the heating furnace body 1 according to the temperature program based on the PID control. By the way, in this temperature control system, since the heating furnace body 1 usually has a large heat capacity, a time delay element is added until the heat generation of the heater wire 6 is transmitted to the heating furnace body 1 and detected by the temperature sensor 7. By embedding the temperature sensor 7 at a position closest to the heater wire 6 of the heating furnace body 1, the influence of this time delay element is minimized. However, since this time delay element cannot be completely removed, the actual temperature T _f of the heating furnace main body 1 does not accurately follow the set temperature of the temperature program, but the amplitude as shown in FIG. It follows that a change in n _c occurs, and such a temperature change becomes temperature control noise. When the temperature fluctuation due to the temperature control noise is transmitted to the sample 8 and the like, it is a slight temperature fluctuation that can be ignored in normal temperature control, but it is necessary to measure a minute temperature difference or the like precisely. In the case of differential scanning calorimetry or the like, there is a possibility that the measurement result may be adversely affected.

Therefore, in the conventional thermal analysis apparatus, the heating furnace body 1 is enlarged to some extent to increase the heat capacity, so that the temperature _Tf causes a temperature fluctuation of the amplitude n _c due to temperature control noise, as shown in FIG. Even if it appears, the furnace body 1
This temperature fluctuation is attenuated by its own damping effect so that only the temperature fluctuation having an extremely small amplitude n _d appears in the temperature T _{s of the} sample 8 to reduce the influence of the temperature control noise. However, since the heating furnace body 1 is made of a material having a high thermal conductivity such as silver and has a low damping effect, the amplitude n _{d of the} temperature fluctuation appearing in the temperature T _{s of the} sample 8 is sufficiently attenuated in the conventional thermal analysis device. However, there is a problem in that it is impossible to completely eliminate the possibility that the temperature control noise adversely affects the measurement.

If the heater wire 6 is wound around the outer peripheral surface of the heating furnace main body 1 through a heat resistant heat insulating material such as cement or ceramic fiber, the damping effect of these heat insulating materials having low thermal conductivity is achieved. it can by sufficiently attenuate the amplitude n _d of the temperature T _s of the sample 8 shown in FIG. 7, to solve the above problems. However, since such a heat insulating material has a large thermal resistance and significantly impairs the trackability of the temperature T _s of the sample 8 to the temperature T _f of the heating furnace body 1, the heat capacity is large, and therefore, the heating furnace body after the measurement is completed. It takes a long time to cool 1. Moreover, even if an attempt is made to cool the heating furnace main body 1 by air, the heat radiation efficiency deteriorates because the outer peripheral side surface is covered with the heat insulating material. Therefore, with such a heat insulating material,
When the measurement is repeated using the same thermal analysis device, it takes time to cool the heating furnace body 1 and the work efficiency deteriorates.

The present invention has been made in view of the above circumstances, and it is possible to sufficiently attenuate the temperature fluctuation due to temperature control noise and improve the heat dissipation efficiency by forming a through hole in the heating furnace main body. It is an object of the present invention to provide a thermal analysis device capable of performing the above.

[0009]

That is, in order to solve the above-mentioned problems, the present invention is provided with a sample storage portion for storing a sample inside a heating furnace main body, and is provided around the heating furnace main body. In the thermal analyzer provided with the heating means, a through hole is formed around the sample storage portion in the heating furnace body.

According to the means of (1), the through hole is arranged in the conduction path when the heat from the heating means is conducted through the heating furnace main body and is transmitted to the sample storage portion. Here, the heating furnace body is generally made of a material having a sufficiently high thermal conductivity such as silver, but the through hole is filled with a fluid such as an inert gas filled around the heating furnace body. Therefore, the thermal conductivity of this through hole is extremely low. Therefore, the heat from the heating means is damped by the thermal resistance of the through hole, so that the temperature fluctuation due to the temperature control noise can be prevented from being transmitted to the sample.

If the heating furnace main body has the same size as the one without through holes, the heat capacity is small, so that the amount of heat to be radiated is small, and the heating furnace can be cooled in a short time after the measurement. Further, if the heat capacity is the same, since the size is larger and the surface area is larger than that without the through hole, the heat radiation amount is also large, and in this case also, it becomes possible to cool in a short time after the measurement. Moreover, the fluid that naturally convects in the through-hole or the fluid that is forcedly fed can accelerate the heat dissipation of the heating furnace body and cool it further rapidly.

Further, the above-mentioned through holes are a plurality of holes penetrating through the heating furnace main body in the vertical direction, and are arranged so as to surround the periphery of the sample storage portion.

According to the means of (1), since the plurality of through holes are arranged so as to surround the periphery of the sample storage portion, the effect of damping the heat from the heating means can be made uniform and stable. Moreover, since these through holes penetrate the heating furnace body in the vertical direction, the fluid can easily naturally convect during cooling after the measurement, and the heat dissipation efficiency can be improved.

Further, there is provided a lid body which is attached to the heating furnace body and closes the upper opening of the sample storage section, and a peripheral through-hole at the time of attachment to the heating furnace body at the peripheral portion of the lid body. A collar portion for closing the upper end opening of the is formed.

According to the above means, when the lid is mounted at the time of measurement, the flange of the lid also closes the upper opening of the through hole, so that the fluid in the through hole is blocked from flowing to the outside. It Therefore, at the time of measurement, the fluid in the through hole does not flow out and the heat storage effect is exerted, so that a large damping effect can be obtained.

Further, the present invention is characterized in that the opening ends of the plurality of through holes are connected by a pipe line to form a flow path, and a fluid supply means for sending a fluid to the flow path is provided.

According to the means of (1), since the cooling medium or the like can be made to flow into the through hole by the fluid supply means, the heating furnace body after the measurement can be cooled more effectively. Further, even during measurement, if a coolant or the like is caused to flow through the through hole by the fluid supply means and the flow rate or the like is controlled, it becomes possible to perform a wider temperature control than in the case where only the heating means is used.

[0018]

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

1 to 4 show an embodiment of the present invention. FIG. 1 is a vertical cross-sectional perspective view showing the structure of a thermal analysis apparatus, FIG. 2 is a plan view of the thermal analysis apparatus, and FIG. FIG. 4 is a vertical cross-sectional perspective view showing the thermal analyzer during measurement, and FIG. 4 is a vertical cross-sectional perspective view showing the thermal analyzer during cooling. In addition, the same numbers are added to the components having the same functions as those of the conventional example shown in FIG.

In this embodiment, a thermal analysis device for performing differential scanning calorimetry will be described. As shown in FIGS. 1 and 2, the thermal analysis apparatus has a heating furnace body 1 having a cylindrical shape made of a material having a high thermal conductivity such as silver. This heating furnace body 1
A sample storage portion 1a, which is a circular concave portion having an opening on the upper surface, is formed in the center of the sample storage portion 1a, and the sensor unit 2 is stored in the sample storage portion 1a. The sensor unit 2 is shown in FIG.
The structure is similar to that of the conventional example shown in FIG. 1 and includes a plate 2a for mounting the sample container 3 and the reference material container 4, and a thermocouple wire 2b bonded to the back surface of the plate 2a. Around the sample storage portion 1a of the heating furnace body 1,
A plurality of through holes 1b penetrating straight in the vertical direction are formed so as to surround the sample storage portion 1a.

Sample storage section 1a in the heating furnace body 1
The central portion 5a of the lid 5 is fitted into the upper opening of the. The lid body 5 is a disk made of a material having a high thermal conductivity similar to that of the heating furnace body 1, and has a flange portion 5b at the peripheral edge portion. Then, as shown in FIG.
When the central portion 5a of the lid 5 is fitted into the sample storage portion 1a, the flange portion 5b closes the opening of the through hole 1b on the upper surface of the heating furnace body 1. Further, a heater wire 6 which is insulated from a heating wire and accommodated in a tube made of stainless steel or the like is wound around the outer peripheral side surface of the heating furnace body 1. Further, a temperature sensor 7 by a thermocouple is embedded slightly inside the outer peripheral side surface of the heating furnace body 1.

As shown in FIG. 1, the thermal analyzer having the above-described structure mounts a sample container 3 containing a sample 8 and a reference substance container 4 containing a reference substance 9 on a plate 2a of a sensor unit 2. Then, as shown in FIG. 3, the central portion 5a of the lid 5 is fitted into the upper portion of the sample storage portion 1a. Then, the heater wire 6 is energized by a controller (not shown) to perform the differential scanning calorimetry while controlling the temperature of the heating furnace body 1 according to the temperature program. At this time, the control device controls the energization to the heater wire 6 by feeding back the temperature T _f of the heating furnace body 1 detected by the temperature sensor 7, so that the temperature T _f is controlled as shown in FIG. Temperature control noise causes temperature fluctuations of amplitude n _c .

However, the heat from the heater wire 6 is transmitted to the sample storage portion 1a through the gaps between the through holes 1b and the through holes 1b themselves. The gap between the through holes 1b has a large thermal resistance because the conduction path made of the material of the heating furnace body 1 having a high thermal conductivity is narrowed by the through holes 1b on both sides. Further, the through hole 1b itself has a very low thermal conductivity due to an adiabatic effect of an inert gas such as nitrogen gas filling the inside thereof, so that the thermal resistance further increases. In addition, since the upper opening of each through hole 1b is closed by the flange portion 5b of the lid 5, the inert gas inside is blocked from flowing, and the heat storage property is increased. Therefore, in the heating furnace body 1, the heat from the heater wire 6 is transferred from the outer peripheral side surface to the central sample storage portion 1a.
A large damping effect due to the through-hole 1b is obtained when it is transmitted to the device 1. As shown in FIG. 7, the amplitude n of the temperature fluctuation generated in the temperature T _s of the sample 8 in the sample storage unit 1a is n
_d can be attenuated sufficiently.

When the differential scanning calorimetry is completed, the lid 5 is removed, the sample container 3 and the reference material container 4 are removed from the plate 2a of the sensor unit 2 as shown in FIG. Cool the body 1. At this time, the heating furnace body 1 has a through hole 1b that is larger than that of a conventional furnace of the same size.
Since the heat capacity is reduced by that amount, the amount of heat to be radiated is small, and the heat radiation is completed in a short time. Moreover, since the lid 5 is removed, the upper opening of each through hole 1b is opened to allow ventilation, so that the heating furnace main body 1 has a structure in which not only the upper and lower end surfaces and the outer peripheral side surface but also the inside of these through holes 1b are covered. The surface area by the peripheral surface is expanded, and the heat dissipation efficiency is increased. Furthermore, as shown by the arrow in FIG. 4, if an inert gas is forcibly blown from below with a blower or the like, this heat dissipation efficiency can be further improved.

As described above, according to the thermal analysis apparatus of this embodiment, the damping effect of the plurality of through holes 1b formed in the heating furnace body 1 sufficiently attenuates the temperature fluctuation due to the temperature control noise. Thus, the temperatures of the sample 8 and the reference substance 9 can be controlled. After the measurement is completed, heat can be efficiently dissipated through the through hole 1b.
It becomes possible to cool the heating furnace main body 1 in a short time and prepare for the next measurement.

In the above embodiment, the surrounding inert gas is allowed to flow into the through holes 1b as it is.
If a flow path is formed by connecting the openings of the above with a pipe, and a refrigerant such as liquid nitrogen or CFC cooled by a refrigerator is flowed through this, heat can be radiated more efficiently. Moreover, in this case, since the heating furnace body 1 can be positively cooled, the cooling rate of the heating furnace body 1 can be widely varied by adjusting the flow rate of the refrigerant and changing the cooling capacity. Be able to control.

Further, in the above embodiment, the heater wire 6 is wound directly on the outer peripheral side surface of the heating furnace body 1, but the heater wire 6 may be wound via a heat resistant heat insulating material such as cement or ceramic fiber. You may When such a heat insulating material is used, the heat radiation efficiency is deteriorated in the past, but in the present embodiment, the heat radiation efficiency from the through hole 1b can be prevented from being deteriorated. Moreover, by interposing such a heat insulating material between the heater wire 6 and the heater wire 6, the damping effect can be further improved by the heat storage effect of the heat insulating material.

Furthermore, in the above-described embodiment, the thermal analysis device for performing the differential scanning calorimetry has been described, but the same effect can be obtained when the thermal analysis device for performing another thermal analysis is performed.

[0029]

As is apparent from the above description, according to the thermal analysis apparatus of the present invention, the heat from the heating means is damped by the thermal resistance of the through hole, so that the temperature control noise transmitted to the sample storage portion causes The temperature fluctuation can be attenuated. Further, after the measurement, the heating furnace body can be rapidly cooled by the fluid flowing in the through hole.

[Brief description of the drawings]

FIG. 1 shows an embodiment of the present invention and is a vertical cross-sectional perspective view showing the configuration of a thermal analysis apparatus.

FIG. 2 shows an embodiment of the present invention and is a plan view of a thermal analysis device.

FIG. 3 shows an embodiment of the present invention and is a vertical cross-sectional perspective view showing a thermal analysis device at the time of measurement.

FIG. 4 shows an embodiment of the present invention and is a vertical cross-sectional perspective view showing a thermal analysis device during cooling.

FIG. 5 is a vertical cross-sectional perspective view showing a configuration of a thermal analysis device, showing a conventional example.

FIG. 6 is a time chart showing fluctuations in the temperature Tf of the heating furnace body affected by temperature control noise.

FIG. 7 is a time chart showing changes in the temperature Ts of a sample affected by temperature control noise.

[Explanation of symbols]

 1 Heating Furnace Main Body 1a Sample Storage 1b Through Hole 5 Lid 5b Collar 6 Heater Wire

Claims (1)

[Claims] 1. A thermal analyzer in which a sample storage unit for storing a sample is provided inside the heating furnace main body, and a heating means is provided around the heating furnace main body. A thermal analysis device, wherein a through hole is formed around the periphery of the.