JPH06201622A - Differential scanning calorimeter - Google Patents

Abstract

(57) [Abstract] [Purpose] A detector with a simple structure similar to that of a differential scanning calorimeter or differential thermal analyzer of a heat flow rate ~ differential scanning that can perform thermal compensation for the heating furnace system and can also handle high temperature regions. Providing a calorimeter. A heating furnace 1 whose temperature is controlled by a heating furnace temperature detecting section 3 and a heating section control means 6, a stage driving mechanism 8 for driving a stage 7 on which the heating furnace 1 is mounted and fixed, and The temperature detection unit 2 arranged in the heating furnace, the temperature difference between the temperature of the heating furnace 1 and the temperature detection unit 2 of the sample and the reference material are detected and amplified, and the heating unit control means 6 and the stage drive mechanism 8 are detected. A differential scanning calorimeter comprising a temperature detecting / amplifying means 5 transmitted to the control means 9 of the above, and a recording means 10 recording the sample temperature of the temperature detecting portion 2 and the driving amount of the stage driving mechanism.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a kind of thermal analysis apparatus which heats a sample and a reference substance under the same conditions and measures the characteristics of the sample and the state change of the substance due to thermal changes as a function of temperature. It relates to a differential scanning calorimeter.

[0002]

2. Description of the Related Art In a differential scanning calorimeter, an analytical sample and a thermally inactive reference substance (reference substance) are simultaneously heated in the same environment to continuously detect the temperature difference. There are two types of calorimeters, which have different measurement principles: heat compensation type and heat flux type. The former compensates the heat absorption and heat generation of the sample with a micro heater built right under the sample and records the power, while the latter records the temperature difference between the sample and the reference substance and indirectly measures the heat absorption and heat generation. Is to seek.

[0003]

Generally, of the differential scanning calorimeters, the thermal compensation type is excellent in responsiveness, but the structure and control are complicated and it is difficult to increase the sensitivity, and the high temperature (800 ° C or higher) is required. Is hard to handle. In particular, in terms of structure, an extremely thin metal plate is often used as a microheater, and platinum is used for high temperatures, which poses a problem in terms of life. Further, mica or the like is used as an electrically insulating material between the micro heater and the sample container or the storage portion thereof, but this insulating mica or the like must be replaced with a ceramic plate or the like at a high temperature, so that it has a heat responsive surface. Becomes negative.

The present invention has been made in view of the above problems, and an object of the invention is to provide a detector-heating furnace system having a simple structure similar to that of a heat flow rate type differential scanning calorimeter or a differential thermal analyzer. It is an object of the present invention to provide a differential scanning calorimeter which can perform thermal compensation and can handle high temperature regions.

[0005]

That is, in order to solve the above problems, the present invention provides a differential scanning calorimeter in which a heating unit is arranged around a cylindrical portion and a heating furnace temperature detection unit and heating unit control means are provided. A temperature-controlled heating furnace, a stage drive mechanism for mounting and fixing the heating furnace on a stage and moving the stage horizontally, and a table on which a sample is mounted and a thermocouple is connected. A temperature detection unit, which comprises a base on which a reference material is placed and which is connected to a thermocouple, and which is arranged in the heating furnace, and transmits an amplification signal to the heating unit control means by detecting and amplifying the temperature of the heating furnace. A temperature detecting / amplifying means for detecting and amplifying the temperature difference between the sample temperature and the reference material temperature and transmitting the amplified signal to the control means for controlling the stage driving mechanism, the sample temperature of the temperature detecting section and the stage. Recording means for recording the drive amount of the drive mechanism, Characterized in that it comprises Ri.

[0006]

The operation when the differential scanning calorimeter is used as the above means will be described with reference to the reference numerals in the accompanying drawings (FIGS. 1 to 3). The heating furnace 1 is heated, the temperature inside the heating furnace 1 is measured by the thermocouple 3, and the measured temperature T _f is fed back to the heater control circuit 6 via the temperature detection / amplification circuit 5. The temperature difference ΔT between the sample and the reference substance is fed back to the motor control circuit 9 via the temperature detection / amplification circuit 5. When the sample changes in heat generation and the sample temperature rises, the stepping motor 8 is driven to move the sample container 21 and the table 23 on which the sample is placed away from the inner wall 1w of the heating furnace 1 so as to increase the thermal resistance ( At this time, at the same time, the sample container 22 and the table 24 on which the reference material is placed and the inner wall 1w of the heating furnace 1 approach each other, and the thermal resistance decreases. In this way, the amount of heat supplied to the sample (compared to the reference substance) is suppressed (FIG. 2B). vice versa,
When the sample undergoes an endothermic change, the sample and the inner wall 1w of the heating furnace 1
And close to increase the amount of heat supply to the sample (Fig. 2
(C)). The rotation angle θ of the drive shaft 81, which is the amount of movement of the heating furnace 1, is recorded as a heat compensation signal.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Specific embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view of an essential part of the entire differential scanning calorimeter of the present invention, and FIG. 2 is a sectional view taken along the line AA of FIG. In these figures, reference numeral 1 denotes a cylindrical heating furnace in which the circumference of the cylindrical portion is wound with a heater wire 11 which is a heating portion, and a heating furnace temperature controlling thermocouple 3 is attached. The temperature T _f of the heating furnace 1 is the thermocouple 3 which is the heating furnace temperature detecting section.
Then, the temperature is measured and fed back to the heater control circuit 6 via the temperature detection / amplification circuit 5 for control. Reference numeral 4 is a cold junction of the thermocouple 3.

A mounting base 12 is fixed to the lower portion of the heating furnace 1, and the mounting base 12 is further mounted and fixed to the heating furnace stage 7. Reference numeral 8 is a stepping motor for driving the heating furnace stage 7, which is a drive shaft 81 attached to the central portion.
A threaded portion 81a is threaded on the screw and the screwed portion 81a is screwed into the heating furnace stage 7. This drive mechanism may be replaced with other means such as a linear motor, a gear mechanism or a belt mechanism.

Next, 2 is a temperature detector, which is installed in the center of the inside of the heating furnace 1. The temperature detector 2 is shown in FIG.
As shown in (A), a sample temperature detecting section 2a including a container 21 for containing a sample and a table 23 on which the sample container 21 is placed.
And a reference material temperature detecting section 2b including a container 22 for containing the reference material and a table 24 on which the reference material container 22 is placed,
Further, thermocouples 25 and 26 are connected to the table 23 for the sample container 21 and the table 24 for the reference material container 22 (see FIG. 3 for the connection state of the thermocouple). The thermocouple of the detector 2 is passed through the vertically elongated insulator tube 27 to form the heating furnace stage 7
It is connected and fixed to the thermocouple cold junction 28 through a hole formed in the. The stepping motor 8 and the cold junction 28 of the thermocouple are mounted and fixed to the frame 13.

The detected temperature T _f of the heating furnace 1 is
The heater control circuit 6 is detected and amplified by the amplifier circuit 5.
And is fed back to control the internal temperature of the heating furnace 1.
Further, the temperature T of the sample temperature detecting section 2a of the temperature detecting section 2 is
_s and the temperature difference ΔT between the temperature of the sample temperature detector 2a and the temperature of the reference substance temperature detector 2b are fed back to the motor control circuit 9 via the temperature detection / amplification circuit 5 so that ΔT becomes zero. Then, the stepping motor 8 is driven. The stepping motor 8 rotates the drive shaft 81 to move the temperature detecting section 2 in the heating furnace 1 in the horizontal direction. In this case, the temperature T _s of the sample temperature detector 2 a and the rotation angle θ (driving amount) of the drive shaft 81 of the stepping motor 8 are recorded by the recording unit 10. The recording unit 10 may be a normal recorder or a memory such as a personal computer.
Further, the feedback control may use an electric circuit,
The program may be controlled by a personal computer or the like.

The embodiment of this differential scanning calorimeter is as described above. Next, the operation in the case of measuring the temperature difference between the sample and the reference substance is shown in the attached drawings (FIG. 2 (B) and FIG. 2 (C)). )
Will be described using the reference numerals of the respective constituent elements. In the heating furnace 1, a sample temperature detecting section 2a and a reference material temperature detecting section 2b are installed and heated. The temperature in the heating furnace 1 is measured by the thermocouple 3, and the measured temperature T _f is fed back to the heater control circuit 6 via the temperature detection / amplification circuit 5. The temperature difference ΔT between the sample and the reference substance is fed back to the motor control circuit 9 via the temperature detection / amplification circuit 5. When a change in heat is generated in the sample and the sample temperature rises (compared to the reference material temperature), the stepping motor 8 is driven to move the sample container 21 on which the sample is placed, the table 23 and the inner wall 1w of the heating furnace 1. Keep away from each other so that the thermal resistance increases (at this time, the sample container 22 and the base 2 on which the reference substance is simultaneously placed.
4 and the inner wall 1w of the heating furnace 1 approach each other, and the thermal resistance decreases). In this way, the amount of heat supplied to the sample (compared to the reference substance) is suppressed (FIG. 2B). Conversely, when the sample undergoes an endothermic change, the sample and the inner wall 1w of the heating furnace 1 are brought close to each other to increase the amount of heat supplied to the sample (FIG. 2 (C)). The rotation angle θ of the drive shaft 81, which is the amount of movement of the heating furnace 1, is recorded as a heat compensation signal. FIG. 4 shows the above-mentioned thermal change (temperature T _s of the sample temperature detecting portion 2a).
Alternatively, the time t is plotted on the horizontal axis and the rotation angle θ of the drive shaft 81 of the stepping motor 8 is plotted on the vertical axis, and the differential scanning calorimeter curve (DS
(C curve).

In the above embodiment, the feedback circuit between the temperature difference ΔT between the sample and the reference material and the rotation angle θ of the drive shaft 81 of the stepping motor 8 is cut off (that is, the position of the heating furnace 1 is fixed. ) Then, a normal differential thermal analyzer (DT
It can be used as A). In this case, the rotation angle θ
Record ΔT instead of

[0013]

Since the differential scanning calorimeter of the present invention is configured as described above in detail, it is similar to the conventional thermal compensation type differential scanning calorimeter in comparison with the conventional thermal compensation type differential scanning calorimeter. The differential scanning calorimeter can be used. Further, this differential scanning calorimeter is particularly excellent in thermal stability in a high temperature range because the structure of the heating furnace is the same as that of the conventional differential thermal analyzer (DTA device). Further, since this differential scanning calorimeter does not need to use a micro heater, it becomes easy to raise the temperature of the apparatus.

[Brief description of drawings]

FIG. 1 is a perspective view of an essential part of an entire differential scanning calorimeter of the present invention.

2 is a cross-sectional view taken along the line AA of FIG. 1 and is shown in FIG.
Shows a state in which the container on which the sample of the temperature detecting unit is placed and the wall of the heating furnace and the container on which the reference substance is placed are placed at positions equidistant from the wall of the heating furnace. FIG. 2C shows a state in which the container on which the sample is placed and the wall of the heating furnace are separated from each other so as to increase the thermal resistance. FIG. 2C shows a state in which the container on which the sample is placed and the wall of the heating furnace are close to each other. Show.

FIG. 3 is a diagram showing a configuration of a temperature detection unit in which thermocouples are respectively connected to a sample container base and a reference material container base.

FIG. 4 is an example diagram of a differential scanning calorimeter (DSC) curve in which the horizontal axis represents the sample temperature T _s or time t of the sample temperature detection unit and the vertical axis represents the rotation angle θ of the drive shaft of the stepping motor.

[Explanation of symbols]

1 heating furnace 11 heater wire 1
2 Mounting base 13 Frame 2 Temperature detector 2a Sample temperature detector 2
b Reference Material Temperature Detector 21 Sample Container 22 Reference Material Container 2
3 Sample container stand 24 Reference substance container stand 25, 26 Thermocouple
28 Cold Junction 3 Thermocouple 4 Cold Junction 5
Temperature detection / amplification circuit 6 Heater control circuit 7 Heating furnace stage 8 Stepping motor 81 Drive shaft 9 Motor control circuit 10 Recording unit

Claims (1)

[Claims] 1. A heating furnace in which a heating portion is arranged around a cylindrical portion and whose temperature is controlled by a heating furnace temperature detecting portion and a heating portion control means, and the heating furnace is mounted and fixed on a stage and the stage. Temperature detection, which consists of a stage drive mechanism that moves the sample horizontally, a table on which a sample is placed and a thermocouple is connected, and a table on which a reference material is placed and a thermocouple is connected. Section and the temperature of the heating furnace are detected and amplified to transmit an amplified signal to the heating section control means, and a temperature difference between the sample temperature and the reference material temperature is detected and amplified, and the amplified signal is driven to the stage. A differential scanning calorimeter comprising: temperature detecting / amplifying means for transmitting to a control means for controlling the mechanism; and recording means for recording the sample temperature of the temperature detecting portion and the drive amount of the stage drive mechanism.