JPH0445777B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a differential scanning calorimeter used for thermal analysis.

B. Prior Art Conventionally, a differential scanning calorimetry analyzer heats or cools a reference material and a sample to be measured under the same conditions, detects the temperature difference between the reference material and the sample to be measured, and controls the difference to zero. This method requires a reference material, which makes analysis operations difficult, and it is also difficult to heat or cool the reference material and the sample to be measured under exactly the same conditions. Therefore, the sensitivity and accuracy could not be increased much.

C. Purpose The present invention provides a differential scanning calorimeter capable of thermal analysis, which does not require a reference material, can measure a sample to be measured alone, and eliminates the drawbacks of the prior art as described above. That is.

D. Configuration The differential scanning calorimeter according to the present invention has a configuration in which a sample is placed in an atmosphere in a heating furnace, heat is supplied from the heating furnace to the sample through a spatially limited heat flow path, and the heat source of this heat flow path is The structure detects the temperature at two points on the side and the sample side, controls the power supplied to the heater installed in contact with the sample so that the temperature difference becomes 0, and detects and records the amount of supplied power. have

The temperature difference between the two points in the heat flow path mentioned above is proportional to the amount of heat flowing through the heat flow path and supplied to the sample, and since the heater is controlled so that this temperature difference becomes 0, the supply to the heater Electric power is the amount of heat that a sample absorbs per unit time, and by measuring and recording this amount of heat, changes in the state of the sample can be known.

E. Example The figure shows an example of the present invention. In FIG. 1, 1 is a heating furnace, which is program-controlled to raise the temperature at a constant rate, and 2 is a sample to be measured.
3 is a metal plate for heat transfer, on which the sample 2 is placed. As shown in FIG. 2, the heat transfer plate 3 is a circular plate having a diameter smaller than the inner diameter of the furnace 1, and is provided with projecting pieces 3a on three sides, and these projecting pieces are embedded in the wall of the furnace 1. heat exchanger plate 3
The periphery of the is away from the inner wall of the furnace 1, and the sample is normally heated by heat transfer from the atmosphere inside the furnace, and the temperature increase rate is slow, so the temperature difference between the atmosphere, the furnace wall, and the sample is small. is almost 0, and the amount of heat transferred from the heat exchanger plate can be considered to be 0. When the sample enters the transformation point,
Since heat generation or absorption occurs suddenly, the supply of heat from the atmosphere with low thermal conductivity can be ignored, and the supply of heat from the furnace 1 is performed through the protruding piece 3a. That is, 3a becomes the spatially limited heat flow path mentioned above. The atmosphere inside the furnace is at approximately the same temperature as the inner wall of the furnace 1, and the sample placed on the heat exchanger plate 3 would be transferred from the furnace wall to the heat exchanger plate 3 through the protruding piece 3a unless there is a heater, which will be described later. It is heated by heat, and the temperature rises following the temperature of the atmosphere inside the furnace. Therefore, the output difference between the thermocouple T1 that is brought into contact with one point in the furnace wall of one of the protruding pieces 3a and the thermocouple T2 that is brought into contact with one point of the base of the protruding piece 3a on the heat exchanger plate 3 is equal to the output difference of the protruding piece 3a.
represents the amount of heat flowing through. Here, a surface heater 4 is attached to the back surface of the heat exchanger plate 3, and thermocouples T1 and T2
The power supplied to the surface heater 4 is controlled so that the output difference between the two becomes zero. P1 is a power supply circuit for the surface heater 4, and adjusts the power to the surface heater 4 so that the output of A1 becomes 0 by the output of an amplifier A1 that amplifies the output difference between the thermocouples T1 and T2. P2 is a power source for the heating furnace 1, and C is a program control circuit. The program control circuit C receives the output of the temperature sensor T3 that detects the ambient temperature inside the furnace 1, and controls the power supply P2 so that the temperature inside the furnace changes at a predetermined time rate.

With the above configuration, the power supplied to the heater 4 is controlled so that the output difference between the thermocouples T1 and T2 becomes 0, so the amount of heat flowing through the protruding piece 3a is 0, and the sample 2 is The temperature follows the atmosphere in the furnace and rises due to the amount of heat supplied from the furnace. W is a wattmeter that measures the power supplied to the heater 4;
The measured power value is recorded by the recorder R. For example, the record of this power value shows a constant value if the specific heat of sample 2 does not change, but if the specific heat changes due to a change in the state of the sample, a step will appear in the record, and when endotherm occurs due to a change in state, a peak will appear, and a peak will appear when heat is generated. When there is a change, a dent appears in the recording curve. Therefore, by recording this power value, changes in the state of the sample can be determined.

Effects The present invention has a configuration in which heat is supplied from a heating furnace to a sample through a limited heat flow path, and the sample is heated by a heater in contact with the sample so that the heat flow in this heat flow path is zero. Since the input to this heater is recorded, the amount of heat injected into the sample can be detected without using a reference material, which simplifies the measurement operation and eliminates the problem of discrepancies in heating conditions between the reference material and the sample to be measured. , it is possible to perform highly accurate measurements, and in particular, it uses a measurement zero position method that controls the heater so that the heat flow from the heating furnace to the sample becomes 0, so changes in the amount of heat supplied to the sample are minimized. This allows detection with even higher sensitivity.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view and circuit configuration of an apparatus according to an embodiment of the present invention, and FIG. 2 is a horizontal sectional view. 1... Heating furnace, 2... Sample, 3... Heat exchanger plate, 3
a...Protruding piece serving as a heat flow path, 4...Face heater, T
1, T2...Thermocouple, P1...Heater power supply, P2
... Heating furnace power supply, C ... Heating furnace power supply control circuit, W
...Power meter, R...Recorder.

Claims (1)

[Claims] 1 A configuration in which a sample is placed in an atmosphere within a heating furnace, a heat flow path is formed by a heat transfer body between the heating furnace and a heat transfer plate on which the sample is placed, and a heater is provided in contact with the heat transfer plate. Differential scanning characterized in that a control means is provided for controlling power supplied to the heater so that a temperature difference between two points on the heat flow path becomes zero, and the power supplied to the heater is detected and recorded. Calorimeter.