JPH0656369B2 - Thermal analyzer - Google Patents

Description

The present invention relates to a furnace for accommodating and heating or cooling a sample and a standard sample, particularly a part for holding the sample and the standard sample when performing a differential thermal analysis or other thermal analysis. Regarding configuration.

In a differential thermal analysis or a differential scanning calorimetric analysis, in a vertical cylindrical furnace made of, for example, silver, which has good thermal conductivity, a disk-shaped disc formed of constantan or platinum / rhodium alloy or gold / palladium alloy is used. There is used an apparatus in which a heat sensitive plate is horizontally arranged, its peripheral edge is fixed to, for example, a central portion of a side wall of a furnace by welding or the like, and a sample and a standard sample are placed on the heat sensitive plate. However, Constantan has the drawback of low oxidation resistance and corrosion resistance, and the latter has a small coefficient of thermal expansion, which is about half that of silver, so the case of raising the furnace temperature from room temperature to 700 degrees will be described. Then, the inner diameter of the furnace becomes about 0.15 to 0.2 mm larger than the diameter of the heat sensitive plate, and tension is applied to this heat sensitive plate. Therefore, there is a drawback that the base line of the measurement curve is bent due to the displacement of the sample and the like due to the irregular distortion and deformation of the heat sensitive plate due to the rise of the furnace temperature, which causes the measurement error.
Therefore, the present invention provides an apparatus which does not have the above-mentioned drawbacks even when the furnace body and the heat sensitive plate on which the sample and the like are mounted are formed of different kinds of metals and the like.

The present invention forms a horizontal sample mounting portion in the center of the heat sensitive plate,
Independent supporting vanes are provided on each side of the supporting vanes, and the supporting vanes are bent twice to form a rising portion and a horizontal supporting portion on the supporting vanes. A sample support table, which is fixed to the side wall of the body, and on which a sample and a standard sample are respectively placed, is formed symmetrically in the center of a horizontal sample placing portion. Therefore, if the difference between the diameter of the horizontal sample mounting portion and the inner diameter of the furnace body fluctuates with the temperature change due to the difference in the coefficient of thermal expansion between the heat sensitive plate and the furnace body, the rising portion of the supporting blade is easily inclined. Then, the fluctuation part is absorbed. Therefore, there is no risk of irregular bending of the horizontal sample mounting part, and it is possible to stably hold the sample and standard sample at a fixed position in the furnace and prevent the bending of the baseline due to their movement. it can.

FIG. 1 is a view showing a vertical cross section and an electrical configuration of a furnace body in a differential scanning calorimeter of the present invention. A platinum-rhodium alloy heat-sensitive plate is provided inside a bottomed cylindrical furnace body 1 made of silver. 2 are arranged horizontally, and the periphery thereof is inserted into an annular groove in the side wall of the furnace body and completely fixed by welding or the like. The sample container 5 and the standard sample container 6 are placed on support bases 3 and 4 formed in the center of the heat sensitive plate 2 in an axially symmetrical manner, and a thermoelectric material of gold-palladium alloy is placed on the lower surface of the support base 3.4. One end of each pair of wires 7.8 is attached. These thermocouple wires are connected to the differential temperature detector 9, and the platinum / rhodium thermocouple wire 10 and the thermocouple wire 7 connected to the support 3 on which the sample container 5 is placed are connected to the sample temperature detector 11. Although not shown, the furnace body 1 is sealed by a lid 12 and the furnace body 1 is housed in an electric heater and the temperature is gradually increased at a predetermined rate to connect the sample at each temperature. The differential temperature between the standard and the standard sample is detected. That is, the differential scanning calorimetric analysis can be performed by such an apparatus.

FIG. 2 is a plan view of the heat sensitive plate 2 in the above apparatus, and FIG. 3 is a sectional view taken along line AA of FIG. That is, the circular heat-sensitive plate 2 has a large number of notches 13.13 ... Formed at equal intervals on the periphery thereof, and the portion sandwiched between the notches is bent twice at an angle close to a right angle to form a regular polygon in the center. The sample mounting portion 14 is formed, and independent supporting wings 15.15 ... Are formed on each side thereof. This support wing 1
5.15 ... The end of the furnace body 1 made of silver with good heat conduction
Of the sample or the standard sample container 5.6 is placed on the support stand 3.4 as shown in FIG. Perform an analysis. In addition, if necessary, the central sample mounting portion 14
Ribs 16.17 and the like for preventing the bending of this portion are formed in appropriate positions at appropriate positions, and although not shown, the lower surface of the support base 3 has a gold-palladium alloy thermocouple wire 7 and platinum. The rhodium thermocouple wire 10 is connected, and the gold-palladium alloy thermocouple wire 8 is connected to the lower surface of the support 4.

In the apparatus of the above-mentioned embodiment, a large number of cuts 1 are formed on the periphery of the heat sensitive plate 2.
3.13 ... is provided, the part sandwiched by the notches is bent twice at a substantially right angle, and the peripheral edge is fixed to the side wall of the furnace body 1. Therefore, the sample mounting portion 14 at the center is formed in a polygonal shape, and a flat portion substantially perpendicular to each side thereof is connected, and horizontal straight bent portions are provided at both ends of the flat portion. To be Therefore, when the sample mounting portion of the heat sensitive plate relatively expands or contracts in the horizontal plane due to the difference in the coefficient of thermal expansion between the furnace material and the heat sensitive plate, the inclination angle of the portion sandwiched by the notches 13 that rises at a substantially right angle is easy. To absorb the expansion and contraction. Therefore, there is no possibility that a large strain force is applied to the horizontal sample mounting portion 14 and the portion is bent or deformed. Therefore, the sample position is moved or the container 5.6 is tilted. Thus, the drawbacks that cause a large measurement error are eliminated.

[Brief description of drawings]

FIG. 1 is a view showing a longitudinal section of an embodiment of the present invention and an electrical configuration of the apparatus, and FIG. 2 is a plan view of a heat sensitive plate in FIG.
FIG. 3 is a sectional view taken along the line AA of FIG. In the figure, 1 is a furnace body, 2 is a heat sensitive plate, 3.4 is a sample support, 13 is a notch, 14 is a sample mounting portion, 15 is a support blade, and 7.8.10 is a thermocouple wire.

Claims (2)

[Claims] 1. A sample is placed at the center of the heat sensitive plate by forming a plurality of cuts in the radial direction on the peripheral edge of the heat sensitive plate having a substantially circular shape and bending each part sandwiched by the cuts twice. A part is formed and each side is
An independent supporting vane consisting of a rising part and a horizontal supporting part is formed, and the tip of each supporting vane is fixed to the side wall of a cylindrical furnace body made of a material having good heat conduction, and the sample is placed on the side. A thermal analysis device in which a sample support base on which a sample and a standard sample are respectively placed is formed axisymmetrically, and thermocouple wires are connected to the sample support base. 2. A polygonal sample mounting portion is formed in the center of a heat sensitive plate by forming a large number of the notches at equal intervals and bending each part sandwiched by the notches twice at substantially right angles. The thermal analysis device according to claim 1, wherein