JP2724844B2 - Thermomechanical measuring device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a thermomechanical measuring apparatus for detecting the amount of expansion and contraction of a solid sample due to a temperature change and observing the relationship between temperature and thermal expansion coefficient and the like.

Such a thermomechanical measuring device generally makes the lower end of a vertical detection rod come into contact with a sample placed in a furnace, and connects the upper end to an arm of a balance or the like, and adjusts the inclination of the balance due to a change in the temperature of the furnace. It is configured to detect and measure the thermal expansion coefficient or softening point of the sample. However, particularly at the time of measurement at a high temperature, there is a disadvantage that the detection value includes a noise component and the measurement accuracy is reduced. The present invention eliminates this drawback and provides an apparatus capable of performing highly accurate measurement even at a high temperature.

In the present invention, it has been found that the noise component is generated based on the vibration of the detection rod, and that the vibration is caused by the airflow generated by the temperature rise of the furnace flowing around the detection rod. , And a new configuration for preventing this can be obtained. That is, the device of the present invention arranges the convection prevention tube around the detection rod through a gap small enough to increase the gas flow resistance, thereby preventing the generation of the airflow rising or flowing along the detection rod. It is a configuration that prevents it. Therefore, it is possible to eliminate the drawback that the detection flow includes a noise component due to the vibration of the detection rod caused by the airflow.

FIG. 1 is a schematic view showing the structure of an embodiment of the present invention, in which a bar-shaped standard material 2 and a sample 3 corresponding thereto are vertically arranged inside an electric furnace 1 and detection rods 4 and 5 are provided on the upper surface thereof. The lower ends are in contact. A magnetic core 6 is attached to one of the detection rods 4, and a wire 7 of a position detecting differential transformer composed of a primary coil connected to an AC power supply and two secondary coils disposed on both sides thereof is attached to the other detection rod 5. , And the magnetic core 6 is arranged inside the wire loop 7. Therefore, the relative movement amount of the detection rods 4 and 5 in the vertical direction can be detected by the output of the wire ring 7. The upper ends of the detection rods 4 and 5 are connected to the arms of the balances 8 and 9, respectively, so that the weights 10 and 11 are balanced, and the lower ends of the detection rods 4 and 5 are appropriate for the sample and the like by the weights 12 and 13. The contact is made by pressure. For example, in such a thermomechanical measuring device, the present invention arranges sufficiently thin convection prevention tubes 14 and 15 around the detection rods 4 and 5 and places the appropriate positions on the base 1.
6 and the detection rods 4 and 5 and the convection prevention tubes 14 and 15
The gap between is set as small as possible, and the samples 2 and 3 are placed on a base 17 substantially connected to the base 16.

FIG. 2 is an enlarged view of the vicinity of the convection prevention tubes 14 and 15,
FIG. 3 is a sectional view taken along the line X-Y. That is, the bases 18 and 19 are not shown, but are integrally formed. A cylindrical body 20 is provided on a lower base 19 and the lower part thereof is a cylindrical electric furnace 1.
, And the base 18 is disposed above the cylindrical body. A convection prevention pipe is mounted on the base 16 where the cylindrical part of the base 18 is slidably fitted via an O-ring 21.
Fix the upper ends of 14, 15 and pass the cooling water to the bases 16, 18.
22,23 are provided. Further, the upper end of the sample support tube 24 is fixed to the base 16, and the base 17 shown in FIG. 1 is formed at the lower end thereof. Samples 2 and 3 are placed on the base and A window 25 for improving heat flow is formed on the side of the window. Further, a collar 26 is provided at an appropriate position of the support tube 24 to fix the lower portions of the convection prevention tubes 14 and 15 to prevent the vibration. That is, the present invention provides the convection prevention tubes 14 and 15 as described above, arranges them around the detection rods 4 and 5, and reduces the gap p between the inner surface of the pipes and the detection rod as small as possible. By sufficiently increasing the flow resistance of the flowing airflow, the detection rod is prevented from vibrating due to the airflow.

FIG. 4 is a curve showing an output change of the detection wire ring 7,
(A) is the conventional device, and (b) is the device of the present invention. That is, since the conventional device does not include the convection prevention tubes 14 and 15, the rising airflow generated by the temperature rise of the furnace 1 flows in large quantities around the detection rods 4 and 5, and this airflow is shaped by the equipment around the sample. An irregular route is taken and the route fluctuates every moment. Therefore, irregular vibrations are generated in the detection rods 4 and 5, and the vibrations are transmitted to the magnetic core 6, so that a large pulsation component is included in the detection signal as shown in FIG. That was not.
On the other hand, in the apparatus of the present invention, thin convection prevention tubes 14 and 15 are arranged around the detection rods 4 and 5, and the gap p therebetween is made sufficiently small. That is, since the flow resistance of the airflow flowing around the detection rods 4 and 5 becomes extremely high, the flow amount and the flow speed are remarkably reduced, and the airflow only moves upward from the bottom, and the horizontal direction is perpendicular to the horizontal direction. No components are generated. Therefore, the vibration of the detection rod is prevented, the pulsation component generated in the wire ring 7 is significantly reduced, and an accurate curve with a very small noise component can be observed as shown in FIG. 4b.

[Brief description of the drawings]

FIG. 1 is a view showing a configuration of an embodiment of the present invention, FIG. 2 is a longitudinal sectional view showing a detailed structure of a part of FIG. 1, and FIG. 3 is an XY section of FIG. FIG. 4 and FIG. 4 are curves illustrating the operation of the present invention. In the drawing, 1 is an electric furnace, 2 and 3 are standard samples and samples, 4 and 5 are detection rods, 6 is a magnetic core, 7 is a position detection wire, 14,
Reference numeral 15 denotes a convection prevention tube, 16, 17, 18, and 19 denote bases, and 24 denotes a sample support tube.

Claims (1)

(57) [Claims] 1. One end is brought into contact with a solid sample, and the flow resistance of the gas is high enough to increase the flow resistance around a vertical detection rod for detecting expansion and contraction of the sample due to a change in temperature according to the amount of movement of the other end. A thermomechanical measuring device, wherein a convection prevention tube is arranged via a gap.