JPH0769282B2 - Thermomechanical analyzer - Google Patents

Description

TECHNICAL FIELD The present invention relates to a thermomechanical analyzer for heating a sample and applying an appropriate load to measure the effect of the sample due to a thermal change.

[Prior Art] In a thermomechanical analyzer, a detection rod is brought into direct contact with a sample to heat it, and a dimensional change or the like of the sample is measured.
As a method of supporting the detection rod of such a thermomechanical analyzer, there is a method of using a balance mechanism in which a detection rod is attached to one end of the beam and a counter weight is attached to the other end. In the thermomechanical analyzer using this balance mechanism, the balance is balanced with the detection rod, differential transformer core, and force coil added, and the sample is changed and installed by moving the sample support tube up and down. .

[Problems to be Solved by the Invention]

In the thermomechanical analyzer of the balance type, since the sample is installed in the balance equilibrium state, when changing the sample, the sample support tube is moved by the driving or the motor. It is possible to change the sample by moving the detection rod with the load generated by passing an electric current through the force coil at some place, but even if you try to move the detection rod with the load from the force coil, the detection rod is stopped at an appropriate position. It is difficult to make it possible, and it is also difficult to adjust the moving speed.

The present invention has been made to solve such problems.

[Means for Solving the Problems]

That is, the present invention comprises a detection rod having a force coil and a differential transformer core, one end of which serves as a sample and which interacts with a permanent magnet, and a biasing means for biasing the detection rod upward.
A fixed block having the urging means attached thereto, to which a permanent magnet and a differential transformer coil are fixed, and the detection rod is freely moved in the axial direction and stopped by the action of the force coil and the permanent magnet. It is a thermomechanical analyzer characterized in that it is provided with means for making it.

[Work]

When changing the sample, first, no current is applied to the force coil and the load is set to zero. The length of the spring at this time is L ₀ .
Next, an electric current is passed through the force coil so that a force of ΔF is generated upward. If the spring flow at this time is L ₁ ,
With the spring constant being k, ΔF becomes “−k (L ₁ −L ₀ )”, and by increasing or decreasing the load ΔF of the force coil by an appropriate value, the detection rod can be stopped at an appropriate position.
In this way, after changing the sample, if ΔF is returned to zero again,
It is possible to return to a state where the sample and the detection rod are in contact with each other without a load.

〔Example〕

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

FIG. 1 is a vertical sectional view of an embodiment of a thermomechanical analyzer according to the present invention. In this figure, reference numeral 1 is a detection rod, the lower end of which contacts the sample M. Reference numeral 2 denotes a spring, one of which is connected to the upper end of the detection rod 1 and the other of which is connected to the fixed block 10.
3 is a force coil added to the detection rod 1, 4 is a permanent magnet, and a current is passed through the force coil 3 to apply a compressive and tensile load to the sample M via the detection rod 1 by the interaction of these. There is.

Reference numeral 5 is a differential transformer coil connected to the detection rod 1, and 6 is a differential transformer core, which detects a change in length of the sample M by the movement of the differential transformer core 6. Reference numeral 7 is a sample support tube, and the sample M is installed on the bottom and heated in an electric furnace 8.

As is clear from the above description, the detection rod 1, the force coil 3, and the differential transformer core 6 are integrally suspended by the spring 2, but these loads are normally applied to the sample M when the sample is not heated. It is in an equilibrium state so that it will not be applied. When a current is applied to the force coil 3 as described above, an appropriate load is applied to the sample M by the interaction between the force coil 3 and the permanent magnet 4. Further, during the thermal analysis, the sample M is heated in the electric furnace 8 and the sample length changes. The amount of this change is immediately detected as a change in the electrical signals of the differential transformer core 6 and the differential transformer coil 5, and the change is detected. The physical quantity such as the expansion coefficient of the sample M can be known from the quantity. The reference numeral 9 designates a micrometer, which is capable of measuring the sample length and manually moving the detection rod 1 through the block 10.

The configuration of the thermomechanical analyzer according to the present invention is as described above. Next, the sample changing operation will be described.
2 and 3 are simplified vertical cross-sectional views of the thermomechanical analyzer according to the present invention, showing how the sample is changed. Second
In the figure, the current is not passed through the force coil 3 and the load is zero, and the length of the spring 2 at this time is L ₀ .

Next, in FIG. 3, a current is passed through the force coil 3 so that a force of ΔF is generated in the upward direction. The length of the spring 2 at this time is L ₁ . Therefore, assuming that the spring constant is k, ΔF = −k (L ₁ −L ₀ ), and the detection rod 1 can be stopped at an appropriate position by increasing the load ΔF of the force coil 3 by an appropriate value. . In this way, after changing the sample, if ΔF is returned to zero again, it is possible to return to the state where the sample M and the detection rod 1 are in contact with each other in the unloaded state as shown in FIG.

The embodiment of the present invention is as described above.
Is a coil spring, but is not limited to the coil spring, and other biasing means such as an air spring or a leaf spring may be used. In addition, the mounting position is not limited to the upper end, but the fixed block 10
It may be locked to.

〔The invention's effect〕

Since the thermomechanical analyzer according to the present invention is configured as described above in detail, a force coil that originally has a role of adding an appropriate load to a sample when analyzing the sample is used for changing the sample and installing the sample. It can be used. Therefore, it becomes possible to dramatically improve the operability and speed up of the sample change and installation.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of an embodiment of a thermomechanical analyzer according to the present invention, and FIGS. 2 and 3 are simplified cross-sectional views of the thermomechanical analyzer according to the present invention, showing how a sample is changed. FIG. 1 ... Detection rod, 2 ... Spring, 3 ... Force coil, 4 ... Permanent magnet, 5 ... Differential transformer coil, 6 ... Differential transformer core, 7 ... Sample support tube, 8 ... Heating furnace, 9 ...... Micrometer 10 ...... Fixed block

Claims (1)

[Claims] 1. A detection rod having a force coil and a differential transformer core, one end of which contacts the sample and which interacts with a permanent magnet, a biasing means for biasing the detection rod upward, and the biasing means. A fixed block having a permanent magnet and a differential transformer coil fixed thereto, and means for freely moving and stopping the detection rod in the axial direction by the action of the force coil and the permanent magnet. A hot air mechanical analysis device characterized by the above.