JPH0240545A - thermomechanical analyzer - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] This invention relates to a thermomechanical analysis device for thermal analysis (applying a non-oscillatory load to a sample to detect the effects associated with chemical or physical changes in the sample). Thermo Mec, a device that measures
anical analysis (hereinafter referred to as TMA).

[Conventional technology]

In TMA, the detection rod is brought into direct contact with the sample and heated to measure changes in the dimensions of the sample.The detection rod can be supported by either a detection rod attached to one end of the beam or a balance with a counterweight attached to the opposite side. type, spring type that suspends with a spring,
There are methods such as a float type that utilizes buoyancy.

[Problem to be solved by the invention]

Among the support methods for the detection rod, in the balance type, when the detection rod moves up and down, the beam tilts, making it impossible to maintain the verticality of the detection rod. In addition, in the spring type, the spring expands and contracts as the detection rod moves, changing the pressure of the detection rod in contact with the sample, and in the float type, the volume of the submerged float changes as the detection rod moves (i.e., the float changes). There was a problem in that the buoyancy force decreased and the load on the sample changed, both of which caused measurement errors.

This invention was made in view of such problems,
The purpose is to provide a thermomechanical device that detects the amount of movement of a detection rod in the case of a spring type or a float type, and in which this movement does not affect the load applied to the sample.

[Means to solve the problem]

That is, in order to solve the above-mentioned problems, the present invention provides a thermomechanical analysis device that includes: (1) a movable table that moves on a sliding shaft; a drive mechanism that drives the movable table; one is a detection rod, and the other is a movable table; It is characterized by comprising a position detection differential transformer having a core connected to a spring attached to an end of the rod, and a controller that detects the amount of movement of the detection rod using the core and controls the drive mechanism. Alternatively, (1) a position detection differential transformer having a core, one of which is connected to a connecting rod that urges upward against gravity, and the other of which is connected to a detection rod that has a force coil in the middle; It is characterized by comprising a magnet provided opposite to the coil, and a controller that detects the amount of movement of the detection rod using the core and controls the force coil.

[For production]

In the case of the above method (2), assume that the heated sample expands and stretches a little. In this case, the detection rod also rises by that amount, but since the movable table remains stationary, the amount of extension of the spring becomes shorter by that amount. Therefore, the force supporting the detection rod decreases by "spring constant x amount of extension", but the load applied to the sample increases by that amount. Therefore, if the controller detects the amount of movement of the core in the differential transformer and drives the drive mechanism to move the moving platform by an amount corresponding to the amount of elongation, the amount of elongation of the spring increases by that amount, and the initial spring elongation increases. equals the amount. Therefore, the load applied to the sample becomes equal to that in the initial case, and the influence caused by the movement of the detection rod can be canceled.

In addition, in the case of method (2), if the sample is heated and expands and the detection rod is pushed up a little, this rise will reduce the biasing force on the member, and the load applied to the sample will increase accordingly. become. Therefore, if the controller detects the amount of movement of the core in the differential transformer and operates the force coil to apply a load corresponding to the increased amount, the increased amount can be canceled.

〔Example〕

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of the main parts of a thermomechanical analyzer according to the present invention in which the detection rod is supported by a spring type. In this figure, ■ is the core in the position detection differential transformer 2 (hereinafter referred to as core 1), 3 is the detection rod, and the detection rod 3 is the core l.
Connect to. Reference numeral 4 denotes a sample, which is placed in a sample support tube 6 fixed to a fixing table 5, and brought into contact with the detection rod 3.

Reference numeral 7 denotes a movable table, which is mounted so that it can move on a sliding shaft 9 via a bearing 8. Further, a spring 10 is attached to one end of the movable table 7, and the tip of the spring 10 is connected to the core l.

That is, one end of the core 1 is connected to the detection rod 3 and the other end is connected to the spring 10.
It is connected to. Further, a rack 11 is fixed to the other end of the movable table 7, and a binion 12 is driven by a motor 13.
are interlocking. Therefore, the movable table 7, spring 10, etc. are connected to the pinion 12, rack 11 and motor 13.
It is moved or displaced by a drive mechanism consisting of: Reference numeral 14 denotes a controller which receives signals from the differential transformer 2 and controls the motor 13. In addition, 15 is a heating furnace.

In the above configuration, when the sample 4 is heated by passing an electric current through the heating furnace 15, it is assumed that the sample 4 expands and extends by Δl. In this case, the detection rod 3 also rises by Δl, but since the movable table 7 remains stopped, the spring 10 stretches less by Δl. The spring constant of this spring 10 is 1
If so, the force supporting the detection rod 3 will decrease by "k, x Δl", but the load applied to the sample 4 will increase by "kl x Δl". Therefore, when the controller 14 detects the amount of movement of the core 1 in the differential transformer 2 and drives the motor 13 to drive the pinion 12 and rack 11 to move the movable table 7 by an amount corresponding to Δl, the spring 10 The amount of elongation increases by 61 minutes and becomes equal to the amount of elongation of the initial spring 10. Therefore, the load applied to the sample 4 is equal to that in the initial case, and the influence caused by the movement of the detection rod 3 can be canceled.

FIG. 2 shows a modified embodiment of the present invention, in which a differential transformer 16 and a core 17 for detecting the position of the movable table 7 are added. That is, as soon as the detection rod 3 moves by Δ1, the motor 13 is rotated so that the moving table 7 also moves by Δ1. In this embodiment, the motor 13 is not limited to a pulse motor, but may be any type that can stop immediately when the moving table 7 moves a predetermined distance. Even in this modified embodiment, the distance between the detection rod 3 and the moving table 7 remains the same, and even if the detection rod 3 moves, the sample 4
The load applied to will not change. Although the drive mechanism for the movable table 7 is based on the rack 11 and the pinion 12, it may be directly driven by a linear motor or the like.

Next, a case of a thermomechanical analyzer in which the detection rod is supported by a float will be described.

FIG. 3 is a longitudinal sectional view of the main parts of the float type thermomechanical analyzer. In this figure, 20 is a float which is placed in water in a water tank 21 so as to float thereon.

In this case, two floats 20 are used for balance reasons (however, the number of floats is not limited to two), but these floats are connected to the ends of a T-shaped connecting rod 22, and the other end of the connecting rod is used for position detection. It is connected to the upper end of a differential transformer core 1 (hereinafter referred to as core 1 in this embodiment). In this embodiment, the -L portion of the detection rod 3 is provided with a force coil 23 in the middle, and is connected to the core 1 via the force coil 23, and its lower end is brought into contact with the sample 4. Therefore, the detection rod 3 can be held in the air by the buoyancy obtained by submerging the float 20 into the water tank. A magnet 24 is placed opposite the force coil 23, and the differential transformer 2 and the magnet 24 are fixed to the case 25. In this embodiment as well, the sample 4 is placed on the sample support tube 6.

In addition, the force coil 23 is connected to the position detection differential transformer 2.
The controller 14 receives signals from the controller 14 and controls the controller 14.

In the above configuration, the detection rod 3 is brought into contact with the top of the sample 4 in order to obtain the expansion coefficient of the entire sample 4. The load on the tip of the detection rod 3 at this time is ro. It is assumed that the sample 4 is heated and expanded by the heating furnace 15 and the detection rod 3 is pushed up above Δl.

The flow) 20 rises due to Δl, and the part that was submerged in water is exposed, and the buoyancy decreases accordingly. If the volume of the exposed part is ΔV and the density of water is ρ, then due to the decrease in buoyancy, “Δ
The load applied to the sample increases by ``■×ρ''.

It is undesirable for the load to change when measuring the coefficient of expansion. However, when moving Δl, the buoyant force “Δ
If a load Δf corresponding to ``v×ρ'' is applied by the force coil 23, ``Δv×ρ'' can be canceled. Therefore, by detecting the amount of movement of the core 1 using the controller 14, the force coil 23 may be operated to control the force coil 23 so that the load Δr is applied.

FIG. 4 shows a modified embodiment in which a spring 30 is used in place of the float 20 and water tank 21 shown in FIG. That is, if the spring constant of this spring 30 is 2, and the detection rod 3 moves by Δ1, then if a force of 1×2×Δl is applied to the detection rod 3 by the force coil 23, even though it moves by ΔI. Regardless, the load applied to the sample 4 at the tip of the detection rod 3 does not change. In this example, core 1
A wide variety of members such as floats and springs can be used for the upper part of the body to resist gravity and urge the body upward.

〔Effect of the invention〕

Since the thermomechanical analyzer according to the present invention has the configuration as described in detail above, even if the detection rod moves due to thermal expansion of the sample and a load is applied to the sample, this can be canceled. Therefore, the initial load does not change, and more accurate thermal analysis becomes possible.

[Brief explanation of the drawing]

Fig. 1 is a vertical cross-sectional view of the main part of a thermomechanical analyzer in which the detection rod support method is a spring type according to the present invention, and Fig. 2 is a modified embodiment of the present invention, which shows the difference in detecting the position of the moving table. Example diagram when a dynamic transformer and core are added, Part 3
The figure is a longitudinal sectional view of the main part of a float-type thermomechanical analyzer, and FIG. 4 is a diagram of a modified embodiment in which a spring is used in place of the float and water tank of FIG. 3. 1-Core 2-.-Differential transformer for position detection 3-Detection rod 4-.-Sample 5-Fixing stand 6-Sample support tube
1-Moving table 8--bearing 9-sliding shaft 10-spring 11-rack 12--binion 13--motor 14-controller 15--heating furnace 16
-・Differential transformer 17・-core 20-float
21 - Water tank 22 series connection rod 23 - Force coil 2
4.-Magnet 25.-Case 30.-Spring Applicant: Shimadzu Corporation Representative Patent Attorney Masaki Kawasaki Figure 2 1--Core 2--Differential transformer 3-- - Detection rod 5 - 111 Fixed base 7 - 1 - Moving base 8 - 111 Bearing 9 - 1 - Sliding shaft 0 - Spring 1 - - Rack 2 - Binion 3 - --- Motor 4 --- Controller 6 --- Differential transformer 7 --- Core Figure 1 0-11 Spring 1 -- Rank 2 -- Binion 3 --- Motor 4 --- Controller 5----1 Heating Furnace Figure 3

Claims (2)

[Claims] (1) A position detection differential having a movable base that moves on a sliding shaft, a drive mechanism that drives the movable base, and a core connected to a detection rod on one side and a spring attached to the end of the movable base on the other. 1. A thermomechanical analysis device comprising: a dynamic transformer; and a controller that detects the amount of movement of the detection rod using the core and controls the drive mechanism. (2) A differential transformer for position detection having a core, one of which is connected to a connecting rod that urges upward against gravity, and the other of which is connected to a detection rod that has a force coil in the middle; and the force coil. 1. A thermomechanical analysis device comprising: a magnet disposed to face the core; and a controller that detects the amount of movement of the detection rod using the core and controls the force coil.