JPH03255349A - Detecting device for temperature of specimen in thermal analysis apparatus - Google Patents

Abstract

PURPOSE:To measure temperature accurately even if the bonding positions of wires to a specimen holder are separated and to facilitate bonding work by forming the specimen holder of the same material as that of one wire of two wires forming a thermocouple. CONSTITUTION:A specimen pan 6 containing a standard specimen is mounted on a standard-specimen mounting part 9 of a spec holder 3. A specimen pan 7 containing a specimen to be measured is mounted on a specimen-to-be- measured mounting part 10. Wires 11 forming the positive side of a thermocou ple are bonded to the mounting parts 9 and 10. A wire 12 forming the negative side of the thermocouple is bonded to the lower side of the holder 3. As the material for the holder 3, the same material as that of the wire 12 is used. Therefore, even if the bonding positions of the wires 11 and 12 to the holder 3 are separated, the holder 3 itself acts as the wire of the thermocouple, and the accurate temperature measurement can be performed. In this way, the bonding positions of the wires can be selected arbitrarily, and the bonding work can be made easy.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention relates to a sample used in a thermal analyzer in which both a standard sample and a measurement sample are placed on a sample holder and the measurement sample is thermally analyzed. This invention relates to a temperature detection device.

In particular, the present invention relates to a sample temperature detection device that detects the temperature of both a standard sample and a measurement sample using a thermocouple.

[Prior Art] It is already well known that thermal analysis apparatuses such as those described above include, for example, a differential thermal analyzer (DTA instrument H), a differential thermogravimetric analyzer (TG-DTA instrument), and the like.

As is well known, a DTA device changes the temperature of a standard sample, such as alumina, and the measurement sample, which is the object of measurement, according to a fixed program, and then measures the state of change in the temperature difference between the two using I! This is used to determine whether a state change such as metastasis or melting has occurred in the measurement sample.

In addition, the TG-DTA device measures changes in the temperature difference between the standard sample and the measurement sample as described above, and also measures how the weight of the measurement sample changes in response to temperature changes. This is what I am trying to do.

In each of the above devices, it is necessary to detect the temperature of both the standard sample and the measurement sample.

As a means for such temperature detection, a temperature detection device using a thermocouple is conventionally known.

In general, a thermocouple measures temperature based on thermoelectromotive force generated between two different types of metals, and usually two wires, a positive wire and a negative wire, are joined and the junction point is Detects the temperature of

Therefore, when trying to measure the temperature at two locations of the standard sample and the measurement sample, as in the above-mentioned DTA device or TG-DTA device, two wires are connected at one point on the standard sample placement part of the sample holder. It is necessary to join the two wires to each other, and also to join the two wires to each other at one point on the measurement sample mounting section.

It is very difficult to join two wire rods together at one point, and the difficulty becomes even greater when the above-mentioned devices have to perform this work on four wire rods.

By the way, when heating a sample to an extremely high temperature such as 2400"C, tungsten (W) is used as a thermocouple material.
) type materials will be used. Since simple welding methods such as spot welding cannot be applied to this type of material, the above-mentioned wire joining operation becomes even more troublesome.

In order to solve the difficulty of such work, the present inventor attempted to connect two wires to the standard sample placement part or the measurement sample placement part of the sample holder while keeping them separated from each other. Ta. This is because the degree of freedom in selecting the joining position when joining the four wires to the sample holder increases, making the work easier. However, various experiments have shown that simply separating two wires and joining them does not generate an accurate thermoelectromotive force corresponding to the actual temperature, and therefore it is not possible to measure temperature accurately. I understand.

[Problems to be Solved by the Invention] The present invention has been made in view of the above points, and relates to a thermocouple used in a sample temperature detection device for a thermal analysis device, and relates to its assembly, particularly to a sample holder. It is an object of the present invention to provide a temperature sensing device that can smoothly perform the bonding.

[Means for Solving the Problems] In order to achieve the above object, the sample temperature detection device according to the present invention has a sample temperature detection device in which the material of the sample holder for placing the standard sample and the measurement sample is made of a material constituting the thermocouple. It is characterized by being made of the same material as the first wire rod or the second wire rod.

In the sample temperature detection device of the second aspect, the sample holder is made of the same material as the 112 wire. The second wire here refers to a wire that is different from the wire that is connected to each sample placement part of the sample holder (in other words, the first wire), and usually serves as the reference side for thermocouple measurement. This is the wire on the negative side.

In particular, in the apparatus according to the second aspect of the present invention, this W2 wire is constituted by one wire. In other words, the number of wires used in the thermocouple in this invention is three in total.

The sample temperature detection device according to the third aspect of the present invention assumes a case where the temperature around the sample holder becomes extremely high, such as 2400'C. In this case, each wire and sample holder are formed from a tungsten-rhenium (W-Re) alloy. For example, the first wire (usually the positive wire) to be joined to each of the standard sample placement part and the measurement sample placement part of the sample holder is made of 3% W-Re, and the sample holder and the first wire connected to it are made of 3% W-Re. The two wires (usually the wire on the negative common side) can be made of 25% W-Re.

[Function] In the sample temperature detection device of claim 1, the sample holder (
3) Part 9 itself is the wire on one side of the thermocouple.

That is, it acts as the first wire (11) or the second wire (12). Therefore, even if the first wire and the second wire are not actually connected directly but are indirectly connected via the sample holder, there is no problem in functioning as a thermocouple.

Since the first wire rod and the second wire rod can be separated from each other on the sample holder and joined to the sample holder in this way, when two of each wire rod is used (in other words, the temperature at two locations is ), as in the invention of claim 2.

The minus side wire of the thermocouple (the second wire 12 in the example) is 1
It becomes possible to share the same wire material. This makes the work of joining the thermocouple wire to the sample holder much easier, and furthermore, the cost for one wire becomes cheaper.

The temperature detection device according to claim 3 is capable of detecting temperature at an extremely high temperature of 2400°C. W-based wire is a material that is difficult to join, for example, weld, but by adopting the structure of claim 1 or claim 2, the difficulty of joining is reduced.

[Embodiment] FIG. 1 shows an embodiment of a sample temperature detection device according to the present invention. Further, FIG. 2 shows a case where the temperature detection device is used in a thermal analysis device, for example, a differential thermogravimetry device (TG-DTA device).

First, the Jllll device will be briefly explained.

A cylindrical heater 2 is placed in a heating furnace 1, and a sample holder 3 is placed in a position surrounded by the heater 2. This sample holder 3 is supported on a balance 5 via a support 4.

Two sample plates 6 and 7 are placed on the sample holder 3. One sample plate, for example sample plate 6, houses a standard sample 1, for example alumina, and the other sample plate 7 houses a measurement sample. has been done.

The heater 2 is configured to generate heat based on a predetermined program, and the standard sample and the measurement sample are heated by the heater 2. A thermocouple (described in detail later) consisting of two first wire rods 11 and one second wire rod 12 is joined to the sample holder 3. Each of these wires passes through a disk-shaped wire holder 16, and further passes through the support 4 and is connected to the temperature detection circuit 13. Based on the thermoelectromotive force generated in these wires, the temperature detection circuit 13 detects the temperature difference between the standard sample and the measurement sample, so-called differential heat.

On the other hand, a weight detection circuit 14 is connected to the balance 5.

When there is a weight change in the measurement sample heated by the heater 2, the balance 5 vibrates and rotates around the fulcrum 15, and the weight detection circuit 14 detects the weight change of the measurement sample based on the vibration rotation. .

Reference numeral 8 in FIG. 2 is a reflector that prevents radiation heat from dissipating.

Hereinafter, a thermocouple constituted by the first wire 11 and the second wire 12 will be explained.

As shown in Figure 1, the sample m in which the standard sample is stored
6 is placed on the standard sample mounting portion 9 of the sample holder 3. On the other hand, if! l Sample tray 7 in which constant samples are stored
Ha, ll! 1 is placed on the constant sample holder device 0. Two first wire rods 1 that constitute the positive side of the thermocouple
1.11 is the standard sample placement section 9 and the sub-chamber sample placement section 1
Junction to each of 0.

For example, it is welded. And the negative side of the thermocouple (
One second wire rod 1 that is a wire rod constituting a common fill
2 is joined, for example welded, to the lower part of the sample holder 3.

In this case, the same material as the 112 wire rod 12 is used for the sample holder 3. For example, now the sample is 2400'
Considering that it will be heated to an extremely high temperature such as C, 3% W-Re (tungsten/rhenium) is used as the 311 wire (positive side) and 25% W-Re is used as the second wire (minus 1ll). In this case, the sample holder 3 is made of 25% W-Re.

In this example, the material of the sample holder 3 is the same as that of the wire constituting the thermocouple (the same material as the j12 wire in this example), so as shown in FIG.
Even when the first and second wire rods 12 are connected to the sample holder 3 at a distance from each other (that is, when the thermocouple wires are not directly connected), accurate temperature measurement can now be performed. This is thought to be because the sample holder 3 itself is formed as a thermocouple wire.In this way, each wire 11 and 12 is connected to a separate location on the sample holder. Since it can be done, any position can be selected as the joining position, and as a result, the joining operation has become very eastern.

Also, the common side is a negative wire! Since only one wire rod 12 is required, resulting in a total of three thermocouple wire rods, the work of joining and other assembling of the wire rods becomes even easier.

As mentioned above, if a tungsten (W)-based material is used as the thermocouple material, it is difficult to weld this W-based material with a simple welding method such as spot welding.
Requires special welding methods.

In this case, it would be extremely convenient if the number of thermocouple wires could be as small as three as in this embodiment. Furthermore, since the number of required wire rods is reduced, costs can also be kept low.

Although the present invention has been described above with reference to one embodiment, the present invention is not limited to that embodiment.

For example, the sample temperature detection device according to the present invention is not limited to the TG-DTA type thermal analysis device as shown in FIG. 2, but can be applied to any other thermal analysis device.

The material of the sample holder 3 is the minus side wire material (the second wire in the example).
It is not limited to the wire rod 12), but may also be a positive wire rod (first wire rod 11 in the embodiment).

[Effects of the Invention] According to the invention of claim 1, since the sample holder is formed of the same material as one of the two wires constituting the thermocouple, the two wires can be used as the sample holder. Accurate temperature measurements can be made even if they are joined apart from each other rather than directly joined at one point above.

As a result, it became possible to freely set the joining position of each wire rod, making the joining work much easier.

In particular, as described in claim 2, it is also possible to use only one wire on the common side of the thermocouple, and in this case, the total number of wires becomes three, and the wires are joined to the sample holder. becomes even easier.

According to the third aspect of the invention, temperature detection at an extremely high temperature of 2400°C is possible. Tungsten materials are
It is difficult to apply simple welding methods such as spot welding, and special welding methods must be used. In this case, if the joining of each wire rod was easy for the above reasons,
This is extremely convenient for workers.

[Brief explanation of drawings]

FIG. 1 is a perspective view showing an embodiment of the sample temperature detection device according to the present invention, I! Reference numeral 211 is a side sectional view showing a thermal analysis device using the sample temperature detection device. 3...Sample holder 9...Standard sample placement part O...Measurement sample placement part 11...First wire of thermocouple 12...Second wire of thermocouple -r Q. Fig. 1 ↓ C, tJ button and l to Engineer-13 Fig. 2

Claims (3)

[Claims] (1) Used in a thermal analysis device that performs thermal analysis of a measurement sample by placing both a standard sample and a measurement sample on a sample holder,
A temperature detection device that detects the temperature of both of the samples using a thermocouple, the thermocouple being composed of a first wire and a second wire, the first wire being a standard wire of the sample holder. The second wire is connected to each of the sample holder and the measurement sample holder, and the second wire is connected to any position of the sample holder, and the sample holder is made of the same material as the first wire or the second wire. A sample temperature detection device characterized by: (2) The sample temperature detection device according to claim 1, wherein the sample holder is made of the same material as the second wire, and the second wire is a single wire. (3) The sample temperature detection device according to claim 1 or 2, wherein the first wire, the second wire, and the sample holder are made of a tungsten-rhenium (W-Re) alloy.