JP2002071603A - Thermal analyzer, thermal analysing measuring method, and gas flow unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform highly reliable measurement by preventing variations in internal pressure from being produced within a sample chamber in a thermal analyzer for measuring by setting the concentration of oxygen low around a sample by forming separate gas flows within the sample chamber. SOLUTION: This thermal analyzer has a first opening 01 formed in the sample chamber 2 for disposing the sample S therein and a gas supply port 13 for supplying gas to the sample chamber 2. The thermal analyzer further has a second opening 02 provided on the opposite side to the first opening 01 relative to the position where the sample S is disposed and a gas carrying pump 23 connected to the second opening 02. By sucking the gas by the carrying pump 23, the inert gas taken in from the supply port 13 is made to flow, within the sample chamber 2, separately in the direction of the first opening 01 and in the direction of the second opening 02. The first opening 01 is open to the exterior and the interior of the sample chamber 2 is kept at the external pressure at all times.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a thermal analyzer for measuring the temperature dependence of the properties of a sample while changing the temperature of the sample. The present invention also relates to a thermal analysis measurement method performed using the thermal analyzer. Further, the present invention relates to a gas flow unit suitably used for the thermal analyzer.

[0002]

2. Description of the Related Art Various types of thermal analyzers have been known. For example, TG (Thermogravim) which measures the temperature dependence of the weight of a sample while changing the temperature of the sample
etry) equipment, DTA (Differential Thermal Analysis) equipment that measures the temperature dependence of the temperature difference between the sample and the reference material while changing the temperature of the sample and the reference material, and the functions of both TG and DTA TG-DT that we have
A device or TMA (Thermo-mec) that measures the deformation of a sample by applying a load to the sample while changing the temperature of the sample
hanical Analysis) devices and the like are known.

In these apparatuses, measurement is sometimes performed while flowing an inert gas such as N ₂ or Ar around the sample in order to prevent oxidation of the sample. Conventionally, when an inert gas is flowed in this way, one gas inlet and one gas outlet are provided in a sample chamber for storing a sample.
The measurement was performed while the inert gas introduced from the intake port was exhausted to the outside from the exhaust port.

[0004] In this case, however, the contaminant gas arrives at the sample by being sucked into the gas flow of the inert gas flowing around the sample, and as a result, accurate measurement may not be performed. In order to solve this problem, Japanese Patent Laid-Open No.
As disclosed in Japanese Patent No. 89552, by forming a divergent gas flow inside a sample chamber containing a sample, one gas flow is caused to flow around the sample, and the other gas flow is caused to flow away from the sample. A method of reducing the oxygen concentration around the sample while preventing the contaminant gas from reaching the sample can be considered.

The thermal analyzer disclosed in Japanese Patent Application Laid-Open No. 3-289552 is a device having a structure in which a mass spectrometer is attached to the gas exhaust side of a TG device. An orifice is provided in the first gas outlet, and the other gas outlet for guiding the other divided gas to the outside is in an open state without an orifice. Now, when trying to apply the gas splitting method disclosed in Japanese Patent Application Laid-Open No. 3-289552 to a general TG device or the like, that is, a TG device or the like having a structure to which no attached equipment such as a mass spectrometer is connected, it is usually Then, the following two methods can be considered.

One is a method in which both gas outlets of a first gas outlet and a second gas outlet are set to an open state without an orifice to divide the gas. However, in this method, the introduced gas flows to the first gas outlet or the second gas outlet, whichever is easier to flow, and cannot form a desired gas divergence. There is a problem that the oxygen concentration cannot be reduced to a desired level.

[0007] Another possible gas splitting method is to provide an orifice in a first gas outlet for guiding a gas passing through a sample to the outside, as in the technique disclosed in Japanese Patent Application Laid-Open No. 3-289552. By adjusting the flow rate of the gas flow by adjusting the orifice, a desired gas flow is formed. However, this method has a problem in that the internal pressure of the sample chamber fluctuates, for example, increases due to the adjustment of the orifice, and as a result, highly reliable measurement cannot be performed.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has a low oxygen content around a sample by forming a partial gas flow inside a sample chamber of a thermal analyzer. In a thermal analyzer that performs measurement by setting the concentration,
It is an object of the present invention to prevent a change in internal pressure from occurring inside a sample chamber and perform highly reliable measurement.

[0009]

In order to achieve the above-mentioned object, a thermal analyzer according to the present invention comprises a sample chamber in which a sample is placed, a first opening communicating with the sample chamber, and a gas chamber. And a gas supply port for supplying
A second opening provided on a side opposite to the first opening with respect to a position where the sample is arranged; and a gas conveying means connected to the second opening, wherein the first opening is open to the outside. It is characterized by being in a state.

[0010] According to the thermal analyzer having this configuration, the gas introduced from the gas supply port is divided into the first opening and the second opening to flow, so that a gas partial flow can be formed inside the sample chamber.
The gas shunt flowing through the first opening can place the sample in an environment of low oxygen concentration, while the gas shunt flowing through the second opening prevents the contaminant gas from approaching the sample.

At this time, the gas branch formed in the sample chamber is not due to the adjustment of the orifice, but to the suction of gas by the gas conveying means, and the first opening is set to an open state without an orifice. Since the inside of the sample chamber is always stably maintained at the same constant pressure as the external pressure, extremely stable and highly reproducible measurement results can be obtained.

In the above configuration, the gas supplied into the sample chamber may be an inert gas, for example, N ₂ , Ar or the like. In addition, TG equipment, DTA
A device, a TG-DTA device, a TMA device, and the like can be considered.

In general, a gas transfer means called a vacuum pump has a gas transfer capacity of several liters / min.
(Min) ~ about 60 l / min, desirably 40 l / mi
It is about n to 50 l / min. The gas conveying means used in the present invention is not a large-capacity vacuum pump as described above,
It is desirable that the gas conveying means has a smaller capacity. Specifically, 500 ml (milliliter) / min to 100
It is desirable that the gas conveying means has a gas conveying capacity of 0 ml / min.

The use of such a small-capacity gas transfer means is intended for forming a quiet gas flow in the sample chamber and for stably maintaining the internal pressure in the sample chamber. This is because it is desirable to keep the capacity to the minimum necessary without increasing the capacity. Such a small-volume gas conveying means is less likely to generate pulsation, and is therefore suitable for forming a quiet and stable gas flow.

In the thermal analyzer having the above-mentioned structure, it is desirable to provide a flow control means upstream of the gas transport means. In this way, the gas flow in the sample chamber can be adjusted to an appropriate flow. Further, in the thermal analyzer having the above configuration, it is desirable to provide a flow control means upstream of the gas supply port. In this way, the gas flow in the sample chamber can be adjusted to an appropriate flow. Further, the gas transport means may be provided both on the upstream side of the gas transport means and on the upstream side of the gas supply port. This makes it possible to more precisely adjust the state of the gas flow in the sample chamber.

In the thermal analyzer having the above-mentioned structure, the first flow rate control means disposed upstream of the gas transport means and the second flow rate control means disposed upstream of the gas supply port may include: It is desirable to include a valve that can be operated from the outside and a flow rate display unit that displays the flow rate so that it can be recognized from the outside. In this case, an appropriate gas flow can be formed in the sample chamber by an external operation.

Incidentally, gas flow meters are generally broadly classified into volume flow meters and mass flow meters. The volume flow meter is used in a state where each part of the flow meter is open to the atmosphere, that is, in a state where pressure is not applied to the inside of the flow meter.For example, a float type flow meter, a soap film flow meter, a wet gas meter, and the like are known. ing. Further, the mass flow meter detects the flow rate of gas by weight, and can define the same state even when the gas is compressed or the density is changed. This mass flow meter is sometimes called a mass flow meter. For example, an electromagnetic flow meter, an ultrasonic flow meter, a thermal flow meter, and the like are known.

The flow rate display section of the flow rate control means used in the present invention can be constituted by using a volume flow meter, a mass flow meter, or a flow meter having any other structure. For example, specifically, the upper end is wide and the lower end is narrow. The flow rate can be displayed by the tapered pipe and the moving element housed inside the tapered pipe. And in that case, regarding the first flow rate control means, the lower end side of the tapered pipe is connected to the second opening, and the valve is provided on the upper end side of the tapered pipe,
Preferably, the gas transport means is connected to the valve. Regarding the second flow control means, it is preferable that the valve is provided at a lower end side of the tapered pipe, a gas source is connected to the valve, and an upper end side of the tapered pipe is connected to the gas supply port. .

According to this configuration, both the first flow rate control means and the second flow rate control means are connected to the sample chamber, that is, the port on the side opposite to the valve which is open to the atmospheric pressure side.
In other words, the taper pipe functioning as the flow rate display unit is placed on the atmospheric pressure open side, not on the high pressure side of the valve. Therefore, the flow rate display using the taper pipe can be performed stably and accurately. Becomes

Next, in the thermal analyzer having the above structure, the gas transfer means has two gas transfer systems, and one gas transfer system takes in air from the first flow rate control means and exhausts it to the outside. It is preferable that one of the gas transfer systems takes in air from the atmosphere and exhausts the gas to the gas supply port, and the two gas transfer systems of the gas transfer means can be switched by an external operation.

With the above-described one gas transfer system that draws in air from the first flow rate control means and exhausts the gas to the outside, the gas in the sample chamber is sucked through the second opening connected to the first flow rate control means. An appropriate gas flow can be formed in the sample chamber. On the other hand, if one of the other gas transport systems described above that takes in air from the atmosphere and exhausts gas to the gas supply port of the sample chamber is used, air in the atmosphere can be forcibly sent into the sample chamber through the gas supply port.

The use of the above-described gas transfer system that takes in air from the atmosphere and exhausts gas to the gas supply port of the sample chamber enables, for example, thermal analysis measurement in an air atmosphere and so-called burn-in processing of the sample portion. . The thermal analysis measurement in an air atmosphere is a measurement method for performing a thermal analysis measurement on a sample while flowing air around the sample. The burn-off process is a process of cleaning the inside of the sample chamber by oxidizing carbon and the like attached to the walls and the like of the sample chamber and blowing it off by an air flow.

In the thermal analyzer, the sample chamber is often provided with some accessory chamber. For example, TG-D
In the case of a TA device, a balance room as an accessory room is attached to the sample room. Further, in a TG device or other devices, an accessory room storing some mechanism may be added to the sample chamber. In the thermal analyzer having the accessory chamber spatially connected to the sample chamber as described above, it is desirable to provide the second opening in the accessory chamber. In this way, the contaminated gas in the annex room can be efficiently guided to the second opening, whereby
Contaminant gas can be reliably prevented from approaching the sample. If the second opening is provided in the accessory chamber, that is, the balance chamber in the thermal analyzer having the balance chamber as the accessory chamber, the contaminated gas in the balance chamber can be reliably discharged to the outside of the sample chamber.

Next, the thermal analysis method according to the present invention comprises a sample chamber in which a sample is placed, a first opening communicating with the sample chamber, a gas supply port for supplying gas to the sample chamber, A second opening provided on a side opposite to the first opening with respect to a position where the first opening is disposed, and gas transfer means connected to the second opening, wherein the first opening is open to the outside. In a thermal analysis measurement method using a thermal analyzer, 50% or more of the gas supplied while supplying the gas to the gas supply port, preferably most of the supplied gas, more preferably supplied gas About 80% of the gas is sucked from the second opening by the gas transfer means and transferred to the outside, and the gas is supplied to the gas supply port after the first gas transfer step while supplying gas to the gas supply port. 5 of that gas
0% or less, preferably a small portion of the supplied gas, more preferably several tens of% of the supplied gas, more preferably about 20% of the supplied gas is sucked from the second opening by the gas conveying means. And a second gas transporting step of transporting the gas to the outside.

According to this thermal analysis measurement method, most of the contaminated gas can be reliably discharged from the second opening to the outside in the first gas transfer step, and the gas flowing toward the second opening in the subsequent second gas transfer step By suppressing the flow and supplying the suppressed gas to the first opening, that is, the sample, more fresh gas can be supplied to the sample to reduce the oxygen concentration around the sample.

Next, the gas flow unit according to the present invention is assembled in a thermal analyzer having two gas supply ports, which are connected to the sample chamber, and a second opening which is also connected to the sample chamber. This is a gas flow unit that can easily configure the thermal analysis device. Specifically, the gas flow unit according to the present invention includes an intake port that opens to the outside, a first flow rate control unit that is connected to the intake port, and that can adjust a flow rate of gas flowing through the intake port, (1) a gas transfer means connected to the flow control means for transferring gas through the first flow control means, an exhaust port connected to the gas transfer means and opening to the outside,
A gas intake for taking in gas, a second flow control means connected to the gas intake for controlling a flow rate of gas flowing through the gas intake, and an external opening connected to the second flow control means And a gas supply port.

According to this gas flow unit, the intake port is connected to the second opening of the thermal analyzer, and the gas supply port is connected to the gas supply port of the thermal analyzer. The thermal analyzer can be easily configured. As described above, the thermal analyzer configured as described above can perform a thermal analysis measurement under a low oxygen concentration under an extremely stable internal pressure.

In the gas flow unit having the above structure,
It is preferable that the first flow control means and the second flow control means have a valve which can be operated from the outside and a flow rate display section which displays the flow rate so that the flow rate can be recognized from the outside. In this case, when the present gas flow unit is attached to a thermal analyzer, an appropriate gas flow can be formed in the sample chamber by an operation from the outside.

Further, the above-mentioned flow rate display section comprises a volume flow meter,
Although it can be configured using a mass flow meter or a flow meter having another structure, for example, specifically, the flow rate is indicated by a tapered pipe having a wide upper end and a narrow lower end, and a mover housed inside the tapered pipe. It can be structured. In that case, with respect to the first flow rate control means, the lower end side of the tapered pipe is connected to the second opening, the valve is provided at the upper end side of the tapered pipe, and the valve is provided with the gas transfer means. It is desirable to be connected. Regarding the second flow control means, it is preferable that the valve is provided at a lower end side of the tapered pipe, a gas source is connected to the valve, and an upper end side of the tapered pipe is connected to the gas supply port. .

According to this configuration, in both the first flow rate control means and the second flow rate control means, the port connected to the sample chamber, that is, the atmospheric pressure open side is the port on the side opposite to the valve.
In other words, the taper pipe functioning as the flow rate display unit is placed on the atmospheric pressure open side, not on the high pressure side of the valve. Therefore, the flow rate display using the taper pipe can be performed stably and accurately. Becomes It should be noted that the flow rate display unit may be configured using a mass flow meter, and in this case, the connection form of the mass flow meter to the sample chamber can be set quite freely.

Next, in the gas flow unit having the above structure, an air outlet opening to the outside is further provided, and the gas conveying means has two gas conveying systems, and one gas conveying system is provided with the first flow rate. Intake from the control means and exhaust to the exhaust port, another one gas transport system inhales from the atmosphere and exhausts to the air outlet, two gas transport systems of the gas transport means are external Desirably, it can be switched by operation.

If the above-mentioned one gas transfer system which takes in air from the first flow rate control means and exhausts the gas to the exhaust port is used, the gas in the sample chamber passes through the second opening on the sample chamber side connected to the first flow rate control means. By aspirating, an appropriate gas flow can be formed in the sample chamber. On the other hand, by connecting the air outlet to the gas supply port on the sample chamber side and using the other one of the gas transfer systems described above, which draws in air from the atmosphere and exhausts the air to the air outlet, the air in the atmosphere can be gaseous. It can be forcibly fed into the sample chamber through the supply port. Thus, it is possible to perform a thermal analysis measurement on the sample in a state where the sample is placed in the air flow, or to perform a so-called burn-out process of the sample portion.

[0033]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a case where the present invention is applied to a TG-DTA device will be described as an example. FIG. 1 is a side sectional view showing one embodiment of a thermal analysis device, a thermal analysis measurement method, and a gas flow unit according to the present invention.

The thermal analyzer 1 shown here comprises a sample chamber 2 and
A balance room 3 as an auxiliary room, and a sample room 2 through the balance room 3
And a gas flow unit 4 connected thereto. A pair of weighing mechanisms 6a and 6b are provided in the weighing chamber 3, and sample dishes 8a and 8b provided at the tips of weighing rods 7a and 7b extending from the weighing mechanisms 6a and 6b are connected to the sample chamber 2.
It is arranged inside. One of the sample dishes 8a and 8b, for example, the sample dish 8a contains a sample S to be measured, and the other, for example, the sample dish 8b contains a reference material R, which is a thermally stable substance.

A heater 11 is provided around the sample dishes 8a and 8b via a protective tube 9. A temperature controller 12 is connected to the heater 11. Temperature controller 1
2 energizes the heater 11 in accordance with a predetermined program, whereby the heater 11 generates heat in a predetermined change state. The protection tube 9 prevents the heater 11 from being damaged by, for example, gas emitted from the sample S or the like.

The protection tube 9 has an opening 9a at the tip thereof, and the opening 9a is formed with a first opening O1 formed at the tip of the sample chamber 2.
Communicate with Also, the sample chamber 2 connected to the balance chamber 3
Is provided with a gas supply port 13.

The first opening O1 with respect to the sample dishes 8a and 8b
A second opening O2 and a gas passage port 14 are provided in the end wall 3a of the balance chamber 3 located on the opposite side to the second opening O2. Gas port 14
Is a relay pipe 16 disposed inside or outside the balance chamber 3.
Connected to the gas supply port 13. With this configuration, the gas supply port 13 enters the sample chamber 2 at a position farther from the first opening O1 than the sample dishes 8a and 8b and closer to the sample dishes 8a and 8b than the second opening O2. Supply gas.

In this embodiment, since the sample chamber 2 is provided with the balance chamber 3 as an accessory chamber, the balance chamber 3 is provided with the second opening O2. In the case where the thermal analyzer is constituted only by the sample chamber 2, the second opening 2 is provided in the sample chamber 2.

The balance mechanisms 6a and 6 stored in the balance chamber 3
The TG measuring unit 17 is connected to b. This TG measurement unit 1
Numeral 7 measures the relative weight change occurring between the sample S and the reference substance R, and any structure can be adopted as long as the action is achieved.

The temperature measuring points Pa are located near the sample dishes 8a and 8b.
And Pb are set, and the temperature measuring points Pa and Pb are set to D.
The TA measuring unit 18 is connected. The DTA measuring section 18 measures a thermal change of the sample S by measuring a temperature difference generated between the sample S and the reference substance R, and has an arbitrary structure as long as the action is achieved. Can be adopted.

As shown in FIG. 2, the gas flow unit 4 has an intake port 21 opening to the outside and a first flow meter 2 as first flow control means connected to the intake port 21.
2, a gas transport pump 23 as a gas transport means connected to the first flow meter 22, an exhaust port 24 connected to the gas transport pump 23 and opening to the outside,
A gas inlet 26 for taking in a gas, a second flow meter 27 as second flow control means connected to the gas inlet 26, and a gas supply port connected to the second flow meter 27 and opening to the outside 28. Sign 3
Reference numeral 7 denotes an electrical connection terminal for receiving power supply from the AC power supply 38.

The gas transfer pump 23 has two gas transfer systems 2
9a and 29b, and any one of these gas transport systems can be selected by operating the changeover switch 48 of the operation switch 31. The exhaust port 32 of the first flow meter 22 is connected to the intake port 33a of the first gas transport system 29a, and the exhaust port 24 is connected to the exhaust port 34a of the first gas transport system 29a. Intake port 33b of second gas transfer system 29b of gas transfer pump 23
Is open to the outside, that is, the atmosphere, and its exhaust port 34b
Is connected to an air outlet 36 that opens to the outside.

The gas transfer pump 23 includes the first gas transfer system 2
9a is selected, the first flow meter 22
The air is sucked through the exhaust port and the air is exhausted to the outside through the exhaust port 24. When the second gas transfer system 29b is selected, atmospheric air is sucked from the intake port 33b, and the air is discharged to the outside from the air outlet 36. The gas transfer pump 23 has a gas transfer capacity of about 500 ml / min to 1000 ml / min.

Generally, a so-called vacuum pump used to evacuate the target space is a few l / min to 50 l / min.
min gas transfer capacity, and it can be seen from this that the gas transfer pump 2 used in the present embodiment.
It can be said that 3 is a small pump having a small gas carrying capacity.

The first flow meter 22 and the second flow meter 27 have needle valves 42a, 42b which can be operated from outside by means of knobs 41a, 41b, and flow rate display sections 43a, 43b for displaying the gas flow rate to the outside. The flow rate display units 43a and 43b are configured by placing the moving element 46 in a tapered tube 44 having a wide upper end and a narrow lower end. A scale is provided on the surface of the tapered tube 44, and when the moving member 46 moves in accordance with the flow of gas flowing through the tapered tube 44, the position of the moving member 46 is read by the scale of the tapered tube 44, whereby the tapered tube 44 is read. The flow rate of the flowing gas can be known.

FIG. 3 shows the external appearance of the gas flow unit 4. As shown in FIG.
The flow meter 27 is provided on the front panel 4a of the gas flow unit 4, and its knobs 41a and 41b can be operated from outside. The scale of the tapered tube 44 can be visually confirmed from the outside. Reference numeral 31 denotes an operation switch. Specifically, a power switch 47 for turning on / off the power and a gas transfer system of the gas transfer pump 23 are connected to the first gas transfer system 29a and the second gas transfer system 29a.
A gas transport system changeover switch 48 for switching between the gas transport system 29b and the gas transport system 29b is included.

Hereinafter, the operation of the thermal analyzer of the present embodiment having the above configuration will be described. First, before starting the measurement, in FIG. 1, a pre-measurement process for setting the inside of the sample chamber 2 to a low oxygen concentration suitable for the thermal analysis measurement is performed as follows. The inlet 21 of the gas flow unit 4 and the second opening O2 of the balance chamber 3 are connected to each other directly using the connecting pipe 49. In addition, the gas supply port 28 of the gas flow unit 4 and the gas passage port 14 of the balance chamber 3 are connected to each other directly using the connecting pipe 51. Further, a gas cylinder 53 as a gas source is connected to the gas intake port 26 by using a connecting pipe 52. An inert gas such as N ₂ , A
r and the like are stored.

Next, in FIG. 2, the power supply switch 47 of the operation switch 31 is turned on to start the gas transport pump 23, and the gas transport system changeover switch 48 is switched to the first gas transport system 29a, that is, the normal gas flow system. set. Further, the gas cylinder 53 is opened to set the gas supply state, and the knob 41b of the second flow meter 27 is adjusted in FIG. 2 to flow a predetermined amount of gas, for example, 1 l. At the same time, the knob 41a of the first flow meter 22 is adjusted to flow a predetermined amount of gas, for example, 800 ml.

As described above, the sample chamber 2 and the balance chamber 3 shown in FIG.
For example, 1 l of inert gas is supplied from the gas supply port 13 located between the sample S and the second opening O2, and for example, 800 ml of the 1 l of inert gas passes through the second opening O2. Guided to flow unit 4,
Further, the gas is exhausted from the exhaust port 24 to the outside by the gas transport pump 23. On the other hand, the remaining 200 ml is exhausted to the outside through the first opening O1 in FIG. Since the first opening O1 is open to the outside, the sample chamber 2 is always the same as the outside pressure.
Usually, it is maintained at atmospheric pressure, that is, 1 atm.

It should be noted that the above gas transport amount, that is, 800
The figures of ml and 200 ml are only examples,
In actual measurement, various values are set according to the volume of the sample chamber and other conditions.

As described above, for example, 1 l of the supplied inert gas is flowed, for example, 800 ml in a direction away from the sample S, and is passed through the sample S, for example, 200 m into the first opening O1.
The inert gas splitting process of flowing 1 is continuously performed, for example, for about 20 to about 30 minutes. Thus, the contaminated gas present in the relatively large balance chamber 3 can be reliably discharged to the outside without flowing toward the sample S. In addition, the time of about 20 minutes to about 30 minutes is only an example,
In the actual measurement, another appropriate time can be set as needed.

Next, referring to FIG.
The knob 41a is adjusted to adjust the flow rate of the gas flowing through the flow meter from the above-mentioned 800 ml to 200 m, for example.
Switch to l. Thereby, for example, 200 ml of the branch flow of the gas relating to the sample chamber 2 and the balance chamber 3 of FIG. 1 flows to the second opening O2 separated from the sample S, and 800 ml flows to the first opening O1 through the sample S. In addition, 800m
The gas transport amounts of 1 and 200 ml are merely examples, and in actual measurement, various values are set according to the volume of the sample chamber and other conditions.

For example, the split state is changed from about 30 minutes to about 40 minutes.
If it is continued for a minute, the oxygen concentration in the sample chamber 2 is stabilized to, for example, several tens ppm or less. This oxygen concentration can be measured by an oxygen concentration meter or the like. This residual oxygen concentration is about 10 to 20 times that of a conventional apparatus having a structure in which an inert gas is simply supplied from one gas supply port and an inert gas is simply discharged from one gas outlet to the outside. It is a low value. When N ₂ is used as an inert gas, the concentration of N ₂ is several tens of p.
pm or less. The concentration of the Ar By using Ar as the inert gas is at a concentration slightly higher than in the case of N _2. Note that the above time of about 30 minutes to about 40 minutes is merely an example, and other appropriate times can be set as needed in actual measurement.

After the oxygen concentration in the sample chamber 2 is stabilized, the DTA measurement unit 18 and the TG measurement are performed while the temperature of the sample S and the reference substance R are adjusted by adjusting the heat generation of the heater 11 by the temperature controller 12. A thermal analysis measurement can be performed by the unit 17. Specifically, the temperature difference between the sample S and the reference substance R is detected by the DTA measuring unit 18 while the temperature of the sample S and the reference substance R is changed by the heater 11 according to a predetermined program. Detect thermal changes. On the other hand, the TG measuring unit 17 measures the weight change of the sample S, which changes in temperature in the same manner as the weight change of the reference substance R, which changes in temperature.
7 to detect.

During the above measurement, a large amount of the inert gas flows in the direction of the first opening O1 as 800 ml, and the flow in the direction of the second opening O2 is suppressed as small as 200 ml. As described above, a large amount of inert gas is supplied to the first opening O during the measurement.
By flowing in one direction, fresh gas can always be supplied around the sample S.

In this embodiment, the inert gas introduced from the gas passage 14 is supplied to the gas supply port 13, that is, the boundary between the sample chamber 2 and the balance chamber 3, that is, the boundary between the electric furnace unit and the balance chamber 3, that is, the sample. S is introduced from between S and the second opening O2, and the gas transfer pump 23 is used to balance the amount of gas discharged from the exhaust port 24 and the amount of gas discharged from the second opening O2.
To prevent the residual oxygen present in the balance chamber 3 from entering the sample chamber 2 in the electric furnace. During the measurement, the first opening O1 is always open to the outside, that is, to the atmosphere, so that the internal pressure of the sample chamber 2 is maintained in a stable state without fluctuation. High thermal analysis measurement results can be obtained.

When the above-described thermal analysis measurement is repeatedly performed, the inside of the protection tube 9 in the sample chamber 2 becomes dirty. Therefore, a cleaning process is required in a timely manner. In that case, a so-called burn-off process is performed as follows.

That is, first, in FIG. 1, the connecting pipe 51 is removed from the gas supply port 14 to release the inert gas supply system. Then, the air outlet 36, that is, the exhaust port 34b of the second gas transport system 29b of the gas transport pump 23 shown in FIG. Then, the gas transport system changeover switch 48 in FIG. 2 is switched to the second gas transport system 29b side, and the gas transport pump 23 is operated to take in external air from the intake port 33b of the second gas transport system 29b. The gas is supplied to the sample chamber 2 through the gas supply port 13 in FIG. The sent air flows inside the protection tube 9 and is exhausted to the outside through the first opening O1. As described above, for example, carbon or the like adhering to the inside of the protection tube 9 is oxidized by the air flowing through the inside of the protection tube 9 and blown out to the outside, whereby the inside of the protection tube 9 is cleaned.

In the case where the thermal analysis measurement is performed with the sample placed in an air flow atmosphere, the measurement can be performed in the same procedure as described above using the second gas transport system 29b.

In the present embodiment described above, as shown in FIGS. 2 and 3, the 1-atmosphere open side of the first flow meter 22 and the second flow meter 27, that is, the side connected to the balance chamber 3 is a needle valve. Since it is connected to the port on the opposite side of 42a and 42b, the flow rate display of the flow rate display sections 43a and 43b composed of the tapered tube 44 and the moving element 46 becomes accurate. In addition, an accurate display can be realized using a mass flow meter that performs display based on the mass flow rate, separately from these flow meters.

The gas transfer pump 23 has a small transfer capacity of 500 ml / min to 1000 ml / min. It is not necessary to use a large-capacity pump such as a so-called vacuum pump. The flow unit 4 can be made extremely simple, small and inexpensive. It is desirable that the gas transport pump has as little pulsation as possible, and preferably has no pulsation. This is for forming a stable gas flow in the sample chamber 2. In addition, when an appropriate branch flow can be realized by using a large-capacity pump such as a vacuum pump, such a pump may be used.

Further, in this embodiment, the gas flow unit 4 is a single unit, and the gas flow unit 4 is set in the sample chamber 2 or the balance chamber 3 to set the inside of the sample chamber 2 to a low oxygen concentration. Is very convenient.

Further, the state of the split flow of the inert gas formed in the sample chamber 2 can be freely set by adjusting the flow rate by the first flow meter 22 and the second flow meter 27. 4 can be applied to various thermal analyzers. That is, versatility is very high.

As described above, the present invention has been described with reference to the preferred embodiments. However, the present invention is not limited to the embodiments, and can be variously modified within the scope of the invention described in the claims.

For example, in the above embodiment, the present invention is applied to the TG-DTA apparatus, but the present invention applies to any other thermal analysis apparatus which needs to form a gas flow around the sample.
For example, the present invention can be applied to a TG device, a DTA device, a TMA device, and the like. Also, any room other than the balance room can be attached as the attachment room.

[0066]

As described above, according to the thermal analysis apparatus and the thermal analysis measurement method of the present invention, the gas introduced from the gas supply port is divided into the first opening and the second opening to flow. In addition, a gas divergence can be formed inside the sample chamber. And
The gas shunt flowing through the first opening can place the sample in a low oxygen concentration environment, while the gas shunt flowing through the second opening can prevent contaminant gases from approaching the sample.

At this time, the gas shunt formed in the sample chamber is not caused by the adjustment of the orifice, but by the suction of the gas by the gas transfer means. Further, the first opening is set to the open state without the orifice. The inside of the sample chamber is always stably maintained at the same constant pressure as the outside air pressure, so that extremely stable and highly reproducible measurement results can be obtained.

Further, according to the gas flow unit of the present invention, by connecting the gas flow unit to a thermal analysis device having an arbitrary configuration provided with a gas supply port and a second opening, a desired desired gas flow can be easily sampled. It can be formed indoors. Further, since the gas flow unit is a single unit device, it can be carried around, which is very convenient.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing one embodiment of a thermal analyzer according to the present invention.

FIG. 2 is a diagram showing an internal structure of a gas flow unit which is a main device of FIG.

FIG. 3 is an external perspective view of the gas flow unit shown in FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Thermal analyzer 2 Sample room 3 Balance room (accessory room) 4 Gas flow unit 6a, 6b Balance mechanism 8a, 8b Sample dish 9 Protective tube 11 Heater 13 Gas supply port 14 Gas passage 16 Relay pipe 21 Intake port 22 First Flow meter (first flow control means) 23 Gas transfer pump (gas transfer means) 24 Exhaust port 26 Gas intake 27 Second flow meter (Second flow control means) 28 Gas supply ports 29a, 29b Gas transfer system 36 Air intake Outlets 41a, 41b Knobs 42a, 42b Needle valves 43a, 43b Flow rate display unit 44 Tapered tube 46 Mover O1 First opening O2 Second opening Pa, Pb Temperature measuring point R Reference material S Sample

Claims (4)

[Claims] 1. A thermal analysis apparatus having a sample chamber in which a sample is arranged, a first opening communicating with the sample chamber, and a gas supply port for supplying gas to the sample chamber. Having a second opening provided on the opposite side of the first opening, and gas conveying means connected to the second opening, wherein the first opening is open to the outside. Thermal analyzer. 2. The apparatus according to claim 1, further comprising a flow control unit disposed upstream of the gas conveying unit, wherein the gas conveying unit has two gas conveying systems, and one gas conveying system is Intake from the flow control means and exhaust to the outside, and another one gas transport system inhales from the atmosphere and exhausts to the gas supply port. Two gas transport systems of the gas transport means operate from outside. A thermal analysis apparatus characterized in that the thermal analysis apparatus can be switched by a switch. 3. A sample chamber in which a sample is arranged, a first opening communicating with the sample chamber, a gas supply port for supplying gas to the sample chamber, and a position of the sample in which the sample is arranged. A thermoanalytical measurement method using a thermoanalytical device having a second opening provided on the opposite side, and gas conveying means connected to the second opening, wherein the first opening is open to the outside. A first gas transporting step in which 50% or more of the gas supplied while supplying gas to the gas supply port is sucked from the second opening by the gas transporting means and transported to the outside; After the step, a second gas transfer step of sucking the gas supplied to the gas supply port by 50% or less of the supplied gas from the second opening by the gas transfer means and transferring the gas to the outside. Characteristic thermal analysis measurement method. 4. An air intake opening to the outside, a first flow control means connected to the air intake and capable of adjusting a flow rate of gas flowing through the air intake, and connected to the first flow control means. A gas transfer means for transferring gas through the first flow control means, an exhaust port connected to the gas transfer means and opening to the outside, a gas intake for taking in gas, and connected to the gas intake. A gas flow unit comprising: a second flow rate control means capable of adjusting a flow rate of a gas flowing through the gas intake port; and a gas supply port connected to the second flow rate control means and opened to the outside.