WO2025062997A1 - Analysis device and analysis method - Google Patents

Abstract

This analysis device is provided with: an impulse heating furnace or a high-frequency heating furnace that heats a sample to generate a sample gas containing elements that constitute the sample; a suction flow path that sucks the sample gas generated in the impulse heating furnace or the high-frequency heating furnace by means of a suction unit; and an element detecting unit that is provided in the suction flow path to detect the elements contained in the sample gas.

Description

Analytical device and analytical method

The present invention relates to an analysis device and an analysis method.

As an example of a conventional analytical device, as shown in Patent Document 1, there is one that analyzes the elements contained in a sample by heating a sample contained in a crucible while introducing a carrier gas, extracting the sample gas generated during the process together with the carrier gas, and detecting the elements contained in the sample gas with a detector.

JP 2022-65206 A

In the above analytical equipment, carrier gas needs to be continuously flowed to transport the sample gas to the detector, so a large amount of carrier gas needs to be used, resulting in high running costs.

The present invention was made in consideration of the above-mentioned problems, and its main objective is to eliminate the need for a carrier gas to flow the sample gas in an analytical device that detects elements contained in the sample gas generated when the sample is heated and analyzes the elements contained in the sample.

In other words, the analytical device according to the present invention is characterized by comprising an impulse heating furnace or high-frequency heating furnace that heats a sample and generates a sample gas containing the elements that constitute the sample, an aspiration flow path that draws in the sample gas generated in the impulse heating furnace or high-frequency heating furnace using an aspiration unit, and an element detection unit that is provided in the aspiration flow path and detects the elements contained in the sample gas.

In such an analytical device, the suction section draws in the sample gas, causing it to flow through the suction flow path, making it unnecessary to use carrier gas to carry the sample gas. As a result, it is possible to reduce the running costs associated with using carrier gas.

The analytical device preferably further comprises a valve provided in the suction flow path and a valve control unit that controls the valve, the suction unit being provided downstream of the valve in the suction flow path, the valve control unit closing the valve when the impulse heating furnace or the high-frequency heating furnace is heating the sample, and opening the valve when the pressure of the sample gas reaches or exceeds a predetermined value, and the suction unit sucking in the sample gas when the valve is opened.

In this configuration, when the sample is heated with the valve closed, sample gas is generated in the impulse heating furnace or high-frequency heating furnace, creating a pressure difference between the upstream and downstream sides of the valve. Compared to a configuration without a valve, after the valve is opened, the sample gas can be passed through the element detection section all at once, thereby improving the detection accuracy, especially for sample gas generated from low-concentration samples.
In addition, since the valve control unit opens the valve when the pressure of the sample gas reaches a predetermined level or higher, the time during which the element detection unit detects the elements contained in the sample gas can be adjusted, and the element detection unit can accurately detect the elements contained in the sample gas for both high-concentration samples and low-concentration samples.

Specific examples of the valve control unit include a valve that opens the valve when the pressure of the sample gas inside the impulse heating furnace or the high-frequency heating furnace is equal to or greater than a predetermined value, or when the difference between the pressure upstream and downstream of the valve is equal to or greater than a predetermined value.

A specific embodiment of the valve control unit is one that further includes a predetermined value receiving unit that receives a predetermined value for the pressure of the sample gas set by the user.

The valve control unit may further include a sample type reception unit that receives the type of sample input by a user, a sample gas amount storage unit that associates and stores the type of sample with the amount of sample gas generated from the sample, and a predetermined value setting unit that, when the sample type reception unit receives the type of sample, obtains the amount of sample gas associated with the type of sample from the storage unit and sets a predetermined value of the sample gas based on the amount of sample gas obtained from the storage unit.

With this configuration, even if a user is not able to set a specific value for the sample gas due to their level of skill, the user only needs to input the type of sample, and can set the specific value for the sample gas regardless of their level of skill.

The valve control unit may control the opening of the valve based on the pressure of the sample gas.

With this configuration, the pressure of the sample gas flowing through the suction flow path can be changed by controlling the opening of the valve. By changing the pressure of the sample gas, particularly in high-concentration or low-concentration sample gas, it is possible to prevent a decrease in detection accuracy caused by the signal detected by the element detection unit becoming extremely large or small.

The suction unit is a pump, the analysis device further includes a rotation speed acquisition unit that acquires the rotation speed of the pump, and the valve control unit controls the valve based on the rotation speed of the pump acquired by the rotation speed acquisition unit.

With this configuration, for example, by controlling the valve opening based on the vacuum state of the suction flow path, the element detection unit can accurately detect elements contained in the sample gas for both high-concentration and low-concentration samples.

The valve is preferably provided upstream of the suction flow path from the element detection unit.

In this configuration, the sample gas generated in the impulse heating furnace or high-frequency heating furnace flows into the element detection section when the valve is opened, making it easier for the element detection section to detect elements contained in the sample gas compared to a configuration in which the sample gas generated in the heating furnace flows directly into the element detection section.

A specific example of the suction unit is a pump that is provided downstream of the suction flow path from the element detection unit.

In this configuration, the suction unit is provided downstream of the element detection unit in the suction flow path, so that exhaust gas discharged from the suction unit does not flow into the element detection unit, and as a result, the element detection unit can detect elements contained in the sample gas with high accuracy.
Moreover, by adjusting the output of the pump, the amount of sample gas sucked into the suction passage can be adjusted.

　In conventional non-dispersive infrared gas analyzers (hereinafter referred to as NDIR), it is necessary to keep the carrier gas flowing in order to flow the sample gas, but it is preferable that at least one of the element detection units of the present invention is a non-dispersive infrared gas analyzer.

With this configuration, when detecting elements contained in a sample gas using NDIR, it is possible to eliminate the need for a carrier gas, which was previously essential for element detection using NDIR.

The analysis method is also characterized in that a sample is heated to generate a sample gas containing elements constituting the sample in an impulse heating furnace or a high-frequency heating furnace, the sample gas generated in the impulse heating furnace or the high-frequency heating furnace is sucked in by an suction unit provided in the suction flow path, and the elements contained in the sample gas are detected.

With this configuration, it is possible to obtain the same effects as the above-mentioned analysis device.

The present invention, configured in this way, can eliminate the need for a carrier gas in an analytical device that detects elements contained in a sample gas generated when a sample is heated and analyzes the elements contained in the sample.

1 is a schematic diagram showing an analysis device according to a first embodiment of the present invention. FIG. 4 is a schematic diagram showing an analysis device according to a second embodiment of the present invention. FIG. 13 is a schematic diagram showing functional blocks of a valve control unit in another embodiment of the present invention. FIG. 4 is a schematic diagram showing an analysis device according to another embodiment of the present invention.

First Embodiment
The following describes an analysis device 100 according to a first embodiment of the present invention with reference to the drawings. Note that in any of the drawings shown below, some parts may be omitted or exaggerated in schematic form for ease of understanding. Identical components are given the same reference numerals and descriptions thereof will be omitted as appropriate.

As shown in FIG. 1, the analytical device 100 according to this embodiment analyzes the elements contained in a sample by heating the sample contained in a crucible R and detecting the elements contained in a sample gas that contains the elements that make up the sample. In this embodiment, the crucible R is a graphite crucible.

Specifically, as shown in FIG. 1, the analytical device 100 includes an impulse heating furnace 1 for heating a sample, a suction flow path L for suctioning gas generated in the impulse heating furnace 1 by a suction unit 8, a dust filter 2, and a valve 3. Each part will be described below.

The impulse heating furnace 1 is used to place a crucible R containing a sample, and to generate a sample gas by heating the sample in the crucible R. In this embodiment, the impulse heating furnace 1 heats the crucible R before the sample is placed in the crucible R, which generates exhaust gas from the crucible R. In this embodiment, a hopper (not shown) is provided at the top of the impulse heating furnace 1 to introduce the sample into the crucible R.

The suction flow path L has an outlet suction flow path L1 through which the gas generated in the impulse heating furnace 1 is drawn out, a sample gas suction flow path L2 through which sample gas from the gas generated in the impulse heating furnace 1 flows, and an exhaust gas suction flow path L3 through which exhaust gas from the gas generated in the impulse heating furnace 1 flows.

The dust filter 2 filters out soot and other particles contained in the gas discharged from the impulse heating furnace 1, removing dust.

The valve 3 opens and closes the suction flow passage L. Specifically, the valve 3 has an upstream valve 31 provided upstream of the outlet suction flow passage L1 from the dust filter 2, and a downstream valve 32 provided downstream of the outlet suction flow passage L1 from the dust filter 2. In this embodiment, the upstream valve 31 opens and closes the outlet suction flow passage L1. The downstream valve 32 is a so-called three-way valve, and opens and closes the sample gas suction flow passage L2 and the exhaust gas suction flow passage L3.

In this embodiment, the valve 3 is controlled by the valve control unit C. Here, the valve control unit C is a so-called computer equipped with a CPU, memory, A/D converter, etc., and controls the valve 3 by the CPU and peripheral devices working together in accordance with a program stored in a specified area of the memory.

Specifically, the valve control unit C includes a predetermined value receiving unit C1 that receives a predetermined value of the sample gas input by the user, a measured pressure acquiring unit C2 that acquires the gas pressure measured by a pressure sensor (not shown) provided upstream of the upstream valve 31, and an opening/closing control unit C3 that controls the opening/closing of the upstream valve 31 and the downstream valve 32 based on the predetermined value of the sample gas and the gas pressure measured by the pressure sensor. Note that the pressure inside the impulse heating furnace 1 is not limited to a pressure sensor provided upstream of the upstream valve 31, but may be a differential pressure gauge that measures the pressure difference upstream and downstream of the upstream valve 31.

The sample gas suction flow path L2 is provided with an oxidizer 4 that oxidizes the sample gas, an element detection unit 5 that detects elements contained in the sample gas, a removal unit 6 that removes components contained in the sample gas, and a flow measurement unit 7 that measures the flow rate of the sample gas. The configuration of each unit provided in the sample gas suction flow path L2 is described below.

The oxidizer 4 is provided downstream of the sample gas suction flow path L2 from a CO detector 51 (described later) and oxidizes CO contained in the sample gas to _CO2 . The oxidation catalyst constituting the oxidizer 4 is, for example, a platinum catalyst, which is heated to about 700° C. The platinum catalyst can be heated by a heating resistor, for example.

The element detection unit 5 is composed of a CO detection unit 51, a _CO2 detection unit 52, an _H2O detection unit 53, and an _N2 detection unit 54. The CO detection unit 51, the _CO2 detection unit 52, the _H2O detection unit 53, and the _N2 detection unit 54 are provided in this order from the upstream side of the sample gas suction flow path L2.

The CO detection unit 51 detects CO (carbon monoxide) contained in the mixed gas that has passed through the dust filter 2 and measures its concentration. In this embodiment, the CO detection unit 51 is an NDIR (non-dispersive infrared gas analyzer). Due to its measurement accuracy, this CO detection unit 51 operates effectively when the oxygen contained inside the sample is at a high concentration. Specifically, it is preferable for the CO detection unit 51 to measure CO of 150 ppm or more.

The _CO2 detector 52 detects _CO2 (carbon dioxide) in the sample gas that has passed through the oxidation device 4 and measures its concentration. In this embodiment, the _CO2 detector 52 is an NDIR. From the viewpoint of measurement accuracy, the _CO2 detector 52 operates effectively when the oxygen contained in the sample is at a low concentration (for example, less than 150 ppm).

The _H2O detector 53 detects _H2O (water vapor) in the sample gas that has passed through the _CO2 detector 52 and measures its concentration. In this embodiment, the _H2O detector 53 is an NDIR. The sample gas suction flow path L2 from the oxidizer 4 to the _H2O detector 53 is configured to keep the temperature of the sample gas at 100°C or higher and to keep _H2O in a water vapor state. In this way, measurement errors due to condensation are prevented from occurring in the _H2O detector 53.

The _N2 detector 54 detects _N2 (nitrogen) in the sample gas that has passed through the _H2O detector 53 and the remover 6 described below, and measures the concentration of N2. In this embodiment, the _N2 detector 54 is a thermal conductivity detector (TCD).

The removal unit 6 adsorbs and removes _CO2 and _H2O from the sample gas. In this embodiment, the removal unit 6 has a CO2 removal unit 61 that removes _CO2 from the sample gas, and _{an H2O} removal unit 62 that removes _H2O from the sample gas. The _CO2 removal unit 61 and the _H2O removal unit 62 are made of an adsorbent, and the material of the adsorbent is, for example, a zeolite molecular sieve, silica gel, activated carbon, or ascarite.

The flow rate measuring unit 7 is a flow rate sensor that measures the flow rate of the sample gas that has passed through the N ₂ detection unit 54 .

The suction unit 8 sucks in the sample gas generated in the impulse heating furnace 1 and directs the sample gas into the sample gas suction flow path L2. In this embodiment, the suction unit 8 also sucks in the exhaust gas generated in the impulse heating furnace 1 and directs the exhaust gas into the exhaust gas suction flow path L3.

Specifically, the suction unit 8 is provided downstream of the element detection unit 5 in the sample gas suction flow path L2, and in this embodiment, the suction unit 8 is provided downstream of the flow rate measurement unit 7 in the sample gas suction flow path L2. Also, in this embodiment, the suction unit 8 is a pump. Specifically, the suction unit 8, which is a pump, sucks in the sample gas or exhaust gas and exhausts the sucked sample gas or exhaust gas outside the analysis device 100.

<Analysis method>
An analysis method using the analysis device 100 in this embodiment will be described below.

The user places a crucible R inside the impulse heating furnace 1. The user also places a sample in a hopper provided at the top of the impulse heating furnace 1 and seals the top of the impulse heating furnace 1. The specified value receiving unit C1 then receives, through input from the user, the specified value of the pressure of the sample gas when the valve control unit C opens the upstream valve 31.

Next, the upstream valve 31 is opened by the opening/closing control unit C3. The opening/closing control unit C3 also causes the downstream valve 32 to open the exhaust gas suction passage L3 and close the sample gas suction passage L2. The suction unit 8 is then started and the impulse heating furnace 1 heats the crucible R. As a result, exhaust gas from the crucible R is exhausted from the impulse heating furnace 1 through the outlet suction passage L1 and the exhaust gas suction passage L3. After a predetermined time has passed, the suction by the suction unit 8 creates a vacuum in the impulse heating furnace 1, outlet suction passage L1, sample gas suction passage L2, and exhaust gas suction passage L3.

Next, the opening/closing control unit C3 closes the upstream valve 31, sealing the impulse heating furnace 1. The sample is then loaded from the hopper into the crucible R. After the sample is loaded into the crucible R, the impulse heating furnace 1 heats the sample. In the impulse heating furnace 1, sample gas is generated from the sample, and the pressure inside the impulse heating furnace 1 increases. While the impulse heating furnace 1 is heating the sample, the suction unit 8 draws suction into the sample gas suction passage L2 and the exhaust gas suction passage L3, creating a vacuum state.

When the pressure measured by the pressure sensor installed upstream of the upstream valve 31 reaches a predetermined value or more, the opening/closing control unit C3 opens the upstream valve 31. The opening/closing control unit C3 also causes the downstream valve 32 to close the exhaust gas suction flow path L3 and open the sample gas suction flow path L2. In the impulse heating furnace 1, the pressure increases due to the generation of sample gas, and since the sample gas suction flow path L2 is in a vacuum state, a pressure difference occurs between the upstream and downstream sides of the upstream valve 31. As a result, the sample gas generated in the impulse heating furnace 1 flows from the outlet suction flow path L1 to the sample gas suction flow path L2 due to this pressure difference and suction by the suction unit 8.

When the sample gas flows through the sample gas suction flow path L2, the element detection unit 5 detects elements contained in the sample gas, and the removal unit 6 removes _CO2 and _H2O from the sample gas.

When the element detection unit 5 finishes detecting the elements contained in the sample gas, the upstream valve 31 is closed by the valve control unit C. The impulse heating furnace 1 is then opened, the crucible R is discarded, and the inside of the impulse heating furnace 1 is cleaned. Note that while the impulse heating furnace 1 is open, the suction unit 8 is sucking the sample gas suction flow path L2 and the exhaust gas suction flow path L3, and the sample gas suction flow path L2 and the exhaust gas suction flow path L3 remain in a vacuum state.

Effects of the First Embodiment
In the analytical device 100 according to the first embodiment, the sample gas flows through the suction flow path L by the suction unit 8 sucking in the sample gas, making it possible to eliminate the need for a carrier gas for flowing the sample gas. Furthermore, since the carrier gas is no longer required, the carrier gas flow path, which is a flow path for flowing the carrier gas, can also be eliminated. As a result, it is possible to reduce the running costs associated with using the carrier gas.

In addition, since the suction unit 8 is provided downstream of the element detection unit 5 in the sample gas suction flow path L2, exhaust gas discharged from the suction unit 8 does not flow into the element detection unit 5. As a result, the element detection unit 5 can accurately detect elements contained in the sample gas.
Moreover, by adjusting the output of the pump which is the suction unit 8, the amount of sample gas sucked into the suction flow path L can be adjusted.

Furthermore, when the sample is heated with the upstream valve 31 closed, sample gas is generated in the impulse heating furnace 1, which creates a pressure difference between the upstream and downstream sides of the upstream valve 31. Therefore, compared to a configuration without valve 3, after the upstream valve 31 is opened, the sample gas can be passed through the element detection unit 5 all at once, improving the detection accuracy, particularly for sample gas generated from low-concentration samples.

In addition, since the valve control unit C opens the upstream valve 31 when the pressure of the sample gas reaches a predetermined level or higher, the time during which the element detection unit 5 detects the elements contained in the sample gas can be adjusted, and the element detection unit 5 can accurately detect the elements contained in the sample gas for both high-concentration samples and low-concentration samples.
Specifically, since a large amount of sample gas is generated from a high-concentration sample, the pressure of the sample gas flowing through the sample gas suction flow path L2 is reduced by setting a low sample gas pressure at which the valve control unit C opens the upstream valve 31. As a result, the signal detected by the element detection unit 5 can be blunted, preventing the signal detected by the element detection unit 5 from being saturated, and the element detection unit 5 can accurately detect elements contained in the sample gas generated from a high-concentration sample.
On the other hand, since a small amount of sample gas is generated from a low-concentration sample, the valve control unit C sets the sample gas pressure at which the upstream valve 31 is opened high, so that when the upstream valve 31 is opened, the sample gas flows into the sample gas suction flow path L2 all at once and the pressure of the sample gas flowing into the sample gas suction flow path L2 increases. As a result, the element detection unit 5 can detect a signal with a clear peak, so that the element detection unit 5 can accurately detect elements contained in the sample gas generated from a low-concentration sample.

Second Embodiment
Next, an analysis device 100 according to a second embodiment of the present invention will be described with reference to Fig. 2. Note that in any of the following figures, some parts may be omitted or exaggerated in schematic form for ease of understanding. The same components are denoted by the same reference numerals and descriptions thereof will be omitted as appropriate.

The components of the second embodiment that differ from the first embodiment are that the crucible R is a ceramic crucible, that the high-frequency heating furnace 1 is used instead of the impulse heating furnace 1, that the element detection unit 5 detects C (carbon) and S (sulfur) contained in the sample gas, and that the removal unit 6 is provided upstream of the sample gas suction flow path L2 from the element detection unit 5 and removes H ₂ O from the sample gas. The other components of the second embodiment are the same as those of the first embodiment. Note that the sample gas suction flow path L2 is suctioned by the suction unit 8 to a vacuum state, and the sample gas may not condense, so the analysis device 100 may not be provided with the removal unit 6.

The analysis method using the analysis device 100 in the second embodiment will be described.

The user places a crucible R inside the high-frequency heating furnace 1. The user also places a sample in a hopper provided at the top of the high-frequency heating furnace 1 and seals the top of the high-frequency heating furnace 1. The specified value receiving unit C1 then receives, through input from the user, the specified value of the pressure of the sample gas when the valve control unit C opens the upstream valve 31.

Next, the opening/closing control unit C3 opens the upstream valve 31, and the downstream valve 32 opens the sample gas suction passage L2 and the exhaust gas suction passage L3. After a predetermined time has elapsed, the suction unit 8 draws the high-frequency heating furnace 1, the outlet suction passage L1, the sample gas suction passage L2, and the exhaust gas suction passage L3 into a vacuum state.

Next, the opening/closing control unit C3 closes the upstream valve 31, sealing the high-frequency heating furnace 1. Then, the user puts the sample from the hopper into the crucible R. After the sample is put into the crucible R, the high-frequency heating furnace 1 heats the sample. In the high-frequency heating furnace 1, sample gas is generated from the sample and the pressure inside the high-frequency heating furnace 1 increases. In the second embodiment, the sample gas contains C (carbon) and S (sulfur). When the high-frequency heating furnace 1 is heating the sample, the suction unit 8 suctions the sample gas suction passage L2 and the exhaust gas suction passage L3 into a vacuum state.

When the pressure measured by the pressure sensor installed upstream of the upstream valve 31 reaches a predetermined value or more, the opening/closing control unit C3 opens the upstream valve 31. The opening/closing control unit C3 also causes the downstream valve 32 to close the exhaust gas suction flow path L3 and open the sample gas suction flow path L2. In the high-frequency heating furnace 1, the pressure rises due to the generation of sample gas, and since the sample gas suction flow path L2 is in a vacuum state, a pressure difference occurs between the upstream and downstream sides of the upstream valve 31. As a result, the sample gas generated in the high-frequency heating furnace 1 flows from the outlet suction flow path L1 to the sample gas suction flow path L2 due to this pressure difference and suction by the suction unit 8.

When the sample gas flows through the sample gas suction flow path L2, the element detection unit 5 detects elements contained in the sample gas, and the removal unit 6 removes H ₂ O from the sample gas.

When the element detection unit 5 finishes detecting the elements contained in the sample gas, the upstream valve 31 is closed by the valve control unit C. After that, the top of the high-frequency heating furnace 1 is opened, the crucible R is discarded, and the inside of the high-frequency heating furnace 1 is cleaned. Note that while the top of the high-frequency heating furnace 1 is open, the suction unit 8 is sucking the sample gas suction flow path L2 and the exhaust gas suction flow path L3, and the sample gas suction flow path L2 and the exhaust gas suction flow path L3 continue to be in a vacuum state.

Effects of the Second Embodiment
According to the analysis device 100 of the second embodiment, in the analysis device 100 for detecting C and S contained in the sample gas generated by heating a sample contained in a ceramic crucible, similarly to the first embodiment, the sample gas flows through the suction flow path L by the suction unit 8 suctioning the sample gas, so that the carrier gas for flowing the sample gas is not required. Furthermore, since the carrier gas is not required, the carrier gas flow path, which is a flow path for flowing the carrier gas, is also not required. As a result, the running costs associated with using the carrier gas can be reduced.

<Other embodiments>
It should be noted that the present invention is not limited to the above-described embodiment.

In the above embodiment, the suction unit 8 suctions the sample gas and exhaust gas, but it is sufficient that the suction unit 8 suctions at least the sample gas. Also, in order for the suction unit 8 to suction at least the sample gas, the suction flow path L may be configured not to include the exhaust gas suction flow path L3.

In the above embodiment, the suction unit 8 is provided downstream of the suction flow path L from the element detection unit 5, but the suction unit 8 may be provided upstream of the suction flow path L from the element detection unit 5.

In the above embodiment, the suction unit 8 is a pump, but this is not limited to this. The suction unit 8 may be, for example, a vacuum chamber. Furthermore, when the above-mentioned analysis device 100 is used in outer space, the downstream side of the suction flow path L may be opened to outer space, making the suction unit 8 unnecessary.

In the above embodiment, the valve control unit C is configured to include a predetermined value receiving unit C1 that receives the predetermined value of the pressure of the sample gas input by the user, but the predetermined value receiving unit C1 may not be included. Specifically, as shown in FIG. 3, the valve control unit C may include a sample type receiving unit C4 that receives the type of sample input by the user, a sample gas amount storage unit C5 that associates and stores the type of sample with the amount of sample gas generated from the sample, and a predetermined value setting unit C6 that, when the sample type receiving unit C4 receives the type of sample, obtains the amount of sample gas associated with the type of sample from the sample gas amount storage unit C5 and sets the predetermined value of the sample gas based on the amount of sample gas obtained from the sample gas amount storage unit C5. With this configuration, even if the user is unable to set the predetermined value of the sample gas depending on his/her ability, the user only needs to input the type of sample, and the predetermined value of the sample gas can be set regardless of the user's ability.

In the above embodiment, the valve control unit C controls the opening and closing of the upstream valve 31 and the downstream valve 32, but it may also control the opening of the upstream valve 31 or the downstream valve 32. With this configuration, the pressure of the sample gas flowing through the sample gas suction flow path L2 can be changed by controlling the opening of the valve 3. In particular, in high-concentration or low-concentration sample gas, changing the pressure of the sample gas can prevent a decrease in detection accuracy caused by the signal detected by the element detection unit 5 becoming extremely large or small.

Specifically, in the case of a high concentration sample gas, the opening of valve 3 is controlled to be small when valve 3 is opened, thereby lowering the pressure of the sample gas flowing through the sample gas suction flow path. As a result, the signal detected by element detection unit 5 can be blunted, preventing the signal detected by element detection unit 5 from becoming saturated, and the element detection unit 5 can accurately detect elements contained in the sample gas generated from a high concentration specimen.

On the other hand, in the case of low-concentration sample gas, the opening of valve 3 is controlled to be large when valve 3 is opened, thereby increasing the pressure of the sample gas flowing through sample gas suction flow path L2. As a result, element detection unit 5 can detect a signal with a clear peak, so element detection unit 5 can accurately detect elements contained in the sample gas generated from a low-concentration specimen.

In the above embodiment, when the suction unit 8 is a pump, the valve control unit C may control the upstream valve 31 and the downstream valve 32 based on the rotation speed of the pump. Specifically, the valve control unit C may further include a rotation speed acquisition unit that acquires the rotation speed of the pump. In this configuration, by controlling, for example, the opening of the valve 3 based on the vacuum state of the sample gas suction flow path L2, the element detection unit 5 can accurately detect elements contained in the sample gas for both high-concentration and low-concentration samples.

Specifically, when the pump rotation speed is low, the sample gas suction flow path L2 is not in a vacuum state compared to when the pump rotation speed is high, so the pressure difference between the upstream and downstream sides of the valve 3 is small. Therefore, by controlling the opening of the valve 3 to a large value when opening the valve 3, particularly in low-concentration samples, the element detection unit 5 can accurately detect the elements contained in the sample gas.

On the other hand, when the pump rotation speed is high, the sample gas suction flow path L2 is in a vacuum state, and the pressure difference between the upstream and downstream sides of the valve 3 is large compared to when the pump rotation speed is low. Therefore, especially in high-concentration samples, by controlling the opening of the valve 3 to a small value when opening the valve 3, the element detection unit 5 can accurately detect the elements contained in the sample gas.

In the above embodiment, the suction unit 8 uses a common pump to suck in the sample gas and exhaust gas, but separate pumps for sucking in the sample gas and exhaust gas may be provided. In this configuration, the sample gas suction flow path L2 is provided with devices such as the oxidizer 4, element detection unit 5, and removal unit 6, and the pressure loss of the sample gas is large, so a pump with a large suction force only needs to be provided in the sample gas suction flow path L2, and a pump with a smaller suction force than the pump provided in the sample gas suction flow path L2 can be provided in the exhaust gas suction flow path L3.

In the above embodiment, the valve 3 is provided upstream of the element detection unit 5 in the suction flow path L, but the valve 3 may be provided downstream of the element detection unit 5 in the suction flow path L.

In the above embodiment, the valve 3 has an upstream valve 31 and a downstream valve 32, but the valve 3 does not have to have two valves, the upstream valve 31 and the downstream valve 32. In order to create a pressure difference between the upstream and downstream sides of the valve 3 and make it easier to suck in the sample gas by the suction unit 8, the valve 3 only needs to have at least the upstream valve 31, and does not have to have the downstream valve 32.

In the above embodiment, the analysis device 100 is configured to include a valve 3 and a valve control unit C, but the analysis device 100 may be configured not to include a valve 3 and a valve control unit C.

In the above embodiment, the element detection unit 5 was an NDIR or TCD, but when detecting elements contained in a sample gas with an NDIR, in order to eliminate the need for a carrier gas that was previously essential for element detection with an NDIR, it is sufficient that at least one of the element detection units 5 is composed of an NDIR, and the other element detection units 5 may be detectors other than NDIR.

In the above embodiment, the impulse heating furnace or high-frequency heating furnace 1 is open to the atmosphere before it is sealed, so for example oxygen or carbon dioxide remains in the impulse heating furnace or high-frequency heating furnace 1. If a sample gas is generated in a state where for example oxygen or carbon dioxide remains in the impulse heating furnace or high-frequency heating furnace 1 and the sample gas flows to the element detection unit 5, for example oxygen or carbon dioxide remaining in the impulse heating furnace or high-frequency heating furnace 1 may also be detected by the element detection unit 5, and accurate measurement may not be possible. Therefore, in order to ensure that no oxygen or carbon dioxide remains in the impulse heating furnace or high-frequency heating furnace 1 when the sample gas is generated, the analysis device 100 may further include an inert gas introduction path P that introduces an inert gas such as nitrogen into the impulse heating furnace or high-frequency heating furnace 1, as shown in FIG. 4.

Specifically, before the impulse heating furnace or high-frequency heating furnace 1 is sealed and the sample is put into the crucible R, the valve control unit C closes the upstream valve 31 and inert gas is introduced into the impulse heating furnace or high-frequency heating furnace 1 through the inert gas introduction path P. Then, when the impulse heating furnace or high-frequency heating furnace 1 is filled with inert gas, the suction unit 8 is started and the valve control unit C opens the upstream valve 31. After a predetermined time has passed, the suction unit 8 sucks in the inert gas, so that the impulse heating furnace or high-frequency heating furnace 1, the outlet suction flow path L1, the sample gas suction flow path L2, and the exhaust gas suction flow path L3 are in a vacuum state. The introduction and suction of the inert gas may be performed multiple times. Moreover, since the introduction of the inert gas is stopped before the sample gas is generated, the inert gas referred to here is not a carrier gas for flowing the sample gas.

Other variations and combinations of the embodiments may be made without going against the spirit of the present invention.

The present invention makes it possible to eliminate the need for a carrier gas to flow the sample gas in an analytical device that detects elements contained in a sample gas generated when the sample is heated and analyzes the elements contained in the sample.

REFERENCE SIGNS LIST 100: Analytical apparatus 1: Impulse heating furnace or high-frequency heating furnace 2: Dust filter 3: Valve 31: Upstream valve 32: Downstream valve 4: Oxidizer 5: Element detection section 6: Removal section 7: Flow rate measurement section 8: Suction section L: Suction flow path L1: Output suction flow path L2: Sample gas suction flow path L3: Exhaust gas suction flow path R: Crucible

Claims (11)

an impulse heating furnace or a high-frequency heating furnace for heating a sample to generate a sample gas containing elements constituting the sample;
a suction flow path for suctioning the sample gas generated in the impulse heating furnace or the high-frequency heating furnace by a suction part;
an element detection unit provided in the suction flow path for detecting the element contained in the sample gas. A valve provided in the suction flow path;
A valve control unit for controlling the valve is further provided.
the suction unit is provided downstream of the suction flow path relative to the valve,
the valve control unit closes the valve when the impulse heating furnace or the high-frequency heating furnace is heating the sample, and opens the valve when the pressure of the sample gas becomes equal to or higher than a predetermined pressure;
The analytical device according to claim 1 , wherein the suction unit suctions the sample gas when the valve is opened. The analytical device according to claim 2, wherein the valve control unit opens the valve when the pressure of the sample gas inside the impulse heating furnace or the high-frequency heating furnace is equal to or greater than a predetermined value, or when the difference between the pressure on the upstream side and the pressure on the downstream side of the valve is equal to or greater than a predetermined value. The analytical device according to claim 2 or 3, wherein the valve control unit further includes a predetermined value receiving unit that receives a predetermined value of the pressure of the sample gas input by a user. The valve control unit is
a sample type receiving unit that receives the sample type input by a user;
a sample gas amount storage unit that stores the type of the sample and the amount of the sample gas generated from the sample in association with each other;
The analytical apparatus of claim 2 or 3, further comprising a predetermined value setting unit that, when the sample type receiving unit receives the type of sample, obtains from the storage unit an amount of the sample gas associated with the type of sample, and sets a predetermined value of the sample gas based on the amount of the sample gas obtained from the storage unit. The analytical device according to any one of claims 2 to 5, wherein the valve control unit controls the opening of the valve based on the pressure of the sample gas. The suction unit is a pump,
The analysis device further includes a rotation speed acquisition unit that acquires a rotation speed of the pump,
The analyzer according to claim 2 , wherein the valve control unit controls the valve based on the rotation speed of the pump acquired by the rotation speed acquisition unit. The analytical device according to any one of claims 2 to 7, wherein the valve is provided upstream of the suction flow path from the element detection unit. The analytical device according to any one of claims 1 to 8, wherein the suction unit is a pump provided downstream of the suction flow path from the element detection unit. The analysis device according to any one of claims 1 to 9, wherein at least one of the element detection units is a non-dispersive infrared gas analyzer. A sample is heated to generate a sample gas containing elements constituting the sample in an impulse heating furnace or a high-frequency heating furnace;
The sample gas generated in the impulse heating furnace or the high-frequency heating furnace is sucked in by a suction part,
The analysis method further comprises: providing a device in the suction flow path to detect the element contained in the sample gas.

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