Analysis device and analysis method

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

[0001] The present invention relates to an analytical device and an analytical method.

[0002] Conventional analytical devices include, for example, those disclosed in Patent Document 1, which analyze 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.

[0003] Japanese Patent Application Laid-Open No. 2022-65206

[0004] Here, in the above-mentioned analyzer, it is necessary to continuously flow carrier gas to flow the sample gas to the detector, and therefore it is necessary to use a large amount of carrier gas, which results in high running costs.

[0005] Therefore, the present invention has been made in consideration of the above-mentioned problems, and its main objective is to eliminate the need for a carrier gas for flowing sample gas in an analytical device that detects elements contained in sample gas generated when a sample is heated and analyzes the elements contained in the sample.

[0006] That is, the analytical device according to the present invention is characterized by comprising an impulse heating furnace or a high-frequency heating furnace that heats a sample and generates a sample gas containing elements that constitute the sample, an suction flow path that draws in the sample gas generated in the impulse heating furnace or the high-frequency heating furnace using an suction unit, and an element detection unit that is provided in the suction flow path and detects the elements contained in the sample gas.

[0007] In such an analyzer, the sample gas flows through the suction flow path when the suction unit draws in the sample gas, eliminating the need for carrier gas to drive the sample gas, and as a result, reducing the running costs associated with using carrier gas.

[0008] It is preferable that the analytical device further includes 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 a predetermined level or higher, and the suction unit suctioning the sample gas when the valve is opened.

[0009] With this configuration, when the sample is heated with the valve closed, the sample gas generated in the impulse heating furnace or high-frequency heating furnace creates a pressure difference between the upstream and downstream sides of the valve. Therefore, compared to a configuration without a valve, after the valve is opened, the sample gas can be passed through the element detection unit all at once, thereby improving detection accuracy, particularly for sample gas generated from low-concentration samples. Furthermore, because the valve control unit opens the valve when the sample gas pressure reaches a predetermined level or higher, the time during which the element detection unit detects elements contained in the sample gas can be adjusted, and the element detection unit can accurately detect elements contained in the sample gas for both high-concentration and low-concentration samples.

[0010] A specific embodiment of the valve control unit is one 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 in pressure between the upstream side and the downstream side of the valve is equal to or greater than a predetermined value.

[0011] A specific embodiment of the valve control section may further include a predetermined value receiving section that receives a predetermined value of the pressure of the sample gas set by a user.

[0012] The valve control unit may further include a sample type receiving unit that receives the type of sample input by a user, a sample gas amount storage unit that stores the type of sample in association with the amount of sample gas generated from the sample, and a predetermined value setting unit that, when the sample type receiving 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.

[0013] With this configuration, even if a user is unable to set a specified value for the sample gas due to their skill level, the user only needs to input the type of sample, and the specified value for the sample gas can be set regardless of the user's skill level.

[0014] The valve control unit may be configured to control the opening of the valve based on the pressure of the sample gas.

[0015] With this configuration, the pressure of the sample gas flowing through the suction channel can be changed by controlling the valve opening, which prevents a decrease in detection accuracy due to the signal detected by the element detection unit becoming extremely large or small, particularly in the case of high-concentration or low-concentration sample gas, by changing the sample gas pressure.

[0016] The suction unit is a pump, the analytical 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.

[0017] With this configuration, by controlling, for example, the opening degree of the valve 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 samples and low-concentration samples.

[0018] The valve is preferably provided upstream of the element detection unit in the suction flow path.

[0019] With this configuration, the sample gas generated in the impulse heating furnace or high-frequency heating furnace flows to the element detection section when the valve is opened, making it easier for the element detection section to detect the elements contained in the sample gas compared to a configuration in which the sample gas generated in the heating furnace flows directly to the element detection section.

[0020] A specific example of the suction unit is a pump provided downstream of the element detection unit in the suction flow path.

[0021] With this configuration, the suction unit is located downstream of the element detection unit in the suction flow path, so exhaust gas discharged from the suction unit does not flow into the element detection unit. As a result, the element detection unit can accurately detect elements contained in the sample gas. Furthermore, by adjusting the pump output, the amount of sample gas drawn into the suction flow path can be adjusted.

[0022] Conventional non-dispersive infrared gas analyzers (hereinafter referred to as NDIR) require a continuous flow of carrier gas to allow the sample gas to flow, but it is preferable that at least one of the element detection units of the present invention is a non-dispersive infrared gas analyzer.

[0023] With this configuration, when detecting elements contained in a sample gas by NDIR, it is possible to eliminate the need for a carrier gas, which has conventionally been essential for element detection by NDIR.

[0024] The analytical method is 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.

[0025] With this configuration, it is possible to obtain the same effects as those of the above-described analyzer.

[0026] According to the present invention configured in this manner, a carrier gas can be eliminated 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.

[0027] It is a schematic diagram showing an analytical device according to a first embodiment of the present invention. It is a schematic diagram showing an analytical device according to a second embodiment of the present invention. It is a schematic diagram showing a functional block of a valve control unit in another embodiment of the present invention. It is a schematic diagram showing an analytical device in another embodiment of the present invention.

[0028] First Embodiment An analysis device 100 according to a first embodiment of the present invention will be described below with reference to the drawings. Note that in all of the drawings shown below, some parts may be omitted or exaggerated as appropriate for ease of understanding. Identical components will be assigned the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0029] 1, the analytical device 100 according to this embodiment analyzes elements contained in a sample by heating the sample contained in a crucible R and detecting elements contained in a sample gas containing elements constituting the sample. In this embodiment, the crucible R is a graphite crucible.

[0030] 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.

[0031] The impulse heating furnace 1 is configured to hold a crucible R containing a sample and heat the sample in the crucible R to generate a sample gas. In this embodiment, the impulse heating furnace 1 heats the crucible R before the sample is placed in the crucible R, thereby generating exhaust gas from the crucible R. In this embodiment, a hopper (not shown) for introducing the sample into the crucible R is provided above the impulse heating furnace 1.

[0032] 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.

[0033] The dust filter 2 filters out soot and other particles contained in the gas discharged from the impulse heating furnace 1 to remove dust.

[0034] The valve 3 opens and closes the suction flow path L. Specifically, the valve 3 has an upstream valve 31 provided upstream of the dust filter 2 in the outlet suction flow path L1, and a downstream valve 32 provided downstream of the dust filter 2 in the outlet suction flow path L1. In this embodiment, the upstream valve 31 opens and closes the outlet suction flow path L1. The downstream valve 32 is a so-called three-way valve, and opens and closes the sample gas suction flow path L2 and the exhaust gas suction flow path L3.

[0035] In this embodiment, the valve 3 is controlled by a 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 predetermined area of ​​the memory.

[0036] 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 obtaining unit C2 that obtains 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 being measured by a pressure sensor provided upstream of the upstream valve 31, and may also be measured by a differential pressure gauge that measures the pressure difference upstream and downstream of the upstream valve 31.

[0037] The sample gas intake flow path L2 is provided with an oxidizer 4 that oxidizes the sample gas, an element detector 5 that detects elements contained in the sample gas, a remover 6 that removes components contained in the sample gas, and a flow rate measuring unit 7 that measures the flow rate of the sample gas. The configuration of each unit provided in the sample gas intake flow path L2 will be described below.

[0038] The oxidizer 4 is provided downstream of a CO detector 51 (to be described later) in the sample gas intake flow path L2, and converts CO contained in the sample gas into CO ２ 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 or the like.

[0039] The element detection unit 5 includes a CO detection unit 51, a CO ２ Detection unit 52, H ２ O detector 53 and N ２ The CO detector 51 is configured with a CO detector 54. ２ Detection unit 52, H ２ O detector 53 and N ２ The detectors 54 are provided in this order from the upstream side of the sample gas suction flow path L2.

[0040] The CO detector 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 detector 51 is an NDIR (non-dispersive infrared gas analyzer). Due to its measurement accuracy, the CO detector 51 operates effectively when the oxygen concentration inside the sample is high. Specifically, the CO detector 51 preferably measures CO of 150 ppm or more.

[0041] CO ２ The detection unit 52 detects CO in the sample gas that has passed through the oxidation unit 4. ２ In this embodiment, CO ２ The detector 52 is an NDIR. ２ From the viewpoint of measurement accuracy, the detection unit 52 operates effectively when the oxygen concentration contained in the sample is low (for example, less than 150 ppm).

[0042] H ２ The O detector 53 detects CO ２ H in the sample gas that has passed through the detection unit 52 ２ In this embodiment, H ２ The O detection unit 53 is an NDIR. ２ The temperature of the sample gas in the sample gas intake flow path L2 up to the O detection unit 53 is kept at 100°C or higher. ２ O is kept in the state of water vapor. In this way, measurement errors caused by condensation are eliminated. ２ The O detector 53 is designed to prevent this from occurring.

[0043] N ２ The detection unit 54 detects H ２ The N in the sample gas that has passed through the O detection unit 53 and the removal unit 6 described later ２ In this embodiment, N ２ The detector 54 is a thermal conductivity detector (TCD).

[0044] The removal unit 6 removes CO from the sample gas. ２ and H ２ In this embodiment, the removal unit 6 adsorbs and removes CO in the sample gas. ２ Removes CO ２ The removal unit 61 and the H in the sample gas ２ H to remove O ２ The CO removal unit 62 ２ Removal section 61 and H ２ The O removal section 62 is made of an adsorbent, and the material of the adsorbent is, for example, a zeolite molecular sieve, silica gel, activated carbon, or ascharite.

[0045] The flow rate measuring unit 7 is N ２ The detection unit 54 is a flow rate sensor that measures the flow rate of the sample gas that has passed through it.

[0046] The suction unit 8 sucks in the sample gas generated in the impulse heating furnace 1 and causes the sample gas to flow 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 causes the exhaust gas to flow into the exhaust gas suction flow path L3.

[0047] 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. In this embodiment, the suction unit 8 is a pump. Specifically, the suction unit 8, which is a pump, suctions the sample gas or exhaust gas and exhausts the suctioned sample gas or exhaust gas to the outside of the analytical device 100.

[0048] <Analysis Method> An analysis method using the analysis device 100 of this embodiment will be described below.

[0049] 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 predetermined value receiving unit C1 then receives, through input from the user, a predetermined value for the pressure of the sample gas when the valve control unit C opens the upstream valve 31.

[0050] Next, the opening / closing control unit C3 opens the upstream valve 31. 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. Then, the suction unit 8 is activated 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, the outlet suction passage L1, the sample gas suction passage L2, and the exhaust gas suction passage L3.

[0051] Next, the open / close 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 applies suction, creating a vacuum in the sample gas suction flow path L2 and the exhaust gas suction flow path L3.

[0052] When the pressure measured by a pressure sensor provided upstream of the upstream valve 31 reaches a predetermined value or higher, 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.

[0053] When the sample gas flows through the sample gas intake flow path L2, the element detection unit 5 detects elements contained in the sample gas, and the removal unit 6 detects CO ２ and H ２ Remove O.

[0054] 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. Thereafter, the impulse heating furnace 1 is opened, the crucible R is discarded, and the interior 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 passage L2 and the exhaust gas suction passage L3, and the sample gas suction passage L2 and the exhaust gas suction passage L3 continue to be in a vacuum state.

[0055] Effect of First Embodiment In the analyzer 100 according to the first embodiment, the sample gas flows through the suction flow path L when the suction unit 8 suctions the sample gas, eliminating the need for a carrier gas to flow the sample gas. Furthermore, because no carrier gas is required, the carrier gas flow path, which is a flow path for flowing the carrier gas, is also unnecessary. As a result, the running costs associated with using a carrier gas can be reduced.

[0056] Furthermore, since the suction unit 8 is located downstream of the element detection unit 5 in the sample gas suction flow path L2, the 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 the elements contained in the sample gas. Furthermore, by adjusting the output of the pump that is the suction unit 8, the amount of sample gas suctioned into the suction flow path L can be adjusted.

[0057] Furthermore, when the sample is heated with the upstream valve 31 closed, sample gas is generated in the impulse heating furnace 1, causing 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, thereby improving the detection accuracy, particularly for sample gas generated from low-concentration samples.

[0058] Furthermore, because 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 elements contained in the sample gas can be adjusted, allowing the element detection unit 5 to accurately detect elements contained in the sample gas for both high-concentration and low-concentration samples. Specifically, since a large amount of sample gas is generated in a high-concentration sample, the valve control unit C sets a low sample gas pressure at which the upstream valve 31 is opened, thereby lowering the pressure of the sample gas flowing through the sample gas intake flow path L2. As a result, the signal detected by the element detection unit 5 can be blunted, preventing saturation of the signal detected by the element detection unit 5 and allowing the element detection unit 5 to accurately detect elements contained in the sample gas generated from a high-concentration sample. On the other hand, since a low-concentration sample generates a small amount of sample gas, the valve control unit C sets a high sample gas pressure at which the upstream valve 31 is opened, so that when the upstream valve 31 is opened, the sample gas flows all at once into the sample gas intake flow path L2, and the pressure of the sample gas flowing through the sample gas intake flow path L2 increases. As a result, the element detection unit 5 can detect a signal with a clear peak, and therefore the element detection unit 5 can accurately detect elements contained in the sample gas generated from a low-concentration sample.

[0059] 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 all of the following figures, some parts may be omitted or exaggerated as appropriate for ease of understanding. Identical components are denoted by the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0060] 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 element detection unit 5 in the sample gas suction flow path L2 and detects H in the sample gas. ２The 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 create a vacuum state, and the sample gas may not condense, so the analyzer 100 may be configured without the removal unit 6.

[0061] An analysis method using the analysis device 100 in the second embodiment will be described.

[0062] 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 predetermined value receiving unit C1 then receives, through input from the user, a predetermined value for the pressure of the sample gas when the valve control unit C opens the upstream valve 31.

[0063] Next, the opening / closing control unit C3 opens the upstream valve 31, and opens the sample gas suction channel L2 and the exhaust gas suction channel L3 by the downstream valve 32. After a predetermined time has passed, the suction unit 8 suctions the high-frequency heating furnace 1, the outlet suction channel L1, the sample gas suction channel L2, and the exhaust gas suction channel L3, creating a vacuum state.

[0064] Next, the opening / closing control unit C3 closes the upstream valve 31, sealing the high-frequency heating furnace 1. Then, the user loads the sample from the hopper into the crucible R. After the sample is loaded 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). While the high-frequency heating furnace 1 is heating the sample, the suction unit 8 suctions, creating a vacuum in the sample gas suction flow path L2 and the exhaust gas suction flow path L3.

[0065] When the pressure measured by a pressure sensor provided upstream of the upstream valve 31 reaches a predetermined value or higher, 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 increases due to the generation of sample gas, and the sample gas suction flow path L2 is in a vacuum state, so 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.

[0066] When the sample gas flows through the sample gas intake flow path L2, the element detection unit 5 detects elements contained in the sample gas, and the removal unit 6 removes H in the sample gas. ２ Remove O.

[0067] 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. Thereafter, 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 passage L2 and the exhaust gas suction passage L3, and the sample gas suction passage L2 and the exhaust gas suction passage L3 continue to be in a vacuum state.

[0068] Effect of Second Embodiment According to the analytical device 100 of the second embodiment, even in the analytical device 100 that detects C and S contained in sample gas generated by heating a sample contained in a ceramic crucible, as in the first embodiment, the sample gas flows through the suction flow path L when the suction unit 8 suctions the sample gas, thereby eliminating the need for a carrier gas for flowing the sample gas. Furthermore, since no carrier gas is required, the carrier gas flow path, which is a flow path for flowing the carrier gas, is also unnecessary. As a result, the running costs associated with using a carrier gas can be reduced.

[0069] Other Embodiments The present invention is not limited to the above-described embodiment.

[0070] In the above embodiment, the suction unit 8 suctions the sample gas and the exhaust gas, but it is sufficient that the suction unit 8 suctions at least the sample gas. In addition, in order for the suction unit 8 to suction at least the sample gas, the suction flow path L may not be provided with the exhaust gas suction flow path L3.

[0071] In the above embodiment, the suction section 8 was provided downstream of the suction flow path L from the element detection section 5, but the suction section 8 may also be provided upstream of the suction flow path L from the element detection section 5.

[0072] In the above embodiment, the suction unit 8 is a pump, but this is not limiting. The suction unit 8 may be, for example, a vacuum chamber. Furthermore, when the above-described analysis device 100 is used in outer space, the downstream side of the suction flow path L may be open to outer space, making the suction unit 8 unnecessary.

[0073] In the above embodiment, the valve control unit C includes a predetermined value receiving unit C1 that receives the predetermined value of the sample gas pressure input by the user. However, 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 sample type input by the user, a sample gas amount storage unit C5 that stores the sample type and the amount of sample gas generated from the sample in association with each other, and a predetermined value setting unit C6 that, when the sample type receiving unit C4 receives the sample type, retrieves the amount of sample gas associated with the sample type from the sample gas amount storage unit C5 and sets the predetermined value of the sample gas based on the amount of sample gas retrieved from the sample gas amount storage unit C5. With this configuration, even if a user is unable to set the predetermined value of the sample gas due to their skill level, the user only needs to input the sample type, and the predetermined value of the sample gas can be set regardless of the user's skill level.

[0074] 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 aperture of either the upstream valve 31 or the downstream valve 32. With this configuration, the pressure of the sample gas flowing through the sample gas intake flow path L2 can be changed by controlling the aperture of the valve 3. In particular, for high-concentration or low-concentration sample gas, changing the sample gas pressure can prevent a decrease in detection accuracy due to the signal detected by the element detection unit 5 becoming extremely large or small.

[0075] Specifically, in the case of a highly concentrated sample gas, the opening of the valve 3 is controlled to be small when the valve 3 is opened, thereby lowering the pressure of the sample gas flowing through the sample gas intake passage. 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 becoming saturated, and enabling the element detection unit 5 to accurately detect elements contained in the sample gas generated from a highly concentrated specimen.

[0076] On the other hand, in the case of low-concentration sample gas, the pressure of the sample gas flowing through the sample gas intake flow path L2 increases by controlling the valve 3 to a large opening when the valve 3 is opened. As a result, the element detection unit 5 can detect a signal with a clear peak, and therefore the element detection unit 5 can accurately detect elements contained in the sample gas generated from a low-concentration specimen.

[0077] 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. With 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 samples and low-concentration samples.

[0078] 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, and therefore the pressure difference between the upstream and downstream sides of the valve 3 is small. Therefore, particularly for low-concentration samples, by controlling the valve 3 to a large opening when opening it, the element detection unit 5 can accurately detect elements contained in the sample gas.

[0079] On the other hand, when the pump rotation speed is high, the sample gas suction flow path L2 is in a vacuum state compared to when the pump rotation speed is low, and the pressure difference between the upstream and downstream sides of the valve 3 is therefore greater. Therefore, particularly in the case of a highly concentrated sample, by controlling the opening of the valve 3 to a small value when opening it, the element detection unit 5 can accurately detect elements contained in the sample gas.

[0080] In the above embodiment, the suction unit 8 uses a common pump to suck in the sample gas and the exhaust gas, but separate pumps for sucking in the sample gas and the exhaust gas may be provided. In this configuration, the sample gas suction flow path L2 is provided with devices such as the oxidizer 4, the element detection unit 5, and the removal unit 6, and the pressure loss of the sample gas is large. Therefore, a pump with a large suction force need only 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.

[0081] 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 also be provided downstream of the element detection unit 5 in the suction flow path L.

[0082] In the above embodiment, the valve 3 has the upstream valve 31 and the 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 generate 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.

[0083] In the above embodiment, the analytical device 100 is configured to include the valve 3 and the valve control unit C. However, the analytical device 100 may be configured not to include the valve 3 and the valve control unit C.

[0084] In the above embodiment, the element detection unit 5 was an NDIR or a TCD, but when detecting elements contained in a sample gas using an NDIR, in order to eliminate the need for a carrier gas, which was previously essential for element detection using 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.

[0085] In the above embodiment, the impulse heating furnace or high-frequency heating furnace 1 is open to the atmosphere before being sealed, and therefore, for example, oxygen or carbon dioxide remains in the impulse heating furnace or high-frequency heating furnace 1. If sample gas is generated in a state in which, for example, oxygen or carbon dioxide remains in the impulse heating furnace or high-frequency heating furnace 1 and the sample gas flows into the element detection unit 5, the 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, which may result in an inaccurate measurement. Therefore, in order to ensure that, for example, oxygen or carbon dioxide does not remain 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 inlet path P for introducing, for example, nitrogen into the impulse heating furnace or high-frequency heating furnace 1, as shown in FIG.

[0086] Specifically, before the impulse heating furnace or high-frequency heating furnace 1 is sealed and the sample is placed in 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 inlet path P. Then, once the impulse heating furnace or high-frequency heating furnace 1 is filled with inert gas, the suction unit 8 is activated, and the valve control unit C opens the upstream valve 31. After a predetermined time has elapsed, the suction unit 8 draws in the inert gas, thereby creating a vacuum in the impulse heating furnace or high-frequency heating furnace 1, the outlet suction path L1, the sample gas suction path L2, and the exhaust gas suction path L3. The introduction and suction of the inert gas may be performed multiple times. Furthermore, because the introduction of the inert gas is stopped before sample gas is generated, the inert gas referred to here is not a carrier gas for flowing the sample gas.

[0087] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention.

[0088] According to the present invention, 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, it is possible to eliminate the need for a carrier gas for flowing the sample gas.

[0089] 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: Outlet suction flow path L2: Sample gas suction flow path L3: Exhaust gas suction flow path R: Crucible

Claims

1. An analytical device comprising: an impulse heating furnace or a high-frequency heating furnace that heats a sample and generates a sample gas containing elements that constitute the sample; an aspiration flow path that draws in the sample gas generated in the impulse heating furnace or the high-frequency heating furnace using an aspiration unit; and an element detection unit provided in the aspiration flow path that detects the elements contained in the sample gas.

2. The analytical device of claim 1, further comprising a valve provided in the suction flow path and a valve control unit that controls the valve, wherein the suction unit is provided downstream of the suction flow path from 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 reaches or exceeds a predetermined value, and the suction unit draws in the sample gas when the valve is opened.

3. The analytical device described in 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 in pressure between the upstream and downstream sides of the valve is equal to or greater than a predetermined value.

4. The analytical device according to claim 2 or 3, wherein the valve control section further comprises a predetermined value receiving section that receives a predetermined value of the pressure of the sample gas input by a user.

5. The analytical apparatus of claim 2 or 3, wherein the valve control unit further comprises: a sample type receiving unit that receives the type of sample input by a user; a sample gas amount storage unit that stores the type of sample in association with the amount of sample gas generated from the sample; and a predetermined value setting unit that, when the sample type receiving unit receives the type of sample, obtains the amount of sample gas linked to 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.

6. The analytical device according to any one of claims 2 to 5, wherein the valve control section controls the opening degree of the valve based on the pressure of the sample gas.

7. The analytical device according to any one of claims 2 to 6, wherein the suction unit is a pump, the analytical device further comprises 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.

8. 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.

9. 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.

10. The analytical 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.

11. An analytical method comprising: heating a sample to generate a sample gas containing elements constituting the sample in an impulse heating furnace or a high-frequency heating furnace; sucking in the sample gas generated in the impulse heating furnace or the high-frequency heating furnace using an suction section provided in the suction flow path; and detecting the elements contained in the sample gas.

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