Elemental analysis method and elemental analysis device

Abstract

To enable analysis time to be reduced in an element analysis device.SOLUTION: Provided is an element analysis method for analyzing a sample using an element analysis device comprising a furnace body of a tubular shape with a sample inlet provided at one end, which causes a temperature gradient to occur along its tube axis direction and an analyzer that analyzes an analysis object gas generated from the sample heated in the furnace body. This analysis method is characterized in that the sample in the furnace body is moved along the tube axis direction while analysis of the sample is underway and the temperature of the sample is thereby changed.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an elemental analysis method and an elemental analysis device for analyzing elements such as carbon (C) and sulfur (S) contained in samples such as steel, non-ferrous metals, and ceramics. [Background technology]

[0002] A conventional elemental analyzer includes a vessel (boat) containing a sample, which is placed in a tubular heating furnace, and the sample is heated and combusted in the heating furnace, and the target gas generated from the sample is analyzed, as shown in Patent Document 1. The heating furnace of this elemental analyzer has an opening formed in the side wall for inserting and removing the sample, and a space for placing the vessel extends horizontally from the opening.

[0003] In such elemental analyzers, in addition to total analysis in which the entire amount of the analysis target gas generated from the heated sample is introduced to an analyzer for analysis, so-called temperature-rise analysis can be performed in which the temperature of the sample is raised stepwise over time, and the generated analysis target gas is separated by temperature and introduced to an analyzer for analysis. Conventionally, when such a temperature-rise analysis is performed, the operator changes the temperature setting of the heating furnace during the analysis, but it takes time for the temperature in the heating furnace to actually rise to the set temperature, which results in a long total analysis time. In addition, when performing temperature-rise analysis on multiple samples in sequence, even if the temperature setting of the heating furnace is changed to lower the temperature in the furnace between the analyses of each sample, it takes time for the temperature in the furnace to actually drop to the target temperature, which results in a long total analysis time. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-273288 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above problems, and it is an object of the present invention to provide an elemental analysis method and an elemental analysis apparatus that can shorten the analysis time compared to the conventional methods. [Means for solving the problem]

[0006] As a result of intensive research to solve the above problems, the inventors have noticed that the temperature distribution in a tubular heating furnace is non-uniform and that a temperature gradient occurs along the tube axis direction. They have discovered that by utilizing this temperature gradient, the temperature of a sample can be changed in a short time during analysis without changing the temperature setting of the heating furnace, and have arrived at the present invention.

[0007] In other words, the elemental analysis method of the present invention is a method for analyzing a sample using an elemental analysis apparatus that is tubular with a sample inlet at one end and includes a furnace body that generates a temperature gradient along the tube axis direction, and an analyzer that analyzes the target gas generated from the sample heated in the furnace body, and is characterized in that the temperature of the sample is changed by moving the sample in the furnace body along the tube axis direction during analysis of the sample.

[0008] In such an elemental analysis method, the temperature of the sample is changed during analysis by moving the sample in the furnace body having a temperature gradient, so that the sample temperature can be changed in a short time without changing the set temperature of the furnace body, for example, during a temperature rise analysis, etc. This makes it possible to shorten the analysis time compared to conventional analysis methods in which the sample temperature is changed by changing the set temperature of the furnace body.

[0009] A specific embodiment of the elemental analysis method includes a heating analysis in which the temperature of the sample is raised stepwise by moving the sample stepwise from a relatively low temperature region to a relatively high temperature region within the furnace body during analysis of the sample. In such an elemental analysis method, the temperature gradient within the furnace body is utilized to raise the temperature of the sample, so that the temperature-raising analysis of the sample can be completed in a short time.

[0010] In one embodiment in which the elemental analysis method of the present invention exhibits a remarkable effect, a plurality of the samples are sequentially placed in the furnace body and the heating analysis is carried out successively. When performing temperature rise analysis on multiple samples in succession, in the conventional method of changing the temperature of the furnace body to change the temperature of the samples, it is necessary to cool the furnace body every time a temperature rise analysis is completed and a sample is replaced. However, in the elemental analysis method of the present invention, the temperature distribution in the furnace body (i.e., high and low temperature areas) is used to perform the temperature rise analysis, so there is no need to change the temperature of the furnace body between each temperature rise analysis. This makes it possible to significantly shorten the total analysis time.

[0011] The elemental analysis method is also characterized in that a temperature distribution indicating the relationship between temperature and position along the tube axis in the furnace body is acquired before analysis begins, and the temperature of the sample is set to a predetermined target temperature by moving the sample with reference to the acquired temperature distribution. In this way, by understanding the relationship between the position in the furnace body and the temperature, the temperature of the sample can be set to an accurate target value in a short period of time.

[0012] In the elemental analysis method, it is preferable that the temperature of the sample is changed by moving the sample in the furnace body along the tube axis with the sample inlet closed. In this way, since there is no need to open and close the sample insertion port, the temperature of the sample can be changed in a shorter time, and the analysis time can be further shortened.

[0013] In addition, the elemental analysis apparatus of the present invention, which realizes the elemental analysis method of the present invention, is tubular with a sample inlet at one end and is characterized in that it comprises a furnace body that generates a temperature gradient along the tube axis direction, an analyzer that analyzes the target gas generated from the sample heated in the furnace body, and a sample position adjustment mechanism that can move the sample in the furnace body along the tube axis direction with the sample inlet closed.

[0014] Such a device is equipped with a sample position adjustment mechanism that moves the sample within the furnace body, which has a temperature gradient, so that, for example, during heating analysis, the temperature of the sample can be changed in a short time by moving the sample within the furnace body along the axial direction of the tube without changing the set temperature of the furnace body.

[0015] It is preferable that the sample position adjustment mechanism is provided at a position opposite the sample insertion port in the furnace body and is configured to be able to push the sample in the furnace body toward the sample insertion port along the tube axis. In this way, after setting the sample in the inner part of the furnace body, which is a low-temperature region, the temperature of the sample can be increased stepwise by pushing the sample toward the sample inlet using the sample position adjustment mechanism. After the sample analysis is completed, the sample inlet can be opened and the sample can be pushed and moved by the sample position adjustment mechanism, allowing the sample to be automatically removed from the sample inlet.

[0016] A specific configuration of the elemental analysis apparatus includes one further comprising a blocking member for blocking the opening on the other end side of the furnace body, and the sample position adjustment mechanism including a sample manipulation rod that penetrates the blocking member along the tube axial direction and has an operating surface at its tip for pushing out the sample, and a drive unit that moves the sample manipulation rod back and forth along the tube axial direction.

[0017] As a specific configuration of the sample position adjustment mechanism, the sample manipulation rod is provided so that its tip is always positioned within the furnace body during analysis.

[0018] It is also preferable that the sample position adjustment mechanism is equipped with a cooling mechanism for cooling the sample manipulating rod, and that the cooling mechanism is equipped with an internal flow path formed in the sample manipulating rod and a cold water supply mechanism for supplying cold water to the internal flow path. In this manner, the temperature of the sample manipulating rod can be kept low even when the furnace body is heated, thereby preventing the sealing member between the sample manipulating rod and the blocking member from burning and allowing the sample manipulating rod to remain positioned within the furnace body.

[0019] A specific configuration of the elemental analyzer is such that a gas outlet port for leading the gas to be analyzed generated in the furnace body to the analyzer is formed in the closing member.

[0020] In the elemental analyzer, it is preferable that the sample position adjustment mechanism is configured to be able to move the sample in the furnace body along the tube axial direction with the sample insertion port closed. In this way, since there is no need to open and close the sample insertion port, the temperature of the sample can be changed in a shorter time, and the analysis time can be further shortened. Effect of the Invention

[0021] According to the present invention thus configured, it is possible to provide an elemental analysis method and an elemental analysis device that can shorten the analysis time. [Brief description of the drawings]

[0022] [Figure 1] 1 is a diagram illustrating a schematic configuration of an elemental analysis apparatus according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a diagram showing an example of a temperature distribution in a heating furnace according to the embodiment. [Diagram 3] FIG. 2 is a functional block diagram of the elemental analyzer of the embodiment. [Figure 4] 6 is a diagram showing an example of the relationship between the time change in signal intensity of a gas analyzer and the operation timing of a sample position adjustment mechanism in a temperature-programmed analysis using the elemental analyzer of the embodiment. FIG. [Diagram 5] FIG. 4 is a diagram for explaining an example of the operation of the elemental analyzer of the embodiment. [Figure 6] FIG. 13 is a diagram illustrating a schematic configuration of an elemental analyzer according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0023] An elemental analyzer 100 according to an embodiment of the present invention will be described below with reference to the drawings.

[0024] The elemental analysis apparatus 100 of this embodiment heats and combusts a sample S such as a metal, and analyzes elements contained in the sample S, such as carbon (C) and sulfur (S), from the gas generated by the combustion.

[0025] Specifically, as shown in FIG. 1, this elemental analysis apparatus 100 includes a heating furnace 1 in which a container V containing a sample S is placed, and a gas analyzer 2 that analyzes gas (also referred to as the analysis target gas) produced from the sample S heated and combusted in the heating furnace 1.

[0026] The container V contains, for example, a powdered sample S. The container V in this embodiment is an elongated container having an opening at the top, and is specifically a ceramic combustion boat, a ceramic board, a quartz board, or the like. Note that the shape of the container V is not limited to this, and various shapes are possible.

[0027] The heating furnace 1 is a tubular furnace having a heating space 1S extending horizontally therein, in which a container V not containing a sample S is baked empty or a container V containing a sample S is heated to heat the sample S and generate a gas to be analyzed. Specifically, the heating furnace 1 includes a furnace body 11 that forms the heating space 1S, and an electric resistor 12 that is provided around the furnace body 11 and heats the furnace body 11.

[0028] The furnace body 11 is a tubular (straight) ceramic molded body, and both ends along the tube axis are open. An opening 11a at one end of the furnace body 11 functions as a sample input port 1P for inputting a container V into the heating space 1S. An opening 11b at the other end communicates with a gas outlet 1Q for introducing the target gas generated from the sample S to the analyzer 2.

[0029] As shown in FIG. 1, the heating furnace 1 further includes an opening / closing mechanism 13 for opening and closing the sample inlet 1P of the furnace body 11. The opening / closing mechanism 13 includes a block-shaped cover member 131 capable of closing the sample inlet 1P, and a drive unit 132 for moving the cover member 131. The drive unit 132 includes an actuator such as an air cylinder (not shown), and slides the cover member 131 between an open position for opening the sample inlet 1P and a closed position for closing the sample inlet 1P. At the closed position, a closing surface 131s of the cover member 131 closes the sample inlet 1P via a sealing member such as an O-ring. At the closed position, the closing surface 131s forms a part of the side wall of the heating space 1S.

[0030] The heating furnace 1 also includes a blocking member 14 that seals and closes the opening 11b on the other end side of the furnace body 11. The blocking member 14 is cylindrical with one end open along the axial direction, and is configured to fit and hold the outer peripheral side surface of the furnace body 11 via a sealing member such as an O-ring. The blocking member 14 has a blocking surface 14s that blocks the opening 11b on the other end side of the furnace body 11, and this blocking surface 14s forms a part of the side wall of the heating space 1S.

[0031] A through hole 141 that communicates the heating space 1S with the outside is formed in the blocking member 14. One end of the through hole 141 opens to the blocking surface 14s, and the other end opens toward the outside. The other end functions as a gas outlet 1Q for leading the target gas generated in the heating space 1S to the gas analyzer 2.

[0032] Further, an insertion hole 142 through which a sample manipulation rod 31 (described later) is inserted is formed in the closing member 14. This insertion hole 142 is formed straight along the tube axial direction, with one end opening to the closing surface 14s and the other end opening toward the outside.

[0033] The furnace body 11 generates a temperature gradient in the heating space 1S along the tube axis direction by being heated by the electric resistor 12. That is, the temperature distribution in the heating space 1S along the tube axis direction is not uniform. Specifically, as shown in Fig. 2, the temperature distribution in the heating space 1S becomes lower toward both ends along the tube axis direction and becomes higher toward the center.

[0034] The electric resistor 12 generates heat when power is supplied from the power supply circuit 12a, thereby heating the furnace body 11. The furnace body 11 may be heated by passing an electric current through the electric resistance furnace to generate resistance heating (Joule heating), in which case the furnace body 11 is made of a metal having electrical conductivity. Alternatively, the container V or sample S contained in the furnace body 11 may be induction heated.

[0035] The gas analyzer 2 analyzes the gas generated in the heating furnace 1 to determine the content of each component contained in the sample S. In this embodiment, for example, the analysis is performed using a non-dispersive infrared absorption method (NDIR method). Specifically, the gas analyzer 2 has a non-dispersive infrared detector (not shown) and detects CO2, CO, SO2, etc. contained in the gas discharged from the gas discharge port 1Q of the heating furnace 1 to determine the content of carbon (C), sulfur (S), etc. contained in the sample S. The gas analyzer 2 of this embodiment performs offset correction using a reference gas such as oxygen, then detects the gas to be analyzed introduced from the gas inlet 1Q, measures the signal intensity over time, and calculates the concentration of each component based on this signal intensity.

[0036] Therefore, the elemental analysis apparatus 100 of this embodiment is characterized by having a sample position adjustment mechanism 3 that can move the sample S and the container V containing it in the furnace body 11 along the tube axial direction while the sample insertion port 1P is closed (i.e., sealed), so that the temperature of the sample S can be changed in a short period of time while the target gas is being analyzed, and a control device 4.

[0037] The sample position adjustment mechanism 3 of this embodiment is provided in the heating space 1S so as to face the sample insertion port 1P, and is configured to be able to push out the sample S inserted into the furnace body 11 to a desired position along the tube axis direction from the gas outlet 1Q side toward the sample insertion port 1P side. Specifically, the sample position adjustment mechanism 3 includes a sample manipulation rod 31 having an operation surface 31s at its tip for pushing out the sample S, and a drive unit (not shown) for driving the sample manipulation rod 31.

[0038] The sample manipulation rod 31 is rod-shaped and penetrates the blocking member 14 along the tube axis direction, and its tip, on which the operation surface 31s is formed, is configured to be always located within the heating space 1S during gas analysis. The sample manipulation rod 31 is made of a metal material with high heat resistance, such as stainless steel. The base end side end of the sample manipulation rod 31 is connected to a drive unit, and the sample manipulation rod 31 is configured to be driven by the drive unit to move forward and backward in a straight line (slide movement) along the tube axis direction. Specifically, the sample manipulation rod 31 includes a rod portion 311 that penetrates the blocking member 14, and an operation portion 312 provided at the tip of the rod portion 311.

[0039] The rod portion 311 has a straight tube shape and moves the operating portion 312 horizontally along the tube axis direction within the heating space 1S. The rod portion 311 is inserted into the insertion hole 142 of the blocking member 14 and is movable forward and backward along the tube axis direction. An airtight structure is formed between the inner peripheral side surface of the insertion hole 142 and the outer peripheral side surface of the rod portion 311, sealed by a sealing member such as an O-ring.

[0040] The rod portion 311 of this embodiment has a double-pipe structure consisting of an outer pipe and an inner pipe arranged concentrically, and an internal space through which a fluid can flow is formed within the inner pipe and the outer pipe (specifically, between the inner surface of the outer pipe and the outer surface of the inner pipe).

[0041] The operation unit 312 is flat and plate-shaped, and is provided so that the entirety of the operation unit 312 is located within the heating space 1S. The operation surface 31s described above is formed on the tip surface of the operation unit 312 facing the sample insertion port 1P so as to intersect (here, perpendicular to) the tube axis direction. The back surface of the tip surface of the operation unit 312 is connected to the tip of the rod portion 311, and as the rod portion 311 moves back and forth, the operation surface 31s of the operation unit 312 moves horizontally along the tube axis direction.

[0042] The operation part 312 has a hollow structure, and an internal space through which a fluid can flow is formed inside the operation part 312. The internal space is configured to communicate with the internal space formed in the rod part 311.

[0043] The driving unit includes an actuator such as an air cylinder, etc. The driving unit moves the rod portion 311 back and forth along the tube axis direction based on a control signal from the control device 4, thereby moving the operation surface 31s to a desired position between the end of the gas outlet 1Q side and the end of the sample inlet 1P side in the heating space 1S.

[0044] The sample position adjustment mechanism 3 is equipped with a cooling mechanism that cools the sample manipulation rod 31 by water cooling. Specifically, the cooling mechanism is equipped with an internal flow path 32a formed inside the sample manipulation rod 31, and a cold water supply mechanism (not shown) that supplies cold water to the internal flow path 32a. Specifically, the internal flow path 32a is formed in each of the rod part 311 and the operation part 312, and is configured to communicate with each other, as shown in FIG. 1. The cold water supplied by the cold water supply mechanism passes through the external piping of the rod part 311 (specifically, passes between the inner peripheral surface of the external piping and the outer peripheral surface of the internal piping) and is poured into the internal space of the operation part 312, and then passes through the internal piping and is returned to the cold water supply mechanism. That is, in this case, the external piping functions as a feed flow path, and the internal piping functions as a return flow path.

[0045] Physically speaking, the control device 4 is a general-purpose or dedicated computer equipped with a CPU, memory, input / output interface, etc. The control device 4 operates the CPU and peripheral devices in cooperation with a predetermined program stored in a predetermined area of ​​the memory, thereby fulfilling at least the functions of a temperature distribution measurement unit 41 that measures the temperature distribution in the furnace body 11, an analysis result acquisition unit 42 that acquires the analysis results of the gas analyzer 2, and an operation control unit 43 that controls the operation of the sample position adjustment mechanism 3, as shown in FIG.

[0046] The temperature distribution measuring unit 41 measures the temperature distribution (also called the temperature profile) along the tube axis direction in the furnace body 11. To be more specific, as shown in FIG. 1, the heating furnace 1 is provided with a plurality of temperature sensors 15 arranged along the tube axis direction for measuring the temperature of the furnace body 11. The temperature distribution measuring unit 41 acquires temperature data indicating the temperature at each measurement position of the furnace body 11 from each temperature sensor 15, and creates temperature distribution data indicating the relationship between the position along the tube axis direction in the furnace body 11 and the temperature based on the temperature data. More specifically, the temperature distribution measuring unit 41 is configured to estimate and calculate the temperature between the measurement positions of the temperature sensors 15 and at positions outside the measurement range by using, for example, an interpolation method, an extrapolation method, a least squares method, or the like. Therefore, this temperature distribution data indicates not only the temperature at each measurement position by the temperature sensor 15, but also the temperature distribution from one end to the other end along the tube axis direction of the furnace body 11. The temperature distribution measuring unit 41 then outputs the created temperature distribution data to the operation control unit 43.

[0047] Specifically, each temperature sensor 15 is a thermocouple, and as shown in Fig. 1, the temperature measuring junction (hot junction) is disposed in the vicinity of (or in contact with) the outer peripheral surface of the furnace body 11. The temperature sensors 15 are disposed symmetrically with respect to the central position in the furnace body 11 along the tube axis direction (specifically, the position in the furnace that is the hottest). In this embodiment, an odd number (five) of temperature sensors 15 are disposed at equal intervals along the tube axis direction, with the middle temperature sensor 15 disposed at the central position of the furnace body 11.

[0048] The analysis result acquisition unit 42 continuously acquires the analysis results of the gas to be analyzed by the gas analyzer 2 in real time, and outputs these to the operation control unit 43. Specifically, the analysis results acquired by the analysis result acquisition unit 42 indicate the signal intensity output when the gas analyzer 2 detects the gas to be analyzed.

[0049] The operation control unit 43 controls the operation of the sample position adjustment mechanism 3 so as to change the heating temperature of the sample S stepwise based on a sequence previously set by the user. This sequence indicates the multiple heating temperature steps and the order of temperature increases in the temperature rise analysis. Specifically, the operation control unit 43 refers to the acquired temperature distribution data and controls the drive unit of the sample position adjustment mechanism 3 so as to position the operation surface 31s of the sample manipulation rod 31 (or the sample S manipulated by this) at a position within the furnace corresponding to the heating temperature set in the sequence.

[0050] Moreover, the operation control unit 43 of this embodiment is configured to proceed with the sequence (i.e., to move the sample S and change the heating temperature) based on the analysis result obtained from the gas analyzer 2. For example, as shown in Fig. 4, the operation control unit 43 may be configured to monitor the time change in signal intensity indicated by the analysis result, and proceed with the sequence when the signal intensity increases, reaches a peak value, and then falls below a predetermined threshold value (e.g., 1% of the peak value).

[0051] The control device 4 also functions as an in-furnace temperature control unit 44. This in-furnace temperature control unit 44 controls the heat generation amount of the electric resistor 12 so that the maximum temperature in the furnace body 11 becomes a predetermined target value. Specifically, this in-furnace temperature control unit 44 acquires temperature distribution data from the temperature distribution measurement unit 41, and controls the power supply circuit 12a so that the maximum temperature indicated by this temperature distribution data becomes the maximum temperature value in the temperature rise analysis set in the above-mentioned sequence.

[0052] Next, the operation of the elemental analysis apparatus 100 of this embodiment will be described with reference to FIG. 5. Here, the temperature of the sample S put into the heating furnace 1 is raised stepwise from a low temperature region (for example, about 200°C) to a high temperature region (for example, about 1000°C) based on a sequence previously set by the user, and the resulting analysis target gas is separated by temperature and led to the analyzer 2 for analysis (i.e., performing a temperature rise analysis). Here, it is assumed that the inside of the heating furnace 1 is sufficiently heated before the start of the analysis, the temperature at the center (the maximum temperature inside the furnace) has reached the maximum temperature set in the sequence (for example, 1000°C), and a temperature gradient is generated such that the temperature becomes lower (for example, 200°C) toward both ends of the furnace body 11. In addition, before the start of the analysis, the temperature distribution in the furnace body 11 is measured by the temperature distribution measurement unit 41, and the position of the sample S is adjusted by the sample position adjustment mechanism 3 based on this measured temperature distribution.

[0053] First, the cover member 131 is moved to the open position to open the sample insertion port 1P, and the user inserts a container V containing a sample S from the sample insertion port 1P using a metal rod or the like, and moves it to the low temperature region (near the end on the gas outlet 1Q side) at the back of the heating space 1S (FIG. 5(a)). Then, the cover member 131 is moved to the closed position to close the sample insertion port 1P. Here, the user operates the operation panel or the like of the elemental analysis device 100 to start the analysis of the sample S. First, a combustion-supporting gas (oxygen, etc.) is supplied from a gas supply port (not shown) into the heating space 1S, and combustion of the sample S (for example, combustion of the surface of the sample S) begins. Then, the analyzer 2 analyzes the analysis target gas generated in the low temperature region (FIG. 5(b)).

[0054] When the signal intensity of the gas to be analyzed output from the analyzer 2 decreases and the analysis in the low temperature region is completed, the temperature of the sample S is raised to a high temperature region (e.g., 1000°C). Specifically, when the intensity signal output from the analyzer 2 reaches a peak value and then falls below a threshold value (e.g., 1% of the peak value), the operation control unit 43 controls the sample position adjustment mechanism 3 based on the measured temperature distribution to move the sample S to a high temperature region (the center of the furnace body 11) in the heating space 1S. More specifically, the operation control unit 43 horizontally moves the sample operation rod 31 along the tube axis direction, thereby pushing the container V toward the sample insertion port 1P side by the pushing surface of the operation unit 312, and moves the container V to the high temperature region in the heating space 1S. Then, the combustion of the sample S (e.g., the combustion inside the sample S) starts here, and the analysis of the gas to be analyzed generated in the high temperature region is performed (FIG. 5(c)).

[0055] Then, when the signal intensity of the gas to be analyzed output from the analyzer 2 decreases and the analysis in the high temperature region is completed, the container V is removed from the sample inlet 1P. Specifically, when the intensity signal output from the analyzer 2 reaches a peak value and then falls below a threshold value (for example, 1% of the peak value), the cover member 131 moves to the open position to open the sample inlet 1P. Then, the operation control unit 43 controls the sample position adjustment mechanism 3, and the sample operating rod 31 pushes the container V toward the sample inlet 1P side, and moves the container V from the sample inlet 1P to the outside of the heating space 1S (FIG. 5(d)). When the next sample is to be subjected to a temperature rise analysis, the user inputs the next sample into the furnace body 11 and repeats the above-mentioned operations.

[0056] According to the elemental analysis apparatus 100 of this embodiment configured as described above, a sample position adjustment mechanism 3 is provided that moves the sample S within the furnace body 11 having a temperature gradient. Therefore, for example, during heating analysis, the temperature of the sample S can be changed in a short time by moving the sample S within the furnace body 11 along the tube axis direction without changing the set temperature of the furnace body 11.

[0057] The present invention is not limited to the above-described embodiment.

[0058] For example, the sample position adjustment mechanism 3 in the above embodiment is not limited to the one equipped with the sample manipulation rod 31. The sample position adjustment mechanism 3 may have any configuration as long as it is configured to change the position of the sample S in the furnace body 11 with the sample insertion port 1P closed.

[0059] In addition, the sample manipulation rod 31 in the above embodiment has a flat plate-shaped operation part 312 at its tip, but is not limited to this. The sample manipulation rod 31 may have any shape as long as it can push out the container V with the operation surface 31s provided at its tip.

[0060] In the embodiment described above, the rod portion 311 of the sample manipulation rod 31 has a double-tube structure, but this is not limiting. Any structure may be used as long as the internal flow path 32a is formed and the structure is water-coolable.

[0061] In the elemental analysis apparatus 100 of the above embodiment, the user uses a metal rod or the like to load the sample S into the low temperature region in the furnace body 11, but this is not limited to the above. The elemental analysis apparatus 100 of other embodiments may be configured to load the sample S into the low temperature region in the furnace body 11 using an autosampler (not shown). In this case, the autosampler may be configured to obtain temperature distribution data created by the temperature distribution measurement unit 41 and move the sample S based on this temperature distribution data.

[0062] In the above embodiment, the operation control unit 43 is configured to proceed with the sequence based on the analysis result obtained from the gas analyzer 2, but this is not limiting, and the operation control unit 43 in other embodiments may be configured to proceed with the sequence based on the heating time. In this case, the user may set in advance the heating temperature and the heating time at that heating temperature.

[0063] The cooling mechanism of the above embodiment is configured to include an internal flow path 32a formed inside the sample manipulation rod 31, and is configured to prevent the seal member provided between the sample manipulation rod 31 and the blocking member 14 from burning by cooling the sample manipulation rod 31, but is not limited to this. The cooling mechanism of other embodiments may be configured to directly water-cool or air-cool the seal member, thereby preventing burning. Also, the seal member may be cooled by forming an internal flow path in the blocking member 14 through which a cooling fluid flows.

[0064] The sample position adjustment mechanism 3 in the above embodiment is configured to push the sample S from the gas outlet 1Q side toward the sample inlet 1P side along the tube axis direction, but is not limited thereto. The sample position adjustment mechanism 3 in another embodiment may be configured to pull the sample S from the sample inlet 1P side toward the gas outlet 1Q side along the tube axis direction. Specifically, as shown in FIG. 6, the sample position adjustment mechanism 3 may have an operating part 312 with a hooking surface 31f that hooks onto the container V. The hooking surface 31f is formed on the back side of the operating surface 31s of the operating part 312. In this case, the operating part 312 is connected to the tip of the rod part 311 so as to form a substantially L-shape. The operating part 312 is configured to move between an operating position that is convex downward with respect to the axis of the rod part 311 and a retracted position that is convex upward with respect to the axis of the rod part 311 by rotating the rod part 311 around its axis. When pulling the container V, the operating part 312, which is in the retracted position, is slid to above the container V, and then the rod part 311 is rotated to move the operating part 312 to the operating position. In this state, the rod part 311 is pulled, whereby the container V can be hooked on the hooking surface 31f and pulled.

[0065] Furthermore, the elemental analysis apparatus 100 of the embodiment described above is configured to measure the temperature distribution every time an analysis is performed, but this is not limited thereto. The elemental analysis apparatus 100 of other embodiments does not need to measure the temperature distribution every time an analysis is performed. For example, the elemental analysis apparatus 100 may store the temperature distribution data created by the temperature distribution measurement unit 41 in advance in a memory, and acquire the stored temperature distribution data when performing an analysis.

[0066] Furthermore, the present invention is not limited to the above-described embodiment, and it goes without saying that various modifications are possible without departing from the spirit of the present invention. [Explanation of symbols]

[0067] 100...Elemental analyzer 1...Heating furnace 11 Furnace body 11a: Opening on one end 1S...Heating space 1P: Sample inlet 1Q Gas outlet 2. Gas analyzer 3. Sample position adjustment mechanism V...container S: Sample

Claims

1. A method for analyzing a sample using an elemental analyzer comprising: a furnace body having a tubular shape with a sample inlet at one end, the furnace body generating a temperature gradient along the axial direction of the tube; and an analyzer for analyzing an analysis target gas generated from the sample heated in the furnace body, the method comprising: Based on temperature data acquired from a plurality of temperature sensors attached to the furnace body along the tube axis direction, temperature distribution data is created before the start of analysis, which indicates a relationship between a position along the tube axis direction in the furnace body and a temperature at the position; An elemental analysis method characterized by referring to the temperature distribution data during analysis of the sample, and changing the temperature of the sample by moving the sample in the furnace body along the tube axis direction using a sample position adjustment mechanism arranged in the furnace body.

2. 2. The elemental analysis method according to claim 1, further comprising a temperature rise analysis in which the temperature of the sample is raised stepwise by gradually moving the sample from a relatively low temperature region to a relatively high temperature region within the furnace body during analysis of the sample.

3. 3. The elemental analysis method according to claim 2, wherein a plurality of said samples are sequentially charged into said furnace body, and said temperature rise analysis is performed successively.

4. 4. The elemental analysis method according to claim 1, wherein the temperature of the sample is changed by moving the sample in the furnace body along the tube axis direction while the sample insertion port is closed.

5. a furnace body having a tubular shape with a sample inlet at one end and generating a temperature gradient along the axial direction of the tube; an analyzer for analyzing a target gas generated from the sample heated in the furnace body; A plurality of temperature sensors are attached to the furnace body along the tube axis direction; a temperature distribution measuring unit that creates temperature distribution data indicating a relationship between a position along the tube axis direction in the furnace body and a temperature at the position based on temperature data acquired from the plurality of temperature sensors; a sample position adjustment mechanism provided within the furnace body and capable of moving the sample within the furnace body along the tube axis during analysis of the sample.

6. 6. The elemental analysis apparatus of claim 5, wherein the sample position adjustment mechanism is provided at a position opposite the sample inlet in the furnace body and is configured to be able to push the sample in the furnace body toward the sample inlet along the tube axis direction.

7. Further, a blocking member is provided to block the opening at the other end of the furnace body, The sample position adjustment mechanism includes: a sample manipulation rod that penetrates the blocking member along the tube axial direction and has an operation surface at a tip end for pushing out the sample; 7. The elemental analyzer according to claim 5, further comprising a drive unit that moves the sample manipulation rod back and forth along the tube axis.

8. 8. An elemental analyzer according to claim 7, wherein said sample manipulation rod is provided so that its tip is always positioned within said furnace body during analysis.

9. the sample position adjustment mechanism includes a cooling mechanism for cooling the sample manipulation rod, 9. The elemental analyzer according to claim 7, wherein the cooling mechanism comprises an internal flow passage formed in the sample manipulation rod, and a cold water supply mechanism that supplies cold water to the internal flow passage.

10. 10. The elemental analyzer according to claim 7, wherein the closing member is formed with a gas outlet port for leading the gas to be analyzed generated in the furnace body to the analyzer.

11. The elemental analysis apparatus according to any one of claims 5 to 10, wherein the sample position adjustment mechanism is configured to be able to move the sample in the furnace body along the tube axis direction when the sample insertion port is closed.

12. a furnace body having a tubular shape with a sample inlet at one end and generating a temperature gradient along the axial direction of the tube; an analyzer for analyzing a target gas generated from the sample heated in the furnace body; a sample position adjustment mechanism capable of moving the sample in the furnace body along the tube axis during analysis of the sample; a blocking member for blocking an opening at the other end of the furnace body, The sample position adjustment mechanism includes: a sample manipulation rod that penetrates the blocking member along the tube axis direction and has a manipulation surface at a tip end for pushing out the sample; a drive unit that moves the sample manipulation rod back and forth along the tube axis; the sample position adjustment mechanism includes a cooling mechanism for cooling the sample manipulation rod, The cooling mechanism includes an internal flow path formed in the sample manipulation rod, and a cold water supply mechanism that supplies cold water to the internal flow path.

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