JP5811994B2 - Sample heating device and element analyzer - Google Patents

Description

  The present invention relates to a sample heating device and an element analyzer, and more particularly, to a sample heating device and an element analyzer that perform a pretreatment for heating a sample such as a liquid or a solid on a sample boat.

  There is a sample heating device that performs a pretreatment for heating a sample such as a liquid or a solid on a sample boat (see, for example, Patent Document 1). Such a sample heating device is used, for example, for measuring the carbon content in a sample.

  FIG. 5 is a schematic configuration diagram of a conventional sample heating apparatus. FIG. 6 is a schematic top view, side view, and front view for explaining the configuration of the sample boat holder used in the sample heating apparatus.

  Oxygen serving as a carrier gas and a combustion supporting gas is constantly flowing at a constant flow rate in the internal space 103 of the sample introduction unit 101. The cover 105 is opened, and the sample boat 107 containing the sample is placed on the sample boat holder 109. Thereafter, the cover 105 is closed. The sample boat holder 109 is fixed to the sample boat moving rod 111.

  A combustion tube 113 is connected to the internal space 103 of the sample introduction unit 101. An oxidation catalyst 115 is disposed inside the combustion tube 113. The combustion tube 113 is heated to a predetermined temperature by the heating furnace 117.

  The sample boat 107 is moved into the combustion tube 113 together with the sample boat holder 109 by operating the sample boat moving rod 111. The sample stored in the sample boat 107 is heated in the combustion tube 113. Carbon in the sample is oxidized and decomposed to generate carbon dioxide. The generated carbon dioxide is guided to the carbon dioxide detector together with the carrier gas. The carbon dioxide detector measures the amount of carbon dioxide generated.

Japanese Patent No. 2531427

  When the sample boat 107 is disposed in the internal space 103 of the sample introduction unit 101, the cover 105 is opened. At this time, the air flows into the internal space 103. The atmosphere contains carbon dioxide. During sample measurement, after the sample boat 107 is placed in the internal space 103 and before being moved into the combustion tube 113, carbon dioxide caused by the inflow of air is first removed from the internal space 103 by the carrier gas flow. There must be. Therefore, a waiting time is required after the sample boat 107 is arranged in the internal space 103.

  This waiting time is, for example, 120 seconds. During the standby time, the sample boat 107 receives radiant heat from the combustion tube 113 side. The distance between the sample boat 107 and the center of the heating furnace 117 is only about 25 cm, for example. The radiant heat raises the temperature of the sample boat 107 and the sample accommodated therein. If the sample housed in the sample boat 107 contains a highly volatile carbon compound such as a lower alcohol, a part of the sample volatilizes from the sample due to the radiant heat. As a result, there is a problem that the measured value becomes lower than the true value.

  Therefore, the present invention reduces the temperature rise of the sample in the sample boat due to the radiant heat from the combustion tube side when the sample boat is arranged at the sample boat installation position in the internal space of the sample introduction unit. It is the purpose.

  The sample heating apparatus according to the present invention is connected to an internal space to which a carrier gas is supplied, a sample introduction part having a sample boat entrance / exit opening / closing mechanism, and the internal space of the sample introduction part, and carrier gas is supplied from the internal space. An inflowing combustion tube, a heating furnace for heating the combustion tube, and a boat operation mechanism for moving a sample boat arranged at a sample boat installation position in the internal space of the sample introduction unit into the combustion tube And a heat shielding plate for concealing the entire sample boat when viewed from the combustion tube side when the sample boat is disposed at least at the sample boat installation position.

  In the sample heating apparatus of the present invention, the boat operating mechanism includes a sample boat holder on which the sample boat is mounted, and the heat shielding plate is located at a position closer to the combustion tube than the mounting position of the sample boat. Can be given as examples.

  Further, in the sample heating apparatus of the present invention, the heat shield plate is viewed from the combustion tube side and the sample boat is located at a radiation heat shield position where the sample boat is hidden, and the sample boat is viewed from the combustion tube side. An example may further include a heat shielding plate operating mechanism for moving between the sample boat exposure position where the sample boat is exposed at the installation position.

  The element analyzer according to the present invention flows out together with the carrier gas from the sample heating device of the present invention, a carrier gas supply unit for supplying a carrier gas to the sample heating device, and the combustion tube of the sample heating device. A detector for detecting a target component contained in the sample contained in the sample boat.

  The sample heating apparatus of the present invention is provided with a heat shielding plate for concealing the entire sample boat when viewed from the combustion tube side at least when the sample boat is arranged at the sample boat installation position. As a result, the sample heating device of the present invention increases the temperature of the sample in the sample boat due to the radiant heat from the combustion tube side when the sample boat is disposed at the sample boat installation position in the internal space of the sample introduction unit. Can be reduced.

  In the sample heating apparatus of the present invention, the sample boat operating mechanism includes a sample boat holder on which the sample boat is mounted, and the heat shielding plate is provided on the sample boat holder at a position closer to the combustion tube than the mounting position of the sample boat. By doing so, the heat shielding plate can be arranged with a simple structure.

  Further, in the sample heating device of the present invention, the heat shield plate includes a radiation heat shielding position where the sample boat at the sample boat installation position is hidden when viewed from the combustion tube side, and a sample boat at the sample boat installation position as viewed from the combustion tube side. If a heat shield plate operating mechanism for moving between the exposed position of the sample boat is further provided, the temperature rise of the sample in the sample boat due to radiant heat from the combustion tube side is reduced. be able to.

  Since the element analyzer of the present invention uses the sample heating apparatus of the present invention, the sample boat caused by radiant heat from the combustion tube side when the sample boat is arranged at the position of the sample boat in the internal space of the sample introduction unit The temperature rise of the inner sample can be reduced, and the measurement accuracy can be improved. For example, even if the sample contains a highly volatile carbon compound, the element analyzer of the present invention can prevent the measured value from becoming a low value.

It is a schematic block diagram for demonstrating one Example of a sample heating apparatus. It is the schematic top view, side view, and front view for demonstrating the structure of a sample boat holder and a heat shielding board. It is a schematic block diagram for demonstrating one Example of an element analyzer. FIG. 7 is a schematic configuration diagram for explaining another example of the sample heating apparatus and a cross-sectional view showing an enlarged cross section at the A-A ′ position. It is a schematic block diagram of the conventional sample heating apparatus. It is the schematic top view, side view, and front view for demonstrating the structure of the sample boat holder used for a sample heating apparatus.

  FIG. 1 is a schematic configuration diagram for explaining an embodiment of a sample heating apparatus. FIG. 2 is a schematic top view, side view, and front view for explaining the configuration of the sample boat holder and the heat shielding plate.

The sample heating device 1 includes a sample introduction unit 3, a combustion tube 5, a heating furnace 7, a boat operation mechanism 9, and a heat shielding plate 11.
The sample introduction unit 3 includes an internal space 13 to which a carrier gas is supplied and a sample boat entrance opening / closing mechanism 15.

The combustion tube 5 is connected to the internal space 13 of the sample introduction unit 3. The combustion tube 5 is made of, for example, quartz glass. An oxidation catalyst 17 is disposed inside the combustion pipe 5. The carrier gas flows from the internal space 13 into the combustion pipe 5.
The heating furnace 7 heats the combustion tube 5 to a predetermined temperature.

  The boat operating mechanism 9 includes a sample boat moving rod 19 and a sample boat holder 21 on which the sample boat 23 is mounted. The boat operation mechanism 9 is for moving the sample boat 23 disposed at the sample boat installation position in the internal space 13 of the sample introduction unit 3 into the combustion tube 5. The sample boat 23 is made of, for example, ceramic.

  The heat shielding plate 11 is for hiding the entire sample boat 23 when viewed from the combustion tube 5 side at least when the sample boat 23 is disposed at the sample boat installation position. For example, the heat shielding plate 11 has an area larger than the front projected area of the sample boat 23 as viewed from the combustion tube 5 side. The heat shielding plate 11 is located more than the mounting position of the sample boat 23 so that the sample boat 23 is hidden by the heat shielding plate 11 when viewed from the combustion tube 5 side when the sample boat 23 is disposed at the sample boat installation position. The sample boat holder 21 is provided at a position on the combustion tube 5 side.

  For example, the sample boat holder 21 is formed by bending a thin stainless steel plate having a thickness of 0.5 mm (millimeters). The tip portion of the sample boat holder 21 has a substantially disk shape with a diameter of 18 mm, for example, and constitutes the heat shield plate 11. The inner diameter of the combustion tube 5 is 24 mm, for example. Therefore, a gap of 3 mm is secured between the inner wall surface of the combustion tube 5 and the outer peripheral edge of the heat shielding plate 11, and the flow of the carrier gas is not hindered. Thus, the heat shielding plate 11 is formed with a size that does not hinder the flow of the carrier gas when inserted into the combustion tube 5. The base end portion of the sample boat holder 21 is fixed to the sample boat moving rod 19 by screws, for example.

  The sample boat entrance opening / closing mechanism 15 is opened, and the sample boat 23 is mounted on the sample boat holder 21 arranged at the sample boat installation position. Thereafter, the sample boat doorway opening / closing mechanism 15 is closed. Since the heat shielding plate 11 exists between the sample boat 23 and the combustion tube 5, radiant heat from the combustion tube 5 side toward the sample boat 23 side is blocked by the heat shielding plate 11. Thereby, the temperature rise of the sample in the sample boat 23 resulting from the radiant heat from the combustion tube 5 side is reduced compared with the case where the heat shielding plate 11 is not provided.

  In this embodiment, the heat shielding plate 11 is formed integrally with the sample boat holder 21. However, in the sample heating apparatus of the present invention, the heat shielding plate may be formed separately from the sample boat holder. . In that case, the method for attaching the heat shielding plate to the sample boat holder is not particularly limited.

  FIG. 3 is a schematic configuration diagram for explaining an embodiment of the element analyzer. In this example, the element analyzer of the present invention was applied to a TOC (Total Organic Carbon) meter.

  The TOC meter includes a sample heating device 1 for TC (Total Carbon) measurement and a sample heating device 25 for IC (Inorganic Carbon) measurement. The sample heating device 1 and the sample heating device 25 are connected in series.

  The sample heating apparatus 1 for TC measurement is the same as that described with reference to FIG. The furnace temperature of the heating furnace 7 is set to 900 ° C., for example. A carrier gas (oxygen) that also serves as a combustion support gas is continuously introduced into the internal space 13 from the carrier gas supply unit 27 at a flow rate of, for example, 500 mL / min (milliliter / min). The carrier gas flows through the sample heating device 1, the cooling pipe 29, the dehumidifying unit 31, the sample heating device 25, and the dehumidifying unit 31 again to the detector 33 including, for example, a non-dispersive infrared gas analyzer (NDIR). Reference numerals 35 and 37 are cooling fans.

  In the sample heating apparatus 1 for TC measurement, a sample boat 23 in which a sample is stored is inserted into the internal space 13 from the sample boat entrance / exit opening / closing mechanism 15 of the sample introduction unit 3 and mounted on the sample boat holder 21. After the sample boat entrance opening / closing mechanism 15 is closed, for example, a waiting time of 120 seconds is provided. As a result, the atmosphere that has flowed into the analyzer flow path via the internal space 13 when the sample boat doorway opening / closing mechanism 15 is opened and closed is completely discharged out of the analyzer. After confirming that the baseline of the detector 33 is stable, the sample boat 23 is inserted into the combustion tube 5 by operating the sample boat moving rod 19. The configuration may be such that the confirmation of the baseline of the detector 33 is omitted and the sample boat 23 is inserted into the combustion pipe 5 after a predetermined time has elapsed since the sample boat entrance / exit opening / closing mechanism 15 is closed. .

  The organic matter in the sample evaporates or decomposes in the combustion tube 5 and reaches the oxidation catalyst 17 together with the carrier gas containing oxygen, and all the organic matter is oxidized to carbon dioxide gas by the action of the catalyst. This carbon dioxide gas is guided to the detector 33 through the cooling pipe 29, the dehumidifying unit 31, the sample heating device 25, and the dehumidifying unit 31 together with the carrier gas, and the TC in the sample is measured. The detector 33 made of NDIR captures the inflowing carbon dioxide gas as a peak on the baseline, and measures the amount of carbon dioxide from the area.

  The sample heating device 25 for IC measurement basically has the same configuration as the sample heating device 1 for TC measurement. In the sample heating device 25 for IC measurement, the same reference numerals as those of the sample heating device 1 for TC measurement are attached to the parts that perform the same functions as the sample heating device 1 for TC measurement.

  In the sample heating device 25 for IC measurement, the sample boat 23 in which the sample is accommodated is inserted into the internal space 13 from the sample boat entrance / exit opening / closing mechanism 15 of the sample introduction unit 3 and mounted on the sample boat holder 21. After the sample boat entrance opening / closing mechanism 15 is closed, for example, a waiting time of 120 seconds is provided. After the waiting time has elapsed, an inorganic acid is added from the acid dispenser 39 to the sample in the sample boat 23. As the acid, phosphoric acid which is a non-volatile acid is suitable. After confirming that the baseline of the detector 33 is stable, the sample boat 23 is inserted into the combustion tube 5 by operating the sample boat moving rod 19.

  In the sample heating device 25 for IC measurement, the heating temperature of the heating furnace 7 is relatively lower than that of the heating furnace 7 of the sample heating device 1 for TC measurement, for example, 200 ° C. Here, the IC component in the sample The reaction with the acid is promoted, and further, the carbon dioxide converted and produced by the reaction is rapidly extracted into the gas phase under the action of stirring and expelling by heating. The extracted carbon dioxide gas is guided to the detector 33 through the dehumidifying unit 31 together with the carrier gas, and the IC in the sample is measured similarly to the TC measurement. The carrier gas is supplied to the IC measurement sample heating device 25 from the carrier gas supply unit 27 through the TC measurement sample heating device 1, the cooling pipe 9, and the dehumidifying unit 31.

  Pure water added with 10 mg C propanol is used as a sample boat holder (see FIGS. 1 and 2) having a heat shielding plate 11 and a conventional sample boat holder 109 not having the heat shielding plate 11 (FIGS. 5 and 6). Table 1 shows the result of TC measurement using

  As can be seen from Table 1, when the heat shield plate 11 acts effectively, volatilization of propanol during the standby time was suppressed, and as a result, a correct measurement value could be obtained.

  FIG. 4 is a schematic configuration diagram for explaining another embodiment of the sample heating apparatus and a cross-sectional view showing an enlarged cross section at the A-A ′ position. 4, parts having the same functions as those in FIG. 1 are denoted by the same reference numerals, and descriptions thereof are omitted.

  The sample boat holder 41 is the same as the sample boat holder 109 shown in FIG. This embodiment further includes a heat shield plate 43, a heat shield plate accommodation space 45, and a heat shield plate operating mechanism 47, as compared with the embodiment shown in FIG.

  The heat shielding plate 43 is for hiding the entire sample boat 23 when viewed from the combustion tube 5 side at least when the sample boat 23 is disposed at the sample boat installation position. For example, the heat shielding plate 11 has an area larger than the front projected area of the sample boat 23 as viewed from the combustion tube 5 side. The shape of the heat shielding plate 43 is, for example, a substantially disk shape having a thickness of 0.5 mm and a diameter of 18 mm. The inner diameter of the combustion tube 5 is 24 mm, for example. The size and shape of the heat shielding plate 43 are designed so that the flow of the carrier gas is not blocked when the heat shielding plate 43 is disposed at the radiation heat shielding position.

  The heat shield plate accommodation space 45 communicates with the internal space 13 and is provided inside the sample introduction unit 3. The heat shield plate operating mechanism 47 is configured so that when viewed from the combustion tube 5 side, the heat shield plate 43 is exposed to the radiation heat shield position (position on the internal space 13 side) where the sample boat 23 at the sample boat installation position is hidden, and from the combustion tube 5 side. It is for moving between the sample boat exposure position (position on the heat shield plate accommodation space 45 side) where the sample boat 23 at the sample boat installation position is exposed.

  When the heat shield plate 43 is moved from the sample boat exposure position to the radiant heat shield position by the operation of the heat shield plate operation mechanism 47, the sample boat 23 is hidden by the heat shield plate 47 when viewed from the combustion tube 5 side. Thereby, the temperature rise of the sample in the sample boat 23 resulting from the radiant heat from the combustion tube 5 side can be reduced.

  When the heat shield plate 43 is moved from the sample boat exposure position to the radiant heat shield position by operating the heat shield plate operation mechanism 47, the sample boat 23 is exposed as viewed from the combustion tube 5 side. As a result, the sample boat 23 can be moved into the combustion tube 5.

  In this embodiment, the diameter of the heat shield plate 43 is smaller than the inner diameter of the combustion tube 5, but if the heat shield plate 43 is disposed at a location where the internal dimension of the internal space 13 is larger than the inner diameter of the combustion tube 5. It is also possible to make the size of the heat shielding plate 43 larger than the inner diameter of the combustion tube 5.

  In this embodiment, the sample boat holder 21 (see FIG. 2) provided with the heat shield plate 11 is used instead of the sample boat holder 41, and both the heat shield plate 43 and the heat shield plate 11 are used. You may make it shield the radiant heat from the combustion pipe 5 side.

  Although the embodiments of the present invention have been described above, the configurations, arrangements, numerical values, and the like in the embodiments are merely examples, and the present invention is not limited thereto, and the scope of the present invention described in the claims. Various modifications can be made within.

  For example, the sample heating device and the element analyzer of the present invention can be applied to an element analyzer other than the TOC meter.

  The sample heating apparatus of the present invention is connected to an internal space to which a carrier gas is supplied, a sample introduction part having a sample boat entrance / exit opening / closing mechanism, and the internal space of the sample introduction part, and the carrier gas flows in from the internal space A combustion tube for heating, a heating furnace for heating the combustion tube, and a boat operation mechanism for moving a sample boat arranged at a sample boat installation position in the internal space of the sample introduction portion into the combustion tube; As long as the sample heating apparatus is provided with any of the above, it can be applied to any configuration.

  The element analyzer of the present invention includes such a sample heating device, a carrier gas supply unit for supplying a carrier gas to the sample heating device, and the carrier gas flowing out from the combustion tube of the sample heating device, Any element analyzer having a detector for detecting a target component contained in a sample housed in a sample boat can be applied.

  For example, the sample heating apparatus and the element analyzer of the present invention can be applied to an element analyzer that measures carbon, hydrogen, nitrogen, sulfur and the like contained in a sample. Examples of the liquid sample include environmental water such as river water, lake water, marine water, rain water, and ground water, and liquid samples generated in various tests and researches. Examples of solid samples include soil, sediment, agricultural and livestock products, and solid samples generated in various tests and research. However, measurement components, liquid samples, and solid samples targeted by the sample heating device and the element analyzer of the present invention are not limited to these.

  In the said Example, although the shape of the heat shielding board 11 is a substantially disk shape, the shape of the heat shielding board in the sample heating apparatus of this invention is not limited to this. In the sample heating apparatus of the present invention, the shape of the heat shielding plate is such that at least the sample boat can be hidden when viewed from the combustion tube side when the sample boat is disposed at the sample boat installation position. Any shape can be used.

  In the above embodiment, the boat operation mechanism 9 is constituted by the sample boat moving rod 19 and the sample boat holder 21, but the boat operation mechanism in the sample heating apparatus of the present invention is not limited to this. In the sample heating apparatus of the present invention, the configuration of the boat operating mechanism may be any configuration as long as the sample boat can be moved into the combustion tube.

  In the said Example, although the heat shielding board operation mechanism 47 is comprised by the rod-shaped thing, the heat shielding board operation mechanism in the sample heating apparatus of this invention is not limited to this. In the sample heating apparatus of the present invention, the configuration of the heat shield plate operating mechanism is any configuration as long as the heat shield plate can be moved between the radiation heat shield position and the sample boat exposure position. Also good. For example, the heat shield plate operating mechanism includes an elastic body that supports the heat shield plate disposed at the radiant heat shield position, and is elastic when pressed by the boat operating mechanism when the boat is moved to the combustion tube side of the sample boat. Even if the body is deformed, the heat shield plate is moved to the sample boat exposure position, and the heat shield plate is moved to the radiation heat shield position by the restoring force of the elastic body when the sample boat returns to the sample introduction part side. Good.

DESCRIPTION OF SYMBOLS 1,25 Sample heating apparatus 3 Sample introduction part 5 Combustion tube 7 Heating furnace 9 Sample boat operation mechanism 11, 43 Heat shielding board 13 Internal space 15 Sample boat entrance opening / closing mechanism 21, 41 Sample boat holder 23 Sample boat 27 Carrier gas supply part 33 Detector 47 Thermal shield operating mechanism

Claims (4)

A sample introduction part having an internal space to which a carrier gas is supplied, and a sample boat entrance opening and closing mechanism;
A combustion pipe connected to the internal space of the sample introduction section and into which a carrier gas flows from the internal space;
A heating furnace for heating the combustion tube;
A boat operating mechanism for moving a sample boat arranged at a sample boat installation position in the internal space of the sample introduction unit into the combustion pipe;
A sample heating apparatus comprising: a heat shielding plate for concealing the entire sample boat when viewed from the combustion tube side when the sample boat is disposed at least at the sample boat installation position. The boat operation mechanism includes a sample boat holder on which the sample boat is mounted,
2. The sample heating apparatus according to claim 1, wherein the heat shielding plate is provided in the sample boat holder at a position closer to the combustion tube than a mounting position of the sample boat.   A radiation heat shielding position where the sample boat at the sample boat installation position is hidden when the heat shield plate is viewed from the combustion tube side, and the sample boat at the sample boat installation position is exposed when viewed from the combustion tube side. The sample heating apparatus according to claim 1, further comprising a heat shielding plate operating mechanism for moving between the exposed position of the sample boat. The sample heating device according to any one of claims 1 to 3,
A carrier gas supply unit for supplying a carrier gas to the sample heating device;
An element analyzer comprising: a detector for detecting a target component contained in a sample accommodated in the sample boat, which flows out together with a carrier gas from the combustion tube of the sample heating device.

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