JP4560058B2 - Contained oxygen analyzer and contained oxygen analysis method - Google Patents

Description

The present invention relates to a contained oxygen analyzer and method , and more specifically, as a measurement target sample, for example, by removing an oxide film on a sample surface in measurement of a trace amount of oxygen of a metal (particularly steel), a very small amount is contained. The present invention relates to a contained oxygen analyzer and a contained oxygen analyzing method capable of measuring oxygen.

For example, as a quantitative analysis method for oxygen contained in steel, a combination of a melt extraction method in an inert gas, an infrared absorption method, and a thermal conductivity method is generally used. In this inert gas melting extraction method, infrared absorption method and thermal conductivity method, a graphite crucible with the sample to be measured is placed in a heating furnace, and the steel as the sample to be measured is heated while supplying the inert gas. The carbon monoxide or carbon dioxide that is melted and then generated is analyzed by, for example, an infrared gas analyzer.
JP-A-6-148170

  By the way, in order to accurately detect a small amount of oxygen in a sample to be measured such as steel, oil or dirt (hereinafter referred to as deposits) or oxide film adhering to the surface of the sample to be measured is removed. It is necessary to remove in advance. And in order to remove the deposit | attachment adhering to the surface of a measuring object sample, the pre-processing was performed by means, such as heating a sample at 400 to 600 degreeC for about 10 minutes.

  FIG. 13 shows an example of a conventional method for analyzing oxygen content. The method for removing the oxide film shown in FIG. 13 is the method described in Patent Document 1, and FIG. 13 (A) shows the temperature change in the carbon furnace (graphite crucible) with the progress of the oxygen analysis. FIG. 13B shows a change in signal amount detected by the infrared gas analyzer.

In FIG. 13, first, the carbon furnace is preheated at a high temperature such as 3000 ° C. between time points Tp _{11 and} Tp ₁₂ . Then, at time Tp _13, a measurement target sample dropped into a graphite crucible preheating is finished, during the time Tp ₁₄ Tp _15, the measured sample temperature below the melting point (e.g., 900 ° C. to 1400 ° C. range ) To reduce the surface oxide film. Then, after that, the temperature of the carbon furnace is raised to, for example, 1400 ° C. or higher (specifically, 2400 ° C.), and the oxygen content of the sample to be measured is analyzed.

  FIG. 14 shows another example of another oxygen content analysis method. FIG. 14 (A) shows the temperature change in the carbon furnace as the oxygen content analysis proceeds, and FIG. 14 (B) shows the infrared gas. The change of the signal amount detected by the analyzer is shown.

In the method shown in FIG. 14, first, the graphite crucible is preheated between time points Tp _{21 and} Tp ₂₂ , and then the sample to be measured is put into the graphite crucible at time point Tp ₂₃ . Next, at time points Tp _{24 to} Tp ₂₅ , the surface oxygen is removed by heating the sample to be measured to, for example, 1050 ° C. in the graphite inert gas. Then, the sample to be measured is cooled to approximately room temperature in the inert gas, and at time Tp ₂₆ , the sample to be measured is taken out into the atmosphere and oxidized.

Next, after the graphite crucible is preheated again between time points Tp ₂₇ and Tp _28, the sample to be measured is put into the graphite crucible at time point Tp ₂₉ . Then, at time Tp ₃₀ Tp _31, in graphite inert gas, the sample to be measured with again remove the surface oxygen by heating for example to 1050 ° C., the amount of signal Sp ₂₁ at this time, oxide film Measure the amount of oxidation. Then, the sample to be measured is cooled to approximately room temperature in the inert gas, and at time Tp ₃₂ , the sample to be measured is taken out into the atmosphere and oxidized again.

Furthermore, after pre-heating the graphite crucible for the third time between time points Tp ₃₃ and Tp ₃₄ , a metal solvent is introduced into the graphite crucible at time point Tp _{35 and the} interior of the graphite crucible is heated to, for example, 2400 ° C. Create a metal bath of metal solvent in the graphite crucible. At time Tp _{3 6} , the signal amount Sp ₂₂ of the gas generated by putting the measurement target sample into the graphite crucible is measured. As a result, the amount of oxidation of the oxide film determined from the signal amount is subtracted from the total amount of oxygen determined (Sp ₂₂ -Sp ₂₁ ), thereby determining this as the oxygen content (bulk oxygen) of the sample to be measured.

However, the conventional oxygen analysis method as shown in FIG. 13 is generated from a graphite crucible when the temperature of the graphite crucible is raised from a preheating temperature of 900 to 1400 ° C. to 1400 ° C. or higher (specifically, 2400 ° C.). Since the signal Sp ₁₁ due to the carbon monoxide gas to be increased increases, the influence of the fluctuation of the signal Sp ₁₁ is added to the measured signal amount Sp ₁₃ , and the signal due to the oxygen contained in the sample to be measured There was a problem that the size of Sp ₁₂ could not be obtained accurately.

In particular, as the amount of oxygen contained in the sample to be measured is extremely small, an increase in the signal Sp11 due to the carbon monoxide gas generated from the graphite crucible has a large effect. Therefore, the analysis result cannot be suppressed to a variation of 0.5 ppm or less at maximum. That is, the conventional oxygen analysis method as shown in FIG. 13 cannot analyze a very small amount of oxygen contained.

Further, the conventional oxygen analysis method as shown in FIG. 14 has to measure the surface oxidized oxygen twice, and it is inevitable that the measurement takes a long time. In addition to this, the oxygen analysis method performs subtraction (Sp ₂₂ -Sp ₂₁ ) on the premise that the amount of the first surface oxygen is the same as the amount of the second surface oxygen. In both cases, it was inevitable that the two would fluctuate depending on the time of exposure to the atmosphere and other conditions. In other words, even in this example, the variation in surface oxidation could not be suppressed to a maximum of 0.5 ppm or less with respect to the analysis value when measuring a very small amount of oxygen content of about 2.9 μg / g.

  The present invention has been made in consideration of the above-mentioned matters, and its purpose is to analyze the amount of oxygen contained in a metal (especially steel) as a measurement target sample with high accuracy. The object is to provide an apparatus and a method for analyzing oxygen content.

In order to achieve the above object, the oxygen analyzer of the first invention is provided with a graphite crucible installed in a space cut off from the outside air in the analysis furnace, and a metal bath is introduced into the graphite crucible. A sample holder and a sample holder for loading a sample to be measured are provided above the analysis furnace, respectively.
Preliminarily reduce the oxide film on the surface by heating the sample to be measured put in from the sample holder to a temperature below the melting point in the graphite crucible,
Temporarily by the sample extraction means in a condition in which the the pre-reduced measured sample, wherein the sample holder or we throw input metal baths coexist in a graphite crucible, the only constant target sample measured was isolated from the atmosphere The metal bath remaining in the graphite crucible is heated and dissolved, and then the sample to be measured held by the sample take-out means is put into the graphite crucible while being isolated from the atmosphere. A dissolved oxygen analyzer for analyzing the oxygen content of the sample to be measured,
The sample take-out means is composed of a rod body that slides in the vertical direction so as to be airtight against the outside air, and the rod body has a lower tip for taking out and holding the sample to be measured, while the rod An actuator for sliding the body in the vertical direction is provided. (Claim 1)

  Therefore, by using the oxygen analyzer, the oxide film adhering to the surface of the sample to be measured is completely reduced, and only the contained oxygen (bulk oxygen) inside the sample to be measured is accurately measured. Can do. In addition, since the graphite crucible is not heated step by step, the amount of oxygen contained in trace amounts can be measured while maintaining a constant temperature in the analytical furnace, and the gas generated from the graphite crucible can be used as a baseline. The accuracy can be improved by removing them.

  Furthermore, by preheating the sample to be measured in the analysis furnace, the apparatus configuration can be simplified and downsized. Moreover, since the volume of the part which forms the state isolated from air | atmosphere becomes small, the isolation state from air | atmosphere can be formed at low cost.

When the sample to be measured is steel, and the rod body has a magnetic force induction portion at the lower end portion thereof that can extract the steel from the graphite crucible by magnetic attraction (Claim 2), the steel is graphite crucible. Can be easily taken out from the inside, and the device configuration is simplified.

Wherein a measured sample is steel, if having a magnetic force part for the rod is a removable steel in black lead crucible at its lower tip from a graphite crucible by adsorption by magnetic force (claim 3) , Without making the magnetic force generated from the magnetic force acting part formed at the lower tip of the rod body darkly strong, it is possible to reliably adsorb steel and save energy, and there is no possibility of affecting the operation of surrounding equipment at all . Moreover, since the operation of taking out the steel from the graphite crucible by magnetic force adsorption is sufficient only by sliding the rod up and down, automation can be easily achieved.

  In addition, although the structure can be simplified by forming a magnetic force action part with a permanent magnet and manufacturing cost can be reduced by that much, automatic control can be facilitated by using this as an electromagnet.

The oxygen analysis method according to the second aspect of the present invention provides a sample holder and a measurement object for providing a graphite crucible installed in a space that is shielded from the outside air in the analysis furnace, and pouring a metal bath into the graphite crucible. A sample holder for loading the sample is provided above the analysis furnace, and
Preliminarily reduce the oxide film on the surface by heating the sample to be measured put in from the sample holder to a temperature below the melting point in the graphite crucible,
Temporarily by the sample extraction means in a condition in which the the pre-reduced measured sample, wherein the sample holder or we throw input metal baths coexist in a graphite crucible, the only constant target sample measured was isolated from the atmosphere The graphite crucible in which the metal bath is left is heated above its melting point and below its boiling point, and the oxygen contained therein is reduced by dissolving the metal bath,
In a state where the amount of gas generated from the heated graphite crucible is stable, this amount of gas is obtained as a reference value, and while maintaining the temperature of the graphite crucible at this time, the sample to be measured held by the sample take-out means is obtained. When performing a series of analysis operations in which the oxygen content of the sample to be measured is analyzed from the amount of gas generated by heating by melting it in a graphite crucible while being isolated from the atmosphere,
The sample take-out means is characterized by using a rod body that slides up and down by an actuator so as to be airtight with respect to the outside air, and has a lower tip for taking out and holding the sample to be measured. (Claim 5)

  That is, remove the surface oxide film of the sample to be measured in advance and keep it isolated from the atmosphere, while maintaining the gas amount generated from the graphite crucible in which the metal bath is dissolved in a stable state. Since the measurement target sample from which the surface oxide film has been removed can be introduced into the graphite crucible, the amount of gas generated due to the trace amount of oxygen contained in the measurement target sample is calculated from the total measurement value. It can be accurately obtained by subtracting the reference value.

  According to the oxygen analyzer and oxygen analysis method of the present invention, a small amount of oxygen contained in the sample to be measured without being affected by the oxide film generated on the surface of the sample to be measured while having a simple configuration. The quantity can be quantitatively analyzed with high accuracy.

The three reference example before explaining the embodiments of the invention will be described with reference to the drawings. 1 to 3 show a configuration of a contained oxygen analyzer 1 of a first reference example. The sample S to be measured is, for example, steel, and the oxygen analyzer 1 measures a small amount of oxygen contained in the sample. FIG. 4 is a diagram showing a modification of FIG.

As shown in FIG. 1, the graphite crucible 2 for inserting the measuring object sample S inside the containing aerobic analyzer 1 and analyzes furnace 3 having a (hereinafter, also referred to as graphite furnace 2), the measuring object sample S A pre-reduction furnace 4 for pre-reducing the oxide film on the surface by heating at a temperature below the melting point, a communication passage 5 for connecting the pre-reduction furnace 4 to the analysis furnace 3, and helium in the analysis furnace 3 A gas cylinder 6 for supplying an inert gas such as (He) and an infrared gas analyzer 7 for measuring the amount of gas generated by analyzing the inert gas that has passed through the analysis furnace 3 are provided. Further, 3p is a power control unit of the analysis furnace 3.
FIG. 2 shows a more specific configuration of the contained oxygen analyzer 1. In FIG. 2, the graphite crucible 2 is a bottomed cylindrical body having a substantially U-shaped cross section, and an upper electrode constituting the analysis furnace 3. 3a and the lower electrode 3b are installed in a space A that is blocked from outside air. 3c is a power source for heating the graphite crucible 2 by passing a current controlled by the power control unit 3p between the electrodes 3a and 3b, and 3d is a sample S to be measured and a metal solvent F in the upper part of the analysis furnace 3. And 3e is a discharge part of the helium gas (He) that has passed through the graphite crucible 2.

  Reference numeral 3f denotes an internal space of the upper electrode 3a, and the graphite crucible 2 can be rapidly cooled by flowing, for example, cooling water into the internal space 3f. Further, by forming a flow path switching valve 7a between the analysis furnace 3 and the analyzer 7, it is possible to select whether the gas from the discharge unit 3e is supplied to the analyzer 7 or exhausted.

  The prereduction furnace 4 is, for example, a generally cylindrical prereduction crucible 4b arranged in a horizontal direction so as to wind a heater 4a, a power source 4c of the heater 4a, and the movement of the sample S to be measured in the crucible 4b in the horizontal direction. And a step portion 4d for holding the measurement target sample S in the crucible 4b. In addition, one end side of the analysis furnace 3 is connected to the communication path 5 and the other end side is formed with a discharge hole 4e for the helium gas (He).

  The heat source of the preliminary reduction furnace 4 is not limited to an electric furnace using the heater 4a, and various types of heat sources such as an impulse furnace and an induction heating furnace can be used. Further, the gas used for the reduction is not limited to helium (He), and other inert gas such as argon Ar may be used. In addition, other than the inert gas, a substance that easily binds to oxygen such as hydrogen may be used. In any case, the sample S to be measured is configured to be able to reduce the oxide film of the surface layer by being heated while being isolated from the atmosphere.

  Reference numeral 8 denotes a sample loading means for loading the measurement target sample S located in the prereduction furnace 4 into the graphite crucible 2, and in this example, an electromagnet 8a that adsorbs the measurement target sample S by an attractive force using magnetic force. And a power source 8b, a rod 8c made of a magnetic material for applying a smaller magnetic force to the sample S to be measured, and moving the rod 8c in the horizontal direction to move the sample S to be measured to the step 4d. And a sliding drive unit 8d that moves in the horizontal direction. That is, each part 8a-8d comprises the actuator which guides the measuring object sample S in the analysis furnace 3 by moving the measuring object sample S against the step part 4d in the horizontal direction.

Incidentally, by using an electromagnet to specimen dosing means 8, and the electrically controllable transfer of sample S to be measured using the sample loading unit 8, and, by using the rod 8c of the magnetic body, Although it is possible to act a weak magnetic force efficiently measuring object sample S, may be a permanent magnet specimen dosing means 8, without using the rod 8c, directly act on the sample S to be measured the force You may let them.

  Furthermore, when the measurement target sample S is not a magnetic body, as shown in a modified example in FIG. 4, the measurement target sample S is pushed out from the other end side of the preliminary reduction furnace 4 by the rod body 8e, so that the step 4d. It is also possible to move in the horizontal direction against this. That is, the sample S to be measured according to the present invention is not limited to a magnetic material such as steel, but may be a non-ferrous metal such as copper. In this case, the sample input means 8 may be variously modified.

  The communication passage 5 is similar to a columnar sample holder 5a for receiving the measurement target sample S introduced by the sample introduction means 8 and then introducing it into the graphite crucible 2, and tin (Sn) as the metal bath F, for example. And a cylindrical sample holder 5b for temporarily receiving it and putting it into the graphite crucible 2. Note that the detailed configuration of the sample holders 5a and 5b is as shown in Japanese Patent Laid-Open No. 2000-55794 proposed by the present inventors, and thus detailed description thereof is omitted.

  The analyzer 7 may be an NDIR (non-dispersive infrared gas analyzer), for example, as an example of a concentration analyzer that can analyze the oxygen concentration with high accuracy. If there is, it does not limit the kind. That is, a mass spectrometer may be used instead of NDIR. Furthermore, it is also possible to simultaneously analyze the contents other than oxygen contained in the measurement target sample S using a multi-component analyzer such as FTIR (Fourier transform infrared gas analyzer).

  FIG. 3 is a view for explaining a method for analyzing oxygen contained in the sample S to be measured using the oxygen analyzer 1. The upper half in FIG. 3 shows the operation in the preliminary reduction furnace 4, and the lower half shows the operation in the analysis furnace 3. In any case, the time change of the temperature in the furnace is shown in correspondence with the time change of the amount of reduced oxygen reduced thereby.

First, a sample S to be measured was put into the pre-reduction furnace 4 at time T _11, the boiling point (1540 ° C.) of iron the pre-reduction furnace 4 at a time point T ₁₂ is heated at a temperature below, for example 900-1400 ° C. Then, degassing is performed to remove the oxide film on the surface. At this time, the oxygen from the oxide film on the surface of the sample S to be measured is reduced, as shown in S _11, is converted to a gas such as carbon monoxide (CO), it is discharged from the discharge hole 4e.

The pre-reduction is carried out for example 5 minutes, by stopping the heating by the heater 4a at time T _13, cooling the sample to be measured S. In addition, since the above-described preliminary reduction is performed while supplying helium gas (He), the periphery of the sample S to be measured is surely isolated from the atmosphere by the flow of helium gas (He). In particular, even if the communication passage 5 and the inside of the prereduction furnace 4 are not completely confidential, and there is a small gap, helium gas (He) passes from the inside to the outside of the communication path 5 or the prereduction furnace 4 through this gap. As a result, the inside pressure becomes higher than the outside pressure, so that the outside air does not flow back into the inside.

The sample to be measured S (steel) is to generate a magnetic by an electromagnet 8a at T ₁₄ that drops below the Curie temperature, sliding the rod 8c by sliding the drive unit 8d. As a result, the steel S can be adsorbed by using an attractive force due to magnetic force, and can be moved to the position immediately above the communication path 5 beyond the stepped portion 4d. By stopping energization of the electromagnet 8a, the steel S can be moved to the sample holder 5a. Can be put in.

On the other hand, in the analysis furnace 3, the inside of the analysis furnace 3 is heated for example to 3000 ° C. close at time T _15, degassed of oxygen therein, analysis temperature the temperature in the analytical furnace 3 at a time point T ₁₆ (e.g. 2400 ° C). In this case carbon monoxide generated in the analytical furnace 3 (CO), as shown in the curve S _12, it decreases again once increased. Note that, after degassing, the graphite crucible 2 steadily generates gas (CO) even when the temperature is adjusted to the analysis temperature.

Next, at time T ₁₇ , tin Sn as a powder or granular metal bath F is introduced into the graphite crucible 2 using the sample holder 5 b, and accordingly, the tin Sn is dissolved and the bath F is in the bath F. When the oxygen is released, carbon monoxide (CO) is generated.

Reference sign S ₁₃ indicates the amount of carbon monoxide (CO) generated by the addition of tin Sn. By using the metal baths F, decomposition can be performed reliably thermal oxide, it is possible to prevent the capture of the generated carbon monoxide (CO) gas.

  Furthermore, when the inside of the analysis furnace 3 is stabilized at the analysis temperature, all the oxygen in the bath agent F is eventually released, and the concentration of carbon monoxide (CO) detected by the analyzer 7 is stabilized. In the graphite crucible 2, a molten tin Sn metal bath F ′ (see FIG. 2) is formed.

  Note that the degassing of the graphite crucible 2 in the analysis furnace 3 and the formation of the metal bath F ′ with tin Sn may be performed concurrently with the reduction of the oxide film of the sample S to be measured in the preliminary reduction furnace 4. Well, this can reduce the measurement time.

Next, when the concentration of carbon monoxide (CO) is stabilized, the concentration of carbon monoxide (CO) detected at this time is stored as a measurement reference value (baseline) B, and the temperature of the graphite crucible 2 is stored. the in a state of being stabilized in the analysis temperature, the sample S to be measured after the pre-reduction is charged into the graphite crucible 2 by using a sample holder 5a at time T _18. Reference sign S ₁₄ indicates the amount of carbon monoxide (CO) generated as the measurement target sample S is introduced.

Then, by integrating the measured values in the upper part (increase part) from the baseline B, the amount of oxygen contained in the measurement target sample S can be accurately obtained. Since the surface oxidation of the sample S to be measured is 0.3 μg / g and the analysis target level is about 3 μg / g, if oxygen contained in the oxide film is added to the analysis result, the influence of the measurement variation is large, resulting in it becomes R = 0.5, it is possible to measure completely remove front surface oxide film, it is possible to improve the accuracy of analysis.

Here, if the total weight of the sample S to be measured is 1 g, the weight of the oxide film is extremely thin, for example, about 150 nm. That is, for a sample having a radius of 3.15 mm, 0.000015 / 3.15 is negligible with respect to the total weight. In other words, the oxide film has a very high concentration of oxygen,
0.3 μg / (5.1 × π × 4/3 × 0.0004465 × 1000 μg)
≒ 0.3 / 9.54 ≒ 0.03,
O ₂ / Fe ₂ O ₃ = 32 / (55.8 × 2 + 16 × 3) = 0.2.
Therefore, the average concentration of Fe ₂ O ₃ contained in the 150 nm thin film is
Since 0.2 × 15% = 0.03, the analysis accuracy is improved to R = 0.1 with respect to the analysis value of 3 μg / g.

In other words, it is possible to provide a time difference between the introduction of on and the measurement object sample S of metallic baths F, it is constantly generated from the oxygen and the graphite crucible 2 is included in the metal bath F 'monoxide Heating at a constant analysis temperature until the carbon (C0) is stabilized, and when this is stabilized, the measurement target sample S can be dropped after setting it as the baseline B, so that the correction of the baseline B is ensured Can be done. This can dramatically improve the analysis accuracy. In addition, since the surface oxide film is removed only once, the measurement can be performed more quickly than in the conventional technique as shown in FIG.

5 to 7 are diagrams showing a second reference example. FIG. 5A shows the configuration of the preliminary reduction furnace 10 corresponding to the preliminary reduction furnace 4, and FIG. FIG. 7A to FIG. 7C are diagrams for explaining a method of putting the measurement target sample S into the oxygen analyzer main body 1 ′. In the example shown in FIGS. 5-7, since the part which attached | subjected the same code | symbol as FIGS. 1-4 is the same or equivalent part, the detailed description is abbreviate | omitted.

Figure 5 (A), the pre備還source furnace 10 is intended to be provided separately from the oxygen analyzer body 1 ', to heat the sample S to be measured by inserting the sample holder 11 therein The oxide film formed on the surface is reduced.

  The preliminary reduction furnace 10 includes, for example, a guide cylinder 10a in which the sample holder 11 can be inserted, a heater 10b wound around the outer periphery of the guide cylinder 10a, and a power source 10c for supplying power to the heater 10b. ing.

  On the other hand, the sample holder 11 is, for example, a preliminary reduction crucible 11a that heats the sample S to be measured, and a cylindrical body 11b that holds the preliminary reduction crucible 11a in contact with the outer periphery of the preliminary reduction crucible 11a. And an inflow port 11d of helium gas (He) as an inert gas together with a bottomed cylinder 11c rotatably attached so as to cover the cylinder 11b, and a door for sealing one end of the cylinder 11b. And a flow rate adjusting valve 11f for this helium gas (He).

  Further, on the bottom surface of the cylinder 11c, a discharge port 11g for the helium gas (He) is formed at a position off the center on the other end side of the sample holder 11, and this cylinder is formed on one end side. A flange 11h for rotating the body 11c is formed. On the other hand, on the other end side of the preliminary reducing crucible 11a, a step portion 11h is formed to protrude inside to hold the sample S to be measured at a position where the discharge port 11g is blocked. A discharge port 11j for discharging such helium gas (He) is formed.

  The bottom surface of the cylinder 11c is configured as a lid 11k that opens and closes the other end of the sample holder 11 as the cylinder 11c rotates.

  Therefore, by energizing the heater 10b while flowing the helium gas (He) while the other end of the sample holder 11 is inserted into the guide cylinder 10a, the sample holder 11 is filled with helium gas (He). The measurement target sample S can be heated while purging, and the oxide film of the measurement target sample S can be reduced while keeping the state isolated from the atmosphere.

  On the other hand, as shown in FIG. 5B, the analyzer main body 1 'forms a hopper 12 that allows the sample S to be measured in the sample holder 11 to be charged while keeping the state isolated from the atmosphere.

  The configuration of the hopper 12 includes, for example, an opening 12a that can communicate with the analysis furnace 3 and maintain an isolated state from the atmosphere by flowing helium gas (He) as an example of an inert gas therein. A lid 12b for opening and closing the open end of the opening 12a, a hook 12c for holding the lid 12b in a closed state, and an opening 12a for keeping the opening 12a airtight from the outside with the lid 12b closed. It has a seal 12d (O-ring).

  Accordingly, both the metal bath agent F and the sample S to be measured can be supplied through the same opening 12a, and the opening 12a is purged with helium gas (He) and isolated from the atmosphere. It is possible to keep it in a state. Moreover, since the consumption of helium gas (He) can be suppressed by closing the lid 12b, the running cost can be suppressed.

Since none of the metallic bath agent F and the measurement object sample S is configured to be turned through the same opening 12a, are illustrated sample holder 5a when to hold the metal bath agent F to the sample holder 5b It is desirable to open the communication path 5 by sliding in such a manner. Similarly, when the sample S to be measured held by the sample holder 5a is put into the graphite crucible 2, the sample holder 5b is slid as shown in FIG. It is desirable to do. Furthermore, the deformation | transformation which forms the sample holder which put together the sample holder 5a and the sample holder 5b is also considered.

FIG. 6 shows a modification of the hopper 12 shown in FIG. 5B, and 12e is a lid that slides in the horizontal direction with respect to the opening 12a. With this configuration, the volume of the opening 12a can be reduced. In other words, the lid body may be configured to rotate so as to hold the opening 12a from above and close it, or to open and close by sliding left and right. By sliding in the left-right direction, the volume of the opening 12a can be reduced, and the consumption of the inert gas (He) consumed in accordance with the opening / closing operation of the lid 12e can be further reduced.

  Next, the operation when the sample S to be measured after performing the preliminary reduction in the preliminary reduction furnace 10 using the hopper 12 is introduced through the opening 12a will be described. 7 shows an example of the hopper 12 in which the lid body 12b that is opened / closed mainly by turning in the vertical direction is shown. However, the hopper 12 in which the lid body 12e that is opened / closed by sliding is formed is also used. The sample S to be measured can be input by the same method.

  First, as shown in FIG. 7A, the lid 12b is opened to allow the sample holder 11 to be inserted. At this time, helium gas (He) continues to flow out from both the opening 12a and the discharge port 11g, and the sample S to be measured is kept isolated from the atmosphere in the sample holder 11. Then, by tilting the sample holder 11 slightly, the sample S to be measured is moved to a position away from the stepped portion 11i. In order to facilitate the insertion of the sample holder 11, it is desirable that its outer diameter is formed somewhat smaller than the inner diameter of the opening 12a.

  Next, as shown in FIG. 7B, the sample holder 11 is inserted into the opening 12a. At this time, helium gas (He) supplied to both the sample holder 11 and the hopper 12 is discharged to the outside through a gap formed between the inner periphery of the opening 12 a and the outer periphery of the sample holder 11. Therefore, the flow is fast, and the air does not flow back into this. That is, the space A ′ in the opening 12a is reliably isolated from the atmosphere. Note that if the outer diameter of the sample holder 11 is made too small compared to the inner diameter of the opening 12a, the gap becomes wider, so that helium gas (He) is discharged at a sufficient flow rate so that the atmosphere does not enter. It is necessary to let

  Then, as shown in FIG. 7C, by rotating the flange 11h from one end side of the sample holder 11, the position of the discharge port 11g is adjusted to the position of the sample S to be measured. The body 11k is opened, and the measurement target sample S can be transferred to the sample holder 5a in a state where it is isolated from the atmosphere. That is, even when the measurement target sample S is transferred using the sample holder 11, the state completely isolated from the atmosphere by the flow of the inert gas (He) can be maintained.

With such a configuration, the same effects can be obtained in the case shown in FIGS. 1-4, by forming a pre-reduction furnace 10 as dare separate, the contained oxygen analyzing apparatus 1 main body 1 'of the The configuration can be simplified. Moreover, it becomes feasible only by attaching the hopper 12 to the existing oxygen analyzer 1. The measurement procedure is the same as in the first reference example.

8 and 9 are views showing a third reference example, FIG. 8 (A) ~ FIG 8 (C) is a diagram showing the structure and operation including aerobic analyzer 1, 9 this analysis It is a figure which shows the relationship between the temperature in the furnace 3, and the amount of generated gas (signal amount of the analyzer 7). In FIGS. 8 and 9, the same reference numerals as those in FIGS. 1 to 7 are the same or equivalent parts, and detailed description thereof is omitted.

  In this example, the position of the sample holder 5a that holds the sample S to be measured and puts it into the graphite crucible 2 and the position of the sample holder 5b that holds the metal bath F and puts it into the graphite crucible 2 are shown in FIG. They are arranged so as to be opposite to those shown in 2 and 4.

  In the oxygen analyzer 1 of this example, a magnet 13 is disposed on the side surface of the graphite crucible 2, and this magnet 13 is controlled by a control unit (not shown) of the oxygen analyzer 1 as shown in FIGS. It is possible to move to at least three positions shown in (C). The sample S to be measured by the oxygen analyzer 1 in this example is a magnetic material (preferably a ferromagnetic material) such as steel, and the metal bath F is a non-magnetic material (a material that is not a ferromagnetic material). That is, the magnet 13 is an example of a sample taking-out means for temporarily taking out and holding the measurement target sample S in the graphite crucible 2 while being isolated from the atmosphere.

As shown in FIG. 9, in the oxygen analyzer 1 of the present example, first, the graphite crucible 2 is heated to about 3000 ° C. and degassed between time points T _{31 and} T _32. Wait until the temperature in 3 drops below the boiling point of iron at 1540 ° C. At time T ₃₃ , the steel S is put into the graphite crucible 2 and the temperature in the analysis furnace 3 is adjusted to 900 ° C. to 1400 ° C. to reduce the oxide film on the surface of the steel S.

Then, when reduction of the oxidized film of the steel S is completed, stop the heating of the analytical furnace 3 at a time point T _34, the temperature of the steel S waits for the cooling to the Curie temperature (780 ° C.) or less. At time T ₃₅ , the magnet 13 is disposed at the position shown in FIG. 8A to attract the steel S by a magnetic force, and the magnet 13 is moved upward as shown in FIG. 8B. The steel S is moved from the outside of the analytical furnace 3 to a place where the heat of the carbon furnace 2 does not reach. That is, the magnet 13 of this example constitutes a magnetic force guiding portion that enables the steel S to be taken out from the graphite crucible 2 using an attractive force due to magnetic force.

After moving the steel S, at time T _36, heating temperature in the analytical furnace 3 analysis temperature (2400 ° C.), at time T _37, sliding the sample holder 5a as shown in FIG. 8 (B) Then, the communication path 5 is opened, the sample holder 5b is rotated, and the powder or granular metal bath F is put into the graphite crucible 2. As a result, the bath agent F forms a metal bath F ′ and releases oxygen therein, and stores this as the baseline B when the amount of gas generated from the graphite crucible 2 is stabilized.

At time T ₃₈ , as shown in FIG. 8 (C), the steel 13 can be released from the influence of the magnetic force by pulling the magnet 13 away from the analytical furnace 3, and this can be put into the graphite crucible 2. can, it is possible to accurately measure the oxygen content inside the steel S from the signal S _14.

  By configuring as in this example, the oxide film formed on the surface of the sample S to be measured in one graphite crucible 2 can be completely removed, and the metal bath F is heated and dissolved in the same graphite crucible 2. Then, the degassing is performed, and the sample S to be measured is heated again in a state where the baseline B is stable, and this is dissolved, so that the amount of oxygen contained therein can be analyzed with high accuracy. That is, the configuration of the oxygen analyzer 1 is very simple, but it is possible to perform highly accurate analysis using the metal bath F, and the manufacturing cost can be reduced.

  And since the measuring object sample S after reducing the oxide film can be analyzed without being taken out from the contained oxygen analyzer 1, the state cut off from the atmosphere can be reliably maintained, and the oxide film can be re-formed. Can be reliably prevented. In addition, unlike the conventional example shown in FIG. 14, it is not necessary to repeat the process of removing the oxide film of the sample S to be measured many times, so that the analysis can be performed quickly.

  In the above example, an example in which a permanent magnet is used as the magnet 13 is shown. However, instead of this, an electromagnet can be used. In this case, the strength of the magnetic force applied to the measurement target sample S is increased. Since it is electrically adjustable, the movement of the magnet can be reduced. Further, as in the example shown in FIG. 2, it is possible to effectively apply a weaker magnetic force by using the rod 8c.

  In addition, when the sample S to be measured is not a magnetic body, a sample taking-out means that performs scooping using suction or a rod may be formed.

10 and 11 are views showing an embodiment of the present invention is a modification of the contained oxygen analyzing apparatus of the third reference example shown in FIGS. 8 and 9. 10 (A) to 10 (E) are diagrams showing the configuration and operation of the oxygen analyzer 1 in this example, and FIGS. 11 (A) to 11 (C) show the temperature in the analysis furnace 3 and the operation. It is a figure which shows the relationship of the gas amount (signal amount of the analyzer 7) to generate | occur | produce. FIG. 11A shows the temperature change of the graphite crucible 2, and FIGS. 11B and 11C show the amount of oxygen that is reduced by heating.

  10 and 11, the same reference numerals as those in FIGS. 1 to 9 are the same or equivalent, and thus detailed description thereof is omitted. In addition, the measurement target sample S in this example is also a magnetic body, for example, steel. On the other hand, the metal bath agent F is a non-magnetic material, for example, tin.

  In FIG. 10, reference numeral 14 denotes a rod body as an example of a sample take-out means for temporarily taking out and holding the measurement target sample S in a state isolated from the atmosphere, and reference numeral 15 denotes a permanent member attached to the distal end portion 14 a of the rod body 14. A magnetic force acting portion formed by a magnet (ferromagnetic material), 16 is a lid formed so as to be able to seal the communication path 5, and 17 is an actuator for sliding the rod 14 in the vertical direction. Further, the rod body 14 penetrates the lid body 16 so as to be movable back and forth (up and down) and to be airtight with respect to the outside air.

  In addition, although illustration is abbreviate | omitted also in the oxygen analyzer 1 of this example, the said flow-path switching valve 7a (refer FIG. 2) is formed between the analysis furnace 3 and the analyzer 7. FIG. That is, by switching the flow path switching valve, it is possible to control so that the generated oxidizing gas does not flow to the analyzer 7 in the preliminary reduction of the sample to be measured and the degassing of the graphite crucible 2.

Next, describing the operation of the contained oxygen analyzing apparatus 1 of the present embodiment, first, as shown in FIG. 11 (A), first, in the period from the time point T ₄₁ through T _42, in the state shown in FIG. 10 (A), The graphite crucible 2 is heated to about 2900 ° C. At this time, in FIG. 11 (B), as indicated by reference numeral S _12, the graphite crucible 2 is degassed. However, the gas flow path of carbon monoxide (CO) generated by the reduction at this time is switched so as not to flow to the analyzer 7 by the flow path switching valve 7a or the like. Thereafter, the temperature is adjusted to about 1000 ° C., for example.

Next, at time T ₄₃ , as shown in FIG. 10B, when the sample holder 5 a is slid to put the steel S into the graphite crucible 2, the oxidation on the surface of the steel S is performed as shown by reference numeral S _11. The membrane is reduced and a gas such as carbon monoxide (CO) is discharged. Then, the heating of the graphite crucible 2 is stopped at the time T ₄₄ that sufficient time has passed, the temperature inside the graphite crucible 2 is cooled to about room temperature 25 ° C..

The graphite crucible 2 can be quickly cooled by flowing cooling water into the internal space 3f of the upper electrode 3a shown in FIG. Then, an analysis furnace 3 and the analyzer 7 switches the gas passage so as to communicate at time T _45.

Further, at time T ₄₆ , the sample holder 5 b is slid to put the metal bath F into the graphite crucible 2, and the rod body 14 is suspended in the graphite crucible 2 using the actuator 17. At this time, the temperature of the steel S is cooled to the Curie temperature (780 ° C.) or less, and both the metal bath F and the steel S are contained in the graphite crucible 2, but the tip 14 a of the rod 14 is in the tip 14 a. Only the magnetic steel S is attracted by the magnetic force of the attached permanent magnet 15.

  Therefore, as shown in FIG. 10 (D), when the actuator 17 pulls up the rod body 14, only the steel S can be adsorbed to the tip end portion 14a, and only this steel S can be taken out from the graphite crucible 2. Further, the magnetic force of the permanent magnet 15 is sufficient to selectively attract and lift the steel S in the graphite crucible 2, and there is no need to inadvertently generate strong magnetism, and there is almost no influence on the surroundings. It can be.

  In addition, in this example, the configuration is simplified by using a ferromagnetic permanent magnet as the magnetic force acting portion 15, but the magnetic force acting portion 15 formed at the distal end portion 14 a of the rod body 14 is a permanent magnet. It is not limited, and may be formed by an electromagnet attached to the base end portion of the magnetic rod 14. In this case, the magnitude of the attractive force acting on the steel S can be adjusted by the magnitude of the electric power supplied to the electromagnet.

When the steel S is pulled up from the graphite crucible 2, the graphite crucible 2 is heated again at the next time T ₄₇ , and the temperature is adjusted to 2200 ° C. to 2400 ° C. At this time, the metal bath F is dissolved, oxygen contained therein is reduced, and the oxidizing gas as shown in the curve S ₁₃ is detected by the detector 7. And if the metal bath agent F melt | dissolves and it becomes metal bath F 'and the oxygen contained in this is reduce | restored, the density | concentration of oxidizing gas will be stabilized.

If the concentration of the oxidizing gas to be detected by the detector 7 is stabilized, then you perform setting of the reference value B during the time T ₄₈ ~ time T _49. At time T ₅₀ , the steel S is again put into the graphite crucible 2 as shown in FIG. At this time, the actuator 17 further pulls up the rod body 14, thereby further pulling the rod body 14 into a through hole 16 a (see FIG. 10) for the rod body 14 formed in the lid body 16. The steel S is put into the graphite crucible 2 so that the force acting on the steel S becomes smaller than gravity.

  However, when the magnetic force acting part 15 is formed of an electromagnet, the steel S can be put into the graphite crucible 2 by stopping the power supplied to the electromagnet.

  By configuring as in this example, it is not necessary to intensify the magnetic force generated from the magnetic force acting portion 15 formed at the tip end portion 14a of the rod body 14, and the steel S can be reliably adsorbed. The configuration of the extraction means can be simplified as much as possible. That is, the manufacturing cost can be reduced accordingly, energy saving, and there is no possibility of affecting the operation of surrounding devices. In addition, since the operation of taking out the steel from the graphite crucible by adsorption by magnetic force is sufficient only for the vertical sliding of the rod, automation can be easily achieved.

FIG. 12 is a diagram showing a fourth reference example . The oxygen analyzer 1 shown in FIG. 12 is a further modification of the sample extracting means 13 and 14 shown in FIGS. 8 and 10, and the same reference numerals as those in FIGS. 1 to 11 denote the same or equivalent members. Therefore, detailed description thereof is omitted.

  In FIG. 12, reference numeral 18 has a forceps 18a for gripping the sample S to be measured at the distal end, and tilting in the two-dimensional directions X and Y of the forceps 18a and a gripping operation (arrow C direction) of the forceps 18a at the proximal end. A gripping means 19 having an operation portion 18b to be performed, a fiberscope 19 for being arranged along the gripping means 18 and confirming the state in the vicinity of the tip portion by an image V, and 20 being transmitted by a pixel fiber 19a of the fiberscope 19 The display unit 21 for displaying the image V is a light source for irradiating light into the graphite crucible 2 using the projecting optical fiber 19 b of the fiber scope 19. That is, the sample take-out means 22 in this example includes the gripping means 18, the fiber scope 19, the display unit 20, and the light source 21.

Containing aerobic analyzer 1 Ho Isuzu performs analyzed as actual施例shown in FIGS. 10 and 11. Then, in taking out the measurement target sample S at time T ₄₆ in FIG. 11, the gripping means is suspended in the graphite crucible 2 as indicated by an arrow D. At this time, the operator can check the situation in the vicinity of the tip of the gripping means 18 in real time using the image V displayed on the display unit 20 and can operate the operation unit 18b while viewing the image V.

That is, since the operator can operate the operation unit 18b while looking at the display unit 20 and grasp the measurement target sample S with the forceps 18a, no matter what the material of the measurement target sample S is, This can be securely grasped and taken out from the graphite crucible 2 as shown by an arrow E. Also, introduction of the measurement object sample S at time T ₅₀ can be easily performed by operating the operation portion 18b.

Incidentally, the containing aerobic analyzer 1 gripping means 18 described above, the fiber scope 19, a display unit 20, and are not intended to limit the detailed configuration of the light source 21. Further, in this example, an example is shown in which the operator manually operates, but each operation indicated by the arrows C to E, X, and Y can be controlled by electrically controlling the operation unit 8b and the like. It may be possible by electrical control from the main body side.

In each example described above, an example in which the metal bath agent F is used to heat and dissolve the measurement target sample S is shown, so that even when the oxygen concentration of the measurement target sample S is high, the heat-resistant oxide is decomposed. it is possible to reliably perform. Moreover, although the example which uses helium gas (He) is shown as an example of inert gas, it can replace with this helium gas (He) and can use argon gas (Ar) and other inert gas. Needless to say.

It is a figure which shows roughly the structure of the principal part of the oxygen content analyzer of a 1st reference example. It is a figure which shows the structure of the said oxygen analyzer. It is a figure for demonstrating operation | movement of the said oxygen analyzer. It is a figure which shows the modification of the said oxygen analyzer. It is a figure which shows the structure of the oxygen analyzer of a 2nd reference example. It is a figure which shows the modification of the said oxygen analyzer. It is a figure for demonstrating operation | movement of the said oxygen analyzer. It is a figure explaining the structure and operation | movement of a contained oxygen analyzer of the 3rd reference example . It is a figure for demonstrating operation | movement of the oxygen analyzer of a 3rd reference example . FIG. 9 shows an embodiment of the present invention and is a diagram showing a modification of the oxygen analyzer shown in FIG. 8. It is a diagram for explaining the operation of the contained oxygen analyzer before you施例. The fourth reference example is shown to view. It is a figure explaining an example of operation | movement of the conventional oxygen analyzer. It is a figure explaining another example of operation | movement of the conventional oxygen analyzer.

Explanation of symbols

1 containing oxygen analyzer equipment 2 graphite crucible 3 Analysis furnace 13 sample extraction means (magnetic induction unit)
14 Sample removal means (rod)
18 Grasping means 19 Fiberscope 20 Display unit 22 Sample taking means (two-dimensional fiberscope)
B Reference value F Metal bath agent S Sample to be measured

Claims (5)

A graphite crucible installed in a space cut off from the outside air is provided in the analysis furnace, and a sample holder for introducing a metal bath agent into the graphite crucible and a sample holder for introducing a sample to be measured are respectively provided. Installed above the analysis furnace,
Preliminarily reduce the oxide film on the surface by heating the sample to be measured put in from the sample holder to a temperature below the melting point in the graphite crucible,
Temporarily by the sample extraction means in a condition in which the the pre-reduced measured sample, wherein the sample holder or we throw input metal baths coexist in a graphite crucible, the only constant target sample measured was isolated from the atmosphere The metal bath remaining in the graphite crucible is heated and dissolved, and then the sample to be measured held by the sample take-out means is put into the graphite crucible while being isolated from the atmosphere. A dissolved oxygen analyzer for analyzing the oxygen content of the sample to be measured,
The sample take-out means is composed of a rod body that slides in the vertical direction so as to be airtight against the outside air, and the rod body has a lower tip for taking out and holding the sample to be measured, while the rod An oxygen analyzer comprising an actuator for sliding a body in a vertical direction. 2. The oxygen analyzer according to claim 1, wherein the sample to be measured is steel, and the rod body has a magnetic force induction portion at a lower end portion thereof that allows the steel to be taken out from the graphite crucible by magnetic attraction. 2. The oxygen content analysis according to claim 1, wherein the sample to be measured is steel, and the rod body has a magnetic force acting part that allows the steel in the graphite crucible to be taken out from the graphite crucible by adsorption by magnetic force at a lower end portion thereof. apparatus. A communication path that communicates with the metal bath agent and the sample to be measured is provided above the sample holder, a cover body that can be sealed is provided, and the actuator is provided above the cover body. The rod according to any one of claims 1 to 3, wherein the rod is attached to the actuator in a state of penetrating so as to be movable up and down with respect to the lid and airtight with respect to outside air. Oxygen analyzer. A graphite crucible installed in a space cut off from the outside air is provided in the analysis furnace, and a sample holder for introducing a metal bath agent into the graphite crucible and a sample holder for introducing a sample to be measured are respectively provided. Installed above the analysis furnace,
Preliminarily reduce the oxide film on the surface by heating the sample to be measured put in from the sample holder to a temperature below the melting point in the graphite crucible,
Temporarily by the sample extraction means in a condition in which the the pre-reduced measured sample, wherein the sample holder or we throw input metal baths coexist in a graphite crucible, the only constant target sample measured was isolated from the atmosphere The graphite crucible in which the metal bath is left is heated above its melting point and below its boiling point, and the oxygen contained therein is reduced by dissolving the metal bath,
In a state where the amount of gas generated from the heated graphite crucible is stable, this amount of gas is obtained as a reference value, and while maintaining the temperature of the graphite crucible at this time, the sample to be measured held by the sample take-out means is obtained. When performing a series of analysis operations in which the oxygen content of the sample to be measured is analyzed from the amount of gas generated by heating by melting it in a graphite crucible while being isolated from the atmosphere,
Contained in that the sample taking-out means is a rod body that slides up and down by an actuator so as to be airtight against the outside air, and has a lower tip for taking out and holding the sample to be measured. Oxygen analysis method.

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