JP5329037B2 - Oxygen pump - Google Patents

Description

The present invention relates to an oxygen pump.

  Conventionally, a method for producing a single crystal sample or the like using an atmospheric gas whose oxygen partial pressure is controlled by an oxygen partial pressure control device having an electrochemical oxygen pump containing a solid electrolyte is known (Patent Document). 1).

  The oxygen partial pressure control apparatus shown in FIG. 3 includes a mass flow controller (MFC) 3 that controls the flow rate of the inert gas that has passed through the valve 2 to a set value, and the inert gas that has passed through the mass flow controller 3 as a target oxygen component. The oxygen oxygen for supply gas supplied to the next process (apparatus) such as a sample growing apparatus by monitoring the oxygen partial pressure of the inert gas controlled by the oxygen pump 4 and the inert gas controlled by the oxygen pump 4 It has a sensor 5.

Further, this apparatus compares the monitored value by the oxygen sensor 5 with the set value by the oxygen partial pressure setting unit 6 and the inertness sent out from the oxygen pump 4 to set a desired oxygen partial pressure value. An oxygen partial pressure control unit 7 that controls the oxygen partial pressure of the gas to a predetermined value and an oxygen partial pressure display unit 8 that displays a monitor value by the oxygen sensor 5 are provided. Normally, the oxygen partial pressure in the inert gas is about 10 ⁻⁴ atm.

As shown in FIG. 4, the electrochemical oxygen pump 4 has electrodes 4b and 4c made of platinum formed on both inner and outer surfaces of a solid electrolyte cylindrical body 4a having oxygen ion conductivity. The solid electrolyte cylindrical body 4a is, for example, a zirconia solid electrolyte, and is heated to about 600 ° C. by a heater (not shown). An inert gas is supplied in the axial direction from one opening of the solid electrolyte cylindrical body 4a toward the other opening. The inert gas is, for example, Ar + O ₂ (10 ⁻⁴ atm). A DC voltage of a DC power source E is applied between the inner and outer electrodes 4b and 4c. When a positive electrode is applied to the outer electrode 4c and a negative electrode is applied to the inner electrode 4b to flow a current I, oxygen molecules (O ₂ ) in the inert gas flowing through the solid electrolyte cylindrical body 4a are electrically charged. It is reduced to ions (O ²⁻ ) and released again as oxygen molecules (O ₂ ) through the solid electrolyte to the outside of the solid electrolyte cylindrical body 4a. Oxygen molecules released to the outside of the solid electrolyte cylindrical body 4a are exhausted together with an auxiliary gas such as air. The inert gas of Ar + O ₂ (10 ⁻⁴ atm) supplied to the solid electrolyte cylindrical body 4a becomes a processed gas (purified gas) that is controlled to a target oxygen partial pressure by reducing oxygen molecules, and is the next step. (Device).

In addition, the oxygen pump 4 of FIG. 4 can also perform a pump operation by applying a DC voltage having the opposite polarity between the electrodes 4b and 4c on the inner and outer surfaces of the solid electrolyte cylindrical body 4a. That is, when a negative electrode is applied to the outer electrode 4c and a positive electrode is applied to the inner electrode 4b, oxygen molecules (O ₂ ) in a gas such as air flowing along the outer surface of the solid electrolyte cylindrical body 4a are electrically It is reduced to ions (O ²⁻ ) and released again as oxygen molecules (O ₂ ) through the solid electrolyte into the solid electrolyte cylindrical body 4a. In this case, the oxygen partial pressure of the inert gas flowing inside the solid electrolyte cylindrical body 4a is increased and fed to the outside.

If a gas whose oxygen partial pressure is controlled by such an oxygen pump is supplied, crystal growth, alloying, heat treatment, semiconductor manufacturing process, etc. can be performed in an atmosphere such as an inert gas whose oxygen partial pressure is controlled.
JP 2002-326887 A

  In the oxygen pump shown in FIG. 4, one circular pipe-shaped solid electrolyte cylindrical body is used. That is, the gas to be treated is caused to flow in the axial direction in the internal space of the single solid electrolyte cylindrical body, and the ionic conductivity is pumped inside and outside the solid electrolyte partition wall while flowing through the solid electrolyte cylindrical body.

  However, in the case of using a solid electrolyte cylindrical body, the gas flow rate that can be processed by the gas pump is proportional to the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body. Therefore, in order to increase the gas flow rate (in order to increase the processing capacity), it is necessary to increase the contact area between the gas to be processed and the outer surface of the solid electrolyte cylindrical body.

  In order to increase the contact area, it is conceivable to lengthen the solid electrolyte cylindrical body or increase the pipe diameter. In order to effectively use the oxygen ion conductive solid electrolyte, it is necessary to reduce the resistance value of the oxygen pump as low as possible and increase the oxygen permeation capability of the oxygen pump. The resistance value of the oxygen pump is affected by the shape (surface area and thickness) of the solid electrolyte, the electrode film, the lead terminal, and the like. Among these, the shape of the solid electrolyte has a large surface area, and the resistance value decreases as the thickness decreases. That is, when considering a cylindrical body, a shape having a large diameter and length and a small thickness is preferable. However, in view of the ease of manufacturing the solid electrolyte cylindrical body and the strength of the solid electrolyte cylindrical body used in a heated and high temperature holding state, there are limits to the diameter, length, and thickness. In addition, as the pipe diameter increases, the ion conduction reaction of the gas to be processed flowing through the center of the solid electrolyte cylindrical body decreases rapidly, and as a result, the gas to be processed flowing through the center passes through without reaction. In addition, control accuracy such as oxygen partial pressure decreases. For this reason, there is a limit to simply increasing the pipe diameter of the solid electrolyte cylindrical body. Therefore, there is a limit in increasing the contact area between the gas to be treated and the solid electrolyte cylindrical body by the above method. For this reason, the gas flow rate that can be processed substantially effectively by the gas pump is limited, and the application of supplying gas with controlled oxygen partial pressure is limited.

  In view of the above problems, the present invention provides an oxygen pump that exhibits stable purification power and can increase the purification treatment capacity.

The oxygen pump of the present invention includes a solid electrolyte cylindrical body having oxygen ion conductivity, electrodes disposed on the inner surface and the outer surface of the solid electrolyte cylindrical body, and heating means for heating the solid electrolyte cylindrical body. In an oxygen pump, a plurality of solid electrolyte cylinders arranged vertically in the vertical direction are arranged in parallel at a predetermined pitch on one vertical plane through a flow rate control mechanism that makes the gas flow rate the same. The heating means is composed of a pair of planar heaters, and a plurality of solid electrolyte cylindrical bodies disposed on one vertical plane are sandwiched between the pair of planar heaters. And the flow control mechanism includes a gas branch pipe to which a gas inflow pipe is connected, a plurality of branch paths for independently supplying gas from the gas branch pipe to each solid electrolyte cylindrical body, and a gas outflow pipe Gas merging pipes connected to the A plurality of combined flow paths for supplying gas from the gas cylinder to the gas merging pipe independently, and an upstream flow path from the gas inflow pipe to the solid electrolyte cylindrical body, and gas outflow from the solid electrolyte cylindrical body Each solid electrolyte cylinder with a different total length of the upstream flow path and the downstream flow path for each solid electrolyte cylindrical body in the downstream flow path to the service pipe Gas is allowed to flow into the shape from below .

  According to the oxygen pump of the present invention, since a plurality of solid electrolyte cylindrical bodies are arranged in parallel at a predetermined pitch, it is possible to improve the gas processing capacity. In addition, since the gas flow rate of each solid electrolyte cylindrical body is the same in the flow rate control mechanism, the gas processing capacity of each solid electrolyte cylindrical body is the same.

  The upstream side flow path from the gas inflow tube to the solid electrolyte cylindrical body and the downstream side flow path from the solid electrolyte cylindrical body to the gas outflow pipe have different channel lengths, and the solid electrolyte cylindrical shape By making the total length of the upstream channel and the downstream channel for each body constant, it is possible to improve the accuracy of identifying the gas flow rate of each solid electrolyte cylindrical body.

  By the way, if the solid electrolyte cylindrical body is allowed to expand and contract in the axial direction, a part of the solid electrolyte or a part of the electrode may be peeled off due to thermal expansion or the like. Therefore, if the gas flows into the solid electrolyte cylindrical body from below, the treated gas will flow out from above, so that the peeled off solid electrolyte etc. stays below and the treated gas supply Do not let out.

  In the present invention, the gas processing capacity can be improved, and the gas processing capacity of each solid electrolyte cylindrical body is the same. For this reason, a large amount of high-quality purified gas controlled to the target oxygen partial pressure can be purified at a time. Further, by providing the flow rate control mechanism, it is possible to improve the accuracy of making the gas flow rate of each solid electrolyte cylindrical body the same.

  The solid electrolyte cylindrical body can be sandwiched by a flat heater, and a compact oxygen pump can be configured. In particular, when sandwiched between sandwiches, if a plurality of solid electrolyte cylinders are arranged at a predetermined pitch on one vertical plane, the size can be further reduced, and the oxygen partial pressure using this oxygen pump can be increased. Incorporation into the control device is improved. In addition, since a plurality of solid electrolyte cylindrical bodies are provided, the purification capacity can be improved.

  By supplying gas to the solid electrolyte cylindrical body from below, the peeled material stays below and does not flow out to the treated gas supply side. For this reason, pure purified gas can be supplied, and operations in the sample preparation chamber or the like on the gas supply side are stabilized.

  Hereinafter, an embodiment of the present invention will be described with reference to FIGS. The oxygen pump according to the present invention includes a solid electrolyte cylindrical body 30 having oxygen ion conductivity, electrodes (not shown) disposed on the inner and outer surfaces of the solid electrolyte cylindrical body 30, and the solid electrolyte cylindrical body 30. The heating means 31 which heats is provided. In this case, platinum plating etc. are given to the inner surface and outer surface of the solid electrolyte cylindrical body 30, and an electrode is comprised. This oxygen pump has a plurality (five in the illustrated example) of solid electrolyte cylinders 30, and each solid electrolyte cylinder 30 is surrounded by a heat insulating structure 35. Each solid electrolyte cylindrical body 30 and the heat insulating structure 35 are accommodated in a casing (not shown).

  The heat insulating structure 35 includes halves 37 and 37 made of a heat insulating material, and a gap 40 having a predetermined size is formed between the mating surfaces 37 a and 37 a of the halves 37 and 37. That is, the gap 40 is set to be slightly larger than the outer diameter dimension of the solid electrolyte cylindrical body 30, and the solid electrolyte cylindrical body 30 is disposed in the gap 40 so as not to contact the halved body 37.

  Here, the heat insulating material is a material that blocks the transfer of thermal energy, and includes an inorganic material and an organic material. In general, an inorganic material is used when the temperature is high, and an organic material is used when the temperature is low. Examples of inorganic heat insulating materials include fiber heat insulating materials using ceramic fibers, glass fibers, asbestos, etc., powder heat insulating materials using calcium silicate, magnesium carbonate, etc., and porous heat insulating materials such as perlite / foam glass. For this reason, since the solid electrolyte cylindrical body 30 is heated by the heating means 31 to about 600 degreeC, it can select from what can respond to this temperature.

  Moreover, rectangular recesses 41 and 41 are provided in the mating surfaces 37a and 37a, and a pair of heaters 43 and 43 constituting the heating means 31 are arranged in a space 42 formed by the recesses 41 and 41. Has been. A cover material 39 is attached to the recesses 41 and 41. As described above, this oxygen pump has a plurality of solid electrolyte cylindrical bodies 30 arranged at a predetermined pitch on one vertical plane, and a plurality of solid electrolytes by the planar heaters 43 and 43 constituting the heating means 31. A cylindrical body group 29 composed of the electrolyte cylindrical body 30 is sandwiched.

  Each heater 43 is provided with a temperature detector (not shown) (for example, a thermoelectric thermometer), and the temperature of the heater 43 is monitored. Here, the thermoelectric thermometer is a thermometer using a thermocouple. That is, the temperature measuring contact is connected to the heater side (the heater itself or a support body (not shown) supporting the heater), and the electromotive force between the temperature measuring contact and the reference contact is measured.

  Each solid electrolyte cylindrical body 30 has an upper end side and a lower end side attached to a casing (not shown) via a joint channel 55 and a branching portion 56. That is, the casing is provided with space portions at the upper and lower portions thereof, and connecting pipe joints 59 and 60 are respectively attached to the upper and lower ends of the solid electrolyte cylindrical body 30 protruding into the space portion. A gas junction pipe 61 is arranged in the upper space part, and a gas branch pipe 62 is arranged in the lower space part. Then, a connecting pipe joint 59 is connected to the gas junction pipe 61 via the joining flow path 55, and a connecting pipe joint 60 is connected to the gas branch pipe 62 via the branch portion 56.

  The combined flow path 55 and the branch path 56 are flexible pipes, and include main bodies 55a and 56a made of bellows pipes, connecting portions 55b and 56b connected to the coupling pipe joints 59 and 60, and a gas junction pipe 61 or a gas branch pipe. And connecting portions 55 c and 56 c connected to 62. As shown in FIG. 2, the main bodies 55a and 56a are formed in a loop shape.

  Each of the gas junction pipe 61 and the gas branch pipe 62 has an axial hole 66 extending in the longitudinal direction and a plurality of (in this case, five corresponding to the solid electrolyte cylindrical body 30) communicating with the axial hole 66. ) Connecting portion 67. The connecting portions 67 are arranged at a predetermined pitch (constant pitch) along the axial hole 66. Then, the junction channel 55 is connected to each connecting portion 67 of the gas junction pipe 61, and the branch path 56 is connected to each connecting portion 67 of the gas branch pipe 62.

  The gas junction pipe 61 is fixed to the upper wall of the casing, and a gas outflow pipe 68 communicated with the axial hole 66 is connected. In this case, the axial hole 66 of the junction pipe 61 opens on one side wall side (right side in FIG. 1) of the casing, and this opening is connected to the gas outflow pipe 68 fixed to one side wall of the casing. The

  The gas branch pipe 62 is fixed to the lower wall of the casing 34 and is connected to a gas inflow pipe 69 communicated with the axial hole 66. In this case, the axial hole 66 of the branch pipe 62 opens on the other side wall side (left side in FIG. 1) of the casing, and this opening is connected to the gas inflow pipe 69 fixed to one side wall of the casing. The For this reason, the gas inflow pipe 69 protrudes from the branch pipe 62 toward the other side wall, and then makes a U-turn toward the one side wall.

  In this case, gas flows into the solid electrolyte cylindrical body 30 from below through the branch pipe 62 and the branch path 56 from the lower connecting pipe 69, and oxygen molecules are reduced to control the target oxygen partial pressure. As a result, the treated gas flows out from above the solid electrolyte cylindrical body 30 to the upper connecting pipe 68 through the joining channel 55 and the joining pipe 61.

  By the way, in the oxygen pump of the present invention, the gas flowing into the solid electrolyte cylindrical body 30A on one side wall side enters the branch pipe 62 from the opening on the other side wall side, and the axial hole 66 of this branch pipe 62 Will flow into one side wall and then flow in. Then, the purified gas that has flowed through the solid electrolyte cylindrical body 30A flows into the opening side of the axial center hole 66 of the merging pipe 61 through the merging channel 55, and passes through the gas outlet pipe 68 to the oxygen sensor. To the side. The gas flowing into the solid electrolyte cylindrical body 30E on the other side wall side enters the branch pipe 62 from the opening on the other side wall side, and passes through the branch path 56 from the rolling portion 67 on the other side wall side. The gas that has flowed in and purified by the solid electrolyte cylindrical body 30E flows into the connecting portion 67 on the other side wall side of the axial hole 66 of the merging pipe 61, and flows through the axial hole 66 to the opening side. It flows out to the oxygen sensor side through the outflow pipe 69.

  That is, in this oxygen pump, a branch path 56 for supplying gas from the gas branch pipe 62 to each solid electrolyte cylindrical body 30, a gas branch pipe 62 to which a gas inflow pipe 69 is connected, and a gas outflow pipe 68 are provided. A flow rate control mechanism M including a connected gas merging pipe 61, a merging channel 55 that supplies the gas merging pipe 61 from each solid electrolyte cylindrical body 30, a gas inflow pipe 69, and a gas outflow pipe 68 Composed. By this flow rate control mechanism M, in the upstream flow path 76 from the gas inflow tube 69 to the solid electrolyte cylindrical body 30 and the downstream flow path 77 from the solid electrolyte cylindrical body 30 to the gas outflow pipe 68, While making the channel length different, the total length of the upstream channel and the downstream channel for each solid electrolyte cylindrical body was made constant.

  Therefore, in the oxygen pump, the flow rate control mechanism M causes the flow path length to be different between the upstream side and the downstream side for each of the solid electrolyte cylindrical bodies 30 arranged side by side. After that, the lengths of the flow paths of the gas to be merged are matched. For this reason, the flow rate of the gas flowing through each solid electrolyte cylindrical body 30 is the same, and the processing capability of each solid electrolyte cylindrical body 30 is the same.

  As another flow rate control mechanism M, the gas branch pipe 62, the branch path 56, the gas junction pipe 61, and the flow path shapes and dimensions of the junction path 55 are adjusted. The pipe resistance of the path leading to the gas outflow pipe 68 via the pipe may be made equal among the solid electrolyte cylindrical bodies 30. In this case, the flow rate of the gas flowing through each solid electrolyte cylindrical body 30 is the same, and the processing capability of each solid electrolyte cylindrical body 30 is the same.

  According to the present invention, since the plurality of solid electrolyte cylindrical bodies 30 arranged along the vertical direction are arranged side by side at a predetermined pitch on the vertical plane, the gas processing capacity can be improved. Moreover, since the gas flow rate of each solid electrolyte cylindrical body 30 is made the same by the flow rate control mechanism M, the gas processing capacity in each solid electrolyte cylindrical body 30 becomes the same. For this reason, a large amount of high-quality purified gas controlled to the target oxygen partial pressure can be purified at a time.

  The upstream channel 76 from the gas inflow tube 69 to the solid electrolyte cylindrical body 30 and the downstream channel 77 from the solid electrolyte cylindrical body 30 to the gas outlet tube 68 have different channel lengths. In addition, by making the total length of the upstream flow path 76 and the downstream flow path 77 for each solid electrolyte cylindrical body 30 constant, or the gas branch pipe 62, the branch path 56, the gas junction pipe 61, the junction By adjusting the flow path shape and dimensions of the path 55, the pipe resistance of the path from the gas inflow pipe 69 to the gas outflow pipe 68 via each solid electrolyte cylindrical body 30 is reduced to each solid electrolyte cylindrical body 30. Therefore, it is possible to improve the accuracy of making the gas flow rate of each solid electrolyte cylindrical body 30 the same.

  By the way, a part of solid electrolyte and a part of electrode may peel off by thermal expansion or the like. However, even in such a case, in the present invention, the gas flows into the solid electrolyte cylindrical body 30 from below, so that the treated gas flows out from above, and the solid electrolyte or the like peeled off is below this Stay on the gas supply side after treatment. For this reason, pure purified gas can be supplied, and operations in the sample preparation chamber or the like on the gas supply side are stabilized.

Although it is a reference example, the heating means 31 can be configured by a heating wire (heater ) that surrounds the solid electrolyte cylindrical body 30 without using the planar heater 43 . In this case, even if a plurality of ring-shaped heating wires are arranged at a predetermined pitch along the axial direction, one heating wire is wound around the solid electrolyte cylindrical body 30 in a spiral shape (coil shape). It may be what you did. Thus, if the heating wire made into the surrounding shape is used, the solid electrolyte cylindrical body 30 can be heated from the whole circumference direction, and efficient heating becomes possible.

Further, as another reference example, each solid electrolyte cylindrical body 30 is arranged on one vertical plane. However, as another embodiment, a plurality of solid electrolyte cylindrical bodies 30 are columnar solid electrolyte cylindrical bodies. You may comprise a body bundle. In this case, a plurality of solid electrolyte cylindrical bodies 30 can be disposed along the circumferential direction, or a plurality of solid electrolyte cylindrical bodies 30 can be disposed so as to be bundled. Also, when arranging along the circumferential direction,
It may be arranged on a plurality of concentric circles.

  If a plurality of solid electrolyte cylindrical bodies 30 constitutes a columnar solid electrolyte cylindrical bundle, a heating wire 31 is disposed on the outer peripheral side of the solid electrolyte cylindrical bundle as a heating means 31 and surrounds the outer periphery ( Heater), a heating wire (heater) disposed on the inner peripheral side and surrounding the inner periphery, or a heating wire (heater) surrounding both the outer peripheral side and the inner peripheral side can be used. For this reason, each solid electrolyte cylindrical body 30 of the solid electrolyte cylindrical body bundle can be heated more efficiently, and moreover, since a plurality of solid electrolyte cylindrical bodies are provided, the purification ability can be improved.

  As described above, the embodiments of the present invention have been described. However, the present invention is not limited to the above-described embodiments, and various modifications are possible. For example, the number of solid electrolyte cylindrical bodies 30 can be increased or decreased arbitrarily. If the amount is too large, the entire apparatus becomes large, and if the amount is too small, the processing capacity cannot be improved. For this reason, although it changes with the diameter dimension, length dimension, etc. of the solid electrolyte cylindrical body 30, about five are preferable like the example of a figure. Further, each solid electrolyte cylindrical body 30 may be arranged along the circumferential direction or arranged so as to be bundled without being arranged on one vertical plane, or arranged on the vertical plane. Even in the case of non-uniform pitch, the pitch may be unequal. Furthermore, you may arrange | position along a horizontal direction etc., without arrange | positioning along an up-down direction. In the embodiment, the gas inflow pipe 69 side connected to the lower branch pipe 62 is elongated, but the gas outflow pipe 69 side connected to the upper junction pipe 61 may be elongated. Further, in the embodiment, after the gas flows in from the lower gas inflow pipe 69 and is processed in each solid electrolyte cylindrical body 30, it flows out from the upper gas outflow pipe 69. After the gas flows in from the upper connecting pipe and is processed in each solid electrolyte cylindrical body 30, the gas may flow out from the lower gas inflow pipe 69.

  As the heater 43 of the heating means 31, the solid electrolyte cylindrical body 30 is sandwiched in the embodiment, but may be disposed on either the front side or the rear side. In addition, a planar heater 43 may be used as the heating means 31 for a column-shaped solid electrolyte cylindrical body bundle constituted by a plurality of solid electrolyte cylindrical bodies 30. Even when sandwiched between two flat heaters 43, one flat heater 43 may be disposed on either the front side or the rear side, and further, four flat planes may be provided. The solid electrolyte cylindrical bundle may be arranged so as to surround the four directions of the front, rear, left and right with the heater 43 having a shape.

It is a principal part front view inside the oxygen pump which shows embodiment of this invention. It is a cross-sectional side view of the oxygen pump. It is a simplified diagram of a conventional oxygen partial pressure control device. It is explanatory drawing of the principle of an oxygen pump.

Explanation of symbols

30 Solid electrolyte cylindrical body 31 Heating means 55 Combined flow path 56 Branch path 61 Gas merge pipe 62 Gas branch pipe 68 Gas outflow pipe 69 Gas inflow pipe 76 Upstream flow path 77 Downstream flow path M Flow rate control mechanism

Claims (1)

In an oxygen pump comprising a solid electrolyte cylindrical body having oxygen ion conductivity, electrodes disposed on the inner and outer surfaces of the solid electrolyte cylindrical body, and heating means for heating the solid electrolyte cylindrical body,
A plurality of solid electrolyte cylinders arranged vertically along the vertical direction are arranged in parallel at a predetermined pitch on one vertical plane through a flow rate control mechanism that makes the gas flow rate the same, and The heating means is composed of a pair of flat heaters, and a plurality of solid electrolyte cylinders disposed on one vertical plane are sandwiched between the pair of flat heaters, and the flow rate The control mechanism is connected to a gas branch pipe to which a gas inflow pipe is connected, a plurality of branch paths for independently supplying gas from the gas branch pipe to each solid electrolyte cylindrical body, and a gas outflow pipe. A gas merging pipe, and a plurality of merging passages for supplying gas from each solid electrolyte cylindrical body to the gas merging pipe independently, an upstream flow path from the gas inflow pipe to the solid electrolyte cylindrical body, and a solid In the downstream flow path from the electrolyte cylinder to the gas outflow pipe In addition, the flow lengths are made different, and the total length of the upstream flow path and the downstream flow path for each solid electrolyte cylindrical body is made constant, and gas flows into each solid electrolyte cylindrical body from below. oxygen pump, characterized in that cause.

Images