Oxygen concentrator

Abstract

To suppress life deterioration of an absorber and improve the stability of oxygen supply, thereby enhancing productivity.SOLUTION: An oxygen concentrator 1 comprises: a compressor 5 for absorbing a gas through a line L1 and applying pressure; an electromagnetic valve V1 for switching the supply destination of the pressurized gas output from the compressor 5; a first absorption part 8A and a second absorption part 8B that receive supply of the pressurized gas from one end side and absorb nitrogen and moisture from the pressurized gas; a feedback line L9 connecting the other end side of the first absorption part 8A and the other end side of the second absorption part 8B; a controller 13 that controls the electromagnetic valve V1, supplies the pressurized gas to one of the first absorption part 8A and the second absorption part 8B, and supplies an oxygen concentrated gas discharged from the absorption part to the other of the first absorption part 8A and the second absorption part 8B via the feedback line L9; and a circulation line L10 for supplying a discharged gas discharged from the other to an absorption side of the compressor 5.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to an oxygen concentrator. [Background technology]

[0002] For example, concentrated oxygen is produced by separating nitrogen and moisture from air using an adsorbent such as zeolite using a PSA method.

[0003] For example, Patent Document 1 describes a method of reducing the pressure of one adsorption bed using a compressor to perform regeneration. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-246001 Summary of the Invention [Problem to be solved by the invention]

[0005] For example, when the air is in a high-temperature, high-humidity state, large amounts of nitrogen and moisture are adsorbed and accumulated during the adsorption process. This can lead to deterioration of adsorption performance and frequent replacement of zeolites and other components. Patent Document 1 describes regeneration by reducing pressure using a compressor. However, because Patent Document 1 uses a single adsorption bed, concentrated oxygen cannot be produced in the adsorption bed during regeneration, making it difficult to provide a stable oxygen supply and improving the productivity of concentrated oxygen. Because it is difficult to provide a stable oxygen supply, it is difficult to improve the added value of a PSA system (oxygen concentrator) by improving basic performance, such as stabilizing the oxygen concentration or extending the life of the adsorbent without preventing deterioration of its adsorption performance. This makes it difficult to improve productivity.

[0006] In view of the above problems, an object of the present invention is to provide an oxygen concentrator that can suppress a decrease in the lifespan of an adsorption device, improve the stability of oxygen supply, and increase productivity. [Means for solving the problem]

[0007] In order to solve the above problems, an oxygen concentrator according to a first aspect of the present invention includes a first line, a compressor that draws in and pressurizes gas through the first line, a solenoid valve to which the pressurized gas output from the compressor is supplied and which switches the supply destination of the pressurized gas, a first adsorption unit to which the pressurized gas is supplied from one end via the solenoid valve and which adsorbs nitrogen and moisture from the pressurized gas, a second adsorption unit to which the pressurized gas is supplied from one end via the solenoid valve and which adsorbs nitrogen and moisture from the pressurized gas, a feedback line connecting the other end of the first adsorption unit to the other end of the second adsorption unit, a control device that controls the solenoid valve to supply the pressurized gas to one of the first adsorption unit or the second adsorption unit and supply the oxygen-enriched gas discharged from the adsorption unit to the other of the first adsorption unit or the second adsorption unit via the feedback line, and a circulation line that supplies the exhaust gas discharged from the other adsorption unit to the intake side of the compressor.

[0008] In a second aspect of the present invention, the compressor further includes a second line connected to the intake port of the compressor and an intake electromagnetic valve connecting either the first line or the circulation line.

[0009] In addition, in a third aspect of the present invention, the system further includes a bypass line connecting the first line and the circulation line, and a check valve provided in the bypass line, with the first line side as its primary side and the circulation line side as its secondary side.

[0010] In addition, in a fourth aspect of the present invention, the device further comprises an orifice provided in the bypass line to limit the flow rate from the primary side to the secondary side.

[0011] In addition, in a fifth aspect of the present invention, during the period in which the pressurized gas is supplied to one of the adsorption sections, the control device controls the intake solenoid valve to switch from a state in which the second line and the circulation line are connected to a state in which the second line and the first line are connected.

[0012] In a sixth aspect of the present invention, the first line takes in gas through an activated carbon filter.

[0013] In addition, in a seventh aspect of the present invention, the apparatus further comprises a drain tank that is provided in the middle of a third line that connects the compressor and the solenoid valve, and that drains water from the pressurized gas.

[0014] In addition, in an eighth aspect of the present invention, the control device has the function of adjusting between a first state in which the first line and the second line are connected by the intake solenoid valve and a second state in which the circulation line and the second line are connected by the intake solenoid valve, thereby making it possible to adjust the oxygen concentration of the oxygen-enriched gas generated in the adsorption section.

[0015] In a ninth aspect of the present invention, the control device is capable of adjusting a time for executing the first state and a time for executing the second state.

[0016] In addition, in a tenth aspect of the present invention, the control device controls the solenoid valve to start supplying the pressurized gas to one of the adsorption sections, and controls the intake solenoid valve to connect the first line and the second line for a first time, and then, while the pressurized gas is being supplied to the one of the adsorption sections, controls the intake solenoid valve to connect the circulation line and the second line for a second time.

[0017] In addition, in an eleventh aspect of the present invention, the shorter the ratio of the first time to the period during which the pressurized gas is supplied to one of the adsorption sections, the more likely it is that the oxygen concentration of the oxygen-enriched gas generated will be reduced, and the longer the ratio of the second time to the period, the more likely it is that the oxygen concentration of the oxygen-enriched gas generated will be increased.

[0018] In addition, in a twelfth aspect of the present invention, the system further includes a discharge line connected at one end to the circulation line and discharging the gas in the circulation line to the outside of the system via a check valve, and an orifice provided in the discharge line and limiting the flow rate of the gas being discharged.

[0019] An oxygen concentrator according to a thirteenth aspect of the present invention includes a first line, a compressor that takes in outside air through the first line and pressurizes it, a switching valve that switches between an adsorption process in which the pressurized gas output from the compressor is supplied to an adsorption unit, and the adsorption unit adsorbs nitrogen and moisture and discharges oxygen-enriched gas, and a regeneration process in which the adsorbed nitrogen and moisture are discharged from the adsorption unit, a purge unit that supplies the oxygen-enriched gas discharged in the adsorption process to the adsorption unit in the regeneration process and purges nitrogen and moisture from the adsorption unit, and a switching valve that switches between an adsorption process and a regeneration process in which the oxygen-enriched gas discharged in the adsorption process is discharged from the adsorption unit. and a circulation line that supplies the exhaust gas discharged from the adsorption section to the intake side of the compressor. When the exhaust gas flowing through the circulation line changes from a state in which it has more nitrogen than the outside air to a state in which it has more oxygen than the outside air, the exhaust gas supplied to the compressor is made to have more nitrogen than the outside air, thereby decreasing the oxygen concentration of the oxygen-enriched gas, and the exhaust gas supplied to the compressor is made to have more oxygen than the outside air, thereby increasing the oxygen concentration of the oxygen-enriched gas. [Effects of the Invention]

[0020] According to the oxygen concentrator of the present invention, it is possible to suppress a decrease in the life of the adsorption device, improve the stability of oxygen supply, and increase productivity. [Brief explanation of the drawings]

[0021] [Figure 1] 1 is a diagram illustrating an example of the overall configuration of an oxygen concentrator according to a first embodiment of the present invention. [Figure 2] 2 is a timing chart showing an example of a processing flow of the oxygen concentrator of FIG. 1. [Figure 3]FIG. 10 is a diagram showing an example of the state of the oxygen concentrator during a period T2. [Figure 4] FIG. 10 is a diagram showing an example of the state of the oxygen concentrator during a period T3. [Figure 5] 10 is a timing chart showing an example of a processing flow of an oxygen concentrator according to a second embodiment of the present invention. [Figure 6] FIG. 4 is a diagram showing an example of the relationship between the intake-side oxygen concentration and the discharge-side oxygen concentration. [Figure 7] FIG. 2 is a diagram showing a modification of the overall configuration of the oxygen concentrator of FIG. DETAILED DESCRIPTION OF THE INVENTION

[0022] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. To facilitate understanding of the description, the same components in the drawings will be denoted by the same reference numerals as much as possible, and duplicate descriptions will be omitted where appropriate.

[0023] ===First Embodiment=== <Overall structure> FIG. 1 is a diagram schematically illustrating an example of the overall configuration of an oxygen concentrator 1 according to a first embodiment of the present invention. The oxygen concentrator 1 is also called an oxygen gas generator or a PSA (Pressure Swing Adsorption). The oxygen concentrator 1 is a device that separates nitrogen and moisture from a gas (raw material gas) to generate a gas with a high oxygen concentration. The gas is, for example, the air (outside air) in the surrounding environment of the oxygen concentrator 1. Note that the gas is not limited to the above as long as it contains oxygen. The gas may also contain acidic gases such as ozone gas and chlorine-based gases.

[0024] 1, the oxygen concentrator 1 mainly comprises an activated carbon filter 3, a solenoid valve V2, a compressor 5, a drain tank 6, a solenoid valve V1, an adsorption device 8, a feedback line L9, a circulation line L10, a bypass line L11, an orifice OR2, an air chamber 12, and a control device 13. Note that the specific configuration of the oxygen concentrator 1 is not limited to that shown in FIG.

[0025] The activated carbon filter 3 is provided at one end of the line L1, which serves as the first line. The activated carbon filter 3 is a filter member that uses activated carbon. For example, gas containing ozone gas or chlorine-based gas is taken in from the outside air as a raw gas through the activated carbon filter 3, and the ozone gas, chlorine-based gas, etc. are removed, and the gas is taken in the line L1. This makes it possible to suppress corrosion damage to resin materials used in the system. Furthermore, the oxygen concentrator 1 can be used in various environments, such as a swimming pool or a bathroom.

[0026] The solenoid valve V2 is an intake solenoid valve that connects the intake port 5a of the compressor 5 to either the line (first line) L1 or the circulation line L10. The solenoid valve V2 is a three-port type having ports NO, NC, and COM. Port NO is connected to the line L1, and port NC is connected to the circulation line L10 (described later). Port COM is connected to the line L2 (second line). The solenoid valve V2 opens either port NO or port NC to port COM. That is, when port NO is selected, the lines L1 and L2 are open, and when port NC is selected, the circulation line L10 and L2 are open. That is, depending on the state of the solenoid valve V2, it is controlled whether outside air is supplied to the compressor 5 via line L1 or gas and moisture from the adsorber 8 are supplied to the compressor 5 via the circulation line L10.

[0027] The compressor 5 takes in air and pressurizes (compresses) it. Specifically, the compressor 5 has an intake port 5a connected to a line L2, and takes in gas from, for example, a line L1 and pressurizes it. The gas pressurized by the compressor 5 is referred to as "compressed gas." The pressurized gas is output to a line L3, which serves as a third line connected to the discharge port 5b of the compressor 5.

[0028] The water drain tank 6 is connected to the middle of the line L3. That is, the water drain tank 6 is provided between the compressor 5 and the solenoid valve V1. The water drain tank 6 drains water from the pressurized gas flowing through the line L3. That is, the water drain tank 6 reduces the amount of moisture contained in the pressurized gas and outputs the pressurized gas to the solenoid valve V1. The removed moisture is temporarily accumulated in the water drain tank 6. The accumulated moisture is discharged by the solenoid valve V3. For example, the accumulated moisture is periodically discharged by the solenoid valve V3.

[0029] The solenoid valve V1 is supplied with pressurized gas output from the compressor 5 and switches the supply destination of the pressurized gas. The solenoid valve V1 is a four-port type (four-way, three-position type) and has ports P1, P2, P3, and P4. The solenoid valve V1 switches the connection states of the four ports. Specifically, the solenoid valve V1 switches between three connection states. In connection state S1, ports P1 and P3 are connected, and ports P2 and P4 are connected. In connection state S2, ports P3 and P4 are connected. In connection state S3, ports P1 and P4 are connected, and ports P2 and P3 are connected. The flow of gas is controlled by the solenoid valve V1. The example in FIG. 1 shows a case where the solenoid valve V1 is in connection state S2. The solenoid valve V1 is, for example, a pilot-operated type.

[0030] The adsorption device 8 adsorbs nitrogen and moisture from pressurized gas. The adsorption device 8 includes a first adsorption unit 8A and a second adsorption unit 8B. The first adsorption unit 8A and the second adsorption unit 8B use an adsorbent, such as zeolite, to adsorb nitrogen and moisture from the pressurized gas supplied from one end of the adsorption device. The first adsorption unit 8A is connected to port P4 of the solenoid valve V1 via line L4, and the second adsorption unit 8B is connected to port P3 of the solenoid valve V1 via line L5. The first adsorption unit 8A and the second adsorption unit 8B have similar configurations, but are supplied with pressurized gas at different times. They alternate between an adsorption process and a regeneration process. The adsorption process adsorbs nitrogen and moisture from the pressurized gas and discharges the resulting oxygen-enriched gas. The oxygen-enriched gas produced in the adsorption process is a dry gas with a high oxygen concentration. The nitrogen and moisture adsorbed in the adsorption process are accumulated. In particular, when the gas compressed by the compressor 5 is in a high-temperature, high-humidity state, nitrogen and moisture are likely to accumulate. The regeneration process is a process in which the adsorbed and accumulated nitrogen and moisture are discharged as exhaust gas together with the supplied gas (oxygen-enriched gas). When the first adsorption section 8A or the second adsorption section 8B (one side) that performs the adsorption process becomes the "adsorption section," the second adsorption section 8B or the first adsorption section 8A (the other side) that performs the regeneration process on the opposite side becomes the "regeneration section." In other words, when the first adsorption section 8A is the adsorption section, the second adsorption section 8B becomes the regeneration section, and when the second adsorption section 8B is the adsorption section, the first adsorption section 8A becomes the regeneration section.

[0031] Whether the first adsorption unit 8A or the second adsorption unit 8B functions as an adsorption unit or a regeneration unit is controlled by the state of the solenoid valve V1. Specifically, of the first adsorption unit 8A and the second adsorption unit 8B, one that receives pressurized gas functions as an adsorption unit, and the other functions as a regeneration unit. That is, the adsorption units are pressurized by the compressor 5. When the solenoid valve V1 is in the connected state S1, the first adsorption unit 8A functions as a regeneration unit, and the second adsorption unit 8B functions as an adsorption unit. When the solenoid valve V1 is in the connected state S3, the first adsorption unit 8A functions as an adsorption unit, and the second adsorption unit 8B functions as a regeneration unit. When the solenoid valve V1 is in the connected state S2, neither the first adsorption unit 8A nor the second adsorption unit 8B functions as an adsorption unit or a regeneration unit, and they are in a pressure-equalizing state. Creating a pressure-equalizing state stabilizes the oxygen concentration. For example, the pressure-equalizing state (connected state S2) should last for about one second.

[0032] The first adsorption unit 8A is connected to a line L6 provided with a check valve 17A serving as a first check valve. The check valve 17A has a primary side on the side of the first adsorption unit 8A and a secondary side on the opposite side. When the pressure on the primary side is higher than the pressure on the secondary side, the check valve 17A allows gas to flow from the primary side to the secondary side and prevents backflow from the secondary side to the primary side. The second adsorption unit 8B is connected to a line L7 provided with a check valve 17B serving as a second check valve. The check valve 17B has a primary side on the side of the second adsorption unit 8B and a secondary side on the opposite side. When the pressure on the primary side is higher than the pressure on the secondary side, the check valve 17B allows gas to flow from the primary side to the secondary side and prevents backflow from the secondary side to the primary side. Note that the smaller the pressure difference between the primary and secondary sides, the more likely backflow will occur in the check valves 17A and 17B. For this reason, as will be described later, the provision of orifice OR2 makes it easier to clearly create a differential pressure between the primary and secondary sides of check valve 17A and check valve 17B, thereby effectively preventing backflow. Specifically, the provision of orifice OR2 prevents the secondary pressure of check valve 17A and check valve 17B from becoming too low (approaching the primary pressure), effectively preventing backflow. The secondary side of check valve 17A on line L6 and the secondary side of check valve 17B on line L7 join together and are connected to line L8.

[0033] The feedback line L9 connects the line L6 and the line L7. Specifically, the feedback line L9 connects the other end of the first adsorption unit 8A to the other end of the second adsorption unit 8B. That is, the feedback line L9 connects the first adsorption unit 8A and the check valve 17A to the second adsorption unit 8B and the check valve 17B. A portion of the oxygen-enriched gas discharged from either the first adsorption unit 8A or the second adsorption unit 8B is fed back to the other. The feedback line L9 is provided with an orifice OR1 as a first orifice, which limits the flow rate (pressure) of the gas flowing through the feedback line L9.

[0034] For example, when the solenoid valve V1 is in the connected state S1, the oxygen-enriched gas generated in the second adsorption unit 8B serving as an adsorption unit flows through line L7 to line L8, and a portion of the oxygen-enriched gas in line L7 flows to the feedback line L9. This causes the oxygen-enriched gas generated in the second adsorption unit 8B serving as an adsorption unit to be fed back to the first adsorption unit 8A serving as a regeneration unit. Because the pressure in the primary side of the check valve 17B is higher than that in the secondary side, the check valve 17B sends the oxygen-enriched gas generated in the second adsorption unit 8B to the air chamber 12 (described below). Because the pressure in the primary side of the check valve 17A is lower than that in the secondary side, backflow from the secondary side to the primary side is suppressed. Therefore, the oxygen-enriched gas that passes through the feedback line L9 is prevented from flowing out by the check valve 17A and instead flows into the first adsorption unit 8A. As a result, the oxygen-enriched gas that has flowed in from the bottom of the first adsorption section 8A flows out as exhaust gas from the top of the first adsorption section 8A together with the accumulated nitrogen and moisture. The exhaust gas is circulated to a circulation line L10 (described later) by a solenoid valve V1.

[0035] One end of the circulation line L10 is connected to port P2 of the solenoid valve V1, and the other end is connected to port NC of the solenoid valve V2. The circulation line L10 supplies the exhaust gas output from the regeneration unit to the intake side of the compressor 5. Specifically, when the solenoid valve V1 is in the connected state S1, the exhaust gas discharged from the first adsorption unit 8A flows into the circulation line L10. On the other hand, when the solenoid valve V1 is in the connected state S3, the exhaust gas discharged from the second adsorption unit 8B flows into the circulation line L10.

[0036] The circulation line L10 connects the regeneration unit and the compressor 5 in an open state, so that the gas (oxygen-enriched gas) inside the regeneration unit is extracted by the compressor 5 via the circulation line L10. Specifically, the gas inside the regeneration unit is actively extracted by the compressor 5 at a pressure lower than atmospheric pressure. The exhaust gas supplied to the compressor 5 is pressurized in the compressor 5 and supplied again to the adsorption device 8. In this way, the exhaust gas circulates through the system via the circulation line L10.

[0037] Furthermore, the circulation line L10 is provided with a line L12. The line L12 is a line that releases the exhaust gas flowing through the circulation line L10 via a silencer 20. A check valve 21 is provided in the line L12 between the circulation line L10 and the silencer 20. The check valve 21 has a primary side on the circulation line L10 side and a secondary side on the silencer 20 side, and when the pressure on the primary side is higher than the pressure on the secondary side, it allows gas to flow from the primary side to the secondary side and prevents backflow from the secondary side to the primary side.

[0038] The bypass line L11 connects the line L1 and the circulation line L10. Specifically, the bypass line L11 connects the activated carbon filter 3 and the solenoid valve V2 in the line L1 to the solenoid valve V2 and the solenoid valve V1 in the circulation line L10. The bypass line L11 supplies gas (outside air) from the line L1 to the circulation line L10.

[0039] The bypass line L11 is provided with a check valve 22. The check valve 22 has the line L1 as its primary side and the circulation line L10 side as its secondary side, and when the pressure on the primary side is higher than the pressure on the secondary side, the check valve 22 allows gas to flow from the primary side to the secondary side and prevents backflow from the secondary side to the primary side.

[0040] The bypass line L11 is also provided with an orifice OR3. The orifice OR3 limits the flow rate (pressure) of the gas flowing through the bypass line L11. Specifically, the orifice OR3 adjusts the amount of gas supplied from the bypass line L11 to the circulation line L10 so as to compensate for the amount of gas exhausted through the circulation line L10 and circulated to the compressor 5. The orifice OR3 has an orifice diameter of, for example, about 1.0 to 1.6 mm.

[0041] In this way, the exhaust gas discharged from the regeneration unit flows into the circulation line L10, and at the same time, gas (outside air) is supplied from the bypass line L11 to the circulation line L10 via the activated carbon filter 3, and the gas amounts are summed and flow to the compressor 5. As a result, not only the exhaust gas but also the outside air flows to the compressor 5, which prevents a shortage of the overall gas amount and ensures the production amount of oxygen-enriched gas.

[0042] Orifice OR2 is provided in line L8 as a second orifice. Specifically, orifice OR2 is provided between the confluence (junction) of lines L6 and L7 and the air chamber 12. Orifice OR2 limits the flow rate (pressure) of the gas flowing through line L8. Orifice OR2 also adjusts the pressure on the secondary side of check valve 17A and the pressure on the secondary side of check valve 17B. The orifice diameter of orifice OR2 is preferably equal to or larger than the orifice diameter of orifice OR1. For example, the orifice diameter of orifice OR2 is 0.7 mm, and the orifice diameter of orifice OR1 is 0.6 mm. When the pressure difference between the primary and secondary sides of check valve 17A or check valve 17B is small, gas may flow from both directions, preventing the check valve 17A or 17B from functioning as its intended check mechanism. For example, when the solenoid valve V1 switches between the adsorption and regeneration sections of the first adsorption section 8A and the second adsorption section 8B, the pressures on the primary and secondary sides of the check valve 17A and 17B fluctuate, temporarily creating a small pressure difference between the primary and secondary sides. Specifically, when the solenoid valve V1 is in the connected state S1, oxygen-enriched gas generated in the second adsorption section 8B flows to the first adsorption section 8A. However, when the solenoid valve V1 switches, the pressure on the secondary side of the check valve 17A may drop excessively, potentially causing backflow through the check valve 17A. Such backflow reduces the amount of oxygen-enriched gas sent to the air chamber 12. However, the orifice OR2 prevents the pressure on the secondary side of the check valve 17A and 17B from becoming too low, thereby preventing backflow through the check valve 17A and 17B. This prevents the oxygen-enriched gas from flowing back after passing through the adsorption section, allowing the oxygen-enriched gas to be stably sent to the air chamber 12. Furthermore, gas has a cushioning effect, and if the orifice OR2 is located farther away from the confluence, the volume of the path from the check valve 17A or 17B to the orifice OR2 increases. A larger volume increases the likelihood of a decrease in flow rate due to the cushioning effect. To effectively suppress pressure fluctuations on the secondary side of the check valve 17A or 17B against the cushioning effect, the orifice OR2 is preferably located in line L8 closer to the confluence of lines L6 and L7 than the air chamber 12.That is, it is preferable that the orifice OR2 is provided closer to the confluence than the midpoint that divides the entire length of the line L8 between the air chamber 12 and the confluence of the lines L6 and L7 into two equal parts.

[0043] The air chamber 12 is connected to the downstream side of the line L8 and is supplied with the oxygen-enriched gas discharged from the adsorption section of the adsorption device 8. A regulator 24 is provided downstream of the air chamber 12, and the oxygen-enriched gas is output to the outside via the regulator 24. The regulator 24 controls the pressure of the oxygen-enriched gas output to the outside. For example, the regulator 24 is a relief type, and is controlled so that the discharge pressure is constant.

[0044] The control device 13 is an information processing device (computer) that controls each part of the oxygen concentrator 1.

[0045] Specifically, the control device 13 controls the solenoid valve V1 to supply pressurized gas to the adsorption unit. That is, the control device 13 switches the connection state of the solenoid valve V1. The control device 13 controls the solenoid valve V1 to supply pressurized gas to either the first adsorption unit 8A or the second adsorption unit 8B. Then, the oxygen-enriched gas discharged from the adsorption unit is supplied to the other regeneration unit (the first adsorption unit 8A or the second adsorption unit 8B) via the feedback line L9. Then, during the period in which the pressurized gas is being supplied, the control device 13 controls the solenoid valve V2 to switch from a state in which the line L2 (the intake port 5a of the compressor 5) and the circulation line L10 are connected to a state in which the line L2 and the line L1 are connected. For example, when the solenoid valve V1 is controlled to set the first adsorption unit 8A as the regeneration unit, the control device 13 controls the solenoid valve V2 to switch from a state in which the line L2 and the circulation line L10 are connected to a state in which the line L2 and the line L1 are connected.

[0046] 1, the control device 13 includes a control unit 30, a communication unit 31, and a storage unit 32. The control unit 30 mainly includes a CPU (Central Processing Unit) 33 and a memory .

[0047] In the control unit 30, the CPU 33 executes predetermined programs stored in the memory 34 or the storage unit 32, etc., thereby functioning as various functional components described below. The memory 34 is a computer-readable storage medium, and may be composed of at least one of, for example, a random access memory (RAM), a read-only memory (ROM), an erasable program read-only memory (EPROM), an electrically erasable program read-only memory (EEPROM), etc. The memory 34 can store various types of data, such as programs required to execute processing.

[0048] The communication unit 31 is configured with a communication interface for communicating with an external device.

[0049] The storage unit 32 is a computer-readable instruction recording medium, and is configured, for example, with a hard disk or a solid state drive. The storage unit 32 stores various programs and information required for executing processes in the control unit 30, as well as information on the processing results. Note that other examples of non-transitory computer-readable instruction recording media include portable recording media such as magnetic tape, flexible disks, optical disks, digital versatile disks, Blu-ray disks, magneto-optical disks, memory cards, and USB memory.

[0050] The control device 13 can also be realized using an information processing device such as a dedicated or general-purpose computer or a microcomputer. The control device 13 may be configured with a single information processing device or multiple information processing devices. FIG. 1 only shows a portion of the main hardware configuration of the control device 13, and the control device 13 may have other configurations. For example, the control device 13 may further include an input unit (not shown) and a display unit (not shown). The input unit is an input device (e.g., a keyboard, a mouse, etc.) that accepts input from the outside. The input unit accepts user operations and inputs the operations to the control device 13. The display unit is a display device (e.g., a display, etc.) that outputs to the outside. The display unit outputs characters and images. The control device 13 may have an input unit and a display unit integrated together (e.g., a touch panel).

[0051] <Processing flow> Fig. 2 is a timing chart (time chart) showing an example of the processing flow of the oxygen concentrator 1 according to this embodiment. Fig. 2 shows the operation of each part in chronological order. Fig. 2 shows the state of solenoid valve V1, the state of solenoid valve V2, the state of first adsorption unit 8A, the state of second adsorption unit 8B, and the state of solenoid valve V3.

[0052] The solenoid valve V1 is controlled to switch between a connected state S1, a connected state S2, and a connected state S3. The solenoid valve V2 is controlled to switch between a state in which port NO is selected and a state in which port NC is selected. The first adsorption unit 8A is controlled to switch between an adsorption process, a pressure equalization process, and a regeneration process. The second adsorption unit 8B is controlled to switch between an adsorption process, a pressure equalization process, and a regeneration process. The solenoid valve V3 is controlled to switch between ON and OFF.

[0053] During period T1, the solenoid valve V1 is in the connected state S3, which causes the first adsorption unit 8A to enter the adsorption process and the second adsorption unit 8B to enter the regeneration process. FIG. 3 shows the state of the oxygen concentrator 1 during period T1 (specifically, period T2). Pressurized gas is supplied to the first adsorption unit 8A, and oxygen-enriched gas is generated in the first adsorption unit 8A and supplied to the air chamber 12. A portion of the oxygen-enriched gas generated in the first adsorption unit 8A is fed back from the secondary side of the first adsorption unit 8A to the secondary side of the second adsorption unit 8B. During period T2, which is the first half of period T1, the solenoid valve V2 selects port NC. Period T2 (the first half of period T1) lasts, for example, 5 to 20 seconds. This causes the exhaust gas discharged from the second adsorption unit 8B to circulate to the compressor 5 through the circulation line L10. That is, the exhaust gas from the second adsorption section 8B, which is in the regeneration process, is actively drawn (sucked) by the compressor 5, and the oxygen-enriched gas for regeneration flows into the second adsorption section 8B, discharging the accumulated nitrogen and moisture. This restores the adsorption function of the second adsorption section 8B. Furthermore, if only the gas discharged from the second adsorption section 8B were to flow, the amount of gas circulating to the compressor 5 would decrease, but outside air is replenished to the circulation line L10 via the bypass line L11. This ensures that a sufficient amount of gas is supplied to the compressor 5, preventing a decrease in the amount of oxygen-enriched gas produced.

[0054] Returning to FIG. 2, when the period T1 transitions to period T3, which is the latter half of period T1, the state of solenoid valve V2 switches. Period T3 is, for example, about 5 to 10 seconds. FIG. 4 shows the state of oxygen concentrator 1 during period T1 (specifically, period T3). Specifically, during period T3 (the latter half of period T1), solenoid valve V2 selects port NO, and exhaust gas does not circulate, but gas is supplied to compressor 5 through line L1. In other words, compressor 5 draws in only outside air through activated carbon filter 3. The exhaust gas is released outside the system through line L12.

[0055] Returning to FIG. 2, during period T4, the solenoid valve V1 is in the connected state S2. This places the first adsorption portion 8A and the second adsorption portion 8B in an open state. This causes the pressure states of the first adsorption portion 8A and the second adsorption portion 8B to be equalized. The pressure equalization time during period T4 is, for example, about 2 seconds. During period T4, the solenoid valve V2 is in a state in which port NO is selected.

[0056] Then, when the period T4 transitions to the period T5, the solenoid valve V1 switches to the connected state S1. Accordingly, the second adsorption unit 8B enters the adsorption process, and the first adsorption unit 8A enters the regeneration process. Therefore, oxygen-enriched gas is generated in the second adsorption unit 8B and supplied to the air chamber 12. During the period T6, which is the first half of the period T5, the solenoid valve V2 selects port NC. This causes the exhaust gas from the first adsorption unit 8A to circulate through the circulation line L10 to the compressor 5. Specifically, the compressor 5 actively extracts the exhaust gas from the first adsorption unit 8A, which is in the regeneration process, thereby discharging the nitrogen and moisture accumulated in the first adsorption unit 8A. Furthermore, if only the gas discharged from the first adsorption unit 8A were present, the amount of gas circulating to the compressor 5 would decrease. However, outside air is supplied to the circulation line L10 via the bypass line L11. Therefore, a sufficient amount of gas is supplied to the compressor 5, suppressing a decrease in the amount of oxygen-enriched gas produced.

[0057] Then, when the period moves to period T7, which is the second half of period T5, the state of solenoid valve V2 switches. Specifically, in period T7, solenoid valve V2 selects port NO, exhaust gas does not circulate, and gas is supplied to compressor 5 from line L1. In other words, compressor 5 takes in only outside air via activated carbon filter 3.

[0058] The above steps are repeated, and the adsorption step and the regeneration step are alternately carried out in the first adsorption section 8A and the second adsorption section 8B.

[0059] Furthermore, as shown in period T8, the solenoid valve V3 is periodically turned on, and the moisture accumulated in the drain tank 6 is drained to the outside. For example, the moisture is drained for about 1 to 5 seconds every 10 to 30 minutes.

[0060] <Action and effect> As described above, in this embodiment, the oxygen concentrator 1 includes a line L1 as a first line, a compressor 5 that draws in gas through the line L1 and pressurizes it, a solenoid valve V1 that receives the pressurized gas output from the compressor 5 and switches the supply destination of the pressurized gas, a first adsorption unit 8A that receives the pressurized gas from one end side via the solenoid valve V1 and adsorbs nitrogen and moisture from the pressurized gas, and a second adsorption unit 8B that receives the pressurized gas from one end side via the solenoid valve V1 and adsorbs nitrogen and moisture from the pressurized gas. a feedback line L9 connecting the other end of the first adsorption section 8A and the other end of the second adsorption section 8B; a control device 13 that controls the solenoid valve V1 to supply pressurized gas to either the first adsorption section 8A or the second adsorption section 8B and supplies the oxygen-enriched gas discharged from that adsorption section to the other first adsorption section 8A or second adsorption section 8B via the feedback line L9; and a circulation line L10 that supplies the exhaust gas discharged from the other section to the intake side of the compressor 5.

[0061] According to this configuration, the exhaust gas discharged from the regeneration unit can be sucked by the compressor 5, thereby effectively restoring the adsorption function of the first adsorption unit 8A and the second adsorption unit 8B. This suppresses a decrease in the lifespan of the adsorption device 8 and prevents frequent replacement of the first adsorption unit 8A and the second adsorption unit 8B. Furthermore, the first adsorption unit 8A and the second adsorption unit 8B are used to generate oxygen-enriched gas through an adsorption process, while the regeneration process allows for the recovery of the oxygen-enriched gas. This suppresses a decrease in the lifespan of the adsorption device 8 and improves productivity. By suppressing deterioration of the adsorption performance of the adsorption device 8, the device lifespan can be extended, and the productivity of the oxygen-enriched gas produced by the oxygen concentrator 1 can be improved. Furthermore, using two adsorption units (the first adsorption unit 8A and the second adsorption unit 8B) enables continuous oxygen supply, thereby improving the productivity of the oxygen-enriched gas produced by the oxygen concentrator 1.

[0062] In addition, this embodiment further includes a line L2 as a second line connected to the intake port 5a of the compressor 5, and a solenoid valve V2 as an intake solenoid valve that connects either the line L1 or the circulation line L10.

[0063] According to this configuration, it is possible to select whether to supply gas to the compressor 5 through the line L1 or to supply the exhaust gas to the compressor 5 through the circulation line L10.

[0064] In addition, this embodiment further includes a bypass line L11 that connects the line L1 and the circulation line L10, and a check valve 22 that is provided in the bypass line L11 and has the line L1 side as its primary side and the circulation line L10 side as its secondary side.

[0065] According to this configuration, gas can be replenished to the circulation line L10 from the bypass line L11, thereby preventing a decrease in the amount of oxygen-enriched gas produced.

[0066] In addition, this embodiment further includes an orifice OR3 that is provided in the bypass line L11 and limits the flow rate from the primary side to the secondary side.

[0067] This configuration prevents the amount of gas flowing in from the bypass line L11 from becoming larger than the amount of exhaust gas, making it difficult for the exhaust gas to be sucked into the compressor 5. In other words, the amount of gas can be replenished while circulating the exhaust gas to the compressor 5.

[0068] In addition, in this embodiment, during the period in which pressurized gas is supplied to one of the adsorption sections, the control device 13 controls the solenoid valve V2 to switch from a state in which the line L2 and the circulation line L10 are connected to a state in which the line L2 and the line L1 are connected.

[0069] According to this configuration, it is possible to effectively recover the regenerating section while suppressing a decrease in the amount of oxygen-enriched gas produced.

[0070] In this embodiment, the line L1 takes in gas through an activated carbon filter 3.

[0071] This configuration makes it possible to remove ozone gas and chlorine-based gases that may corrode and damage components, and allows the oxygen concentrator 1 to be used in a variety of environments.

[0072] In this embodiment, the system further includes a drain tank 6 that is provided in the middle of a line L3, which serves as a third line connecting the compressor 5 and the solenoid valve V1, and drains water from the pressurized gas.

[0073] According to this configuration, the amount of moisture in the pressurized gas is reduced in the upstream stage of the adsorption device 8, so that accumulation of moisture in the first adsorption section 8A and the second adsorption section 8B can be reduced.

[0074] === Second Embodiment === Next, a second embodiment will be described.

[0075] In the second embodiment, a case will be described in which the control device 13 has a function of adjusting the oxygen concentration of the oxygen-enriched gas. Note that a description of the same points as in the first embodiment will be omitted. Also, the second embodiment can be combined with the first embodiment.

[0076] When zeolite is used to adsorb nitrogen and moisture from pressurized gas to generate oxygen-enriched gas, the oxygen concentration may fluctuate depending on the usage conditions. For example, depending on the type of filler (zeolite), using a filler with good nitrogen and moisture adsorption performance may result in a high oxygen concentration. On the other hand, when generating ozone using concentrated oxygen, fluororesin is often used as a component, and when utilizing the non-flammable properties of fluororesin, the oxygen concentration should preferably be 95% or less. For this reason, it is necessary to adjust the oxygen concentration so that it does not become too high. Furthermore, if the filler is used for a long period of time, its regeneration efficiency will decrease due to deterioration over time, and sufficient nitrogen will not be discharged during regeneration, which may result in a decrease in the oxygen concentration the next time oxygen is generated. For example, the oxygen concentration required for ozone generation is approximately 80 to 99%, but if the filler deteriorates over time and the generated oxygen concentration decreases, the device will need to be stopped and the filler replaced, which will result in inconveniences such as the hassle of the replacement work and the inability to supply the necessary oxygen due to the device being stopped. In addition, for example, for medical use, an oxygen concentration of about 25 to 50% may be required. As such, the generated oxygen-enriched gas is required for various purposes, and it is preferable to be able to adjust the oxygen concentration according to the purpose.

[0077] In the second embodiment, the control device 13 has a function of adjusting the oxygen concentration of the generated oxygen-enriched gas. The generated oxygen-enriched gas can be used for various purposes. For example, as described above, if there is a possibility that the oxygen concentration will become high, the oxygen concentration can be adjusted to a lower level, and if there is a possibility that the oxygen concentration will become low, the oxygen concentration can be adjusted to a higher level.

[0078] Specifically, the control device 13 is capable of adjusting the balance between a state in which the line L1 and the line L2 are connected (hereinafter referred to as the "first state") and a state in which the circulation line L10 and the line L2 are connected (hereinafter referred to as the "second state") by using the solenoid valve V2. That is, the control device 13 is capable of adjusting the balance between the first state in which outside air is actively supplied to the compressor 5 through the line L1 and the second state in which exhaust gas flowing through the circulation line L10 is actively supplied to the compressor 5 by controlling the solenoid valve V2.

[0079] Specifically, the control device 13 is capable of adjusting the time for executing the first state and the time for executing the second state. For example, the control device 13 is capable of adjusting the time for executing each state, and adjustment is made by the user. The user sets each time so as to achieve a desired oxygen concentration before starting operation of the oxygen concentrator 1. Note that adjustment and setting may be made before or after shipment. In this way, the control device 13 switches between the first state and the second state based on the set time and generates oxygen-enriched gas. Note that each set time can be adjusted (changed) again by the user. Specifically, the user can set the times of periods W0, W1, W2, W3, W4, Wa, Wb, and We to the control device 13, as described below.

[0080] <Processing flow> Fig. 5 is a timing chart (time chart) showing an example of the processing flow of the control device 13 of the oxygen concentrator 1 according to this embodiment. Fig. 5 shows the operation of each part in chronological order. Fig. 5 shows the state of solenoid valve V1, the state of solenoid valve V2, the state of solenoid valve V3, the state of first adsorption unit 8A, and the state of second adsorption unit 8B.

[0081] The solenoid valve V1 is controlled to switch between a connected state S1, a connected state S2, and a connected state S3. The solenoid valve V1 is not limited to a solenoid valve and may be a switching valve. That is, the switching valve switches between an adsorption process in which pressurized gas output from the compressor 5 is supplied to an adsorption unit (first adsorption unit 8A or second adsorption unit 8B), nitrogen and moisture are adsorbed in the adsorption unit (first adsorption unit 8A or second adsorption unit 8B), and oxygen-enriched gas is discharged, and a regeneration process in which the adsorbed nitrogen and moisture are discharged from the adsorption unit (first adsorption unit 8A or second adsorption unit 8B). The solenoid valve V2 is controlled to switch between a state in which port NO is selected and a state in which port NC is selected. The solenoid valve V2 is not limited to a solenoid valve and may be a switching valve. The solenoid valve V3 is controlled to switch between ON and OFF. The first adsorption unit 8A is controlled to switch between an adsorption process, a pressure equalization process, and a regeneration process. The second adsorption section 8B is controlled to switch between an adsorption process, a pressure equalization process, and a regeneration process.

[0082] Furthermore, the control device 13 executes each process during each of the periods W0, W1, W2, W3, W4, Wa, Wb, and Wec set by the user.

[0083] First, as shown in a period W0, before the compressor 5 starts operating, the solenoid valve V3 is turned on to discharge water, and the pressure in the water drain tank 6 is released.

[0084] Then, as shown in period W1, the solenoid valve V1 is switched to the connected state S1, whereby the first adsorption unit 8A enters the regeneration process and the second adsorption unit 8B enters the adsorption process.

[0085] After the period W1, as shown in the period W2, the solenoid valve V1 enters the connected state S2, the first adsorption unit 8A and the second adsorption unit 8B enter the open state, and the pressures are equalized. Note that, during the period W2, for example, the solenoid valve V2 selects port NO. Note that, during the period W2, no exhaust is performed from the line L12.

[0086] After the period W2, as shown in the period W3, the solenoid valve V1 enters the connected state S3. As a result, the first adsorption unit 8A enters the adsorption process, and the second adsorption unit 8B enters the regeneration process. After the period W3, the period W2 is executed again.

[0087] In this way, the periods W1 and W3 are repeatedly executed via the period W2, and oxygen-enriched gas is produced in the adsorption step, while the adsorption function is restored in the regeneration step.

[0088] Furthermore, as shown in a period W4, the solenoid valve V3 is periodically turned on, and the draining tank 6 is drained of water.

[0089] Period W1 is divided into periods Wa, Wb, and We, and processing is performed to adjust the oxygen concentration. The same applies to period W3. That is, while solenoid valve V1 is in connected state S1 (or while solenoid valve V1 is in connected state S3), control is performed for periods Wa, Wb, and Wec. For example, period W1 is approximately 20 to 40 seconds, period Wa is approximately 0 to 10 seconds (or may be 0 seconds), period Wb is approximately 4 to 10 seconds, and period Wc is the time obtained by subtracting the total time of periods Wa and Wb from period W1 (period Wc = period W1 - period Wa - period Wb).

[0090] Period Wa is a first time period and is executed with the start of period W1. Specifically, during period Wa, solenoid valve V1 is in the connected state S1, and solenoid valve V2 selects port NO. As a result, solenoid valve V2 connects line L1 and line L2, and outside air is supplied to compressor 5. Then, compressor 5 supplies pressurized gas to second adsorption section 8B, which generates oxygen-enriched gas. The oxygen-enriched gas is sent to air chamber 12, and a portion of it is supplied to first adsorption section 8A. Then, exhaust gas discharged from the top of first adsorption section 8A is released into the atmosphere (discharged outside the system) via line L12. At this time, nitrogen, in particular, is discharged from first adsorption section 8A.

[0091] Then, during the transition to period Wb (second time), the solenoid valve V1 maintains its connected state S1, while the solenoid valve V2 selects port NC. As a result, the second adsorption unit 8B generates oxygen-enriched gas. The solenoid valve V2 connects the circulation line L10 to line L2, and the exhaust gas from the first adsorption unit 8A is actively drawn into the compressor 5 via the circulation line L10. The pressure in the first adsorption unit 8A and the circulation line L10 becomes lower than atmospheric pressure. This actively draws nitrogen and moisture from the first adsorption unit 8A. By actively drawing the exhaust gas from the first adsorption unit 8A, particularly by the compressor 5, dehumidification becomes possible. This dries the first adsorption unit 8A. The exhaust gas is not released into the atmosphere via line L12 but circulates to the compressor 5 via the circulation line L10. Note that outside air is replenished into the circulation line L10 via the bypass line L11.

[0092] Thus, during period W1, the control device 13 controls the solenoid valve V1 to start supplying pressurized gas to one of the adsorption sections (second adsorption section 8B), and during period Wa, controls the solenoid valve V2 to connect line L1 and line L2. Thereafter, during period W1 in which the control device 13 is supplying pressurized gas to one of the adsorption sections (second adsorption section 8B), the control device 13 controls the solenoid valve V2 to connect the circulation line L10 and line L2 for period Wb. In this way, the process transitions from period Wa to period Wb.

[0093] Then, when the period Wc begins, the solenoid valve V1 maintains the connected state S1, and the solenoid valve V2 selects port NO. As a result, the solenoid valve V2 connects the lines L1 and L2, and outside air is supplied to the compressor 5. The compressor 5 then supplies pressurized gas to the second adsorption unit 8B, which then generates oxygen-enriched gas. The oxygen-enriched gas is sent to the air chamber 12, and a portion of it is supplied to the first adsorption unit 8A. The exhaust gas discharged from the first adsorption unit 8A is then released into the atmosphere (discharged to the outside of the system) via line L12.

[0094] Here, the periods W1 and W3 start when the solenoid valve V1 switches to the connected state S1 or the connected state S3. Therefore, the exhaust gas discharged from the first adsorption unit 8A or the second adsorption unit 8B serving as the regeneration unit (the adsorption unit in the regeneration process) contains a large amount of nitrogen adsorbed in the previously executed adsorption process. Therefore, at the beginning of the periods W1 and W3, the exhaust gas contains a large amount of nitrogen (nitrogen-rich).

[0095] Furthermore, when period W1 or period W3 starts, oxygen-enriched gas is supplied to the first adsorption unit 8A or the second adsorption unit 8B as a regeneration unit via feedback line L9, and becomes exhaust gas. Therefore, as time passes after period W1 or period W3 starts, the exhaust gas becomes oxygen-rich.

[0096] In this way, during periods W1 and W3, the exhaust gas returned to compressor 5 initially contains a lot of nitrogen, and over time, it becomes rich in oxygen. By utilizing this characteristic, control device 13 can adjust the oxygen concentration of the oxygen-enriched gas.

[0097] Specifically, by shortening the ratio of the period Wa to the period W1 during which pressurized gas is supplied to one of the adsorption units in the control device 13 (by shortening the period Wa), more of the nitrogen-rich exhaust gas can be circulated to the compressor 5. Specifically, by reducing the ratio of the period Wa to the period W1, it is possible to prevent nitrogen-rich exhaust gas from being discharged to the system through the line L12, and to return more nitrogen-rich exhaust gas to the compressor 5 and circulate it within the system. This allows more nitrogen to be circulated within the system, thereby reducing the oxygen concentration of the oxygen-enriched gas generated. As described above, the shorter the ratio of the period Wa (first time) to the period during which pressurized gas is supplied to one of the adsorption units, the more the oxygen concentration of the oxygen-enriched gas generated can be reduced. Note that, as described above, during the period W1, the exhaust gas becomes oxygen-rich over time. Therefore, in order to reduce the oxygen concentration of the oxygen-enriched gas, it is also possible to reduce the ratio of the period Wb to the period W1 (by shortening the period Wb). Although the above description has been given using the period W1 as an example, the same applies to the period W3.

[0098] On the other hand, by increasing the ratio of the period Wb to the period W1 during which pressurized gas is supplied to one of the adsorption units in the control device 13 (by setting the period Wb longer), a larger amount of oxygen-rich exhaust gas can be circulated to the compressor 5. Specifically, the oxygen-enriched gas generated in the adsorption unit is supplied to the regeneration unit via the feedback line L9, and the oxygen-enriched gas is discharged from the regeneration unit as exhaust gas. Therefore, by increasing the ratio of the period Wb to the period W1, a larger amount of oxygen-rich exhaust gas based on the oxygen-enriched gas can be returned to the compressor 5 and circulated within the system. This allows a larger amount of oxygen to be circulated within the system, thereby increasing the oxygen concentration of the generated oxygen-enriched gas. In this way, the longer the ratio of the period Wb (second time) to the period during which pressurized gas is supplied to one of the adsorption units, the larger the oxygen concentration of the generated oxygen-enriched gas can be. Note that, as described above, since the exhaust gas contains a large amount of nitrogen immediately after the start of the period W1, it is preferable to appropriately set the period Wa within the period W1 (to be shorter) in order to increase the oxygen concentration of the oxygen-enriched gas. For example, it is preferable to set in advance a time (e.g., about 2 seconds) during which the nitrogen-rich exhaust gas is sufficiently discharged outside the system via line L12 immediately after period W1, and set period Wa to the time. By doing so, during period W1, the nitrogen-rich exhaust gas can be effectively discharged outside the system (period Wa), and the oxygen-rich exhaust gas can be effectively returned to compressor 5 (period Wb). In other words, it is possible to easily increase the oxygen concentration of the oxygen-enriched gas. Note that while the above description has been given using period W1 as an example, the same applies to period W3.

[0099] FIG. 6 is a graph showing an example of the relationship between the intake-side oxygen concentration and the discharge-side oxygen concentration. In FIG. 6, the horizontal axis represents the intake-side oxygen concentration (%) and the vertical axis represents the discharge-side oxygen concentration (%). The intake-side oxygen concentration is, for example, the oxygen concentration of the gas flowing upstream of the solenoid valve V1 (the drain tank 6), and the discharge-side oxygen concentration is the oxygen concentration of the gas discharged from the regulator 24. FIG. 6 shows an example of the relationship between the intake-side oxygen concentration and the discharge-side oxygen concentration when adjustment is made using the oxygen concentration adjustment function of the control device 13. Note that FIG. 6 shows an example where Tosoh SA-700 zeolite with a capacity of 1440 g is used in the first adsorption unit 8A (the same applies to the second adsorption unit 8B).

[0100] In FIG. 6, as an example, reference M1 indicates the case where oxygen-enriched gas is generated using gas with an oxygen concentration of approximately 21%, which is the oxygen concentration in the general atmosphere. By using the adjustment function of the control device 13 relative to reference M1, it is possible to lower the oxygen concentration on the intake side and the oxygen concentration on the discharge side, as shown in region R1. In other words, adjustment can be made to lower the oxygen concentration of the oxygen-enriched gas. The oxygen concentration is set depending on the purpose of use. The ability to adjust the oxygen concentration to lower it allows for use in applications where a low oxygen concentration is required.

[0101] Furthermore, by using the adjustment function of the control device 13 relative to the reference M1, it is possible to increase the oxygen concentration on the intake side and increase the oxygen concentration on the discharge side, as shown in region R2. That is, adjustment is possible in the direction of increasing the oxygen concentration of the oxygen-enriched gas. The ability to adjust in the direction of increasing the oxygen concentration makes it possible to use in applications requiring a high oxygen concentration.

[0102] In this way, when the exhaust gas flowing through the circulation line L10 changes from a nitrogen-rich state to an oxygen-rich state, the oxygen concentrator 1 has an oxygen concentration adjustment function to decrease the oxygen concentration of the oxygen-enriched gas by increasing the amount of nitrogen-rich exhaust gas supplied to the compressor 5. The oxygen concentrator 1 also has an oxygen concentration adjustment function to increase the oxygen concentration of the oxygen-enriched gas by increasing the amount of oxygen-rich exhaust gas supplied to the compressor 5. The oxygen concentration can be adjusted, for example, by the control device 13. The adjustment is performed by the control device 13 controlling the solenoid valve V2. Oxygen-rich refers to a state in which there is more oxygen (a state with a high oxygen concentration) than outside air (outside air taken in through line L1, which is ordinary air), and nitrogen-rich refers to a state in which there is more nitrogen (a state with a high nitrogen concentration) than outside air (outside air taken in through line L1, which is ordinary air).

[0103] FIG. 7 is a diagram showing a modified example of the overall configuration of the oxygen concentrator 1 shown in FIG. 5. As shown in FIG. 5, an orifice OR4 is provided on the secondary side of the check valve 21 in the discharge line L12. One end of the line L12 is connected to the circulation line L10, and the line L12 discharges the gas in the circulation line L10 to the outside of the system via the check valve 21. The provision of the orifice OR4 limits the flow rate of the exhaust gas discharged from the line L12. When adjusting to lower the oxygen concentration, the provision of the orifice OR4 suppresses gas discharge from the line L12, effectively circulating the nitrogen-rich exhaust gas to the compressor 5. This enables effective adjustment to lower the oxygen concentration of the oxygen-enriched gas. As shown in FIG. 7, both the silencer 20 and the orifice OR4 may be provided in the line L12, or only one of them may be provided. The provision of the silencer 20 reduces the exhaust noise after the orifice OR4.

[0104] On the other hand, when adjusting to increase the oxygen concentration, the exhaust gas containing a large amount of nitrogen can be effectively released (in large quantities) from the line L12 by making the silencer 20 and the orifice OR4 larger in diameter. Therefore, the exhaust gas containing a large amount of oxygen can be effectively circulated to the compressor 5.

[0105] Furthermore, in this embodiment, as in the first embodiment, a bypass line L11 having an orifice OR3 and a check valve 22 is provided. However, it is possible to appropriately supply outside air to the compressor 5 by balancing the periods Wa, Wb, and Wc. Therefore, depending on the required gas volume, the bypass line L11 (including the orifice OR3 and the check valve 22) may be omitted, as shown in FIG. 7 . Also, while the oxygen-enriched gas discharged in the adsorption process is supplied to the regeneration process via the feedback line L9, the supply of oxygen-enriched gas to the regeneration process is not limited to the feedback line L9. That is, using the feedback line L9 as an example, the part that supplies oxygen-enriched gas to the adsorption section in the regeneration process and purges nitrogen and moisture from the adsorption section can be used as the purge section. For example, the purge section may be a section (line) that supplies oxygen-enriched gas from the air chamber 12 to the adsorption section in the regeneration process. Note that the purge section is not limited as long as it can supply oxygen-enriched gas to the adsorption section in the regeneration process and purge nitrogen and moisture from the adsorption section.

[0106] <Action and effect> As described above, in this embodiment, the control device 13 has the function of adjusting between a first state in which the first line (line L1) and the second line (line L2) are connected by the intake solenoid valve (solenoid valve V2) and a second state in which the circulation line L10 and the second line (line L2) are connected by the intake solenoid valve (solenoid valve V2), thereby enabling adjustment of the oxygen concentration of the oxygen-enriched gas generated in the adsorption section.

[0107] According to this configuration, the oxygen concentration of the generated oxygen-enriched gas can be adjusted by adjusting the first state and the second state. For example, the oxygen concentration can be adjusted to decrease or increase. That is, the oxygen concentration can be adjusted to suit the application of the oxygen-enriched gas. Therefore, the oxygen concentration of the oxygen-enriched gas can be stabilized, and the productivity of the oxygen-enriched gas produced by the oxygen concentrator 1 can be improved.

[0108] In addition, in this embodiment, the control device 13 is capable of adjusting the time for executing the first state and the time for executing the second state.

[0109] According to this configuration, the oxygen concentration can be adjusted by adjusting each state.

[0110] In addition, in this embodiment, the control device 13 controls the solenoid valve V1 to start supplying pressurized gas to one of the adsorption sections, and controls the intake solenoid valve (solenoid valve V2) to connect the first line (line L1) and the second line (line L2) for a first time, and then, while supplying pressurized gas to one of the adsorption sections, controls the intake solenoid valve (solenoid valve V2) to connect the circulation line L10 and the second line (line L2) for a second time.

[0111] According to this configuration, it is possible to adjust the oxygen concentration to decrease or increase.

[0112] Furthermore, in this embodiment, the shorter the ratio of the first time (period Wa) to the period (W1 or W3) during which pressurized gas is supplied to one of the adsorption units, the lower the oxygen concentration of the oxygen-enriched gas generated, and the longer the ratio of the second time (period Wb) to the period (W1 or W3) during which pressurized gas is supplied to one of the adsorption units, the higher the oxygen concentration of the oxygen-enriched gas generated.

[0113] According to this configuration, the oxygen concentration can be increased or decreased by adjusting the first time period and the second time period.

[0114] In addition, in this embodiment, the system further includes a discharge line (line L12) whose one end is connected to the circulation line L10 and which discharges the gas in the circulation line L10 to the outside of the system via a check valve 21, and an orifice OR4 provided in the discharge line (line L12) which limits the flow rate of the gas being discharged.

[0115] According to this configuration, the orifice OR4 makes it easier to adjust the oxygen concentration in the decreasing direction.

[0116] In this embodiment, the system includes a first line (line L1), a compressor 5 that takes in outside air through the first line and pressurizes it, a switching valve (solenoid valve V1) that switches between an adsorption process in which the pressurized gas output from the compressor 5 is supplied to an adsorption section (first adsorption section 8A or second adsorption section 8B) and adsorbs nitrogen and moisture in the adsorption section to discharge oxygen-enriched gas, and a regeneration process in which the adsorbed nitrogen and moisture are discharged from the adsorption section, a purge section (feedback line L9) that supplies the oxygen-enriched gas discharged in the adsorption process to the adsorption section in the regeneration process and purges nitrogen and moisture from the adsorption section, and a purge section (feedback line L9) that purges the exhaust gas discharged from the adsorption section in the regeneration process. The compressor 5 is also provided with a circulation line L10 that supplies the exhaust gas to the intake side of the compressor 5. When the exhaust gas flowing through the circulation line L10 changes from a nitrogen-rich state (a state with more nitrogen than the outside air) to an oxygen-rich state (a state with more oxygen than the outside air), the exhaust gas supplied to the compressor 5 is made nitrogen-rich (by increasing the amount of exhaust gas in the nitrogen-rich state) to reduce the oxygen concentration of the oxygen-enriched gas, and the exhaust gas supplied to the compressor 5 is made oxygen-rich (by increasing the amount of exhaust gas in the oxygen-rich state) to increase the oxygen concentration of the oxygen-enriched gas.

[0117] This configuration makes it possible to adjust the oxygen concentration of the generated oxygen-enriched gas. For example, the oxygen concentration can be adjusted to decrease or increase. That is, the oxygen concentration can be adjusted to suit the intended use of the oxygen-enriched gas. For example, when the generated oxygen-enriched gas is used for oxygen inhalation into the human body in the medical field, excessively high oxygen concentrations must be avoided, so it is necessary to adjust the concentration to the desired oxygen concentration (for example, to lower the oxygen concentration so as not to exceed the upper limit). Furthermore, when it is difficult to obtain the desired oxygen concentration due to deterioration of the adsorbent over time and the oxygen concentration is prone to decrease, it is also possible to adjust the concentration to increase it to the desired oxygen concentration. In other words, it is possible to extend the life of the device.

[0118] Furthermore, since the exhaust gas discharged from the regeneration unit can be sucked in by the compressor 5, shortening of the lifespan of the adsorption device 8 can be suppressed, and frequent replacement of the first adsorption unit 8A and the second adsorption unit 8B can be suppressed. Furthermore, since the oxygen-enriched gas can be produced in the adsorption process using the first adsorption unit 8A and the second adsorption unit 8B while the recovery process is performed, the oxygen-enriched gas can be produced stably. Furthermore, by adjusting the oxygen concentration, it is possible to stably produce oxygen-enriched gas with a desired oxygen concentration. In other words, it is possible to improve the productivity of oxygen-enriched gas.

[0119] In this embodiment, the desired oxygen concentration is obtained by adjusting the timing and length of the connection period while controlling solenoid valves V1 and V2 to switch between the first state and the second state, but it is also possible to change the line connection mode. For example, solenoid valve V2 (switching valve) can be eliminated, and the first line (line L1) can be provided as an intake line connected to the intake side of compressor 5, with circulation line L10 connected midway through this intake line, or a configuration can be configured in which both the intake line and circulation line L10 are connected to the intake side of compressor 5. In this configuration, the state of the main part of the circulating gas from circulation line L10 changes sequentially from moisture (water vapor) to nitrogen to purged oxygen, and the oxygen concentration can be adjusted by appropriately switching solenoid valve V1 (switching valve). In adjusting the oxygen concentration to a lower level so as not to exceed a predetermined upper limit in the range of use of high-concentration oxygen in the medical field and the like, during the period when the circulating gas is converted to nitrogen, the control device 13 controls the solenoid valve V1 to connect line L4 or line L5 from the adsorption unit in the regeneration process to the circulation line L10, so that the nitrogen is mixed with the outside air on line L1 and supplied to the compressor 5. This reduces the amount of oxygen in the gas supplied to the compressor 5, making it possible to lower the oxygen concentration. In this way, the control device 13 has the function of lowering the oxygen concentration by controlling the supply to the compressor 5 when the circulating gas (exhaust gas) discharged from the adsorption unit in the regeneration process has a higher nitrogen content than the outside air (nitrogen-rich state). Furthermore, in order to adjust the oxygen concentration to a higher level in order to prevent a decrease in the oxygen output concentration due to deterioration of the adsorbent over time, etc., during the period in which the circulating gas changes to purged oxygen, the controller 13 similarly controls the connection of the solenoid valve V1, so that the purged oxygen is mixed with the outside air in line L1 and supplied to the compressor 5. At this time, the controller 13 has the function of increasing the oxygen concentration by controlling the supply to the compressor 5 when the circulating gas (discharge gas) discharged from the adsorption section in the regeneration process has a higher oxygen content than the outside air (oxygen-rich state). Depending on the specifications and applications of the oxygen concentrator 1, the device may simply reduce the oxygen concentration so that it does not exceed a predetermined concentration (upper limit), or conversely, may simply increase the oxygen concentration so that it does not fall below a predetermined concentration (lower limit), or may combine both functions to adjust the concentration. Predetermined values indicating the upper and lower limits of the oxygen concentration may be stored in the memory unit 32 within the control device 13, and an oxygen concentration sensor that detects the oxygen concentration may be provided on the output side of the oxygen-enriched gas. Feedback control may be performed so that the control device 13 appropriately adjusts the oxygen concentration based on the sensor detection results. In this case, the control device 13 can automatically adjust the oxygen concentration. In addition, in this embodiment, two adsorption sections, the first adsorption section 8A and the second adsorption section 8B, are provided and oxygen concentration is performed continuously under swing control, but it is also possible to use one adsorption section and adjust the increase or decrease of the oxygen concentration.

[0120] <<Variations>> The present invention is not limited to the above-described embodiments. In other words, designs that are produced by those skilled in the art with appropriate design modifications to the above-described specific examples are also included within the scope of the present invention as long as they include the features of the present invention. Furthermore, the elements of the above-described embodiments and the following modifications can be combined to the extent technically possible, and such combinations are also included within the scope of the present invention as long as they include the features of the present invention.

[0121] For example, in the first and second embodiments, a case where a relief type is used as the regulator 24 has been described as an example, but the specifications of the regulator 24 are not limited, and for example, a non-relief type may be used.

[0122] Furthermore, in the first embodiment, a case has been described as an example in which the solenoid valve V2 is switched from a state in which the line L2 and the circulation line L10 are connected to a state in which the line L2 and the line L1 are connected during the period in which the pressurized gas is being supplied. However, control may be performed to switch from a state in which the line L2 and the line L1 are connected to a state in which the line L2 and the circulation line L10 are connected during this period. That is, the solenoid valve V2 may select port NO during period T2 within period T1, and may select port NC during period T3 within period T1.

[0123] Furthermore, in the first and second embodiments, check valves are provided at various locations as an example, but solenoid valves may be provided instead of the check valves.

[0124] Furthermore, in the first and second embodiments, the orifice diameter of orifice OR2 is described as being larger than (or equal to) the orifice diameter of orifice OR1, but the relationship between the orifice diameters is not limited to the above, depending on factors such as the balance with the amount of oxygen-enriched gas supplied to the air chamber 12.

[0125] Furthermore, in the first embodiment, while the solenoid valve V1 is in the connected state S1 or the connected state S3, the solenoid valve V2 connects the line L1 to the line L2 or the circulation line L10 to the line L2, thereby allowing the compressor 5 to take in the exhaust gas from the first adsorption unit 8A or the second adsorption unit 8B and the outside air, but the periods T1, T2, T3, etc. of the solenoid valves V1 and V2 may be variably controlled to change the balance between the intake amounts of the exhaust gas and the outside air, thereby varying the amount of oxygen in the intake air of the compressor 5 and increasing or decreasing the oxygen concentration of the oxygen-enriched gas in the oxygen concentrator 1. Furthermore, to adjust the oxygen concentration, the start timing of the period T1 or the period T2 may be shifted so that the period starts from a state in which the solenoid valve V2 selects port NO.

[0126] Furthermore, in the second embodiment, a case has been described as an example in which the time for each operation can be adjusted by the user as an oxygen concentration adjustment function in the control device 13. However, the control device 13 may automatically set the time for each operation based on a target oxygen concentration and execute the operation.

[0127] In the second embodiment, the case where the time of the first state and the time of the second state are adjusted to adjust the balance between the first state and the second state has been described as an example, but the present invention is not limited to adjusting the time. For example, if the opening degree of the solenoid valve V2 or the like is controllable, the opening degree for circulating gas in the first state and the opening degree for circulating gas in the second state may be adjusted. In other words, the specific adjustment method is not limited as long as it is possible to adjust the balance between the amount of outside air supplied to the compressor 5 via the line L1 in the first state and the amount of exhaust air supplied to the compressor 5 via the circulation line L10 in the second state.

[0128] In the first and second embodiments, the orifice OR2 is described as being provided between the confluence (confluence point) of the lines L6 and L7 and the air chamber 12. However, this is not limited to the above. For example, the orifice OR2 may be provided between the check valve 17A and the confluence point, and between the check valve 17B and the confluence point. [Explanation of symbols]

[0129] 1: Oxygen concentrator 5: Compressor 8: Adsorption device 8A: First suction part 8B:Second suction part L9: Feedback line L10: Circulation line 13: Control device L1: Line (first line) V1: Solenoid valve

Claims

1. The first line and a compressor that draws in gas through the first line and pressurizes it; a solenoid valve to which the pressurized gas output from the compressor is supplied and which switches the supply destination of the pressurized gas; a first adsorption unit to which the pressurized gas is supplied from one end side by the electromagnetic valve and which adsorbs nitrogen and moisture from the pressurized gas; a second adsorption section to which the pressurized gas is supplied from one end side by the electromagnetic valve and which adsorbs nitrogen and moisture from the pressurized gas; a feedback line connecting the other end of the first adsorption unit and the other end of the second adsorption unit; a control device that controls the electromagnetic valve to supply the pressurized gas to one of the first adsorption unit and the second adsorption unit, and supplies the oxygen-enriched gas discharged from the adsorption unit to the other of the first adsorption unit and the second adsorption unit via the feedback line; a circulation line that supplies the exhaust gas discharged from the other side to the intake side of the compressor; An oxygen concentrator comprising:

2. an intake solenoid valve connecting a second line connected to an intake port of the compressor to either the first line or the circulation line; The oxygen concentrator of claim 1 further comprising:

3. a bypass line connecting the first line and the circulation line; a check valve provided in the bypass line, the check valve having a primary side on the first line side and a secondary side on the circulation line side; The oxygen concentrator of claim 2 further comprising:

4. an orifice provided in the bypass line to limit the flow rate from the primary side to the secondary side; The oxygen concentrator of claim 3 further comprising:

5. The control device during a period in which the pressurized gas is being supplied to the one adsorption unit, the intake solenoid valve is controlled to switch from a state in which the second line and the circulation line are connected to a state in which the second line and the first line are connected; 5. The oxygen concentrator according to claim 2.

6. The first line takes in gas through an activated carbon filter.

5. The oxygen concentrator according to claim 1.

7. a drain tank provided in the middle of a third line connecting the compressor and the solenoid valve, for draining water from the pressurized gas; The oxygen concentrator according to claim 1 , further comprising:

8. the control device has a function of adjusting between a first state in which the first line and the second line are connected by the intake solenoid valve and a second state in which the circulation line and the second line are connected by the intake solenoid valve, thereby making it possible to adjust the oxygen concentration of the oxygen-enriched gas generated in the adsorption unit.

5. The oxygen concentrator according to claim 2.

9. the control device is capable of adjusting a time for executing the first state and a time for executing the second state; 9. The oxygen concentrator of claim 8.

10. the control device controls the electromagnetic valve to start supplying the pressurized gas to the one of the adsorption units, and controls the intake electromagnetic valve to connect the first line and the second line for a first time, and then, while the pressurized gas is being supplied to the one of the adsorption units, controls the intake electromagnetic valve to connect the circulation line and the second line for a second time.

10. The oxygen concentrator of claim 9.

11. the shorter the ratio of the first time period to the period during which the pressurized gas is supplied to the one of the adsorption units, the more the oxygen concentration of the generated oxygen-enriched gas can be reduced, The longer the ratio of the second time to the period, the more the oxygen concentration of the generated oxygen-enriched gas can be increased.

11. The oxygen concentrator of claim 10.

12. a discharge line connected at one end to the circulation line and configured to discharge the gas in the circulation line to the outside of the system via a check valve; an orifice in the discharge line that limits the flow rate of the discharged gas; The oxygen concentrator of claim 8 further comprising:

13. The first line and a compressor that draws in outside air through the first line and pressurizes it; a switching valve that switches between an adsorption process in which the pressurized gas output from the compressor is supplied to an adsorption unit, and nitrogen and moisture are adsorbed in the adsorption unit to discharge an oxygen-enriched gas, and a regeneration process in which the adsorbed nitrogen and moisture are discharged from the adsorption unit; a purge unit that supplies the oxygen-enriched gas discharged in the adsorption step to the adsorption unit in the regeneration step and purges nitrogen and moisture from the adsorption unit; a circulation line that supplies exhaust gas discharged from the adsorption unit in the regeneration step to the intake side of the compressor; Equipped with When the exhaust gas flowing through the circulation line changes from a state in which there is more nitrogen than the outside air to a state in which there is more oxygen than the outside air, the oxygen concentration of the oxygen-enriched gas is reduced by making the exhaust gas supplied to the compressor in a state in which there is more nitrogen than the outside air, and the oxygen concentration of the oxygen-enriched gas is increased by making the exhaust gas supplied to the compressor in a state in which there is more oxygen than the outside air.

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