JP2014000241A - Oxygen concentrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem that when the flow rate of concentrated oxygen gas taken from a take-out port is low, the flow rate becomes unstable.SOLUTION: In the oxygen concentrator of the present invention, control is carried out differently depending on whether the flow rate of concentrated oxygen gas taken from a take-out port is greater than or not greater than a predetermined value. When the flow rate of the concentrated oxygen gas from the take-out port is not greater than the predetermined value, processes for pressure equalization, simultaneous pressurization, pressurization/depressurization, oxygen supply, and purge are carried out before the adsorption cylinder from which the concentrated oxygen gas is supplied to an oxygen tank is switched from a first adsorption cylinder to a second adsorption cylinder.

Description

  The present invention relates to an oxygen concentrator for supplying oxygen-enriched gas to the outside.

  The oxygen concentrator includes a compressor that compresses air sucked from the outside, and a first adsorption cylinder and a second adsorption cylinder that are supplied with compressed air from the compressor and store an adsorbent that adsorbs nitrogen in the compressed air. I have. In this oxygen concentrator, the air compressed by the compressor is alternately supplied to the first adsorption cylinder and the second adsorption cylinder, and the oxygen enriched gas is supplied from the first adsorption cylinder and the second adsorption cylinder to the oxygen tank. The oxygen-enriched gas supplied to the oxygen tank is taken out from the take-out port. Here, for example, while the air compressed by the compressor is supplied to the first adsorption cylinder (while the first adsorption cylinder is pressurized), the pressure is reduced by opening the second adsorption cylinder to the atmosphere. The When the oxygen-enriched gas is supplied from the first adsorption cylinder to the oxygen tank, the air compressed by the compressor is supplied to the second adsorption cylinder, and the pressure is reduced by opening the first adsorption cylinder to the atmosphere. . Therefore, in this PSA (Pressure Swing Adsorption System) oxygen concentrator, the pressure in the first adsorption cylinder and the second adsorption cylinder fluctuates in a pressure range higher than atmospheric pressure.

  Incidentally, it is known that the adsorption efficiency of the adsorbent is high when the pressure is low and decreases when the pressure is high. Therefore, when the pressures of the first adsorption cylinder and the second adsorption cylinder fluctuate in a pressure range higher than the atmospheric pressure as in the PSA oxygen concentrator described above, there is a problem that the adsorption efficiency is low.

  Therefore, as in the above PSA oxygen concentrator, the adsorption cylinder is not opened to the atmosphere after the oxygen concentrated gas is supplied to the oxygen tank and depressurized, but the adsorption cylinder is supplied after the oxygen concentrated gas is supplied to the oxygen tank. There is a VPSA (Vacuum Pressure Swing Adsorption System) oxygen concentrator that sucks and depressurizes with a vacuum pump. In this VPSA oxygen concentrator, the pressure in the first adsorption cylinder and the second adsorption cylinder fluctuates in a pressure range between a pressure higher than atmospheric pressure and a pressure lower than atmospheric pressure, so that the adsorption efficiency of the adsorbent is improved. .

JP 2008-137853 A

  Here, in the VPSA oxygen concentrator, the pressure in the oxygen tank tends to be low because the pressure of the oxygen-concentrated gas taken out from the adsorption cylinder is lower than that in the PSA oxygen concentrator. As an example of the pressure change in the adsorption cylinder, the pressure for taking out the oxygen-enriched gas from the adsorption cylinder to the oxygen tank in the PSA oxygen concentrator in FIG. The pressure in the cylinder is about 140 kPa, whereas the pressure for extracting the oxygen-enriched gas from the adsorption cylinder in the VPSA oxygen concentrator in FIG. 4B is about 60 kPa. And when operating with a reduced flow rate of oxygen enriched gas from the outlet of the oxygen concentrator, in order to reduce power consumption, the operating capacity of the compressor, etc. may be lowered. Oxygen-enriched gas extraction pressure (oxygen tank pressure) is further reduced, so that the pressure of the pressure reducing valve required to set the correct flow rate with the flow regulator and the oxygen-enriched gas flow stably in the piping Since the required pressure cannot be satisfied, there is a problem that the flow rate of the oxygen-enriched gas cannot be stably supplied from the outlet of the oxygen concentrator.

  Therefore, an object of the present invention is to provide an oxygen concentrator that can prevent the flow rate of the oxygen-concentrated gas taken out from the outlet from becoming unstable.

  An oxygen concentrator according to a first aspect of the present invention has an adsorbent that selectively adsorbs nitrogen from air, and each of the two adsorption containers for supplying oxygen enriched gas to an oxygen tank, and each of the two adsorption containers, A control valve that switches between a pressurized state in which air compressed by a compressor is supplied and a reduced pressure state in which the pressure is reduced by a vacuum pump; and an outlet for taking out the oxygen-enriched gas to the outside. When the flow rate of the oxygen-enriched gas is equal to or lower than the predetermined flow rate, the state is switched from the state in which the oxygen-enriched gas is supplied from one adsorption vessel to the oxygen tank to the state in which the oxygen-enriched gas is supplied from the other adsorption vessel to the oxygen tank. In the meantime, the control valve is controlled so that the two adsorption containers are simultaneously pressurized.

  In this oxygen concentrator, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than a predetermined flow rate, the oxygen-enriched gas is supplied from one adsorption vessel to the oxygen tank, and then from the other adsorption vessel to the oxygen tank. Since the two adsorption vessels are simultaneously pressurized before switching to the state in which the oxygen-enriched gas is supplied, the average pressure in the adsorption vessel rises, so that the oxygen-enriched gas is taken out from the adsorption vessel. The pressure also rises and the oxygen pressure in the oxygen tank increases. Therefore, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than the predetermined flow rate, it is possible to prevent the flow rate of the oxygen-enriched gas from becoming unstable.

  In conventional oxygen concentrators, adsorbents that are easily adsorbed in the order of nitrogen, oxygen, and argon gas contained in the air may be used, but the performance of the adsorbent is excessive compared to the amount of oxygen-enriched gas to be extracted. In this case, since the adsorbent adsorbs not only nitrogen but also oxygen, it is known that the oxygen-concentrated gas to be taken out contains a large amount of argon gas, and the oxygen concentration is lowered. On the other hand, in this oxygen concentrator, when the flow rate of the oxygen-enriched gas taken out from the outlet is below a predetermined flow rate, the pressures of the first adsorption vessel and the second adsorption vessel are higher than those of the conventional VPSA oxygen concentrator. Since it varies depending on the range, the adsorption efficiency of the adsorbent decreases. Therefore, in this oxygen concentrator, when the flow rate of the oxygen-enriched gas taken out from the outlet is small, it is possible to prevent the adsorbent adsorbing power in the first adsorption vessel and the second adsorption vessel from being excessive. High concentration oxygen-enriched gas can be taken out. Therefore, in this oxygen concentrator, by changing the pressure range of the first adsorption container and the second adsorption container and changing the adsorption efficiency of the adsorbent, the flow rate of the oxygen enriched gas taken out from the outlet is small. In some cases, a high concentration oxygen enriched gas can be removed.

  An oxygen concentrator according to a second aspect of the present invention is the oxygen concentrator according to the first aspect of the present invention, wherein when the flow rate of the oxygen concentrated gas taken out from the outlet is a predetermined flow rate or less, the two adsorption containers are simultaneously The simultaneous pressurization time or the rotation speed of the compressor at the time of the pressurization state is changed according to the oxygen flow rate.

  In this oxygen concentrator, the simultaneous pressurization time during which the two adsorption containers are pressurized simultaneously or the rotational speed of the compressor is changed depending on the flow rate of the oxygen-concentrated gas taken out from the outlet, so that the power consumption can be reduced. Can do. Moreover, since the simultaneous pressurization time or the rotation speed of the compressor is adjusted according to the flow rate of the oxygen-enriched gas taken out from the outlet, the oxygen-enriched gas having a high oxygen concentration can be taken out stably.

  As described above, according to the present invention, the following effects can be obtained.

  In the first invention, when the flow rate of the oxygen-enriched gas taken out from the outlet is a small flow rate, it is possible to prevent the flow rate of the oxygen-enriched gas from becoming unstable. Further, when the flow rate of the oxygen-enriched gas taken out from the take-out port is a small flow rate, a high-concentration oxygen-enriched gas can be taken out.

  In the second invention, the power consumption can be reduced regardless of the flow rate of the oxygen-enriched gas taken out from the outlet. Moreover, the oxygen-enriched gas having a high concentration can be taken out stably.

It is a block diagram of the oxygen concentrator of the embodiment of the present invention. It is a process table | surface which shows the operation | movement at the time of large flow control. It is a figure which shows the pressure change of the 1st adsorption cylinder and the 2nd adsorption cylinder at the time of large flow control. It is a process table | surface which shows the operation | movement at the time of small flow control. It is a figure which shows the pressure change of the 1st adsorption cylinder and the 2nd adsorption cylinder at the time of small flow control. FIG. 4A is a diagram showing a pressure change in the adsorption cylinder in the PSA oxygen concentrator, and FIG. 4B is a diagram showing a pressure change in the adsorption cylinder in the VPSA oxygen concentrator.

<First Embodiment>
Hereinafter, a first embodiment of the present invention will be described with reference to FIG. FIG. 1 is a block diagram of an oxygen concentrator according to a first embodiment of the present invention.

  The oxygen concentrator 1 of this embodiment is used in home oxygen therapy that provides oxygen-enriched gas to respiratory disease patients and the like. As shown in FIG. 1, the oxygen concentrator 1 includes a compressor 2 that compresses air sucked in from the outside, and a compressed air supplied from the compressor 2 and an adsorbent that adsorbs nitrogen in the compressed air. It has the 1st adsorption cylinder 5a and the 2nd adsorption cylinder 5b, and the vacuum pump 4 which attracts | sucks the air inside the 1st adsorption cylinder 5a and the 2nd adsorption cylinder 5b.

  Control valves 3a and 3b connected to the first adsorption cylinder 5a and the second adsorption cylinder 5b and connected to the vacuum pump 4 are respectively connected to the gas flow path on the compressed air discharge side of the compressor 2. It is arranged. The control valve 3a is a three-port valve, and is a pressurized state in which compressed air discharged from the compressor 2 is supplied to the first adsorption cylinder 5a, and a reduced pressure in which air is sucked from the first adsorption cylinder 5a by the vacuum pump 4. Switch between states. Further, the control valve 3b is a three-port valve, and is in a pressurized state in which compressed air discharged from the compressor 2 is supplied to the second adsorption cylinder 5b, and the vacuum pump 4 sucks air from the second adsorption cylinder 5b. Switch to the decompressed state.

  A check valve 6a is disposed in the gas flow path on the downstream side of the first adsorption cylinder 5a, and a check valve 6b is disposed in the gas flow path on the downstream side of the second adsorption cylinder 5b. Yes. The check valves 6a and 6b are configured such that the oxygen-enriched gas discharged from the first adsorption cylinder 5a and the second adsorption cylinder 5b flows only downstream. A purge valve 7 is disposed in a flow path connecting the gas flow path between the first adsorption cylinder 5a and the check valve 6a and the gas flow path between the second adsorption cylinder 5b and the check valve 6b. It is installed.

  The oxygen-enriched gas from the check valve 6a and the oxygen-enriched gas from the check valve 6b are supplied to the oxygen tank 9 via the product valve 8, and the oxygen-enriched gas is stored in the oxygen tank 9. . On the downstream side of the oxygen tank 9, a pressure reducing valve 10 for reducing the pressure of the oxygen-enriched gas from the oxygen tank 9, a flow rate regulator 11 for adjusting the flow rate of the oxygen-enriched gas, and an outlet for taking out the oxygen-enriched gas to the outside 12 are arranged. A cannula is connected to the outlet 12.

  The oxygen concentrator 1 also has a pressure sensor 18 that detects the pressure in the oxygen tank 9 and a control unit 20 that controls the operating state of the oxygen concentrator 1. The pressure sensor 18 is for measuring the pressure in the oxygen tank 9 to grasp the operating condition or detecting an abnormal state in which the pressure in the oxygen tank 9 has become very high. The control unit 20 controls the compressor 2, the control valves 3 a and 3 b, the vacuum pump 4, the purge valve 7 and the product valve 8.

  The control unit 20 performs different control depending on whether the flow rate of the oxygen-enriched gas taken out from the outlet 12 is greater than a predetermined amount or less than a predetermined amount. The oxygen concentrator 1 of the present embodiment can increase the flow rate of the oxygen-enriched gas taken out from the outlet 12 up to 5 liters per minute and adjust the flow rate regulator 11 to adjust the oxygen flow rate. It can be adjusted to a plurality of flow rates of 5 liters per minute or less. For example, the control unit 20 performs a large flow rate control when the flow rate adjusted by the flow rate regulator 11 is greater than 2 liters per minute, and performs a small flow rate control when the flow rate is 2 liters per minute or less.

  The operation at the time of large flow control and the operation at the time of small flow control of the oxygen concentrator 1 will be described. Fig.2 (a) is a process table | surface which shows 1/2 cycle among operation | movement at the time of large flow control. In the remaining 1/2 cycle, the operations of the purge valve and the product valve are the same except that the states of the first adsorption cylinder 5a and the second adsorption cylinder 5b are reversed. FIG. 2B is a diagram illustrating changes in pressure in the first adsorption cylinder and the second adsorption cylinder during large flow rate control. Fig.3 (a) is a process table | surface which shows 1/2 cycle among operation | movement at the time of small flow control. In the remaining 1/2 cycle, the operations of the purge valve and the product valve are the same except that the states of the first adsorption cylinder 5a and the second adsorption cylinder 5b are reversed. FIG. 3B is a diagram illustrating changes in pressure in the first adsorption cylinder and the second adsorption cylinder during the small flow rate control.

  Here, the operation after the oxygen enriched gas is supplied from the first adsorption cylinder 5a to the oxygen tank 9 until the oxygen enriched gas is supplied from the second adsorption cylinder 5b to the oxygen tank 9 will be described. The operation from when the oxygen-enriched gas is supplied from the cylinder 5b to the oxygen tank 9 until the oxygen-enriched gas is supplied from the first adsorption cylinder 5a to the oxygen tank 9 is the same.

(Operation during large flow control)
At the time of large flow control, as shown in FIG. 2A, the pressure equalization process, the pressurization / decompression process, the oxygen supply process, and the purge process are performed on the first adsorption cylinder 5a and the second adsorption cylinder 5b. Is called.

<Pressure equalization process>
In the oxygen supply step, the first adsorption cylinder 5a and the compressor 2 are connected by the control valve 3a, the second adsorption cylinder 5b and the vacuum pump 4 are connected by the control valve 3b, and the purge valve 7 and the product valve 8 are Also, the product valve 8 is switched to the closed state from the step of supplying the oxygen enriched gas from the first adsorption cylinder 5a to the oxygen tank 9, and the second adsorption cylinder 5b and the compressor 2 are connected by the control valve 3b. Then, go to the pressure equalization process. At this time, the air compressed by the compressor 2 is supplied to the first adsorption cylinder 5a and the second adsorption cylinder 5b, and the purge valve 7 is open, so that the air in the first adsorption cylinder 5a passes through the purge valve 7. To the second suction cylinder 5b. Furthermore, the air in the first adsorption cylinder 5a also moves to the second adsorption cylinder 5b via the control valve 3a and the control valve 3b. Therefore, in the pressure equalizing step, the first adsorption cylinder 5a is depressurized, the second adsorption cylinder 5b is pressurized, and the first adsorption cylinder 5a and the second adsorption cylinder 5b are at substantially equal pressure.

<Pressure reduction process>
Then, in the pressure equalizing step, when the pressure of the first adsorption cylinder 5a and the pressure of the second adsorption cylinder 5b become substantially the same, the control valve 3a is switched so as to connect the first adsorption cylinder 5a and the vacuum pump 4. At the same time, the purge valve 7 is switched to the closed state, and the process proceeds to the pressurizing and depressurizing step (the product valve is closed). At this time, since the second adsorption cylinder 5b and the compressor 2 are connected by the control valve 3b, the air compressed by the compressor 2 is supplied to the second adsorption cylinder 5b. Further, since the first adsorption cylinder 5a and the vacuum pump 4 are connected by the control valve 3a, the air in the first adsorption cylinder 5a is sucked into the vacuum pump 4. Therefore, in this pressurization and depressurization step, the first adsorption cylinder 5a is depressurized and the second adsorption cylinder 5b is pressurized.

<Oxygen supply process>
Then, when a predetermined time elapses in the pressurizing and depressurizing process, the product valve 8 is switched to open, and the process proceeds to the oxygen supplying process. At this time, the oxygen-enriched gas in the second adsorption cylinder 5 b moves to the oxygen tank 9 via the product valve 8. Therefore, in the oxygen supply process, the pressure of the second adsorption cylinder 5b decreases, but the rate of increase of the pressure of the first adsorption cylinder 5a decreases.

<Purge process>
Then, when a predetermined time has elapsed in the oxygen supply process, the purge valve 7 is switched to open, and the process proceeds to the purge process. At this time, the air in the second adsorption cylinder 5b moves to the first adsorption cylinder 5a via the purge valve 7. Thereby, the air of the 1st adsorption cylinder 5a can be efficiently sucked by the vacuum pump 4. Therefore, in the purge process, the pressure in the first adsorption cylinder 5a and the pressure in the second adsorption cylinder 5b do not change much.

(Operation during small flow control)
On the other hand, at the time of the small flow rate control, as shown in FIG. 3A, the pressure equalizing process, the simultaneous pressurizing process, the pressurizing / depressurizing process, and the oxygen supply are performed for the first adsorption cylinder 5a and the second adsorption cylinder 5b. A process and a purge process are performed.

<Pressure equalization process>
In the oxygen supply step, the first adsorption cylinder 5a and the compressor 2 are connected by the control valve 3a, the second adsorption cylinder 5b and the vacuum pump 4 are connected by the control valve 3b, and the purge valve 7 and the product valve 8 are Also, the product valve 8 is switched to the closed state from the step of supplying the oxygen enriched gas from the first adsorption cylinder 5a to the oxygen tank 9, and the second adsorption cylinder 5b and the compressor 2 are connected by the control valve 3b. Then, go to the pressure equalization process. At this time, the air compressed by the compressor 2 is supplied to the first adsorption cylinder 5a and the second adsorption cylinder 5b, and the purge valve 7 is open, so that the air in the first adsorption cylinder 5a passes through the purge valve 7. To the second suction cylinder 5b. Furthermore, the air in the first adsorption cylinder 5a also moves to the second adsorption cylinder 5b via the control valve 3a and the control valve 3b. Therefore, in the pressure equalizing step, the first adsorption cylinder 5a is depressurized, the second adsorption cylinder 5b is pressurized, and the first adsorption cylinder 5a and the second adsorption cylinder 5b are at substantially equal pressure.

<Simultaneous pressure process>
In the pressure equalization step, when the pressure of the first adsorption cylinder 5a and the pressure of the second adsorption cylinder 5b become substantially the same, the first adsorption cylinder 5a and the compressor 2 are connected by the control valve 3a, and the second adsorption cylinder The process proceeds to the simultaneous pressurization step in which 5b and the compressor 2 are connected by the control valve 3b (the product valve is closed). At this time, since the first adsorption cylinder 5a and the compressor 2 are connected by the control valve 3a, and the second adsorption cylinder 5b and the compressor 2 are connected by the control valve 3b, the air compressed by the compressor 2 is Supplied to the first adsorption cylinder 5a and the second adsorption cylinder 5b, the pressure of the first adsorption cylinder 5a and the pressure of the second adsorption cylinder 5b are substantially the same. Therefore, in the simultaneous pressurization step, the first adsorption cylinder 5a and the second adsorption cylinder 5b are pressurized simultaneously.

<Pressure reduction process>
In the simultaneous pressurization step, when a predetermined time elapses, the control valve 3a is switched so as to connect the first adsorption cylinder 5a and the vacuum pump 4, and the purge valve 7 is switched to close so as to pressurize and depressurize. The process proceeds (the product valve is closed). At this time, since the second adsorption cylinder 5b and the compressor 2 are connected by the control valve 3b, the air compressed by the compressor 2 is supplied to the second adsorption cylinder 5b. Further, since the first adsorption cylinder 5a and the vacuum pump 4 are connected by the control valve 3a, the air in the first adsorption cylinder 5a is sucked into the vacuum pump 4. Accordingly, in the pressurization and depressurization step, the first adsorption cylinder 5a is depressurized and the second adsorption cylinder 5b is pressurized.

<Oxygen supply process>
Then, when a predetermined time elapses in the pressurizing and depressurizing process, the product valve 8 is switched to open, and the process proceeds to the oxygen supplying process. At this time, the oxygen-enriched gas in the second adsorption cylinder 5 b moves to the oxygen tank 9 via the product valve 8. Therefore, in the oxygen supply process, the pressure of the second adsorption cylinder 5b decreases, but the rate of increase of the pressure of the first adsorption cylinder 5a decreases.

<Purge process>
Then, when a predetermined time has elapsed in the oxygen supply process, the purge valve 7 is switched to open, and the process proceeds to the purge process. At this time, the air in the second adsorption cylinder 5b moves to the first adsorption cylinder 5a via the purge valve 7. Thereby, the air of the 1st adsorption cylinder 5a can be efficiently sucked by the vacuum pump 4. Therefore, in the purge process, the pressure in the first adsorption cylinder 5a and the pressure in the second adsorption cylinder 5b do not change much.

  As described above, the oxygen pressure taken out from the adsorption cylinders 5a and 5b during the large flow control is about 60 kPa as shown in FIG. 2B, whereas the adsorption cylinder 5a during the small flow control. , B, the pressure of oxygen taken out from b is about 140 kPa, as shown in FIG. Therefore, the take-out pressure at the time of the small flow rate control is substantially equal to about 140 kPa in the PSA oxygen concentrator in FIG.

<Characteristics of the oxygen concentrator 1 of the present embodiment>
In the oxygen concentrator 1 of the present embodiment, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than the predetermined flow rate, the oxygen-adsorbing gas is supplied from one adsorbing-cylinder vessel to the oxygen tank, and the other adsorption cylinder Since the two adsorption cylinders are in a pressurized state at the same time from when the oxygen enrichment gas is supplied to the oxygen tank, the pressure of the oxygen enriched gas taken out from the adsorption cylinder to the oxygen tank increases. Therefore, it is possible to secure the pressure set by the pressure reducing valve necessary for setting the correct flow rate with the flow rate regulator and the pressure required to flow the oxygen-enriched gas stably in the piping. When the flow rate of the concentrated gas is equal to or lower than the predetermined flow rate, it is possible to prevent the flow rate of the oxygen concentrated gas from becoming unstable.

  By the way, as shown in FIG.2 (b), at the time of large flow control, the pressure of the 1st adsorption cylinder and the 2nd adsorption cylinder fluctuates in the pressure range between the pressure higher than atmospheric pressure and the pressure lower than atmospheric pressure. On the other hand, during the small flow rate control, as shown in FIG. 3B, the pressures of the first adsorption cylinder and the second adsorption cylinder fluctuate in a higher pressure range than the conventional VPSA oxygen concentrator. Since the adsorption efficiency of the adsorbent decreases as the pressure increases, the adsorption efficiency of the adsorbent at the time of small flow control is lower than that at the time of large flow control.

  Here, in the oxygen concentrator, the adsorptive power of the adsorbent in the first adsorption cylinder and the second adsorption cylinder is set according to the maximum flow rate of the oxygen enriched gas taken out from the outlet. Therefore, even when the oxygen-enriched gas having the maximum flow rate is taken out from the outlet, the adsorbent adsorbs nitrogen from the air in the first adsorbing cylinder and the second adsorbing cylinder. it can. However, in this oxygen concentrator, when the flow rate of the oxygen-enriched gas taken out from the outlet is a small flow rate, the adsorbing force of the adsorbent in the first adsorption cylinder and the second adsorption cylinder may be excessive. In this case, the extracted oxygen-enriched gas contains a large amount of argon gas, and there is a problem that the oxygen concentration is lowered.

  In the oxygen concentrator 1 of the present embodiment, as described above, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than the predetermined flow rate, the pressures of the first adsorption cylinder and the second adsorption cylinder are low. Since it fluctuates in a pressure range higher than the atmospheric pressure, the adsorption efficiency of the adsorbent is lower than that during high flow control. Therefore, in this oxygen concentrator 1, when the flow rate of the oxygen-enriched gas taken out from the outlet 12 is small, it is possible to prevent the adsorbent adsorbing force from being excessive in the first adsorption cylinder and the second adsorption cylinder. Since it is possible, a high concentration oxygen-enriched gas can be taken out.

  As described above, when the flow rate of the oxygen-enriched gas taken out from the outlet 12 is larger than the predetermined flow rate, the adsorbent adsorbing power needs to be high in the first adsorption cylinder and the second adsorption cylinder. On the other hand, when the flow rate of the oxygen-enriched gas taken out from the outlet is less than or equal to a predetermined flow rate, it is better that the adsorbing power of the adsorbent in the first adsorption cylinder and the second adsorption cylinder is low. Therefore, in the oxygen concentrator 1 of the present embodiment, the adsorption efficiency of the adsorbent is changed by changing the pressure range of the first adsorption cylinder and the second adsorption cylinder between the large flow control and the small flow control. Thus, regardless of the flow rate of the oxygen-enriched gas taken out from the outlet, the oxygen-enriched gas having a high concentration can be taken out.

  As mentioned above, although embodiment of this invention was described based on drawing, it should be thought that a specific structure is not limited to these embodiment. The scope of the present invention is shown not by the above description of the embodiments but by the scope of claims for patent, and further includes all modifications within the meaning and scope equivalent to the scope of claims for patent.

  In the above-described embodiment, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than the predetermined flow rate, the simultaneous pressurization time when the two adsorption containers are simultaneously pressurized or the rotational speed of the compressor is oxygen It may be changed according to the flow rate of the concentrated gas. Therefore, when the flow rate of the oxygen-enriched gas taken out from the outlet is equal to or lower than the predetermined flow rate, the simultaneous addition is performed when the two adsorption containers are simultaneously pressurized in a case where the flow rate is lower than the predetermined amount and a case where the flow rate is higher than the predetermined amount. The pressure time or the rotation speed of the compressor may be changed.

  In the above-described embodiment, the pressurization / decompression step may be omitted. Accordingly, the simultaneous pressurization step may proceed directly to the oxygen supply step without performing the pressurization / decompression step. And the simultaneous pressurization process may overlap in the first half of the oxygen supply process. Specifically, the control valve may be switched while the product valve is opened and oxygen is extracted from the middle of the simultaneous pressurization step and oxygen is being extracted. In the oxygen supply step, the purge valve may be switched to open or closed.

  If this invention is utilized, it can prevent that the flow volume of the oxygen concentration gas taken out from an extraction port becomes unstable.

DESCRIPTION OF SYMBOLS 1 Oxygen concentrator 2 Compressor 3a, 3b Control valve 4 Vacuum pump 5a 1st adsorption cylinder (adsorption container)
5b Second adsorption cylinder (adsorption container)
6a, 6b Check valve 7 Purge valve 8 Product valve 9 Oxygen tank 10 Pressure reducing valve 11 Flow rate regulator 12 Outlet

Claims (2)

Two adsorption vessels having an adsorbent that selectively adsorbs nitrogen from the air and supplying oxygen-enriched gas to the oxygen tank;
For each of the two adsorption containers, a control valve that switches between a pressurized state in which air compressed by a compressor is supplied and a reduced pressure state in which the pressure is reduced by a vacuum pump;
An outlet for taking out the oxygen-enriched gas to the outside,
When the flow rate of the oxygen-enriched gas taken out from the outlet is below a predetermined flow rate,
The two adsorption vessels are added simultaneously from the time when the oxygen enriched gas is supplied from one adsorption vessel to the oxygen tank until the state where the oxygen enriched gas is supplied from the other adsorption vessel to the oxygen tank. The oxygen concentrator is characterized in that the control valve is controlled so as to be in a pressure state. When the flow rate of the oxygen-enriched gas taken out from the outlet is below a predetermined flow rate,
2. The oxygen concentrator according to claim 1, wherein the simultaneous pressurization time or the rotation speed of the compressor when the two adsorption containers are simultaneously pressurized is changed according to the flow rate of the oxygen enriched gas.

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