JP2009219990A - Oxygen concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an oxygen generator capable of prolonging the life of its adsorbent. <P>SOLUTION: In the step 100, a power switch 47 is set to OFF and it is determined whether or not the operation time of the oxygen concentrator is not longer than 1 hour. In the step 110, it is determined whether or not it is timing to switch three-way valves 7, 9. In the step 120, a solenoid open/close valve 37 is set to ON to shut off a flow path 35. In the step 130, it is determined whether or not the oxygen generator has been in operation for not shorter than 1 hour since the issuance of the latest instruction to stop its operation. In the step 140, a compressor 5 is stopped because the oxygen concentrator has been in operation for 1 hour or longer. In the step 150, an equalizing valve 19 is kept in an open state longer than usual. In the step 160, it is determined whether or not it is timing to stop the device, and the timing to stop the device is awaited. In the step 170, the solenoid open/close valve 37 is set to OFF to open the flow path 35, and the entire operation is stopped. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an oxygen concentrator that uses an adsorbent that preferentially adsorbs nitrogen over oxygen and supplies a high concentration of oxygen to a patient or the like by a pressure fluctuation adsorption method.

Conventionally, a medical oxygen concentrator has been used for home oxygen therapy and the like as a device capable of supplying high concentration oxygen to a patient or the like.
As this type of oxygen concentrator, for example, an adsorption type oxygen concentrator in which an adsorbent that preferentially adsorbs nitrogen over oxygen is filled in a plurality of (for example, two) adsorption cylinders is known. As a home oxygen therapy device, a pressure fluctuation adsorption type oxygen concentrator using a compressor is used.

  In the pressure fluctuation adsorption oxygen concentrator, in general, air is supplied to the adsorption cylinder by an air supply means to make the inside of the cylinder pressurized, thereby adsorbing nitrogen in the air to the adsorbent and oxygen. The adsorption process, which is concentrated and taken out, and the regeneration process (exhaust process) in which the adsorption cylinder is desorbed by releasing the adsorption cylinder to the atmosphere and reducing the pressure, are repeated alternately or sequentially. Oxygen-enriched gas is generated.

  Further, in recent years, in order to efficiently obtain higher concentration of oxygen, the adsorption cylinder is opened to the atmosphere and depressurized to desorb the adsorbed nitrogen, and the product gas stored in the surge tank (oxygen enriched gas) By purging the inside of the adsorption cylinder to regenerate the adsorbent (see Patent Document 1), or by using the air compression means and exhausting until the inside of the adsorption cylinder becomes negative pressure A method for regenerating an adsorbent by desorbing adsorbed nitrogen has been proposed (see Patent Document 2).

However, since the medical oxygen concentrator is used for treatment of patients, long-term safety and stability are required, and therefore further improvement is required.
In other words, hydrophilic concentrators are often used as adsorbents in oxygen concentrators, but these adsorb moisture in the atmosphere with long-term use, and the nitrogen adsorption performance gradually declines. However, the measures described above have problems such as the complexity of the apparatus and the life of the hygroscopic agent, and the life extension effect of the adsorbent is recognized, but it is not always sufficient.

As a countermeasure against this, the applicant of the present application has proposed a method of removing moisture from the adsorbent using an oxygen-enriched gas as a purge gas when an instruction to stop the operation of the oxygen concentrator is given (see Patent Document 3).
JP 2003-180837 A JP-A-7-155526 JP 2005-31766 A

  The method of Patent Document 3 described above can also provide a great effect in suppressing the deterioration of the adsorbent, but further improvement in suppressing the deterioration of the adsorbent is required particularly in the medical field where higher performance is required. It was.

  The present invention has been made to solve the above-mentioned problems, and its purpose is to further improve the life of the adsorbent of an oxygen concentrator used at home for a long period of time, for example, long-term stable treatment of patients. It is to provide an oxygen concentrator that enables the like.

  (1) The invention of claim 1 is characterized in that at least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, and an air supply means (for example, a compressor) that supplies air to the adsorption cylinder and pressurizes it. And a pressure change switching means (for example, a switching valve) for controlling pressure increase / decrease in the adsorption cylinder, and in the pressure fluctuation adsorption type oxygen concentrator for generating oxygen concentrated gas from the air, the oxygen concentration If the operation time of the oxygen concentrator is less than 1 hour when the operation of the oxygen generator is instructed, the supply of the oxygen concentrated gas to the outside is cut off by an oxygen supply cut-off means (for example, a solenoid valve). In addition, in a state where the supply of the oxygen-enriched gas to the outside is shut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one of the adsorption cylinders. Purge to adsorption cylinder Supplied as scan, the steps of intake and exhaust to remove moisture of the adsorbent, and repeating at least 1 hour or more than 5 hours range after an instruction of the shutdown.

  In the present invention, for example, when the operation of the oxygen concentrator is instructed to be stopped by operating the operation stop switch, and the operation time of the oxygen concentrator is less than one hour, the oxygen supply cutoff means In this state, the oxygen concentrator gas is shut off, and the oxygen concentrator is operated to generate oxygen concentrated gas in the adsorption cylinder, and the generated oxygen concentrated gas is supplied as purge gas to the other adsorption cylinder. The intake and exhaust process (purge process) for removing moisture from the adsorbent is repeated for at least 1 hour and less than 5 hours after an instruction to stop operation is given.

  As described above, since not only nitrogen but also water is adsorbed by the adsorbent, the life of the adsorbent is reduced as it is. In addition, as shown in later experimental examples, the inventors' study clearly shows that the performance of the adsorbent decreases when the oxygen concentrator is operated for a short time of less than 1 hour. became.

  Therefore, in the present invention, when the operation of the oxygen concentrator is instructed to be stopped and the operation time of the oxygen concentrator is less than one hour, the supply of the oxygen concentrated gas to the outside is shut off and the operation is continued. Oxygen enriched gas is produced. This oxygen-enriched gas is a dried gas that contains high-concentration oxygen (for example, 95 mass% oxygen) and from which moisture has been removed by an adsorbent. Accordingly, by supplying this oxygen-enriched gas as a purge gas to the other adsorption cylinder, moisture can be released from the adsorbent in the adsorption cylinder and discharged out of the adsorption cylinder. Thereby, since the water | moisture content contained in adsorption agent can be reduced, the lifetime of adsorption agent can be extended efficiently.

Here, the purge gas is a gas for removing moisture from the adsorbent (ie, oxygen-enriched gas).
Hereinafter, the purge process performed when the operation time of the oxygen concentrator is less than one hour when the operation stop of the oxygen concentrator is instructed is referred to as a post-purge process.

  (2) In the invention of claim 2, at least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen, air supply means for supplying air to the adsorption cylinder and pressurizing, and the adsorption A pressure change adsorption type oxygen concentrator for generating oxygen enriched gas from the air, wherein the oxygen enriched gas is disposed downstream of the adsorption cylinder. Gas storage means (for example, a product tank) for storing, and when the operation stop of the oxygen concentrator is instructed, if the operation time of the oxygen concentrator is less than one hour, the oxygen supply shut-off means While the supply of the oxygen-enriched gas to the outside is shut off and the supply of the oxygen-enriched gas to the outside is shut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder And the generation The instruction to stop the operation of the intake and exhaust processes for removing the moisture of the adsorbent by supplying the oxygen enriched gas and the oxygen enriched gas stored in the gas storage means as purge gas to another adsorption cylinder. It repeats in the range for at least 1 hour and less than 5 hours after it exists.

  The present invention is basically the same as that of the first aspect of the present invention. However, since the gas storage means for storing the oxygen-concentrated gas is provided on the downstream side of the adsorption cylinder, the operation of the oxygen concentrator can be stopped. If the operation time of the oxygen concentrator is less than 1 hour when instructed, the generated oxygen-enriched gas and the oxygen-enriched gas stored in the gas storage means are supplied as purge gas to other adsorption cylinders. To remove moisture from the adsorbent.

As a result, the same effects as those of the first aspect of the invention can be obtained, and the oxygen-enriched gas stored in the gas storage means can be used, so that the moisture in the adsorbent can be more efficiently removed.
In the following, the process of removing moisture from the adsorbent using the oxygen-enriched gas stored in the gas storage means is also referred to as a post-purge process as described above.

  (3) According to a third aspect of the present invention, when the operation stop of the oxygen concentrator is instructed when the operation time of the oxygen concentrator is less than 1 hour, ) Or exhaust (exhaust gas from the adsorption cylinder) is waited until a switching timing is reached, and then a purge process from shut-off by the oxygen supply shut-off means to supply of purge gas is performed. To do.

  When the operation time of the oxygen concentrator is less than 1 hour and the operation stop of the oxygen concentrator is instructed, the pressure in one adsorption cylinder may increase excessively if the process immediately proceeds to the purge process. The pressure between the adsorption cylinders becomes imbalanced.

  Therefore, in the present invention, the process waits until the intake or exhaust gas switching timing is reached, and then the purge process is performed. Therefore, a purge gas (oxygen-enriched gas) having a moderately set pressure (for example, slightly higher than normal pressure) is used. , Can be supplied to the adsorption cylinder to remove moisture.

The reason why an excessive increase in pressure can be prevented by the operation of the present invention is as follows.
When the operation stoppage is instructed and the process proceeds to the purge process step, the pressure between the adsorption cylinders at the moment when the operation stop instruction is issued may not be uniform. Generally, since the switching timing of intake and exhaust is controlled by time, when one of the in-cylinder pressures is switched, the pressure increases correspondingly and the pressure between the adsorption cylinders becomes unbalanced. End up.

  On the other hand, in the present invention, the process waits until the intake or exhaust gas switching timing is reached, and then proceeds to the purge process, so that the pressure between the adsorption cylinders always starts from a uniform state. An imbalance does not occur and therefore an excessive increase in pressure can be prevented.

  (4) According to the invention of claim 4, when the operation of the oxygen concentrator is stopped after supplying the purge gas, the operation of the air supply means is stopped from the air supply means by the pressure increase / decrease switching means after the operation of the air supply means is stopped. The flow path for pressurization reaching the adsorption cylinder is blocked.

  In the present invention, when the operation of the oxygen concentrator is stopped, the operation of the air supply means is stopped, and then the flow path for pressurization from the air supply means to the adsorption cylinder is shut off by the pressure increase / decrease switching means. Therefore, there is an advantage that condensation does not easily occur.

The reason why condensation does not easily occur due to the operation of the present invention is as follows.
Normally, when the operation of the air supply means and the pressure increase / decrease switching means is stopped simultaneously when the power supply is stopped, the inside of the pipeline from the air supply means to the pressure increase / decrease switch means The compressed air will be trapped. Since the amount of saturated water vapor decreases in inverse proportion to the pressure of the air, the compressed air has a high relative humidity. However, since the compressed air at this time is heated by the compression heat and the heat generated by the air compression means, the amount of saturated water vapor increases, so it is in a state where condensation is difficult to occur. If it decreases, it will become easy to dew condensation.

  On the other hand, in the present invention, when stopping the operation of the oxygen concentrator, after stopping the operation of the air supply means, by blocking the flow path from the air supply means to the adsorption cylinder by the pressure increase / decrease switching means, Since the pressure in the pipeline is released, condensation is less likely to occur.

  The pressure increase / decrease switching means refers to the application of pressure in the adsorption cylinder by, for example, opening and closing the flow path from the air supply means to the adsorption cylinder or opening and closing the flow path from the adsorption cylinder to the outside. For example, a three-way selector valve that switches between a communication state of the air supply means and the suction cylinder (blocked from the outside) and a communication state of the suction cylinder and the outside (blocked from the air supply means). Or a combination of a plurality of two-position on-off valves.

(5) In the fifth aspect of the present invention, when the operation of the oxygen concentrator is stopped after supplying the purge gas, the adsorption cylinder that has generated the oxygen concentrated gas and the purge gas are supplied until the operation is stopped. The pressure equalizing valve that communicates with the suction cylinder is maintained in an open state.

  In the present invention, when the operation of the oxygen concentrator is stopped, the open state of the pressure equalizing valve that connects the adsorption cylinder that generates the oxygen-enriched gas and the adsorption cylinder that supplies the purge gas is maintained. The state of moisture and the like contained in the adsorbent is uniformized.

(6) The invention of claim 6 is characterized in that the supply amount of the purge gas is larger than the supply amount of the oxygen-enriched gas supplied from the adsorption cylinder during normal operation.
In the present invention, since the moisture is purged with a supply amount larger than the supply amount of the normal oxygen-enriched gas, the moisture can be sufficiently removed from the adsorbent.

(7) The invention of claim 7 is characterized in that the oxygen supply cutoff means is an electromagnetic on-off valve or a flow rate proportional control valve.
The present invention exemplifies oxygen supply blocking means. Here, as the flow proportional control valve, a solenoid type flow proportional control valve or an actuator (driven by a brushless DC motor, a stepping motor or the like) type flow proportional control valve can be adopted. When this flow rate proportional control valve is used, the flow rate can be adjusted, so that a manual flow rate setting device can be omitted.

  Next, an example (example) of the best mode of the present invention will be described.

  In this embodiment, oxygen is concentrated by adsorbing and removing nitrogen from the air using a nitrogen adsorbent (hereinafter referred to as an adsorbent), and this oxygen-enriched gas containing high-concentration oxygen is supplied to the patient. An example is a pressure fluctuation adsorption type medical oxygen concentrator to be supplied (hereinafter referred to as an oxygen concentrator).

a) First, each configuration for realizing the function of the oxygen concentrator of the present embodiment will be described.
As shown in FIG. 1, the oxygen concentrator 1 has a compressor 5, a pair of three-way switching valves (a first switching valve 7 and a second switching valve 9) on the air introduction path 3 from the upstream side, A pair of adsorption cylinders (first adsorption cylinder 11 and second adsorption cylinder 13) filled with an adsorbent are provided. The pair of adsorption cylinders 11 and 13 are provided with exhaust passages 15 for exhausting nitrogen through the three-way switching valves 7 and 9.

  Furthermore, on the downstream side of the pair of adsorption cylinders 11, 13, a first communication path 17 that communicates between the adsorption cylinders 11, 13 and a pressure between the adsorption cylinders 11, 13 provided in the first communication path 17. Prevents the backflow of the oxygen-enriched gas, the two-way valve (pressure equalizing valve) 19 for adjusting the pressure, the second communication path 21 communicating between the adsorption cylinders 11 and 13, the orifice 23 provided in the second communication path 21 A pair of check valves 25, 27, a product tank 29 for storing oxygen-enriched gas, a pressure regulator (regulator) 31 that adjusts the pressure of the oxygen-enriched gas, and a flow rate that is a rotary switch that sets the flow rate of the oxygen-enriched gas A setter 33 and an electromagnetic open / close valve 37 (that is, an electromagnetic valve that operates at the open / close 2 position) 37 that shuts off the flow path 35 that supplies oxygen-enriched gas to the outside are provided.

The oxygen concentrator 1 of this embodiment is a device having a continuous base flow rate of 5 L / min.
In this embodiment, as shown in FIG. 2, the oxygen concentrator 1 is equipped with an electronic control device 41 that controls the operation of the oxygen concentrator 1.

  The electronic control device 41 includes a well-known microcomputer 43. A power switch 47, a flow rate setting device 33 and the like are connected to an input portion 45 of the electronic control device 41, and a compressor 5 and three directions are connected to an output portion 49 of the electronic control device 41. The switching valves 7 and 9, the pressure equalizing valve 19, the electromagnetic on-off valve 37, and the like are connected.

  Therefore, a signal indicating the operation of the power switch 47 and a signal indicating the set flow rate set by the flow rate setting unit 33 are input to the electronic control device 41. The electronic control device 41 outputs control signals for controlling the operations of the compressor 5, the three-way switching valves 7 and 9, the pressure equalizing valve 19, the electromagnetic open / close valve 37, and the like.

b) Next, main operations of the oxygen concentrator 1 of the present embodiment having the above-described configuration will be described.
In the oxygen concentrator 1 of the present embodiment, oxygen concentration and adsorbent regeneration are performed by alternately repeating pressurization and pressure reduction in the first adsorption cylinder 11 and the second adsorption cylinder 13.

  For example, the compressor 5 sends compressed air to the first adsorption cylinder 11 via the first switching valve 7, and adsorbs nitrogen to the adsorbent to concentrate oxygen. When a predetermined time has elapsed, the switching direction is switched to the other second adsorption cylinder 13 by the switching valves 7 and 9, the first adsorption cylinder 11 is connected to the atmosphere side, and the adsorbed nitrogen is reduced in pressure. To be discharged.

  In this way, only the oxygen is extracted at the time of pressurization by the adsorption cylinders 11 and 13, and the oxygen-enriched gas is passed through the downstream product tank 29, the pressure regulator 31, the flow rate setting device 33, and the electromagnetic on-off valve 37. To the outside (and thus the patient).

  By repeating this operation alternately for both adsorption cylinders 11 and 13, 90% or more of concentrated oxygen can be obtained continuously, and further, by accumulating in the product tank 29, fluctuations are reduced and continuity is improved. Secured. Since the adsorbent adsorbs not only nitrogen but also moisture, the oxygen-enriched gas supplied from the pressurized adsorption cylinders 11 and 13 is dried.

  In particular, in this embodiment, when the power switch 47 of the oxygen concentrator 1 is turned off, if the operation time is less than one hour, the electromagnetic on-off valve 37 is turned on to turn on the flow path 35. In this state, the oxygen concentrator 1 is operated for 1 hour or longer.

  That is, in each of the adsorption cylinders 11 and 13, an adsorption process (a process in which air is pressurized and supplied to the adsorption cylinders 11 and 13 and nitrogen is adsorbed by the adsorbent to perform oxygen concentration) and an exhaust process (an adsorption cylinder 11 and 13). The internal gas (air etc.) is discharged under reduced pressure from 13 and the process of releasing the nitrogen adsorbed on the adsorbent and discharging it is repeated. That is, the post-purge process is performed by repeating the adsorption / desorption process of the adsorption cylinders 11 and 13 for at least one cycle.

  Thus, for example, the oxygen-enriched gas generated in the first adsorption cylinder 11 (that is, a dry high-concentration oxygen-concentrated gas from which moisture and nitrogen have been removed by the adsorbent) is used as the purge gas via the orifice 23 via the second adsorption cylinder. 13, the moisture is removed from the adsorbent filled in the second adsorption cylinder 13 and discharged to the outside. Similarly, the oxygen-enriched gas generated in the second adsorption cylinder 13 is supplied to the first adsorption cylinder 11 to remove moisture from the adsorbent and discharge it to the outside. These operations are repeated to sufficiently purge.

c) Next, the control process performed by the electronic control unit 41 will be described.
As shown in the flowchart of FIG. 3 and the timing chart of FIG. 4, in a state where the oxygen concentrator 1 is operating, in step 100, the power switch 47 is set to OFF and the operation time is less than 1 hour. Determine whether or not. Whether or not the operation time is less than 1 hour is determined by the time from when the power switch 47 is turned on to when it is turned off this time. If an affirmative determination is made here, the process proceeds to step 110, whereas if a negative determination is made, the present process is temporarily terminated.

  In step 110, since the previous stroke (see FIG. 4) after the power switch 47 is turned off is continued, the switching timing of the three-way switching valves 7 and 9 (that is, the switching timing of the intake stroke and the exhaust stroke). It is determined whether or not there is. If an affirmative determination is made here, the process proceeds to step 120, whereas if a negative determination is made, the process waits until the switching timing.

In step 120, the electromagnetic on-off valve 37 is turned on to block the flow path 35.
In the following step 130, it is determined whether or not it has been operating for one hour or more after an instruction to stop the operation this time (that is, after the power switch 47 is turned off this time). If a positive determination is made here, the routine proceeds to step 140.

  If it has been operating for one hour or more, it normally operates for one cycle or more, but if it has not operated for one cycle or more, it waits until one cycle is operated. This one cycle means that, for example, the intake stroke and the exhaust stroke are completed in the first adsorption cylinder 11, that is, the exhaust stroke and the intake stroke are completed in the second adsorption cylinder 13.

Note that the pressure equalizing valve 19 is turned ON for a predetermined period (equal pressure equalizing stroke) every half cycle, and the first communication passage 17 is opened, so that the pressures of the adsorption cylinders 11 and 13 are made uniform.
In step 140, since the compressor has been operated for one hour or more, the compressor 5 is stopped.

In the subsequent step 150, the open state of the pressure equalizing valve 19 is maintained longer than usual.
In the subsequent step 160, it is determined whether or not it is the device stop timing, and the system waits until that timing is reached.

In step 170, the electromagnetic on-off valve 37 is turned off to open the flow path 35, all operations are stopped, and this process is terminated.
d) Next, effects of the present embodiment having the above-described configuration will be described.

  In this embodiment, when the operation time is less than 1 hour when the power switch 47 is turned off, the electromagnetic on-off valve 37 is turned on to close the flow path 35 and the oxygen concentrator 1 is turned on for one cycle. Operate above. Then, the oxygen enriched gas generated in the first adsorption cylinder 11 is supplied as a purge gas to the second adsorption cylinder 13 through the orifice 23, and further, the oxygen enriched gas generated in the second adsorption cylinder 13 is used as the purge gas in the orifice 23. The moisture in the adsorbent in each of the adsorption cylinders 11 and 13 is removed by supplying the first adsorption cylinder 11 via the first adsorption cylinder 11 and the purge operation (post-purge process) is performed for 1 hour or more. Stop operation.

As a result, even if the user turns off the power switch 47 in a short time, the operation time of the oxygen concentrator 1 is always 1 hour or longer, so that the adsorbent can be prevented from deteriorating due to the short time operation.
In addition, this operation makes it possible to increase the supply amount of the purge gas from the supply amount of the oxygen-enriched gas supplied from the adsorption cylinders 11 and 13 during the normal operation, and to supply the oxygen-enriched gas at a high pressure. Moisture can be removed.

  Further, in this embodiment, when the operation time is less than 1 hour and the operation stop of the oxygen concentrator 1 is instructed, the operation waits until the intake or exhaust gas switching timing in the adsorption cylinders 11 and 13 is reached. After that, the flow path 35 is blocked by the electromagnetic opening / closing valve 37. Thereby, even if it is the structure which switches an intake stroke and an exhaust stroke for every fixed time, the pressure of oxygen concentration gas does not become excessive, and adsorption cylinders 11 and 13 which remove moisture from moderate pressure purge gas Can be supplied.

  Further, in this embodiment, when the operation of the oxygen concentrator 1 is stopped, the flow path 35 is opened by the electromagnetic on-off valve 37 after the compressor 5 is stopped. Therefore, there is an advantage that condensation does not easily occur.

  In addition, in this embodiment, when the operation of the oxygen concentrator 1 is stopped after supplying the purge gas, the pressure equalizing valve 19 is opened until the operation is stopped. The state of moisture) is made uniform.

e) Next, an experimental example performed to confirm the above-described effect will be described.
<Experimental example 1>
In this experimental example, the oxygen concentrator of Example 1 was operated in an environment of an ambient temperature of 35 ° C. and an ambient humidity of 90% (relative humidity) for one operation time of 30 minutes and a subsequent stop time of 3 hours ( The purge gas supply time is 1 hour), and the operation is repeated 2000 times (1000 hours operation), and the concentration of the oxygen-enriched gas at the start of operation is determined by an inspection device (for example, oxygen concentration using a limit current type zirconia oxygen sensor). ).

The results are shown in FIG. In addition, the horizontal axis of FIG. 5 integrates the operation time of each time.
As a comparative example, a similar experiment was performed without supplying purge gas after the power switch was turned off. The results are also shown in FIG.

  As is apparent from FIG. 5, in the case of purging for 1 hour or more (post-purge process) as in this embodiment, the oxygen concentration of the oxygen-enriched gas is less decreased even when the oxygen concentrator is used for a long period of time. It is preferable because the life of the adsorbent is long.

  On the other hand, in Comparative Example 1 in which the post-purging process is not performed and in Comparative Example 2 in which the post-purging process is performed for a short time (for example, 30 minutes), the oxygen concentration of the oxygen-enriched gas decreases quickly when used for a long time ( For example, when operated for 1000 hours, the oxygen concentration drops to 93% or less), and the life of the adsorbent is short, which is not preferable.

<Experimental example 2>
In this experimental example, when the operation time for one time is changed, it is examined how much the oxygen concentration decreases after long-term use.

  Specifically, in Comparative Example 3, the oxygen concentrator of Example 1 was operated in an environment of 35 ° C. and an ambient humidity of 90% (relative humidity) for one operation time of 30 minutes and a stop time. The operation was repeated 2000 times (with no purge gas supply time) for 3 hours (1000 hours operation), and the concentration of the oxygen-enriched gas when the operation was started was measured using an inspection device. The result is shown in FIG.

  Further, as Comparative Example 4, one operation time was set to 1 hour, and the other conditions were the same as in Comparative Example 3, and the concentration of the oxygen concentration gas was measured. Furthermore, as Comparative Example 5, one operation time was set to 2 hours, and the other conditions were the same as in Comparative Example 3, and the concentration of the oxygen concentration gas was measured. The results are also shown in FIG.

  As is clear from FIG. 6, when the operation is repeated for a long time (for example, 1 hour or 2 hours), the oxygen concentration of the oxygen-enriched gas does not decrease so much even if a long period of time elapses. It can be seen that if the operation of one operation time is short (for example, 30 minutes), the oxygen concentration of the oxygen-enriched gas decreases when a long period of time has elapsed.

  Therefore, by performing the operation of the present invention, it is preferable because the life of the adsorbent can be extended even when an operation with a short operation time is repeated.

Next, the second embodiment will be described, but the description of the same contents as the first embodiment will be omitted.
As shown in FIG. 7, the oxygen concentrator 51 of the present embodiment includes a compressor 53, a pair of three-way switching valves (a first switching valve 55, a second switching valve 57), and a pair of like the first embodiment. An adsorption cylinder (first adsorption cylinder 59, second adsorption cylinder 61), a pressure equalizing valve 63, an orifice 65, a pair of check valves 67 and 69, a product tank 71, a pressure regulator (regulator) 73, and the like are provided.

  In this embodiment, a flow rate proportional control valve 75 is used in place of the flow rate setting device and the electromagnetic on-off valve of the first embodiment. The flow rate proportional control valve 75 can be adjusted in its opening degree by a stepping motor (not shown), whereby the flow rate of the oxygen-enriched gas supplied to the outside can be adjusted and the flow path 79 can be shut off.

Furthermore, in this embodiment, bypasses 81 and 83 that bypass the pair of check valves 67 and 69 are provided, and purge controls 85 and 87 are provided in the bypasses 81 and 83.
In the present embodiment, as in the first embodiment, when the post-purge process is performed, the purge control valves 85 and 87 are controlled to open, so the oxygen-enriched gas in the product tank 71 is used for the post-purge process. be able to.

  In addition, this invention is not limited to the said Example at all, and it cannot be overemphasized that it can implement with a various aspect in the range which does not deviate from the summary of this invention.

FIG. 3 is an explanatory diagram showing a basic configuration of an oxygen concentrator of Example 1. It is explanatory drawing which shows the electrical structure of the electronic controller of the oxygen concentrator of Example 1. FIG. 3 is a flowchart illustrating processing performed by the electronic control device according to the first embodiment. 3 is a timing chart illustrating processing performed by the electronic control device according to the first embodiment. 6 is a graph showing the experimental results of Experimental Example 1. 10 is a graph showing an experimental result of Experimental Example 2. It is explanatory drawing which shows the basic composition of the oxygen concentrator of Example 2. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 51 ... Oxygen concentrator 5, 53 ... Compressor (air supply means)
7, 9, 55, 57 ... three-way switching valve (pressure-intensifying switching means)
11, 13, 59, 61 ... Adsorption cylinder 19, 63 ... Pressure equalizing valve 37 ... Electromagnetic on-off valve (oxygen supply cutoff means)
33 ... Flow rate setting device 23,65 ... Orifice 29,71 ... Product tank 75 ... Flow rate proportional control valve (Oxygen supply cutoff means)

Claims (7)

At least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen;
Air supply means for supplying and pressurizing air to the adsorption cylinder;
Pressure increase / decrease switching means for controlling pressure increase / decrease in the adsorption cylinder;
With
In the pressure fluctuation adsorption type oxygen concentrator for generating oxygen enriched gas from the air,
When the operation time of the oxygen concentrator was less than 1 hour when the operation stop of the oxygen concentrator was instructed,
Shutting off the supply of the oxygen-enriched gas to the outside by an oxygen supply shut-off means;
In a state where the supply of the oxygen-enriched gas to the outside is shut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder, and the generated oxygen-enriched gas is transferred to another adsorption cylinder An oxygen concentrator characterized in that an intake and exhaust process for removing moisture from the adsorbent, which is supplied as a purge gas, is repeated for at least 1 hour and less than 5 hours after the instruction to stop the operation. At least two adsorption cylinders filled with an adsorbent that preferentially adsorbs nitrogen over oxygen;
Air supply means for supplying and pressurizing air to the adsorption cylinder;
Pressure increase / decrease switching means for controlling pressure increase / decrease in the adsorption cylinder;
With
In the pressure fluctuation adsorption type oxygen concentrator for generating oxygen enriched gas from the air,
Gas storage means for storing the oxygen-enriched gas downstream of the adsorption cylinder;
When the operation time of the oxygen concentrator was less than 1 hour when the operation stop of the oxygen concentrator was instructed,
Shutting off the supply of the oxygen-enriched gas to the outside by an oxygen supply shut-off means;
With the supply of the oxygen-enriched gas to the outside cut off, the oxygen concentrator is operated to generate oxygen-enriched gas with at least one adsorption cylinder, and the generated oxygen-enriched gas and the gas storage means The stored oxygen-enriched gas is supplied as a purge gas to another adsorption cylinder, and the intake and exhaust processes for removing moisture from the adsorbent are performed at least 1 hour and less than 5 hours after the instruction to stop the operation. Oxygen concentrator characterized by repeating in the range of.   When the operation time of the oxygen concentrator is less than 1 hour and when the operation stop of the oxygen concentrator is instructed, after waiting until the switching timing of intake or exhaust in the adsorption cylinder is reached, The oxygen concentrator according to claim 1 or 2, wherein a purge process from shut-off by the oxygen feed shut-off means to supply of purge gas is performed.   When stopping the operation of the oxygen concentrator after supplying the purge gas, after the operation of the air supply means is stopped, the pressurization switching means for pressurization from the air supply means to the adsorption cylinder The oxygen concentrator according to any one of claims 1 to 3, wherein the flow path is blocked.   When the operation of the oxygen concentrator is stopped after supplying the purge gas, a pressure equalizing valve that communicates the adsorption cylinder that has generated the oxygen concentrated gas and the adsorption cylinder to which the purge gas has been supplied until the operation is stopped. The oxygen concentrator according to any one of claims 1 to 4, wherein the valve open state is maintained.   The oxygen concentrator according to any one of claims 1 to 5, wherein a supply amount of the purge gas is larger than a supply amount of the oxygen concentrated gas supplied from the adsorption cylinder during normal operation.   The oxygen concentrator according to any one of claims 1 to 6, wherein the oxygen supply cutoff means is an electromagnetic on-off valve or a flow rate proportional control valve.