JP4904127B2 - Pressure fluctuation adsorption type oxygen concentrator - Google Patents

Description

  The present invention relates to an oxygen concentrator for separating and using oxygen-enriched air and oxygen-enriched gas from the atmosphere. More specifically, regarding the pressure fluctuation adsorption type oxygen concentrator, the volume of the oxygen-enriched gas produced due to the reduced performance of the adsorbent filled in the air supply means and / or the adsorbent bed as the integration time elapses. The present invention relates to an improved pressure fluctuation adsorption type oxygen concentrator capable of preventing a decrease in concentration and stably supplying an oxygen-enriched gas having a predetermined concentration or more to a user without being affected by the elapsed time.

  In recent years, the number of patients suffering from chronic respiratory diseases such as pulmonary emphysema, pulmonary tuberculosis sequelae and chronic bronchitis tends to increase. As a treatment method for such patients, oxygen inhalation therapy for inhaling high concentration oxygen is performed. The oxygen inhalation therapy is a treatment method for inhaling oxygen gas or oxygen enriched gas to the diseased patient. Examples of the supply source of therapeutic oxygen gas or concentrated oxygen gas include the use of high-pressure oxygen cylinders, liquid oxygen cylinders, oxygen concentrators, etc., which can withstand long-term continuous use and are easy to use. For this reason, cases of using oxygen concentrators are increasing.

  The oxygen concentrator is an apparatus that can separate and concentrate oxygen in the air. As an apparatus for separating and concentrating oxygen, one or a plurality of adsorbent beds is packed with an adsorbent capable of selectively adsorbing nitrogen in the air from the viewpoint of obtaining high concentration oxygen of 90% or more Adsorption type oxygen concentrators are widely known. Among them, a pressure fluctuation adsorption type oxygen concentrator using a compressor as a pressure fluctuation apparatus is widely spread in the world. Such an apparatus normally supplies compressed air from a compressor to one or a plurality of adsorbent beds filled with an adsorbent that selectively adsorbs nitrogen, and adsorbs nitrogen by bringing the inside of the adsorbent bed into a pressurized state. This is an apparatus for obtaining high concentration oxygen by repeating an adsorption process for obtaining unadsorbed high concentration oxygen and a desorption step for desorbing nitrogen by depressurizing the inside of the adsorption bed.

  To compensate for the change in oxygen concentration over time and the decrease in oxygen concentration due to aging of the device, and to keep the oxygen concentration constant, the oxygen concentration of the oxygen-enriched gas is detected by an oxygen sensor, and the compressor air volume and adsorption / desorption An apparatus that maintains product oxygen concentration by feedback control of cycle time or the like is known (Patent Document 1).

  In the maintenance and inspection of the oxygen concentrator, it is important to check the accumulated usage time of the device and perform various maintenance management. As a method of confirming the accumulated usage time, use the hour meter provided in the device. A method and a management method using an external terminal (Patent Document 2 and Patent Document 3) are widely used.

Special Table 2000-516854 JP 2002-306601 A Japanese Unexamined Patent Publication No. 7-227516

  In home oxygen therapy, the amount of oxygen to be inhaled is determined by a doctor's prescription, and when using a pressure fluctuation adsorption oxygen concentrator as an oxygen supply source, it is assumed that an oxygen concentration of 90% or more is always generated. The prescription oxygen flow rate and the inhalation time are determined based on the blood oxygen concentration data.

  Zeolite adsorbents such as 5A, 13X, and Li-X used as adsorption beds for pressure fluctuation adsorption type oxygen concentrators have the property of selectively adsorbing water, and therefore adsorb moisture in the raw material air. As a result, the adsorbent deteriorates with time, and the oxygen concentration tends to decrease gradually. During the operation of the equipment, moisture is exhausted together with the adsorbed nitrogen in the desorption process that exhausts and regenerates the nitrogen adsorbed on the adsorbent, but the remaining moisture gradually accumulates, so the adsorbent usually takes about 2 years. It is necessary to exchange.

  Since many users are patients with chronic respiratory diseases, such oxygen concentrators are used continuously over a long period of time, such as one year or two years. However, since the prescription oxygen amount is determined by the severity of the disease, in the case of mild patients, oxygen inhalation is performed only during exercise (during activity) or with a prescription such as several hours per day. For example, in the case of a patient who inhales oxygen for 1 hour per day, the usage time of the oxygen concentrator is 365 hours (15.2 days) in one year, and the cumulative rest time is 8395 hours. When such intermittent operation is performed, moisture diffusion in the adsorption cylinder due to the temperature change of the apparatus caused by repeated intrusion and intermittent operation of moisture during the downtime is promoted. As a result, the adsorbent rapidly deteriorates within a few months, causing a decrease in the generated oxygen concentration.

  In the present invention, in response to such deterioration of the oxygen concentrator due to pause, the oxygen concentration generated by controlling the compressor air volume and the adsorption / desorption cycle based on the operation and pause information of the device and the deterioration of the oxygen with time are reduced. The present inventors have found an apparatus that compensates for the accompanying decrease in oxygen concentration and keeps the oxygen concentration constant.

  That is, the present invention includes at least one adsorption bed filled with an adsorbent capable of selectively adsorbing nitrogen over oxygen, air supply means for supplying air to the adsorption bed, and air from the air supply means. In the pressure fluctuation adsorption type oxygen concentrating apparatus provided with the flow path switching means for repeating the adsorption process for supplying the adsorbent bed and taking out the concentrated oxygen, and the desorption process for depressurizing the adsorbent bed and regenerating the adsorbent at a fixed timing. And a control means for controlling the air supply amount of the air supply means and / or the switching time of the flow path switching means based on the operation time information of the operation time measurement means. A pressure fluctuation adsorption type oxygen concentrating device is provided.

  The present invention further includes a calculation unit that calculates an operation time ratio and / or an accumulated downtime based on the operation time information of the operation time measurement unit, and the control unit determines whether the air supply unit has an air flow based on the calculation result. The operation amount ratio is not more than a predetermined value (particularly not more than 0.02) and the cumulative pause time is not less than the prescribed time (particularly, characterized by controlling the supply amount and / or the switching time of the flow path switching means. In the case of 2000 hours or more), the control means performs control for increasing the air supply amount of the air supply means or control for delaying the switching time of the flow path switching means. A device is provided.

  Further, according to the present invention, when the operation time ratio is not more than a predetermined value and the accumulated pause time is not less than the predetermined time, the control means controls the air supply amount of the air supply means or the switching time of the flow path switching means. It is characterized by comprising display means for displaying that the control is executed, and such display means is means for transmitting and displaying control information to a management center that manages information through a communication line. A pressure fluctuation adsorption type oxygen concentrating device is provided.

In the pressure fluctuation adsorption type oxygen concentrator of the present invention, it is possible to maintain the generated oxygen concentration by predicting the apparatus deterioration due to the intermittent operation and responding in software.
Furthermore, it is not necessary to initially increase the adsorbent filling amount or to increase the compressed air supply amount of the air supply means from the beginning, thereby reducing the power consumption, cost, weight, etc. of the pressure fluctuation adsorption type oxygen concentrator. Product design becomes possible.

An embodiment of the pressure fluctuation adsorption type oxygen concentrator of the present invention will be described with reference to the drawings while comparing with the prior art. However, the present invention is not limited to these examples.
In FIG. 1, 1 is an oxygen concentrator, and 3 is a user (patient) who inhales humidified oxygen-enriched air. The pressure fluctuation adsorption-type oxygen concentrator 1 includes an external air intake filter 101, a compressor 103, a switching valve 104, an adsorption cylinder 105, a check valve 106, a product tank 107, a pressure regulating valve 108, a flow rate setting means 109, and a filter 110. Thereby, oxygen-enriched air obtained by concentrating oxygen gas from the raw material air taken in from the outside can be produced.

  First, the raw material air taken in from the outside is taken in from an air intake port provided with an external air intake filter 101 for removing foreign matters such as dust. At this time, the normal air contains 1.2% of oxygen gas of about 21%, nitrogen gas of about 77%, argon gas of 0.8%, water vapor and the like. In such an apparatus, only oxygen gas necessary as a breathing gas is concentrated and extracted.

  The oxygen gas is taken out from the adsorption cylinder 105 filled with an adsorbent made of zeolite or the like that selectively adsorbs the nitrogen gas molecules rather than the oxygen gas molecules. The source air is pressurized and supplied by the compressor 103 while sequentially switching 105, and approximately 77% of nitrogen gas contained in the source air is selectively adsorbed and removed in the adsorption cylinder 105.

The adsorbing cylinder 105 is formed of a cylindrical container filled with the adsorbent, and usually a multi-cylinder type of three or more cylinders is used in addition to the one-cylinder type and the two-cylinder type. In order to produce oxygen-enriched air from the raw material air, it is preferable to use a multi-cylinder type adsorption cylinder 105. Further, as the compressor 103, a swing type air compressor may be used, and a rotary type air compressor such as a screw type, a rotary type, or a scroll type may be used. Further, the power source of the electric motor that drives the compressor 103 may be alternating current or direct current.
Oxygen-enriched air mainly composed of oxygen gas that has not been adsorbed by the adsorption cylinder 105 flows into the product tank 107 through a check valve 106 provided so as not to flow backward to the adsorption cylinder 105.

  Note that the nitrogen gas adsorbed by the adsorbent filled in the adsorption cylinder 105 needs to be desorbed from the adsorbent in order to adsorb the nitrogen gas again from the newly introduced raw material air. For this purpose, the pressurized state realized by the compressor 103 is switched to a reduced pressure state (for example, an atmospheric pressure state or a negative pressure state) by the switching valve 104, and the adsorbent is regenerated by desorbing the adsorbed nitrogen gas. In this desorption process, in order to increase the desorption efficiency, oxygen-enriched air may be allowed to flow back as a purge gas from the product end side of the adsorption cylinder or the product tank 107 during the adsorption process.

  Oxygen-enriched air is produced from the raw air and stored in the product tank 107. The oxygen-enriched air stored in the product tank 107 contains high-concentration oxygen gas, for example, 95%, and the supply flow rate and pressure are controlled by the pressure regulating valve 108, the flow rate setting means 109, etc. Supplied to the vessel 201 and humidified oxygen-enriched air is supplied to the patient. In such a humidifier, a moisture permeable membrane module having a moisture permeable membrane takes in moisture from external air and supplies it to dry oxygen-enriched air, a bubbling humidifier using water, Alternatively, a surface evaporation humidifier can be used.

  The set value of the flow rate setting unit 109 is detected, and the control unit 401 controls the rotation speed of the motor of the compressor 103 to control the amount of air supplied to the adsorption cylinder 105. When the set flow rate is low, the amount of generated oxygen is suppressed and the power consumption is reduced by reducing the number of rotations.

  The operating time measuring means 402 employs a real time clock (RTC) to measure the start time and stop time of the operating time of the oxygen concentrator. Based on the measurement result, the operation time ratio (operation rate) and the accumulated stop time are calculated. When the operation time ratio is equal to or less than the predetermined value and the accumulated stop time is equal to or more than the predetermined time, the control means 401 supplies the air to the compressor 103. Control for increasing the amount or control for delaying the switching time of the switching valve 104 is performed.

  When the patient is mild and the required oxygen supply amount is small and the prescription time is short, the operation time of the oxygen concentrator is shortened, resulting in intermittent operation. When the device is driven, the temperature inside the device increases, and when the device stops, the temperature inside the device decreases. The same applies to the adsorption cylinder 105. When the apparatus stops and the apparatus internal temperature decreases, the temperature of the adsorption cylinder 105 also decreases, and the internal pressure of the adsorption cylinder 105 becomes negative. The switching valve 104 is closed when the apparatus is stopped, but is easily influenced by negative pressure and sucks outside air. In the case of a multi-cylinder type in which a part of the adsorption cylinder is opened to the atmosphere, the influence becomes more remarkable.

  In addition, in the case of an oxygen concentrator having a two-cylinder type and a multi-cylinder type adsorption cylinder, one adsorption cylinder always ends in the adsorption process, so that moisture in the raw material air remains in the adsorption cylinder. As the temperature of the adsorption cylinder decreases, there is a possibility that moisture condensation will occur due to a decrease in saturated vapor pressure.

  Such a problem does not depend on the set flow rate value, but depends on the operation time ratio (operation rate) and the accumulated downtime. Taking the oxygen concentrator in FIG. 1 as an example, FIG. 2 shows the continuous operation time per day and the frequency of occurrence of a decrease in oxygen concentration. It can be seen that the rate of decrease in oxygen concentration is high in the apparatus in which the operation time per day is 1 to 2 hours. In such a short-time use, the user does not necessarily perform oxygen inhalation every day. Such a decrease in oxygen concentration occurs after 2000 hours or more in cumulative rest time. Fig. 3 shows the relationship between the cumulative operating time ratio (operating rate) of the oxygen concentrator and the frequency of occurrence of oxygen concentration reduction due to moisture absorption deterioration of the adsorbent. When the operating rate is 4% or less, the problem of oxygen concentration reduction occurs. It shows a tendency to increase rapidly at 2% or less.

  When the operation time ratio is 2% or less and the accumulated pause time exceeds 2000 hours or more, the control means 401 controls the drive motor rotation speed of the compressor 103 to generate an air supply amount that is higher than usual. Control to increase the oxygen concentration of the oxygen-enriched air. As another means, the switching time of the switching valve 104, which is a flow path switching means, is controlled, and the adsorption time is extended by increasing the adsorption / desorption time, thereby increasing the oxygen concentration.

  When such control is applied, the user is alerted with an LED display or the like, and a prediction of a decrease in oxygen concentration due to moisture absorption deterioration is made. When a system that collectively manages the usage information and abnormality information of each device through the communication network line is used at the information center, etc., the control information is sent to the management center that manages the information through the communication line and the control information is displayed. By doing so, it is possible to perform maintenance before the abnormal stop of the device.

The schematic diagram of the pressure fluctuation adsorption type oxygen concentrator which is an embodiment of the oxygen concentrator of the present invention. The related figure of the continuous operation time per day of an oxygen concentrator, and the occurrence frequency of oxygen concentration fall. The relationship figure of the operation time ratio of an oxygen concentrator, and the occurrence frequency of oxygen concentration fall.

Explanation of symbols

1: Oxygen concentrator 2: Waterless humidifier 3: User
101: External air intake filter
103: Compressor
104: Switching valve
105: Adsorption cylinder
106: Check valve
107: Product tank
108: Pressure regulating valve
109: Flow rate setting method
110: Filter
201: Humidifier
301: Oxygen concentration sensor
302: Flow sensor
401: Control means
402: Operation time measurement means

Claims (8)

At least one adsorbent bed filled with an adsorbent capable of selectively adsorbing nitrogen rather than oxygen, air supply means for supplying air to the adsorbent bed, and air from the air supply means being supplied to the adsorbent bed In a pressure fluctuation adsorption type oxygen concentrator having a flow path switching means for repeating an adsorption process for extracting concentrated oxygen and a desorption process for depressurizing the adsorbent bed and regenerating the adsorbent at a fixed timing, an operation time measuring means for the apparatus And a control means for controlling the air supply amount of the air supply means and / or the switching time of the flow path switching means during operation of the apparatus based on the operation time information of the operation time measurement means. The pressure fluctuation adsorption type oxygen concentrator characterized by this.   Computation means for computing an operation time ratio and / or cumulative rest time based on the operation time information of the operation time measurement means is provided, and based on the calculation result, the control means is the air supply amount of the air supply means and / or 2. The pressure fluctuation adsorption type oxygen concentrator according to claim 1, wherein a switching time of the flow path switching means is controlled.   3. The pressure according to claim 2, wherein when the operating time ratio is equal to or less than a predetermined value and the accumulated pause time is equal to or longer than a predetermined time, the control means performs control to increase the air supply amount of the air supply means. Fluctuation adsorption type oxygen concentrator.   4. The control unit performs control to delay the switching time of the flow path switching unit when the operation time ratio is equal to or less than a predetermined value and the accumulated pause time is equal to or longer than a predetermined time. Pressure fluctuation adsorption type oxygen concentrator.   The pressure fluctuation adsorption type oxygen concentrator according to claim 3 or 4, wherein the predetermined value of the operation time ratio is 0.02 or less.   The pressure fluctuation adsorption type oxygen concentrator according to claim 3 or 4, wherein the predetermined value of the accumulated pause time is 2000 hours or more.   When the operation time ratio is not more than a predetermined value and the accumulated pause time is not less than the predetermined time, the control means controls the air supply amount of the air supply means or the switching time of the flow path switching means. The pressure fluctuation adsorption type oxygen concentrating device according to any one of claims 2 to 6, further comprising display means for displaying the fact that the gas is flowing.   8. The pressure fluctuation adsorption type oxygen concentrator according to claim 7, wherein the display means is means for transmitting and displaying control information to a management center that manages information through a communication line.

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