JPH11128652A - Humidity regulation in hollow fiber membrane moistening device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a humidity regulating method capable of regulating the humidity of a concd. oxygen obtained from an oxygen concentrating device by a pressure swing adsorption method within a proper range. SOLUTION: In the case when a dehumidified air from which steam is separated by using a hollow fiber membrane unit 4 using a water separating hollow fiber membrane 5 as a diaphragm is sent to the oxygen concentrating device 8 by the pressure swing adsorption method to form the gaseous concd. oxygen, and the gaseous concd. oxygen is moistened with the steam at the secondary side of the water separating hollow fiber membrane, a flow rate of the formed gaseous concd. oxygen is detected with a flow rate detector 15, and the oxygen flow rate is controlled so that it may be a set flow rate, and also a pressure set value capable of keeping almost inverse relation to the flow rate is calculated based on the flow rate of the detected gaseous oxygen, and a pressure regulating valve 20 provided at a moisture conditioned oxygen discharge pipe 18 is controlled to regulate the oxygen humidity within the proper range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a concentrated oxygen gas generated from an oxygen concentrator by a pressure swing adsorption method (Pressure Swing Adsorption: hereinafter, referred to as PSA method). The present invention relates to a humidity adjusting method for adjusting a concentrated oxygen gas to a required humidity when humidifying using a humidifying device that separates water vapor using a water separation hollow fiber membrane as a diaphragm, using steam as a humidifying steam source.

[0002]

2. Description of the Related Art For example, concentrated oxygen gas generated in a home medical oxygen concentrator based on the PSA method is used as a respiratory aid for patients with respiratory illness. The concentrated oxygen gas thus obtained has a relative humidity of 1 to 3% RH, which is excessively dry, and is unsuitable for use by inhaling it directly into the human body.
Therefore, humidification is performed separately using a humidification device. Conventionally, as this humidifying device, a method was used in which a container containing water was provided in the middle of the oxygen conduit at the outlet of the concentrated oxygen, and the dried concentrated oxygen gas was bubbled in water to humidify the water. Since it is consumed, it is necessary to replenish the sterilized water periodically, and there is a problem that the handling of the user becomes complicated. Therefore, a method of collecting water vapor in the air using a water separation hollow fiber membrane has been developed.
Has been proposed in Japanese Patent Application Publication No.

[0003] The method of humidifying concentrated oxygen gas using the water separation hollow fiber membrane utilizes steam contained in atmospheric air in which the oxygen concentrator is placed, so that water replenishment is unnecessary and unpleasant. This is a very convenient method, as there is no bubble popping sound. However, when using this concentrated oxygen gas as a respiratory aid for patients with respiratory illness, it is necessary to consider a humidity control function for adjusting dry oxygen to a humidity suitable for inhaling a patient. There was a defect in the function of preventing dew condensation due to excessive humidification when the placed atmospheric humidity was high.

[0004] That is, air containing water vapor around the oxygen concentrator is compressed and concentrated by a compressor, and the water vapor contained in the air is used as a humidifying water vapor source to dry oxygen gas by water vapor obtained through a water separation hollow fiber membrane. Therefore, the humidity of the obtained humidified oxygen naturally changes according to the change in the humidity of the surrounding air. The concentration of water vapor supplied to the primary side of the water separation hollow fiber membrane also varies depending on the discharge pressure of the compressor. The pressure is substantially constant and does not become a factor for changing the humidity of the humidified oxygen. Therefore, the humidity of the humidified oxygen gas is mainly controlled by the humidity of the surrounding air in which the oxygen concentrating device is installed.

Next, the effect of the change in humidity in the surrounding air on the humidification of oxygen gas will be examined from both supply and demand. In the medical oxygen concentrator of the PSA type, generally, the generated oxygen gas concentration is 95 to 85 (volume).
%, Generated oxygen gas flow rate 0.2-5 liters / minute, maximum discharge pressure of the compressor 0.2 MPa (2 kgf / cm ² ≒ 2.94)
atm) and a discharge rate of 50 to 80 liters / min (under 1 atm) are frequently used. Here, for comparative study of the relationship between the amount of water vapor source and the humidity level and the demand, the following numerical values are calculated as an example.

Maximum discharge pressure of the compressor = 0.14 MPa (0.14 MPa４1.4 kgf / cm ² = 2.36 atm) Expected average pressure: Ppav = (2.36 + 1) /2=1.6
8 atm compressor discharge flow rate = 50 l / min (under 1 atm state) Average pressurized flow rate: Qpav = 50 / 1.68 = 30 l / min (at 1.68 atm pressurized state) Ambient air humidity: RHe = 30 % RH (1 atm) Average pressurized humidity: RHpav is 1 atm of ambient humidity 30% RH
Is pressurized to an average pressure of 1.68 atm.
pav = 30 × 1.68 = 50% RH (1.68 atm)

That is, as a water vapor source for oxygen humidification, the relative humidity is RH pav = 50% (1.68 atm) and the flow rate Qpa
v = 30 l / min (1.68 atm flow under pressure) is obtained. When this is used as a water vapor source to humidify 3 liters / minute (under 1 atm state) of dry oxygen to the same humidity of 50% RH, the supply amount of water vapor is 30/3 ≒ of the demand amount.
There is an amount ratio of about 10 times, which can be said to be a sufficient amount of water vapor.

[0008] This method works effectively when the humidity of the surrounding air in which the oxygen concentrator is installed is a certain value, but when the ambient air humidity is high, the humidity of the humidified oxygen gas increases. Too much, and a slight decrease in the temperature of the oxygen gas line generates condensed water, which hinders use. The reason for this is that the ambient humidity of the oxygen concentrator usually inevitably changes in the range of at least about 30 to 75% RH, including seasonal factors, and compresses this highly fluctuating steam source, This is because, because the system is used as a humidifying water vapor source, it cannot be coped with simply by adjusting the flow rate ratio, and it is difficult to obtain an appropriate oxygen humidity.

For example, in order to obtain a humidified oxygen humidity of about 50% RH under an ambient humidity of 30% RH,
When the ambient humidity is increased to 75% RH in a state where the flow rate of the raw material air is initially set to be linked to the flow rate of the oxygen gas, the amount of water in the raw material air is 2.
5 times. In this method, at the time of initial setting, the flow rate of the raw material air is determined so as to have a constant flow rate in conjunction with the flow rate of the oxygen gas, and even if the flow rate can be maintained constant, the amount of water vapor (concentration) contained in the raw material air changes Therefore, the oxygen gas humidity cannot be properly maintained. In addition, when the ambient air having a humidity of 75% RH is compressed to an average pressure of 1.68 atm, the humidity of the raw material air becomes supersaturated (75 × 1.68 = 75 × 1.68).
126%), and when the amount of oxygen gas used is a small flow rate, excessive humidification may occur, and there is a disadvantage that condensed water is generated when there is a slight temperature drop in the oxygen gas line. This phenomenon is particularly noticeable when the flow rate of the oxygen gas is small.

In order to avoid this drawback, there is a method of adjusting the flow rate of the raw material air so as to be linked to the flow rate of the oxygen gas so that the oxygen gas does not become excessively humidified even when the humidity of the surrounding air is high. When the ambient air humidity decreases below, the water vapor concentration in the raw material compressed air decreases, so that the replenishment amount and humidity level as a water vapor source for humidification become insufficient, and the humidification of oxygen gas becomes insufficient. For example, when the ambient air humidity is 75% RH and the oxygen gas usage flow rate is 0.5 L / min, the oxygen gas usage flow rate = 0.5 L / min (at 1 atm) Ambient air humidity = 75% RH (At 25 ° C., 1 atm) Raw material air humidity = 75 × 1.68 = 126% RH (at 2
5 ° C, 1.68 atm) Water vapor permeation efficiency of water separation hollow fiber membrane = 100% Desired oxygen humidity = 70% RH (at 25 ° C 1 atm) Value Qx l / min (at 25 ° C., 1.68 a
tm): Qx = (70/126) × 0.5 = 0.28 liter /
Like a minute.

In this calculation, for the sake of simplicity, the water vapor transmission efficiency of the water separation hollow fiber membrane is set to 100%. In practice, however, the efficiency must be taken into consideration. Taking into account the fact that the water vapor concentration on the raw material side decreases due to permeation transfer, it is needless to say that a flow rate larger than the calculated value is actually required. This flow rate is 30 liters / minute (at
25 ° C., 1.68 atm), which is about 1%, which indicates that a very small amount is sufficient. However, when the ambient air humidity is reduced from 75% RH to 30% RH, the humidity of humidified oxygen is reduced from 70% RH to 28% RH at once with the same interlocking flow rate ratio. Will be enough.

That is, the desired oxygen humidity is set to Oc [% RH],
Assuming that the raw material (compressed) air humidity is RHair [% RH] and the oxygen use flow rate is Qo [liter / min], the following general formula is obtained. Oc = (Qx / Qo) × RHair To obtain a desired constant oxygen humidity from this general formula,
Qx / Qo (Ratio of raw air flow rate to used oxygen flow rate)
It is not sufficient to keep the value of the constant, and it is understood that an appropriate oxygen humidity cannot be obtained unless countermeasures are taken against the ambient air humidity change. In addition, although the problem in the case of the medical oxygen concentrator by the PSA method has been mainly described here, the above-described problem is not limited to the medical oxygen concentrator and requires another humidity adjustment. The same applies to the case.

On the other hand, in the above-mentioned hollow fiber membrane type humidifier, dry air from which water vapor has been removed by the hollow fiber membrane is supplied to the adsorption tower of the oxygen concentrator. In this case, the hollow fiber membrane is thin and long. The pressure loss of the raw material compressed air between the inlet and the outlet increases, and this pressure loss tends to lower the adsorption performance in the adsorption tower of the oxygen concentrator. for that reason,
It is effective to consider the reduction of the pressure loss of the raw material compressed air in order to efficiently obtain the concentrated oxygen gas.

[0014]

SUMMARY OF THE INVENTION The technical problem of the present invention is to provide a novel humidity control which overcomes the disadvantages of the prior art relating to the humidification function when humidifying the concentrated oxygen obtained from the oxygen concentrator by the PSA method. It is to provide a method. A more specific technical object of the present invention is to detect the flow rate of the concentrated oxygen gas generated in the oxygen concentrator and adjust the oxygen humidity within an appropriate range by controlling the oxygen gas pressure according to the oxygen flow rate. It is an object of the present invention to provide a humidity control method. Another technical problem of the present invention is a humidity adjustment method that can adjust the oxygen humidity within an appropriate range according to the environmental humidity around the oxygen concentrator and the oxygen humidity after humidification in the humidity control oxygen extraction pipe. Is to provide.

[0015]

In order to solve the above-mentioned problems, a humidity control method according to the present invention uses a water vapor contained in compressed air of a raw material as a water vapor source for humidification and a water separation hollow fiber membrane as a diaphragm to separate water vapor. The dehumidified air from which the water vapor has been separated is sent to a PSA type oxygen concentrator to generate concentrated oxygen gas, and the concentrated oxygen gas permeates the secondary side of the water separation hollow fiber membrane. When humidified by the water vapor, the flow rate of the concentrated oxygen gas generated in the oxygen concentrator is detected by a flow rate detector,
While controlling so that the oxygen flow rate becomes the set flow rate,
Based on the detected oxygen gas flow rate, a pressure set value that maintains a substantially inverse proportional relationship with the flow rate is calculated, and a pressure control valve provided in the humidity control oxygen extraction pipe is controlled to control the pressure in the humidity control oxygen extraction pipe. A pressure change is applied to the oxygen gas to adjust the oxygen humidity within an appropriate range. In the above humidity adjustment method, the ambient humidity around the oxygen concentrator is detected, the pressure set value is corrected according to the humidity, the oxygen humidity is adjusted to an appropriate range, and the humidification in the humidity control oxygen extraction pipe is performed. Oxygen humidity can be adjusted within an appropriate range by detecting the oxygen humidity later and correcting the pressure set value according to the humidity.

[0016] In another humidity control method of the present invention, dehumidified air from which water vapor is separated by a hollow fiber membrane unit is supplied to a PS.
The concentrated oxygen gas is sent to the oxygen concentrating device of the A type to generate concentrated oxygen gas, and when the concentrated oxygen gas is humidified by the water vapor that has permeated into the secondary side of the hollow fiber membrane unit, the environmental humidity around the oxygen concentrating device is detected. A part of the dry concentrated oxygen gas introduced into the secondary side of the hollow fiber membrane in the hollow fiber membrane unit is branched to an oxygen bypass pipe having a flow rate adjusting means and a valve mechanism, and the valve mechanism is adjusted to the detected environmental humidity. Accordingly, the concentrated oxygen gas flowing through the oxygen bypass pipe is combined with the humidified oxygen gas in the delivery pipe of the hollow fiber membrane unit to adjust the oxygen humidity within an appropriate range.

In the humidity adjusting method of the present invention described above, the hollow fiber membrane unit is provided with a bypass passage having a throttle for adjusting the flow rate between the air supply port and the exhaust port of the compressed air. The pressure loss of the compressed air of the raw material can be reduced at the same time as the amount of water vapor permeating through is adjusted. According to such a method of the present invention, PSA
In the humidification of the concentrated oxygen obtained from the oxygen concentrator by the method, it is possible to obtain a humidity adjustment method which overcomes the disadvantages of the prior art relating to the humidity adjustment function. Depending on the oxygen humidity after humidification in the wet oxygen extraction pipe, the oxygen humidity can be adjusted within an appropriate range, and when the humidity in the raw material air changes, or when the usage flow rate of oxygen gas is changed In addition, it is possible to obtain a humidity adjustment method that can appropriately maintain the oxygen humidity.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in more detail with reference to the drawings. For example, in the case of a home medical oxygen concentrator, the user sets and uses an inhaled oxygen flow rate based on a doctor's prescription, but in the conventional method in which the oxygen humidity is not adjusted, the flow rate setting is changed. In the case, the oxygen humidity fluctuates, for example, when the set flow rate is increased in a state where the appropriate oxygen humidity is obtained, the oxygen humidity after the increase decreases, and conversely, when the flow rate setting is decreased. Is not preferable because oxygen humidity becomes excessive. When humidifying dried concentrated oxygen generated in a PSA type oxygen concentrator using a water separation hollow fiber membrane, the humidity of oxygen after humidification is within a range suitable for use even when various use conditions are changed. It is desired to be maintained and adjusted.

FIG. 1 shows an example of the configuration of a hollow fiber membrane type humidifier to which an example of the humidity adjusting method according to the present invention is applied. Using the water vapor contained in the compressed air as a humidification water vapor source, separating water vapor using a water separation hollow fiber membrane as a diaphragm, and sending the dried air from which the water vapor is separated to an oxygen concentrator to generate concentrated oxygen gas. The humidity is adjusted by adding water vapor separated by the water separation hollow fiber membrane. In particular, in this apparatus, humidification is performed according to a change in the flow rate of the concentrated oxygen gas generated in the oxygen concentrator. A pressure change is applied to the oxygen gas inside the apparatus to adjust the oxygen humidity within an appropriate range.

The device shown in FIG.
First, the raw air supplied through the raw air supply pipe 1 is compressed in the raw air compressor 2, cooled in the air cooling device 3, and then cooled by the primary air of the hollow fiber membrane unit 4 having the water separation hollow fiber membrane 5. Supplied to the side. In the hollow fiber membrane unit 4, the water vapor is transmitted through the water separation hollow fiber membrane 5, which is a separation membrane, and the dehumidified air from which the water vapor is separated and removed is sent out through the dehumidified raw material air outlet pipe 6. The gas is supplied to the adsorption column 8A or 8B in the PSA type oxygen concentrator 8 via the.
On the other hand, on the secondary side of the hollow fiber membrane 5 in the hollow fiber membrane unit 4, dry concentrated oxygen gas from the oxygen concentrating device 8 is supplied through an oxygen gas introduction pipe 9, and the dried oxygen gas permeates the hollow fiber membrane 5. Is humidified and sent out through the sending pipe 10.

The concentrated oxygen gas from which nitrogen gas or water vapor has been adsorbed and separated in the adsorption towers 8A and 8B is supplied to the check valve 11
The hollow fiber membrane unit is sent to the concentrated oxygen storage tank 12 via A and 11B, passes through a pressure regulating valve 13 for maintaining the pressure in the concentrated oxygen storage tank 12, and further passes through a flow rate control valve 14 and a flow rate detector 15. The oxygen gas is introduced from the oxygen gas introduction pipe 9 to the secondary side of the hollow fiber membrane 5 at 4. The oxygen gas introduction pipe 9 branches the oxygen bypass pipe 16 downstream of the flow rate detector 15 and joins the delivery pipe 10 of the hollow fiber membrane unit 4 through the flow rate adjustment throttle mechanism 17 to adjust the combined flow rate. The wet oxygen extraction pipe 18 is provided with a humidified oxygen pressure detector 19 and a pressure control valve 20. The flow rate adjusting throttle mechanism 17 determines the ratio of the amount of oxygen gas introduced into the secondary side of the hollow fiber membrane 5 in the hollow fiber membrane unit 4 to the amount of dehumidified concentrated oxygen gas directly guided to the humidity control oxygen extraction pipe 18. It can be adjusted manually or the like. The oxygen bypass pipe 16 provided with the flow rate regulating throttle mechanism 17
Is added for the purpose of coping with extreme operation conditions and the convenience of fine adjustment, and can be incorporated not only into external piping but also inside the hollow fiber membrane unit 4 to save space.

The oxygen flow controller 21 for controlling the flow control valve 14 is provided with a flow setting device 22 for enabling a user to set a desired oxygen flow. The oxygen flow controller 21 compares the set value of the flow rate in the flow rate setter 22 with the flow rate detected by the flow rate detector 15 so that the flow rate in the flow rate detector 15 becomes the set flow rate in the flow rate setter 22. The control signal is output to the flow control valve 14 to perform feedback control. It should be noted that a mass flow meter (mass flow meter) is preferably used as the flow detector 15 because the measurement gas has pressure fluctuations, but the present invention is not limited to this, and other types of flow meters can also be used.

The pressure control valve 20 provided in the humidity control oxygen outlet pipe 18 is controlled by an oxygen pressure controller 23. The oxygen pressure controller 23 has a flow detector 1
A pressure setting device 24 for calculating a humidified oxygen pressure set value that maintains a substantially inversely proportional relationship with the oxygen flow rate based on the oxygen flow signal from 5 and outputting it to the oxygen pressure controller 23 as a set value is provided. ing. As described above, with respect to the humidified oxygen gas pressure, the pressure set value calculated by the pressure setting device 24 and the oxygen pressure detected by the humidified oxygen pressure detector 19 are compared by the oxygen pressure controller 23, and the humidified oxygen pressure detector 19 is the pressure setting device 2
As a result of outputting a control signal to the pressure control valve 20 so as to have the set pressure value in 4 and performing feedback control, even if the oxygen flow rate setting is changed, the oxygen pressure is adjusted to keep the oxygen humidity within an appropriate range. Will be maintained.

In FIG. 1, a bypass flow rate regulating throttle 2
The material air bypass pipe 25 provided with 6 is added so that a part of the material air flows directly into the dehumidified material air outlet pipe 6 for the purpose of miniaturization, cost reduction, and convenience of fine adjustment of the entire apparatus. These are not limited to the external piping installed in parallel with the hollow fiber membrane unit 4, but may be incorporated into the hollow fiber membrane unit 4 for saving space. In addition, the flow control throttle valve 27 provided between the flow paths from which the oxygen gas concentrated in the adsorption towers 8A and 8B of the oxygen concentrator 8 is discharged,
A part of the concentrated oxygen gas is fed as a regeneration gas to the adsorption tower 8A or 8B (8B in the illustrated case) which is not connected to the dehumidified raw material air outlet pipe 6 by the switching valve 7 and is not in the adsorption separation step, In order to perform the regeneration purging, and to perform the adsorption separation in the adsorption tower 8A, the dehumidified air and the regeneration purge gas from the hollow fiber membrane unit 4 are sent along the arrow shown by the solid line in the figure. In the case of performing adsorption separation in the adsorption tower 8B, the dehumidified air and the regeneration purge gas are sent along the arrow shown by a dashed line in the figure, and are discharged from the regeneration purge gas outlet pipe 28 through the switching valve 7.

As a result of the above-described mutual complementation of the two systems of feedback control of flow rate and pressure, the oxygen humidity is maintained within an appropriate range. Next, the operation principle will be described in detail. Although the humidified oxygen is in a somewhat pressurized state in the pipeline upstream of the pressure control valve 20, the pressure is released in the humidified oxygen extraction pipe 18 after the pressure control valve 20, and the human body is almost at atmospheric pressure. Used for suction. Therefore, as the pressure of the humidified oxygen upstream of the pressure control valve 20, that is, the pressure of the humidified oxygen inside the hollow fiber membrane unit 4, increases, the pressure release effect increases, and the humidity downstream of the pressure control valve 20 can be reduced. .
This means that when reducing the desired oxygen flow rate, it is only necessary to increase the humidified oxygen pressure when it is desired to suppress the increase in the oxygen humidity due to the decrease in the oxygen flow rate.

Naturally, the lower the pressure of the humidified oxygen upstream of the pressure control valve 20, that is, the lower the pressure of the humidified oxygen inside the hollow fiber membrane unit 4, the smaller the pressure release effect, and the lower the humidity of the pressure control valve 20 becomes, It does not decrease and the humidity almost the same as that of the upstream side is maintained. This means that when increasing the desired oxygen flow rate, the humidified oxygen pressure should be reduced when it is desired to suppress a decrease in oxygen humidity due to an increase in the oxygen flow rate. That is, while the desired oxygen flow rate is accurately maintained by the feedback control, the pressure of the humidified oxygen inside the hollow fiber membrane unit 4 which is a part for humidifying the oxygen is automatically changed to a set value according to the oxygen flow rate. By performing feedback control, an appropriate oxygen humidity is maintained.

FIG. 2 shows an example of the configuration of another hollow fiber membrane humidifier for applying the humidity adjusting method according to the present invention. In the hollow fiber membrane humidifier shown in FIG. In order to change the humidified oxygen gas pressure inside the hollow fiber membrane unit 4 in accordance with the ambient humidity of 8, the environmental humidity detector 30 is connected to the pressure setting device 24 in the device of FIG. ing. The environmental humidity detector 30 detects the environmental humidity at the place where the oxygen concentrator 8 is installed, and automatically controls the set value in the pressure setting device 24 according to the level of the humidity. It should be maintained within an appropriate range. Specifically, this control is to correct the setting so that the humidified oxygen pressure set value is increased when the ambient humidity is high, and the humidified oxygen pressure is reduced when the humidity is low. The other configurations and operations of the apparatus shown in FIG. 2 are substantially the same as those shown in FIG. 1. Therefore, corresponding parts in the figure are denoted by the same reference numerals, and description thereof is omitted.

In another hollow fiber membrane type humidifier shown in FIG. 3, the humidifier inside the hollow fiber membrane unit 4 in the hollow fiber membrane type humidifier shown in FIG. The oxygen gas pressure is changed. For this purpose, an oxygen gas humidity detector 31 for detecting the humidified oxygen humidity (pressure release section) in the humidity control oxygen extraction pipe 18 is connected to the pressure setting device 24 in the device of FIG. The oxygen gas humidity detector 31 detects the oxygen humidity after humidification in the hollow fiber membrane unit 4 and automatically controls the set value in the pressure setting device 24 according to the level of the humidity. Humidity is maintained within an appropriate range. Specifically, this control is to correct the humidified oxygen pressure set value to be increased when the humidified oxygen humidity is high, and to be decreased when the humidified oxygen humidity is low. In addition,
Other configurations and operations of the apparatus of FIG.
Since there is substantially no difference from the case of the above, the same reference numerals are given to the corresponding portions in the figure, and the description thereof will be omitted.

FIG. 4 shows an example of the configuration of a hollow fiber membrane type humidifying apparatus to which still another example of the humidity adjusting method according to the present invention is applied. Here, the hollow fiber membrane unit 4 and the concentrated oxygen attached thereto are shown. Only the configuration of the humidification control system for the gas is shown, but the hollow fiber membrane unit 4 has a PS
It is needless to say that the hollow fiber membrane unit 4 and the humidification control system other than the humidification control system are substantially different from the hollow fiber membrane humidification apparatus of FIG. Absent.

The hollow fiber membrane unit 4 shown in FIG. 4 uses the water vapor contained in the raw material compressed air as a humidifying water vapor source and the water separated hollow fiber membrane as a diaphragm in the same manner as described with reference to FIG. The housing is composed of a lid 41, a hollow fiber membrane bundle holding case 42, a bellows-like flexible cylinder 43, and a flexible cylinder cover 44. A hollow fiber membrane bundle 45 made of a fluoropolymer is accommodated. The hollow fiber membrane bundle 45 bundles a large number of hollow fiber membranes for water separation and curves in a U-shape. Both ends of the hollow fiber membrane are consolidated by a hollow fiber bundle membrane consolidation resin, and the ends of the fiber membrane bundle are hollow. It is adhered and fixed to the holding case 42 so as to face the end surface of the thread film bundle holding case 42.

The lid 41 in the housing has an air supply port 4 for supplying compressed air containing water vapor as raw material compressed air.
7 and an exhaust port 48 for sending out dry air from which water vapor has been separated and removed, and a flow path communicating with the air supply port 47 and the exhaust port 48 is provided at the end of the hollow fiber membrane bundle holding case 42 at the end of the hollow fiber membrane bundle. The O-ring 49 is fastened and fixed to the holding case 42 as a sealing member. The cover 4
A bypass passage 50 having a fixed throttle 50a for adjusting the flow rate may be provided in the partition wall between the air supply port 47 and the exhaust port 48 in 1 as needed. This will be described later.

The hollow fiber membrane bundle holding case 42 has a gas inlet 51 and a humidified gas outlet 52 for the gas to be humidified at positions near both ends of the hollow fiber membrane bundle 45, respectively.
Baffles 53 and 54 for preventing gas passing therethrough from directly hitting the hollow fiber membrane bundle 45 are incorporated inside the inlet 51 and the outlet 52, and the hollow fiber membrane is curved in a U-shape. A flexible tube cover 44 is provided around a bellows-shaped flexible tube 43 that covers the bundle 45 with a space portion interposed therebetween, and the space between the flexible tube 43 and the flexible tube cover 44 is made of silicone resin or the like. The filling material 55 is filled. Therefore, the entrance 51
The gas flowing from the outlet to the outlet 52 flows along the hollow fiber membrane bundle 45 and reaches the outlet 52.

In the water separation hollow fiber membrane humidifier having the above-described structure, when compressed air containing water vapor is supplied from the air supply port 47 of the cover 41 of the housing, the hollow fiber membrane bundle 45 is supplied from one end to the other end. During the circulation, the water vapor permeates from the inside to the outside of each hollow fiber membrane, whereby the dry air from which the water vapor is separated and removed is sent out through the exhaust port 48 and supplied to the adsorption tower of the oxygen concentrator 8. On the other hand, the concentrated oxygen gas from the oxygen concentrator 8 passes through the inlet port 51 and the hollow fiber membrane bundle 4
5 circulates along the inside of the flexible tube 43, is humidified by the water vapor that has permeated through the hollow fiber membrane, and is sent out from the outlet 52.

As a humidification control system for the concentrated oxygen gas, an environmental humidity detector 56 for detecting the environmental humidity around the oxygen concentrator is provided.
A part of the dry concentrated oxygen gas introduced into the secondary side of the hollow fiber membrane bundle 45 in
A branch is made to an oxygen bypass pipe 59 having a valve mechanism 58, and the valve mechanism 58 is controlled in accordance with the environmental humidity detected by the environmental humidity detector 56. Delivery tube 52 of membrane unit 4
In step (1), the oxygen gas is combined with the humidified oxygen gas to adjust the oxygen humidity within an appropriate range. For example, when the humidified oxygen humidity detected by the environmental humidity detector 56 becomes equal to or more than a predetermined value, the valve mechanism is opened, and the dry oxygen is bypassed to lower the humidity. The aperture mechanism 57 can be a fixed aperture or a variable aperture. Also, as the valve mechanism 58, a solenoid valve or other automatic valve can be used, and not only the valve itself that performs on / off operation,
It is also possible to provide a responsive valve that maintains an opening according to an input signal.

In the hollow fiber membrane unit 4, the water vapor is removed by the hollow fiber membrane, and the dry air sent out from the exhaust port 48 is supplied to the adsorption tower of the oxygen concentrator by the PSA method to adsorb nitrogen gas. When enriching oxygen,
Since the hollow fiber membrane is thin and long, the pressure loss of the raw material compressed air between the inlet and the outlet increases, and this pressure loss tends to decrease the adsorption performance in the nitrogen adsorption tower built in the oxygen concentrator. . A bypass passage 50 provided as necessary in a partition wall between the air supply port 47 and the exhaust port 48 in the lid 41 is for reducing the pressure loss of the raw material compressed air, but is permeable to the hollow fiber membrane. It is possible to adjust the amount of water vapor and thereby adjust the humidification.

The bypass flow path 50 corresponds to the raw air bypass pipe 25 in FIG. 1, and therefore, the hollow fiber membrane unit 4 having the bypass flow path 50
However, it is needless to say that it can be used in any of the hollow fiber membrane type humidifiers described with reference to FIGS. The bypass passage 50 having the fixed flow restrictor 50a can be replaced with one having a different orifice diameter, or the orifice diameter can be adjusted manually or automatically.

[0037]

According to the method of the present invention described in detail above,
In the humidification of the concentrated oxygen obtained from the oxygen concentrator by the PSA method, it is possible to control the oxygen gas pressure according to the flow rate of the concentrated oxygen gas generated in the oxygen concentrator by overcoming the humidification function of the prior art. Thus, the oxygen humidity can be adjusted to an appropriate range, and further, the oxygen humidity can be adjusted to an appropriate range according to the environmental humidity around the oxygen concentrator and the oxygen humidity after humidification in the humidity control oxygen extraction pipe.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an example of a hollow fiber membrane type humidifier for applying a humidity adjustment method according to the present invention.

FIG. 2 is a configuration diagram showing another example of the hollow fiber membrane humidifier.

FIG. 3 is a configuration diagram showing another example of the hollow fiber membrane humidifier.

FIG. 4 is a configuration diagram showing another hollow fiber membrane unit and its humidification control system in the hollow fiber membrane humidifier.

[Explanation of symbols]

 2 Raw Material Air Compressor 4 Hollow Fiber Membrane Unit 5 Water Separation Hollow Fiber Membrane 8 Oxygen Concentrator 14 Flow Control Valve 15 Flow Detector 18 Humidity Adjustment Oxygen Extraction Pipe 19 Humidifying Oxygen Pressure Detector 20 Pressure Control Valve 22 Flow Rate Setting Device 24 Pressure Setting device 30, 56 Environmental humidity detector 31 Oxygen gas humidity detector 47 Air supply port 48 Exhaust port 52 Delivery pipe 58 Valve mechanism 59 Oxygen bypass pipe 50a Fixed throttle for flow rate adjustment 50 Bypass passage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B01D 63/02 B01D 63/02 C01B 13/02 C01B 13/02 A

Claims (5)

[Claims] 1. A hollow fiber membrane unit for separating water vapor by using water vapor contained in raw material compressed air as a water vapor source for humidification and using a water separation hollow fiber membrane as a diaphragm. The concentrated oxygen gas was sent to an oxygen concentrator by a variable adsorption method to generate concentrated oxygen gas, and when the concentrated oxygen gas was humidified by water vapor permeating the secondary side of the water separation hollow fiber membrane, the concentrated oxygen gas was generated in the oxygen concentrator. The flow rate of the concentrated oxygen gas is detected by the flow rate detector, and the oxygen flow rate is controlled so as to be the set flow rate, and based on the detected oxygen gas flow rate, the pressure is set so as to maintain an approximately inverse proportional relationship with the flow rate. Calculating the value, controlling the pressure control valve provided in the humidity control oxygen extraction pipe, giving a pressure change to the oxygen gas in the humidity control oxygen extraction pipe, and adjusting the oxygen humidity within an appropriate range. A method for adjusting humidity in a hollow fiber membrane type humidifying device, characterized by comprising: 2. The method according to claim 1, wherein the ambient humidity around the oxygen concentrator is detected, the pressure set value is corrected according to the detected humidity, and the oxygen humidity is adjusted within an appropriate range. Humidity adjusting method in a hollow fiber membrane humidifier. 3. The method according to claim 1, wherein the humidified oxygen humidity in the humidified oxygen extraction pipe is detected, and the pressure set value is corrected in accordance with the detected humidified oxygen humidity to adjust the oxygen humidity within an appropriate range. A method for adjusting humidity in a hollow fiber membrane humidifier. 4. A hollow fiber membrane unit for separating water vapor by using water vapor contained in the raw material compressed air as a humidifying water vapor source and using a water separation hollow fiber membrane as a diaphragm. When the concentrated oxygen gas is sent to the oxygen concentrator by the variable adsorption method to generate concentrated oxygen gas, and the concentrated oxygen gas is humidified by the water vapor that has permeated into the secondary side of the water separation hollow fiber membrane, the environmental humidity around the oxygen concentrator is reduced. A part of the dried and concentrated oxygen gas to be detected and introduced into the secondary side of the hollow fiber membrane in the hollow fiber membrane unit is branched into an oxygen bypass pipe having a flow rate adjusting means and a valve mechanism, and the valve mechanism is subjected to the detection. Control according to the environmental humidity, the concentrated oxygen gas flowing through the oxygen bypass pipe is combined with the humidified oxygen gas in the delivery pipe of the hollow fiber membrane unit, and the oxygen humidity is adjusted to an appropriate range. A method for adjusting humidity in a hollow fiber membrane humidifier. 5. The method according to claim 1, wherein a bypass passage having a flow rate regulating throttle is provided between an air supply port and a discharge port of the raw material compressed air in the hollow fiber membrane unit. A method for adjusting humidity in a hollow fiber membrane humidifier, wherein the amount of water vapor passing through a hollow fiber membrane is adjusted and the pressure loss of raw material compressed air is reduced.