JPH0229602B2 - SANSOFUKAKI - Google Patents

Description

Detailed Description of the Invention [Technical Field] The present invention relates to an apparatus for stably and efficiently obtaining oxygen-enriched air from the atmosphere using a selectively permeable membrane that allows oxygen to permeate at a higher rate than nitrogen. The present invention relates to an oxygen enricher particularly suitable for medical use by removing excess moisture in oxygen-enriched air by means of specific water separation means. [Prior Art] In recent years, many patients have been suffering from respiratory system diseases such as asthma, emphysema, and chronic bronchitis, and oxygen inhalation is one of the most effective treatments for these diseases. However, when inhaling air with a high oxygen concentration of 60% or more in this oxygen inhalation method, it is known that it may be harmful, causing pneumonia symptoms and neurological disorders rather than having a therapeutic effect. 50% or less is generally used as it is safe to use. As a so-called oxygen enricher for supplying oxygen-enriched air with an oxygen concentration of 50% or less for a long time,
A membrane enrichment device using a selective oxygen-permeable membrane that allows oxygen to permeate at a higher rate than nitrogen has been proposed (see, for example, JP-A-51-6876 and JP-A-51-5291). . The characteristics of oxygen enrichers using this membrane method are that the oxygen and nitrogen selectivity of the membrane is generally in the range of 2 to 5, so the oxygen concentration obtained by general air separation is 50% or less; Also, since the permeation of water vapor is greater than that of nitrogen, the enriched air obtained by passing through the membrane comes out humidified, so humidification is not required especially when inhaling oxygen-enriched air, and the membrane itself is a super filter. Therefore, the membrane method oxygen enricher of the pressure reduction type is suitable for two reasons. It can be said to be the best enrichment device for medical use. By the way, as mentioned above, the oxygen-enriched air obtained by the membrane method has a higher water vapor permeation rate, so the water vapor contained in the air is concentrated. To explain this in more detail and quantitatively, in an oxygen selectively permeable membrane made of a general polymer, the water vapor permeation coefficient is usually an order of magnitude larger than the oxygen permeation coefficient. The side that comes into contact with the gas (hereinafter referred to as the source side, high pressure side, or atmospheric side) is under atmospheric pressure (usually 760 Torr), and the side where the gas permeates (hereinafter referred to as the permeation side, low pressure side, or enriched air side) is under reduced pressure. The proportion of water vapor in the enriched air that permeates through the membrane in the lower state and the concentration rate of water vapor in the atmosphere are approximately expressed by the following formula: t ₁ = RHR・hs/PL t ₀ = RHR・hs/PH y=t ₁ /t ₀ = PH/PL where t ₁ ; water vapor percentage in enriched air (v/v%) t ₀ ; water vapor percentage in the atmosphere (v/v%) RHR: relative humidity on the atmospheric side (%) hs: Saturated water vapor pressure at atmospheric temperature (mmHg) PL: Low pressure side pressure (Torr) PH: Atmospheric side pressure (usually 760) (Tor) y: Water vapor concentration ratio (-) in enriched air relative to the atmosphere In the range of practical vacuum pumps that can be used in medical oxygen enrichers, the low pressure side pressure PL is usually 100 to 200 Torr.
By applying the above formula, the high pressure side pressure PH can be calculated as follows.
Calculating the water vapor concentration factor y as 760Torr is 3.8
The water vapor contained in enriched air does not condense under reduced pressure or high temperature, but when the temperature shifts to normal pressure and/or the temperature drops, the water vapor condenses easily and the water vapor in the enriched air condenses. Water droplets form on the parts of the body. Such water droplets generated in the conduit can become a breeding ground for bacteria that enter or adhere to places where there is a possibility of contact with the atmosphere when not in use, such as the conduit coming out of the enricher, or the conduit Moisture adhering to the inside of the device is transported to the patient's enriched air intake area, causing not only discomfort to the patient but also causing coughing and sneezing. For this reason, in oxygen enrichers that employ the membrane method, means have been devised to actively remove excess water inside the enricher. In general, a conduit through which oxygen-enriched air coming out of a vacuum pump passes is configured in the form of a heat exchanger that efficiently contacts the income air, and the oxygen-enriched air is enriched in the heat exchanger-like conduit (hereinafter abbreviated as cooling means). A means (hereinafter abbreviated as water separation means) for cooling air to a temperature close to that of the intake air, condensing excess moisture, and separating the condensed excess moisture from enriched air containing non-condensed water vapor and oxygen-enriched air. installed to remove excess moisture. For this reason, in the water separator of the membrane type oxygen enricher, a means is taken to discharge water while leaking part of the oxygen-enriched air from the water outlet of the water separator. In other words, as a means of discharging this water, up until now,
Connect a flexible tube to the end of the water outlet, fill the tube with a yarn bundle of hydrophobic fibers such as acrylic fibers, and select the packing density and yarn bundle length appropriately to make the tube rich in oxygen. A method has been used in which flow resistance is created when oxygen-enriched air and moisture pass through, and the amount of leakage of oxygen-enriched air is minimized while the moisture is completely discharged. However, when hydrophobic fibers are used as a filler, they have poor water conductivity, and in order to discharge a large amount of condensed and separated water, it is necessary to carry a large amount of oxygen-enriched air with the discharged water. Therefore, an excess of oxygen enrichment membranes corresponding to the oxygen enriched air to be discharged together had to be installed and used, which was extremely disadvantageous economically. Furthermore, the exhaust noise generated when a large amount of oxygen-enriched air is discharged gives discomfort to the user of the oxygen enricher. This exhaust noise is very inconvenient when used at night when the noise level is low. [Object and Structure of the Invention] In order to eliminate the drawbacks of such a membrane-type oxygen enricher, the present inventors have devised a method for discharging water in a water discharge pipe provided in a membrane-type oxygen-enriched air water separation means. The present invention was achieved as a result of intensive research into the construction of a water discharge pipe that is economical and produces no discharge noise by minimizing the amount of oxygen-enriched air discharged along with the water. That is, the present invention is a device for obtaining air with a higher oxygen concentration than the atmosphere, which comprises an array of elements having a selectively permeable membrane that selectively allows oxygen to pass through than nitrogen; Atmospheric moving means for taking out oxygen-depleted air; oxygen-enriched air taking-out means for reducing the pressure inside the element below the pressure outside the element and taking out oxygen-enriched air from the inside; and the oxygen-enriched air taking-out means. cooling means for lowering the temperature of the oxygen-enriched air taken out from the oxygen-enriched air and condensing excess water vapor; water separation means for removing condensed moisture from the oxygen-enriched air; An oxygen enricher having an oxygen-enriched air delivery means for delivering oxygen-enriched air for use, wherein the water separation means connects an inlet for oxygen-enriched air from the cooling means to the oxygen-enriched air to the delivery means. and a discharge port for water separated from the oxygen-enriched air, and the water discharge port is equipped with a water discharge means filled with a fiber aggregate made of hydrophilic fibers and hydrophobic fibers. The present invention provides an oxygen enricher characterized by: The enricher of the present invention will be explained in more detail below using drawings, but the drawings merely show one embodiment of the present invention, and the present invention is not limited in any way by these drawings. Figure 1 schematically shows the configuration of an oxygen enricher using the membrane method, and the broken lines indicate the air flow on the atmospheric side.
The solid line indicates the flow of oxygen-enriched air, and the dashed line indicates the flow of discharged water. As shown by the broken line, the air A around the oxygen enricher is sucked through the air intake port 1 by the absorption power of the fan 3, is guided into the oxygen enricher, comes into contact with the cooling means 2, and then enters the module 4. The air (depleted air) that is sent and has a low oxygen concentration within the module 4 cools the vacuum pump 5, passes through the fan 3, passes through the passage 22, and is heated by the heat exchanger 12 and the passage as a heating means for the enriched air. 23, and is discharged as exhaust C from the air outlet 6 to the outside of the oxygen enricher. Such an air flow path is generally formed by constructing the internal casing structure of the oxygen enricher. A large number of elements (not shown) made of selective oxygen permeable membranes are arranged in the module 4. On one side of the permeable membrane of the element, there is a flow path through which room air is swept by the fan 3, and on the other side there is a flow path through which the indoor air is swept by the fan 3. A flow path is provided for the enriched air that has permeated through the membrane, and when the permeable membrane is formed in the form of a hollow fiber, the hollow fiber itself constitutes the flow path; In the case where there is a structure (generally called frame lamination or spiral), consideration is usually given to providing a flow path forming member on the permeation side to ensure a smooth flow of oxygen-enriched air. When there is a pressure difference on both sides of a permeable membrane having such a structure, air with a high oxygen concentration can be obtained on the permeate side depending on the pressure ratio on both sides. When the pressure ratio generating means, that is, the high pressure side is atmospheric pressure, a vacuum pump 5 is provided as a reduced pressure generating means, and the suction port 7 of the vacuum pump 5 is connected to a conduit means 8 for collecting enriched air generated in the element. 9, the enriched air is compressed in the vacuum pump 5, and is discharged from the discharge port 10 into the conduit 1 at a pressure higher than atmospheric pressure.
1. The other end of the conduit 11 is connected to a cooling means 2, in which the high temperature enriched air discharged from the discharge port 10 of the vacuum pump 5 and the swept room air exchange heat, and the high temperature The enriched air is cooled to a temperature close to room temperature, and excess water vapor contained in the enriched air is cooled and condensed. The thus cooled enriched air mixed with water droplets is led to the water separation means 14 through the conduit 13 and separated into enriched air containing condensed water and saturated water vapor.
5. Oxygen is introduced into a depressurizing means 16 for moisture adjustment such as an orifice and a valve, and a conduit 17, and while monitoring the flow rate with a flow meter 19, adjusts the flow rate with a flow control valve 18 to obtain the enriched air flow rate necessary for inhalation therapy. It is used as enriched air B. On the other hand, the water separated by the water separation means 14 is discharged via the water discharge means 20. At this time, when the cooling means 2 is simply brought into contact with the indoor air, the temperature of the enriched air to be cooled cannot be lower than the temperature of the indoor air, and is usually about 0.5 to 2 degrees Celsius higher than the indoor air temperature.
As mentioned above, the problem of water droplet adhesion in the transport conduit from the oxygen enricher arises. In order to prevent the occurrence of such problems, as shown in FIG. 1, a moisture retention function 21 made of a hygroscopic material is provided on the outer surface 21 (i.e., the area that comes into contact with the atmosphere) that is a part of the cooling means 2. The ejection means 2 is provided in at least a part of the functional part.
It is desirable to supply the water discharged from 0, evaporate the water there, and perform cooling by the heat of evaporation. The present invention provides the water discharge means 2 of such an oxygen enricher.
0, the flow resistance of water and the flow of air are minimized to minimize the amount of oxygen-enriched air discharged together with the discharged water as described above, and to ensure that all of the condensed water is discharged from there. It is characterized by extremely well balanced resistance under various conditions. That is, the water discharge means of the present invention is filled with a fiber aggregate consisting of both hydrophilic fibers and hydrophobic fibers. The water discharge means may have any shape, but a tubular body filled with the fiber aggregate is desirable as a shape that can be adapted to various operating conditions of the water separation means. The shape of the tubular body is such that its inner diameter is preferably 1 to 20 mm, particularly 2 to 8 mm, and the ratio L/D of inner diameter (D) to filling length (L) is preferably 10 to 1000, particularly 50 to 500. is preferred. The tubular body may be made of any material that maintains its tubular shape, such as copper, aluminum, iron, or other metals, glass, or resin, but flexible materials are preferred for assembly and inspection of the enricher. It is easy to operate when performing maintenance, and specific examples include soft materials such as polypropylene, polyvinyl chloride, silicone rubber, and polyethylene. Preferable materials for the hydrophobic fibers of the present invention include synthetic fibers such as polyester, acrylic, and polypropylene, and inorganic fibers such as glass fibers and metal fibers, and materials for the hydrophilic fibers include cotton, rayon, and hemp. Cellulose fibers and animal fibers such as wool are preferred. The shapes of such hydrophilic fibers and hydrophobic fibers are not particularly limited, and may be, for example, long fibers or short fibers, solid fibers or hollow fibers. Further, the thickness of the fibers may be such that when packed as an aggregate, the fibers can be brought into close contact with each other to such an extent that the water to be separated and removed can move through the aggregate according to the principle of capillary tubes. As a specific example, it is desirable that the average outer diameter of the fibers is in the range of 5 to 100 microns. The water discharge means in the present invention is filled with a fiber aggregate made of both hydrophilic fibers and hydrophobic fibers as described above, but the combination or mixture of the hydrophobic fibers and hydrophilic fibers to be filled is ,
It may be in any form, such as woven fabric, non-woven fabric, blended yarn, felt-like material, etc., or simply a mixture of short fibers, or a mixture or alignment of long fibers, but blended yarn is particularly preferred. . The mixing ratio of hydrophilic fibers and hydrophobic fibers is preferably from 0.1 to 3, expressed as the ratio of the weight of hydrophilic fibers to the weight of hydrophobic fibers.
The range of 0.1 to 1 is preferred, and the range of 0.3 to 0.7 is particularly preferred. Further, as for the filling state of the fiber aggregate, it is preferable that the fibers or threads are formed into a speed collector and filled in the tubular body along the longitudinal direction. In addition, at least a part of the fiber aggregate filled in the tubular body may be fixed in the tubular body by gluing, bundling, etc. at the end or middle part, but if it is not necessary, it may be fixed in particular. You don't have to. The filling rate in the filling part of the fiber aggregate is:
There is no particular limitation as long as the fibers are in close contact with each other to the extent that the water to be separated and removed can be moved by the capillary principle, but the lower limit is 5 vol% in order to keep the amount of oxygen-enriched air discharged low. is preferable, particularly preferably 10 vol%. Further, the upper limit of the filling rate is preferably 40 vol%, particularly preferably 20 vol%, from the viewpoint of water discharge amount. Furthermore, the water discharge means in the oxygen enricher of the present invention preferably satisfies the following conditions. That is, as a characteristic of the discharge means, its back pressure (difference between inlet side pressure and outlet side pressure 760 mmHg) is 10
mmHg, at room temperature, (a) the volume of air discharge V ₁ [cc (760
mmHg)/min] and the flow rate V of oxygen-enriched air (air passing through conduit 17 in Figure 1) [cc760mm]
Hg)/min] and the ratio V ₁ /V is 0.02 or less, and (b) the water discharge amount V ₂ [cc/min] and the oxygen when the inside is substantially filled with water. The ratio V ₂ /V to the enriched air flow rate V [cc (760 mmHg)/min] is
It is desirable that the value is 0.0001 or more. Furthermore, the ratio V ₁ /V is preferably in the range of 0.001 to 0.01, and the ratio V ₂ /V is preferably in the range of 0.0002 to 0.001. [Effects of the Invention] The oxygen enricher according to the present invention is a means for discharging excess moisture in oxygen-enriched air, and the amount of entrained discharge of oxygen-enriched air in a wide range of operating conditions is extremely small. The purpose of the present invention is to provide an economical oxygen enricher that can extremely reduce the loss of oxidized air. The present invention will be explained in more detail with reference to Examples below, but the oxygen enricher of the present invention is not limited to these Examples in any way. Example 1 In a membrane-type oxygen enricher as shown in FIG. 1, which incorporates an array of elements having ultrathin films of poly-4-methylpentene-1 molded on a porous polypropylene support on both sides, a water discharge means is used. As 20,
Inside a soft vinyl chloride tube with an inner diameter of 3 mm, 65% by weight of acrylic fibers (average outer diameter of approximately 13μ) and 35% by weight of wool (average outer diameter of approximately 16μ) blended yarn (length: 80cm, 4 single yarns)
5 pieces combined for each book, total dry weight 0.93
g) into a bundle and fill it almost uniformly (filling rate 14vol)
%) was incorporated and the suction side of the vacuum pump was operated at 160 mmHgab. at 25°C to obtain enriched air with an oxygen concentration of 40% at a flow rate of 6/min.
In that case, the back pressure of the water discharge means (i.e., the difference between the pressure on the water inlet side and the pressure on the outlet side of 760 mmHg) is 30 mm.
Hg, the average amount of water discharged is 0.4cc/min, and the average amount of oxygen-enriched air discharged along with it is 50c.c./min.
It was possible to operate stably for a long period of time under extremely low conditions such as min. As for the characteristics of the water discharge means itself, by varying the back pressure with the outlet side set to atmospheric pressure, the flow rate of air when the inside is substantially dry and the inside is substantially filled with water can be determined. When the amount of water discharged under the condition was measured, the values shown in Table 1 were obtained. Examples 2 and 3 In the same oxygen enrichment device as in Example 1, the water discharge means was filled with the same blended yarn as in the example and the filling rate was changed to 10 vol% and 19 vol%. The enricher was operated. In both cases, water could be discharged with a small flow rate of entrained enriched air, and the operation was extremely good. The characteristic values of the water discharge means in each case are also shown in Table 1. 【table】

[Brief explanation of drawings]

FIG. 1 shows an example of an oxygen enricher according to the present invention, in which 4 is an arrangement of elements, 3 is an atmosphere moving means, 5 is an oxygen-enriched air extraction means, and 2 is an arrangement of elements. 14 is a water separation means, and 20 is a water discharge means.

Claims (1)

[Scope of Claims] 1. A device for obtaining air with a higher oxygen concentration than the atmosphere, comprising an array of elements having a selectively permeable membrane that selectively allows oxygen to permeate over nitrogen, and supplying the atmosphere to the array. Atmospheric transport means for extracting crowded and oxygen-depleted air; oxygen-enriched air extracting means for reducing the pressure inside the element below the pressure outside the element and extracting oxygen-enriched air from the interior; and the oxygen-enriched air. cooling means for lowering the temperature of the oxygen-enriched air taken out from the extraction means and condensing excess water vapor; water separation means for removing condensed moisture from the oxygen-enriched air; An oxygen enricher having an oxygen-enriched air delivery means for delivering oxygen-enriched air for use, wherein the water separation means connects an inlet for oxygen-enriched air from the cooling means and an oxygen-enriched air delivery means to the delivery means. A water discharge means having an outlet for oxygen-enriched air and an outlet for moisture separated from the oxygen-enriched air, and the moisture outlet is filled with a fiber aggregate made of hydrophilic fibers and hydrophobic fibers. An oxygen enricher characterized by being equipped with. 2. The oxygen enricher according to claim 1, wherein the water discharge means is a tubular body filled with the fiber aggregate. 3. The oxygen enricher according to claim 1 or 2, wherein the fiber assembly is a bundle of mixed yarns of hydrophilic fibers and hydrophobic fibers.