JP2003079735A - Medical oxygen concentrator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a quiet, compact and light pressure type oxygen concentrator to be used for at-home oxygen therapy. SOLUTION: In the pressure swing absorption type oxygen concentrator having at least one adsorption cylinder filled with adsorbents which can selectively adsorb nitrogen rather than oxygen and an air compressor for supplying air to the adsorptive cylinder while pressurizing the air and/or for exhausting air while reducing the pressure, the air compressor is a helical compressor provided with a helical blade.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an oxygen concentrator for separating and concentrating oxygen from the air, and more particularly to a pressure fluctuation adsorption type oxygen concentrator used for home oxygen inhalation therapy for medical purposes.

[0002]

2. Description of the Related Art A medical oxygen concentrator used for home oxygen therapy uses air as a raw material and concentrates about 21% oxygen contained therein to 40% or 90% or so. As the method, a membrane-type oxygen concentrator that uses an oxygen-enriched membrane that selectively permeates oxygen, and an adsorbent that selectively adsorbs nitrogen such as zeolite are used, and the adsorption cylinder filled with this material is used as a raw material. There is a pressure fluctuation adsorption type oxygen concentrator that adsorbs and separates nitrogen by adding air. The oxygen concentration concentrated by the former oxygen concentrator is about 40% and the latter is about 90%.
At present, the latter is predominant, and the present invention relates to the latter.

The pressure fluctuation adsorption type oxygen concentrator is 5 A
Type zeolite or 13X type zeolite, or SiO ₂ / Al ₂ O ₃ ratio
Packing high-performance Li zeolite, etc., in which at least 88% or more of the AlO ₄ tetrahedral unit is 2.0 to 3.0 and associated with Li cations in one, two, or more adsorption columns Then, using a compressor to supply air under pressure to adsorb nitrogen, separate oxygen and switch the flow path,
PS that desorbs adsorbed nitrogen by reducing the pressure to atmospheric pressure
Various types of A-type or VPSA-type devices that have improved desorption regeneration efficiency by reducing the pressure of the adsorption column to a vacuum state are being supplied to the market.

[0004]

The basic performance required for an oxygen concentrator used for home oxygen therapy is as follows:
It has quietness, small size and light weight, and energy saving. This is due to the following reasons.

That is, the oxygen concentrator used for home oxygen therapy is often used 24 hours a day, and at night, it is required that the operation sound of the device is a quiet device that does not disturb sleep of patients including family members. To be done.

[0006] Further, since the patient lives on the oxygen produced by the device, if there is a failure, the maintenance staff will be called immediately for repair and the maintenance staff will be available 24 hours a day. ing. It is an important requirement for the maintenance personnel to be small and lightweight so that one person can easily carry the repaired equipment or replace the equipment.

Further, the quality of life of the patient (QO
L), the patient is looking forward to going out and traveling, and conventionally, in this case, the oxygen filled in the cylinder is used. However, the amount of gas is finite, and the gas is emptied for several hours, so frequent filling is required. For this reason, many people need help, and the reality is that they cannot easily go out or travel. Therefore, if the oxygen concentrator is small and lightweight, it can be easily loaded into a car and transported, and can be used at hotels and inns. At home, the oxygen concentrator can be freely moved to facilitate a range of action. Can be extended to That is, there is a demand for reduction in size and weight in terms of patient QOL.

In terms of power consumption, most of the cost of the device itself is a health insurance burden and the burden on the patient is small, but the operating cost is a burden on the patient, and the patient operates continuously for 24 hours a day. Therefore, the electricity bill becomes a heavy burden, and a device with low power consumption is an essential requirement.

Next, regarding the three requirements required for these oxygen concentrators, the prior art has the following modes.

(1) Quietness The source of the operating noise in the device is the operating noise of the air compressor that takes in and compresses the raw material air, and the pressure fluctuation is accompanied by the pressure switching and exhaust of the adsorption cylinder of the adsorption type oxygen concentrator. The exhaust noise that is generated is the main one.

The exhaust noise can be relatively well silenced by attaching a high performance silencer. However, the operation sound of the air compressor contains a lot of low-frequency sound accompanied by vibration, and it is difficult to reduce it easily. At present, there are a piston type, a vane type, and a scroll type air compressors that are used for medical oxygen enrichment. In the vane type, the carbon used is worn out, and black carbon appears on the secondary side, and a filter is required to remove this. Furthermore, this filter also has to be replaced frequently. In addition, the wear life of carbon vanes is 2000
Since it is up to 4000 H, and maintenance is frequently required, the piston type is mainly used.

Regarding the noise of the piston type air compressor, the noise level of the air compressor alone of the class normally used for the above-mentioned oxygen concentrator is in the range of 80 to 60 dBA.
This is due to the vibration of the air compressor caused by the operation of the piston and the low-frequency operation noise caused by the torque fluctuation of the electric motor. As means for preventing the propagation of vibrations to others, it is disclosed in Japanese Patent Laid-Open No.
As shown in Japanese Patent Application Laid-Open No. 3-242901, a means for floating by means of a spring or a vibration-proof rubber is adopted, and it is disclosed in JP-A-60-2.
As shown in Japanese Patent Laid-Open No. 8044 and Japanese Patent Laid-Open No. 59-274654, sound is enclosed by a double soundproof box. However, it is not possible to completely seal it, it is necessary to cool the heat generated by the drive motor and air compression,
A fan is installed. However, noise leaks to the outside through the inlet and outlet of this cooling air, so a curved passage is provided to prevent this. Since various soundproofing measures have been taken in this way, the device is large and heavy, weighing 40 to 60 kg, and it is difficult for one maintenance person to hold and go up and down the stairs of a building.

In the scroll type air compressor, a pair of swinging scroll plates each having a pair of involute shapes as main components and a fixed scroll plate are overlapped with each other so as to face each other. In addition, each process of intake, compression, and discharge is advanced. Japanese Patent Laid-Open No. 11-92105 proposes an oxygen concentrator equipped with a scroll compressor.
However, in the scroll compressor, since the gap formed between the involutes becomes the air leak point, it is necessary to process the involutes with high accuracy,
Usually, three-dimensional machining is required, which is very expensive. On the contrary, in order to reduce the price,
If the machining accuracy is reduced, the gap between the involutes when rotated once has a large gap at a certain point and a large air leak, and at a certain point, the involutes come into contact with each other to cause noise. For this reason, there is a problem in that the original features of high efficiency and low noise of the scroll cannot be achieved.

(2) Small size and light weight Another factor is that the device is large and heavy due to the structure for satisfying the above-mentioned quietness. Another factor is to reduce the size and weight of the device. The number of cylinders in the vessel and its operating method have a great influence.

(3) Low power consumption By strengthening the internal seal structure of the air compressor, the loss work can be reduced, so that a highly efficient air compressor can be provided. That is, since the main power consumption part in the oxygen concentrator is the air compressor,
The improvement in efficiency of this portion realizes low power consumption, and thus has a great effect. At the same time, reducing lost work
It will have the effect of suppressing excessive heat generation and vibration.

[0016]

SUMMARY OF THE INVENTION The present invention provides a quiet, compact and lightweight pressure swing adsorption type oxygen concentrator for use in home oxygen therapy as described above. Therefore, the present inventor has found the following oxygen concentrator as a result of diligent studies on such problems.

That is, according to the present invention, at least one adsorption column filled with an adsorbent capable of selectively adsorbing nitrogen over oxygen and an air compression for supplying air under pressure to and / or exhausting under reduced pressure to the adsorption column. A pressure fluctuation type oxygen concentrator having a compressor, wherein the air compressor is a helical compressor equipped with a helical blade.

In particular, at least one groove is provided on the side surface of the helical blade, and the gap between the helical groove and the helical blade on the rotor of the helical compressor is filled with magnetic fluid. An oxygen concentrator is provided.

Further, the electric motor for driving the air compressor is a brushless electric motor driven by a DC power source,
The present invention also provides an oxygen concentrator, which is equipped with an inverter.

[0020]

1 is a schematic view of a medical oxygen concentrator of the present invention. In such an oxygen concentrator, compressed air is supplied by a compressor to an adsorption column filled with a 5A type zeolite as an adsorbent that selectively adsorbs nitrogen rather than oxygen, and an oxygen-concentrated gas with an oxygen concentration of 90% is taken out to obtain a humidifier. To the patient with respiratory disease via the
It is a two-cylinder pressure fluctuation adsorption type oxygen concentrator that supplies at a flow rate of min.

The air compressor is a helical blade type air compressor having a compression ratio in the range of 1.5 to 3.0 and an exclusion volume in the range of 50 cc / rev or less. The electric motor that drives the air compressor is a brushless DC electric motor having the ability to operate at 5000 rpm or less, and by controlling this with an inverter, the rotation speed can be arbitrarily changed.

The helical blade type compressor is, for example, a rotary compressor described in Japanese Patent Laid-Open No. 2000-87886. The compressor was developed as a compressor for compressing a fluid such as a refrigerant such as a refrigerator, and as shown in FIG. 2, a cylindrical cylinder and a helical blade that divides the compression chamber, and a motor rotating shaft are biased. The cored roller is a main constituent element, and the roller moves in the axial direction to be compressed by the roller rotating while keeping the clearance inside the cylinder.

In the present invention, such a compressor is used in an oxygen concentrator as a compressor for compressing air. Since the conventional reciprocating piston compressor has a clearance volume, the discharged air contains the air retained in the cylinder, and its flow rate does not increase on the high rotation side and is not proportional to the rotation speed. Further, since the compression ratio is determined by the valve opening / closing timing on the outlet side, the pressure of the discharged air also changes in proportion to the pressure on the secondary side.
With a helical blade compressor, the clearance volume is zero, so the air discharged is always fresh air, its flow rate is proportional to the number of revolutions, and the compression ratio is fixed, so the pressure is always constant. Was found to be the most suitable oxygen concentrator.

The oxygen yield of the adsorption column used in the oxygen concentrator is dramatically improved by using fresh air having a constant pressure and a stable residence time. Therefore, a 3L model of a reciprocating piston type is used. Compared to a compressor, the air flow rate can be reduced by about 10%, and the adsorption cylinder itself can be downsized by about 20%. Therefore, by adapting the helical blade type compressor to an oxygen concentrator, the adsorption cylinder can be downsized. Can be converted.

In the conventional helical blade type compressor for compressing the refrigerant, as shown in FIG. 4 (a), the helical blade and the helical groove provided in the roller contain the refrigerant,
Liquid sealing is possible. Since the helical compressor mounted on the oxygen concentrator of the present invention is air-compressed, it is possible to use grease in order to secure the seal of such a portion and install a filter on the outlet side for use. However, as a means for ensuring the cleanliness of air and preventing the evaporation of grease in a vacuum, the labyrinth seal effect can be obtained by using a grooved blade as shown in FIG. 4B instead of grease. It is desirable to express and use in a dry state. Further, as shown in FIG. 4C, by filling the helical blade and the helical groove of the rotor with magnetic fluid instead of grease, it is possible to seal and to omit the installation of the filter.

[0026]

By applying the helical blade type compressor to the oxygen concentrator, it is possible to reduce the capacity of the compressor itself and the adsorption cylinder itself at the same time. In other words, since the helical blade type compressor is a rotary compressor, it inherently has little vibration. Therefore, the large-scale anti-vibration rubber and anti-vibration springs that have been used in the past have been simplified to reduce the size of the device. Can be planned.

Further, by arranging the cylinder of the compressor in a vertical direction in the vertical direction, vibration absorption is achieved by utilizing the gyro effect that the compressor develops, and by disposing the adsorption cylinder above the cylinder, the oxygen concentrator It is also desirable to form the outer shape into a simple cylindrical shape.

Further, in the helical blade type compressor, since the rotational speed and the flow rate are linearly proportional to each other, the power saving effect is exhibited especially by the capacity control by the combination of the brushless DC motor and the inverter.

[0029]

EXAMPLES Examples and comparative examples of oxygen concentrators that realize a flow rate of 3 L / min with an oxygen concentration of 91% will be described below.

[Example 1] Diameter 70 mm, length 250 m
Fig. 1 shows two compressors of 5m type zeolite packed at a density of 0.8 in an adsorption column of m and a helical compressor (shown in Fig. 4 (a)) capable of obtaining a flow rate of 42L / min.
Connect and operate like the flow sheet of. As for the soundproofing of the equipment, the equipment is equipped with an exhaust silencer and a double soundproof housing. The equipment is an anechoic chamber, 1 m in front and 1/2 the height of the equipment.
Measure at the height of.

[Embodiment 2] A helical compressor using the grooved blade shown in FIG. 4B is connected and operated as shown in the flow sheet of FIG. Other conditions are the same as those in the first embodiment.

[Embodiment 3] As shown in FIG.
A helical compressor using a magnetic fluid (manufactured by Sigma High Chemical Co., Ltd.) in the gap between the helical blade and the helical groove is connected and operated as shown in the flow sheet of FIG. The other conditions are the same as in Example 1.

Comparative Example 1 Diameter 90 mm, Length 400 m
As shown in the flow sheet of Fig. 1, connect two m-adsorption cylinders filled with 5A zeolite at a density of 0.8 and a piston-type air compressor capable of obtaining a flow rate of 70 L / min. And make it work. Other conditions are the same as those in the first embodiment.

[0034]

The results of the above examples are shown in Table 1. The performance difference between Example 1 and Comparative Example 1 is very large, and by adapting the helical blade type compressor, which has little pressure fluctuation, to the oxygen concentrator, the yield of the adsorption column is significantly improved and the noise reduction effect is also obtained. It turns out to be big. As a result, the size and weight of the device itself can be reduced. In addition, in the second and third embodiments, the sealing performance of the helical blade type compressor is improved, and as a result, the reduction of power consumption is further improved.

[0035]

[Table 1]

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram of a two-cylinder oxygen concentrator of the present invention.

FIG. 2 is a schematic structure of an air compressor used in the oxygen concentrator of the present invention.

FIG. 3 is a partial cross-sectional view showing the relationship between the structures of the helical blade and the helical groove of the air compressor used in the oxygen concentrator of the present invention.

4 is a partial cross-sectional view showing a structure of a helical blade and a helical groove of the air compressor shown in FIG.

Continued front page    (72) Inventor Toshio Motoki             3-4-1 Mihara, Ibaraki-shi, Osaka Teijin Limited             Inside the Osaka Research Center (72) Inventor Hideki Kobayashi             2-1-1 Uchisaiwaicho, Chiyoda-ku, Tokyo             People F-term (reference) 4D012 CA05 CB16 CD07 CE01 CF05                       CK10                 4G042 BA15 BA29 BB02 BC04

Claims (4)

[Claims] 1. At least one adsorption cylinder filled with an adsorbent capable of selectively adsorbing nitrogen rather than oxygen, and an air compressor for supplying pressure to and / or exhausting air under reduced pressure to the adsorption cylinder. A pressure fluctuation type oxygen concentrator, wherein the air compressor is a helical compressor provided with a helical blade. 2. The oxygen concentrator according to claim 1, wherein at least one groove is provided on a side surface of the helical blade. 3. The oxygen concentrator according to claim 1, wherein the air compressor is one in which a gap between a helical groove and a helical blade provided on a rotor of a helical compressor is filled with a magnetic fluid. . 4. The oxygen concentrator according to claim 1, wherein the electric motor that drives the air compressor is a brushless electric motor that is driven by a DC power supply, and includes an inverter.