JP2008284442A - Oxygen concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact type oxygen concentrator wherein an adsorbent is prevented from deteriorating by surely removing moisture contained in air. <P>SOLUTION: The oxygen concentrator 1 comprises at least two adsorption cylinders 3, 4 packed with adsorbent 31, 41 selectively adsorbing nitrogen, a compressor 2 for compressing air to be fed to the adsorption cylinders 3, 4 and a switching means 6 connected between the compressor 2 and the adsorption cylinders 3, 4 for feeding the air compressed by the compressor 2 to either one of the adsorption cylinders 3, 4. A drain pot 7 is connected between the compressor 2 and the switching means 6, and a control means 8 for controlling the pressure inside the drain pot 7 is provided for the purpose of removing moisture contained in the compressed air compressed by the compressor 2 in the drain pot 7. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oxygen concentrator applied to an ozone generator, a medical oxygen concentrator, and the like.

  The oxygen concentrator is an apparatus that concentrates oxygen in the air using several adsorption cylinders filled with an adsorbent such as zeolite that selectively adsorbs nitrogen (see, for example, Patent Document 1).

  As such an oxygen concentrator, for example, one of two adsorption cylinders is adsorbed and the other is desorbed and regenerated, and oxygen is continuously produced by switching between adsorption and desorption at each adsorption cylinder every predetermined time. Such a PSA oxygen concentrator is known.

JP 2004-275493 A

  Here, the adsorbent mainly repeats adsorption and desorption of nitrogen, but has the property of simultaneously adsorbing moisture and other gases in the air. In particular, water is strongly adsorbed by the adsorbent and is the primary problem that degrades the performance of the adsorbent.

  As a countermeasure, a drain pot or a hygroscopic agent is placed upstream of the adsorbent to remove moisture in the air. However, a large amount of hygroscopic agent is required to perform sufficient dehumidification, and the oxygen concentrator is large. It will become.

  In addition, there are measures such as packing a large amount of adsorbent in anticipation of deterioration due to moisture, but there is a problem that the size of the adsorption cylinder and oxygen concentrator increases.

  Accordingly, an object of the present invention is to provide an oxygen concentrator that solves the above-mentioned problems, can reliably remove moisture in the air as a raw material to prevent deterioration of the adsorbent, and can be made compact. There is to do.

  In order to achieve the above object, the present invention provides at least two adsorption cylinders filled with an adsorbent that selectively adsorbs nitrogen, a compressor for compressing air supplied to the adsorption cylinder, and the compressor, In the oxygen concentrator provided with switching means connected between the adsorption cylinders and supplying compressed air of the compressor to any of the adsorption cylinders, a drain pot is connected between the compressor and the switching means, An adjusting means for adjusting the pressure in the drain pot is provided in order to remove moisture in the compressed air compressed by the compressor with the drain pot.

  Preferably, the adjusting means includes an orifice or a regulator provided between the drain pot and the adsorption cylinder.

  Preferably, the adjusting means includes an orifice or a regulator provided between the adsorption cylinder and a storage means for storing high-concentration oxygen concentrated in the adsorption cylinder.

  Preferably, the adsorbing cylinder is filled with a hygroscopic agent, and the hygroscopic agent is disposed closer to the compressor than the adsorbent.

  Preferably, the drain pot is provided with cooling means for cooling the compressed air in the drain pot to condense moisture.

  According to the present invention, it is possible to reliably remove moisture in the air as a raw material and prevent deterioration of the adsorbent, and to exhibit an excellent effect that the oxygen concentrator can be made compact. is there.

  Hereinafter, a preferred embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  The oxygen concentrator of this embodiment is a PSA oxygen concentrator (PSA device) that concentrates oxygen by a PSA (Pressure Swing Adsorption) method, and is applied to, for example, an ozone generator or a medical oxygen concentrator.

  The schematic structure of the oxygen concentrator of this embodiment will be described based on FIG.

As shown in FIG. 1, an oxygen concentrator 1 of this embodiment includes a compressor 2 for compressing air and an adsorbent (hereinafter referred to as N ₂ adsorbent) 31 that selectively adsorbs nitrogen from the compressed air. , 41 filled with at least two (two in the illustrated example) adsorption cylinders 3, 4 and storage means for storing high-concentration oxygen concentrated in the adsorption cylinders 3, 4 (hereinafter referred to as O ₂ buffer tank) ) 5, a switching means 6 connected between the compressor 2 and the adsorption cylinders 3, 4 for supplying the compressed air of the compressor 2 to any of the adsorption cylinders 3, 4, and between the compressor 2 and the switching means 6 The connected drain pot 7 and adjusting means 8 for adjusting the pressure in the drain pot 7 (hereinafter referred to as the drain pot internal pressure) in order to remove the moisture in the compressed air compressed by the compressor 2 with the drain pot 7. Prepare.

  The compressor 2 may be a positive displacement compressor, for example, and is an electric diaphragm compressor in the illustrated example. The compressor 2 is connected to the drain pot 7 via the discharge pipe 10. The compressor is not limited to this, and may be a non-volumetric type.

  The drain pot 7 condenses moisture in the compressed air introduced from the discharge pipe 10 and separates the condensed water from the compressed air and stores the condensed water in the drain pot 7. The drain pot 7 has a valve connected to an external outlet (not shown) so that water stored in the drain pot 7 can be removed as appropriate. The drain pot 7 is connected to a branch pipe 11 for supplying dehumidified compressed air to the adsorption cylinders 3 and 4 respectively.

  In the present embodiment, the branch pipe 11 between the adsorption cylinders 3 and 4 and the drain pot 7 is provided with an orifice 81 (hereinafter referred to as an upstream orifice) that constitutes the adjusting means 8. The upstream side orifice 81 restricts the branch pipe 11 through which the compressed air passes in order to maintain the drain pot internal pressure (discharge pressure of the compressor 2) higher than the pressure in the adsorption cylinders 3 and 4.

  The branch pipe 11 branches into two at the downstream branch portion of the upstream orifice 81 and is connected to the switching means 6.

  In the illustrated example, the switching means 6 includes two three-way switching valves 61 and 62 provided corresponding to the two adsorption cylinders 3 and 4, and each of the three-way switching valves 61 and 62 includes the branch pipe 11 and the drain pot 7. Are connected to the compressor 2 respectively.

  The three-way switching valves 61 and 62 are connected to the adsorption cylinders 3 and 4 through the compressed air introduction pipe 12 and are connected to the silencer 14 through the exhaust pipe 13. The three-way switching valves 61 and 62 include an adsorption position where the adsorption cylinders 3 and 4 (compressed air introduction pipe 12) communicate with the compressor 2 (branch pipe 11), and the adsorption cylinders 3 and 4 (compressed air introduction pipe 12) and a silencer. 14 (exhaust pipe 13) can be switched between the detachment position and the communication position.

  These three-way switching valves 61 and 62 are connected to a controller or the like (not shown), and are PSA controlled (open / close control) in conjunction with each other.

The adsorption cylinders 3 and 4 are respectively connected to a compressed air introduction pipe 12 and an oxygen extraction pipe 15 connected to the O ₂ buffer tank 5. The adsorption cylinders 3 and 4 are filled with N ₂ adsorbents 31 and 41 and hygroscopic agents 32 and 42. The N ₂ adsorbents 31 and 41 and the hygroscopic agents 32 and 42 are arranged such that the hygroscopic agents 32 and 42 are on the compressor side, and the N ₂ adsorbents 31 and 41 are on the O ₂ buffer tank side. The N ₂ adsorbents 31 and 41 are made of, for example, synthetic zirconium, and the hygroscopic agents 32 and 42 are made of, for example, silica gel.

In the present embodiment, downstream orifices 16 and 16 for pressure adjustment are provided in the oxygen extraction pipes 15 between the respective adsorption cylinders 3 and 4 and the O ₂ buffer tank 5. These downstream orifices 16 and 16 respectively throttle the oxygen extraction pipe 15 through which high-concentration oxygen passes so that the pressure in the O ₂ buffer tank 5 is almost atmospheric pressure. A regulator may be provided in place of the downstream orifices 16 and 16.

The oxygen take-out pipes 15 and 15 are connected together at the gathering portion and connected to the O ₂ buffer tank 5.

The O ₂ buffer tank 5 is connected to an ozone generator (not shown) or the like via a tank pipe 17, and the tank pipe 17 is provided with a regulator 18 for adjusting the flow rate or pressure.

  Next, the operation of the oxygen concentrator 1 according to the present embodiment will be described based on FIG.

In the present embodiment, the N ₂ adsorbent 31 of one adsorption cylinder 3 is adsorbed with nitrogen in compressed air to concentrate oxygen (adsorption process), and the other adsorption cylinder 4 is used to nitrogen the N ₂ adsorbent 41. The adsorption cylinder 4 is desorbed to regenerate (regeneration process), and the adsorption cylinders 3 and 4 for nitrogen adsorption and the adsorption cylinders 3 and 4 for nitrogen desorption are alternately switched at predetermined intervals to continuously To produce high concentration oxygen. Moreover, in this embodiment, when switching an adsorption | suction process and a regeneration process, the pressure equalization process for making the pressure in the two adsorption cylinders 3 and 4 mutually equal is performed.

  Below, these adsorption processes, a regeneration process, and a pressure equalization process are explained.

  First, the adsorption process will be described using the adsorption cylinder 3 on the left side of FIG.

[Adsorption process]
The raw material air sucked into the compressor 2 from the outside is increased by the compressor 2 to a predetermined discharge pressure. The pressurized compressed air (pressurized air) passes through the drain pot 7, and condensed water is collected in the drain pot 7 and dehumidified (dehydrated). The compressed air dehumidified in the drain pot 7 is lowered to a desired adsorption pressure (operating pressure) at the upstream orifice 81 and then introduced into the adsorption cylinder 3 by the three-way switching valve 61 set at the adsorption position. .

The compressed air introduced into the adsorption cylinder 3 is further dehumidified by the moisture absorbent 32 filled in the adsorption cylinder 3, and then nitrogen is adsorbed by the N ₂ adsorbent 31 in the adsorption cylinder 3. This nitrogen adsorption generates high-concentration oxygen, which is stored in the O ₂ buffer tank 5 through the downstream orifice 16.

  Next, the regeneration process will be described using the adsorption cylinder 4 on the right side of FIG.

[Regeneration process]
In the regeneration process, the three-way switching valve 62 corresponding to the right adsorption cylinder 4 is switched to the desorption position, and high-concentration oxygen flows in the adsorption cylinder 4 in the direction opposite to the flow of compressed air in the adsorption process.

That is, high-concentration oxygen dried from the other adsorption cylinder 3 or the O ₂ buffer tank 5 in the adsorption process flows into the adsorption cylinder 4 through the oxygen take-out pipe 15 and the downstream orifice 16, and passes through the adsorption cylinder 4. The air passes through in the opposite direction to the adsorption step, and is exhausted out of the system through the compressed air introduction pipe 12, the three-way switching valve 62 at the desorption position, the exhaust pipe 13, and the silencer 14.

When the high-concentration oxygen is flowing through the adsorption column 4, and the moisture adsorbed component adsorbed on the N ₂ adsorption agent 41 (nitrogen) in the moisture absorbent 42 is desorbed, N ₂ adsorbent 41 and the moisture absorbent 42 Is played.

  Next, the pressure equalizing process will be described.

[Pressure equalization process]
The pressure equalization process is performed when switching between the adsorption process and the regeneration process. In the pressure equalization process, the flow paths of the three-way switching valves 61 and 62 are switched (for example, both the three-way switching valves 61 and 62 are switched to the detaching position), and the adsorption cylinder 3 and the adsorption cylinder 4 are connected to each other to absorb them. The pressure in the cylinders 3 and 4 is averaged and high concentration oxygen is recovered. After the pressure in the adsorption cylinders 3 and 4 is averaged, the flow paths of the three-way switching valves 61 and 62 are switched, and the adsorption cylinder 3 that has been performing the adsorption process is used as a regeneration process, and the adsorption cylinder 4 that is performing the regeneration process is replaced with Used in the adsorption process.

  As described above, by switching the three-way switching valves 61 and 62, the adsorption, pressure equalization, and regeneration operations of the adsorption cylinders 3 and 4 are repeated to continuously produce high-concentration oxygen gas. After using the oxygen concentrator 1, the water accumulated in the drain pot 7 is exhausted and dried, and the operation is terminated.

  Here, in this embodiment, the adjusting means 8 (upstream side orifice 81) is disposed downstream of the drain pot 7 so as to increase the dehumidifying capacity of the drain pot 7.

  That is, moisture contained in the air is more likely to condense (condensate) as the temperature of the air is lower and the pressure of the air is higher. Therefore, the higher the drain pot internal pressure, the higher the dehumidifying capacity of the drain pot 7.

On the other hand, the pressure in the adsorption cylinders 3 and 4 is determined by adsorption conditions (for example, the amount and density of the N ₂ adsorbents 31 and 41), the oxygen flow rate supplied by the oxygen concentrator 1, and the like.

  Therefore, in the present embodiment, the upstream side orifice 81 is provided between the drain pot 7 and the adsorption cylinders 3 and 4 to increase the discharge pressure of the compressor 2, thereby maintaining the inside of the adsorption cylinders 3 and 4 at a desired adsorption pressure. At the same time, the drain pot internal pressure is kept higher than the adsorption pressure in the adsorption cylinders 3 and 4. The drain pot internal pressure is set according to the diameter of the upstream orifice 81 and the operating conditions of the compressor 2 (for example, the reciprocating speed in the case of a diaphragm compressor).

Thereby, the moisture in the compressed air of the raw material flowing into the adsorption cylinders 3 and 4 can be reliably removed to prevent the deterioration of the N ₂ adsorbents 31 and 41, and the oxygen concentrator 1 can be made compact. Can do.

  As described above, in the present embodiment, the adjusting means 8 (upstream orifice 81) is provided on the downstream side of the drain pot 7, and the drain pot 7 is pressurized to a pressure higher than that of the adsorption cylinders 3 and 4 during operation to condense moisture. By removing water efficiently with the drain pot 7, the effect of dehydration can be improved.

As a result, the amount of N ₂ adsorbents 31 and 41 that deteriorates decreases and the moisture to be removed by the hygroscopic agents 32 and 42 decreases. Therefore, the amount of the N ₂ adsorbents 31 and 41 and the hygroscopic agents 32 and 42 is reduced. It becomes possible to reduce, and the size of the oxygen concentrator 1 can be made more compact.

  Next, the relationship between the pressure in the drain pot 7 and the amount of moisture absorbent in the adsorption cylinders 3 and 4 will be described.

In order to prevent degradation of N ₂ adsorbents 31 and 41, it is necessary to dehumidify the moisture content in the air to zero before the N ₂ adsorbents 31 and 41.

  In the present embodiment, as described above, moisture is removed by the drain pot 7 and the hygroscopic agents 32 and 42. Specifically, the drain pot 7 collects moisture equal to or greater than the saturated vapor amount, and moisture (water vapor) that cannot be collected is collected by the moisture absorbents 32 and 42.

  From this, by determining the operating pressure (drain pot internal pressure) of the drain pot 7, it becomes possible to determine the necessary amounts of the hygroscopic agents 32 and 42.

  An example of the drain pot internal pressure and the amounts of the hygroscopic agents 32 and 42 will be described with reference to FIG.

  FIG. 2 shows the amount of saturated water vapor for each pressure (absolute pressure) when air at 25 ° C. and 40 ° C. flows in.

  As shown in FIG. 2, when the operating pressure in the drain pot 7 is 150 kPa, the compressed air can be dehumidified to 17.2 mg / L in the drain pot 7. The hygroscopic agents 32 and 42 necessary for removing excess water at this time are defined as, for example, the necessary hygroscopic agent amount 100 g.

  When the operating pressure in the drain pot 7 is 200 kPa, the compressed air can be dehumidified in the drain pot 7 to 12.8 mg / L. At 200 kPa, the hygroscopic agents 32 and 42 can be reduced to the required hygroscopic agent amount of 75 g.

  When the operating pressure in the drain pot 7 is 300 kPa, the compressed air can be dehumidified to 6.5 mg / L in the drain pot 7. At 300 kPa, the hygroscopic agents 32 and 42 can be reduced to the required hygroscopic agent amount of 50 g.

  As described above, in this embodiment, the amount of the moisture absorbents 32 and 42 can be minimized by determining the amount of the moisture absorbents 32 and 42 according to the drain pot internal pressure. 1 can be made compact.

That is, since moisture is easily adsorbed by the N ₂ adsorbents 31 and 41 and is not easily desorbed, it is desirable to completely dehumidify using the moisture absorbents 32 and 42. However, if all the moisture flowing into the N ₂ adsorbents 31 and 41 is to be removed using only the hygroscopic agents 32 and 42, a large amount of the hygroscopic agents 32 and 42 are required.

  Therefore, in the present embodiment, by operating the drain pot 7 at a high pressure, it is possible to remove moisture in the air before entering the hygroscopic agents 32 and 42, and the necessary hygroscopic agent 32 is obtained. , 42 can be reduced and determined.

  Next, another embodiment will be described based on FIG.

  This embodiment is substantially the same as the above-described embodiment of FIG. 1 except for the configuration of the adjusting means. Accordingly, the same elements as those in the above-described embodiment are given the same reference numerals in the drawings, and detailed description thereof is omitted.

  In the oxygen concentrator 91 of the present embodiment, the operating pressure itself of the oxygen concentrator 91 (PSA device) using a pressure increasing mechanism (in the illustrated example, the downstream orifices 82 and 82) provided on the downstream side of the adsorption cylinders 3 and 4. Is increased to increase the amount of condensed water, and dewatering is performed in the drain pot 7.

In other words, the adjusting means 8 of the present embodiment includes the downstream orifices 82 and 82 provided in the oxygen extraction pipe 15 between the adsorption cylinders 3 and 4 and the O ₂ buffer tank 5. This downstream orifice 82 increases the pressure in the adsorption cylinder 3 (4) and the drain pot 7 during the adsorption process.

  For example, the diameter of the downstream orifices 82 and 82 is smaller than that of the downstream orifice 16 of FIG. 1 and the discharge pressure of the compressor 2 is increased, so that the drain pot 7 is substantially the same as that of the embodiment of FIG. Held at the same pressure.

  Also in this embodiment, the same effect as the embodiment of FIG. 1 can be obtained.

  In addition, this invention is not limited to the above-mentioned embodiment, Various modifications and application examples can be considered.

  For example, in the above-described embodiment, the orifice is used as the adjusting unit. However, the present invention is not limited to this. For example, a regulator may be used. In the case of using a regulator, a means for detecting the humidity of the air sucked into the compressor 2 is provided, and the higher the humidity detected by the means, the higher the set pressure of the regulator (smaller the throttle) can be considered.

  In order to further increase the dehumidifying capacity of the drain pot 7, it is conceivable to provide a cooling means for the drain pot 7. That is, when the discharge pressure of the compressor 2 rises and the compressor 2 generates heat and the temperature of the compressed air rises, there is a problem that the saturated water vapor amount increases. Therefore, it is possible to cool the drain pot 7 and make the temperature constant. . Further, it is possible to further dehumidify by controlling the operating temperature to be lower. As cooling means, means such as a heat radiating fin, an air cooling fan, and a heat pipe are conceivable.

FIG. 1 is a schematic configuration diagram of an oxygen concentrator according to an embodiment of the present invention. FIG. 2 is a diagram for explaining the relationship between the pressure in the drain pot and the amount of the hygroscopic agent. FIG. 3 is a schematic configuration diagram of an oxygen concentrator according to another embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oxygen concentrator 2 Compressor 3, 4 Adsorption cylinder 6 Switching means 7 Drain pot 8 Adjustment means 31, 41 Adsorbent 61, 62 Three-way switching valve 81 Upstream orifice

Claims (5)

At least two adsorption cylinders filled with an adsorbent that selectively adsorbs nitrogen, a compressor for compressing air supplied to the adsorption cylinder, and the compressor connected between the compressor and the adsorption cylinder In an oxygen concentrator provided with switching means for supplying the compressed air of
A drain pot is connected between the compressor and the switching means, and an adjusting means for adjusting the pressure in the drain pot is provided to remove moisture in the compressed air compressed by the compressor with the drain pot. An oxygen concentrator characterized by that.   The oxygen concentrator according to claim 1, wherein the adjusting means comprises an orifice or a regulator provided between the drain pot and the adsorption cylinder.   2. The oxygen concentrator according to claim 1, wherein the adjusting means comprises an orifice or a regulator provided between the adsorption cylinder and a storage means for storing high-concentration oxygen concentrated in the adsorption cylinder.   The oxygen concentrator according to any one of claims 1 to 3, wherein the adsorption cylinder is filled with a hygroscopic agent, and the hygroscopic agent is disposed closer to the compressor than the adsorbent.   The oxygen concentrator according to any one of claims 1 to 4, wherein the drain pot is provided with cooling means for cooling the compressed air in the drain pot to condense moisture.

Images