JPH0544222U - Gas concentrator - Google Patents

Abstract

(57) [Abstract] [Purpose] In a gas concentrator using the pressure swing adsorption method (PSA method), the switching time for alternately switching the process of pressurizing supply of raw material air to the adsorption column and depressurizing exhaust, Automatically selected by changing the frequency of the AC power supply. A desired time is obtained by dividing the frequency of the AC power supply, and if the frequency of the AC power supply changes, the switching time also automatically changes to another desired time.

Description

[Detailed description of the device]

The present invention relates to an improvement of a gas concentrator that separates a gas by a pressure swing adsorption (Pressure Swing Adsorption on) method.

[0002]

[Prior Art]

 One of the methods for separating and concentrating gas using air as a raw material is the PSA method. In this PSA method, the feed air is pressurized and exhausted under constant pressure in an adsorption column filled with an adsorbent or the like that easily adsorbs a specific gas selectively from the feed air supplied under pressure. The gas is separated and concentrated by alternating the cycle and discharging a specific gas that is difficult to be adsorbed to produce a product gas.

In addition, the adsorbent or the like which has once adsorbed gas or the like is decompressed, and the adsorbent or the like is desorbed and regenerated to prepare for the next cycle. Further, a part of the product gas may be introduced as a purge gas into the adsorption column to purify the adsorbent.

The general power source (purchased power source) in Japan has a frequency of 50 Hz and 60 Hz depending on the region, and the ability of the compressor directly connected to the motor for pressurizing the feed air of the gas concentrator by the PSA method is the power source voltage. It is generally known that, even if is constant, if the frequency is different, the rotation speed and torque of the motor are different, so that its capacity, that is, the discharge air amount also changes.

In this way, when the capacity of the compressor changes depending on the power supply frequency, the flow rate of the purge gas can be arbitrarily selected in each region where the power supply frequency is different to improve the efficiency of the gas concentrator by the PSA method. Attempts have been made to improve. (See, for example, Japanese Utility Model Publication No. 62-739)

[0006]

When the flow rate of the product gas to be discharged is the same in the oxygen concentrator by the PSA method, the relationship between the concentration (volume ratio, the same below) and the PSA switching time is as follows. It looks like Table 1. Table 1 Discharge flow rate switching time Oxygen concentration Power supply frequency (liters / minute) (seconds) (%) (Hz) 3.0 14.40 95.2 60 3.0 14.40 85.5 50 3.0 3.0 17.28 94.8 50

Therefore, for example, even if the power supply frequency is adjusted to 60 Hz and the optimum switching time (14.40 seconds, oxygen concentration 95.2%) is adjusted, the power supply frequency is changed under the same conditions of the discharge flow rate and the switching time. When it was set to 50 Hz, there was a problem that the oxygen concentration dropped to 85.5%.

Further, when the power supply frequency was 50 Hz, an oxygen concentration of 94.8% could be obtained by adjusting to the optimum switching time (17.28 seconds) at this frequency. (See Table 1)

Conventionally, there has been a problem that when the oxygen concentrator is used, it has to be adjusted to conditions suitable for the power source frequency of each place of use each time.

[0010]

[Means for Solving the Problems]

 The present invention is characterized in that, in a gas concentrator including an oxygen concentrator by the PSA method, a switching time for alternately switching the above steps is automatically selected according to a change in power supply frequency. To do.

As is clear from Table 1 above, the frequency ratio between 50 Hz and 60 Hz is 1.2, and the cycle is 1.2 times 50 Hz to 60 Hz.

Further, the optimum switching time was 1.2 times for 50 Hz compared to 60 Hz. Therefore, paying attention to the difference in this cycle and associating the cycle with the switching time, the change in the power supply frequency was changed. On the other hand, the switching time is automatically selected.

[0013]

【Example】

 An embodiment of the present invention will be described below with reference to the drawings, but the present invention is not limited to this embodiment. FIG. 1 is a system diagram showing an outline of a gas concentrator according to the present invention, and FIG. 2 is a system diagram showing details of a switching timing signal generator of a control circuit 22.

In FIG. 1, reference numeral 10 is an AC power supply, which drives the compressor 14 and the five-way valve 18 and also serves as a power supply for operating the control circuit 22.

Reference numerals 24 and 25 are adsorption cylinders filled with an adsorbent or the like that selectively adsorbs the easily adsorbable gas of the raw material air. In this embodiment, two adsorption cylinders were used. The number of cylinders may be one, or a plurality of cylinders may be two or more, and the operation effect obtained by automatically switching the switching time according to the power supply frequency does not change.

Reference numeral 28 is a product gas tank, and check valves 26 and 27 are one-way valves that prevent the product gas from flowing backward toward the adsorption cylinder.

The pressure reducing valve 30 and the flow meter 32 set the product gas in the product gas tank 28 to a desired pressure and flow rate.

In FIG. 2, reference numeral 36 is an AC power supply signal inlet, and this AC power supply signal is half-wave rectified by a rectifying and shaping circuit 38 to be shaped into a pulse signal, and a clock signal of a frequency dividing IC 44 is obtained. It is a thing.

When a pulse signal is obtained by half-wave rectifying the AC signal, the interval between the pulse signals becomes equal to the cycle of the power supply frequency. For example, when the power supply frequency is 50 Hz, the interval between the pulse signals is 0.02 seconds.

The frequency dividing IC 44 is for further frequency ^{dividing the} clock signal, and the frequency division is ½ ⁿ (n is a positive integer). That is, it becomes 2 ⁿ times the power supply cycle.

For example, when the power supply frequency is 50 Hz, if n = 9, that is, if the frequency is divided by 9, then (1/50) × 2 ⁹ = 10.24 (seconds), and the power supply frequency becomes 60 Hz in this state. Then, (1/60) × 2 ⁹ = 8.53 (seconds).

There is an IC suitable for performing such frequency division, and one example thereof is TC4040 BP (trade name), and this IC was also used in this embodiment.

When the power supply frequency is 50 Hz, the switching time is 10.24 seconds when n = 9, but is 20.48 seconds when n = 10, and the switching time is adjusted too coarsely.

In the above-mentioned IC, the frequency division outputs are from Q ₁ to Q ₁₂ , and each frequency division output of 1/2 to 1/2 ¹² is obtained. By the setting means 42 and the AND circuit 46, it is possible to obtain an arbitrary frequency division ratio suitable for the gas concentrator by the PSA method.

As the switching time setting means 42, eight DIP switches (dual in-line package switches) are used in this embodiment. With such a configuration, when the power supply frequency is 50 Hz, the switching time before and after 10.24 seconds is 9. It is 92 seconds and 10.56 seconds, and the desired switching time can be obtained. The switching time setting means 42 is not limited to the eight DIP switches of this embodiment, and may be another means. For example, using a plurality of switching means.

As described above, in the present embodiment, as the means for obtaining the switching time, the desired time is obtained by dividing the AC frequency, but as another method, the pulse obtained from the AC power supply can be used. Even if the number is counted and the desired switching time is obtained with an arbitrary counted number, the action and effect are the same.

FIG. 3 is a system diagram showing another embodiment of means for obtaining the switching time. In this figure, the frequency discriminator 50 is a frequency discriminator for discriminating whether the power supply frequency is 50 Hz or 60 Hz. Then, the time constant that determines the time of the timer 52 is selected to the value of the process switching time required for 50 Hz or 60 Hz, respectively, by the signal obtained by this frequency discrimination.

In the present embodiment, the switching time was a desired time automatically selected according to the frequency of the AC power source, but the performance of the gas concentrator according to the present invention (mainly the concentration of the product gas) Changes slightly depending on the discharge flow rate and discharge pressure of the product gas other than the switching time. Therefore, a better effect can be expected by detecting the values of these discharge flow rates and discharge pressures with a sensor and appropriately increasing or decreasing the switching time in consideration of these factors in the switching time.

In the present embodiment, the adsorption column is mainly filled with a zeolite-based adsorbent that selectively adsorbs nitrogen gas, and oxygen gas is discharged as a product gas. Not limited to this, it is possible to obtain another product gas by using another adsorbent.

For example, it is possible to fill an activated carbon-based adsorbent that mainly selectively adsorbs oxygen gas and discharge nitrogen gas as a product gas. It is also effective to prevent the deterioration of the adsorbent by filling a small amount of the hygroscopic agent in addition to the adsorbent in the adsorption column.

[0031]

[Effects of the Invention] By implementing the present invention, even in areas where the power supply frequency is different from 50 Hz and 60 Hz, the gas concentrator is switched to each frequency by the internal circuit. There is no need to distinguish and use the equipment for that frequency. When the equipment is a medical oxygen concentrator, there are many so-called rental and lease lending systems, but even if the equipment is rented or leased nationwide for areas with different power frequencies, the You can operate efficiently without being aware of it.

[Submission date] February 29, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0006

[Correction method] Change

[Correction content]

[0006]

[Problems to be solved by the device]

 In the oxygen concentrator by the PSA method, when the flow rate of the discharged product gas is the same, the relationship between the concentration (volume ratio, the same below) and the PSA switching time is as shown in Table 1 below.

[Table 1] Discharge flow rate Switching time Oxygen concentration Power supply frequency (liter / minute) (second) (%) (Hz) 3.0 14.40 95.2 60 3.0 14.40 85.5 50 3.0 3.0 17 .28 94.8 50

[Submission date] October 30, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] 0001

[Correction method] Change

[Correction content]

[0001]

[Industrial applications]

The present invention relates to an improvement of a gas concentrator that separates gas by a pressure swing adsorption method (hereinafter referred to as PSA). An example of its application is a medical oxygen concentrator.

[Procedure Amendment 2]

[Document name to be amended] Statement

[Name of item to be corrected] 0029

[Correction method] Change

[Correction content]

[0029] In this embodiment, by filling the adsorbent of zeolite which selectively adsorbs primarily nitrogen gas adsorption cylinder, an oxygen gas as a product gas has been configured to output ejection, the present actual施例Not limited to this, it is possible to obtain another product gas by using another adsorbent.

[Brief description of drawings]

FIG. 1 is a system diagram showing an outline of a gas concentrator by a PSA method with an automatic switching device.

FIG. 2 is a system diagram showing details of a switching timing signal generator of the control circuit.

FIG. 3 is a system diagram showing another embodiment of means for obtaining a switching time.

[Explanation of symbols]

 10 AC power supply 12 Filter 14 Compressor 16 Silencer 18 Five-way valve 20 Control signal 21 DC power supply 22 Control circuit 24 Adsorption cylinder A 25 Adsorption cylinder B 26 Check valve A 27 Check valve B 28 Product gas tank 30 Pressure reducing valve 32 Flow meter 34 Product gas Outlet 36 AC power supply signal inlet 38 Rectification shaping circuit 40 Timing circuit 42 Switching time setting means 44 Dividing IC 46 AND circuit 48 Switching timing signal 50 Frequency discriminator 52 Timer 54 Time constant switching signal

Claims (5)

[Scope of utility model registration request] 1. An adsorbent having at least one adsorption column filled with an adsorbent or the like that selectively adsorbs an easily adsorbable gas of the raw material air, and supplying the raw material air under pressure to the adsorption column to facilitate adsorption. Pressure fluctuation to obtain product gas by alternately switching the adsorption step of adsorbing gas and concentrating the hard-to-adsorb gas, and the desorption step of depressurizing the adsorption column to desorb and regenerate the adsorbent etc. A gas concentrator according to the adsorption method, wherein a switching time for alternating the above steps is a desired time automatically selected according to the frequency of the AC power supply. 2. A means for obtaining a switching time for alternately switching the process of pressurizing supply and depressurizing exhaust of the raw material air to the adsorption column, divides the frequency of the AC power supply to obtain a desired time. The gas concentrator according to claim 1, which is obtained. 3. A means for obtaining a switching time for alternately switching the process of pressurizing supply and depressurizing exhaust of the raw material air to the adsorption column, counts the number of pulses obtained from an AC power source, and arbitrarily The gas concentrator according to claim 1, wherein a desired time is obtained by the number of counts. 4. The means for obtaining a switching time for alternately switching the process of pressurizing supply and depressurizing exhaust of the raw material air to the adsorption cylinder is based on a signal obtained from the frequency of the AC power source by the frequency discriminating means. 2. The gas concentrator according to claim 1, wherein the time constant of the timer means is selected to obtain a desired time. 5. The value of the discharge flow rate and / or discharge pressure of the gas concentrator is used as a means for obtaining a switching time for alternately switching the process of pressurizing supply and depressurizing exhaust of the raw material air to the adsorption column. 3. The switching time is set to a desired time by adding an element obtained based on
The gas concentrator according to claim 3 or claim 4.