JPH0790135B2 - Gas concentrator with automatic switching device depending on power frequency - Google Patents

Description

TECHNICAL FIELD The present invention relates to an improvement of a gas concentrator that separates a gas by a pressure swing adsorption (PSA) method.

(Prior art) PSA is one of the methods to separate and concentrate gas using air as a raw material.
There is a law. This PSA method uses multiple adsorption towers filled with an adsorbent that tends to selectively adsorb a specific gas mainly of the feed air that is supplied under pressure. The gas is discharged and used as a product gas to separate and concentrate the gas. In addition, decompressing the adsorbent that once adsorbed gas, etc.
Purified and regenerated to prepare for the next cycle.

It is known that when the gas is separated and concentrated by the PSA method, the gas concentration efficiency differs depending on the cycle switching time (adsorption time / desorption time). (See, for example, "Composition of Pressure Swing Adsorption Technology" published by Japan Society of Industrial Technology).

General Power in Japan (purchased power), the frequency by region has 50H _Z and 60H _Z, the ability of the compressor directly connected to the feed air gas concentrator by PSA method the pressure supplied motor, the power supply voltage It is generally known that even if the frequency is constant, if the frequency is different, the rotation speed and torque of the motor are different, so that the ability, that is, the discharge air amount also changes.

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

(Problems to be Solved by the Invention) In the case of an oxygen concentrator by the PSA method, the following table shows an example of the relationship between the concentration of product gas to be discharged (volume ratio, the same applies hereinafter) and the oxygen flow rate. Table 1, in which the power supply frequency is adjusted to the optimum condition (orifice and switching operation pressure) at 60H _Z,
Table 2, under the conditions adjusted in the above 60H _Z, the case where only the power frequency 50H _Z. Table 3 shows the above 60
And those adjusted in H _Z power frequency 50H _Z is obtained by newly adjusted only orifices.

The Table 4 is obtained by adjusting the newly optimal conditions (orifice and switching operation pressure) at mains frequency 50H _Z.

In addition, the switching of the adsorption tower in each cycle is performed with the operating pressure kept constant.

As is clear from this table, the oxygen gas concentration discharged by the oxygen concentrator differs depending on the power supply frequency. Therefore, in order to improve the difference, the one in which the orifice cross-sectional area of the purge gas ventilation passage is arbitrarily selected is described in the above publication. It is the invention disclosed in.

The present invention automatically detects that the power frequency becomes 50H _Z or 60H _Z, a pore cross section with selectively switching of said orifice, by switching simultaneously the switching time in each cycle, PSA If the gas concentrator is a medical oxygen concentrator, most of its distribution form is so-called rental, and the same device is used as a power supply frequency. The purpose is to be able to automatically select the optimum conditions even when rented in different areas.

(Means for Solving the Problem) The present invention has a plurality of adsorption towers filled with an adsorbent that selectively adsorbs mainly a specific easily adsorbable gas of the feed air to be supplied, and these adsorption towers are alternately arranged. In a gas concentrator by the pressure fluctuation adsorption method, in which a specific difficult-to-adsorb gas is concentrated to obtain a product gas, a change in the power frequency of the AC power supply to the compressor for driving the compressor from the AC power supply The control circuit detects and selectively switches the pore cross-sectional area of the orifice attached to the purge gas passage for purifying and regenerating the adsorbent, and also selectively switches the switching time for alternately switching the adsorption tower. A gas concentrator with an automatic switching device according to the power supply frequency characterized by being configured.

(Operation) An example embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a schematic flow system diagram of an automatic power supply frequency switching device of the present invention, FIG. 2 is a block diagram of a control circuit, and FIG. 3 is a solenoid valve corresponding to a relay operated by a difference in power supply frequency. 6 is a time chart showing switching of orifices.

In FIG. 2, 16 is an IC for frequency discrimination (in this embodiment,
LM567) and the only relay 1 when the power supply frequency in the constant of 60H _Z of 23
It activates 7 (see Fig. 3), and the relay controls the following.

50 orifices attached to the purge gas ventilation passage
Selectively switching those different pore cross-sectional area of a H _Z for the 60H _Z (corresponds to switching of the orifice 1 and the orifice 2 of FIG. 3).

Wherein selectively switching the different times of a 50H _Z for the 60H _Z switching time in each cycle (t ₁ of FIG. 3, t ₂ and t
_{It corresponds to 1} ′, t ₂ ′. ).

The present invention operates as follows. Configuration power supply frequency of the gas concentrator detects whether a is either 60H _Z is 50H _Z are as follows.

In FIG. 2, the electronic control device IC detects the unique constant determined by the capacitor C having the constant 23 provided in the control circuit and the electric resistance R and the phase difference at each power supply frequency. Based on this detection result, the relay is driven and the contact of the relay operates the three-way solenoid valve to selectively switch the air passage of the orifice (three-way valve, orifices 1, 2 in FIG. 3).
See).

The constant relating to the switching time in each cycle of the control circuit is selectively switched. This switching time is constituted by an IC (LM4538, LM4077 in the embodiment described later) which is a flip-flop device, and switching of the 5-way valve is performed by driving 22 solid state relays. Since the constant for determining the switching time of the IC is determined by the capacitor C and the electric resistance R connected to the IC, the resistors R and R'are selected by the relay so as to have a desired switching time. The means for detecting the difference in power supply frequency can be detected by other methods regardless of the above configuration. For example, a method of detecting a difference in power supply frequency by passing through an electric filter circuit, a method of dividing the power supply frequency and detecting a difference in its cycle, or the like can be adopted.

(Embodiment) An embodiment of the present invention is an apparatus using oxygen gas as a product by the PSA method, which will be described below with reference to the drawings.

FIG. 1 is a system diagram showing a flow in which a safety device and an alarm device of a device according to the present invention, which implement the present invention, are omitted, and FIG. 2 is a block diagram of an electric system of a control circuit for controlling the device. It is a diagram.

In FIG. 1, reference numeral 1 denotes an AC power supply, which operates the compressor 3 to supply pressurized air to the adsorption tower 5 or 5'and also to the control circuit 10.

On the other hand, the adsorption tower on the side not supplying the raw material air is desorbed under reduced pressure to purify and regenerate the adsorbent. Reference numeral 15 is a unit for driving the control circuit 10 by obtaining a DC current from the AC power supply.

Numerals 5 and 5'are filled with a zeolite-based adsorbent that selectively adsorbs nitrogen. Oxygen gas and a small amount of argon gas which are difficult to be adsorbed are reduced to a desired pressure by a pressure reducing valve 11 via a buffer tank 9. The product gas outlet 14 is configured to take out the product gas. Further, 19 is a 5-way valve control signal for controlling the 5-way valve with different switching times when the power supply frequency is 50H _Z and 60H _Z , and 20 is the same as 50H _Z and 60H _Z , and switches the orifice to 6 or 6'3. Controlling the way valve 3
This is a one-way valve control signal.

In addition, 2 is a suction filter, 13 is a flow control valve and a flow meter,
8,8 'is a one-way valve, and 21 is a silencer.

More particularly in Figure 2, 16 is the power supply frequency 50H _Z
There a frequency discriminator for detecting whether 60H _Z, the phase in 50H _Z and 60H _Z as described in the previous section are different is detected by IC which was so as to drive the relay 17, this embodiment in those where the power frequency relay 17 only when the 60H _Z was made to operate. Its operating range is 58.5H _Z ~61.5H _Z
Is. Reference numeral 18 is a time switch for obtaining a five-way valve control signal 19 so that the adsorption tower has a different switching time in each cycle. 20 is a three-way valve control signal. The gas flow path switching valves used in this embodiment are a three-way valve and a five-way valve, and their schematic structural diagrams are as shown in FIGS. 4 and 5.

In FIG. 4 or 5, 24 is a drive coil, 25 is a spring, 26 is an iron core, and 27 is a spool. And the fourth
In the three-way valve shown in the figure, outlets 29 and 29 'are provided for the inlet 28, and in the five-way valve shown in FIG.
9,29 'and exhaust ports 30,30' are provided.

Next, the PSA when the rated discharge amount of the product gas is the same when the present invention is carried out and when the conventional technique is carried out.
Table 5 shows a comparison of the size of the adsorption tower of the oxygen concentrator and the same equipment by the method. (Product gas concentrations are 50H _Z and 60H _Z
Of the values driven by the power supply, it is the lower number) In the present embodiment, the adsorption tower was mainly filled with a zeolite-based adsorbent that selectively adsorbs nitrogen, and oxygen gas was discharged as a product gas.However, the present invention is not limited to this embodiment, and another adsorption It is also possible to use the agent to obtain another product gas. For example, it is also possible to fill an activated carbon-based adsorbent which mainly selectively adsorbs oxygen and to discharge nitrogen gas as a product gas. Also in the adsorption tower,
In addition to the adsorbent, filling a small amount of a hygroscopic agent is also effective in preventing deterioration of the adsorbent.

(Effect of the invention) In the gas concentrator by the PSA method, when the power supply frequency is different from 50H _Z or 60H _Z in the conventional technology, even if the power supply frequency of the device is inferior (generally 50H _Z ), it is desirable. Since it is necessary to obtain the performance of, the external appearance and the weight tended to increase.

Attempts have also been made to arbitrarily select the orifice according to the power supply frequency, but the switching time of each cycle was outside the scope.

By implementing the present invention, even when the power supply frequency is different from 50H _Z and 60H _Z , the difference is automatically detected and the orifice is selected, and the switching time of each cycle is also selected. The power supply frequency performance of the device can be further enhanced, resulting in the following effects.

With any of the above power supplies, the operating conditions (orifice and cycle switching time) of the device can be automatically kept optimal, so for example, nationwide rental or lease of the device for areas with different power supply frequencies Even the so-called lending business can operate efficiently.

Compared with the same device as the prior art, highly efficient gas concentration is possible even when the power supply frequency is different, so that it is possible to significantly reduce both the external dimensions and weight when the product discharge flow rate is the same. (In this embodiment, the external volume ratio is about 1/2, and the weight ratio is 1 / 1.3).

[Brief description of drawings]

FIG. 1 is a system diagram showing a flow of a gas concentrator by the PSA method suitable for carrying out the present invention, in which a safety device and an alarm device are omitted, and FIG. 2 is a block diagram of a control circuit of the gas concentrator, FIG. 3 is a time chart showing switching of an electromagnetic valve corresponding to a relay and an orifice, FIG. 4 is a schematic structural diagram of a 3-way valve, and FIG. 5 is a schematic structural diagram of a 5-way valve. 1 ... AC power supply 2 ... Suction filter 3 ... Compressor 4 ... 5-way valve 5,5 '... Adsorption tower 6,6' ... Orifice 7 ... 3-way valve 8, 8 '... 1-way valve 9 …… Buffer tank 10 …… Control circuit 11 …… Reducing valve 13 …… Flow control valve and flowmeter 14 …… Product gas outlet 15 …… DC power supply 16 …… Frequency discriminator 17 …… Relay 18 …… Time switching Device 19 …… 5-way valve control signal 20 …… 3-way valve control signal 21 …… Silencer 22 …… Solid state relay 23 …… CR constant 24 …… Drive coil 25 …… Spring 26 …… Iron core 27 …… Spool 28 …… Inlet 29,29 ′ …… Outlet 30,30 ′ …… Exhaust port

Claims (1)

[Claims] 1. A raw material air is compressed and pressurized by a compressor (3) driven by the electric power of an AC power source (1), and the compressed air is supplied to an adsorption tower (5) or another adsorption tower (5 '). do it,
It has a plurality of adsorption towers filled with an adsorbent that selectively adsorbs mainly a particular easily adsorbable gas of the raw material air, and these adsorption towers are alternately switched by a five-way valve (4) to achieve a specific difficulty. In a gas concentrator by a pressure fluctuation adsorption method for concentrating an adsorptive gas to obtain a product gas, a power supply for supplying power from the AC power supply (1) to the compressor (3) for driving the compressor (3). The power circuit frequency is detected by the control circuit (10) and the cross-sectional area of the pores of the orifice attached to the purge gas ventilation path for purifying and regenerating the adsorbent is selectively switched and the adsorption tower is switched alternately. A gas concentrator with an automatic switching device according to the power supply frequency, which is characterized by selectively switching the time.