JP2011156530A - Air compressor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gas separation apparatus from which compressed air from a compressor is not emitted uselessly in unload operation. <P>SOLUTION: The gas separation apparatus 11 has an adsorption tank 17A or 17B to which the compressed air is supplied from the compressor 15 and an oxygen molecule is adsorbed on an adsorbent in the adsorption tank 17A or 17B to produce nitrogen gas. The compressor 15 is operated acceleratively for a predetermined time according to a pressure change of an air tank 40, which change is controlled by an inverter circuit 57, the amount of the product gas to be used or a pressure change of the adsorption tank 17A or 17B when an adsorption step is carried out. When the pressure of the air tank 40 is sufficiently high, the amount of the product gas to be used is small or the pressure of the adsorption tank 17A or 17B is raised sufficiently, the rotation of a motor 39 is decelerated suddenly. As a result, the compressed air from the compressor 15 is prevented from being emitted uselessly. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a PSA type (Pressure Swing Adsorption) gas separation device, and more particularly to a gas separation device configured to increase the operation efficiency of a compressor in accordance with the use state of compressed air from the compressor.

  In general, a PSA type gas separation apparatus separates air into nitrogen and oxygen using an adsorbent composed of molecular sieve carbon, zeolite, etc., and takes out one of them as a product gas for use.

  For this reason, for example, in a PSA type gas separation device that extracts nitrogen gas, (1) an adsorption step in which compressed air from a compressor is introduced into an adsorption tank filled with an adsorbent to adsorb oxygen molecules to the adsorbent; (2) The extraction step of taking out nitrogen separated and generated by the adsorbent, and (3) the regeneration step of releasing the inside of the adsorption tank to the atmosphere or reducing the pressure by a vacuum pump to regenerate the adsorbent are repeated. That is, in the extraction process, nitrogen in the adsorption tank is extracted outside, and in the regeneration process, the adsorbed oxygen is desorbed to prepare for the next adsorption process.

  Moreover, in an apparatus having a pair of adsorption tanks, the pressure equalizing process is performed after the extraction process is completed in one adsorption tank and the regeneration process is completed in the other adsorption tank. In this (4) pressure equalization process, both adsorption tanks are communicated with each other, and the gas remaining in the adsorption tank after the extraction process is supplied to the adsorption tank in the regeneration process to achieve pressure equalization, thereby producing a higher purity product gas. Is generated.

  However, in the gas separation device, nitrogen is separated and generated by repeating the steps (1) to (4). However, compressed air at a predetermined pressure is stored in an air tank with a constant rotation speed of the compressor. The compressed air in the air tank is supplied to the adsorption tank during the adsorption process. The compressor switches to the unload operation when the pressure of the air tank reaches the upper limit pressure, but the rotation speed of the compressor driving motor remains constant.

  For this reason, the conventional gas separation device is driven at a constant rotational speed regardless of, for example, the use state of compressed air or the pressure of the air tank, and therefore exhausts wastefully even when the amount of compressed air used is reduced. Otherwise, the compressed air must be exhausted wastefully even though the air tank pressure is sufficient.

  Therefore, in a conventional gas separation device, for example, when used in an environment where the amount of compressed air used varies over time, the compressed air will continue to be exhausted, and the operating efficiency of the compressor cannot be increased. It was.

  Then, an object of this invention is to provide the gas separation apparatus which solved the said subject.

  In order to solve the above problems, the present invention has the following features.

  The invention described in claim 1 is a gas separation device that supplies compressed air from a compressor to an adsorption tank filled with an adsorbent and pressurizes the inside of the adsorption tank, and detects a use state of the compressed air from the compressor. It is equipped with a rotation control means that decelerates the motor speed at a predetermined rate when the amount of compressed air detected by the detection means is less than or equal to a predetermined value, thereby preventing the air compressed by the compressor from being exhausted wastefully. Thus, it becomes possible to increase the operation efficiency of the compressor.

  According to a second aspect of the present invention, the detecting means comprises a pressure detector for detecting the pressure of the air tank of the compressor, and when the pressure of the air tank exceeds a predetermined value, the rotational speed of the motor is reduced at a predetermined rate. Thus, it is possible to prevent the air compressed by the compressor from being exhausted wastefully.

  According to a third aspect of the present invention, the detecting means comprises a flow meter for detecting the discharge flow rate of the product gas, and when the discharge flow rate of the product gas becomes a predetermined value or less, the rotational speed of the motor is reduced at a predetermined rate. It is possible to prevent the air compressed by the compressor from being exhausted wastefully.

  According to a fourth aspect of the present invention, the detecting means comprises a pressure detector for detecting the pressure in the adsorption tank, and when the pressure in the adsorption tank reaches the maximum usable pressure of the adsorbent, the rotation speed of the motor is set at a predetermined ratio. It is possible to prevent the air compressed by the compressor from being exhausted wastefully.

  As described above, according to the first aspect of the present invention, the gas separation device is configured to supply the compressed air from the compressor to the adsorption tank filled with the adsorbent and pressurize the inside of the adsorption tank. When the use amount of the compressed air detected by the detection means for detecting the use state is less than a predetermined value, the rotation control means for decelerating the motor speed at a predetermined rate is provided, so that the air compressed by the compressor is wasted. It is possible to increase the operating efficiency of the compressor by preventing the exhaust air from being exhausted.

  According to the second aspect of the present invention, since the detecting means comprises a pressure detector for detecting the pressure of the air tank of the compressor, when the pressure of the air tank exceeds a predetermined value, the rotational speed of the motor is set to a predetermined ratio. It is possible to prevent the air compressed by the compressor from being exhausted wastefully.

  According to the third aspect of the present invention, since the detecting means comprises a flow meter for detecting the discharge flow rate of the product gas, when the discharge flow rate of the product gas becomes a predetermined value or less, the rotational speed of the motor is increased at a predetermined rate. It can decelerate and it can prevent exhausting the air compressed with the compressor.

  According to the invention described in claim 4, since the detecting means comprises a pressure detector for detecting the pressure in the adsorption tank, when the pressure in the adsorption tank reaches the maximum usable pressure of the adsorbent, the rotation speed of the motor is reduced. It is possible to prevent the air compressed by the compressor from being exhausted wastefully by decelerating at a predetermined rate.

It is a schematic block diagram of one Example of the gas separation apparatus which becomes this invention. It is a block diagram which expands and shows the structure of a compressor. It is process drawing which shows the valve operation | movement of each process, and the pressure change of each adsorption tank. 5 is a flowchart of processing executed by an inverter circuit 57. It is a graph which shows the relationship between the amount of discharge air of a compressor, discharge pressure, and rotation speed. FIG. 10 is a configuration diagram showing a configuration of Modification 1; 7 is a flowchart showing processing of Modification 1 executed by an inverter circuit 57. FIG. 10 is a configuration diagram showing a configuration of Modification 2. 10 is a flowchart showing processing of Modification 2 performed by the inverter circuit 57.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram showing an embodiment of a gas separation apparatus according to the present invention.

As shown in FIG. 1, the gas separation device 11 is a PSA-type nitrogen generator that generates nitrogen as a product gas from compressed air, and starts to operate when a start signal is received. The control device 12 controls the valves V _{1 to} V ₁₁ of the refrigeration dryer 13, the air supply unit 16 having the compressor 15, the adsorption unit 17 and the storage unit 18. Further, the memory of the control device 12 stores data (see FIG. 5) indicating the relationship between the discharge pressure of the compressor 15 and the rotational speed, as will be described later.

  The compressed air generated by the compressor 15 is dehumidified by the refrigeration dryer 13 and is supplied to the adsorption unit 17 as dry and clean compressed air. The air supply unit 16 and the adsorption unit 17 are connected via a pipe line 19. Therefore, the compressed air dried by the dryer 13 passes through the pipe line 19 and the first and second adsorbents made of molecular sieve carbon are filled through the supply-side pipe lines 20 and 21 branched by the adsorption unit 17. It is supplied to the second adsorption tanks 17A and 17B. In addition, exhaust pipes 22 and 23 are branchedly connected to the pipes 20 and 21.

  FIG. 2 is an enlarged view showing the configuration of the compressor.

  As shown in FIG. 2, the compressor 15 is an air compressor called a package compressor, and a scroll compressor 38, a motor 39, and an air tank 40 are three-dimensionally and compactly arranged in a steel casing 37. It is stored. The motor 39 is provided with a rotation detector 46 including a resolver or a rotary encoder for detecting the number of rotations. The air tank 40 is provided with a pressure detector 47 that detects the pressure when the compressed air is filled.

  On the base 41 of the housing 37, a gantry 43 is fixed via an anti-vibration rubber 42. The motor 39 is fixed on the gantry 43 via a bracket 44, and the air tank 40 is fixed on the gantry 43 via a bracket 45.

  The compressor 38 is a combination of a fixed scroll and a turning scroll that is rotationally driven by a motor 39. The fixed scroll and the orbiting scroll have a plurality of partition walls formed in an involute curve or a spiral shape close to the involute curve. A crescent-shaped compression chamber is formed between the fixed scroll and the orbiting scroll partition wall, and the volume of the compression chamber near the center is smaller. Therefore, the air flowing into the compression chamber from the outer peripheral side is compressed while moving to the central portion along with the rotation of the orbiting scroll.

  An operation panel 51 provided on the front surface of the housing 37 is provided with a start switch button 52, a stop switch button 53, an operation hour meter 54, a discharge pressure display portion 55, and the like.

  Reference numeral 57 denotes an inverter circuit (motor rotation control means) that controls the rotation speed of the motor 39 that drives the compressor 5. The rotation speed of the motor 39 is set according to the use state of the compressed air stored in the air tank 40. Slow down. This inverter circuit 57 temporarily converts a sine wave alternating current into a direct current by a converter (not shown), for example, and reversely converts this to a variable frequency alternating current by turning on and off a transistor (not shown). The rated frequency of 39 can be arbitrarily changed.

Accordingly, the output shaft of the motor 39 is rotationally driven at a rotational speed corresponding to the AC variable frequency output from the inverter circuit 57. Therefore, as will be described later, the inverter circuit 57 controls the motor 39 that drives the compressor 15 only during the adsorption process so as to increase the amount of compressed air generated by the compressor 15, and the pressure of the air tank 40 is equal to or higher than a predetermined value. When the amount of compressed air used is small in a state where the pressure is increased (for example, 6.5 kgf / m ² or more), the rotation speed of the motor 39 is reduced to prevent the compressed air from being exhausted wastefully.

  Pipes 24 and 25 on the take-out side are connected to the upper portions of the adsorption tanks 27A and 27B, and a pressure equalizing pipe 26 for connecting the adsorption tanks 17A and 17B is horizontally placed between the two pipelines 24 and 25. Has been. The pipes 24 and 25 are connected to a pipe 27 that connects the adsorption unit 17 and the storage unit 18. Further, a silencer 32 is provided in the exhaust pipes 22 and 23 that connect between the air supply pipes 20 and 21.

The storage unit 18 includes a nitrogen tank 33 that stores N ₂ gas as a product gas, and an oxygen sensor 34 that measures the oxygen concentration in the nitrogen tank 33. The pipe 27 is connected to the lower part of the nitrogen tank 33, and the high purity N ₂ gas separated in the adsorption tanks 17 A and 17 B is supplied to the nitrogen tank 33 through the pipe 27. An extraction pipe 35 for extracting N ₂ gas is connected to the upper part of the nitrogen tank 33. The take-out conduit 35 extends to a device (not shown) that uses downstream N ₂ gas.

  Further, the oxygen sensor 34 is connected to the nitrogen tank 33 via a pipe line 36.

Normally closed solenoid valves V _{1 to} V ₁₁ are disposed in the pipes 20 to 26, 35, and 36, and the solenoid valves V _{1 to} V ₈ are controlled by signals from the control device 12 as will be described later. The valve is selectively opened according to each step of reflux, adsorption, regeneration, removal, and pressure equalization.

  In the gas separation device 11, the operation of the start switch button 52 activates the motor 39 of the compressor 15 to drive the compressor 38. The compressed air generated by the compressor 38 is accumulated in the air tank 40. The compressed air in the air tank 40 is supplied to the air dryer 13 and dehumidified, and then supplied to the adsorption unit 17.

  FIG. 3 is a process diagram showing the valve operation of each process and the pressure change in each adsorption tank.

  As shown in FIG. 3, in the adsorption unit 17, the compressed air dried by the air dryer 13 is supplied into the first and second adsorption tanks 17A and 17B, and the pressure is increased and the pressure is reduced. And oxygen are separated. In order to stably supply nitrogen as a product gas in the adsorption unit 17, the first adsorption tank 17A is pressurized and the second adsorption tank 17B is depressurized during the adsorption process, and the regeneration process is performed. Conversely, when the first adsorption tank 17A is a regeneration process, the second adsorption tank 17B is an adsorption process.

Accordingly, the control device 12 controls the opening and closing of the valves V _{1 to} V ₁₁ of the adsorption unit 7 so that the adsorption tanks 17A and 17B alternately generate nitrogen gas based on a program inputted in advance.

Here, the operation of the valves V _{1 to} V ₉ of the adsorption unit 17 that opens and closes for each process in the gas separation device 11 configured as described above will be described.

As shown in FIG. 3, each of the valves V _{1 to} V ₉ indicates that “white” is in an open state and “black” is in a closed state. (1) 1st process (adsorption tank A = reflux / adsorption, adsorption tank B = regeneration)
In FIG. 3, valves V ₁ , V ₃ and V ₆ are opened. Therefore, compressed air from the dryer 13 is supplied to the adsorption tank 17A from below, and nitrogen gas from the nitrogen tank 33 is refluxed from above. At the same time, the amount of compressed air supplied from the compressor 15 is increased by the inverter circuit 57 as described above, the pressure in the adsorption tank 17A is increased in a short time, and the adsorbent filled inside adsorbs oxygen molecules.

  The adsorbent made of porous molecular sieve carbon adsorbs oxygen molecules according to the pressure change in the adsorption tank 17A due to the relationship between the pressure and the amount of adsorption, and desorbs oxygen molecules due to the pressure difference when the pressure is reduced.

As can be seen from the diagram of the compressor supply pressure in FIG. 3, even if compressed air is supplied from the air tank 40 of the compressor 15 to the adsorption tank 17 </ b> A during the adsorption process, the speed increase operation of the motor 39 increases the adsorption tank 17 </ b> A. The pressure supplied to the air does not drop rapidly, and the compressed air is stably supplied. Further, since the adsorption performance in the adsorption tank 17A is not significantly improved when the pressure exceeds a predetermined pressure (for example, 5 kg / cm ² ), the pressure in the adsorption tank 17A is actually kept constant at a pressure of about 5 kg / cm ^2. In addition, the operating state of the compressor 15, in other words, the rotational speed of the motor 39 is controlled to increase or decrease.

  In the other adsorption tank 17B, the residual gas is exhausted into the atmosphere and decompressed by opening the valve V6. Therefore, the filler filled in the adsorption tank 17B is regenerated by desorbing the oxygen molecules adsorbed in the previous adsorption step.

And since the adsorption | suction tank 28 provided in the pressure equalization pipe 26 has the valve | bulb V9 of the exhaust pipe 29 opened, the inside is pressure-reduced to atmospheric pressure and adsorbent is reproduced | regenerated. (2) Second step (adsorption tank A = removal, adsorption tank B = regeneration)
In FIG. 3, valves V ₁ , V ₃ and V ₆ are opened as in the first step.

In the adsorption tank 17A, since the compressed air is continuously supplied by opening the valve V1, the pressure is increased to near the supply pressure of the compressor 15 in a short time. Then, the nitrogen gas generated separated by the adsorbent is taken out into a nitrogen tank 33 through a valve V _3.

Incidentally, the other adsorption tank 17B is a regeneration step by opening the valve V _6. Further, as described above, the compressor 15 returns to the steady speed operation at the end of the adsorption process of the adsorption tank 17A. (3) Third step (Adsorption tank A, Adsorption tank B = equal pressure)
In FIG. 3, after the valves V ₁ , V ₃ , V ₆ are closed, the valves V ₄ , V _{8 of the} pressure equalizing pipeline 26 are opened.

  Since the extraction process is completed in one of the adsorption tanks 17A, the pressure is increased to approximately the supply pressure from the compressor 15, whereas in the other adsorption tank 17B, the regeneration process is completed, so the pressure is reduced to approximately atmospheric pressure. . Further, the adsorption tank 28 provided in the pressure equalizing pipe 26 is also decompressed after the regeneration process is completed.

Therefore, N ₂ gas with a high nitrogen concentration remains in the adsorption tank 17A in a pressurized state.

When the valves V ₄ and V ₈ disposed on both sides of the pressure equalizing adsorption tank 28 are opened, the N ₂ gas in the adsorption tank 17A is supplied to the adsorption tank 28 through the valve V ₄ as a pressure equalizing gas. The When the pressure in the adsorption tank 28 is increased, oxygen molecules contained in the pressure equalizing gas are adsorbed by the adsorbent.

Further, the pressure equalizing gas separated and generated by the adsorption tank 28 is sent to the adsorption tank 17B as N ₂ gas having a higher purity than when taken out from the adsorption tank 17A. Accordingly, the adsorption tank 17B is pressurized by the high-purity N ₂ gas supplied through the adsorption tank 28, and is prepared for the next adsorption step.

In this way, in the pressure equalization process, the one adsorption tank 17A that has been pressurized by opening the valves V ₄ and V ₈ is rapidly decompressed, so that the oxygen molecules adsorbed on the adsorbent in the previous adsorption process are desorbed. Will be. Therefore, although the nitrogen concentration of the pressure equalizing gas is reduced, oxygen molecules in the pressure equalizing gas are adsorbed by the adsorbent filled in the adsorption tank 28 provided in the pressure equalizing pipe 26. Purity N ₂ gas generation efficiency is increased. Therefore, the amount of high purity N ₂ gas generated is increased, and the restart time can be further shortened.

In the pressure equalization process, the compressor 15 is periodically rested, so that the compressor 15 is unloaded or stopped. However, if the inter-equalizing pressure time when N ₂ gas consumption is large is short, without the unloading operation or stop state, the normal operation.

  When the first to third steps are completed, the first to third steps are executed so that the adsorption tanks 17A and 17B are switched.

  Here, the control process executed by the inverter circuit 57 will be described.

  FIG. 4 is a flowchart of processing executed by the inverter circuit 57.

  As shown in FIG. 4, when the inverter circuit 57 is in step S <b> 11 (hereinafter, step is omitted), when the first adsorption tank 17 </ b> A or the second adsorption tank 17 </ b> B of the adsorption unit 17 becomes the adsorption process, In S12, the motor 39 of the compressor 15 is accelerated.

The increased speed of the motor 39 increases the amount of compressed air supplied to the compressor 15 and increases the amount of compressed air supplied to the first adsorption tank 17A or the second adsorption tank 17B. Therefore, the pressurization time until reaching a predetermined pressure (for example, 5 kgf / cm ² ) in the adsorption tank 17A or the adsorption tank 17B is shortened, and the adsorption process time can be shortened.

  When the rotation speed of the scroll compressor 38 is constant, the amount of compressed air is also constant, and the amount of compressed air supplied to the adsorption tanks 17A and 17B may be insufficient. However, in this embodiment, since the motor 39 of the compressor 15 is increased in S12, the shortage of pressure at the start of the adsorption process can be resolved as in the case of the reciprocating compressor.

  In the next S13, when the elapsed time since the adsorption process has reached a preset time, the adsorption process is completed, and at the same time, the rotation of the motor 39 is reduced to a steady speed. This is because the compressor 15 is operated beyond its capacity due to the speed increase of the motor 39, and therefore, the rotation speed is reduced in steps other than the adsorption step to reduce the burden on the compressor 15 and extend the life of the compressor 15.

  The set time may be the same as the entire time of the adsorption process, but may be a predetermined time until the pressure in the adsorption tanks 17A and 17B reaches a predetermined pressure.

  In S14, the pressure value of the air tank 40 detected by the pressure detector 47 is read.

  In the next S15, the control target corresponding to the pressure value of the air tank 40 detected in S14 is obtained from the data (see FIG. 5) indicating the relationship between the discharge pressure and the rotation speed of the compressor 15 stored in advance in the memory. The rotational speed (target value) of the motor 39 is read.

  In S16, the rotation speed of the motor 39 is controlled to be the rotation speed (target value) of the motor 39 read in S15. That is, the rotation control of the motor 39 is performed based on the pressure value of the air tank 40 as shown in FIG. For example, as shown in graph I in FIG. 5, in the case of a normal scroll compressor, control is performed so that the rotation speed of the motor 39 is kept at a constant value. In this case, as shown in the graph II, the discharge flow rate from the compressor 38 is also substantially constant regardless of the discharge pressure.

In the present embodiment, as shown in the graph III, when the pressure of the air tank 40 is 2 kgf / cm ² , for example, the pressure is low to perform the adsorption process. The discharge flow rate from the machine 38 is increased. Thereby, as shown in the graph IV, the discharge flow rate from the compressor 38 increases and the shortage of raw material air during the adsorption process can be solved.

Further, as the pressure in the air tank 40 increases, the rotational speed of the motor 39 is gradually reduced to decrease the discharge flow rate from the compressor 38. Further, as shown in the graph III, when the discharge pressure becomes 6 kgf / cm ² or more, the pressure of the air tank 40 is sufficient to perform the adsorption process, so the rotational speed of the motor 39 is rapidly decelerated as shown by the broken line. To do.

  As a result, as shown in graph IV, the amount of air that the compressor 38 exhausts into the atmosphere can be greatly reduced, and the amount of compressed air generated can be reduced with respect to the use state of the compressed air. The operation efficiency of 38 can be increased.

  After the rotation control of the motor 39 is performed in S16 as described above, the process proceeds to S17, and when the suction unit 17 enters the pressure equalizing process, the process returns to S11 to prepare for the next suction process. Therefore, since the speed of the motor 29 increases, the amount of compressed air supplied to the compressor 15 increases and the adsorption process time is shortened. Therefore, one cycle time by a series of adsorption, regeneration, removal, and pressure equalization processes is shortened, and the compressor 5 is made large. Nitrogen production efficiency is improved without conversion.

  Next, a first modification of the present invention will be described.

  FIG. 6 is a configuration diagram showing the configuration of the first modification.

As shown in FIG. 6, a flow meter 61 for measuring the discharge flow rate of N ₂ gas is disposed in the take-out conduit 35 for taking out N ₂ gas (product gas) from the upper part of the nitrogen tank 33. That is, the flow meter 61 measures the amount of N ₂ gas supplied downstream of the gas separation device 11 and outputs the flow rate measurement value to the control device 12.

  FIG. 7 is a flowchart showing the process of the first modification executed by the inverter circuit 57.

  In FIG. 7, the processing of S21 to S23 is the same as S11 to S13 of FIG.

In S24, the discharge flow rate of N ₂ gas measured by the flow meter 61 is read.

In the next S25, it corresponds to the N ₂ gas discharge flow rate detected in S24 from the data (see FIG. 5) showing the relationship between the N ₂ gas discharge flow rate and the rotation speed of the compressor 15 stored in the memory in advance. The number of rotations (target value) of the motor 39 as a control target is read.

In S26, the rotation speed of the motor 39 is controlled to be the rotation speed (target value) of the motor 39 corresponding to the N ₂ gas discharge flow rate read in S25. That is, the rotation control of the motor 39 is performed based on the discharge flow rate of the N ₂ gas as shown in FIG. 5. When the discharge flow rate of the N ₂ gas is large as in the case of S16 described above, the rotation speed of the motor 39 is increased. And the discharge flow rate from the compressor 38 is increased. Thereby, the discharge flow rate from the compressor 38 increases, and the shortage of raw material air during the adsorption process can be solved.

Further, as the pressure in the air tank 40 increases, the rotational speed of the motor 39 is gradually reduced to decrease the discharge flow rate from the compressor 38. Furthermore, when the discharge flow rate of N ₂ gas becomes a predetermined value or less, the pressure in the nitrogen tank 33 is sufficient, so that the rotational speed of the motor 39 is rapidly reduced.

  As a result, as shown in graph IV, the amount of air that the compressor 38 exhausts into the atmosphere can be greatly reduced, and the amount of compressed air generated can be reduced with respect to the use state of the compressed air. The operation efficiency of 38 can be increased.

  Next, a second modification of the present invention will be described.

  FIG. 8 is a configuration diagram showing the configuration of the second modification.

  As shown in FIG. 8, pressure detectors 62 and 63 for detecting the pressure in the adsorption tanks 17A and 17B are attached to the adsorption tanks 17A and 17B. That is, the pressure detectors 62 and 63 detect pressure changes in the adsorption process, the extraction process, and the regeneration process, and output the detected pressure values to the control device 12.

  FIG. 9 is a flowchart showing the process of the second modification executed by the inverter circuit 57.

  In FIG. 9, the processing of S31 to S33 is the same as S11 to S13 of FIG.

In S34, the pressure values P _A and P _B of the adsorption tanks 17A and 17B detected by the pressure detectors 62 and 63 are read.

In the next S35, the memory in advance stored adsorbing vessel 17A, the pressure _P A of 17B, _{P B} and the suction chamber 17A from the data (see FIG. 5) detected by the S34 showing the relationship between the rotational speed of the compressor 15 , 17B, the rotation speed (target value) of the motor 39 corresponding to the pressure value is read.

In S36, the rotational speed of the motor 39 is controlled to be the rotational speed (target value) of the motor 39 corresponding to the pressures P _A and P _B of the adsorption tanks 17A and 17B read in S35. That is, the rotation control of the motor 39 is performed based on the pressures P _A and P _B of the adsorption tanks 17A and 17B as shown in FIG. 5, and the pressure value P of the adsorption tanks 17A and 17B is the same as in S16 described above. _{When A 1} and P _B decrease to a predetermined value or more, the rotational speed of the motor 39 is increased to increase the discharge flow rate from the compressor 38. Thereby, the discharge flow rate from the compressor 38 increases, and the shortage of raw material air during the adsorption process can be solved.

Further, as the pressures P _A and P _{B of} the adsorption tanks 17A and 17B are increased, the number of revolutions of the motor 39 is gradually reduced to decrease the discharge flow rate from the compressor 38. Further, when the pressures P _A and P _{B of} the adsorption tanks 17A and 17B are 6 kgf / cm ² or more, the pressure of the air tank 40 is sufficient to perform the adsorption process, and thus the rotational speed of the motor 39 is rapidly reduced. .

  As a result, the amount of air that the compressor 38 exhausts compressed air into the atmosphere can be greatly reduced, and the amount of compressed air generated is reduced with respect to the use state of the compressed air, and the operating efficiency of the compressor 38 is increased. be able to.

  In the above embodiment, the inverter circuit 47 is taken as an example. However, the present invention is not limited to this. For example, the rotation speed may be controlled by varying the supply voltage to the motor 29.

  Moreover, in the said Example, although a pair of adsorption tank 7A, 7B is provided, of course, it can apply also to the apparatus which has two or more adsorption tanks.

  In the above embodiment, each adsorption tank is configured to adsorb oxygen molecules, but it is needless to say that each adsorption tank can be applied to a structure (for example, an oxygen generator) that adsorbs other gas molecules.

DESCRIPTION OF SYMBOLS 11 Gas separation apparatus 12 Control apparatus 13 Refrigeration dryer 15 Compressor 16 Air supply unit 17 Adsorption unit 17A, 17B Adsorption tank 18 Storage unit 38 Compressor main body 39 Motor 40 Air tank 46 Rotation detector 47 Pressure detector 57 Inverter circuit 61 Flow rate Total 62,63 Pressure detector

Claims (4)

A gas configured to supply compressed air from a compressor to an adsorption tank filled with an adsorbent to increase the pressure in the adsorption tank, and to take out product gas generated by the adsorbent in the adsorption tank from the adsorption tank In the separation device,
Detecting means for detecting a use state of compressed air from the compressor;
Rotation detection means for detecting the rotation speed of a motor for driving the compressor;
Rotation control means for decelerating the rotation speed of the motor at a predetermined rate when the amount of compressed air detected by the detection means is less than or equal to a predetermined value;
A gas separation device comprising:   2. The gas separation device according to claim 1, wherein the detection means comprises a pressure detector for detecting the pressure of the air tank of the compressor.   2. The gas separation device according to claim 1, wherein the detection means comprises a flow meter for detecting a discharge flow rate of the product gas.   The gas separation device according to claim 1, wherein the detection unit includes a pressure detector that detects a pressure in the adsorption tank.

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