JP2008295594A - Oxygen concentrator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent an incident in which oxygen having a desired flow rate or concentration is not acquired because of the performance degradation of a compressor even when a motor rotates at the prescribed number of rotations in an oxygen concentrator loaded with the compressor equipped with the motor of the variable number of rotations. <P>SOLUTION: The oxygen concentrator controls to increase the number of rotations of the DC brushless motor 7a for driving the compressor 7 to the prescribed number of rotations to keep a detected greatest pressure at a set reference pressure or more when the detected greatest pressure of compressed air sent into nitrogen absorption containers 31, 32 is lower than the set reference pressure. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an oxygen concentrator suitable for use in home therapy by patients with respiratory diseases and the like.

  This type of oxygen concentrator (also referred to as an oxygen concentrator, hereinafter simply referred to as an apparatus) is a so-called pressure fluctuation adsorption method (PSA) using a nitrogen adsorbent that preferentially adsorbs nitrogen over oxygen. Oxygen concentrators based on this method are widely used (for example, Patent Document 1). In this method of oxygen concentrator, air (atmosphere) is compressed by a compressor, which is an air compression means, and filled with a zeolite-based nitrogen adsorbent (particles), for example, two nitrogen adsorption containers (hereinafter referred to as adsorption). An adsorption process (pressurization process) in which compressed air is alternately supplied into a container or simply a container), and the inside of the container is pressurized to adsorb nitrogen in the air to the nitrogen adsorbent to extract oxygen. And a regeneration process (decompression process) in which the adsorbed nitrogen is exhausted by opening the container to the atmosphere and depressurizing, and the nitrogen adsorbed by the nitrogen adsorbent is desorbed to regenerate the nitrogen adsorbent. It is configured so that it is repeatedly performed every second, and a high-concentration oxygen-containing gas (hereinafter also simply referred to as oxygen) is continuously generated and taken out and supplied to the patient.

  By the way, in such an oxygen concentrator, an appropriate amount of oxygen flow to be supplied to a patient varies in a range of, for example, 0.25 L / min to 5 L / min according to the patient's symptoms. On the other hand, the oxygen flow rate that can be taken out is determined based on the flow rate of compressed air fed into the nitrogen adsorption container by the compressor. In the compressor (reciprocating type compressor), the amount of compressed air is determined by the inner diameter of the cylinder, the stroke of the piston, and the rotational speed of the motor that reciprocates the cylinder. For this reason, in order to efficiently supply an appropriate amount of oxygen according to the patient, a motor having a variable rotational speed is used in the compressor used in this type of apparatus, such as a DC brassless motor. Therefore, the rotation is performed at a rotation speed at which a desired amount of oxygen can be obtained.

  In an oxygen concentrator equipped with such a compressor, it can be obtained by setting a desired oxygen flow rate (taken oxygen flow rate) with a flow rate setting device installed on the oxygen take-out port side. As described above, there is one in which the rotation of a motor is controlled at a predetermined number of rotations (Patent Document 2). That is, according to this oxygen concentrator, the motor that drives the compressor discharges a predetermined amount of compressed air from which the oxygen flow rate can be extracted by setting the oxygen flow rate required for the user (patient) with the flow rate setting device. It is controlled to rotate at a rotation speed (hereinafter also referred to as a basic rotation speed).

However, in this oxygen concentrator, even if the motor rotates at a predetermined basic rotational speed, the amount of compressed air that should be discharged at that rotational speed is not discharged, and as a result, the desired oxygen is set. In some cases, the flow rate and thus the desired oxygen concentration could not be obtained. There are various reasons or factors. For example, the adsorbent has an oxygen recovery rate that changes depending on the ambient adsorption temperature at which the oxygen concentrator is installed. May not provide the desired oxygen concentration. And as this countermeasure, there exists invention which controls the rotation speed of the motor of a compressor based on the environmental temperature of the circumference | surroundings (patent document 3).
JP 2003-246607 A JP 2007-089684 A JP 2006-141896 A

  On the other hand, there is no problem due to the ambient environmental temperature, and even if the motor rotates at a predetermined basic rotational speed corresponding to the flow rate set by the flow rate setting device, the predetermined oxygen flow rate and oxygen concentration may not be obtained. . This is due to deterioration (decrease) in the durability or performance of the compressor itself due to aging, etc. Even if the motor is rotating at a predetermined basic rotational speed, the compressed air at the target flow rate will be reduced. Occurs when ejection is not possible. Specifically, it is as follows. When the compressor is used for a long period of time, the sealing material (also referred to as cup packing) provided on the outer peripheral surface of the piston will deteriorate over time and wear. For this reason, the effect | action which the sealing material presses a cylinder internal peripheral surface (sliding surface), ie, a sealing performance, falls, and the compression efficiency of air falls. This is a shortage of the discharge amount, leading to a decrease in the amount of air sent into the nitrogen adsorption container, resulting in a shortage of oxygen flow that can be taken out.

  That is, if there is such a deterioration in the performance of the compressor, even if the motor itself rotates at a predetermined rotational speed, the amount of compressed air sent into the nitrogen adsorption container is reduced, so that the internal pressure (maximum Pressure) decreases. As a result, the oxygen flow rate that can be generated and taken out is reduced, leading to a decrease in the oxygen concentration. And such a problem means that in the user, when the predetermined oxygen flow rate is set by the flow rate setting device, oxygen deficiency is actually generated. As a countermeasure against such a problem, it is conceivable that the motor speed corresponding to the set oxygen flow rate is set to a higher value (higher) from the beginning in anticipation of the compressor performance degradation to some extent. Prior to deterioration, wasteful power consumption is incurred, and it is against the request for low noise.

  The present invention has been made in view of these problems, and in an oxygen concentrator equipped with a compressor having a motor with a variable rotation speed, the motor rotates at a predetermined rotation speed due to deterioration in performance of the compressor. Even if it does, it exists in preventing generation | occurrence | production of the situation where oxygen of the desired flow volume and density | concentration cannot be obtained.

The present invention according to claim 1 is an oxygen concentrator that generates high-concentration oxygen gas by sending compressed air by a compressor into a nitrogen adsorption vessel having a nitrogen adsorbent that preferentially adsorbs nitrogen therein. There,
The motor that drives the compressor has a variable number of rotations, and is configured so that the number of rotations of the motor is set based on the flow rate of high-concentration oxygen gas taken out after generation. When the detected maximum pressure of the compressed air to be fed is lower than a set reference pressure, control is performed to increase the rotational speed of the motor.

  According to a second aspect of the present invention, in the first aspect, when the detected maximum pressure of the compressed air sent into the nitrogen adsorption container is lower than a set reference pressure, the rotation speed of the motor is set to a predetermined rotation. The oxygen concentrator is characterized in that it is continuously driven for a predetermined time after being increased to a number, and is controlled to return to the rotation speed before the increase after the lapse of the predetermined time.

  According to a third aspect of the present invention, when the detected maximum pressure of the compressed air sent into the nitrogen adsorption container is lower than a set reference pressure, the number of rotations of the motor is determined based on the detected maximum pressure. The oxygen concentrator according to claim 1 or 2, wherein the oxygen concentrator is controlled to increase until the pressure is maintained above the pressure.

  In the present invention, the “maximum detected pressure” refers to the maximum gas pressure (pressure) detected when the inside of the nitrogen adsorption container is in the pressurizing step. In this type of oxygen concentrator, the pressure in the nitrogen adsorption vessel is not constant, for example, during a pressurizing process of 10 seconds, and usually has a fluctuating pressure that exhibits a peak (maximum) at or near the middle of the pressurizing process. Become. Therefore, of the detected pressure (gas pressure), the peak value at the fluctuating pressure is the detected maximum pressure.

  Further, in the present invention, the “reference pressure” is a pressure (gas pressure) that serves as a reference for determining whether or not the rotation speed of the motor should be increased as compared with the detected maximum pressure. The target maximum pressure (gas pressure) obtained by rotating at a predetermined basic rotational speed, or the target maximum pressure in consideration of variations in pressure due to individual differences in the oxygen concentrator, etc. Set lower than pressure.

  In the present invention, the maximum pressure (peak value) of the compressed air sent into the nitrogen adsorption container in the pressurization step is detected as the maximum detection pressure, and this is compared with a preset reference pressure, and the maximum detection pressure is the reference. When the pressure is lower than the pressure, control is performed to increase the rotational speed of the motor. When the detected maximum pressure of the compressed air sent into the nitrogen adsorption container is lower than the reference pressure, in the pressurizing process of the nitrogen adsorption container, other spaces (in the product tank and Since the air pressure or high-concentration oxygen gas pressure existing in the pipes connected to the same is also lower than the reference pressure, the detection location of the maximum detected pressure is not limited to the nitrogen adsorption vessel, but the internal space You may detect in the other space which is in a communication state. The detection may be performed by a pressure sensor (or a pressure gauge).

  As described above, if a compressor performance deterioration symptom (for example, wear of pinton seal material) occurs, the compression efficiency of the air decreases, so even if the motor is rotating at a predetermined basic rotational speed, Compressed air with a target flow rate corresponding to the basic rotational speed cannot be discharged. This means a decrease in the amount of compressed air sent into the nitrogen adsorption container, so that the gas pressure in the container decreases. Therefore, the maximum pressure (peak value) in the container also decreases, leading to a decrease in the flow rate and concentration of oxygen that can be taken out.

  On the other hand, in the present invention of claim 1, such a gas pressure is monitored to detect the maximum pressure, and when the detected maximum pressure is less than the reference pressure value, the rotation of the compressor motor is detected. The control is to increase the number. That is, in the present invention, the shortage of the flow rate of the compressed air sent into the nitrogen adsorption container is determined from the detected maximum pressure, and when the pressure is lower than the reference pressure, the motor speed is increased. Yes. Therefore, according to the present invention, it is possible to prevent a situation in which the compressor does not discharge a predetermined amount of compressed air due to performance deterioration, and the amount and concentration of oxygen that can be taken out due to the discharge are reduced.

  As described above, according to the present invention, even when the performance of the compressor is deteriorated, oxygen having a desired flow rate and concentration can be stably supplied to the patient. As a result, the life of the oxygen concentrator is prolonged. can do. When the detected maximum pressure is lower than the set reference pressure, the motor speed is controlled to increase to a predetermined speed so that the detected maximum pressure is maintained above the set reference pressure. Is preferred.

  In the present invention, as described in claim 2, after the elapse of a predetermined time, the rotational speed before increase (basic rotational speed) may be restored. The reason is as follows. Of the performance deterioration of the compressor, those caused by the above-mentioned poor seals are often empirically found that the target flow rate of compressed air cannot be discharged only in a short period of time immediately after the start of driving of the compressor. That is, after a certain short period of time (depending on the ambient temperature, etc., it is generally unclear, but generally 5 to 15 minutes), the target flow rate is compressed even if the basic rotational speed before the increase is restored. In many cases, the state in which air is discharged can be maintained, and the detected maximum pressure can be maintained at a reference pressure or higher. Therefore, if the rotation speed is returned to the pre-increase speed after a predetermined time has elapsed, power consumption can be reduced as compared with the case where the rotation speed is kept high. In this way, even when returning to the rotational speed before the increase after a predetermined time has passed, if the detected maximum pressure is lower than the set reference pressure, the detected maximum pressure is set to the rotational speed of the motor. It is preferable to control to increase to a predetermined number of revolutions so that the pressure is maintained at or above the reference pressure.

  In addition, the reason why the pressure drop is naturally eliminated is considered as follows. This is because when the compressor is driven for a certain period of time, the inside of the cylinder is sufficiently warmed up, and the heat expands the seal material, or when the seal material is cup packing, the peripheral wall portion is sufficiently outward. It is considered that the airtightness of the sliding surface between the piston and the cylinder is ensured to be high. This is because when the temperature at the start of compressor operation is low, such as during low temperatures such as in winter, or when the motor speed is relatively low, such as when the oxygen flow rate is small (the piston reciprocating cycle). In the case where the number is relatively small), it is estimated from the fact that the time until the resolution is long is short, whereas the time is short when the environmental temperature is high or the rotational speed of the motor is relatively high.

  Next, an example of the best mode for carrying out the present invention (Example 1) will be described with reference to FIGS. FIG. 1 shows concentration of oxygen by adsorbing and removing nitrogen from the air using a nitrogen adsorbent (hereinafter also referred to as an adsorbent), and supplying a high concentration oxygen gas containing this high concentration oxygen to the patient. 1 shows an example of a pressure fluctuation adsorption type medical oxygen concentrator that performs as a piping system diagram (circuit diagram). First, based on this FIG. 1, the whole structure of the oxygen concentration apparatus 1 of a present Example is demonstrated.

  In the oxygen concentrator 1 of this embodiment, as shown in the circuit diagram of FIG. 1, the air taken in from the air intake port 2 is supplied to the compressor 7 through the dustproof filter 4a, the intake filter 4b, and the like. In this example, the air compressed by the compressor 7 is supplied to compressed air supply pipes 10, 11, 12 in nitrogen adsorption containers (also referred to as a first adsorption container or a second adsorption container) 31, 32 arranged in parallel. The switching valves (open / close valves) 41 and 42 made up of electromagnetic valves provided in the middle of the branch pipes 11 and 12 are alternately controlled to open and close via the check valves 21 and 22, respectively. The first adsorption container 31 or the second adsorption container 32 is alternately sent. The first and second adsorption vessels 31 and 32 are filled with, for example, zeolite (powder or granules) as a nitrogen adsorbent that selectively adsorbs nitrogen over oxygen.

  Then, when the compressed air passes through the first adsorption vessel 31 (or 32), nitrogen in the air is adsorbed by the adsorbent to become a high oxygen concentration gas, and the high oxygen concentration gas transport pipe 21 (or 22). ) And is fed into the storage product tank 71 via the check valve 61 (or 62). At this time, the nitrogen adsorbed by the adsorbent in the other nitrogen adsorption vessel opens and closes the switching valves 43 and 44 including electromagnetic valves from the exhaust pipes 15 and 16 branched in the middle of the compressed air supply pipes 11 and 12. By controlling, it is discharged to the outside through the exhaust muffler 60, and the nitrogen adsorbent is regenerated. In each of the high oxygen concentration gas transfer pipes 21 and 22, the portions connecting the nitrogen adsorption containers 31 and 32 and the check valves 61 and 62 are connected by a connection pipe 27, and when nitrogen is discharged. The solenoid valve (purge open / close valve; hereinafter also referred to as a purge valve) 63 provided in the middle of the connecting pipe 27 is opened for a certain period of time, so that the gas in the nitrogen adsorption vessel on the pressurizing process side By exhausting a part of it back to that of the exhaust side, exhaust of nitrogen is promoted. Note that orifices (fixed restrictors) 28 and 29 are provided on both sides of the purge valve 63.

  Thus, by controlling opening and closing of the valves such as the switching valves 41 to 44 via the control device 201 described later, the compressed air is alternately sent to the two nitrogen adsorption containers 31 and 32, and it is sent. When one is in the pressurizing step, the other is in the depressurizing step, and the high oxygen concentration gas is alternately generated and sent to the product tank 71. The high oxygen concentration gas fed into the product tank 71 is regulated (pressure regulated) by a regulator (pressure regulating valve) 73, filtered by a filter (not shown), and the flow rate is adjusted by a flow rate setting device 75. It is sent to the oxygen outlet 82 via the humidifier 79 or the like and supplied to the patient via a cannula (not shown).

  In the above example, as shown in FIG. 1, a pressure sensor 25 for detecting the gas pressure in the pipe (same as the gas pressure in the adsorption container) is provided in the middle of the compressed air supply pipe 10. Yes. An oxygen sensor 77 that detects the oxygen concentration is disposed in the middle of the piping between the flow rate setting device 75 and the humidifier 79. These sensors 25 and 77 are connected to the control device 201 described below, and are used by the operation of an alarm device (lamp, buzzer) when it is determined to be abnormal based on signals output from the sensors. The person is informed of the abnormality. The compressor 7 used in the oxygen concentrator 1 of the present example is a DC brushless motor whose motor 7a that drives the compressor 7 has a variable number of rotations, and the number of rotations by an inverter circuit based on the timing of the attached hall sensor. Is set to be controlled.

  Now, a control device (electronic control device) 201 mounted on the oxygen concentrator 1 of this embodiment will be described with reference to FIG. The control device 201 includes a microcomputer 205 and performs various controls including opening and closing of the above-described switching valves 41 to 44 in the oxygen concentrator 1. A power switch 24, an oxygen sensor 77, a flow rate setting device 75, a pressure sensor 25, and the like are connected to the input unit 210 of the control device 201. On the other hand, the output unit 220 of the microcomputer 205 is connected with a motor 7a for driving the compressor 7, first to fourth switching valves 41 to 44, a purge valve 63, a flow rate indicator 64, an operation lamp 65, an alarm device 66, and the like. Has been.

  In this example, the motor (DC brushless motor) 7a that drives the compressor sets the flow rate of oxygen by the flow rate setting device 75, so that compressed air having a flow rate necessary for taking out the set oxygen flow rate is supplied. It is controlled to rotate at a preset basic rotational speed so as to discharge. On the other hand, when the flow rate of the compressed air discharged by the motor 7a rotating at the set basic rotational speed decreases to some extent, the maximum gas pressure in the adsorption containers 31 and 32 does not reach the target maximum pressure. In this example, the reference pressure is set 17% lower than the target maximum pressure. In this example, when the detected maximum pressure detected by the pressure sensor 25 falls below the reference pressure after the start of operation, the control device 201 determines the rotational speed of the motor 7a from the basic rotational speed according to the result. It is programmed to control to increase the rotational speed.

  Accordingly, when the operation of the oxygen concentrator 1 is started by turning on the power switch 24 in such an electronic control device 201, the motor 7a is preset based on a signal indicating the set flow rate set by the flow rate setting device 75. The compressor 7 is driven by rotating at the basic rotational speed. Then, the discharged compressed air is controlled to open and close according to a predetermined time chart, and the valves 41 to 44 and 63 such as switching valves are alternately sent to the nitrogen adsorption vessels 31 and 32, so that the pressurization process and the exhaust are performed. The steps are performed alternately. The oxygen produced by the adsorption of nitrogen in the nitrogen adsorption containers 31 and 32 is sent into the product tank 71, adjusted to the set pressure and flow rate, and supplied from the oxygen outlet 82 to the patient.

  Importantly, in this embodiment, after the operation of the oxygen concentrator 1 is started, the compressor 7 is configured so that the gas pressure of the compressed air becomes an appropriate pressure based on the detected maximum pressure of the compressed air detected by the pressure sensor 25. That is, control is performed to increase the rotational speed of the motor 7a. That is, as described above, the oxygen flow rate is set to a predetermined amount (for example, 1 L / min) by the flow rate setting device 75 according to the patient. Then, first, the compressor 7 rotates the rotational speed of the motor 7a at a basic rotational speed (for example, 600 rpm) so that compressed air from which the set oxygen flow rate (for example, 1 L / min) can be taken out is discharged. Controlled to drive. However, the reference pressure obtained by this rotation is set in advance (for example, 50 kPa), and the detected maximum pressure in the nitrogen adsorption vessel in the pressurizing step when the operation of the oxygen concentrator 1 is started, and this The motor 7a is programmed to be controlled so as to increase its rotational speed to a predetermined rotational speed in accordance with a difference between the reference pressure (50 kPa) and the difference.

  In this example (Example 1), when the detected maximum pressure is less than the reference pressure, for example, when the detected maximum pressure is 30 kPa, the rotational speed of the motor 7a is changed from the basic rotational speed to a predetermined rotational speed (for example, 100%). Up to 1200 rpm), and the compressor 7 is controlled to be driven.

  Here, the control process of the rotation speed of the motor 7a of the compressor 7 will be described based on the flowchart of FIG. When the power switch 24 is turned on, the oxygen concentrator 1 is activated, and the compressor 7 rotates the motor 7a at the set predetermined basic rotational speed by the input of the flow rate setting signal of the flow rate setting device 75. Thereby, the compressed air discharged from the compressor 7 is alternately sent to the containers 31 and 32. At this time, the gas pressure in the container in the pressurizing process is detected by the pressure sensor 25 (step 100). Then, the detected maximum pressure in the container is compared with the reference pressure, and it is determined whether the current pressure is equal to or higher than the reference pressure (step 110).

  As a result, if it is determined that the detected maximum pressure is equal to or higher than the reference pressure, the rotational speed of the motor 7a of the compressor 7 is maintained at the basic rotational speed (for example, 600 rpm) (step 120). That is, the control for rotating the motor 7a at the basic rotational speed is continued, and this routine ends.

  Conversely, if it is determined that the detected maximum pressure is less than the reference pressure, control is performed to increase the rotational speed of the motor 7a from the basic rotational speed to a predetermined rotational speed (step 130). Then, after a predetermined time, the gas pressure (maximum detected pressure) in the container in the pressurizing process is detected by the pressure sensor 25 (step 140), and the detected maximum pressure in the container is compared with the reference pressure. Perform again (step 150). As a result, if it is determined that the current detected maximum pressure is less than the reference pressure again, feedback control for further increasing (increasing) the number of revolutions of the motor 7a is performed, while if it is determined that the detected maximum pressure is greater than the reference pressure. Then, the rotational speed of the motor 7a of the compressor 7 is maintained at the rotational speed (step 160), and this process is terminated.

  As described above, if the inside of the container does not reach the reference pressure even when the motor 7a is rotated at the basic rotation speed, control is performed to increase the rotation speed of the motor 7a to increase the discharge amount of the compressed air. . As a result, the desired set flow rate of oxygen can be obtained, so even if the performance of the compressor 7 deteriorates, the flow rate and concentration of oxygen set by the flow rate setting device 75 can be obtained, eliminating the problem of insufficient oxygen. That is why.

  As another example (example 2), when the detected maximum pressure is less than the reference pressure, for example, when the detected maximum pressure is 30 kPa, the rotational speed of the motor 7a is changed from the basic rotational speed to a predetermined rotational speed (for example, 100% up to 1200 rpm). Then, when a reference pressure or higher is obtained, control is performed to return to the original basic rotational speed (600 rpm) after being held for a certain time (10 minutes). Then, the maximum pressure in the nitrogen adsorption container may be detected again, the detected maximum pressure may be compared with the reference pressure (50 kPa), and feedback control may be performed to repeat the above control. As described above, even when the discharge amount of the compressed air is reduced due to the deterioration of the performance of the compressor 7, if the operation is continued for a predetermined time and the compressor 7 is warmed up, the discharge amount of the compressed air is reduced. In many cases, the decrease is naturally resolved, and thereafter, a stable amount of oxygen is often supplied. Therefore, in such a case, it is possible to reduce power consumption by controlling to reduce the rotational speed, and to contribute to noise reduction by temporarily increasing the rotational speed. Can do.

  FIG. 4 shows a flowchart of this (Example 2). However, the difference from Example 1 is after Step 150, as shown in FIG. In this example, when the maximum pressure in the nitrogen adsorption container is detected and determined to be less than the reference pressure, the motor 7a is raised from the basic rotation speed to a predetermined rotation speed (for example, 1200 rpm) to drive the compressor 7 ( Step 130). Then, after a predetermined time, the gas pressure (maximum detected pressure) in the container in the pressurizing process is detected by the pressure sensor 25 (step 140), and the detected maximum pressure in the container is compared with the reference pressure. Perform again (step 150). As a result, if it is determined that the current detected maximum pressure is less than the reference pressure again, feedback control is performed to further increase the rotational speed of the motor 7a above the basic rotational speed, while if it is determined that the detected pressure is greater than the reference pressure. In this state, the motor is continuously operated for a certain time (for example, 10 minutes), and after that time has elapsed, control is performed to reduce the rotational speed of the motor 7a to the basic rotational speed (600 rpm) corresponding to the set flow rate (step 160). Then, as shown in the flowchart of FIG. 4, this control is repeated.

  The present invention is not limited to the above-described embodiments, and can be implemented in various modes or modified without departing from the scope of the present invention. In the above, when the maximum detected pressure is less than the reference pressure, the initial increase in the number of rotations of the motor is set to be simply doubled. However, this increase may be set so that the reference pressure can be obtained. . In other words, when increasing the rotational speed from the basic rotational speed to the predetermined rotational speed, the range of increase is set based on the check of the rotational speed of the motor that obtains the reference pressure according to the maximum detected pressure in advance. Just keep it. Of course, if the compressor continues to operate for a predetermined period of time and becomes warmed up, the decrease in the amount of compressed air is often eliminated naturally. When the rotational speed is increased from a predetermined rotational speed to a predetermined rotational speed, the amount of increase may be set within a range in which a pressure close to or below the reference pressure can be obtained.

  In the above example, the pressure sensor 25 is attached (installed) in the middle of the pipes 10 to 12 connecting between the discharge port of the compressor 7 and the nitrogen adsorption containers 31 and 32. Although the pipe 10 before the branch (upstream side) that conveys compressed air toward the pipe 32 is used as the installation position, the drop in the discharge flow rate due to the deterioration of the performance of the compressor 7 is the drop in the pressure (maximum detected pressure). As long as it can be confirmed, it may be provided at any position. Therefore, you may provide in adsorption container 31, 32 itself or its vicinity, or product tank 71 or its vicinity. However, as in the above example, when the pressure switch 25 is provided in the pipe 10 on the upstream side (compressor side) from the position of the switching valves 41 and 42 for pressurization, one pressure sensor 25 is sufficient and it is close to the discharge port of the compressor 7. Since it becomes a position, the responsiveness in pressure detection is also good.

The piping system figure for demonstrating the basic composition of the Example which actualized the oxygen concentration apparatus of this invention. Explanatory drawing which shows the structure of the control apparatus of the oxygen concentrator of an Example. Example 1 of a flowchart which shows processing performed with a control device of an example. Example 2 of the flowchart which shows the process performed with the control apparatus of an Example.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Oxygen concentrator 7 Compressor 7a Motor 25 which drives a compressor Gas sensor 31, 32 Nitrogen adsorption container

Claims (3)

An oxygen concentrator of a system that generates high-concentration oxygen gas by sending compressed air by a compressor into a nitrogen adsorption container having a nitrogen adsorbent that preferentially adsorbs nitrogen,
The motor that drives the compressor has a variable number of rotations, and is configured so that the number of rotations of the motor is set based on the flow rate of high-concentration oxygen gas taken out after generation. An oxygen concentrator that controls to increase the number of revolutions of the motor when the detected maximum pressure of the compressed air to be fed is lower than a set reference pressure.   In Claim 1, when the maximum detected pressure of the compressed air sent into the nitrogen adsorption container is lower than a set reference pressure, the rotational speed of the motor is increased to a predetermined rotational speed and continued for a predetermined time. An oxygen concentrator that is driven and controlled to return to the rotational speed before the increase after a predetermined time has elapsed.   When the detected maximum pressure of the compressed air sent into the nitrogen adsorption container is lower than a set reference pressure, the number of rotations of the motor is increased until the detected maximum pressure is maintained above the set reference pressure. The oxygen concentrator according to claim 1 or 2, wherein control is performed.

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