Compressor and management system

Abstract

Provided are a compressor and a management system that are capable of extending the operating life of a compressor while easing the burden on a user.　A compressor 1 comprises a compressor body 3 that compresses air, and a control device 17 that controls the operation of the compressor body 3. If operation of the compressor body 3 is resumed when the stop time of the compressor body 3 is greater than or equal to a preset time A, the control device 17 executes a diagnostic operation mode which determines the presence or absence of abnormalities while reducing the load on the compressor body 3 relative to a regular operation mode.

Description

Compressor and management system

[0001] The present invention relates to a compressor and a management system.

[0002] Patent Literature 1 discloses a management system including a compressor having a compressor main body for compressing gas and a control means for controlling the operation of the compressor main body, a management center that communicates with the control means via a network and receives operation information of the compressor main body from the control means, and a user terminal that communicates with the management center via the network. If the compressor main body has been stopped for a predetermined time or longer, the information processing means of the management center transmits information to the user terminal prompting maintenance of the compressor main body.

[0003] JP 2014-010685 A

[0004] If the compressor main body is stopped for a long time, for example, the oil stored in the compressor main body or the components connected to it may deteriorate. Furthermore, for example, moisture in the air inside the compressor main body or the components connected to it may condense, generating drainage, which may then cause rust. Therefore, if the compressor main body is stopped for a very long time, maintenance of the compressor main body or its components should be performed. However, depending on the length of time the compressor main body is stopped, it may be difficult to determine whether maintenance should be performed. Performing maintenance even when it is not necessary will burden the user. On the other hand, not performing maintenance even when it is necessary will shorten the compressor's lifespan.

[0005] The present invention has been made in view of the above circumstances, and one of its objects is to extend the life of a compressor while reducing the burden on the user.

[0006] In order to solve the above-mentioned problems, the present invention applies the configurations described in the claims. The present invention includes a plurality of means for solving the above-mentioned problems, and as one example, in a compressor including a compressor main body that compresses gas and a control device that controls the operation of the compressor main body, when the compressor main body is restarted after being stopped for a predetermined first time period or longer, the control device executes a diagnostic operation mode in which the load on the compressor main body is reduced more than in a normal operation mode and the presence or absence of an abnormality is determined.

[0007] According to the present invention, it is possible to extend the life of the compressor while reducing the burden on the user.

[0008] Problems, configurations, and effects other than those described above will become clear from the following description.

[0009] Fig. 1 is a schematic diagram showing the configuration of a compressor in a first embodiment of the present invention. Fig. 2 is a flowchart showing the processing content of a control device in the first embodiment of the present invention. Fig. 3 is a diagram showing the configuration of a management system in a second embodiment of the present invention. Fig. 4 is a flowchart showing the processing content of a management server in a second embodiment of the present invention. Fig. 5 is a schematic diagram showing the configuration of a compressor in a first modified example of the present invention. Fig. 6 is a schematic diagram showing the configuration of a compressor in a second modified example of the present invention.

[0010] A first embodiment of the present invention will be described with reference to the drawings.

[0011] FIG. 1 is a schematic diagram showing the configuration of a compressor according to this embodiment.

[0012] The compressor 1 of this embodiment includes an electric motor 2, a compressor main body 3 that is driven by the electric motor 2 and compresses air (gas) while injecting oil into a working chamber, a filter 4 that is disposed on the suction side of the compressor main body 3 and removes foreign matter from the air, a separator 5 that separates oil from the compressed air (compressed gas) discharged from the compressor main body 3 and stores the separated oil, an oil pipe 6 that supplies the oil stored in the separator 5 to the working chamber of the compressor main body 3, and a compressed air pipe 7 (compressed gas pipe) that supplies the compressed air separated by the separator 5 to the outside. The compressor 1 is configured as a unit that houses the above-mentioned devices and the like in a housing.

[0013] The compressor body 3 has, for example, a pair of intermeshing male and female screw rotors and a casing that houses the screw rotors, with multiple working chambers formed in the tooth grooves of the screw rotors. Each working chamber moves axially as the rotor rotates, and sequentially performs an intake process to draw in air, a compression process to compress the air, and a discharge process to discharge the compressed air. The compressor body 3 is designed to inject oil into the working chambers for the purposes of cooling the heat of compression, sealing the working chambers, and lubricating the rotors.

[0014] The separator 5 has, for example, a swirl flow path that swirls the compressed air, separates oil from the compressed air by centrifugal separation, and stores the separated oil. An oil pipe 6 supplies oil from the separator 5 to the working chamber of the compressor body 3 by using the pressure difference between the separator 5 and the working chamber of the compressor body 3. The oil pipe 6 is provided with an oil cooler 8 that cools the oil, a temperature control valve 9 that adjusts the flow rate ratio between the oil cooler 8 and a flow path that bypasses it, and an oil filter 10 that removes foreign matter from the oil. The temperature control valve 9 reduces the flow rate of oil to the oil cooler 8 in response to a decrease in the temperature of the oil from the separator 5, thereby adjusting the temperature of the oil supplied to the working chamber of the compressor body 3.

[0015] The compressed air piping 7 is provided with a pressure regulating check valve 11, an aftercooler 12 arranged downstream of the pressure regulating check valve 11 to cool the compressed air, and a pressure sensor 13 arranged downstream of the aftercooler 12 to detect the pressure of the compressed air.

[0016] The compressor 1 of this embodiment further includes an inverter 15 that controls the power supplied from an external power source 14 to the electric motor 2 to control the rotation speed of the electric motor 2, a current sensor 16 that detects the current of the electric motor 2, a control device 17 that controls the operation of the compressor main body 3, and an operation / stop switch 18, a display 19, and an input device 20 connected to the control device 17.

[0017] The run / stop switch 18 outputs a run signal or a stop signal in response to its operation. The display 19 is, for example, a liquid crystal display. The input device 20 is, for example, a plurality of switches or a touch pad integrated with the display 19.

[0018] The control device 17 has a memory that stores programs and data, and a processor that executes processing based on the programs. In response to an operation signal from the on / off switch 18, the control device 17 drives the electric motor 2 via the inverter 15 to operate the compressor main body 3. In the normal operation mode, the control device 17 varies the rotation speed of the electric motor 2 via the inverter 15 between a predetermined upper limit value (e.g., 100% of the rated rotation speed) and a predetermined lower limit value (e.g., 30% of the rated rotation speed) so that the pressure detected by the pressure sensor 13 becomes a predetermined value. In response to a stop signal from the on / off switch 18, the control device 17 stops the electric motor 2 via the inverter 15 to stop the compressor main body 3.

[0019] A major feature of this embodiment is that, when the compressor main body 3 is restarted after being stopped for a predetermined time A (e.g., three months) or more, the control device 17 executes a diagnostic operation mode in which the load on the compressor main body 3 is reduced more than in the normal operation mode and the presence or absence of an abnormality is determined. The details of this operation will be described with reference to Fig. 2. Fig. 2 is a flowchart showing the processing contents of the control device 17 in this embodiment.

[0020] In step S1, the control device 17 determines whether or not a stop signal has been input from the run / stop switch 18 during operation of the compressor main body 3. If a stop signal has not been input from the run / stop switch 18, step S1 is repeated. On the other hand, if a stop signal has been input from the run / stop switch 18, the process proceeds to step S2.

[0021] In step S2, the control device 17 stops the compressor body 3 and measures the stop time of the compressor body 3 using a timer. Then, the process proceeds to step S3, where the control device 17 determines whether or not an operation signal has been input from the run / stop switch 18. If an operation signal has not been input from the run / stop switch 18, step S2 is repeated. That is, the control device 17 continues to measure the stop time of the compressor body 3. On the other hand, if an operation signal has been input from the run / stop switch 18, the process proceeds to step S4.

[0022] In step S4, the control device 17 determines whether the stop time of the compressor main body 3 is equal to or longer than time A. If the stop time of the compressor main body 3 is equal to or longer than time A, the process proceeds to step S5, and the control device 17 executes the diagnostic operation mode.

[0023] In the diagnostic operation mode, the control device 17 fixes the rotation speed of the electric motor 2 to a lower limit value via the inverter 15. This reduces the load on the compressor main body 3 compared to the normal operation mode. In the diagnostic operation mode, the control device 17 determines whether the starting torque of the compressor main body 3 is large based on the detection result of the current sensor 16 (for example, the increase or maximum value of the current when the electric motor 2 is started), thereby determining whether or not an abnormality exists.

[0024] For example, if the increase or maximum value of the current at the start of the electric motor 2 is less than a predetermined threshold, the control device 17 determines that the starting torque of the compressor body 3 is small and there is no abnormality. In this case, the process proceeds to step S7 via step S6, and the control device 17 transitions to the normal operation mode.

[0025] For example, if the increase or maximum value of the current at the start of the electric motor 2 is equal to or greater than a threshold value, the control device 17 determines that the starting torque of the compressor body 3 is large and abnormal. In this case, the process proceeds to step S8 via step S6, where the control device 17 stops the compressor body 3. The process also proceeds to step S9, where the control device 17 displays information prompting maintenance on the display 19. One possible cause of the increase in the starting torque of the compressor body 3 is an increase in oil viscosity due to oil deterioration. Therefore, the control device 17 may display information prompting maintenance on the display 19, such as information prompting replacement of the oil stored in the separator 5.

[0026] If it is determined in step S4 that the stop time of the compressor main body 3 is less than time A, the process proceeds to step S10. In step S10, the control device 17 determines whether the stop time of the compressor main body 3 is equal to or greater than time B (e.g., one month) that is set in advance so that the stop time is shorter than time A. If the stop time of the compressor main body 3 is less than time B, the process proceeds to step S7 described above, and the control device 17 executes the normal operation mode.

[0027] If, in step S10, the stop time of the compressor main body 3 is less than time A and equal to or greater than time B, the process proceeds to step S11. In step S11, the control device 17 displays a screen on the display device 19 for selecting whether or not to execute the diagnostic operation mode. Thereafter, the process proceeds to step S12, where the control device 17 determines whether or not execution of the diagnostic operation mode has been selected via the input device 20. If execution of the diagnostic operation mode has been selected, the process proceeds to the above-mentioned step S5, where the control device 17 executes the diagnostic operation mode. On the other hand, if it has been selected not to execute the diagnostic operation mode, the process proceeds to the above-mentioned step S7, where the control device 17 executes the normal operation mode.

[0028] As described above, the control device 17 of this embodiment executes the diagnostic operation mode when restarting the compressor main body 3 after the stop time of the compressor main body 3 is equal to or longer than time A. Furthermore, when restarting the compressor main body 3 after the stop time of the compressor main body 3 is shorter than time A and longer than time B, a screen for selecting whether to execute the diagnostic operation mode is displayed, and if execution of the diagnostic operation mode is selected, the diagnostic operation mode is executed. This makes it possible to evaluate whether an abnormality exists, i.e., whether maintenance is necessary. Therefore, maintenance can be performed as needed, thereby extending the life of the compressor 1. Furthermore, unnecessary maintenance can be reduced, thereby easing the burden on the user.

[0029] The diagnostic operation mode reduces the load on the compressor main body 3 compared to the normal operation mode. Therefore, even if an abnormality occurs, damage to the compressor main body 3, etc. can be suppressed. Therefore, from this perspective as well, the life of the compressor 1 can be extended.

[0030] A second embodiment of the present invention will be described with reference to the drawings. In this embodiment, parts equivalent to those in the first embodiment are given the same reference numerals, and descriptions thereof will be omitted as appropriate.

[0031] FIG. 3 is a diagram showing the configuration of the management system according to this embodiment.

[0032] The management system of this embodiment includes a compressor 1 having a compressor main body 3 and a control device 17, a management server 22 that communicates with the control device 17 via a communication network 21 and receives operation information (e.g., operation start information and shutdown start information) of the compressor main body 3 from the control device 17, and a user terminal 23 that communicates with the management server 22 via the communication network 21. Note that although the compressor 1 has a configuration similar to that of the first embodiment, the control device 17 does not measure the stop time of the compressor main body 3 (see step S2 in FIG. 2 described above) or determine whether to execute the diagnostic operation mode (see steps S4, S10 to S12 in FIG. 2 described above).

[0033] A major feature of this embodiment is that the management server 22 measures the stop time of the compressor main body 3 based on the operation information of the compressor main body 3. If the stop time of the compressor main body 3 is equal to or longer than time A, a command to execute the diagnostic operation mode when restarting the compressor main body 3 is transmitted to the control device 17. The details of this will be explained using Fig. 4. Fig. 4 is a flowchart showing the processing contents of the management server 22 in this embodiment.

[0034] In step S21, the management server 22 determines whether or not stop start information has been received from the control device 17. If stop start information has not been received from the control device 17, step S21 is repeated. On the other hand, if stop start information has been received from the control device 17, the management server 22 proceeds to step S22, where it initializes flag F to 0. Furthermore, the management server 22 proceeds to step S23, where it measures the stop time of the compressor main body 3 using a timer.

[0035] Thereafter, the process proceeds to step S24, where the management server 22 determines whether the stop time of the compressor main body 3 is equal to or greater than time A. If the stop time of the compressor main body 3 is less than time A, the process proceeds to step S25, where the management server 22 determines whether flag F=0. If flag F=0, the process proceeds to step S26, where the management server 22 determines whether the stop time of the compressor main body 3 is equal to or greater than time B. If the stop time of the compressor main body 3 is less than time B, the process proceeds to step S27, where the management server 22 determines whether operation start information has been received from the control device 17. If operation start information has been received from the control device 17, the management server 22 ends the process. On the other hand, if stop start information has not been received from the control device 17, the above-mentioned step S23 is repeated. That is, the management server 22 continues measuring the stop time of the compressor main body 3.

[0036] If it is determined in step S24 that the compressor main body 3 has been stopped for a period of time equal to or longer than time A, the process proceeds to step S28. In step S28, the management server 22 transmits to the control device 17 a command to execute the diagnostic operation mode when the compressor main body 3 is restarted.

[0037] If, in step S26, the stop time of the compressor main body 3 is less than time A and equal to or greater than time B, the process proceeds to step S29. In step S29, the management server 22 transmits a request (selection request) to the user terminal 23 as to whether or not to execute the diagnostic operation mode when restarting the compressor main body 3. Thereafter, the process proceeds to step S30, where the management server 22 determines whether or not a response to the effect that the diagnostic operation mode will be executed when restarting the compressor main body 3 has been received from the user terminal 23.

[0038] If a response to the effect that the diagnostic operation mode is to be executed when the compressor main body 3 is restarted is received, the process proceeds to step S28 described above. That is, the management server 22 transmits to the control device 17 a command to execute the diagnostic operation mode when the compressor main body 3 is restarted.

[0039] If in step S30 a response is not received indicating that the diagnostic operation mode will be executed when the compressor main body 3 is restarted (that is, for example, if a response is received indicating that the diagnostic operation mode will not be executed when the compressor main body 3 is restarted), the process proceeds to step S31. In step S31, the management server 22 sets flag F=1, and proceeds to the above-mentioned step S27. By setting flag F=1, steps S26, S28, S29, and S30 will not be executed thereafter, even if steps S23, S24, S25, and S27 are repeated.

[0040] As described above, in this embodiment, if the stop time of the compressor main body 3 is equal to or longer than time A, the management server 22 transmits to the control device 17 a command to execute the diagnostic operation mode when the compressor main body 3 is restarted. Furthermore, if the stop time of the compressor main body 3 is less than time A and equal to or longer than time B, the management server 22 transmits to the user terminal 23 a request as to whether or not to execute the diagnostic operation mode when the compressor main body 3 is restarted. If the management server 22 receives a response from the user terminal 23 indicating that the diagnostic operation mode will be executed when the compressor main body 3 is restarted, the management server 22 transmits to the control device 17 a command to execute the diagnostic operation mode when the compressor main body 3 is restarted. Upon receiving the above command, the control device 17 executes the diagnostic operation mode when the compressor main body 3 is restarted. This allows the control device 17 to evaluate whether an abnormality exists, i.e., whether maintenance is required. Therefore, maintenance can be performed as needed, thereby extending the life of the compressor 1. Furthermore, unnecessary maintenance can be reduced, thereby easing the burden on the user.

[0041] In the first and second embodiments, the control device 17 has been described with a fixed threshold value for comparison with the detection result of the current sensor 16 (e.g., the increase or maximum value of the current at the start of the electric motor 2). However, this is not limited to this, and the threshold value may be variable. Such a modification will be described with reference to FIG. 5 . FIG. 5 is a schematic diagram showing the configuration of the compressor 1 according to this modification. The compressor 1 according to this modification includes a temperature sensor 24 that detects the air temperature on the intake side of the compressor body 3 (e.g., around the compressor body 3) as a factor affecting the temperature of the oil supplied to the working chamber of the compressor body 3. The control device 17 stores a table showing the relationship between the air temperature and the threshold value (more specifically, the relationship in which the threshold value increases as the air temperature decreases) and selects a threshold value corresponding to the temperature detected by the temperature sensor 24. The control device 17 then compares the detection result of the current sensor 16 with the threshold value corresponding to the air temperature detected by the temperature sensor 24 to determine whether the starting torque of the compressor body 3 is large, thereby determining the presence or absence of an abnormality. This modification improves the accuracy of determining the presence or absence of an abnormality.

[0042] In the first and second embodiments, the control device 17 determines whether or not an abnormality exists by determining whether or not the starting torque of the compressor main body 3 is large based on the detection result of the current sensor 16, but the present invention is not limited to this. The control device 17 may also determine whether or not an abnormality exists by determining whether or not the starting torque of the compressor main body 3 is large based on the detection result of the pressure sensor 13 (for example, the rate of change of pressure).

[0043] Alternatively, the control device 17 may determine whether the operation of the compressor main body 3 is unstable based on the detection result of the current sensor 16, thereby determining whether an abnormality exists. For example, if the change pattern of the current of the electric motor 2 includes a sudden change, the control device 17 determines that the operation of the compressor main body 3 is unstable and that an abnormality exists. In this case, the control device 17 stops the compressor main body 3 and displays information prompting maintenance on the display 19. One possible cause of the unstable operation of the compressor main body 3 is the occurrence of rust inside the compressor main body 3. Therefore, the control device 17 displays information prompting maintenance, such as information prompting an inspection of the inside of the compressor main body 3, on the display 19. Even in such a modified example, the same effects as those of the first and second embodiments can be obtained.

[0044] Furthermore, in the first and second embodiments, the compressor 1 is a variable-speed machine that varies the rotation speed of the electric motor 2 (specifically, the control device 17 varies the rotation speed of the electric motor 2 between an upper limit and a lower limit via the inverter 15 in the normal operation mode, and fixes the rotation speed of the electric motor 2 to the lower limit via the inverter 15 in the diagnostic operation mode). However, the present invention is not limited to this. For example, as shown in FIG. 6 , the compressor 1 may be a fixed-speed machine that fixes the rotation speed of the electric motor 2 and includes an intake throttle valve 25 disposed on the intake side of the compressor body 3. In the normal operation mode, when the pressure detected by the pressure sensor 13 rises to a predetermined upper limit, the control device 17 switches the intake throttle valve 25 from an open state to a closed state, thereby switching from loaded operation to unloaded operation. When the pressure detected by the pressure sensor 13 falls to a predetermined lower limit, the control device 17 switches the intake throttle valve 25 from a closed state to an open state, thereby switching from unloaded operation to loaded operation. In the diagnostic operation mode, the control device 17 closes the suction throttle valve 25 to perform unloaded operation regardless of the pressure detected by the pressure sensor 13. This reduces the load on the compressor body 3 compared to the normal operation mode. Furthermore, in the diagnostic operation mode, the control device 17 may control the relay 26 disposed between the external power supply 14 and the electric motor 2 to perform unloaded operation intermittently (for example, at intervals of several seconds). This may further reduce the load on the compressor body 3. Even in this modified example, the same effects as those of the first and second embodiments can be obtained.

[0045] In the first and second embodiments, the compressor body 3 is a screw type having a pair of male and female screw rotors, but this is not limiting. The compressor body 3 may have, for example, one screw rotor and multiple gate rotors. The compressor body 3 may also be of a type other than the screw type.

[0046] 1...compressor, 3...compressor body, 5...separator, 6...oil piping, 19...display, 20...input device, 21...communication network, 22...management server, 23...user terminal.

Claims

1. A compressor comprising a compressor main body that compresses gas and a control device that controls the operation of the compressor main body, wherein the control device executes a diagnostic operation mode that determines whether or not there is an abnormality while reducing the load on the compressor main body more than in a normal operation mode when the compressor main body is restarted after being stopped for a predetermined first time period or longer.

2. A compressor according to claim 1, wherein the control device, when restarting the compressor main body in a state where the stop time of the compressor main body is equal to or longer than a second time preset so as to be shorter than the first time but shorter than the first time, displays a screen on a display for selecting whether or not to execute the diagnostic operation mode, and when execution of the diagnostic operation mode is selected by an input device, executes the diagnostic operation mode.

3. A compressor according to claim 1, characterized in that the control device, when determining that there is no abnormality in the diagnostic operation mode, transitions to the normal operation mode, and, when determining that there is an abnormality in the diagnostic operation mode, stops the compressor main body and displays information on a display prompting maintenance.

4. A compressor as claimed in claim 3, comprising a separator that separates oil from the compressed gas discharged from the compressor body and stores the separated oil, and an oil pipe that supplies the oil stored in the separator to the working chamber of the compressor body, and wherein the control device displays on the display, as the information to prompt for maintenance, information to prompt for replacement of the oil stored in the separator.

5. A management system comprising: a compressor having a compressor main body for compressing gas and a control device for controlling the operation of the compressor main body; and a management server that communicates with the control device via a communication network and receives operation information of the compressor main body from the control device, wherein the management server measures a stop time of the compressor main body based on the operation information of the compressor main body, and if the stop time of the compressor main body is equal to or longer than a predetermined first time, sends a command to the control device to execute a diagnostic operation mode that determines whether or not there is an abnormality while reducing the load on the compressor main body compared to a normal operation mode when the compressor main body is restarted.

6. A management system according to claim 5, further comprising a user terminal that communicates with the management server via the communication network, wherein the management server, when the stop time of the compressor main body is equal to or longer than a second time that is preset to be shorter than the first time and is shorter than the first time, sends to the user terminal a request as to whether or not to execute the diagnostic operation mode when the compressor main body is restarted, and when a response to the effect that the diagnostic operation mode will be executed when the compressor main body is restarted is received from the user terminal, sends to the control device a command to execute the diagnostic operation mode when the compressor main body is restarted.

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