Compressor

Abstract

To suppress a decrease in the operating rate of a compressor when a test run of a predetermined compressor unit is performed. [Solution] The compressor includes a plurality of compressor units, each having a compressor body that compresses gas and a motor that drives the compressor body, piping that connects the plurality of compressor units, and a control device that controls the plurality of compressor units. The control device stops operation of a compressor unit that satisfies an abnormal stop condition among the plurality of compressor units, and performs a test run of the compressor unit that satisfies the abnormal stop condition while continuing the number-controlled operation of the other compressor units.

Description

[Technical Field]

[0001] The present invention relates to a compressor. [Background technology]

[0002] There are known compressors that generate compressed gas used as a power source for pneumatic actuators of machine tools such as presses on production lines, and compressed gas used in pneumatic tools such as air blow guns and air drills. Patent Document 1 describes that a plurality of compressor units (compression modules) are connected in parallel, and while the system continues to operate, only the compressor unit that is the target of maintenance can be stopped to perform maintenance on that compressor unit. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-125772 Summary of the Invention [Problem to be solved by the invention]

[0004] In the technology described in Patent Document 1, when maintenance is performed on a compressor unit that has stopped due to the detection of an abnormality or the like, it is possible to continue operating other compressor units during the maintenance. However, Patent Document 1 does not disclose anything about the control of a compressor unit when a test run is performed to check whether the compressor unit that has stopped due to the detection of an abnormality or the like operates normally.

[0005] Generally, in a compressor equipped with multiple compressor units driven by the same power source, if a compressor unit fails, the operation of the failed compressor unit is stopped. After inspection or replacement, the failed compressor unit is test-run and then put back into normal operation. At this time, because all compressor units are supplied with power from the same power source, even if the operation of the compressor unit is stopped, its parts remain energized. Because replacing parts while they are energized may jeopardize the safety of workers, the entire compressor is often stopped to replace the faulty part.

[0006] However, depending on the type of failure, there may be cases where part replacement or manual inspection is not necessary. Even in such cases, there is room for improvement in terms of improving the operating rate of the compressor when the entire compressor is stopped. [Means for solving the problem]

[0007] According to one aspect of the present invention, a compressor includes a plurality of compressor units, each having a compressor main body that compresses gas and a motor that drives the compressor main body, piping that connects the plurality of compressor units, and a control device that controls the plurality of compressor units. The control device stops operation of a compressor unit that satisfies an abnormal stop condition among the plurality of compressor units, and performs a test run of the compressor unit that satisfies the abnormal stop condition while continuing the number-controlled operation of the other compressor units. [Effects of the Invention]

[0008] According to the present invention, when a predetermined compressor unit among a plurality of compressor units stops because it satisfies an abnormal stop condition, a test run of the predetermined compressor unit can be performed without interfering with the controlled number of units operation of the other compressor units. Because the test run of the predetermined compressor unit does not interfere with the controlled number of units operation of the other compressor units, the operating rate of the compressors can be improved. [Brief explanation of the drawings]

[0009] [Figure 1] FIG. 1 is a diagram showing the configuration of a compressor according to a first embodiment. [Figure 2] FIG. 2 is a schematic cross-sectional view of the compressor unit. [Figure 3] FIG. 3 is a diagram illustrating a method of operating the compressor. [Figure 4] FIG. 4 is a flowchart showing an example of the number control executed by the control device. [Figure 5] FIG. 5 is a flowchart showing the control for stopping the compression module when a stop condition is met during the number control. [Figure 6] FIG. 6 is a flowchart showing the contents of the test run of the compression module performed during the number of units control and the control for returning to the number of units control. [Figure 7] FIG. 7 is a flowchart showing the content of control when the test operation mode is set by the control device according to the modified example of the first embodiment. [Figure 8] FIG. 8 is a diagram showing the configuration of a compressor according to the second embodiment. [Figure 9] FIG. 9 is a diagram showing a target rotation speed table used for motor speed control by a control device according to a modified example of the second embodiment. [Figure 10] FIG. 10 is a diagram showing the configuration of a compressor according to the third embodiment. [Figure 11] FIG. 11 is a flowchart showing the control content when the test operation mode is set by the control device according to the third embodiment. [Figure 12] FIG. 12 is a diagram showing the relationship between the stop flag stored in the control device according to the first modification and whether or not the test run process can be performed. DETAILED DESCRIPTION OF THE INVENTION

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

[0011] First Embodiment Fig. 1 is a diagram showing the configuration of a compressor 10 according to a first embodiment of the present invention. As shown in Fig. 1, the compressor 10 according to the first embodiment of the present invention includes three compression modules 101A, 101B, and 101C that generate compressed gas such as compressed air, a main discharge pipe 105 to which the compressed gas discharged from the three compression modules 101A, 101B, and 101C is supplied, a second aftercooler 142 provided in the main discharge pipe 105, a third aftercooler 143 provided in the main discharge pipe 105 downstream of the second aftercooler 142, a dryer 144 provided in the main discharge pipe 105 downstream of the third aftercooler 143, a pressure sensor 131 provided in the main discharge pipe 105 downstream of the dryer 144, a control device (control board) 180 that controls the number of the three compression modules 101A, 101B, and 101C, and a package housing 11 that houses many of these components.

[0012] The multiple compression modules 101A, 101B, and 101C, the control device 180, and other electrical components housed in the package housing 11 are all supplied with power from the same power source (not shown) outside the package housing 11. The power supply path from the power source branches within the package housing 11 and is connected to the multiple compression modules 101A, 101B, and 101C, the control device 180, and other electrical components.

[0013] The three compression modules 101A, 101B, and 101C have the same configuration, and are therefore collectively referred to as compression module 101. Compression module 101 includes a compressor unit 100 having a compressor main body 110 and a motor 120, an electromagnetic switch 140 that switches between supplying and cutting off power to motor 120, a filter 150 that is connected to the suction port of compressor main body 110 and captures foreign matter, a module pipe 104 to which compressed gas discharged from compressor main body 110 is supplied, a check valve 151 provided in module pipe 104, and a first aftercooler 141 provided in module pipe 104 downstream of check valve 151. Check valve 151 allows gas to flow from compressor main body 110 toward first aftercooler 141 and prohibits gas from flowing from first aftercooler 141 toward compressor main body 110. Therefore, when the compression module 101 stops, the check valve 151 prevents compressed gas from flowing back from the main discharge pipe 105 to the compressor body 110. The module pipes 104 of the three compression modules 101 are connected to the same main discharge pipe 105.

[0014] The control device 180 is connected to the electromagnetic switch 140, the dryer 144, the operation panel 170, the communication device 190, the pressure sensor 131, the temperature sensor 132, and the ambient temperature sensor 133. The pressure sensor 131 detects the discharge pressure of the compressor 10 and outputs the detection result to the control device 180. The temperature sensor 132 detects the temperature of the compressor main body 110 and outputs the detection result to the control device 180. The ambient temperature sensor 133 detects the temperature around the compressor 10 and outputs the detection result to the control device 180.

[0015] The control device 180 is configured as a computer having a processor 181 such as a CPU (Central Processing Unit), MPU (Micro Processing Unit), or DSP (Digital Signal Processor), a non-volatile memory 182 such as a ROM (Read Only Memory), a flash memory, or a hard disk drive which is a magnetic storage device, a volatile memory 183 called RAM (Random Access Memory), an input interface, an output interface, and other peripheral circuits. The control device 180 may be configured as one computer or as multiple computers.

[0016] The nonvolatile memory 182 stores information such as programs and data required to execute various processes, including a control program for realizing the number control, etc. In other words, the nonvolatile memory 182 is a storage medium (storage device) from which a program for realizing the functions of this embodiment can be read. The processor 181 is a processing device that loads the program stored in the nonvolatile memory 182 into the volatile memory 183 and executes the program, and performs predetermined arithmetic processing on data taken in from the input interface, the nonvolatile memory 182, and the volatile memory 183 in accordance with the program.

[0017] The input interface converts signals input from the operation panel 170, communication device 190, pressure sensor 131, temperature sensor 132, ambient temperature sensor 133, electromagnetic switch 140, etc. into data that can be calculated by the processor 181. The output interface generates an output signal according to the calculation result by the processor 181, and outputs the signal to the electromagnetic switch 140, dryer 144, communication device 190, etc.

[0018] The control device 180 controls the first electromagnetic switch 140A to operate the first compressor unit 100A at a constant speed or to stop it. The control device 180 controls the second electromagnetic switch 140B to operate the second compressor unit 100B at a constant speed or to stop it. The control device 180 controls the third electromagnetic switch 140C to operate the third compressor unit 100C at a constant speed or to stop it. The electromagnetic switch 140 has an electromagnetic contactor and a thermal relay. The thermal relay detects an overcurrent flowing through the motor 120 and operates a contact, thereby stopping the motor 120. This prevents the motor 120 from burning out. The thermal relay outputs an overcurrent detection signal to the control device 180. The control device 180 detects an overcurrent in the motor 120 based on the detection signal from the thermal relay.

[0019] The compressed gas discharged from the compressor unit 100 passes through the check valve 151 and is supplied to the first aftercooler 141. The compressed gas cooled in the first aftercooler 141 is supplied to the main discharge pipe 105 through the module pipe 104. That is, the compressed gases discharged from the first to third compressor units 100A to 100C join at the main discharge pipe 105 and are supplied to the second aftercooler 142 and cooled. The compressed gas cooled in the second aftercooler 142 is supplied to the third aftercooler 143 and cooled. The compressed gas cooled in the third aftercooler 143 is supplied to the dryer 144. The dryer 144 dehumidifies the compressed gas by heat exchange with cooling air. That is, the dryer 144 is a heat exchanger that removes drain from the compressed gas. The compressed gas dehumidified by the dryer 144 is led from the outlet of the device to an external tank (not shown). Although not shown, the tank is connected to a pneumatic device via an output pipe, and supplies compressed gas to the pneumatic device by opening and closing a valve device provided on the output pipe. The pneumatic device may be, for example, a pneumatic actuator used in a machine tool, or an air tool such as an air blow gun or an air drill.

[0020] The configuration of the compressor unit 100 will be described with reference to FIG. 2. FIG. 2 is a cross-sectional schematic diagram of the compressor unit 100. As shown in FIG. 2, the compressor unit 100 includes a compressor main body 110 that compresses a gas such as air, a motor (electric motor) 120 that drives the compressor main body 110, and a cooling fan 130 that generates cooling air. The compressor main body 110 according to this embodiment compresses the gas using a compression method known as a scroll method. The compressor main body 110 includes a fixed scroll 111 and an orbiting scroll 112 that are arranged to face each other. A compression chamber 113 is formed between the fixed scroll 111 and the orbiting scroll 112, and the air in the compression chamber 113 is compressed by orbital motion.

[0021] The fixed scroll 111 has a disk-shaped end plate 111a, a spiral wrap portion 111b protruding from the end plate 111a toward the motor 120, and a plurality of cooling fins 111c protruding from the end plate 111a toward the opposite side to the motor 120.

[0022] The orbiting scroll 112 has a disk-shaped end plate 112a, a spiral wrap portion 112b protruding from the end plate 112a toward the fixed scroll 111 side, and a plurality of cooling fins 112c protruding from the end plate 112a toward the motor 120 side.

[0023] A tip seal 111d, which is a sealing member that seals between the tip surface of the wrap portion 111b and the end plate 112a of the orbiting scroll 112, is provided on the tip surface of the wrap portion 111b of the fixed scroll 111. A tip seal 112d, which is a sealing member that seals between the tip surface of the wrap portion 112b and the end plate 111a of the fixed scroll 111, is provided on the tip surface of the wrap portion 112b of the orbiting scroll 112.

[0024] The compression chamber 113 is formed between the wrap portion 111b of the fixed scroll 111 and the wrap portion 112b of the orbiting scroll 112, and is kept airtight by tip seals 111d, 112d. When the orbiting scroll 112 orbits in the forward direction, the compression chamber 113 moves from the radially outer side of the wrap portions 111b, 112b to the radially inner side, and is continuously reduced in size between the wrap portions 111b, 112b. As a result, gas supplied from the outside to the compression chamber 113 is compressed, and the compressed gas is discharged from a discharge port in the center of the wrap to the module piping 104 (see FIG. 1).

[0025] Motor 120 includes stator 121, which is a stator core with a stator coil attached thereto, rotor 122, which is disposed with a gap between it and stator 121, and shaft 123, which is fixed to rotor 122. Stator 121 and rotor 122 are housed in a motor housing, and shaft 123 is rotatably supported by bearings 124A and 124B, which are provided in the motor housing. When AC power is supplied from a power source (not shown) to the stator coil via electromagnetic switch 140, a rotating magnetic field is formed, and rotor 122 rotates together with shaft 123.

[0026] The motor 120 according to this embodiment is an axial gap motor, and is configured to coaxially drive the compressor body 110, but the type of the motor 120 is not limited to this. The motor 120 may be a radial gap type such as an inner rotor type or an outer rotor type, or a linear type.

[0027] The power of the motor 120 is transmitted to the orbiting scroll 112 and the cooling fan 130 via the shaft 123. When the motor 120 rotates, the orbiting scroll 112 rotates and compresses the gas, and the cooling fan 130 rotates, generating cooling air. The cooling air flows toward the motor 120 and the compressor body 110, cooling them. Note that a member (such as a duct) for guiding the cooling air generated by the cooling fan 130 may be provided so that the cooling air flows toward the cooling fins 111c of the fixed scroll 111 and the cooling fins 112c of the orbiting scroll 112.

[0028] A temperature sensor 132 for detecting the temperature of the compressor body 110 is attached to the cooling fins 111 c of the fixed scroll 111 .

[0029] A method of operating the compressor 10 will be described with reference to FIG. 3. As shown in FIG. 3, an operation panel 170 is attached to the front side of the package housing 11 of the compressor 10. The operation panel 170 has multiple display units 171a, 171b for informing the user of the status of the compressor 10. The display unit 171a is a digital display such as a liquid crystal display, and displays the discharge pressure of the compressor 10 detected by the pressure sensor 131, the operating time of the compressor 10, etc. The display unit 171a may be a 7-segment display having multiple 7-segment LEDs (light-emitting diodes). The multiple display units 171b are composed of LEDs or the like. The display unit 171b lights up or flashes in a predetermined color to inform the user of the operating status of the compressor 10, the selected control mode, whether or not there is an abnormality in the compressor 10, etc.

[0030] The operation panel 170 has a plurality of operation switches 172a to 172d that are operated by the user. The plurality of operation switches 172a to 172d include an operation switch 172a for instructing the start of operation, a stop switch 172b for instructing the stop of operation, a menu switch 172c for instructing a change of settings, and a display changeover switch 172d for changing the display content of the display unit 171a.

[0031] A user can start or stop the operation of the compressor 10, change settings, and switch the display content of the display unit 171a by operating the operation switches 172a to 172d of the operation panel 170. In this embodiment, the compressor 10 can be operated using an information terminal 90 that communicates wirelessly with the compressor 10. The information terminal 90 is any of various portable terminals that can be carried by the user, such as a smartphone, tablet, or wearable device.

[0032] A compressor application for monitoring the operating state of the compressor 10 and remotely operating the compressor 10 is installed in the information terminal 90. The compressor 10 and the information terminal 90 exchange information with each other via wireless communication. The communication device 190 (see FIG. 1) of the compressor 10 has a communication interface including a communication antenna having a sensitivity band within a predetermined frequency band.

[0033] Various methods can be adopted as a communication method between the compressor 10 and the information terminal 90. For example, the compressor 10 and the information terminal 90 may exchange information via a communication line 8, which is a wide area network. The communication line 8 may be the Internet, a mobile phone communication network (mobile communication network) such as 4G or 5G, a LAN (Local Area Network), or a WAN (Wide Area Network). Bluetooth (registered trademark) may be adopted as a short-range wireless communication method that enables direct exchange of information between the compressor 10 and the information terminal 90 without using the communication line 8. The short-range wireless communication method is not limited to Bluetooth, and communication methods such as Wi-Fi (registered trademark) and ZigBee (registered trademark) may also be adopted.

[0034] The information terminal 90 can control the operation of the compressor 10 by starting an installed compressor application and performing predetermined operations on a touch panel 93 of the information terminal 90. The information terminal 90 displays, in a status display area 91 of the touch panel 93, which functions as a display and input unit, display content similar to that displayed on the displays 171a and 171b of the operation panel 170. Furthermore, the information terminal 90 displays, in an operation area 92 of the touch panel 93, an operation switch 92a, a stop switch 92b, a menu switch 92c, and a display changeover switch 92d similar to the operation switches 172a to 172d of the operation panel 170. A user of the information terminal 90 can start or stop the operation of the compressor 10, change settings, and change the display content of the touch panel 93 by touching the operation switches 92a to 92d.

[0035] The information terminal 90 may be a dedicated information terminal that only operates and monitors the compressor 10. In this case, the operation panel 170 that is detachable from the package housing 11 can also be used as the information terminal 90. The operation method using the operation panel 170 is the same as the operation method using the information terminal 90. For this reason, the following will describe the control content of the control device 180 based on the operation of the operation panel 170, and will omit a description of the control content of the control device 180 based on the operation of the information terminal 90.

[0036] 1 and 4, the number control executed by the control device 180 will be described. The control device 180 shown in FIG. 1 has a function of storing the pressure detected by the pressure sensor 131, a function of measuring and storing the cumulative operating time of each compressor unit 100, and a function of operating and stopping the motor 120. The pressure sensor 131 is provided in the main discharge pipe 105 connected to a tank (not shown). In other words, the pressure detected by the pressure sensor 131 is approximately the same value as the pressure inside the tank.

[0037] The control device 180 outputs operation commands to the electromagnetic switches 140A-140C to operate the electromagnetic switches 140A-140C, thereby rotating the motors 120 of the compressor units 100A-100C at a constant speed. The control device 180 can operate the compression modules 101A-101C individually by outputting operation commands to each of the electromagnetic switches 140A-140C individually. For example, the control device 180 can select and operate one of the compression modules 101A-101C, select and operate two of the compression modules 101A-101C, or select and operate all of the compression modules 101A-101C.

[0038] In the unit number control, the control device 180 controls the number of operating compression modules 101 so that the pressure detected by the pressure sensor 131 is maintained within a pressure range from a lower limit pressure Pmin to an upper limit pressure Pmax. The upper limit pressure Pmax and the lower limit pressure Pmin are stored in advance in the nonvolatile memory 182. The upper limit pressure Pmax and the lower limit pressure Pmin stored in the nonvolatile memory 182 can be changed by operating the operation panel 170.

[0039] Fig. 4 is a flowchart showing an example of the number control executed by the control device 180. The processing of the flowchart shown in Fig. 4 is started when the operation switch 172a is operated, and after initial setting, is repeatedly executed at a predetermined sampling period Ts (for example, 200 ms).

[0040] In step S10, the control device 180 acquires the pressure P(t) detected by the pressure sensor 131, and proceeds to step S15. In step S15, the control device 180 determines whether the pressure P(t) acquired in step S10 is less than the lower limit pressure Pmin. If it is determined in step S15 that the pressure P(t) is less than the lower limit pressure Pmin, the process proceeds to step S20. In step S20, the control device 180 starts up all of the compression modules 101A to 101C, and ends the process shown in the flowchart of FIG. 4 for this calculation cycle. That is, the process proceeds to step S10 of the next calculation cycle, which is executed after the sampling period Ts has elapsed.

[0041] If it is determined in step S15 that the pressure P(t) is equal to or greater than the lower limit pressure Pmin, the process proceeds to step S25. In step S25, the control device 180 determines whether the pressure P(t) acquired in step S10 is equal to or greater than the upper limit pressure Pmax. If it is determined in step S25 that the pressure P(t) is equal to or greater than the upper limit pressure Pmax, the process proceeds to step S30. In step S30, the control device 180 stops all of the compression modules 101A to 101C, and ends the process shown in the flowchart of FIG. 4 for this calculation cycle. That is, the process proceeds to step S10 of the next calculation cycle, which is executed after the sampling period Ts has elapsed.

[0042] If it is determined in step S25 that the pressure P(t) is less than the upper limit pressure Pmax, the process proceeds to step S35. In step S35, the control device 180 calculates the pressure change rate K using the pressure P(t-1) acquired in step S10 of the previous calculation cycle and the pressure P(t) acquired in step S10 of the current calculation cycle, according to the following equation (1). K = (P(t) - P(t-1)) / Ts ... (1) The pressure change rate K is the rate of change of the discharge pressure of the compressor 10 over time.

[0043] When the calculation process of the pressure change rate K (step S35) is completed, the process proceeds to step S40. In step S40, the control device 180 determines whether the pressure change rate K calculated in step S35 is a negative value. If it is determined in step S40 that the pressure change rate K is a negative value, that is, if the discharge pressure is decreasing, the process proceeds to step S50. If it is determined in step S40 that the pressure change rate K is not a negative value, the process proceeds to step S45.

[0044] In step S50, the control device 180 calculates the predicted time Td from the current time until the lower limit pressure Pmin is reached by dividing the difference between the lower limit pressure Pmin and the current pressure P(t) obtained in step S10 by the pressure change rate K calculated in step S35, as shown in the following equation (2). Td=(Pmin-P(t)) / K …(2) When the calculation process of the predicted time Td (step S50) is completed, the process proceeds to step S60.

[0045] In step S60, the control device 180 determines whether the predicted time Td is less than a predetermined first time threshold Td1 (e.g., 2 seconds). The first time threshold Td0 is stored in the non-volatile memory 182. If it is determined in step S60 that the predicted time Td is less than the first time threshold Td0, the process proceeds to step S70. If it is determined in step S60 that the predicted time Td is equal to or greater than the first time threshold Td0, the process shown in the flowchart of FIG. 4 for this calculation cycle ends.

[0046] In step S70, the control device 180 determines to increase the number of operating compression modules 101 by one, and proceeds to step S80. In step S80, the control device 180 preferentially starts the compression module 101 that has the shortest cumulative operating time and is currently stopped, and ends the processing shown in the flowchart of FIG. 4 for this calculation cycle.

[0047] In step S45, the control device 180 determines whether the pressure change rate K calculated in step S35 is a positive value. If it is determined in step S45 that the pressure change rate K is a positive value, that is, if the discharge pressure is increasing, the process proceeds to step S55. If it is determined in step S45 that the pressure change rate K is not a positive value, that is, if the pressure change rate K is 0 and there is no pressure change, the process shown in the flowchart of FIG. 4 for this calculation cycle ends.

[0048] In step S55, the control device 180 calculates the predicted time Tu from the present time until the upper limit pressure Pmax is reached by dividing the difference between the upper limit pressure Pmax and the current pressure P(t) obtained in step S10 by the pressure change rate K calculated in step S35, as shown in the following equation (3). Tu = (Pmax - P(t)) / K ... (3) When the calculation process of the predicted time Tu (step S55) is completed, the process proceeds to step S65.

[0049] In step S65, the control device 180 determines whether the predicted time Tu is less than a predetermined second time threshold Tu0 (e.g., 5 seconds). The second time threshold Tu0 is stored in the non-volatile memory 182. If it is determined in step S65 that the predicted time Tu is less than the second time threshold Tu0, the process proceeds to step S75. If it is determined in step S65 that the predicted time Tu is equal to or greater than the second time threshold Tu0, the process shown in the flowchart of FIG. 4 for this calculation cycle ends.

[0050] In step S75, the control device 180 determines to decrease the number of operating compression modules 101 by one, and proceeds to step S85. In step S85, the control device 180 stops the compression module 101 with the longest cumulative operating time by priority, and ends the processing shown in the flowchart of FIG. 4 for this calculation cycle.

[0051] As described above, the control device 180 according to this embodiment controls the number of operating compression modules 101 based on the pressure P(t), which changes according to the amount of air used. The control device 180 reduces unnecessary power consumption by reducing the number of operating compression modules 101 before the pressure exceeds the upper limit pressure Pmax. Furthermore, the control device 180 increases the number of operating compression modules 101 before the pressure falls below the lower limit pressure Pmin, thereby appropriately supplying the required amount of air to the pneumatic equipment. The control device 180 prioritizes activation of compression modules 101 with a short cumulative operating time and prioritizes deactivation of compression modules 101 with a long cumulative operating time. This allows the cumulative operating time of each compression module 101 to be averaged. As a result, by performing maintenance on each compression module 101 in parallel at the same time, the time during which the compressor 10 is not in operation can be minimized.

[0052] The process flow for controlling the number of units is not limited to the example shown in Fig. 4. The control of the number of units may be any control that can generate a target pressure using a plurality of compression modules 101, and various modes of the process flow may be adopted. For example, the control device 180 may execute control of the number of units by repeatedly performing a process of simultaneously starting up a plurality of compression modules 101 that are the subject of the control of the number of units when the pressure P(t) detected by the pressure sensor 131 falls below the lower limit pressure Pmin, and a process of simultaneously stopping a plurality of compression modules 101 that are the subject of the control of the number of units when the pressure P(t) detected by the pressure sensor 131 becomes equal to or greater than the upper limit pressure Pmax.

[0053] The control device 180 individually determines whether or not a plurality of compression modules 101 are abnormal. If the control device 180 determines that a compression module 101 is abnormal, it sets a stop flag for the compression module 101 determined to be abnormal. The control device 180 continues the number control for the compression modules 101 for which the stop flag is not set, while executing an exclusion process to stop the compression modules 101 for which the stop flag is set and exclude them from the number control targets. In this way, by the control device 180 stopping the compression modules 101 determined to be abnormal and excluding them from the number control targets, subsequent wear of the compression modules 101 (deterioration of the tip seals 111d and 112d, damage to the check valve 151, etc.) can be prevented. Note that in the exclusion process, the control device 180 may stop the compression modules 101 for which the stop flag is set and then exclude them from the number control targets, or may exclude the compression modules 101 for which the stop flag is set from the number control targets and then stop them.

[0054] Furthermore, the control device 180 causes the display units 171a and 171b to display information about the compression modules 101 for which the stop flag is set. The compression modules 101 for which the stop flag is set, i.e., the compression modules 101 that have been stopped due to the setting of the stop flag, cannot return to the number control unless the stop flag is released.

[0055] The display mode of the display units 171a and 171b allows the user to know that the compression module 101 has stopped due to the detection of an abnormality, etc., and the reason for the stop (for example, the nature of the abnormality). Abnormalities detected by the control device 180 according to this embodiment include temperature abnormalities and current abnormalities. The control device 180 according to this embodiment sets a stop flag not only when an abnormality is detected, but also when the cumulative operating time of the compression module 101 reaches the maintenance time. Below, the conditions for stopping the compression module 101 while the number control is being executed (hereinafter also referred to as stop conditions) will be described in detail.

[0056] The control device 180 determines whether the following first to third stop conditions are met. If any of the first to third stop conditions is met, the control device 180 sets a stop flag and stops the compression module 101 for which the stop flag is set. (First stop condition) The temperature difference ΔT, which is the difference between the temperature T1 of the compressor body 110 and the ambient temperature T2 of the compressor 10, is equal to or greater than the temperature threshold T0. In other words, a temperature abnormality has occurred. (Second stop condition) An overcurrent is detected by the thermal relay, i.e., a current abnormality occurs. (Third stop condition) The cumulative operating time has reached the maintenance time. As described above, the plurality of stop conditions (first to third stop conditions) include the stop conditions (first and second stop conditions) that are met when the compressor unit 100 has an abnormality.

[0057] The process by the control device 180 to determine whether the first stop condition is met is synonymous with the process to determine whether a temperature abnormality exists. When the tip seals 111d, 112d deteriorate over time, compressed gas leaks from the compression chamber 113 through the tip seals 111d, 112d, and is again sucked into the compression chamber 113 and compressed, causing the temperature of the compressed gas to rise above normal. In other words, when the tip seals 111d, 112d deteriorate and a seal leak occurs, the control device 180 detects a temperature abnormality.

[0058] In this embodiment, an example is described in which it is determined whether or not a temperature abnormality has occurred based on the difference between the temperature of the compressor body 110 and the ambient temperature of the compressor 10. However, it may also be determined whether or not a temperature abnormality has occurred based only on the temperature of the compressor body 110. However, the temperature of the compressor body 110 is affected by the environment in which the compressor 10 is installed. For example, if the temperature of the room in which the compressor 10 is installed is high, the temperature of the compressor body 110 will be higher than if the room temperature is low. For this reason, by determining whether or not a temperature abnormality has occurred based on the difference between the ambient temperature of the compressor 10 (room temperature) and the temperature of the compressor body 110, as in this embodiment, it is possible to accurately detect a temperature abnormality.

[0059] In addition, in this embodiment, an example is described in which the temperature sensor 132 is installed on the cooling fin 111c, but the temperature sensor 132 may be installed in a location other than the cooling fin 111c as long as it can detect the temperature of a part that has a certain relationship with the temperature inside the compression chamber 113.

[0060] The process by the control device 180 to determine whether the second stop condition is met is synonymous with the process to determine whether there is a current abnormality. As described above, when the tip seals 111d, 112d deteriorate over time, compressed gas leaks from the compression chamber 113 through the tip seals 111d, 112d and is again drawn into the compression chamber 113 and compressed. When compressed gas flows from the high-pressure compression chamber 113 to the low-pressure compression chamber 113, the force required to drive the compressor main body 110 increases. In this case, the motor drive current increases above normal. In other words, when the tip seals 111d, 112d deteriorate and a seal leak occurs, the control device 180 detects a current abnormality.

[0061] Furthermore, if the wrap portions 111b, 112b are deformed due to aging or the like, the wrap portion 111b of the fixed scroll 111 and the wrap portion 112b of the orbiting scroll 112 may come into contact with each other. When the wrap portions come into contact with each other, a greater force is required to drive the compressor body 110. In this case, the motor drive current increases compared to normal. In other words, if the wrap portions 111b, 112b deteriorate and come into contact with each other, the control device 180 detects a current abnormality.

[0062] Furthermore, when the bearings 124A, 124B deteriorate over time, the force required to drive the compressor body 110 increases, causing the motor drive current to rise above normal. In other words, when the bearings 124A, 124B deteriorate, the control device 180 detects a current abnormality.

[0063] In this embodiment, an example is described in which a current abnormality is detected based on the operation of a thermal relay provided in the electromagnetic switch 140. However, a current sensor may be used to detect the current in the power line connecting the electromagnetic switch 140 and the motor 120, and a current abnormality may be detected based on the detection result. However, providing a current sensor increases the cost of the compressor 10. For this reason, by adopting a configuration in which a current abnormality is detected based on the operation of the thermal relay of the electromagnetic switch 140, as in this embodiment, the cost of the compressor 10 can be reduced.

[0064] When the first stop condition is met, the control device 180 sets the temperature abnormality stop flag Ft(j) as the stop flag (Ft(j)=1). When the second stop condition is met, the control device 180 sets the current abnormality stop flag Fi(j) as the stop flag (Fi(j)=1). When the third stop condition is met, the control device 180 sets the maintenance stop flag Fm(j) as the stop flag (Fm(j)=1). Note that j is a number from 1 to 3 for identifying the first to third compression modules 101A to 101C. For example, the stop flag associated with the first compression module 101A is j=1, the stop flag associated with the second compression module 101B is j=2, and the stop flag set for the third compression module 101C is j=3.

[0065] The control device 180 calculates the difference (hereinafter, temperature difference) ΔT(j) between the temperature T1(j) of the compressor main body 110 detected by the temperature sensor 132 and the temperature T2 of the surroundings of the compressor 10 detected by the ambient temperature sensor 133 (ΔT(j) = T1(j) - T2). The control device 180 calculates the temperature difference ΔT(j) for each compression module 101. That is, the control device 180 calculates the difference between the temperature T1(1) detected by the first temperature sensor 132A and the temperature T2 detected by the ambient temperature sensor 133 as the temperature difference ΔT(1) of the first compression module 101A. Similarly, the control device 180 calculates the difference between the temperature T1(2) detected by the second temperature sensor 132B and the temperature T2 detected by the ambient temperature sensor 133 as the temperature difference ΔT(2) of the second compression module 101B. Furthermore, the control device 180 calculates the difference between the temperature T1(3) detected by the third temperature sensor 132C and the temperature T2 detected by the ambient temperature sensor 133 as the temperature difference ΔT(3) of the third compression module 101C.

[0066] The control device 180 determines whether the temperature difference ΔT(j) of each compression module 101 is equal to or greater than the temperature threshold value T0. The temperature threshold value T0 is stored in advance in the non-volatile memory 182. If the temperature difference ΔT(j) is less than the temperature threshold value T0, the control device 180 determines that the first stop condition is not met and keeps the temperature abnormality stop flag Ft(j) in an unset state (Ft(j)=0). If the temperature difference ΔT is equal to or greater than the temperature threshold value T0, the control device 180 determines that the first stop condition is met and sets the temperature abnormality stop flag Ft(j) (Ft(j)=1). The temperature abnormality stop flag Ft(j) is a stop flag indicating that a temperature abnormality has been detected in the compressor unit 100 of the compression module 101, and is set in association with the compression module 101 for which it has been determined that the first stop condition is met.

[0067] The control device 180 determines whether an overcurrent has been detected by the thermal relay of the electromagnetic switch 140 based on an overcurrent detection signal from the thermal relay of the electromagnetic switch 140. If an overcurrent has not been detected by the thermal relay, the control device 180 determines that the second stop condition is not met and keeps the current abnormality stop flag Fi(j) in an unset state (Fi(j)=0). If an overcurrent has been detected by the thermal relay, the control device 180 determines that the second stop condition is met and sets the current abnormality stop flag Fi(j) (Fi(j)=1). The current abnormality stop flag Fi(j) is a stop flag indicating that an overcurrent has been detected in the compressor unit 100 of the compression module 101, and is set in association with the compression module 101 for which it has been determined that the second stop condition is met.

[0068] The control device 180 determines whether the cumulative operation time to has reached the maintenance time to0. The maintenance time to0 is stored in advance in the non-volatile memory 182. If the cumulative operation time to is less than the maintenance time to0, the control device 180 determines that the third stop condition is not met and keeps the maintenance stop flag Fm(j) in an unset state (Fm(j)=0). If the cumulative operation time to is equal to or greater than the maintenance time to0, the control device 180 determines that the third stop condition is met and sets the maintenance stop flag Fm(j) (Fm(j)=1). The maintenance stop flag Fm(j) is a stop flag indicating that the maintenance time has been reached, and is set in association with the compression module 101 for which it has been determined that the third stop condition is met.

[0069] As described above, a compression module 101 for which a stop flag has been set will not be incorporated into the unit count control unless the stop flag is cleared. The control device 180 performs a test run of the stopped compression module 101 based on an operation command from the operation panel 170. If the user confirms that there are no abnormalities during the test run, the user performs an operation to clear the stop flag. This clears the stop flag, allowing the compression module 101 that has undergone the test run to return to the unit count control.

[0070] The control device 180 according to this embodiment continues to control the number of compression modules 101 for which no stop flag is set, while restarting the compression modules 101 for which a stop flag is set, and executes a test run process in which the compression modules 101 are operated for a predetermined period of time. In other words, the control device 180 starts up the compression modules 101 that are not subject to the number control, while continuing to control the number of compression modules 101 that are subject to the number control. For example, the control device 180 continues to control the number of compression modules 101 for which it is determined that there is no temperature abnormality, while restarting the compression modules 101 for which it is determined that there is a temperature abnormality.

[0071] In addition, the control device 180 makes it impossible to cancel the setting of the stop flag if the trial run processing has not been completed after the exclusion processing has been executed, and makes it possible to cancel the setting of the stop flag if the trial run processing has been completed after the exclusion processing has been executed.

[0072] The control for stopping the compression module 101 when a stop condition is met during the number control will be described in detail below with reference to Fig. 5. As described above, when the operation switch 172a is operated, the number control of the control device 180 (step S1 in Fig. 5, flowchart in Fig. 4) is executed. As shown in Fig. 5, while the number control (step S1) is being executed, the control device 180 repeatedly executes the processes of steps S105 to S190 at a predetermined sampling period.

[0073] In step S105, the control device 180 executes a process of determining whether the first to third stop conditions are satisfied. If the control device 180 determines that the stop conditions are satisfied, it sets a stop flag associated with the compression module 101 for which it has determined that the stop condition is satisfied. For example, if the control device 180 determines that the first stop condition is satisfied for the first compression module 101A, it switches the temperature abnormality stop flag Ft(1) of the first compression module 101A from the unset state (off) to the set state (on) (Ft(1)=0→Ft(1)=1). Also, for example, if the control device 180 determines that the second stop condition is satisfied for the second compression module 101B, it switches the current abnormality stop flag Fi(2) of the second compression module 101B from the unset state (off) to the set state (on) (Fi(2)=0→Fi(2)=1). Also, for example, when the control device 180 determines that the third stop condition is met for the third compression module 101C, it switches the maintenance stop flag Fm(3) of the third compression module 101C from a non-set state (off) to a set state (on) (Fm(3)=0→Fm(3)=1).

[0074] When the stop determination process (step S105) is completed, the process proceeds to step S110. In step S110, the control device 180 determines whether or not a stop flag has been set in at least one of the multiple compression modules 101. If it is determined in step S110 that a stop flag has not been set in all of the multiple compression modules 101, the process proceeds to step S190. If it is determined in step S110 that a stop flag has been set in at least one of the multiple compression modules 101, the process proceeds to step S115.

[0075] In step S115, the control device 180 executes a stop process to stop the compression module 101 for which the stop flag is set, and then the process proceeds to step S120.

[0076] In step S120, the control device 180 executes an exclusion process to exclude the compression modules 101 for which the stop flag is set from the number control, and then the process proceeds to step S190.

[0077] In step S190, the control device 180 determines whether the stop switch 172b has been operated. If it is determined in step S190 that the stop switch 172b has not been operated, the process returns to step S105. If it is determined in step S190 that the stop switch 172b has been operated, the process proceeds to step S195. In step S195, the control device 180 stops all compression modules 101, and ends the process shown in the flowchart of FIG. 5.

[0078] The control of the test run of the compression module 101 performed during the number control and the return to the number control will be described in detail below with reference to FIG. 6. When an operation to start a test run is performed on the operation panel 170, the control device 180 sets the test run mode. The process shown in FIG. 6 is executed when the test run mode is set. As shown in FIG. 6, when the test run mode is set, in step S130, the control device 180 displays a selection operation screen on the display unit 171a that prompts the user to select the compression module 101 to perform the test run. The selection operation screen is, for example, a screen that displays the number (e.g., 1 to 3) of the compression module 101 to perform the test run. Each time the display changeover switch 172d is operated, the number of the compression module 101 on the display unit 171a is changed. When the menu switch 172c is operated while the number representing the compression module 101 to perform the test run is displayed, the control device 180 selects the compression module 101 corresponding to the number displayed on the test run main unit selection screen as the compression module 101 to perform the test run. It is not possible to perform a test run on a compression module 101 that is not stopped.

[0079] In step S130, when the compression module 101 to be subjected to the test run is selected, the process proceeds to step S135. In step S135, the control device 180 executes a test run process in which the motor 120 of the compression module 101 selected in step S130 is supplied with power via the electromagnetic switch 140 to operate the motor 120 at a constant speed for a predetermined time tp. The predetermined time tp may be set to a value ranging from several seconds to several minutes, as long as it is long enough to confirm an abnormality in the compression module 101. Preferably, the predetermined time tp is initially set to a few seconds, and the predetermined time tp can be changed via the operation panel 170. Setting the test run time to a few seconds can prevent further wear (deterioration) of the compression module 101. Furthermore, by making the predetermined time tp changeable via the operation panel 170, the predetermined time tp can be changed to a longer time than the initial setting as needed, thereby improving the accuracy of abnormality confirmation.

[0080] In step S135, the control device 180 may stop the operating compression modules 101 for a predetermined time tp by controlling the number of compression modules in order to suppress changes in the flow rate of gas discharged from the compressor 10. For example, when two compression modules, the first compression module 101A and the second compression module 101B, are in operation and a test run is being performed on the third compression module 101C for which a stop flag is set, the control device 180 may start the third compression module 101C and stop the operation of the first compression module 101A or the second compression module 101B.

[0081] When the test run process (step S135) is completed, the process proceeds to step S140. In step S140, the control device 180 causes the display unit 171a to display a flag release selection screen. The flag release selection screen is a screen that prompts the user to select whether or not to release the stop flag, for example. Each time the display changeover switch 172d is operated, the display of "y" and "n" is switched as the selection content displayed on the flag release selection screen.

[0082] In step S140, the control device 180 determines whether an operation to cancel the stop flag has been performed. In step S140, if the menu switch 172c is operated while "y" is displayed on the display unit 171a, the control device 180 determines that an operation to cancel the stop flag has been performed, and proceeds to step S145. In step S140, if the menu switch 172c is operated while "n" is displayed on the display unit 171a, the control device 180 ends the test run mode without canceling the stop flag of the compression module 101 that has performed the test run. Note that the method of operation to cancel the stop flag is not limited to this.

[0083] In step S145, the control device 180 clears the stop flag of the compression module 101 that has performed the test run and proceeds to step S150. In step S150, the control device 180 includes the compression module 101 whose stop flag was cleared in step S145 in the number of units controlled and ends the test run mode. During the test run of the compression module 101 whose stop flag was set, the compression modules 101 whose stop flag was not set continue to operate under number-controlled operation. In other words, in step S150, the compression module 101 whose stop flag was cleared returns to number-controlled operation.

[0084] According to the above-described embodiment, the following advantageous effects are achieved.

[0085] (1) The compressor 10 includes a compressor unit 100 having a compressor main body 110 that compresses gas and a motor 120 that drives the compressor main body 110, and a control device 180 that controls the number of compressor units 100. The compressor units 100 are connected to the same pipe (main discharge pipe 105). The control device 180 continues to control the number of compressor units 100 that are the subject of the number control, while starting up compressor units 100 that are not the subject of the number control.

[0086] According to this configuration, when a predetermined compressor unit 100 (e.g., the third compressor unit 100C) stops due to the detection of an abnormality or the like, the predetermined compressor unit (e.g., the third compressor unit 100C) can be started up and test run without interfering with the number control operation of the other compressor units (e.g., the first and second compressor units 100A, 100B), and after confirming that it is normal, can be incorporated into the number control operation. Because the test run of the predetermined compressor unit 100 does not interfere with the number control operation of the other compressor units 100, the availability rate of the compressors 10 can be improved.

[0087] (2) The control device 180 determines whether or not there is an abnormality in the multiple compressor units 100. The control device 180 stops the compressor units 100 determined to have an abnormality and excludes them from the number control, and restarts the compressor units 100 determined to have an abnormality while continuing the number control of the compressor units 100 determined not to have an abnormality.

[0088] This configuration allows a compressor unit 100 determined to have an abnormality to be restarted and tested for operation without interrupting the number-of-compressor-units control operation of a compressor unit 100 determined to be normal. After confirming normal operation, the compressor unit 100 can be incorporated into the number-of-compressor-units control operation. Therefore, a compressor unit 100 determined to have an abnormality due to a false detection can be quickly returned to the number-of-compressor-units control operation. For example, when the door of a room in which a compressor 10 is installed opens and outside air flows into the room, the ambient temperature T2 may suddenly drop. The rate of decrease in the temperature T1(j) of the compressor body 110 at this time is smaller than the rate of decrease in the ambient temperature T2. In other words, the absolute value of the time rate of change of the temperature T1(j) of the compressor body 110 is smaller than the absolute value of the time rate of change of the ambient temperature T2. As a result, the temperature difference ΔT may exceed the temperature threshold T0, resulting in a determination that a temperature abnormality exists.

[0089] In this way, even if there is no leakage from the tip seals 111d, 112d of the compressor body 110, a false temperature detection may occur. If the entire compressor 10 is stopped in such a case, the operating rate of the compressor 10 will decrease. Therefore, the user performs a trial run to determine whether the temperature detection is a false detection. The user determines whether the temperature detection is a false detection by measuring the temperature of the compressor body 110 with a temporary thermometer or by displaying the detection value of the permanent temperature sensor 132 on the display unit 171a.

[0090] If the user determines that the temperature abnormality was a false detection, the user clears the stop flag (temperature abnormality stop flag). This allows the compressor unit 100 that was stopped due to the false detection to quickly return to the unit count control. Furthermore, while a series of processes are being executed, such as stopping a specific compressor unit 100 due to the false detection, performing a test run of that compressor unit 100, and returning that compressor unit 100 to the unit count control, the other compressor units 100 continue to operate under the unit count control. This minimizes the decrease in the operating rate of the compressors 10. In other words, according to this embodiment, the decrease in the operating rate of the compressors 10 can be suppressed compared to when all compressors 10 are stopped before test run.

[0091] (3) The current abnormality may be caused by a compressed gas leak due to deterioration of the tip seals 111d and 112d of the compressor body 110, contact between the wrap portions 111b and 112b due to deformation of the wrap portions 111b and 112b, or deterioration of the bearings 124A and 124B. Therefore, the user performs a test run to confirm the cause of the current abnormality. The user listens for abnormal noise caused by contact between the wrap portions or abnormal noise from the bearings 124A and 124B. The user also measures the temperature of the compressor body 110 with a temporary thermometer and displays the detected value of the permanent temperature sensor 132 on the display unit 171a. The user can identify the cause of the current abnormality based on the sound of the compressor unit 100 during the test run and the temperature of the compressor body 110. The user then stops the compressor 10 and performs maintenance to eliminate the cause of the current abnormality. In this manner, in this embodiment, while a test run is being performed to identify the cause of the current abnormality in a specific compressor unit 100, the number of other compressor units 100 can be continuously controlled, thereby improving the operating rate of the compressor 10.

[0092] (4) When the control device 180 determines that a compressor unit 100 has an abnormality, it sets a stop flag for the compressor unit 100 determined to have an abnormality. The control device 180 continues the unit count control for the compressor units 100 for which the stop flag is not set, while executing exclusion processing to stop the compressor units 100 for which the stop flag is set and exclude them from the unit count control targets. The control device 180 executes trial run processing to restart the compressor units 100 for which the stop flag is set, while continuing the unit count control for the compressor units 100 for which the stop flag is not set. After the exclusion processing is executed, if the trial run processing is not completed, it is not possible to cancel the setting of the stop flag, but if the trial run processing is completed after the exclusion processing is executed, it is possible to cancel the setting of the stop flag.

[0093] If the stop flag could be cleared without completing the test run process for a given compressor unit 100, the following problem could arise. In fact, if a temperature abnormality occurs due to a leak in the tip seals 111d and 112d, causing the compressor unit 100 to stop, the user may mistakenly clear the stop flag. This could result in further deterioration of the tip seals 111d and 112d. In contrast, in this embodiment, the stop flag cannot be cleared unless the test run process is completed. Therefore, the above-mentioned problem does not occur. In other words, the user can perform a test run to determine whether the temperature abnormality is a false positive. If the temperature abnormality is not a false positive, the user can stop the compressor 10 and take appropriate action, such as replacing the tip seals 111d and 112d of the compressor unit 100.

[0094] (5) When the control device 180 is performing the number control of the compressor units 100 that are subject to the number control and the stop flag of a compressor unit 100 that is not subject to the number control is cleared, the control device 180 continues the number control while including the compressor unit 100 whose stop flag has been cleared as a target for the number control. With this configuration, the compressor unit 100 that has undergone a test run can be returned to the number control without stopping the compressor 10. Therefore, according to this embodiment, the operating rate of the compressor 10 can be improved compared to when the compressor 10 is stopped when returning the compressor unit 100 to the number control.

[0095] (6) The compressor 10 includes an electromagnetic switch 140 that switches between supplying and cutting off power to the motor 120. The control device 180 supplies power to the motor 120 using the electromagnetic switch 140, and then operates the compressor units 100 that are not subject to the number control at a constant speed for a predetermined time tp and stops them. This configuration limits the operating time of the test run to the predetermined time tp. In other words, the test run is prevented from being continued beyond the predetermined time tp. This prevents damage to the compression module 101 that would otherwise occur if the test run were performed over a long period of time.

[0096] <Modification of the first embodiment> In the first embodiment, an example was described in which, when there are three compressor units 100 and one compressor unit 100 that is not subject to the unit count control, a test run is performed on that compressor unit 100, and the unit count control is resumed after the stop flag is cleared. However, the present invention is not limited to this. For example, the present invention may be applied to a compressor 10 that includes four or more compressor units 100 and a compressor 10 that includes only two compressor units 100. However, in the case of a compressor 10 that includes only two compressor units 100, if one of the two compressor units 100 is stopped due to a stop flag, only one compressor unit 100 that can operate normally remains. In this case, the remaining compressor unit 100 is not additionally started by the processing of steps S70 and S80 in FIG. 4, but the processing flow for the unit count control shown in FIG. 4 itself remains the same. That is, in a compressor 100 having two or more compressor units 100, the control device 180 performs the unit number control shown in FIG. 4 regardless of the number of compressor units 100 that are stopped.

[0097] Furthermore, when there are multiple compressor units 100 that are not subject to unit count control, a test run may be performed on the compressor units 100 that are not subject to unit count control, and the unit count control may be restored after the stop flag is cleared. Note that when there are multiple compressor units 100 that are not subject to unit count control, it is preferable to perform a test run on each one. If test runs are performed on multiple compressor units 100 at the same time, it may be difficult to check for abnormalities.

[0098] Fig. 7 is a flowchart similar to Fig. 6, showing the details of control when the test operation mode is set by the control device 180 according to the modified example of the first embodiment. In the flowchart of Fig. 7, the process of step S160 is added after the process of step S150 in the flowchart of Fig. 6. As shown in Fig. 7, when the process of including the compression module 101 whose stop flag has been cleared as a target for number control is completed in step S150, the process proceeds to step S160.

[0099] In step S160, the control device 180 determines whether the termination condition for the test operation mode has been met. If the stop flag is set for any of the multiple compression modules 101, the control device 180 determines that the termination condition for the test operation mode has not been met, and returns to step S130. If the stop flag is not set for any of the multiple compression modules 101, the control device 180 determines that the termination condition for the test operation mode has been met, and ends the processing shown in the flowchart of FIG. 7. Note that in step S130, the control device 180 selects only one compression module 101 for which the stop flag is set, and proceeds to step S135.

[0100] As described above, in this modification, when there are multiple compressor units 100 that are not subject to the unit count control, the control device 180 drives the multiple compressor units 100 that are not subject to the unit count control one by one. Therefore, when there are multiple compressor units 100 for which the stop flag is set, the user selects the compressor units 100 to perform a test run one by one, and performs the test run one by one. This makes it possible to appropriately check whether or not there is an abnormality in the compressor units 100 based on, for example, the sound of the compressor units 100 during the test run.

[0101] Second Embodiment A compressor 20 according to a second embodiment of the present invention will be described with reference to Figures 8 and 9. Note that components that are the same as or equivalent to those described in the first embodiment are given the same reference numerals, and differences will be mainly described. Figure 8 is a diagram similar to Figure 1, and shows the configuration of a compressor 20 according to the second embodiment.

[0102] The compressor 10 according to the first embodiment is configured such that the motor 120 is controlled to rotate at a constant speed by an electromagnetic switch 140 (see FIG. 1). In contrast, the compressor 20 according to the second embodiment is configured such that the rotation speed of the motor 120 is controlled by an inverter 240, as shown in FIG. 8. The compressor 20 according to the second embodiment will be described in detail below.

[0103] The compressor 20 according to the second embodiment has substantially the same configuration as that of the first embodiment, but instead of the electromagnetic switch 140 described in the first embodiment, an inverter 240 is provided that supplies power from a power source to the motor 120. The inverter 240A of the first compression module 101A, the inverter 240B of the second compression module 101B, and the inverter 240C of the third compression module 101C have the same configuration.

[0104] The control device 280 controls the rotation speed of the motor 120 using the inverter 240 so that the value of the discharge pressure (i.e., the pressure detected by the pressure sensor 131), which changes depending on the amount of compressed gas used, becomes a predetermined target pressure value. The control device 280 according to this embodiment converts the current frequency (e.g., 60 Hz) of the commercial power supply into a target current frequency based on the detection result of the pressure sensor 131, and supplies this to the motor 120, thereby controlling the rotation speed of the motor 120.

[0105] The inverter 240 has multiple switching elements, a voltage sensor 235, and a current sensor 236. The inverter 240 has a well-known configuration including a converter circuit, an inverter circuit, and a smoothing capacitor. The inverter circuit converts the DC current supplied from the converter circuit into AC current using switching elements. The voltage sensor 235 detects the DC voltage between a pair of power lines (DC buses) connecting the converter circuit and the inverter circuit, and outputs a voltage signal representing the detection result to the control device 280. The current sensor 236 is provided on a conductive member connecting the inverter circuit and the armature windings of each phase of the motor (three-phase AC motor) 120. The current sensor 236 detects the current supplied to the motor 120 and outputs a current signal representing the detection result to the control device 280.

[0106] In the first embodiment, the compressor unit 100 is operated at a constant speed, maintaining a constant discharge flow rate regardless of the amount of compressed gas used. In contrast, in the second embodiment, the inverter 240 can be used to control the motor rotation speed according to the amount of compressed gas used, thereby adjusting the discharge flow rate (output). Alternatively, the inverter 240 can be used to operate the compressor in a capacity control mode, in which the motor rotation speed is controlled according to the amount of compressed gas used, thereby adjusting the discharge flow rate (output). Alternatively, the inverter 240 can be used in a fixed control mode, in which the discharge flow rate (output) is maintained constant regardless of the amount of compressed gas used. For example, in a unit count control mode, when there is little fluctuation in the amount of gas used, the compressor unit 100 may be stopped and started, but the rotation speed of the motor 120 may be controlled to constantly maintain the discharge pressure (tank pressure) near the lower limit pressure. This avoids operation in a high-pressure range, thereby reducing power consumption.

[0107] The control device 280 determines whether the following first to fifth stop conditions are met. If any of the first to fifth stop conditions is met, the control device 280 sets a stop flag and stops the compression module 101 for which the stop flag is set. (First stop condition) The temperature difference ΔT, which is the difference between the temperature T1 of the compressor main body 110 and the ambient temperature T2 of the compressor 20, is equal to or greater than the temperature threshold T0. In other words, a temperature abnormality has occurred. (Second stop condition) The current I detected by the current sensor 236 is equal to or greater than the current threshold value I0. In other words, a current abnormality has occurred. (Third stop condition) The cumulative operating time has reached the maintenance time. (Fourth Stop Condition) The voltage V detected by the voltage sensor 235 is equal to or higher than the high voltage threshold VH. In other words, a high voltage abnormality has occurred. (Fifth Stop Condition) The voltage V detected by the voltage sensor 235 is lower than the low voltage threshold VL. That is, a low voltage abnormality has occurred.

[0108] The first and third stop conditions of the second embodiment are similar to the first and third stop conditions of the first embodiment, and therefore a description thereof will be omitted. The second stop condition of the second embodiment is the same in that the occurrence of a current abnormality is set as a stop condition, but in the second embodiment, an overcurrent is detected based on the current I detected by the current sensor 236 of the inverter 240. The causes of temperature abnormalities and current abnormalities are similar to those of the first embodiment, and therefore a description thereof will be omitted.

[0109] The process by the control device 280 to determine whether the fourth stop condition is satisfied is synonymous with the process to determine whether a high-voltage abnormality exists. When the check valve 151 of a specific compression module 101 deteriorates over time, compressed gas may flow back into the compressor body 110 of the specific compression module 101 from the main discharge pipe 105 side. When compressed gas flows back into the compressor body 110 of the specific compression module 101 while the specific compression module 101 is stopped, the compressor body 110 rotates, and the motor 120 rotates. As a result, the motor 120 generates electricity, and the voltage V detected by the voltage sensor 235 increases above normal. In other words, when the check valve 151 deteriorates and backflow into the compressor body 110 occurs, the control device 280 detects a high-voltage abnormality.

[0110] The process by the control device 280 to determine whether the fifth stop condition is met is synonymous with the process to determine whether a low voltage abnormality exists. If the check valve 151 of a certain compression module 101 deteriorates over time and causes a leak of compressed gas, a step-out may occur when the compressor unit 100 is driven. As a result, the voltage V detected by the voltage sensor 235 becomes lower than normal. In other words, if the check valve 151 deteriorates and the compressor unit 100 loses step-out, the control device 280 detects a low voltage abnormality.

[0111] When a first stop condition is met, the control device 280 sets the temperature abnormality stop flag Ft(j) as the stop flag (Ft(j)=1). When a second stop condition is met, the control device 280 sets the current abnormality stop flag Fi(j) as the stop flag (Fi(j)=1). When a third stop condition is met, the control device 280 sets the maintenance stop flag Fm(j) as the stop flag (Fm(j)=1). When a fourth stop condition is met, the control device 280 sets the high voltage abnormality stop flag Fvh(j) as the stop flag (vh(j)=1). When a fifth stop condition is met, the control device 280 sets the low voltage abnormality stop flag Fvl(j) as the stop flag (Fvl(j)=1).

[0112] The control device 280 determines whether the current I(j) detected by the current sensor 236 is equal to or greater than the current threshold I0. The current threshold I0 is stored in advance in the non-volatile memory 182. If the current I(j) is less than the current threshold I0, the control device 280 determines that the second stop condition is not met and keeps the current abnormality stop flag Fi(j) in an unset state (Fi(j)=0). If the current I(j) is equal to or greater than the current threshold I0, the control device 280 determines that the second stop condition is met and sets the current abnormality stop flag Fi(j) (Fi(j)=1). The current abnormality stop flag Fi(j) is a stop flag indicating that a current abnormality has been detected in the compressor unit 100 of the compression module 101, and is set in association with the compression module 101 for which it has been determined that the second stop condition is met.

[0113] The control device 280 determines whether the voltage V(j) detected by the voltage sensor 235 is equal to or greater than the high-voltage threshold VH. The high-voltage threshold VH is stored in advance in the non-volatile memory 182. If the voltage V(j) is less than the high-voltage threshold VH, the control device 280 determines that the fourth stop condition is not met and keeps the high-voltage abnormality stop flag Fvh(j) in an unset state (Fvh(j) = 0). If the voltage V(j) is equal to or greater than the high-voltage threshold VH, the control device 280 determines that the fourth stop condition is met and sets the high-voltage abnormality stop flag Fvh(j) (Fvh(j) = 1). The high-voltage abnormality stop flag Fvh(j) is a stop flag indicating that a high-voltage abnormality has been detected in the compressor unit 100 of the compression module 101, and is set in association with the compression module 101 for which it has been determined that the fourth stop condition is met.

[0114] The control device 280 determines whether the voltage V(j) detected by the voltage sensor 235 is less than a low-voltage threshold VL. The low-voltage threshold VL is a threshold lower than the high-voltage threshold VH and is stored in advance in the non-volatile memory 182. If the voltage V(j) is equal to or greater than the low-voltage threshold VL, the control device 280 determines that the fifth stop condition is not met and keeps the low-voltage abnormality stop flag Fvl(j) in an unset state (Fvl(j) = 0). If the voltage V(j) is less than the low-voltage threshold VL, the control device 280 determines that the fourth stop condition is met and sets the low-voltage abnormality stop flag Fvl(j) (Fvl(j) = 1). The low-voltage abnormality stop flag Fvl(j) is a stop flag indicating that a low-voltage abnormality has been detected in the compressor unit 100 of the compression module 101, and is set in association with the compression module 101 for which it has been determined that the fifth stop condition is met.

[0115] The control device 280 according to the second embodiment executes the same processing as that shown in Figures 5 and 6 described in the first embodiment. In the second embodiment, in step S105 shown in Figure 5, the control device 280 executes processing to determine whether the first to fifth stop conditions are met. If the control device 280 determines that the stop conditions are met, it sets a stop flag in association with the compression module 101 for which it has determined that the stop condition is met.

[0116] In step S135 shown in Fig. 6, the control device 280 executes a trial run process in which the compression module 101 selected in step S130 is operated for a predetermined time tp. In the second embodiment, the control device 280 rotates the motor 120 at a minimum speed Ntmin during the trial run process. The minimum speed Ntmin is the minimum value within the speed control range of the motor 120. The minimum speed Ntmin can also be considered the minimum value of the speed at which the compressor unit 100 can be stably rotated.

[0117] In this way, the control device 280 according to the second embodiment operates the motor 120 of the compressor unit 100 that is not subject to the unit count control at the minimum speed for a predetermined time and then stops the motor 120. If a current abnormality in the compressor unit 100 is detected due to contact between the wrap portions 111b and 112b and the compressor unit 100 is stopped, performing a test run at the maximum speed within the speed control range of the motor 120 may damage the wrap portions 111b and 112b. In contrast, in the second embodiment, the motor 120 is operated at the minimum speed, which prevents damage to the compression module 101. In other words, according to the second embodiment, it is possible to determine whether the motor 120 is normal through a test run while preventing damage to the compression module 101.

[0118] <Modification of the second embodiment> The control device 280 may gradually increase the rotation speed of the motor 120 of the compressor unit 100 that is not subject to the unit number control from a minimum speed Ntmin to a predetermined speed (e.g., a maximum speed Ntmax) over time. The non-volatile memory 182 stores a target rotation speed table (see FIG. 9), which is a data table that defines the relationship between the elapsed time te of the test operation and the target rotation speed Nt. As shown in FIG. 9, when the elapsed time te of the test operation is from 0 to te1, the target rotation speed Nt is the minimum speed Ntmin. After the elapsed time te of the test operation passes te1, the target rotation speed Nt increases as the elapsed time te of the test operation becomes longer. When the elapsed time te of the test operation reaches te2, the target rotation speed Nt becomes the maximum speed Ntmax. After the elapsed time te of the test operation passes te2, the target rotation speed Nt is maintained at the maximum speed Ntmax. When the elapsed time te of the test operation passes te2, the target rotation speed Nt is maintained at the maximum speed Ntmax. When the elapsed time te of the test operation reaches a predetermined time tp, the target rotation speed Nt becomes 0.

[0119] When the control device 280 starts the test run process (step S135 in FIG. 6), it starts measuring the elapsed time te of the test run. The control device 280 calculates the target rotation speed Nt according to the elapsed time te by referring to the target rotation speed table shown in FIG. 9. The control device 280 outputs a control signal to the inverter 240 to rotate the motor 120 at the target rotation speed Nt.

[0120] As a result, the rotation speed of the motor 120 gradually increases over time. According to this modification, it is possible to check for the presence or absence of a specific abnormality depending on the rotation speed.

[0121] For example, if the tip seals 111d, 112d are deteriorated, high-temperature compressed gas leaks through the tip seals 111d, 112d and is further compressed, even when the rotation speed of the motor 120 is low, causing the temperature of the compressor body 110 to rise. Note that when a test run is performed at low speed, the rotation speed of the cooling fan 130 is also low, so the temperature of the compressor body 110 is likely to rise. Therefore, by measuring the temperature of the compressor body 110, the user can check whether the tip seals 111d, 112d have deteriorated while the test run is being performed at low speed.

[0122] Furthermore, as the rotation speed of the motor 120 increases, the amount of deformation of the wrap portions 111b and 112b increases due to centrifugal force. Therefore, the user can check whether the wrap portions 111b and 112b are in contact with each other by listening to the sound generated by the compressor unit 100 or measuring the motor drive current while the rotation speed of the motor 120 gradually increases.

[0123] In this way, in this modified example, it is possible to check whether or not there is a specific abnormality depending on the rotation speed, so that the cause of the abnormality can be easily identified.

[0124] <Third embodiment> A compressor 30 according to a third embodiment of the present invention will be described with reference to Fig. 10 and Fig. 11. Components that are the same as or equivalent to those described in the second embodiment are given the same reference numerals, and differences will be mainly described. Fig. 10 is a diagram similar to Fig. 8, and shows the configuration of a compressor 30 according to the third embodiment of the present invention.

[0125] 10, the compressor 30 includes a microphone 337 as a sound acquisition device that acquires sound generated from the compressor unit 100. The microphone 337 is provided for each compression module 101, converts the acquired sound into an electrical signal (hereinafter referred to as sound data), and outputs the electrical signal to the control device 380 via a signal line (not shown). The control device 380 determines whether or not there is an abnormality in the compressor unit 100 for which the test run process has been executed, based on the sound generated from the compressor unit 100 for which the test run process has been executed, and outputs the determination result.

[0126] Fig. 11 is a flowchart similar to Fig. 6, showing the details of control when the test operation mode is set by the control device 380 according to the third embodiment. In the flowchart of Fig. 11, steps S335, S336, and S337 are executed instead of step S135 in the flowchart of Fig. 6.

[0127] 11 , in the control device 380 according to the third embodiment, when the compression module 101 to be test run is selected in step S130, the process proceeds to step S335. In step S335, the control device 380 executes a test run process in which the motor 120 of the compression module 101 selected in step S130 is operated for a predetermined time tp. Furthermore, during the test run process, the control device 380 acquires sound data from the microphone 337 and stores the sound data in the nonvolatile memory 182.

[0128] When the test run process (step S335) is completed, the process proceeds to step S336. In step S336, the control device 380 diagnoses whether or not there is an abnormality in the compressor unit 100 for which the test run process was executed. In this automatic diagnosis process (step S336), the control device 380 compares the sound data acquired in step S335 and stored in the nonvolatile memory 182 with reference sound data previously stored in the nonvolatile memory 182. The reference sound data is, for example, sound data measured at the time of shipping the compressor 30. The control device 380 determines whether or not there is an abnormality in the compressor unit 100 based on the comparison result between the acquired sound data and the reference sound data. For example, if the difference between the frequency of the acquired sound data and the frequency of the reference sound data is within a predetermined tolerance range, the control device 380 determines that there is no abnormality in the compressor unit 100. If the difference between the frequency of the acquired sound data and the frequency of the reference sound data is outside the predetermined tolerance range, the control device 380 determines that there is an abnormality in the compressor unit 100. The control device 380 may determine that there is no abnormality in the compressor unit 100 if the difference (amplitude difference) between the maximum value of the amplitude (volume) of the acquired sound data and the maximum value of the amplitude (volume) of the reference sound data is within a predetermined allowable range, and may determine that there is an abnormality in the compressor unit 100 if the amplitude difference is outside the predetermined allowable range.

[0129] When the automatic diagnosis process (step S336) is completed, the process proceeds to step S337. In step S337, the control device 380 causes the display unit 171a to display the determination result (diagnosis result) in step S337, and the process proceeds to step S140. Note that the output process of the diagnosis result (step S337) can also be a process of outputting the diagnosis result by a sound output device such as a speaker, instead of a process of outputting the diagnosis result by the display unit 171a.

[0130] According to the third embodiment, when the test run process is performed, it is possible to automatically diagnose whether or not there is an abnormality in the compressor unit 100. Therefore, the user can easily determine whether or not to cancel the stop flag.

[0131] <Modification of the third embodiment> In the third embodiment, an example has been described in which it is determined whether or not there is an abnormality in the compressor unit 100 for which the test run process has been executed, based on the sound generated from the compressor unit 100 for which the test run process has been executed and acquired by the microphone 337. However, the present invention is not limited to this. The control device 380 may determine whether or not there is an abnormality in the compressor unit 100 for which the test run process has been executed, based on the current supplied to the motor 120 of the compressor unit 100 for which the test run process has been executed, i.e., the current detected by the current sensor 236. The control device 380 may also determine whether or not there is an abnormality in the compressor unit 100 for which the test run process has been executed, based on the temperature of the compressor body 110 of the compressor unit 100 for which the test run process has been executed, i.e., the temperature detected by the temperature sensor 132.

[0132] That is, the control device 380 may be configured to determine whether or not there is an abnormality in the compressor unit 100 for which the test run process has been executed, based on at least one of the sound generated by the compressor unit 100 for which the test run process has been executed, the current supplied to the motor 120, and the temperature of the compressor main body 110, and to output the determination result. With this configuration, it is possible to automatically diagnose whether or not there is an abnormality in the compressor unit 100 when the test run process is executed. This allows the user to easily determine whether or not to cancel the stop flag.

[0133] Note that, when an automatic diagnosis of the compressor unit 100 for which the test run process has been executed determines that there is no abnormality in the compressor unit 100, the control device 380 may automatically reset the stop flag. In this case, since the user does not need to reset the stop flag, the time from the test run to the return to the number control can be shortened.

[0134] The following modified examples are also within the scope of the present invention, and it is possible to combine the configuration shown in the modified example with the configuration described in the above embodiment, to combine the configurations described in the different embodiments above, or to combine the configurations described in the different modified examples below.

[0135] <Variation 1> The first and fifth stop conditions may be satisfied due to erroneous detection of temperature abnormalities and low voltage abnormalities. A false detection of a temperature abnormality may occur, for example, when the temperature difference ΔT exceeds the temperature threshold value T0 due to the opening and closing of a door in a room where the compressors 10, 20, and 30 are installed, the operation of an air conditioner, or the like. A false detection of a low voltage abnormality may occur, for example, when control involving a large speed change is performed on the motor 120, and the rotor 122 is unable to properly follow the rotating magnetic field generated by the current supplied from the inverter 240 to the stator 121, causing a loss of synchronism, causing the motor drive voltage V to fall below the low voltage threshold value VL. In contrast, the second, third, and fourth stop conditions are not satisfied due to erroneous detection. For this reason, the control devices 180, 280, and 380 may determine whether to perform the trial run process based on the stop flag.

[0136] When any of a plurality of predetermined stop conditions is met, the control devices 180, 280, and 380 according to this modified example set a stop flag according to the met stop condition, and determine whether or not to execute the trial run process based on the set stop flag.

[0137] An example of a modification of the second embodiment will be described below. As shown in Fig. 12, the nonvolatile memory 182 of the control device 280 stores the relationship between a stop flag and whether or not the test run process can be executed. As shown in Fig. 12, when the temperature abnormality stop flag or the low voltage abnormality flag is set, the control device 280 determines that the test run process can be executed and displays this on the display unit 171a. When the temperature abnormality stop flag or the low voltage abnormality flag is set and an operation to start the test run is performed on the operation panel 170, the control device 280 sets the test run mode and executes the process shown in the flowchart of Fig. 6.

[0138] On the other hand, if the high-voltage abnormality stop flag is set, the control device 280 determines that the test run process cannot be executed and displays that fact on the display unit 171a. For example, the control device 280 displays a message such as "A high-voltage abnormality has occurred. Please replace the check valve 151," or an error code corresponding to that message on the display unit 171a. If an operation to start a test run is performed on the operation panel 170 while the high-voltage abnormality stop flag is set, the control device 280 displays on the display unit 171a that the test run process cannot be executed and does not set the test run mode.

[0139] This prevents a test run from being performed on the compression module 101 in which a high-voltage abnormality has been detected before the check valve 151 has been replaced. The user stops the entire compressor 20, including the compression module 101 in which no abnormality has been detected, replaces the check valve 151 of the compression module 101 in which an abnormality has been detected, and then performs a reset operation on the operation panel 170. This causes the control device 280 to clear the high-voltage abnormality stop flag for the compression module 101. Note that the control device 280 also clears the high-voltage abnormality stop flag when the power to the compressor 10 is turned off.

[0140] Similarly, when the current abnormality stop flag is set, the control device 280 determines that the test run process cannot be executed and displays that fact on the display unit 171a. For example, the control device 280 displays a message such as "A current abnormality has occurred. Repair or replace the compressor unit," or an error code corresponding to that message, on the display unit 171a. When the current abnormality stop flag is set and an operation to start a test run is performed on the operation panel 170, the control device 280 displays on the display unit 171a that the test run process cannot be executed and does not set the test run mode.

[0141] This prevents a test run from being performed on a compression module 101 in which a current abnormality has been detected before the compressor unit 100 has been repaired or replaced. The user stops the entire compressor 20, including the compression module 101 in which no abnormality has been detected, repairs or replaces the compressor unit 100 of the compression module 101 in which an abnormality has been detected, and then performs a reset operation on the operation panel 170. This causes the control device 280 to clear the current abnormality stop flag for the compression module 101. Note that the control device 280 also clears the current abnormality stop flag when the power to the compressor 10 is turned off.

[0142] As described above, according to this modification, the control device 280 determines whether to perform a test run depending on the type of the stop flag. Therefore, if a predetermined stop flag (for example, a high voltage abnormality stop flag or a current abnormality flag) is set, the test run is prohibited, thereby preventing damage to the compression module 101 due to the test run.

[0143] <Variation 2> In step S135 of Fig. 6, the control devices 180, 280 rotate the motor 120 of the compression module 101 for a predetermined time tp and then automatically stop the motor 120, but the present invention is not limited to this. The control device 180 may end the trial run process (step S135 of Fig. 6) in response to an operation by the user.

[0144] For example, in step S135 of Fig. 6, if the stop switch 172b on the operation panel 170 is operated while the motor 120 of the compression module 101 is rotating, the control device 180 stops the motor 120 before the predetermined time tp has elapsed. With this configuration, a test run can be performed that is suited to the state of the compressor unit 100.

[0145] <Variation 3> In the above embodiment, a configuration has been described in which the shaft 123 of the motor 120 is directly attached to the orbiting scroll 112 and the power of the motor 120 is directly transmitted to the orbiting scroll 112. However, the present invention is not limited to this. Pulleys may be provided on the shaft of the motor 120 and the shaft of the orbiting scroll 112, and a belt that transmits the power generated by the motor 120 to the orbiting scroll 112 may be attached to the pulleys of the motor 120 and the orbiting scroll 112. In this configuration, if the belt wears or stretches due to deterioration over time, the force required to drive the compressor body 110 increases, causing the motor drive current to rise above normal. In other words, if the belt deteriorates, the control device 180 will detect a current abnormality.

[0146] <Variation 4> The stop conditions are not limited to those described in the above embodiment. For example, in the second embodiment, when an abnormality is detected in the inverter 240, the control device 280 may set a stop flag, assuming that the stop conditions are met.

[0147] <Variation 5> In the first embodiment, the control device 180 detects abnormalities caused by deterioration over time of the tip seals 111d, 112d, the bearings 124A, 124B, and the wrap portions 111b, 112b. However, the present invention is not limited to this. For example, the magnets used in the motor 120 gradually demagnetize due to deterioration over time. Therefore, the control device 180 may be configured to detect current abnormalities caused by deterioration over time of the magnets.

[0148] <Variation 6> In the above embodiment, an example has been described in which the compressors 10, 20, and 30 include the scroll compressor unit 100, but the present invention is not limited to this. The compressors 10, 20, and 30 may include a plurality of well-known screw, reciprocating (piston), and turbo compressor units. The present invention may also be applied to a compressor including a plurality of compressor units of different models. For example, the present invention may be applied to a compressor including a control device that controls the number of operating compressor units, a total of four compressor units, including two scroll compressor units and two reciprocating compressor units.

[0149] The above-described embodiments are merely illustrative examples for aiding in understanding the concept of the present invention, and are not intended to limit the scope of the present invention. Various components may be added, deleted, or converted to the embodiments without departing from the spirit of the present invention.

[0150] The various functional units described in the above embodiments may be realized using circuits, which may be dedicated circuits for realizing specific functions or general-purpose circuits such as processors.

[0151] At least a part of the processing of each of the above embodiments can be realized by using a general-purpose computer as basic hardware. A program for realizing the above processing may be provided by being stored on a computer-readable recording medium. The program is stored on the recording medium as an installable file or an executable file. Examples of recording media include magnetic disks, optical disks (CD-ROMs, CD-Rs, DVDs, etc.), magneto-optical disks (MOs, etc.), and semiconductor memories. Any recording medium can be used as long as it can store the program and is computer-readable. Furthermore, the program for realizing the above processing may be stored on a computer (server) connected to a network such as the Internet and downloaded to a computer (client) via the network. [Explanation of symbols]

[0152] 10, 20, 30... compressor, 100... compressor unit, 101... compression module, 105... main discharge piping (piping), 110... compressor body, 111b, 112b... lap portion, 111d, 112d... tip seal (sealing member), 120... motor, 124A, 124B... bearing, 131... pressure sensor, 132... temperature sensor, 133... ambient temperature sensor, 140... electromagnetic switch, 151... check valve, 170... operation panel, 171a, 171b... display unit, 1 72a... operation switch (operation switch), 172b... stop switch (operation switch), 172c... menu switch (operation switch), 172d... display changeover switch (operation switch), 180... control device, 181... processor, 182... non-volatile memory, 183... volatile memory, 190... communication device, 235... voltage sensor, 236... current sensor, 240... inverter, 280... control device, 337... microphone (sound acquisition device), 380... control device

Claims

1. The system comprises multiple compressor units, each having a compressor body for compressing a gas and a motor for driving the compressor body. Piping for connecting multiple compressor units, A control device for controlling multiple compressor units, An operation panel or external information terminal for inputting commands to the control device, A compressor comprising a housing that houses a plurality of the compressor units, the control device, and the piping, and has the operation panel on its surface, The control device is Of the multiple compressor units, the compressor unit that has met the abnormal stop conditions is stopped from operating. While continuing the number-control operation of the other compressor units, a test run is performed on the compressor unit that has met the abnormal stop conditions, and after the test run is completed, the stopped compressor unit is restarted and the number-control operation is resumed. The aforementioned trial run is an operation that limits the operating time or rotational speed. The process of restarting the compressor unit, which has been stopped after the aforementioned trial run, is performed by the control device after a command indicating that there is no abnormality has been input from the operation panel or the external information terminal.

2. The system comprises multiple compressor units, each having a compressor body for compressing a gas and a motor for driving the compressor body. Piping for connecting multiple compressor units, A control device for controlling multiple compressor units, An operation panel or external information terminal for inputting commands to the control device, A compressor comprising a housing that houses a plurality of the compressor units, the control device, and the piping, and has the operation panel on its surface, The control device is Of the multiple compressor units, the compressor unit that has met the abnormal stop conditions is stopped from operating. While continuing the number-control operation of the other compressor units, a test run is performed on the compressor unit that has met the abnormal stop conditions, and after the test run is completed, the stopped compressor unit is restarted and the number-control operation is resumed. The aforementioned trial run involves gradually increasing the rotational speed. The process of restarting the compressor unit, which has been stopped after the aforementioned trial run, is performed by the control device after a command indicating that there is no abnormality has been input from the operation panel or the external information terminal.

3. In the compressor according to Claim 1, The aforementioned trial run is a compressor operation that limits both the operating time and the rotational speed.

4. In the compressor according to Claim 1, The aforementioned trial run is a compressor operation in which the operating time is limited and the rotational speed is gradually increased.

5. In the compressor according to claim 1 or claim 2, The aforementioned trial run is initiated after the control device receives a command from the operation panel or the external information terminal.

6. In the compressor according to claim 1 or claim 2, The control device is A compressor in which, if the aforementioned trial run has not been completed, the compressor unit that has met the aforementioned abnormal stop conditions cannot be returned to the aforementioned unit control operation.

7. In the compressor according to claim 1 or claim 2, The control device is A compressor that determines whether or not the aforementioned abnormal shutdown conditions have been met based on one of the following: current, voltage, temperature, or cumulative operating time.

8. In the compressor according to claim 1 or claim 2, The control device is A compressor in which, if there are two or more compressor units that satisfy the aforementioned abnormal stop conditions, the aforementioned test run is performed on each unit individually.

9. In the compressor according to claim 1 or claim 4, The control device is a compressor that sets the operating time for the trial run based on trial run time information input from the operation panel or the external information terminal.

10. In the compressor according to claim 8, The control device determines which compressor unit will perform a trial run based on a selection command input from the operation panel or the external information terminal.

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