JP4463011B2 - Capacity control method and capacity control apparatus for fluid compressor - Google Patents

Description

  The present invention relates to a capacity control method and a capacity control apparatus for a fluid compressor, and as an example, relates to a capacity control method and a capacity control apparatus suitable for capacity control of a fluid compressor that compresses a fuel gas such as city gas.

  A fluid compressor that compresses air, fuel gas, and other various fluids, mainly gas, and obtains a compressed fluid compressed to a predetermined pressure is used in various applications.

  As such a fluid compressor 1, two screw rotors are engaged with each other in a cylinder so as to be rotatable, and lubricating oil is supplied into the cylinder to seal and cool between the screw rotors and between the screw rotors and the cylinders. The fluid compressor 1 including the oil-cooled screw compressor main body 10 that can be lubricated will be described as an example. The fluid compressor 1 includes the oil-cooled screw compressor main body 10 and the compression compressor. A drive source such as an engine and an electric motor 15 for driving the machine main body 10, a compressed fluid discharged together with the lubricating oil from the compressor main body 10, and a receiver tank 12 for separating the compressed fluid and the lubricating oil are provided. A suction control valve 33 for opening or closing the suction port 10a of the compressor body 10 is provided.

  Then, when the screw rotor disposed in the cylinder of the compressor body 10 is rotated, the fluid to be compressed sucked from the suction port 10a together with the lubricating oil used for cooling, sealing, lubrication, etc. Are discharged from the discharge port 10b and introduced into the receiver tank 12 through a discharge passage 61 communicated with the discharge port 10b of the compressor body 10.

  The compressed fluid introduced into the receiver tank 12 together with the lubricating oil is separated from the lubricating oil in the receiver tank 12 by, for example, a separator 14 or the like, and the compressed fluid from which the lubricating oil has been removed is supplied to the compressed fluid via the supply passage 63. To the consumer side to which the consumer device 16 is connected.

  On the other hand, the lubricating oil recovered in the receiver tank 12 is introduced into the oil supply port 10c of the compressor main body 10 through the oil supply passage 62 due to the pressure in the receiver tank 12, and is again screwed in the cylinder in the compressor main body 10. It is used for sealing, cooling, and lubrication between the rotor and between the screw rotor and the cylinder, and is discharged and collected in the receiver tank 12 together with the compressed fluid, and circulates between the receiver tank 12 and the compressor body 10.

  The oil supply passage 62 is provided with an oil cooler (not shown) to cool the lubricating oil introduced into the compressor body 10.

  In such a fluid compressor 1, the compressor main body 10 is controlled by controlling the intake control valve 33 according to the consumption amount of the compressed fluid by the consuming device 16 connected to the consumption side of the fluid compressor 1. Capacity control for performing suction control for adjusting the suction amount of the fluid to be compressed introduced into the compressor and speed control for controlling the operating speed of the compressor body by controlling the rotational speed of the drive source for driving the compressor body. It is configured so that an efficient operation can be performed according to the consumption amount of the compressed fluid.

As an example of such capacity control (speed control), an electric motor is used as a drive source for the compressor body, and the operation speed control of the compressor body by the motor is controlled by an inverter. A pressure sensor is provided in the supply passage 63) in FIG. 4 to detect fluctuations in the amount of air used (consumption) based on pressure, perform constant pressure control using a PI controller, and control the capacity by controlling the number of revolutions of the motor using an inverter. (Speed control) (see Patent Document 1),
A pressure sensor for detecting the pressure of the compressed air discharged from the screw compressor and a PID control circuit for determining the output rotation speed to the inverter so that the change in the detected pressure of the pressure sensor with respect to the set value is minimized Even if the amount of air used (consumption) changes, it is possible to always supply compressed air at a constant pressure, and to start the screw compressor with its suction side closed by the rotation signal from the inverter, There is an oil-cooled screw compressor in which the starting torque of the screw compressor does not exceed the starting torque of the inverter (see Patent Document 2).

Prior art document information of the present invention includes the following.
Japanese Patent Laid-Open No. 6-10876 Japanese Unexamined Patent Publication No. 6-81782

  As described above, in the fluid compressor 1 including the oil-cooled screw compressor main body 10, the compressor main body 10 injects lubricating oil into the cylinder as described above to compress the fluid to be compressed. However, before the compressor body 10 is started, there is no pressure difference between the cylinder of the compressor body 10 and the receiver tank 12.

  Therefore, in the fluid compressor 1 configured to supply the lubricating oil stored in the receiver tank 12 into the cylinder of the compressor body 10 by the pressure in the receiver tank 12 as described above, the pressure in the receiver tank 12 is Immediately after the start-up in which the pressure is not sufficiently increased, the rotors are lubricated only with the lubricating oil accumulated in the cylinder. Therefore, the temperature of the compressor main body 10 is likely to rise due to frictional heat between the rotors and compression heat of the fluid to be compressed.

  In addition, as described above, the pressure of the compressed air discharged from the screw compressor is detected, and the output rotation speed to the inverter is calculated so that the change in the detected pressure with respect to the set value is minimized, and the rotation of the screw compressor is calculated. In the screw compressors described in Patent Document 1 and Patent Document 2 that control the number, the pressure of the compressed air discharged from the compressor main body at the start-up of the compressor main body is extremely low compared to the set value. Because of the pressure, the inverter output frequency calculated by the above-described PI control device and PID control circuit becomes the maximum number of revolutions, and the motor 15 rapidly rotates at a high speed. As a result, the compressor main body 10 driven thereby Also, it will be driven at a higher speed than immediately after startup. Therefore, the temperature rise of the compressor body as described above occurs in a very short time.

  In particular, when such a fluid compressor 1 is used at a low temperature such as in a cold region, the lubricating oil that is cooled by the surrounding air temperature and has a high viscosity and a low fluidity is used in the receiver tank. 12, it is difficult to supply oil into the cylinder of the compressor main body 10, and the compressor main body 10 is operated at high speed in a non-oiled state for a relatively long time after startup.

  As a result, the temperature of the compressor body 10 rises abnormally due to such high-speed operation in the oil-free state, the screw rotors are seized and damaged, or the emergency stop device provided in the fluid compressor 1 is There is a problem that the operation is stopped by detecting the temperature rise and the operation is stopped, so that the fluid compressor cannot be operated.

  In addition, when using a so-called “oil-free screw compressor main body” that does not require the introduction of lubricating oil into the cylinder as the compressor main body 10, in the oil-free screw compressor main body, Since the fluid to be compressed is originally compressed without injecting lubricating oil into the cylinder, no oil is supplied into the cylinder of the compressor body at the time of start-up, unlike the oil-cooled screw compressor body described above. The problem cannot occur.

  However, in the case of such an oil-free compressor body, the screw rotors are not in contact with each other, and the compressed fluid is compressed without lubricating the rotors or between the cylinders and the rotors with lubricating oil. Therefore, it is necessary to rotate the rotor at a higher speed than an oil-cooled compressor (as an example, oil-free about 20,000 min-1 versus oil-cooled about 5,000 min-1).

  Therefore, compared to the oil-cooled screw compressor body described above, the oil-free screw compressor body has a higher temperature of the compressed fluid to be discharged (for example, oil-cooled is MAX105 ° C and oil-free is MAX250 In addition, since it is necessary to rotate the rotor at a high speed as compared with the oil-cooled screw compressor body as described above, Patent Document 1 and Patent for such an oil-free screw compressor When the capacity control (speed control) shown in Document 2 is performed, the rotational speed increases immediately after startup more rapidly than the oil-cooled screw compressor body, and this causes a rapid temperature increase. Therefore, there is a problem that a large burden is applied to the bearing and the shaft seal device.

  In the case of compressing city gas, for example, with a fluid compressor that has been subjected to volume control as described above, a suction gas meter (so-called so-called gas meter) installed by a gas supplier is provided at the inlet of the compressor body. It will be communicated to the city gas supply source via the “microcomputer meter”).

  By the way, the gas meter (microcomputer meter) installed for billing in this way not only measures the gas flow rate for billing in recent years but also detects earthquakes and gas leaks (abnormal pressure drop). However, if the compressor body starts high-speed operation immediately after startup and suddenly draws in city gas as described above, the pressure on the downstream side of the microcomputer meter is reduced. Since it suddenly and drastically decreases, the microcomputer meter causes a malfunction in which the rapid decrease in pressure is judged as a gas leak and the supply of city gas is stopped.

  In addition, if the pressure in the gas flow passage provided in the microcomputer meter is lower than the atmospheric pressure, the microcomputer meter may be damaged. Therefore, a fluid compressor that causes a sudden and significant pressure drop as described above is provided. There is a problem that it cannot be connected to the aforementioned gas meter (microcomputer meter).

  In the capacity control method described in the above-mentioned Patent Document 2, when the compressor body is started, the suction port of the compressor body is closed and no load is applied. Even if it is arranged downstream, the pressure on the downstream side of the microcomputer meter does not drop immediately after the compressor body is started.

  However, the start in the no-load operation performed in this way is performed in order to reduce the starting torque of the compressor body, and after the start, the rotation speed of the compressor body gradually increases and the normal load When passing the peak value at the time of starting and reaching a low starting torque speed, the suction side of the compressor body is opened by the suction side opening / closing means controlled by the rotational speed signal from the inverter, and the compressor body is loaded. Since the operation is started ("0011" column of Patent Document 1), the pressure on the suction side of the compressor body, that is, the pressure on the downstream side of the microcomputer meter is suddenly reduced simultaneously with the start of the load operation. There is a risk of malfunction or damage of the microcomputer meter.

  Accordingly, the present invention has been made to eliminate the above-described drawbacks of the prior art, and the temperature of the compressor main body (for example, the rotor or cylinder) when the compressor main body is started, that is, when the electric motor that drives the compressor is started. Temperature and the temperature of the compressed fluid) is prevented from abruptly rising, preventing damage to the compressor body, and without causing a stop due to the operation of the emergency stop device accompanying the temperature rise of the compressed fluid. It is an object of the present invention to provide a capacity control method and capacity control apparatus for a fluid compressor that can be started.

  Another object of the present invention is to provide a fluid compressor capacity control method and capacity control device capable of preventing a sudden drop in the pressure on the suction side of the compressor body at the time of startup. It is an object of the present invention to prevent malfunctions or damage of devices such as the microcomputer meter attached to the suction side of a compressor main body provided in the machine.

In order to achieve the above object, the capacity control method and capacity control apparatus for a fluid compressor according to the present invention includes a discharge-side pressure Pd of the compressor body 10 detected by the pressure detection means 50 and a preset target pressure Pf. For example, an inverter 31 that changes the frequency input to the electric motor 15 that drives the compressor body 10 so that the discharge side pressure Pd matches the target pressure Pf, and a PI operation circuit of the inverter 31 or A command signal comprising a signal indicating the detected discharge side pressure Pd (hereinafter referred to as “pressure signal”) and a signal indicating the target pressure (hereinafter referred to as “target pressure signal”) to the PID arithmetic circuit. a speed control by the speed control means and an output signal output means 40, etc., are preset discharge pressure Pd of the compressor body 10 detected by the pressure detecting means 50 When the detected discharge side pressure Pd of the compressor main body 10 is lower than the reference pressure Pv compared to the reference pressure Pv, the suction port 10a of the compressor main body 10 is opened and the discharge side of the compressor main body 10 is discharged. Including suction control by suction control means (suction control valve 33, electromagnetic valve 34, control pipe 35, electronic control device, etc.) that closes the suction port 10a of the compressor body 10 when the pressure Pd exceeds the reference pressure Pv. ,
In the storage means provided in the speed control means (in the embodiment, the storage unit 43 of the signal generation means 40), as the target pressure Pf, the steady-state target pressure Pf2 is relatively low with respect to the steady-state target pressure Pf2. The set startup target pressure Pf1 is stored in advance,
For example, until the elapse of a preset time t1 from the start of the electric motor 15 is counted by the timer 44, for example, the start-time target pressure Pf1 stored in the storage means 43 is applied as the target pressure Pf. After the elapse of the set time t1, the switching is realized by switching means realized by, for example, an electronic control unit so that the steady-state target pressure Pf2 is applied as the target pressure Pf .
For example, in the storage control unit (in the embodiment, the storage unit 47 of the electromagnetic valve control unit 45 realized by the electronic control unit) provided in the electronic control unit or the like of the suction control unit, the reference pressure Pv in the steady state is used. Pv2 and the starting reference pressure Pv1 set relatively low with respect to the steady-state reference pressure Pv2 are stored in advance,
For example, by the switching means realized in the electromagnetic valve control means 45, the starting reference pressure Pv1 is applied as the reference pressure Pv from the start of the electric motor 15 until the preset set time t2, and the setting is performed. After the elapse of time t2, the steady-state reference pressure Pv2 is applied as the reference pressure Pv (claims 1 and 4 ).

Further, in the same configuration, instead of switching between the starting target pressure Pf1 and the steady-state target pressure Pf2 by the switching means, from the start of the electric motor 15 until the elapse of a preset set time t1, Regardless of the discharge side pressure Pd of the compressor body 10, the motor 15 generates a constant rotation speed (for example, an unload rotation speed N1) set relatively low compared to the rated rotation speed of the motor 15. And a frequency for making the discharge-side pressure Pd coincide with the target pressure Pf (steady-state target pressure Pf2) after the set time t1 has elapsed. 2, Claim 5 ).

Alternatively, the switching means controls the rotation of the motor by changing the frequency at a change rate that is relatively slow with respect to the change rate at the normal time from the start of the motor 15 at the set time t1. You may comprise (Claim 3, Claim 6 ).

  With the configuration of the present invention described above, the control of the operation speed of the compressor main body is targeted for the starting target pressure set relatively low with respect to the steady-state target pressure from the start of the motor to the lapse of the set time t1. By performing as a pressure, it is possible to prevent heat generation due to a sudden high speed operation of the compressor body at start-up, a sudden rise in temperature of the compressed fluid, a sudden drop in the suction side pressure of the compressor body, etc. As a result, it was possible to prevent damage to the compressor body, malfunction of safety devices, etc., malfunction or damage of equipment (for example, a gas meter) provided on the suction side of the compressor body.

  Further, instead of the above-mentioned configuration, from the start-up of the electric motor to the elapse of a preset set time, at a constant rotational speed set relatively low with respect to the rated rotational speed of the electric motor (for example, the unload rotational speed N1). Similarly, by driving the electric motor or by increasing the rotation of the electric motor by changing the frequency at the changing speed at start-up where the changing speed is relatively slow relative to the steady-state changing speed. It was possible to prevent heat generation, rapid temperature rise of the compressed fluid, rapid decrease of the suction side pressure of the compressor body, and the like due to sudden high speed operation at the start of the compressor body.

  Further, in addition to the above-described configuration, the suction control for the compressor main body is set to a low pressure compared to the steady-state reference pressure applied during steady operation from the start of the motor to the elapse of a preset set time t2. By using the starting reference pressure as a reference, the compressor main body shifts to unload operation in a relatively short time after starting.In addition to the above-described effects, the compressed fluid to the compressor main body is The introduction was stopped relatively early, and the pressure drop on the suction side of the compressor body could be prevented.

  Next, embodiments of the present invention will be described below with reference to the accompanying drawings.

  In the embodiment described below, an example in which the capacity control device of the present invention is applied to a fluid compressor that compresses fuel gas supplied via a gas meter (microcomputer meter) such as city gas will be described. However, the capacity control device of the present invention is not limited to the embodiment shown below, and can be used for capacity control of a fluid compressor used for compressing various fluids.

1. 1. Overall Configuration of Fluid Compressor (Fuel Gas Compressor) In FIG. 1, reference numeral 1 denotes a fluid compressor ("fuel gas compressor" in the present embodiment), and in the illustrated embodiment, the fuel gas compressor 1 Is composed of a compressor main body 10 that is an oil-cooled screw compressor, a receiver tank 12 that introduces fuel gas discharged from the compressor main body 10 together with lubricating oil, and a fuel gas introduced into the receiver tank 12. Refer to FIG. 4 in that it includes a separator 14 that separates and removes lubricating oil and supplies the fuel gas from which the oil has been removed to the consumption side, and an electric motor 15 that drives the compressor body 10. It is the structure similar to the fluid compressor 1 in the prior art demonstrated.

  In this embodiment, an example in which an oil-cooled screw compressor main body is used as the compressor main body 10 as described above will be described. An oil-free screw compressor body may be used. When such an oil-free screw compressor body 10 is used, the receiver tank 12 and the separator 14 described above are not necessarily required.

  The aforementioned discharge port 10b of the compressor body 10 communicates with the receiver tank 12 through a discharge passage 61, and an oil supply passage 62 is provided between the receiver tank 12 and the oil supply port 10c of the compressor body 10. The lubricating oil that is communicated and collected in the receiver tank 12 is supplied to the oil supply port 10c of the compressor body 10 by the pressure in the receiver tank 12, so that the screw rotor in the cylinder is lubricated, sealed, and cooled. The compressor body 10, the discharge passage 61, the receiver tank 12, and the oil supply passage 62 form a lubricating oil circulation system.

  The oil supply passage 62 is provided with an oil cooler (not shown) to cool the lubricating oil introduced into the compressor body 10.

  The separator 14 provided in the receiver tank 12 has a supply passage 63 for supplying the fuel gas from which oil has been removed by the separator 14 to the fuel consuming device 16 (a gas turbine in this embodiment). The fuel oil is communicated, and the lubricant is removed by the separator 14, and pressurized fuel gas is supplied to the fuel consuming device 16.

2. Capacity Control Device The fluid compressor 1 configured as described above includes a pressure sensor that detects the pressure on the discharge side of the compressor body 10 (in the present embodiment, the above-described supply passage 63). The number of rotations of the motor 15 that drives the compressor body 10 is controlled so that the discharge side pressure of the compressor body 10 detected by the pressure detection means 50 matches the preset target pressure. And a discharge side pressure of the compressor main body 10 detected by the pressure detecting means 50 is compared with a preset reference pressure, and the suction port of the compressor main body 10 based on the comparison result A capacity control device comprising suction control means for controlling the suction amount of the fluid to be compressed into the compressor body 10 by opening and closing 10a is provided, and the capacity control of the present invention is performed by this capacity control device.

2-1. Speed control means The speed control means constituting the capacity control device described above includes a pressure detection means 50 (described later) for detecting the discharge side pressure (pressure in the supply passage 63 in this embodiment) Pd of the compressor body 10; The detection signal from the pressure detection means 50 is received, the detection signal is converted into a pressure signal, the target pressure Pf is stored in advance, and a command composed of the pressure signal and the target pressure signal is sent to the inverter 31. A signal generator 40, which will be described later, outputs the signal, receives the command signal, changes the power frequency of the power input from the AC power source to a desired output frequency based on the command signal, and outputs the output frequency to the motor. The inverter 31 is configured to output electric power. By changing the frequency input to the electric motor 15 by the inverter 31, the rotational speed of the electric motor 15, and hence the operation of the compressor main body 10 can be changed. The operating speed of the compressor body is controlled by changing the rotation speed.

(1) Inverter The above-described inverter 31 is provided with a PI calculation circuit or a PID calculation circuit (not shown) that calculates the output frequency corresponding to the received pressure signal and the command signal of the target pressure signal, The inverter 31 controls the operation speed of the compressor main body by outputting the output frequency according to the calculation result by the calculation circuit to the electric motor 15.

  The output frequency calculated by the PI calculation circuit or the PID calculation circuit is the rotational speed of the electric motor 15, the pressure on the discharge side of the compressor body (the pressure in the supply passage 63 in this embodiment), The output pressure is calculated in accordance with a pressure signal received from a signal generator 40 (to be described later) and a command signal for the target pressure signal, and is changed so as to match the preset target pressure Pf. The output frequency is input to the motor 15.

  Thus, when the discharge-side pressure Pd of the compressor body 10 is equal to or lower than the target pressure Pf (Pf1, Pf2) set in advance for speed control, the inverter 31 increases the rotational speed of the motor 15 to the rated rotational speed. In this manner, the output frequency output to the motor is gradually increased to increase the operating speed of the compressor body 10, while the discharge side pressure Pd of the compressor body 10 exceeds the set target pressure Pf (Pf1, Pf2). In this case, speed control is performed to gradually decrease the output frequency output to the motor 15 so as to decrease the operation speed of the compressor body so that the rotation speed of the motor 15 is decreased to a preset unload rotation speed N1. Do. Further, when the discharge side pressure Pd of the compressor main body 10 matches the preset target pressure Pf, the output frequency is not increased or decreased so as to maintain the rotation speed of the motor 15 when the pressure matches. The same output frequency is output to the motor.

(2) Signal generating means The signal generating means 40 for outputting a command signal including the pressure signal and the target pressure signal to the inverter 31 is provided with the discharge side pressure Pd (in this embodiment) of the compressor body 10. The pressure in the supply passage 63), and a command signal comprising the above-described pressure signal corresponding to a detection signal from the pressure detection means 50 described later and a target pressure signal corresponding to a preset target pressure. Is output to the inverter 31.

  The signal generating means 40 includes a storage unit 43 that stores a preset target pressure as a pressure that serves as a reference for the operation in the speed control, and the pressure signal and the target pressure signal for the inverter 31 described above. Are provided with a command signal output unit 41 for outputting the command signal and a timer 44 for counting an elapsed time since the start of the motor 15.

  In the storage unit 43 of the signal generating means 40, the reference pressure Pf used as a reference for speed control is set as a reference from the start of the motor 15, and hence from the start of the compressor body 10 to a preset set time t1. The starting target pressure Pf1 to be stored and the steady-state target pressure Pf2 to be used as a reference after the set time t1 has elapsed since the starting of the electric motor 15 are stored.

  Further, the aforementioned set time t1 that defines the switching timing between the starting target pressure Pf1 and the steady-state target pressure Pf2 is stored.

  The startup target pressure Pf1 is set to a relatively low value with respect to the steady-state target pressure Pf2.

  The command signal output unit 41 described above converts the discharge side pressure Pd in the supply passage 63 detected by the pressure detection means 50 and the target pressure Pf into a command signal that can be used by the arithmetic circuit of the inverter 31. Output, corresponding to the target pressure signal corresponding to the startup target pressure Pf1 and the discharge side pressure Pd until the elapsed time from the startup of the motor 15 counted by the timer 44 reaches the set time t1. When the elapsed time from the start of the motor 15 counted by the timer 44 exceeds the set time t1, the target pressure signal corresponding to the steady-state target pressure Pf2 and the discharge side pressure Pd are output to the inverter 31. Switching means for outputting a pressure signal corresponding to the above to the inverter 31 is provided.

  Based on the command signal including the pressure signal and the target pressure signal, the arithmetic circuit of the inverter 31 matches the discharge side pressure Pd indicated by the received pressure signal with the target pressure Pf1 at the start within the set time t1, After the set time t2 has elapsed, an output frequency for generating the operating speed of the compressor body 10 that matches the steady-state target pressure Pf2 is calculated, and the inverter 31 calculates the output frequency obtained by this calculation to the motor 15. Output for.

2-2. Suction Control Means The suction port 10a of the compressor body 10 is provided with a suction control valve 33 for controlling the opening and closing of the suction port 10a, and the fuel gas for the compressor body 10 is controlled by controlling the opening and closing of the suction control valve 33. It is comprised so that the inhalation amount of can be controlled.

  As an example, the above suction control valve 33 that opens and closes using the discharge side pressure (pressure in the supply passage 63) of the compressor body 10 as the operating pressure is used, and the control pipe 35 branched from the supply passage 63 is controlled by the suction control. An electromagnetic valve 34 that communicates with the valve 33 and opens and closes the control pipe 35 is provided, and the control pipe 35 is opened and closed by the electromagnetic valve so that the suction port 10a of the compressor body 10 can be opened and closed.

  In the present embodiment, the suction control valve 33 is a normally open valve that is closed by introducing a compressed fluid, and the control pipe 35 is communicated with the valve-closing pressure receiving chamber of the suction control valve 33. When the control pipe 35 is opened by the electromagnetic valve 34 and the compressed fluid in the supply passage 63 is introduced, the suction port 10a of the compressor body is closed or throttled. When the control pipe 35 is closed by the electromagnetic valve 34, the compressor body 10 The suction port 10a is configured to open.

  The solenoid valve 34 is a normally open type that closes when the control signal is ON, and opens and closes the control pipe 35 by a control signal from the solenoid valve control means 45. When the discharge side pressure (pressure in the supply passage 63 in this embodiment) is equal to or lower than a preset reference pressure Pv (Pv1, Pv2), the solenoid valve is closed and the suction port of the compressor body is opened. At the same time, when this reference pressure is exceeded, the solenoid valve is opened, and the suction port of the compressor body is closed or throttled to perform suction control on the compressor body.

  Therefore, in the embodiment shown in FIG. 1, the suction control valve 33, the electromagnetic valve 34, the control pipe 35, the pressure detection means 50, and the electromagnetic valve control means 45 constitute the aforementioned suction control means.

  The electromagnetic valve control means 45 includes a storage unit 47 that stores a pressure set in advance as a reference pressure for the operation during the suction control, a control signal output unit 46 that outputs a control signal for opening and closing the electromagnetic valve 34, A timer 48 that counts the elapsed time since the start of the electric motor 15 is provided.

  In the storage unit 47 of the electromagnetic valve control means 45, a reference pressure Pv1 at the time of starting as a reference from the start of the motor 15 to a preset time t2 as a reference pressure Pv as a reference for suction control, compression The steady-state reference pressure Pv2 is stored as a reference after the set time t2 has elapsed since the start of the machine body. The storage unit stores the set time t2 that defines the switching timing between the starting reference pressure Pv1 and the steady-state reference pressure Pv2.

  The startup reference pressure Pv1 is set to a relatively low value with respect to the steady-state reference pressure Pv2.

  In the present embodiment, the target pressure Pf (Pf1, Pf2) stored in the storage unit 43 of the signal generating unit 40 and the reference pressure Pv (Pv1, Pv2) stored in the storage unit 47 of the electromagnetic valve control unit 45 are described. ) In the embodiment described with reference to the time chart shown in FIG. 2. However, in the embodiment described with reference to the time chart shown in FIG. In this example, both (Pf1 and Pv1, and Pf2 and Pv2) are set as the same value. However, the reference pressure Pv (Pv1, Pv2) is preferably set slightly higher than the target pressure Pf (Pf1, Pf2).

  The set times t1 and t2 described above will be described as separate concepts, but they may be set the same. In the time chart shown in FIG. 2, the set times t1 and t2 are the same. Set as time.

  The control signal output unit 46 compares the discharge side pressure Pd in the supply passage 63 detected by the pressure detection means 50 with the reference pressure Pv. When the discharge side pressure Pd is equal to or less than the reference pressure Pv, An ON control signal is output so as to close the solenoid valve 34. When the discharge side pressure Pd exceeds the reference pressure Pv, an OFF control signal is output so as to open the solenoid valve 34, and the motor counted by the timer 48 is output. Until the set time t2 reaches the set time t2, the start-time reference pressure Pv1 is applied as the reference pressure Pv to be compared with the discharge side pressure Pd, and the elapsed time after the start of the motor 15 is set. When the time t2 is exceeded, there is provided switching means (not shown) that applies the steady-state reference pressure Pv2 as the reference pressure Pv to be compared with the discharge side pressure Pd.

  In the present embodiment, the electromagnetic valve control means 45 of the suction control means and the signal generation means 40 of the speed control means are described as being separate from each other. The control means 45 and the signal generation means 40 may be a single control means. When the control means having both functions is provided as described above, the reference pressure Pv (Pv1, Pv2), the target pressure Pf (Pf1, Pf2), a timer that counts the elapsed time since the start of the motor, a control signal output unit 46 that outputs a control signal to the electromagnetic valve 34, and a command signal that is output to the inverter 31 A command signal output unit is provided in the control means.

2-3. Pressure detection means The pressure detection means described above, which is a configuration means common to both the speed control means and the suction control means, is a pressure sensor as an example. In the illustrated embodiment, the separator 14 and the fuel consuming device 16 are used. It is provided in a supply passage 63 that communicates with each other, and is configured to detect the pressure Pd of the fuel gas in the supply passage 63.

  However, as long as the pressure detection means 50 can detect the pressure on the discharge side of the compressor main body 10, the fuel is detected at any point between the discharge port 10 b of the compressor main body 10 and the fuel consuming device 16. The gas pressure may be detected, and the arrangement is not limited to the illustrated embodiment.

  The pressure detecting means 50 is a pressure detecting means for detecting the discharge side pressure of the compressor body 10 for the speed control described above, and a pressure detecting means for detecting the discharge side pressure of the compressor body 10 for the suction control. May be provided separately.

  In this way, the pressure of the fuel gas in the supply passage 63 (measured pressure Pd) detected by the pressure detection means 50 is input to the signal generation means 40 and the electromagnetic valve control means 45 described above as an electrical signal.

3. Operation As an example, the fluid compressor 1 including the capacity control device configured as described above has a gas flow path 64 communicated with the suction control valve 33 as a city gas or the like via a gas meter 70 (microcomputer meter) or the like. Connect to the fuel gas supply source.

  The supply passage 63 is connected to a fuel consuming device 16, for example, a power generation gas turbine provided in the cogeneration system, and is supplied from a fuel gas supply source by the operation of the fluid compressor 1. It arrange | positions so that supply to the fuel consumption apparatus 16 is possible after compressing fuel gas.

  The operation of each part of the fluid compressor 1 arranged in this way will be described as follows with reference to the time chart shown in FIG.

3-1. Before starting the compressor body; standby state (T0 to T1)
In the time chart shown in FIG. 2, T0 is a standby state in which the main power source of the fluid compressor 1 (not shown) provided between the power source and the inverter 31 is turned on. Is not ON, the power from the power source is not supplied to the electric motor 15, and therefore the compressor body 10 is also stopped.

  Thus, before the motor 15 is started, the set time t1 by the timer 44 of the signal output means 40 and the set time t2 by the timer 48 of the electromagnetic valve control means 45 are not counted, and the signal generating means 40 switching means. Thus, the target pressure Pf is applied as the steady-state target pressure Pf2, and the reference pressure Pv is applied as the steady-state reference Pv2 by the switching means of the electromagnetic valve control means 45.

  From this, before the start of the electric motor 15 and the compressor body 10, the pressure Pd in the supply passage 63 detected by the pressure detection means 50 is either the above-described start target pressure Pf1 or start reference pressure Pv1. Although the pressure is low, the electromagnetic valve control means 45 does not output a control signal or outputs an OFF control signal, and opens the electromagnetic valve 34 provided in the control pipe 35. ing. However, since the measured pressure Pd in the supply passage 63 is low, the suction control valve 33 opens the suction port 10 a of the compressor body 10.

  Further, the signal output means 40 is in a state where a pressure signal corresponding to the discharge side pressure Pd detected by the pressure detection means 50 and a command signal for the steady-state target pressure Pf2 are output to the inverter 31.

3-2. When starting the compressor body (T1-T3)
As described above, when the start switch is turned on to supply electric power from the power source to the motor 15 and the motor 15 is started (T1) from the state before starting, the compressor main body 10 is also operated and the compressed fluid is compressed. Is started. At this time, the timer 44 of the signal output means 40 and the timer 48 of the electromagnetic valve control means 45 start counting the elapsed time from the activation of the electric motor 15. Simultaneously with the start of the motor 15, the solenoid valve control means 45 switches the reference pressure Pv from the steady-state reference pressure Pv2 to the start-up reference pressure Pv1, and the signal generating means 40 changes the target pressure Pf from the steady-state target pressure Pf2 to the start-up target. Switch to pressure Pf1.

  As a result, the electromagnetic valve control means 45 compares the measured pressure Pd in the supply passage 63 with the startup reference pressure Pv1, and since the measured pressure Pd is equal to or lower than the startup reference pressure Pv1, it is provided in the control pipe 35. The ON control signal for closing the received solenoid valve 34 is output. Accordingly, no compressed fluid is introduced into the closed pressure receiving chamber of the suction control valve 33, and the suction control valve 33 opens the suction port 10a of the compressor body 10.

  In order to improve the startability of the electric motor 15, the electromagnetic valve control means 45 closes the suction port 10 a with the intake control valve 35 immediately after the start to reduce the starting power of the compressor body, and from the start of the electric motor 15. The control signal may not be output to the solenoid valve 34 for a time shorter than the set time t2.

  The command signal output unit 41 of the signal output means 40 is configured so that the above-described start-time target pressure Pf1 and the measured pressure in the supply passage 63 detected by the pressure detection means until the timer 44 counts the elapse of the set time t1. A command signal of a pressure signal corresponding to Pd is output to the inverter 31.

  Since the measured pressure Pd in the supply passage 63 is lower than the startup target pressure Pf1 immediately after the start of the electric motor 15, and thus immediately after the operation of the compressor body 10, the output frequency required by the calculation means of the inverter 31 is The rotation of the motor 15 is increased so that the measured pressure Pd matches the startup target pressure Pf1.

  As the electric motor 15 rotates, the compressor body 10 sucks fuel gas and compresses and discharges it, so that the pressure in the supply passage 63 gradually increases.

  When the measured pressure Pd in the supply passage 63 exceeds the startup target pressure Pf1 (T2), the output frequency obtained by the calculation means of the inverter 31 is set so that the measured pressure Pd matches the startup target pressure Pf1. Then, the rotation of the motor 15 is decelerated, and the motor 15 outputs to the motor 15 an output frequency that shifts to the rotation speed (N1) during the unload operation.

  When the measured pressure Pd rises to a pressure exceeding the starting reference pressure Pv1 due to the pressure increase in the supply passage 63 (T2), the electromagnetic valve control means 45 opens the electromagnetic valve 34 with the control signal turned ON, The compressed fluid in the supply passage 63 is introduced into the closed pressure receiving chamber of the suction control valve 33, the suction port 10a of the compressor body 10 is closed, and the unload operation is started.

  As described above, the startup target pressure Pf1 is set to be relatively low with respect to the steady-state target pressure Pf2, and the startup reference pressure Pv1 is relative to the steady-state reference pressure Pv2. In the conventional capacity control indicated by the broken line because the pressure is set to a low pressure, the pressure Ps in the gas flow passage rapidly decreases and becomes negative pressure as the rotational speed rapidly increases at the time of startup. On the other hand, when the capacity control of the present application is performed, no negative pressure is applied.

  This is because the measured pressure Pd in the supply passage 63 reaches the starting target pressure Pf1 and the starting reference pressure Pv1 in a relatively short time after the start of the compressor body, and shifts to the unload operation. 31 increases the speed of the motor 15 so that the measured pressure Pd matches the startup target pressure Pf1 set relatively low with respect to the steady-state target pressure Pf2. This is because the operation speed of the machine body 10 is increased relatively slowly.

  As a result, it is possible to solve the problem that the temperature of the compressor body 10 suddenly increases when the electric motor 15 is started, and thus the temperature of the discharged compressed fluid suddenly becomes high.

  Further, since the capacity control immediately after the start-up of the electric motor 15 is performed as described above, the pressure on the suction side (in the illustrated example, in the gas flow path 64) of the compressor body 10 is relatively lowered. Since the discharge side pressure Pd of the compressor body 10 reaches the starting target pressure Pf1 and the starting reference pressure Pv1 in a relatively short time and shifts to the unload operation, the suction port 10a of the compressor body 10 As a result, the introduction of the fuel gas to the compressor body 10 is stopped.

  Therefore, when the suction port 10a of the compressor main body 10 is closed, the pressure in the gas flow passage 64 stops decreasing and returns to the pressure before the compressor main body 10 is started. For example, a gas meter 70 (microcomputer meter) Even when the fluid compressor 1 is disposed on the downstream side of the gas meter 70, malfunction of the gas meter 70 caused by a sudden pressure drop on the suction side of the compressor body 10 when the compressor body is started up, or damage to the gas meter 70 Etc. can be suitably prevented.

  In this way, after the measured pressure Pd in the supply passage 63 reaches the starting target pressure Pf1 and the starting reference pressure Pv1, the above-described time until the elapse of the set times t1 and t2 is counted by the timer 44. The capacity control based on the start target pressure Pf1 and the start reference pressure Pv1 is performed, and the aforementioned unload operation state is maintained.

3-3. Steady operation (after T3)
When the elapsed time from the start of the electric motor 15 counted by the timer 44 provided in the signal generating means 40 has passed the set time t1 (T3), the switching means of the command signal output unit 41 sets the target pressure Pf as described above. The steady-state target pressure Pf2 is applied in place of the starting target pressure Pf1, and a target pressure signal corresponding to the steady-state target pressure Pf2 is output to the inverter 31 together with the pressure signal for the measured pressure Pd as the command signal.

  When the elapsed time counted by the timer 48 has passed the set time t2, the switching means of the control signal output unit 46 uses the above-mentioned startup reference as the reference pressure Pv for comparison with the measured pressure Pd. Instead of the pressure Pv1, the steady-state reference pressure Pv2 is applied (T3).

  By switching between the reference pressures Pf and Pv, the measured pressure Pd in the supply passage 63 becomes lower than both the steady-state target pressure Pf2 and the steady-state reference pressure Pv2. The inverter 31 that has received the pressure signal from the output unit 41 and the command signal of the target pressure signal changes the output frequency to be output to the motor 15 so that the measured pressure Pd matches the steady-state target pressure Pf2. The number of revolutions of 15 is increased to the rated number of revolutions (T4).

  In addition, since the suction port 10a of the compressor body 10 opens and the introduction of the fuel gas into the compressor body 10 is started again after the predetermined time t2, the pressure Ps in the gas flow path 64 decreases. Since the discharge side pressure Pd of the compressor main body 10 has already increased to the startup target pressure Pv1, the increase in the rotation speed of the electric motor 15 by the inverter 31 causes the discharge side pressure of the compressor main body 10 to increase from P0 to Pf2 at a time. Compared with the case where it is raised up to, it is performed more slowly. For this reason, the pressure drop on the suction side of the compressor body also becomes gentle, and it is possible to prevent the gas meter (microcomputer meter) from malfunctioning due to the start of steady operation.

  Further, the control signal output unit 46 of the electromagnetic valve control means 45 outputs a control signal for closing the electromagnetic valve 34 provided in the control pipe 35, and compresses the suction control valve 33 in the supply passage for the closed pressure receiving chamber. The introduction of the fluid is stopped, the suction port 10a of the compressor body 10 is opened, and the compression of the fuel gas is started (T3).

  Thus, when the measured pressure Pd in the supply passage 63 exceeds the steady-state target pressure Pf2 and the steady-state reference pressure Pv2 (T5), a pressure signal for the discharge-side pressure Pd that has increased in pressure is received as a command signal. The inverter 31 outputs an output frequency for decelerating the rotation of the electric motor 15 to the electric motor 15 so that the measured pressure Pd matches the startup target pressure Pf1 by the arithmetic circuit, and the rotation of the electric motor N1 during the unload operation is output. To lower.

  Further, the electromagnetic valve control means 45 opens the electromagnetic valve 34 provided in the control pipe 35 by turning off the control signal, and introduces the compressed fluid from the supply passage 63 to the closed pressure receiving chamber of the suction control valve 33. The suction port 10a of the compressor body 10 is closed, and the operation proceeds to the unload operation.

  Thereafter, the unloading operation is continued until the fuel gas supplied via the supply passage 63 is started by the gas turbine which is the fuel consuming device 16, and the fuel gas is consumed by the fuel consuming device 16. When started, the measured pressure Pd in the supply passage changes according to the consumption of the fuel gas, and accordingly, the pressure signal from the command signal generator 41 of the signal generator 40 and the command signal of the target pressure signal are changed. The received inverter 31 controls the number of revolutions of the motor 15 so that the measured pressure Pd in the supply passage 63 coincides with the target pressure Pf2 at the steady state, and the control signal output unit 46 of the electromagnetic valve control means 45 A control signal for controlling the opening and closing of the electromagnetic valve 34 is output by comparing the measured pressure Pd in the supply passage 63 and the steady-state reference pressure Pv2 to control the opening and closing of the suction port 10a of the compressor body 10. , Capacity control is performed.

4). Modification Example In the capacity control configured as described above, the motor 15 is connected to the motor 15 regardless of the discharge side pressure Pd of the compressor main body 10 from the start of the motor 15 until a preset time t1 elapses. The compressor is driven at a relatively low rotational speed relative to the rated rotational speed of 15, for example, the unload rotational speed N1, and after the set time t1, the discharge side pressure (pressure in the supply passage 63) of the detected compressor body is detected. Pd) may be controlled to coincide with the target pressure Pf (for example, Pf2 in FIG. 2).

  In this case, instead of the configuration in which the timer 44 is provided in the signal generating means 40 in the embodiment shown in FIG. 1, the timer 44 is provided in the inverter 31 as shown in FIG. When the start of the motor 15 is instructed, the timer 44 provided in the inverter 31 starts counting, and the inverter 31 receives from the signal generating means 40 until the elapse of the set time t1 is counted by the timer 44. Regardless of the signal, the frequency output to the motor 15 is controlled so that the rotation speed is set in advance as a relatively low rotation speed relative to the rated rotation speed of the motor 15, for example, the unload rotation speed N1 described above.

  When the elapsed time of the set time t1 is counted by the timer 44, the inverter 31 changes the frequency output to the motor 15 in accordance with the command signal received from the signal generating means 40.

  Thus, in the above modification, the rotation speed set in the inverter 31 (for example, the aforementioned unload rotation speed N1) is maintained until the timer 44 provided in the inverter 31 counts the set time t1. Since the frequency output to the electric motor 15 is controlled as described above, the storage unit 43 of the signal generator 40 is a single unit corresponding to the steady-state target pressure Pf2 in the embodiment described with reference to FIGS. Only one target pressure needs to be stored, and the command signal output unit 41 only needs to output a pressure signal and a target pressure signal corresponding to the single target pressure, and stores a plurality of target pressures. Thus, it is not necessary to provide switching means for switching the target pressure signal to be output.

  Furthermore, as another modification example, the speed of change in frequency output from the inverter 31 to the motor 15 from the start of the motor 15 to the elapse of a preset time t1 is set to the motor 15 after the set time t1. 2 may be relatively gentle with respect to the speed of the change in frequency output (the slope between T1 and T2 of the frequency curve in FIG. 2 is gentler than the slope between T3 and T4).

  Also in this case, as shown in FIG. 3, the timer 44 is provided in the inverter 31 as shown in FIG. 3, instead of the configuration in which the timer 44 is provided in the signal generating means 40 in the embodiment shown in FIG. When the start of the electric motor 15 is commanded to the inverter 31 by turning ON, the timer 44 provided in the inverter 31 starts counting, and until the elapse of the set time t1 is counted by the timer 44, the inverter 31 is counted. When the speed of the motor 15 is controlled at the above-described relatively slow frequency change speed, and the elapsed time of the set time t1 is counted by the timer 44, the speed control of the motor 15 is performed at a relatively rapid frequency change speed. To be able to perform.

  Therefore, also in the above modification, the storage unit 43 of the signal generation unit 40 stores only a single target pressure corresponding to the steady-state target pressure Pf2 in the embodiment described with reference to FIGS. 1 and 2. The command signal output unit 41 may output the pressure signal and the target pressure signal corresponding to the target pressure, and does not need to include a target pressure signal switching unit.

  In the embodiment described above, the fluid compressor provided with the capacity control device of the present invention has been described as being used for the compression of fuel gas. However, the capacity control device of the present invention is capable of compressing air. It can also be used to control the capacity of air compressors and other fluid compressors.

  In particular, when the capacity control device of the present invention is used for the capacity control of the air compressor described above, the compressed air in the receiver tank is purged when the air compressor is stopped. Since there is no difference between the pressure in the cylinder of the compressor main body and the pressure in the receiver tank, the lubricating oil in the receiver tank is not introduced into the compressor main body. As the target pressure at the time of intake and the reference pressure at the time of suction control, a pressure relatively lower than the target or reference pressure used in the steady state is applied. The compressor body can be started at a low rotational speed, and can be shifted to the unload rotational speed N1 in a relatively short time, so that the frictional heat between the rotors and the compression heat of the fluid to be compressed can be kept low. It can have become damaged or the rotor, and that the emergency stop of the fluid compressor with a rapid temperature rise in the compressed fluid can be suitably prevented.

  In the above embodiment, the oil-cooled type is used as the compressor body, but the fluid compressor to which the capacity control device of the present invention is applied is the above-described oil-free compressor as the compressor body. It may be used. Such an oil-free compressor rotates the rotor at a higher speed than the oil-cooled compressor as described above. Since it causes a rapid temperature rise of the rotor and the compressed fluid more than the machine, by performing start-up control with the capacity control device of the present invention, suppressing a sudden increase in the rotational speed of the compressor body, This is effective in preventing damage to the compressor body and other problems.

  The fluid compressor start-up control method of the present invention and the capacity control device of the present invention that implements the start-up control method are applied to various fluid compressors that may cause adverse effects when the compressor body operates at high speed during start-up. be able to.

  In particular, at the time of starting the compressor body, it is possible to prevent a pressure drop on the suction side of the compressor body rapidly and excessively, and it is possible to prevent malfunction or breakage of equipment provided on the suction side of the compressor body. Therefore, for example, it is suitable to be incorporated into a device that operates using, for example, city gas supplied through a gas meter (microcomputer meter) as a fuel, for example, a co-generation system.

BRIEF DESCRIPTION OF THE DRAWINGS Schematic explanatory drawing of the fluid compressor provided with the capacity | capacitance control apparatus of this invention. The time chart which shows operation | movement of the fluid compressor provided with the capacity | capacitance control apparatus of this invention. The schematic explanatory drawing of the fluid compressor provided with another capacity | capacitance control apparatus of this invention. Schematic explanatory drawing which shows the basic composition of the conventional fluid compressor.

Explanation of symbols

1 Fluid compressor (fuel compressor)
DESCRIPTION OF SYMBOLS 10 Compressor body 10a Suction port 10b Discharge port 10c Refueling port 12 Receiver tank 14 Separator 15 Electric motor 16 Fuel consumption equipment (gas turbine)
DESCRIPTION OF SYMBOLS 20 Capacity control device 31 Inverter 33 Suction control valve 34 Electromagnetic valve 35 Control piping 40 Signal generation means 41 Command signal output part 43 Memory | storage part 44 Timer 45 Electromagnetic valve control means 46 Control signal output part 47 Memory | storage part 48 Timer 50 Pressure detection means ( Pressure sensor)
61 Discharge passage 62 Oil supply passage 63 Supply passage 64 Gas flow passage 70 Gas meter (microcomputer meter)

Claims (6)

Based on the detected discharge side pressure of the compressor main body and a preset target pressure, the frequency input to the motor driving the compressor main body is changed so that the discharge side pressure matches the target pressure. Speed control for controlling the operation speed of the compressor body, and comparing the detected discharge side pressure of the compressor body with a preset reference pressure, and the detected discharge side pressure of the compressor body The suction opening of the compressor body is opened when the reference pressure or lower, and when the discharge side pressure of the compressor body exceeds the reference pressure, the suction control of closing the suction port of the compressor body is included.
As the target pressure, a steady-state target pressure and a startup target pressure set relatively low with respect to the steady-state target pressure are set in advance,
The speed control is performed using the startup target pressure as the target pressure from the start of the electric motor until the preset set time elapses, and after the set time elapses, the steady-state target pressure is used as the target pressure. There line speed control,
As the reference pressure, a normal reference pressure and a starting reference pressure set relatively low with respect to the normal reference pressure are set,
The suction control is performed using the startup reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and after the set time elapses, the steady-state reference pressure is used as the reference pressure. capacity control method of a fluid compressor, characterized in row Ukoto inhalation control. Based on the detected discharge side pressure of the compressor main body and a preset target pressure, the frequency input to the motor driving the compressor main body is changed so that the discharge side pressure matches the target pressure. Speed control for controlling the operation speed of the compressor body, and comparing the detected discharge side pressure of the compressor body with a preset reference pressure, and the detected discharge side pressure of the compressor body The suction opening of the compressor body is opened when the reference pressure or lower, and when the discharge side pressure of the compressor body exceeds the reference pressure, the suction control of closing the suction port of the compressor body is included.
From the start of the motor to the elapse of a preset set time, a frequency that is set to a constant rotational speed set relatively low with respect to the rated rotational speed of the electric motor is input to the electric motor without performing the speed control. while, after the course of the set time, have rows the speed control,
As the reference pressure, a normal reference pressure and a starting reference pressure set relatively low with respect to the normal reference pressure are set,
The suction control is performed using the startup reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and after the set time elapses, the steady-state reference pressure is used as the reference pressure. capacity control method of a fluid compressor, characterized in row Ukoto inhalation control. Based on the detected discharge side pressure of the compressor body and a preset target pressure, the frequency input to the electric motor that drives the compressor body is gradually adjusted so that the discharge side pressure matches the target pressure. To control the operation speed of the compressor body by changing the pressure, and comparing the detected discharge side pressure of the compressor body with a preset reference pressure, and detecting the detected discharge side of the compressor body Including suction control for opening the suction port of the compressor body when the pressure is equal to or lower than the reference pressure, and closing the suction port of the compressor body when the discharge side pressure of the compressor body exceeds the reference pressure. ,
As the change rate of the frequency, a change rate at the time of steady state and a change rate at the time of start-up where the rate of change is relatively slow with respect to the change rate at the steady state are set in advance,
From the start-up of the motor to the elapse of a preset set time, the frequency is changed at the change speed at the start-up, and after the set time has elapsed, the frequency is changed at the steady-state change speed ,
As the reference pressure, a normal reference pressure and a starting reference pressure set relatively low with respect to the normal reference pressure are set,
The suction control is performed using the startup reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and after the set time elapses, the steady-state reference pressure is used as the reference pressure. A method for controlling the capacity of a fluid compressor, wherein suction control is performed . Based on the discharge side pressure of the compressor main body detected by the pressure detection means and a preset target pressure, an input is made to the electric motor that drives the compressor main body so that the discharge side pressure matches the target pressure. A speed control means for controlling the operating speed of the compressor main body by changing the frequency of the compressor, and comparing the discharge side pressure of the compressor main body detected by the pressure detecting means with a preset reference pressure, and detecting the detected pressure. When the discharge side pressure of the compressor body is equal to or lower than the reference pressure, the suction port of the compressor body is opened, and when the discharge side pressure of the compressor body exceeds the reference pressure, the suction of the compressor body Including inhalation control means for closing the mouth ,
The speed control means includes a storage means for storing a steady-state target pressure as the target pressure and a startup target pressure set relatively low with respect to the steady-state target pressure;
The startup target pressure stored in the storage means is applied as the target pressure from the start of the electric motor to the elapse of a preset set time, and the steady-state target pressure is set to the target pressure after the set time elapses. have a switching means for applying a target pressure,
The suction control means has a storage means for storing a steady-state reference pressure and a starting reference pressure set relatively low with respect to the steady-state reference pressure as the reference pressure;
Switching means for applying the starting reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and applying the steady-time reference pressure as the reference pressure after the set time elapses capacity control device for a fluid compressor, characterized by have a. Based on the discharge side pressure of the compressor main body detected by the pressure detection means and the preset target pressure, the compressor main body is driven so that the discharge side pressure matches the preset target pressure. Speed control means for controlling the operating speed of the compressor body by changing the frequency input to the electric motor, and comparing the discharge side pressure of the compressor body detected by the pressure detection means with a preset reference pressure, When the detected discharge side pressure of the compressor body is equal to or lower than the reference pressure, the suction port of the compressor body is opened, and when the discharge side pressure of the compressor body exceeds the reference pressure, the compressor Including suction control means for closing the suction port of the main body ,
The speed control means inputs, to the electric motor, a frequency that is set to a constant rotational speed set relatively low with respect to the rated rotational speed of the electric motor from the start of the electric motor to the elapse of a preset set time. together, have a switching means for inputting after of the set time, the drive signal of the discharge pressure of the detected compressor body closer to the target pressure to said electric motor,
The suction control means has a storage means for storing a steady-state reference pressure and a starting reference pressure set relatively low with respect to the steady-state reference pressure as the reference pressure;
Switching means for applying the starting reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and applying the steady-time reference pressure as the reference pressure after the set time elapses capacity control device for a fluid compressor, characterized by have a. Based on the discharge side pressure of the compressor main body detected by the pressure detection means and the preset target pressure, the compressor main body is driven so that the discharge side pressure matches the preset target pressure. Speed control means for controlling the operation speed of the compressor body by gradually changing the frequency input to the motor, and comparing the discharge side pressure of the compressor body detected by the pressure detection means with a preset reference pressure When the detected discharge side pressure of the compressor body is equal to or lower than the reference pressure, the suction port of the compressor body is opened, and when the discharge side pressure of the compressor body exceeds the reference pressure, Including suction control means for closing the suction port of the compressor body ,
The speed control means has storage means for storing a change speed at a steady time and a change speed at a start-up time at which the speed of change is relatively slow relative to the change speed at the steady time as the change speed of the frequency. With
From the start-up of the motor to the elapse of a preset set time, the change rate at the start stored in the storage means as the change rate of the frequency is applied, and the change at the steady state after the set time elapses Switching means for applying the speed ,
The suction control means has a storage means for storing a steady-state reference pressure and a starting reference pressure set relatively low with respect to the steady-state reference pressure as the reference pressure;
Switching means for applying the starting reference pressure as the reference pressure from the start of the electric motor to the elapse of a preset set time, and applying the steady-time reference pressure as the reference pressure after the set time elapses capacity control device for a fluid compressor, characterized in Rukoto to have a.

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