WO2020213353A1 - 気体圧縮機 - Google Patents

気体圧縮機 Download PDF

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Publication number
WO2020213353A1
WO2020213353A1 PCT/JP2020/013114 JP2020013114W WO2020213353A1 WO 2020213353 A1 WO2020213353 A1 WO 2020213353A1 JP 2020013114 W JP2020013114 W JP 2020013114W WO 2020213353 A1 WO2020213353 A1 WO 2020213353A1
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WO
WIPO (PCT)
Prior art keywords
compressor
gas
pressure
current value
gas compressor
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Ceased
Application number
PCT/JP2020/013114
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English (en)
French (fr)
Japanese (ja)
Inventor
謙次 森田
正彦 高野
征和 長谷
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Hitachi Industrial Equipment Systems Co Ltd
Original Assignee
Hitachi Industrial Equipment Systems Co Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Hitachi Industrial Equipment Systems Co Ltd filed Critical Hitachi Industrial Equipment Systems Co Ltd
Priority to JP2021514842A priority Critical patent/JP7267407B2/ja
Priority to US17/601,937 priority patent/US11994138B2/en
Priority to CN202080027106.4A priority patent/CN113728163B/zh
Publication of WO2020213353A1 publication Critical patent/WO2020213353A1/ja
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D25/00—Pumping installations or systems
    • F04D25/02—Units comprising pumps and their driving means
    • F04D25/06—Units comprising pumps and their driving means the pump being electrically driven
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D17/00—Radial-flow pumps, e.g. centrifugal pumps; Helico-centrifugal pumps
    • F04D17/08—Centrifugal pumps
    • F04D17/10—Centrifugal pumps for compressing or evacuating
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04B—POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS
    • F04B49/00—Control, e.g. of pump delivery, or pump pressure of, or safety measures for, machines, pumps, or pumping installations, not otherwise provided for, or of interest apart from, groups F04B1/00 - F04B47/00
    • F04B49/06—Control using electricity
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/08—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by varying the rotational speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/24—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids characterised by using valves controlling pressure or flow rate, e.g. discharge valves or unloading valves
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04C—ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; ROTARY-PISTON, OR OSCILLATING-PISTON, POSITIVE-DISPLACEMENT PUMPS
    • F04C28/00—Control of, monitoring of, or safety arrangements for, pumps or pumping installations specially adapted for elastic fluids
    • F04C28/28—Safety arrangements; Monitoring
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/004—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by varying driving speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/007—Conjoint control of two or more different functions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/009—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by bleeding, by passing or recycling fluid
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0207—Surge control by bleeding, bypassing or recycling fluids
    • F04D27/0223—Control schemes therefor
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0253—Surge control by throttling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0261—Surge control by varying driving speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/02—Surge control
    • F04D27/0284—Conjoint control of two or more different functions
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F04—POSITIVE - DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
    • F04D—NON-POSITIVE-DISPLACEMENT PUMPS
    • F04D27/00—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids
    • F04D27/003—Control, e.g. regulation, of pumps, pumping installations or pumping systems specially adapted for elastic fluids by throttling
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F05—INDEXING SCHEMES RELATING TO ENGINES OR PUMPS IN VARIOUS SUBCLASSES OF CLASSES F01-F04
    • F05D—INDEXING SCHEME FOR ASPECTS RELATING TO NON-POSITIVE-DISPLACEMENT MACHINES OR ENGINES, GAS-TURBINES OR JET-PROPULSION PLANTS
    • F05D2270/00—Control
    • F05D2270/30—Control parameters, e.g. input parameters
    • F05D2270/335—Output power or torque
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
    • Y02B30/00—Energy efficient heating, ventilation or air conditioning [HVAC]
    • Y02B30/70—Efficient control or regulation technologies, e.g. for control of refrigerant flow, motor or heating

Definitions

  • the present invention relates to a gas compressor and relates to a gas compressor that controls unload operation.
  • a gas compressor that generates a compressed gas by supplying a liquid such as oil or water to a compression chamber that compresses the suction gas is known.
  • a refueling type air compressor in which the gas to be compressed is air and the liquid to be supplied is oil will be described as an example.
  • the capacity control of the air compressor can be roughly divided into two types.
  • One is pressure fluctuation capacity control that detects the amount of air consumed by the amount of pressure fluctuation of the discharge line pressure and reduces the power consumption at the time of partial load.
  • the other is constant pressure capacity control that keeps the discharge line pressure constant and controls the compressor rotation speed according to the increase or decrease in the amount of air consumed.
  • the pressure fluctuation capacity control is used for an air compressor not equipped with an inverter, and the rotation speed of the compressor body is constant (hereinafter, may be referred to as a "constant speed machine").
  • the capacity control of the constant speed machine includes suction throttle control that adjusts the opening of the suction throttle valve placed on the intake side of the compressor body and air release control that opens and closes the air release valve placed on the discharge side of the compressor body. There is. Those using one or both of these are known.
  • variable speed machine In constant pressure capacity control, it is used for compressors equipped with an inverter in order to increase or decrease the rotation speed of the compressor body (hereinafter, it may be referred to as "variable speed machine").
  • the inverter operates at a high speed until the pressure set as a target is reached, and when the pressure exceeds the set pressure, the inverter performs a variable speed operation in which the rotation speed is reduced. For example, if the amount of compressed air used on the user side is large and the discharge pressure on the user side is lower than the target pressure, the vehicle operates at the rated maximum rotation speed, and eventually the amount used on the user side decreases and the discharge pressure on the user side becomes higher. When the target pressure is exceeded, the number of revolutions is reduced to save energy.
  • Patent Document 1 PID control operation is performed based on the target pressure (P0), but P0 is maintained as the amount of air used on the user side decreases and the discharge pressure on the user side increases toward P0. Control to reduce the number of revolutions.
  • P1 target pressure
  • P1 upper limit pressure
  • P1 upper limit pressure
  • the compressed air on the upstream side of the discharge port on the user side is released to the atmosphere while the rotation speed is at the lower limit rotation speed.
  • the pressure inside the oil separation tank is often used as the supply pressure of the lubricating oil.
  • the action of the oil supplied to the compression working chamber includes a cooling action of the compressed gas, a sealing action of preventing compression leakage inside the compression mechanism, and a lubrication action of reducing the internal friction of the compression mechanism.
  • the lubricating oil cools the compressed air, seals and lubricates the rotors or the bore surface of the rotor and the casing of the compressor body.
  • Inverter-controlled refueling air compressors usually perform variable speed control, but it is also possible to keep the output frequency from the inverter constant and use it in the same way as a constant speed compressor. is there. That is, it is possible to perform both variable speed control such as P, PI, and PID and constant speed control in which the rotation speed of the electric motor is constant with a refueling compressor equipped with an inverter. In such a case, the internal pressure of the oil separation tank in the unload control, that is, the control pressure may not be the same between the variable speed control and the constant speed control. In either case, the oil supplied to the compressor body is insufficient. There is also a risk of doing so. In a gas compressor, a technique capable of making the control pressure variable and ensuring an appropriate control pressure during unload control is desired.
  • the compressor main body that compresses the gas and discharges the compressed gas
  • the electric motor that supplies the driving force to the compressor body
  • the power conversion device that supplies the predetermined frequency power to the electric motor
  • the suction side of the compressor main body are arranged. It has at least one of the suction throttle valve and the air release valve that discharges the compressed gas of the discharge piping system to the atmospheric pressure environment, and a control device, and when the discharge pressure reaches a predetermined pressure, the suction throttle valve is closed or the air is released.
  • a gas compressor that performs unload operation to reduce the load on the compressor body by opening the valve, and detects a current value input to the power converter and outputs a current value detector to the control device.
  • the control device opens the suction throttle valve or closes the air release valve to obtain a predetermined upper limit current higher than the lower limit current value.
  • the suction throttle valve is closed or the air release valve is opened.
  • a compressor main body that compresses a gas and discharges a compressed gas
  • an electric motor that supplies a driving force to the compressor body
  • a power converter that supplies a predetermined frequency power to the electric motor
  • the compressor has at least one of a suction throttle valve arranged on the suction side of the main body and an air release valve that discharges the compressed gas of the discharge piping system to the atmospheric pressure environment, and a control device, and when the discharge pressure reaches a predetermined pressure, the suction throttle valve
  • a gas compressor that performs an unload operation that reduces the load on the compressor body by closing the valve or opening the air release valve. It detects the pressure of the gas discharged from the compressor body and outputs it to the control device.
  • the control device opens the suction throttle valve or closes the air release valve to obtain a predetermined pressure higher than the lower limit pressure.
  • the suction throttle valve is closed or the air release valve is opened.
  • a compressor main body that compresses the gas and discharges the compressed gas, an electric motor that supplies the driving force to the compressor body, a power conversion device that supplies a predetermined frequency power to the electric motor, and a discharge piping system. It has an air release valve that discharges the compressed gas into the atmospheric pressure environment and a control device, and closes the suction throttle valve or the air release when the discharge pressure reaches a predetermined pressure.
  • a gas compressor that performs an unload operation by opening a valve to reduce the load on the compressor body, has a plurality of the air release systems, and arranges the air release valves for each of the plurality of air exhaust systems. Further, a pressure regulating valve having different opening and closing pressures is provided on the downstream side of each of the air release valves, and the control device selects one of the air release valves to perform the unload operation. Is.
  • control pressure can be made variable and an appropriate control pressure can be secured.
  • Other problems, configurations, and effects of the present invention will be clarified from the following description.
  • FIG. 1 shows the structure of the refueling type air compressor according to Example 1 of this invention. It is a figure which shows the transition of the load / unload control by Example 1.
  • FIG. 2 shows the structure of the refueling type air compressor according to Example 2 of this invention. It is a figure which shows the transition of the load / unload control by Example 2.
  • Example 3 shows the structure of the refueling type compressor according to Example 3 of this invention.
  • FIG. 1 schematically shows the configuration of a conventional refueling type air compressor.
  • the refueling type air compressor 200 (hereinafter, may be referred to as “compressor 200”) has a suction throttle when the compressor body 3 is driven by an electric motor 4 supplied with electric power from an inverter 5 (power converter). Atmospheric air is sucked into the compressor body through the valve 2. The sucked atmospheric air is boosted by the compressive action of the compressor main body 3, and the compressed air of a predetermined pressure is discharged from the discharge port of the compressor main body 3.
  • lubricating oil is supplied to the compression chamber of the compressor main body 3 for cooling the compressed intake air, sealing for preventing air leakage, and lubricating the members, and compressed air mixed with gas and liquid is supplied from the compressor main body 3. It is supposed to be spit out.
  • the compressed air from the compressor body 3 flows into the oil separation tank 6 (liquid separation tank), and the compressed air and the lubricating oil are separated.
  • the compressed air separated in the oil separation tank 6 is cooled by the aftercooler 8 and then sent to the equipment used by the user.
  • the lubricating oil is transferred from the temperature control valve 12 to the compressor main body 3 via the oil filter 14. Refuel.
  • the oil temperature is higher than the threshold value, it flows from the temperature control valve 12 to the oil cooler 13 side, cools the lubricating oil so as to reach a predetermined temperature range, passes through the oil filter 14, and supplies the lubricating oil to the compressor main body 3. It is designed to do.
  • the pressure for circulating the oil separated in the oil separation tank 6 to the compressor body again is the discharge air pressure of the compressor body 3. That is, the lubricating oil is pumped by the internal pressure of the oil separation tank 6.
  • a branch pipe branching to the suction side of the compressor main body 3 is arranged downstream of the air system of the oil separation tank 6, and an air release valve 10 is provided on the pipe line.
  • the air release valve 10 is a valve body that opens and closes in response to a command from the control device 15. When the air release valve 10 is open, the air inside the oil separation tank 6 (air on the upstream side of the check valve 7) is released to the suction side of the compressor main body 3. As a result, the load on the electric motor is reduced and energy saving is realized.
  • a pressure sensor 9 is arranged in the downstream piping of the aftercooler 8.
  • the pressure sensor 9 detects the discharge air pressure of the compressor 200 and outputs the result to the control device 15.
  • the control device 15 monitors the discharge air pressure value, outputs a frequency command value to the inverter 5, and performs overall control such as opening and closing of the air release valve 10.
  • FIG. 1 shows a variable speed machine equipped with an inverter 5, but the configuration of the constant speed machine is such that there is no inverter 5 in FIG. 1 and the control device supplies electric power for constant speed rotation to the motor 4. Except for the points, the configuration is almost the same.
  • Figure 2 shows the time-series change due to "unload control" during constant speed control.
  • the control device 15 closes the suction throttle valve 2 and opens the air release valve 10 to release the pressure in the oil separation tank 6 from the air release valve 10.
  • start air valve control Until the discharge line pressure drops to PL (lower limit pressure), the pressure in the oil separation tank 6 continues to be released, but the orifice (pressure adjustment valve) 11 closes, causing the oil separation tank internal pressure PTL (unload). Stable pressure).
  • the control device 15 opens the suction throttle valve 2 and closes the air release valve 10. As a result, the pressure in the oil separation tank 6 is increased, and the discharge line pressure is increased.
  • the rotation speed of the electric motor 4 is NF and is always constant.
  • FIG. 3 shows a time-series change due to "unload control” by variable speed control (PID control) of the conventional example.
  • the output frequency of the inverter 5 is changed by P, PI, and PID to increase or decrease the rotation speed of the electric motor 4 so that the pressure PC stabilizes (in FIG. 3). Illustrated as decelerating). Even if the rotation speed of the electric motor 4 drops to the lower limit rotation speed NV1, if the consumption of compressed air decreases, the discharge line pressure gradually increases and eventually reaches the pressure PU. When the pressure PU is reached, the internal pressure of the oil separation tank 6 is released from the air release valve 10 to reduce the pressure, as in the constant speed control.
  • Example 1 of the present invention will be described based on the above conventional examples.
  • FIG. 4 shows a refueling type air compressor 100 according to the first embodiment to which the present invention is applied (hereinafter, may be referred to as “compressor 100”).
  • compressor 100 The configuration of is shown.
  • the compressed gas is described as air and the liquid that supplies the compressed gas to the compression chamber is described as oil.
  • the compression medium may be another gas or compression.
  • the liquid supplied to the chamber may be another liquid such as water.
  • the compressor 100 is a package type compressor including a compressor main body 3, an electric motor 4, an inverter 5, an oil separation tank 6, an aftercooler 8, an oil cooler 13, and a control device 15, and stores these in a housing.
  • the compressor body 3 is a positive displacement screw compressor body that generates compressed air by meshing male and female screw rotors that rotate with each other.
  • other positive displacement compressors and rotary compressors can be applied to the present invention.
  • a single screw rotor type or a type using three or more screw rotors may be used, or a multi-stage compressor main body including a plurality of compressor main bodies may be used.
  • the inverter 5 receives electric power from the power source 17, converts it into a predetermined frequency according to a frequency command value from the control device 15, and supplies electric power to the electric motor 4.
  • Various types of electric motors can be applied to the electric motor 4.
  • the output shaft side of the electric motor 4 is directly connected to the screw rotor of the compressor main body 3 or indirectly via a gear, a belt, or the like to supply a driving force to the compressor main body 3.
  • the oil separation tank 6 is a separator that separates oil and water from the compressed air of the gas-liquid mixture (oil and air) discharged from the compressor main body 3 by collision separation, swirl separation, or both.
  • the separated compressed air flows to the discharge piping system and is allowed to flow from the oil separation tank 6 to the downstream side via a check valve 7 and an air-cooled or liquid-cooled aftercooler 8 on the user side (user) of the compressed air. It is designed to be supplied to the side).
  • the control device 15 constitutes various functional units by the cooperation of the arithmetic unit and the program, and controls the entire compressor 100.
  • the control device 15 may be partially or wholly composed of an analog control circuit.
  • the compressor 100 has an oil piping system that returns the oil separated in the oil separation tank 6 to the compressor main body 3.
  • the oil separated from the air in the oil separation tank 6 is returned to the compressor main body 3 by the internal pressure of the oil separation tank 6.
  • the oil piping system includes a temperature control valve 12, an oil cooler 13, and an oil filter 14.
  • the temperature control valve 12 is an electromagnetic three-way valve having a temperature detection function.
  • the outlet to the oil cooler 13 side is opened, and when the temperature is lower than the predetermined temperature, the oil cooler is opened.
  • the outlet on the side bypassing No. 13 the pipeline through which the oil flows is switched, and the oil temperature is controlled within a predetermined temperature range.
  • the compressor 100 includes a suction throttle valve 2 on the suction side of the compressor main body 3.
  • the suction throttle valve 2 is a mechanical or electromagnetic valve body that adjusts the amount of air flowing in from the intake passage of the compressor main body 3. For example, in the "unload control" described later, the suction throttle valve 2 is closed or its opening degree is reduced.
  • the suction throttle valve 2 is a mechanical type, the internal pressure of the oil separation tank 6 (upstream side of the check valve 7) is used as the control pressure. That is, the opening / closing control of the valve body is performed by internal pressure via a control pipe (not shown).
  • the compressor 100 includes a pressure sensor 9 in the discharge piping system on the downstream side of the oil separation tank 6.
  • the pressure sensor 9 is arranged on the downstream side of the check valve 7 to detect the pressure of the compressed air and output the detection result to the control device 15.
  • the control device 15 compares the input pressure from the pressure sensor 9 with the set pressure (selected by the user or held as an initial value), and determines the frequency command to be output to the inverter 5. In this embodiment, it is assumed that the compressor main body 3 is driven by PID control.
  • the compressor 100 is provided with an air release piping system on the downstream side of the oil separation tank 6, and is provided with an air release valve 10A on the air release piping system.
  • the air exhaust piping system communicates with the discharge piping system in terms of air flow and pressure, and the flow of compressed air to the outside is controlled by opening and closing the air exhaust valve 10A.
  • the air release valve 10A is arranged on the air discharge pipe arranged on the downstream side of the oil separation tank 6 and on the upstream side of the check valve 7.
  • the air exhaust piping system is a piping that connects the discharge piping side of the oil separation tank 6 and the suction side of the compressor body (more specifically, the downstream side of the suction filter 1).
  • the air release valve 10A opens and closes in response to a command from the control device 15 in the "unload control” described later, and sends compressed air on the upstream side of the check valve 7 to the atmosphere (primary side of the suction throttle valve 2). It is designed to be released.
  • the compressor 100 includes a current value detector 18 that detects a current value between the power supply 17 and the inverter 5.
  • the current value detector 18 detects the current value when managing the control pressure of the compressor main body in the “unload control” described later, and outputs this to the control device 15. Further, the control device 15 stores in advance correlation information indicating the relationship between the current value and the pressure.
  • the correlation information is information on the current value corresponding to the load applied to the compressor main body 3. For example, when the load (pressure) applied to the compressor body 3 is 0.3 MPh, the current value is IL2, when the pressure is 0.25 MPh, the current value is IL1, and so on.
  • the internal pressure of the oil separation tank 6 pressure on the upstream side of the check valve 7) can be determined from the input of the current value.
  • unload control means that the suction throttle valve 2 is operated when the detected pressure of the pressure sensor 9 reaches the upper limit pressure PU higher than the target pressure PC due to the decrease in the consumption of compressed air.
  • This is a control method in which the power consumption is reduced by closing (suction throttle control) and opening the air release valve 10A (air release control) to reduce the load on the compressor main body 3.
  • the rotation speed of the electric motor 4 is in the state of the minimum rotation speed.
  • the control pressure of the compressor 100 is managed in the "unload control" by monitoring the current value.
  • FIG. 5 shows the time-series change of "unload control” according to the first embodiment.
  • the uppermost stage shows the opening / closing transition of the suction throttle valve 2 and the opening / closing transition of the air release valve 10A
  • the second stage shows the transition of the discharge line pressure detected by the pressure sensor 9
  • the third stage shows the current.
  • the transition of the INV (inverter) input current detected by the value detector 18 is shown
  • the fourth stage shows the rotation speed of the electric motor 4 (corresponding to the output frequency of the inverter 5).
  • the pressure PC indicates the target pressure (set pressure)
  • the pressure PU indicates the upper limit pressure at which "unload control” is started
  • the pressure PL returns from the unload control to "load control”. Indicates the lower limit pressure to be applied.
  • the control device 15 After starting the compressor, the control device 15 outputs a command to the inverter 5 and operates the electric motor 4 at the rated full speed rotation based on a predetermined acceleration rate. As a result, the discharge pressure of the compressor body 3 starts to increase toward the target pressure PC. At this time, the suction throttle valve 2 is open, the air release valve 10A is closed, and the INV input current value is ITC.
  • the control device 15 When the discharge line pressure reaches the PC at time T1, the control device 15 outputs a frequency command value to the inverter 5 so as to maintain the pressure PC by PID control based on the output value of the pressure sensor 9. As a result, the discharge line pressure is maintained based on the pressure PC.
  • the control device 15 starts the "unload” operation. That is, the suction throttle valve 2 is closed to limit the amount of suction air, and the air release valve 10A is opened to release the compressed air of the oil separation tank 6 (downstream from the check valve 7) to the atmospheric pressure environment. As a result, the internal pressure of the oil separation tank 6 is rapidly reduced, the load on the compressor main body 3 is reduced, and the power consumption can be reduced.
  • the pressure due to the compressed air discharged from the compressor main body 3 as described above is the control pressure of the compressor 100 (the power for returning the separated oil to the compressor main body 3 and the opening / closing power of the suction throttle valve 2). Etc.). Therefore, in order to secure a predetermined control pressure, in this embodiment, the limit of the suction amount and the release of the compressed air are controlled by whether or not the current value detected by the current value detector 18 is lower than the predetermined threshold value. It has become.
  • the control device 15 opens the suction throttle valve 2, closes the air release valve 10A, and raises the internal pressure of the oil separation tank. It is designed to maintain control pressure.
  • the suction throttle valve 2 is closed and the air release valve 10A is opened at time T5 to increase the internal pressure of the oil separation tank.
  • the suction throttle valve 2 is opened again, the air release valve 10A is closed, and the internal pressure of the oil separation tank is increased. That is, the compressor 100 secures the control pressure in the "unload control" by monitoring the INV input current value.
  • the control device 15 switches from "unload control” to "load control". That is, the suction throttle valve 2 is opened, the air release valve 10A is closed (when the pressure is lowered to the lower limit pressure PL when the pressure is already in that state, the current state is maintained), and the inverter 5 is operated at full speed at the rated speed. Outputs the frequency command value of. As a result, the discharge line pressure starts to increase toward the target pressure PC.
  • the internal pressure of the oil separation tank can be managed so as to secure the control pressure.
  • an arbitrary control pressure can be easily set according to various specifications and usage modes of the compressor 100. Also, the control pressure can be reliably secured.
  • the present embodiment uses a compressor with variable speed control by PID as an example
  • the present invention can be applied to a compressor with constant speed control using an inverter 5. That is, to explain using the constant speed control according to the conventional example of FIG. 2, the discharge line pressure becomes the upper limit pressure PU, the suction throttle valve 2 is closed, the air release valve 10A is opened, and "unload operation (motor rotation speed is constant)”. ) ”,
  • the INV input current value reaches the lower limit current value (IL1) corresponding to the predetermined control pressure
  • the suction throttle valve 2 is opened, the air release valve 10A is opened, and then the INV input is performed.
  • the current value detects IL2 the suction throttle valve 2 is closed and the air release valve 10A is opened.
  • a desired control pressure can be secured even with constant speed control.
  • both the suction throttle valve 2 and the air release valve 10A are operated (opened / closed), but only one of the suction throttle valve 2 and the air release valve 10A is opened / closed.
  • the effect of the present invention can be obtained.
  • the upper limit current value and the lower limit current value of the INV input current value are described in the same manner, but constant speed control is possible. It is also possible to set the upper limit current value and the lower limit current value to different values in the shift control.
  • the control device 15 may be provided with a plurality of information indicating the correlation between the pressure and the INV input current, and one of the plurality of correlation information may be selected between the constant speed control and the variable speed control.
  • Example 2 of the present invention will be described.
  • the desired control pressure was secured based on the current value detected by the current value detector 18 in the “unload control”, but in the second embodiment, the internal pressure of the oil separation tank 6 (check valve) was secured.
  • the control pressure of "unload control” is secured by using the detection pressure of the pressure sensor that detects (upstream side of the valve 7).
  • FIG. 6 shows the configuration of the compressor 100 according to the second embodiment. It should be noted that the same reference numerals are used for the same elements as in the first embodiment, and detailed description may be omitted.
  • the compressor 100 includes a pressure sensor 19 on the discharge piping system of the oil separation tank 6 and at a position on the upstream side of the check valve 7.
  • the position of the pressure sensor 19 is not limited to this, and the present invention can be carried out at either the upstream side of the check valve 7 and the discharge side of the compressor main body 3.
  • control device 15 stores the lower limit pressure PTL1 and the upper limit pressure PTL2 higher than the lower limit pressure PTL1 as the pressure threshold value during the "unload control".
  • PTL1 and PTL2 are pressures lower than the discharge line pressure PU, the target pressure PC, and the lower limit pressure PL.
  • FIG. 7 shows the time-series change of "unload control” according to the second embodiment. Similar to the first embodiment, when the discharge line pressure reaches the upper limit pressure PU at the time T3, the control device 15 starts the “unload” operation. The internal pressure of the oil separation tank 6 is rapidly reduced, and the load on the compressor body 3 is reduced.
  • control device 15 opens the suction throttle valve 2 and closes the air release valve 10A to increase the internal pressure of the oil separation tank and maintain the control pressure. ..
  • the suction throttle valve 2 is closed and the air release valve 10A is opened at time T5, the internal pressure of the oil separation tank is lowered again, and at time T6.
  • the suction throttle valve 2 is opened again, the air release valve 10A is closed, and the internal pressure of the oil separation tank is increased. That is, the compressor 100 secures the control pressure in the "unload control" by monitoring the internal pressure of the oil separation tank.
  • the internal pressure of the oil separation tank can be managed so as to secure the control pressure.
  • an arbitrary control pressure can be easily set for various specifications and usage modes of the compressor 100.
  • the control pressure can be reliably secured.
  • the present invention can be applied to a compressor by constant speed control using an inverter 5 as in the first embodiment. That is, to explain using the constant speed control according to the conventional example of FIG. 2, the discharge line pressure becomes the upper limit pressure PU, the suction throttle valve 2 is closed, the air release valve 10A is opened, and "unload operation (motor rotation speed is constant)”. ) ”, When the internal pressure of the oil separation tank reaches the lower limit pressure PTL1, the suction throttle valve 2 is opened, the air release valve 10A is closed, and then when the oil separation internal pressure PTL2 is detected, the suction throttle is throttled. The valve 2 is closed and the air release valve 10A is opened. As a result, a desired control pressure can be secured even with constant speed control.
  • the effect of the present invention can be obtained by opening and closing only one of the suction throttle valve 2 and the air release valve 10A.
  • the upper limit pressure and the lower limit pressure of the oil separation tank internal pressure are set to different values in the constant speed control and the variable speed control. It may be stored in the control device 15 and one of them may be selected.
  • Example 3 of the present invention will be described.
  • the control pressure during “unload control” was managed by monitoring the output values of the current value detector 18 and the pressure sensor 19, but in Example 3, the amount of air released was different.
  • the difference is that it is equipped with two or more air discharge valves and air discharge piping systems, and these can be selectively used.
  • the control using the inverter can be a constant speed or a variable speed (P, PI, PID).
  • the control pressure to be secured may not be the same.
  • the control pressure may be made variable even with the same constant speed or variable speed control. Therefore, in the third embodiment, one of the features is that it is possible to maintain different control pressures.
  • Example 3 will be described with reference to the drawings.
  • the same reference numerals are used for the same elements as in the above embodiment, and detailed description may be omitted.
  • FIG. 8 shows the configuration of the compressor 100 according to the third embodiment.
  • the compressor 100 includes two air exhaust piping systems on the downstream side of the oil separation tank 6, and the air exhaust valve 10A and the orifice (pressure adjusting valve) 11A, and the air exhaust valve 10B and the orifice (in each piping system).
  • a pressure regulating valve) 11B is provided.
  • the air release piping system provided with the air release valve 10A is the air release system for variable speed control
  • the air release piping system equipped with the air release valve 10B is the air release system for constant speed control.
  • the control device 15 opens and closes only the air release valve 10A in the "unload control" during variable speed control, and opens and closes only the air release valve 10B in the "unload control” during constant speed control.
  • Orifices 11A and 11B are mechanical on-off valves that use springs or the like, and are valve bodies that open at a predetermined pressure or higher and close at a predetermined pressure or lower.
  • the orifice 11A and the orifice 11B have different pressures to open (and close) (for example, the pressure at which the orifice 11A opens and closes is higher than that of the orifice 11B).
  • the desired control pressure can be maintained by closing the orifice 11A in the "unload control".
  • the suction throttle valve 2 and the air release valves 10A and 10B are provided, but the present invention can be applied to a compressor having only a suction throttle valve or an air release valve.
  • screw type is taken as an example of the compressor body
  • present invention can be applied to other positive displacement compressors (rotary type, reciprocating type, etc.) and centrifugal type compressors.
  • variable speed control (FIGS. 5, 7, etc.) of the above example, "unload control” is started when the discharge line pressure reaches the upper limit pressure PU, and then the lower limit pressure PL lower than the target pressure PC is applied.
  • the pressure of the lower limit pressure PL is arbitrary and may be set from the target pressure PC or more to less than the upper limit pressure PU.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Sustainable Development (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Positive-Displacement Pumps (AREA)
  • Applications Or Details Of Rotary Compressors (AREA)
PCT/JP2020/013114 2019-04-15 2020-03-24 気体圧縮機 Ceased WO2020213353A1 (ja)

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US17/601,937 US11994138B2 (en) 2019-04-15 2020-03-24 Gas compressor with a plurality of air realease systems each having an air release valve and an air regulating valve
CN202080027106.4A CN113728163B (zh) 2019-04-15 2020-03-24 气体压缩机

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CN116123123B (zh) * 2023-04-04 2023-08-01 亿昇(天津)科技有限公司 一种磁悬浮鼓风机系统的控制方法及磁悬浮鼓风机系统
CN119196060A (zh) * 2024-11-27 2024-12-27 山东豪迈机械制造有限公司 压缩机断电保护方法、装置、系统、压缩机、介质及产品

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US11994138B2 (en) 2024-05-28
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JPWO2020213353A1 (https=) 2020-10-22
JP7267407B2 (ja) 2023-05-01

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