Integrated control type semi-closed screw compressor unit and control method thereof

Abstract

The invention discloses an integrated control type semi-closed screw compressor unit and a control method thereof, and belongs to the technical field of compressor units, the integrated control type semi-closed screw compressor unit comprises a compressor body, a motor and a control device, the control device comprises a CPU and a PLC, the CPU and the PLC are both used for controlling the screw compressor unit, and the motor is used for controlling the screw compressor unit. The control device of the screw compressor unit is integrated on the compressor body, a connecting assembly in an original screw compressor unit is omitted, the control mode is optimized, a compressor body energy adjusting mechanism is omitted, a compressor and an oil pump are integrated with a motor, the overall size and fault points of the screw compressor and the unit are reduced, and the service life of the screw compressor is prolonged. And meanwhile, the assembling and installing steps of the compressor body and the screw compressor unit are greatly simplified, installing and debugging are more convenient, operation is more energy-saving, and safety and reliability are achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of compressor units, and in particular to an integrated control type semi-hermetic screw compressor unit and a control method thereof. Background Art

[0002] A compressor is a driven fluid machine that boosts low-pressure gas to high-pressure gas. Compressors are divided into piston compressors, screw compressors, centrifugal compressors, linear compressors, etc. An oil pump is a machine that transports or pressurizes fluids. Oil pumps are divided into plunger pumps, cycloid pumps, screw pumps, gear pumps, etc.

[0003] During the assembly and use of compressors and units in the prior art, operators need to install the compressor, oil pump and motor separately, and make alignment adjustments, which results in a large workload for on-site assembly. The compressor unit is operated through a control system, but the control system is independently arranged outside the compressor unit, which results in a large space area and infrastructure investment ratio occupied by the control room, and cumbersome on-site engineering installation, wiring and maintenance work. Summary of the invention

[0004] In view of the deficiencies in the prior art, the present invention provides an integrated control type semi-enclosed screw compressor unit and a control method thereof, which solves the problems of large space occupation and complicated installation of the compressor unit.

[0005] The technical solution of the present invention to solve the above technical problems is as follows:

[0006] An integrated control type semi-hermetic screw compressor unit comprises a compressor body and a control device, wherein the control device is connected to the compressor body, the control device comprises a CPU and a PLC programmable controller, the CPU and the PLC programmable controller are bidirectionally connected to control the compressor body;

[0007] The compressor body comprises a motor and a compressor assembly, the motor and the compressor assembly are integrated via a coupling, and the motor, the coupling and the compressor assembly are sequentially connected to form an integral structure.

[0008] By adopting the above technical scheme, the compressor body and the control device of the screw compressor unit are integrated. When the compressor body is configured, the compressor body is connected and integrated with a CPU. The screw compressor unit and the compressor body can be controlled by one CPU. Reducing one CPU can further improve the integration of the screw compressor unit. The control device of the screw compressor unit is integrated on the compressor body, the control method is optimized, the energy adjustment mechanism of the compressor body is cancelled, the overall volume and failure points of the screw compressor and the unit are reduced, and at the same time, the assembly and installation steps of the compressor body and the screw compressor unit are greatly simplified, making installation and commissioning more convenient and the operation more energy-saving, safe and reliable.

[0009] Furthermore, the compressor body includes an oil pump, and the oil pump is coaxially arranged and connected to the motor.

[0010] Furthermore, the control device includes a control console, and a terminal block is provided in the control console; the terminal block is installed in the control console via a guide rail.

[0011] Furthermore, the compressor body and the oil pump are both semi-sealed designs.

[0012] On the other hand, the present invention provides a control method for an integrated control type semi-hermetic screw compressor unit, comprising: the control device comprises an oil pump controller, the oil pump controller is used to generate a pressure signal according to the oil pressure of the oil pump, and transmit the pressure signal to the CPU through a terminal block;

[0013] The CPU reads the pressure signal and processes it according to the preset program logic;

[0014] The PLC programmable controller executes preset logical judgment according to the value of the pressure signal, and outputs a control signal to the control circuit of the oil pump according to the instruction of the CPU to control the start and stop of the oil pump.

[0015] Further, the control device includes an economic controller, which generates a sensing signal according to the temperature of the gas in the pipeline and transmits the sensing signal to the CPU through the terminal block;

[0016] The CPU reads the sensing signal and processes it according to a preset program logic;

[0017] The output module of the PLC programmable controller generates a control signal according to the instruction of the CPU;

[0018] The control signal of the PLC programmable controller is transmitted to the actuator of the expansion valve through a cable or a wire;

[0019] The actuator of the expansion valve adjusts the opening of the expansion valve according to the received control signal.

[0020] Furthermore, the motor is a variable frequency motor, the control device includes a frequency converter controller, the motor and the frequency converter controller are both connected to a sensor, and the sensor is used to collect state information of the motor, generate a state signal and send it;

[0021] The inverter controller receives the status signal, processes it according to a preset algorithm and logic, and generates a control instruction;

[0022] The frequency converter adjusts the output frequency according to the control instruction of the frequency converter controller, thereby changing the speed and torque of the variable frequency motor.

[0023] Furthermore, the PLC programmable controller is communicatively connected to a human-machine interaction HMI, and the human-machine interaction HMI is used to perform manual or automatic control operations to achieve real-time transmission of data and delivery of instructions.

[0024] In summary, compared with the prior art, the above technical solution has the following beneficial effects:

[0025] The integrated control type semi-enclosed screw compressor unit described in the present invention integrates the compressor body and the control device of the screw compressor unit. When the compressor body is configured, the compressor body is connected and integrated with the CPU. The control of the screw compressor unit and the compressor body can be realized through one CPU, which reduces one CPU and further improves the integration of the screw compressor unit; the control device of the screw compressor unit is integrated on the compressor body, the connecting components in the existing screw compressor unit are eliminated, the control mode is optimized, the energy regulating mechanism of the compressor body is eliminated, the compressor and the oil pump are integrated with the motor, the overall volume and failure points of the screw compressor and the unit are reduced, and at the same time, the assembly and installation steps of the compressor body and the screw compressor unit are greatly simplified, so that the installation and debugging are more convenient, and the operation is more energy-saving, safe and reliable. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of the overall structure of a compressor in an embodiment of the present invention;

[0027] Figure 2 A horizontal cross-sectional view of the overall structure of the compressor in an embodiment of the present invention;

[0028] Figure 3 A vertical cross-sectional view of the overall structure of the compressor in an embodiment of the present invention;

[0029] Figure 4 Schematic diagram of the overall structure of the compressor unit in an embodiment of the present invention.

[0030] Explanation of the reference numerals: 1. compressor body; 2. control device; 3. motor; 4. terminal block; 5. control console; 6. male rotor; 7. female rotor; 8. intermediate body; 9. coupling; 10. motor rotor; 11. motor stator; 12. motor cavity; 13. oil pump; 14. terminal block; 15. guide rail. DETAILED DESCRIPTION

[0031] The principles and features of the present invention are described below in conjunction with the accompanying drawings. The examples given are only used to explain the present invention and are not used to limit the scope of the present invention.

[0032] The embodiment of the invention discloses an integrated control type semi-hermetic screw compressor unit.

[0033] Reference Figure 1-Figure 4 An integrated control type semi-hermetic screw compressor unit includes a compressor body 1, a motor 3 and a control device 2, wherein the compressor body 1 and the motor 3 are connected through an intermediate body 8, and the control device 2 is located at the upper part of the motor cavity 12 of the motor 3; the oil pump 13 is connected to the motor 3 through a shell, the control device 2 is located at the upper part of the motor cavity 12 of the compressor motor 3, and the motor stator 11 is arranged inside the motor cavity 12.

[0034] The compressor body 1 includes a male rotor 6 and a female rotor 7, and the motor 3 is a semi-hermetic motor; wherein the male rotor 6 and the female rotor 7 complete the suction, compression and exhaust processes by meshing, and the male rotor 6 is connected to the transmission shaft of the motor rotor 10 of the semi-hermetic motor by means of a coupling 9 or the like. After the power line of the semi-hermetic compressor (i.e., the three-phase power line, the cable required for the operation of the motor 3 in the semi-hermetic compressor) enters the control device 2, it is connected to the semi-hermetic motor through the terminal block 4, and other signals (monitoring, control, regulation, protection, and signals required for operation, such as: suction and exhaust pressure, suction and exhaust temperature, oil supply pressure, oil supply temperature and other signals) are also introduced into the control device 2.

[0035] The oil pump 13 includes a pump rotor, and the motor 3 is a semi-sealed motor; wherein the pump rotor completes the lubricating oil delivery and pressure-increasing process by meshing, and the pump rotor is connected to the transmission shaft of the motor rotor 10 of the semi-sealed motor by means of a coupling 9 or the like. The oil pump power line (i.e., the three-phase power line, the cable required for the operation of the motor 3 in the oil pump) is connected to the semi-sealed motor through the terminal block 4 and introduced into the control device 2. The compressor body 1 includes an oil pump 13, and the oil pump 13 is coaxially arranged and connected to the motor 3. The compressor and the oil pump are both semi-sealed designs.

[0036] The control device 2 includes a CPU and a PLC programmable controller, and the CPU and the PLC programmable controller are used to control the screw compressor unit. By integrating the control device 2 with the compressor body 1, the compressor body 1 and the control device 2 of the screw compressor unit are integrated. When the compressor body 1 is configured, the compressor body 1 is connected and integrated with the CPU, and the control of the screw compressor unit and the compressor body 1 can be realized through one CPU, reducing one CPU, and further improving the integration of the screw compressor unit.

[0037] The control device 2 of the screw compressor unit is integrated into the compressor body 1, and the connecting components in the original screw compressor unit are eliminated, thereby reducing the overall volume of the screw compressor unit, greatly simplifying the installation steps of the compressor body 1 and the screw compressor unit, and reducing the failure points, making installation and debugging more convenient, and the operation more energy-saving, safe and reliable.

[0038] The control device 2 also includes a starter cabinet, a control console 5, an oil pump controller and an economic controller. The starter cabinet, the control console 5, the oil pump controller and the economic controller are integrated into the compressor body 1, which reduces the floor space and space occupied by the starter cabinet in the control room of the machine room without increasing the overall dimensions of the entire compressor unit, and can effectively reduce the overall layout area of ​​the machine room. Especially under the current trend of batch and large-scale application of compressors, the effect of reducing infrastructure scale and material consumption brought about by space saving is becoming more and more obvious.

[0039] The control device 2 includes a control console 5, which is provided with a terminal block 14, a fuse, a current transmitter, a temperature transmitter, an AC contactor, a terminal fixer, an emergency stop switch, and a buzzer; the terminal block 14, the fuse, the current transmitter, the temperature transmitter, the AC contactor, the terminal fixer, the emergency stop switch, and the buzzer are all installed in the control console 5 through a guide rail 15.

[0040] By reducing the distance between the main cable of the unit motor 3 and the starter cabinet, repeated wiring is avoided, thereby greatly reducing the invalid electric energy consumed on the cable in actual operation each year. It also reduces the invalid connection between the main cable, control cable and the starter cabinet inside the unit, greatly reducing the consumption of non-ferrous metal materials.

[0041] It effectively integrates the control system of the entire unit, reduces the duplication and redundancy of the control logic, makes the entire control logic clear and efficient, and can be repaired and diagnosed at the same location when a problem occurs. There is no need to repeatedly run between the machine room and the control room to check various cable lines, which greatly facilitates the maintenance work.

[0042] When the compressor body 1 is a variable frequency motor, the control device 2 also includes a frequency converter controller. When a variable frequency motor is selected, the frequency converter controller can be integrated into the control device 2 of the compressor body 1, which not only reduces the work of external wiring, but also integrates the control and protection functions of the frequency converter. The cable distance between the frequency converter and the motor 3 is short and specially processed, which can effectively reduce the interference of the frequency converter high-frequency harmonics on instruments and other electrical equipment, making the operation safer and more reliable, and can greatly improve the energy efficiency of low-load conditions, bringing significant energy-saving effects.

[0043] The compressor and the unit can be debugged and controlled on site through the human-machine interaction HMI5. This connection method minimizes the external wiring work and reduces the potential faults caused by it, making the operation safer and more reliable. In addition, when a variable frequency motor is selected, the speed of the semi-hermetic motor can be adjusted, the speed of the male rotor 6 and the female rotor 7 can be changed, and then the displacement of the compressor body 1 can be adjusted, which can greatly improve the energy efficiency of low-load conditions and bring significant energy-saving effects.

[0044] The implementation principle of an integrated control type semi-hermetic screw compressor unit in an embodiment of the present invention is as follows: a compressor body 1 and a control device 2 of the screw compressor unit are integrated; when the compressor body 1 is configured, the compressor body 1 is connected and integrated with the CPU, and the control of the screw compressor unit and the compressor body 1 can be realized through one CPU, thereby reducing one CPU and further improving the integration of the screw compressor unit; the control device 2 of the screw compressor unit is integrated on the compressor body 1, the connecting components in the original screw compressor unit are eliminated, the control mode is optimized, the energy regulating mechanism of the compressor body 1 is eliminated, the compressor and the oil pump are integrated with the motor, thereby reducing the overall volume and failure points of the screw compressor and the unit, and at the same time greatly simplifying the assembly and installation steps of the compressor body 1 and the screw compressor unit, making installation and debugging more convenient, and operation more energy-saving, safe and reliable.

[0045] Based on the above compressor unit, the embodiment of the present invention further discloses a control method for an integrated control type semi-hermetic screw compressor unit, wherein the control device 2 comprises an oil pump 13 controller, and the oil pump 13 controller is used to generate a pressure signal according to the oil pressure of the oil pump 13, and transmit the pressure signal to the CPU through the terminal block 14;

[0046] The CPU reads the pressure signal and processes it according to the preset program logic;

[0047] The PLC programmable controller executes a preset logical judgment according to the value of the pressure signal, and outputs a control signal to the control circuit of the oil pump 13 according to the instruction of the CPU to control the start and stop of the oil pump 13.

[0048] The oil pump 13 controller is a monitoring device that detects the oil pressure output by the oil pump 13 in real time. When the oil pressure changes, the oil pump 13 controller generates a corresponding pressure signal. This signal is usually an analog signal (such as a 4-20mA current signal or a 0-10V voltage signal), and its size directly reflects the level of the oil pressure. The pressure signal is transmitted to the CPU through a physical connection (such as a cable) and terminal block 14 for further processing.

[0049] After the CPU receives the pressure signal from the oil pump 13 controller, it will read the value of this signal. According to the preset program logic (such as a specific algorithm or conditional judgment), the CPU will analyze and process this pressure signal. For example, the program may set one or more thresholds to determine whether the oil pressure is within the normal range. If the oil pressure exceeds the preset range, the CPU will make a corresponding decision and prepare to send a control instruction to the PLC.

[0050] After receiving the instruction from the CPU, the PLC will further process it according to the preset logic judgment program. There is a pre-programmed logic inside the PLC, which determines whether the working state of the oil pump 13 needs to be adjusted according to the value of the oil pressure signal. If adjustment is required, the PLC will output a control signal to the control circuit of the oil pump 13. This control signal is usually a digital signal (such as a high level or a low level) used to directly control the start and stop of the oil pump 13.

[0051] After receiving the control signal from the PLC, the control circuit of the oil pump 13 will immediately perform the corresponding operation. If the control signal indicates to start the oil pump 13, the control circuit will turn on the power of the oil pump 13 to start working. If the control signal indicates to stop the oil pump 13, the control circuit will cut off the power of the oil pump 13 to stop working.

[0052] By integrating the oil pump 13 controller, CPU, PLC and oil pump 13 control circuit, the automatic control of the oil pump 13 is realized. This greatly improves the stability and reliability of the system and reduces the need for manual intervention. By accurately controlling the start and stop of the oil pump 13, unnecessary energy waste is avoided. When the system does not require high oil pressure, the oil pump 13 can automatically stop working, thus saving energy. The automated control system can respond more quickly to changes in system requirements and ensure that the oil pump 13 starts immediately when needed, thereby improving production efficiency and equipment utilization. It reduces downtime caused by improper manual operation or equipment failure, and reduces maintenance costs and the risk of equipment damage.

[0053] The control device 2 includes an economic controller, which generates a sensing signal according to the temperature of the gas in the pipeline and transmits the sensing signal to the CPU through the terminal block 14;

[0054] The CPU reads the sensing signal and processes it according to a preset program logic;

[0055] The output module of the PLC programmable controller generates a control signal according to the instruction of the CPU;

[0056] The control signal of the PLC programmable controller is transmitted to the actuator of the expansion valve through a cable or a wire;

[0057] The actuator of the expansion valve adjusts the opening of the expansion valve according to the received control signal.

[0058] The economic controller is a sensor or a combination of sensors used to monitor the temperature of the gas in the pipeline in real time. When the gas temperature changes, the economic controller will generate a corresponding sensing signal. This signal may be an analog signal (such as voltage or current), and its magnitude reflects the high or low temperature of the gas. The sensing signal is transmitted to the CPU through a physical connection (such as a cable) and terminal block 14 for further processing.

[0059] After receiving the sensing signal from the economic controller, the CPU will read the value of this signal. According to the preset program logic (which may be an algorithm or model based on the relationship between temperature and expansion valve opening), the CPU will analyze and process this sensing signal. The CPU will calculate the target expansion valve opening that needs to be adjusted and prepare to send the corresponding control instructions to the PLC.

[0060] After receiving the instructions from the CPU, the PLC will generate a specific control signal according to its internal pre-programmed logic. This control signal is a digital signal used to directly control the action of the expansion valve actuator. The output module of the PLC is responsible for transmitting this control signal to the expansion valve actuator through cables or wires.

[0061] After receiving the control signal from the PLC, the actuator of the expansion valve will adjust the opening of the expansion valve according to the signal instruction. If the control signal indicates to increase the opening, the actuator will adjust the mechanical structure of the expansion valve accordingly to increase its opening, thereby allowing more gas to pass through. If the control signal indicates to decrease the opening, the actuator will decrease the opening of the expansion valve accordingly to limit the flow of gas.

[0062] By monitoring the gas temperature in real time and adjusting the expansion valve opening according to the preset logic, the system can achieve precise control of the gas temperature in the pipeline. This is especially important for application scenarios that require maintaining specific temperature conditions. By properly adjusting the expansion valve opening, the system can optimize energy efficiency and reduce unnecessary energy consumption while ensuring temperature control accuracy. For example, reducing the expansion valve opening when high flow is not required can reduce energy loss.

[0063] The automated temperature control system can quickly respond to temperature changes and adjust the expansion valve opening in time to maintain stable system operation. This helps reduce system performance degradation or failures caused by temperature fluctuations. It reduces downtime caused by improper manual operation or equipment failure, reduces maintenance costs and the risk of equipment damage. At the same time, the automated control system also reduces the requirements for the operator's skill level.

[0064] The motor 3 is a variable frequency motor, the control device 2 includes a frequency converter controller, the motor 3 and the frequency converter controller are both connected to a sensor, and the sensor is used to collect status information of the motor 3, generate a status signal and send it;

[0065] The inverter controller receives the status signal, processes it according to a preset algorithm and logic, and generates a control instruction;

[0066] The frequency converter adjusts the output frequency according to the control instruction of the frequency converter controller, thereby changing the speed and torque of the variable frequency motor.

[0067] The sensor is installed on the motor 3 or its drive system to monitor the status information of the motor 3 in real time, such as speed, current, voltage, temperature, etc. The sensor converts this status information into an electrical signal (i.e., status signal) and sends it to the inverter controller through an appropriate interface.

[0068] After receiving the status signal from the sensor, the inverter controller processes and analyzes the signal to obtain the real-time status of the motor 3. According to the preset algorithms and logic (these algorithms may be based on the physical characteristics of the motor 3, the control objectives and the system requirements), the inverter controller calculates the required control parameters of the motor 3, such as the target speed, target torque, etc. Then, the inverter controller generates corresponding control instructions, which are used to instruct the inverter on how to adjust its output to meet the control requirements of the motor 3.

[0069] After receiving the control instruction from the inverter controller, the inverter adjusts its output frequency and voltage according to the instruction. The output frequency of the inverter directly determines the speed of the motor 3, because the speed of the motor 3 is proportional to the power supply frequency (when the number of pole pairs of the motor 3 remains unchanged). At the same time, the inverter also controls the torque of the motor 3 by adjusting the output voltage. When the voltage / frequency ratio (V / f ratio) is kept constant, it can be ensured that the motor 3 has similar torque characteristics at different speeds. In this way, the inverter can achieve precise control of the speed and torque of the variable frequency motor.

[0070] Due to the use of a closed-loop control system and precise algorithm logic, the system can achieve precise control of the speed and torque of the variable frequency motor. This helps to improve the stability and response speed of the system. By reasonably adjusting the speed and torque of motor 3, the system can reduce unnecessary energy consumption while meeting work requirements. For example, reducing the speed of motor 3 when the load is small can significantly reduce energy consumption. Precise speed and torque control helps to reduce the mechanical and thermal stress of motor 3, thereby extending the service life of motor 3.

[0071] The system can automatically adjust the control parameters of the motor 3 according to different working conditions and load requirements to adapt to various complex application scenarios. Since the system has a high level of automation and intelligence, it can greatly reduce maintenance costs and difficulties. At the same time, the system's fault diagnosis and early warning functions also help to discover and solve problems in a timely manner.

[0072] The PLC programmable controller is communicatively connected to a human-machine interaction HMI, and the human-machine interaction HMI is used to perform manual or automatic control operations to achieve real-time transmission of data and delivery of instructions.

[0073] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An integrated control type semi-hermetic screw compressor unit, characterized in that: The invention comprises a compressor body (1) and a control device (2), wherein the control device (2) is connected to the compressor body (1), and the control device (2) comprises a CPU and a programmable controller (PLC), wherein the CPU and the programmable controller (PLC) are bidirectionally connected and are used to control the compressor body (1); The compressor body (1) comprises a motor (3) and a compressor assembly, wherein the motor (3) and the compressor assembly are integrated via a coupling (9), and the motor (3), the coupling (9), and the compressor assembly are sequentially connected to form an integral structure; The compressor body (1) comprises an oil pump (13), and the oil pump (13) is coaxially arranged and connected to the motor (3).

2. The integrated control type semi-hermetic screw compressor unit according to claim 1, characterized in that: The control device (2) comprises a control console (5), a terminal block (14) is provided in the control console (5), and the terminal block (14) is installed in the control console (5) via a guide rail (15).

3. The integrated control type semi-hermetic screw compressor unit according to claim 1, characterized in that: The compressor body (1) and the oil pump (13) are both of semi-sealed design.

4. A control method for an integrated control type semi-hermetic screw compressor unit according to claim 1, characterized in that: The control device (2) comprises an oil pump controller, wherein the oil pump controller is used to generate a pressure signal according to the oil pressure of the oil pump (13), and transmit the pressure signal to the CPU; The CPU reads the pressure signal and processes it according to the preset program logic; The PLC programmable controller performs preset logic judgment according to the value of the pressure signal, and outputs a control signal to the control circuit of the oil pump (13) according to the instruction of the CPU to control the start and stop of the oil pump (13).

5. The control method of an integrated control type semi-hermetic screw compressor unit according to claim 4, characterized in that: The control device (2) includes an economic controller, which generates a sensing signal according to the temperature of the gas in the pipeline and transmits the sensing signal to the CPU through a terminal block (14); The CPU reads the sensing signal and processes it according to a preset program logic; The output module of the PLC programmable controller generates a control signal according to the instruction of the CPU; The control signal of the PLC programmable controller is transmitted to the actuator of the expansion valve through a cable or a wire; The actuator of the expansion valve adjusts the opening of the expansion valve according to the received control signal.

6. The control method of an integrated control type semi-hermetic screw compressor unit according to claim 4, characterized in that: The motor (3) is a variable frequency motor, the control device (2) comprises a frequency converter controller, the motor (3) and the frequency converter controller are both connected to a sensor, and the sensor is used to collect status information of the motor (3), generate a status signal and send it; The inverter controller receives the status signal, processes it according to a preset algorithm and logic, and generates a control instruction; The frequency converter adjusts the output frequency according to the control instruction of the frequency converter controller, thereby changing the speed and torque of the variable frequency motor.

7. The control method of an integrated control type semi-hermetic screw compressor unit according to claim 4, characterized in that: The PLC programmable controller is communicatively connected to a human-machine interaction HMI, and the human-machine interaction HMI is used to perform manual or automatic control operations to achieve real-time transmission of data and delivery of instructions.

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