A PID control system for an oil-injected screw air compressor

Abstract

The utility model relates to the field of oil injection screw rod air compressor, specifically relates to an oil injection screw rod air compressor PID control system, including main motor and controller, controller signal connection has frequency changer, frequency changer electric connection main motor, and the main motor output shaft is fixed with bipolar compression host through the shaft coupling, and the bipolar compression host pipeline connection has air filter subassembly and oil -gas separation subassembly, oil -gas separation subassembly pipeline connection has lubricating oil small circulation subassembly and cooling assembly, set up lubricating oil big circulation subassembly between lubricating oil small circulation subassembly and cooling assembly, cooling assembly electric connection controller, the utility model has the advantages of: the circulation path of low temperature lubricating oil is greatly shortened, that is, the required time of low temperature lubricating oil circulating to the compression host can be greatly shortened, which is beneficial to the starting rate of the compression host.

Description

Technical Field

[0001] This utility model relates to the field of oil-injected screw air compressors, and more specifically to a PID control system for an oil-injected screw air compressor. Background Technology

[0002] In air compressor systems, PID controllers are mainly used to achieve constant pressure control. By automatically adjusting the output frequency, the system pressure is stabilized at the set value. Specifically, the PID controller outputs a control quantity based on the deviation between the target value and the feedback value through proportional, integral, and derivative operations, which is used to adjust the operating state of the air compressor.

[0003] In conventional oil-injected screw air compressor PID control systems, the low-temperature lubricating oil during compressor startup and the high-temperature lubricating oil after a period of operation are usually circulated through the same pipeline. Since the high-temperature oil needs to be cooled by a cooler, a longer pipeline is required. This results in an excessively long circulation path for the low-temperature lubricating oil, meaning that it takes a long time to circulate to the compressor, which affects the compressor's startup speed and requires further improvement.

[0004] Therefore, it is necessary to invent a PID control system for an oil-injected screw air compressor. Utility Model Content

[0005] Therefore, this utility model provides a PID control system for an oil-injected screw air compressor to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, this utility model provides the following technical solution: a PID control system for an oil-injected screw air compressor, comprising a main motor and a controller, the controller being signal-connected to a frequency converter, the frequency converter being electrically connected to the main motor, the output shaft of the main motor being fixed to a dual-stage compressor main unit via a coupling, the dual-stage compressor main unit being connected via pipes to an air filter assembly and an oil-gas separation assembly, the oil-gas separation assembly being connected via pipes to a lubricating oil small circulation assembly and a cooling assembly, a lubricating oil large circulation assembly being provided between the lubricating oil small circulation assembly and the cooling assembly, and the cooling assembly being electrically connected to the controller.

[0007] Preferably, the air filtration assembly includes an intake valve, the dual-stage compressor main unit is connected to the intake valve via a pipe, the intake valve is connected to an air filter via a pipe, and the air filter is connected to an air inlet via a pipe.

[0008] Preferably, the oil-gas separation assembly includes an oil-gas separator, an oil-gas mixture inlet is fixedly connected to the middle of the oil-gas separator, the dual-stage compressor host pipe is connected to the oil-gas mixture inlet, a lubricating oil outlet is also fixedly connected to the middle of the oil-gas separator, and an exhaust port and an oil return port are also fixedly connected to the top of the oil-gas separator.

[0009] Preferably, the lubricating oil small circulation assembly includes a first lubricating oil pipe, one end of which is fixedly connected to a lubricating oil outlet, and the other end of which is fixedly connected to a temperature control valve. The temperature control valve is fixedly connected to a second lubricating oil pipe, and the second lubricating oil pipe is fixedly connected to a lubricating oil filter. The lubricating oil filter is connected to the bipolar compressor host pipeline.

[0010] Preferably, a safety valve is connected to the top pipe of the oil-gas separator.

[0011] Preferably, the cooling assembly includes a fan and a cooler, and the fan is electrically connected to a controller.

[0012] Preferably, the exhaust port is fixedly connected to an exhaust pipe, the exhaust pipe is connected to the input end of the cooler, and the output end of the cooler is fixedly connected to a compressed air outlet.

[0013] Preferably, the lubricating oil circulation assembly includes a third lubricating oil pipe, one end of which is fixedly connected to a temperature control valve, and the other end of which is fixedly connected to a cooler. The cooler is also fixedly connected to a fourth lubricating oil pipe, which is fixedly connected to the body of the second lubricating oil pipe.

[0014] Preferably, the oil return port is fixedly connected to an oil return pipe, the oil return pipe is fixedly equipped with a one-way valve, and the oil return pipe is connected to the pipeline of the dual-stage compressor main unit.

[0015] The beneficial effects of this utility model are as follows: By using the main motor, controller, frequency converter, host, air filter assembly, oil-gas separation assembly, lubricating oil small circulation assembly, cooling assembly and lubricating oil large circulation assembly in combination, the low-temperature lubricating oil and high-temperature lubricating oil no longer share the same circulation pipeline for circulation. That is, the low-temperature lubricating oil no longer passes through the cooler, and can directly enter the bipolar compressor host after being filtered by the oil-gas separator. This greatly shortens the circulation path of the low-temperature lubricating oil, which greatly shortens the time required for the low-temperature lubricating oil to circulate to the compressor host, and is beneficial to the start-up speed of the compressor host. Attached Figure Description

[0016] Figure 1 The system schematic diagram provided for this utility model;

[0017] Figure 2 This is a schematic diagram of the structure of the oil-gas separator provided by this utility model.

[0018] In the diagram: 1. Main motor; 2. Controller; 3. Frequency converter; 4. Coupling; 5. Dual-stage compressor main unit; 6. Intake valve; 7. Air filter; 8. Air inlet; 9. Oil-gas separator; 91. Oil-gas mixture inlet; 92. Lubricating oil outlet; 93. Exhaust port; 94. Oil return port; 10. First lubricating oil pipe; 11. Temperature control valve; 12. Second lubricating oil pipe; 13. Lubricating oil filter; 14. Safety valve; 15. Fan; 16. Cooler; 17. Exhaust pipe; 18. Compressed air outlet; 19. Third lubricating oil pipe; 20. Fourth lubricating oil pipe; 21. Oil return pipe. Detailed Implementation

[0019] The preferred embodiments of the present invention will be described below with reference to the accompanying drawings. It should be understood that the preferred embodiments described herein are for illustration and explanation only and are not intended to limit the present invention.

[0020] Please refer to the appendix. Figures 1-2 This utility model provides a PID control system for an oil-injected screw air compressor, including a main motor 1 and a controller 2. The controller 2 is signal-connected to a frequency converter 3, and the frequency converter 3 is electrically connected to the main motor 1. The output shaft of the main motor 1 is fixed to a dual-stage compressor host 5 through a coupling 4. That is, when the main motor 1 is running, it can drive the dual-stage compressor host 5 to run through the coupling 4, thereby compressing air. Its principle and structure are well known to those skilled in the art and will not be described in detail. The dual-stage compressor host 5 is connected to an air filter assembly and an oil-gas separation assembly through pipes. The oil-gas separation assembly is connected to a lubricating oil small circulation assembly and a cooling assembly through pipes. A lubricating oil large circulation assembly is set between the lubricating oil small circulation assembly and the cooling assembly. The cooling assembly is electrically connected to the controller 2.

[0021] The air filtration assembly includes an intake valve 6, a dual-stage compressor 5 connected to the intake valve 6, an air filter 7 connected to the intake valve 6, and an air inlet 8 connected to the air filter 7. Specifically, under the filtering action of the air filter 7, the filtered air can enter the dual-stage compressor 5 for compression.

[0022] The oil-gas separation assembly includes an oil-gas separator 9. It should be noted that an oil separator core (not marked in the figure) is provided on the upper side inside the oil-gas separator 9 for oil-gas separation. An oil-gas mixture inlet 91 is fixedly connected to the middle of the oil-gas separator 9. The bipolar compressor host 5 is connected to the oil-gas mixture inlet 91 by a pipeline. A lubricating oil outlet 92 is also fixedly connected to the middle of the oil-gas separator 9. An exhaust port 93 and an oil return port 94 are also fixedly connected to the top of the oil-gas separator 9. A safety valve 14 is connected to the top of the oil-gas separator 9 by a pipeline. Specifically, the lubricating oil and compressed air mixture during the operation of the bipolar compressor host 5 is transmitted to the oil-gas separator 9 for separation.

[0023] The lubricating oil small circulation assembly includes a first lubricating oil pipe 10, one end of which is fixedly connected to the lubricating oil outlet 92, and the other end of which is fixedly connected to a temperature control valve 11. It should be noted that the temperature control valve 11 is preferably set to 71°C. When the lubricating oil temperature is below 71°C, the temperature control valve 11 is in the closed state, and when the lubricating oil temperature is above 71°C, the temperature control valve 11 is in the open state. The temperature control valve 11 is fixedly connected to a second lubricating oil pipe 12, and the second lubricating oil pipe 12 is fixedly connected to a lubricating oil filter 13. The lubricating oil filter 13 is connected to the bipolar compressor host 5. Specifically, the low-temperature lubricating oil required when the bipolar compressor host 5 starts can be transported through the first lubricating oil pipe 10 and the second lubricating oil pipe 12, and after being filtered by the lubricating oil filter 13, it is directly circulated into the bipolar compressor host 5.

[0024] The cooling assembly includes a fan 15 and a cooler 16. The fan 15 is electrically connected to the controller 2. The exhaust port 93 is fixedly connected to the exhaust pipe 17. The exhaust pipe 17 is connected to the input end of the cooler 16. The output end of the cooler 16 is fixedly connected to the compressed air outlet 18. Specifically, when the fan 15 is running, it can generate cold air to cool the cooler 16. This allows the high-temperature compressor, after being separated by the oil-gas separator 9, to be effectively cooled when it enters the cooler 16 through the exhaust pipe 17 and then discharged through the compressed air outlet 18 to the equipment that needs compressed air.

[0025] The lubricating oil circulation assembly includes a third lubricating oil pipe 19. One end of the third lubricating oil pipe 19 is fixedly connected to the temperature control valve 11, and the other end of the third lubricating oil pipe 19 is fixedly connected to the cooler 16. The cooler 16 is also fixedly connected to a fourth lubricating oil pipe 20. The fourth lubricating oil pipe 20 is fixedly connected to the body of the second lubricating oil pipe 12. The return oil port 94 is fixedly connected to the return oil pipe 21. The body of the return oil pipe 21 is fixedly equipped with a one-way valve 22, and the return oil pipe 21 is connected to the pipeline of the dual-stage compressor host 5. Specifically, when the temperature of the lubricating oil of the dual-stage compressor host 5 exceeds 71°C after running for a period of time, the temperature control valve 11 opens. At this time, the high-temperature lubricating oil transported through the first lubricating oil pipe 10 and the second lubricating oil pipe 12 can enter the cooler 16 through the third lubricating oil pipe 19 for cooling, and then enter the lubricating oil filter 13 through the fourth lubricating oil pipe 20 and the second lubricating oil pipe 12 for filtration, and then circulate back into the dual-stage compressor host 5.

[0026] In summary, this control system allows low-temperature lubricating oil and high-temperature lubricating oil to no longer share the same circulation pipeline for circulation. That is, the low-temperature lubricating oil no longer passes through the cooler 16, but can directly enter the bipolar compressor host 5 after being filtered by the oil-gas separator 9. This greatly shortens the circulation path of the low-temperature lubricating oil, which can significantly reduce the time required for the low-temperature lubricating oil to circulate to the compressor host, thus benefiting the start-up speed of the compressor host.

[0027] The usage process of this utility model is as follows: When the dual-stage compressor host 5 starts, the required low-temperature lubricating oil can be transported through the first lubricating oil pipe 10 and the second lubricating oil pipe 12, and after being filtered by the lubricating oil filter 13, it is directly circulated into the dual-stage compressor host 5. Then, the main motor 1 runs and drives the dual-stage compressor host 5 through the coupling 4, so that the air is filtered by the air filter 7 and enters the dual-stage compressor host 5 for compression. The mixture of lubricating oil and compressed air during the operation of the dual-stage compressor host 5 is transferred to the oil-air separator 9 for separation. When the dual-stage compressor host 5 has been running for a period of time, its lubricating oil temperature exceeds 71°C, and the temperature control valve 11 opens. At this time, the lubricating oil flows through the first lubricating oil pipe 10... The high-temperature lubricating oil transported by the second lubricating oil pipe 12 can enter the cooler 16 through the third lubricating oil pipe 19 for cooling, and then enter the lubricating oil filter 13 through the fourth lubricating oil pipe 20 and the second lubricating oil pipe 12 for filtration, and then circulate back into the dual-stage compressor host 5. Therefore, this control system can make the low-temperature lubricating oil and the high-temperature lubricating oil no longer share the same circulation pipe for circulation. That is, the low-temperature lubricating oil no longer passes through the cooler 16, and can directly enter the dual-stage compressor host 5 after being filtered by the oil-gas separator 9, thereby greatly shortening the circulation path of the low-temperature lubricating oil, which can greatly shorten the time required for the low-temperature lubricating oil to circulate to the compressor host, which is beneficial to the start-up speed of the compressor host.

[0028] Meanwhile, when the high-temperature compressor, after being separated by the oil-gas separator 9, enters the cooler 16 through the exhaust pipe 17, it can be effectively cooled and then discharged to the equipment that needs compressed air through the compressed air outlet 18.

[0029] The above description is merely a preferred embodiment of this utility model. Any person skilled in the art can modify this utility model or modify it into an equivalent technical solution using the technical solution described above. Therefore, any simple modifications or equivalent substitutions made based on the technical solution of this utility model are within the scope of protection claimed by this utility model.

Claims

1. A PID control system for an oil-injected screw air compressor, comprising a main motor (1) and a controller (2), wherein the controller (2) is signal-connected to a frequency converter (3), the frequency converter (3) is electrically connected to the main motor (1), and a bipolar compressor main unit (5) is fixed to the output shaft of the main motor (1) via a coupling (4), characterized in that: The dual-stage compressor host (5) is connected to an air filter assembly and an oil-gas separation assembly via pipelines. The oil-gas separation assembly is connected to a lubricating oil small circulation assembly and a cooling assembly via pipelines. A lubricating oil large circulation assembly is provided between the lubricating oil small circulation assembly and the cooling assembly. The cooling assembly is electrically connected to a controller (2).

2. The PID control system for an oil-injected screw air compressor according to claim 1, characterized in that: The air filtration assembly includes an intake valve (6), the dual-stage compressor (5) is connected to the intake valve (6) via a pipe, the intake valve (6) is connected to an air filter (7) via a pipe, and the air filter (7) is connected to an air inlet (8) via a pipe.

3. The PID control system for an oil-injected screw air compressor according to claim 1, characterized in that: The oil-gas separation assembly includes an oil-gas separator (9), an oil-gas mixture inlet (91) is fixedly connected to the middle of the oil-gas separator (9), the dual-stage compressor host (5) is pipe-connected to the oil-gas mixture inlet (91), a lubricating oil outlet (92) is also fixedly connected to the middle of the oil-gas separator (9), and an exhaust port (93) and an oil return port (94) are also fixedly connected to the top of the oil-gas separator (9).

4. The PID control system for an oil-injected screw air compressor according to claim 3, characterized in that: The lubricating oil small circulation assembly includes a first lubricating oil pipe (10), one end of which is fixedly connected to the lubricating oil outlet (92), and the other end of which is fixedly connected to a temperature control valve (11). The temperature control valve (11) is fixedly connected to a second lubricating oil pipe (12), and the second lubricating oil pipe (12) is fixedly connected to a lubricating oil filter (13). The lubricating oil filter (13) is connected to the bipolar compressor host (5) via a pipeline.

5. The PID control system for an oil-injected screw air compressor according to claim 3, characterized in that: The top pipe of the oil-gas separator (9) is connected to a safety valve (14).

6. The PID control system for an oil-injected screw air compressor according to claim 4, characterized in that: The cooling assembly includes a fan (15) and a cooler (16), wherein the fan (15) is electrically connected to a controller (2).

7. A PID control system for an oil-injected screw air compressor according to claim 6, characterized in that: The exhaust port (93) is fixedly connected to an exhaust pipe (17), the exhaust pipe (17) is connected to the input end of the cooler (16), and the output end of the cooler (16) is fixedly connected to a compressed air outlet (18).

8. The PID control system for an oil-injected screw air compressor according to claim 6, characterized in that: The lubricating oil circulation assembly includes a third lubricating oil pipe (19), one end of which is fixedly connected to a temperature control valve (11), and the other end of which is fixedly connected to a cooler (16). The cooler (16) is also fixedly connected to a fourth lubricating oil pipe (20), which is fixedly connected to the body of the second lubricating oil pipe (12).

9. A PID control system for an oil-injected screw air compressor according to claim 3, characterized in that: The return port (94) is fixedly connected to the return pipe (21), and the return pipe (21) is fixed with a one-way valve (22), and the return pipe (21) is connected to the dual-stage compressor host (5).

Images