Diesel power screw machine air inlet control system and control method thereof

Abstract

The invention discloses an air inlet control system of a diesel power screw machine and a control method of the air inlet control system. The air inlet control system comprises a double-acting turning plate type normally-closed integrated air inlet valve, an electromagnetic valve, a direct proportional valve and a pressure reducing valve. The air filter is connected with the air inlet end of the turning plate type air inlet valve, the electromagnetic valve, the direct proportion valve and the pressure reducing valve are connected with the double-acting turning plate type normally-closed integrated air inlet valve, and the exhaust end of the double-acting turning plate type normally-closed integrated air inlet valve is connected with the screw main machine. According to the diesel power screw machine air inlet control system and the control method thereof, the double-acting turning plate type normally-closed integrated air inlet valve is adopted, the unloading emptying function and the shutdown emptying function are integrated, the state of the air inlet valve is controlled through the pressure reducing valve, the direct proportion valve and the electromagnetic valve, and the requirements for light starting load, fast response during unloading and stable pressure can be met.

Description

Technical Field

[0001] The invention belongs to the technical field of screw compressors and relates to a screw machine, and in particular to an air intake control system and a control method thereof for a diesel powered screw machine. Background Art

[0002] There are two schemes for the existing diesel-powered screw compressor air intake control system: the first scheme air intake control system is composed of piston-type normally open air intake valve, proportional valve, solenoid valve, vent valve and other parts; when the unit is started, the air intake valve is fully opened, and the large air intake volume is started, and the starting load is large, causing difficulty in starting, which is more difficult in high altitude and low temperature environments.

[0003] The air intake control system of the second scheme is mainly composed of parts such as a flap-type normally closed air intake valve, a proportional valve, a solenoid valve, and a vent valve; the unit can be started normally in this scheme, but a pressure surge problem will occur when the unit is unloaded, causing the safety valve to open, resulting in energy waste.

[0004] In view of this, there is an urgent need to design a new diesel-powered screw compressor air intake control method to overcome at least some of the above-mentioned defects of the existing air intake control method. Summary of the invention

[0005] The present invention provides a diesel powered screw compressor air intake control system and a control method thereof, which can achieve the requirements of light starting load, fast response during unloading and stable pressure.

[0006] To solve the above technical problem, according to one aspect of the present invention, the following technical solution is adopted:

[0007] An air intake control system for a diesel powered screw compressor, the air intake control system comprising: an air intake valve, a solenoid valve, a proportional valve and a pressure reducing valve;

[0008] The intake valve comprises a cylinder and a throttle hole, wherein the cylinder is a double-acting cylinder; the cylinder is provided with a cylinder opening chamber and a cylinder closing chamber; the cylinder opening chamber is provided with a cylinder opening interface, and the cylinder closing chamber is provided with a cylinder closing interface;

[0009] The inlet of the pressure reducing valve is connected to the oil-gas separation tank, and the outlet of the pressure reducing valve is connected to the cylinder opening interface of the air intake valve; the inlet of the positive proportional valve is connected to the oil-gas separation tank, and the outlet of the positive proportional valve is connected to the cylinder closing interface of the air intake valve;

[0010] The inlet of the solenoid valve is connected to the oil-gas separation tank, and the outlet of the solenoid valve is connected to the cylinder closing interface of the intake valve; the exhaust end of the intake valve is connected to the main engine of the screw machine;

[0011] When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation.

[0012] When the screw compressor is loaded and running, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the cylinder closing chamber of the intake valve is closed from the oil-gas separation tank. The pressure in the cylinder closing chamber is reduced, and there is a pressure difference between the cylinder opening chamber and the cylinder closing chamber. The cylinder moves, and the intake valve opens to achieve full-flow intake.

[0013] When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit.

[0014] When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions;

[0015] After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

[0016] As an embodiment of the present invention, the intake valve is a double-acting flap type normally closed integrated intake valve; the functional parts included in the intake valve include a double-acting cylinder, which is equipped with a throttle flap, an unloading vent valve, a vent flow regulating valve, a shutdown vent valve and a shutdown check valve.

[0017] As an embodiment of the present invention, the air intake valve has the functions of air intake throttling, unloading and venting, venting flow adjustment, unloading and air replenishment, shutdown and venting, and shutdown check. The air intake valve is in a normally closed state under normal circumstances.

[0018] According to another aspect of the present invention, the following technical solution is adopted: an air intake control method of the above-mentioned diesel-powered screw compressor air intake control system, the air intake control method comprising:

[0019] When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation.

[0020] When the screw compressor is running under load, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the closing chamber of the cylinder of the intake valve is closed from the oil-gas separation tank. The pressure in the closing chamber of the cylinder is reduced, and there is a pressure difference between the two chambers of the cylinder. The cylinder moves, and the intake valve opens to achieve full-flow intake.

[0021] When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit.

[0022] When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions;

[0023] After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

[0024] The air intake system of the present invention adopts a double-acting normally closed integrated air intake valve, which integrates the functions of air intake throttling, unloading and venting, unloading and air replenishment, and shutdown and venting. Through the signal control of the pressure reducing valve, the proportional valve, and the solenoid valve, it realizes low-load starting, rapid response of the exhaust pressure during loading, more stable exhaust pressure control by capacity adjustment, unloading and air replenishment, venting flow adjustment, low-load shutdown and other functions.

[0025] The beneficial effects of the present invention are as follows: the diesel-powered screw compressor air intake control system and control method proposed in the present invention adopt a double-acting flap-type normally closed integrated air intake valve, which integrates the unloading venting and shutdown venting functions, and controls the state of the air intake valve through a pressure reducing valve, a proportional valve, and a solenoid valve, so as to achieve the requirements of light starting load, fast response during unloading, and stable pressure. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The figure is a schematic diagram of the composition of the air intake control system of a diesel-powered screw compressor in one embodiment of the present invention.

[0027] Figure 2 It is a structural schematic diagram of a double-acting normally closed integrated intake valve in one embodiment of the present invention.

[0028] Figure 3 It is a structural schematic diagram of a double-acting normally closed integrated intake valve in one embodiment of the present invention.

[0029] Figure 4 It is a structural schematic diagram of a double-acting normally closed integrated intake valve in one embodiment of the present invention.

[0030] Figure 5 It is a structural schematic diagram of a double-acting normally closed integrated intake valve in one embodiment of the present invention.

[0031] Figure 6 It is a structural schematic diagram of a double-acting normally closed integrated intake valve in one embodiment of the present invention. DETAILED DESCRIPTION

[0032] The preferred embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0033] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples. However, it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention, rather than limiting the claims of the present invention.

[0034] The description in this section is only for several typical embodiments, and the present invention is not limited to the scope of the embodiments. The same or similar prior art means and some technical features in the embodiments are mutually replaced within the scope of the present invention.

[0035] The description of the steps in each embodiment in the specification is only for the convenience of explanation, and the implementation method of the present application is not limited by the order of implementation of the steps.

[0036] The term “connection” in the specification includes both direct connection and indirect connection.

[0037] The present invention discloses an air intake control system for a diesel powered screw compressor. Figure 1 This is a schematic diagram of the composition of the diesel powered screw compressor air intake control system in one embodiment of the present invention; please refer to Figure 1 The diesel-powered screw compressor air intake control system includes: an air intake valve 3, a solenoid valve 18, a proportional valve 21 and a pressure reducing valve 22.

[0038] Figures 2 to 6This is a schematic diagram of the structure of a double-acting normally closed integrated intake valve in one embodiment of the present invention; please refer to Figures 2 to 6 The intake valve 3 includes a cylinder 34 and a throttle hole. The cylinder is a double-acting cylinder. The cylinder is provided with a cylinder opening chamber and a cylinder closing chamber. The cylinder opening chamber is provided with a cylinder opening interface, and the cylinder closing chamber is provided with a cylinder closing interface.

[0039] The inlet of the pressure reducing valve 22 is connected to the oil-gas separation tank 7, and the outlet of the pressure reducing valve 22 is connected to the cylinder opening interface of the intake valve 3; a throttle valve 23 may be provided in the connecting pipeline between the pressure reducing valve 22 and the intake valve 3. The inlet of the positive proportional valve 21 is connected to the oil-gas separation tank 7, and the outlet of the positive proportional valve 21 is connected to the cylinder closing interface of the intake valve. The inlet of the solenoid valve 18 is connected to the oil-gas separation tank 7, and the outlet of the solenoid valve 18 is connected to the cylinder closing interface of the intake valve 3; the exhaust end of the intake valve 3 is connected to the main engine 5 of the screw machine.

[0040] When the screw machine starts running, a small amount of air enters the screw machine main unit 5 through the throttle hole of the intake valve 3 for compression, the air pressure in the oil-gas separation tank 7 slowly increases, and the compressed air is delivered to the cylinder opening chamber of the intake valve 3 through the pressure reducing valve 22. At the same time, the compressed air is delivered to the cylinder closing chamber of the intake valve 3 through the solenoid valve 18. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve 3 is in a closed state, and the screw machine (screw machine main unit 5) is in low-load starting operation.

[0041] When the screw machine is loaded and running, the exhaust pressure is lower than the set pressure of the proportional valve 21, the solenoid valve 18 is energized, closing the compressed air from the oil-gas separation tank 7 to the cylinder closing chamber of the intake valve 3, the pressure in the cylinder closing chamber is reduced, and there is a pressure difference between the two chambers of the cylinder (the cylinder opening chamber and the cylinder closing chamber), the cylinder is actuated, and the intake valve 3 is opened to achieve full-flow intake.

[0042] When the screw machine is running under capacity control, the exhaust pressure is equal to the set pressure of the positive proportional valve. When the inlet pressure of the positive proportional valve 21 reaches the set pressure, the compressed air flows out through the positive proportional valve 21, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve 3 is gradually closed, and the output pressure of the positive proportional valve 21 increases. Until the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve 3 is completely closed. At the same time, the compressed air output by the positive proportional valve 21 enters the control chamber of the unloading vent valve, opening the vent valve to intake, vent and replenish air, thereby achieving stable exhaust pressure of the unit.

[0043] When the screw machine is unloading, when the pressure reaches the set pressure (which can be set by the PLC controller or by manually sending instructions), the solenoid valve 18 loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve 18, closing the air intake valve to achieve the unloading and venting functions.

[0044] After the screw machine is shut down, compressed air enters the air inlet chamber of the screw machine main engine 5, the shutdown vent valve control chamber is connected to the air inlet chamber of the screw machine main engine 5, compressed air enters the shutdown vent valve control chamber, the shutdown vent valve is opened, and the shutdown venting is performed.

[0045] See also Figures 2 to 6 In one embodiment of the present invention, the intake valve 3 is a double-acting flap type normally closed integrated intake valve; the functional parts included in the intake valve include a double-acting cylinder, provided with a throttle flap 36, an unloading vent valve 32, a vent flow regulating valve 31, a shutdown vent valve 33 and a shutdown check valve 35. The intake valve 3 has the functions of intake throttling, unloading venting, vent flow regulating, unloading air supply, shutdown venting, and shutdown check, and the intake valve is in a normally closed state. The intake end of the intake valve 3 is connected to an air filter 1, and the air filter 1 is connected to an air filter pressure difference transmitter 2.

[0046] The present invention also discloses a diesel-powered screw compression device, which includes a screw machine main unit 5, an oil-gas separation tank 7 and a screw machine air intake control system, wherein the screw machine air intake control system is respectively connected to the screw machine main unit 5 and the oil-gas separation tank 7.

[0047] The screw compression device may further include a diesel engine 4, which is connected to the screw main engine 5 and can provide power for the screw main engine 5. Of course, the screw main engine 5 can also be driven by other driving mechanisms.

[0048] In one embodiment of the present invention, the screw compression device further includes an oil filter 12, an oil return check valve 20, an oil-gas separation core 8, a temperature control valve 10 and an oil cooler 11. The first end of the oil filter 12 is connected to the lubricating oil input end of the screw main engine 5, and the lubricating oil output end of the screw main engine 5 is connected to the oil-gas separation core 8 through the oil return check valve 20; the oil-gas separation core 8 is connected to the oil-gas separation tank 7. The lubricating oil separated from the oil-gas separation tank 7 is transported to the temperature control valve 10; the first output end of the temperature control valve 10 is connected to the oil filter 12 through the oil cooler 11, and the second output end of the temperature control valve 10 is directly connected to the oil filter 12. The oil filter 12 can be connected to the oil filter pressure difference transmitter 13, and the oil filter pressure difference can be sent to a remote end.

[0049] The screw compression device may further include a minimum pressure valve 15 and an aftercooler 16; the oil-gas separation core 8 is connected to the minimum pressure valve 15, and the minimum pressure valve 15 is connected to the aftercooler 16. The gas separated by the oil-gas separation tank 7 is output in sequence through the oil-gas separation core 8, the minimum pressure valve 15, and the aftercooler 16; an exhaust pressure sensor 17 may be provided at the exhaust end, and the exhaust pressure sensor 17 is used to sense the exhaust pressure.

[0050] In addition, the screw machine main unit 5 is also connected to an oil seal oil return check valve 14; a temperature sensor 6 can be provided in the pipeline between the screw machine main unit 5 and the oil-liquid separator 7. The oil-gas separation tank 7 can be provided with a safety valve 9 and a sewage ball valve 19.

[0051] The present invention further discloses an air intake control method of the above-mentioned diesel-powered screw compressor air intake control system, and the air intake control method comprises:

[0052] When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation.

[0053] When the screw compressor is running under load, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the closing chamber of the cylinder of the intake valve is closed from the oil-gas separation tank. The pressure in the closing chamber of the cylinder is reduced, and there is a pressure difference between the two chambers of the cylinder. The cylinder moves, and the intake valve opens to achieve full-flow intake.

[0054] When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit.

[0055] When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions;

[0056] After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

[0057] The present invention also discloses an air intake control method for the above diesel powered screw compressor, the air intake control method comprising:

[0058] When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation.

[0059] When the screw compressor is running under load, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the closing chamber of the cylinder of the intake valve is closed from the oil-gas separation tank. The pressure in the closing chamber of the cylinder is reduced, and there is a pressure difference between the two chambers of the cylinder. The cylinder moves, and the intake valve opens to achieve full-flow intake.

[0060] When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit.

[0061] When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions;

[0062] After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

[0063] In one embodiment of the present invention, the present invention adopts a double-acting normally closed integrated intake valve, which integrates the functions of intake throttling, unloading and venting, unloading and air replenishment, and shutdown and venting. Through the signal control of the pressure reducing valve, the proportional valve, and the solenoid valve, the functions of low-load starting, rapid response of exhaust pressure during loading, more stable exhaust pressure control by capacity adjustment, unloading and air replenishment, venting flow adjustment, and low-load shutdown are realized.

[0064] In summary, the diesel-powered screw compressor air intake control system and control method proposed in the present invention adopts a double-acting flap-type normally closed integrated intake valve, which integrates the unloading and venting functions and the shutdown and venting functions, and controls the state of the intake valve through a pressure reducing valve, a proportional valve, and a solenoid valve, so as to achieve the requirements of light starting load, fast response during unloading, and stable pressure.

[0065] It should be noted that the present application can be implemented in software and / or a combination of software and hardware; for example, it can be implemented using an application-specific integrated circuit (ASIC), a general-purpose computer, or any other similar hardware device. In some embodiments, the software program of the present application can be executed by a processor to implement the above steps or functions. Similarly, the software program of the present application (including related data structures) can be stored in a computer-readable recording medium; for example, a RAM memory, a magnetic or optical drive or a floppy disk and the like. In addition, some steps or functions of the present application can be implemented in hardware; for example, as a circuit that cooperates with a processor to perform various steps or functions.

[0066] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0067] The description and application of the present invention here are illustrative, and it is not intended to limit the scope of the present invention to the above-mentioned embodiments. The effects or advantages involved in the embodiments may not be embodied in the embodiments due to interference from various factors, and the description of the effects or advantages is not used to limit the embodiments. The deformation and change of the embodiments disclosed here are possible, and the replacement of the embodiments and the various equivalent parts are well known to those of ordinary skill in the art. It should be clear to those skilled in the art that the present invention can be implemented in other forms, structures, arrangements, proportions, and with other components, materials and parts without departing from the spirit or essential features of the present invention. Other deformations and changes can be made to the embodiments disclosed here without departing from the scope and spirit of the present invention.

Claims

1. A diesel powered screw compressor air intake control system, characterized in that: The air intake control system includes: an air intake valve, a solenoid valve, a proportional valve and a pressure reducing valve; The intake valve comprises a cylinder and a throttle hole, wherein the cylinder is a double-acting cylinder; the cylinder is provided with a cylinder opening chamber and a cylinder closing chamber; the cylinder opening chamber is provided with a cylinder opening interface, and the cylinder closing chamber is provided with a cylinder closing interface; The inlet of the pressure reducing valve is connected to the oil-gas separation tank, and the outlet of the pressure reducing valve is connected to the cylinder opening interface of the air intake valve; the inlet of the positive proportional valve is connected to the oil-gas separation tank, and the outlet of the positive proportional valve is connected to the cylinder closing interface of the air intake valve; The inlet of the solenoid valve is connected to the oil-gas separation tank, and the outlet of the solenoid valve is connected to the cylinder closing interface of the intake valve; the exhaust end of the intake valve is connected to the main engine of the screw machine; When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation. When the screw compressor is loaded and running, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the cylinder closing chamber of the intake valve is closed from the oil-gas separation tank. The pressure in the cylinder closing chamber is reduced, and there is a pressure difference between the cylinder opening chamber and the cylinder closing chamber. The cylinder moves, and the intake valve opens to achieve full-flow intake. When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit. When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions; After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

2. The diesel powered screw compressor air intake control system according to claim 1, characterized in that: The air intake valve is a double-acting flap-type normally closed integrated air intake valve; the functional parts included in the air intake valve include a double-acting cylinder, which is provided with a throttle flap, an unloading vent valve, a vent flow regulating valve, a shutdown vent valve and a shutdown check valve.

3. The diesel powered screw compressor air intake control system according to claim 1, characterized in that: The air intake valve has the functions of air intake throttling, unloading and venting, venting flow rate adjustment, unloading and air replenishment, shutdown and venting, and shutdown check. The air intake valve is in a normally closed state under normal conditions.

4. An air intake control method for a diesel powered screw compressor air intake control system according to any one of claims 1 to 3, characterized in that: The air intake control method comprises: When the screw compressor starts running, a small amount of air enters the main engine of the screw compressor through the throttle hole of the intake valve for compression. The air pressure in the oil-gas separation tank gradually increases, and the compressed air is transported to the cylinder opening chamber of the intake valve through the pressure reducing valve. At the same time, the compressed air is transported to the cylinder closing chamber of the intake valve through the solenoid valve. The gas pressures in the cylinder opening chamber and the cylinder closing chamber are the same, the intake valve is in a closed state, and the screw compressor is in a low-load starting operation. When the screw compressor is running under load, the exhaust pressure is lower than the set pressure of the proportional valve, the solenoid valve is energized, and the compressed air in the closing chamber of the cylinder of the intake valve is closed from the oil-gas separation tank. The pressure in the closing chamber of the cylinder is reduced, and there is a pressure difference between the two chambers of the cylinder. The cylinder moves, and the intake valve opens to achieve full-flow intake. When the screw compressor is running under capacity control, the exhaust pressure is equal to the set pressure of the proportional valve. When the inlet pressure of the proportional valve reaches the set pressure, the compressed air flows out through the proportional valve, and the pressure in the cylinder closing chamber begins to gradually increase. The cylinder begins to retract, causing the flap to rotate and close the inlet of the intake valve to achieve flow regulation. As the external gas consumption decreases, the intake valve gradually closes, and the output pressure of the proportional valve increases. When the pressure in the cylinder closing chamber increases to a level greater than the pressure in the opening chamber, the intake valve is completely closed. At the same time, the compressed air output by the proportional valve enters the control chamber of the unloading vent valve, and the vent valve is opened to intake, vent and replenish air, achieving stable exhaust pressure of the unit. When the screw compressor is unloading, when the pressure reaches the set pressure, the solenoid valve loses power, and the compressed air enters the cylinder closing chamber through the solenoid valve, closing the air inlet valve to achieve the unloading and venting functions; After the screw machine is shut down, compressed air enters the air inlet chamber of the main engine of the screw machine. The control chamber of the shutdown vent valve is connected to the air inlet chamber of the main engine of the screw machine. Compressed air enters the control chamber of the shutdown vent valve, and the shutdown vent valve is opened to perform shutdown venting.

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