Screw machine load valve unloading maintenance control system and maintenance method thereof

Abstract

The present application belongs to the technical field of valve maintenance, and particularly relates to a screw machine load valve unloading maintenance control system and a maintenance method thereof, which comprises two parallelly arranged load valves and a pressure container connected with the two load valves; the pressure container is connected with a solenoid valve air supply hose; an unloading solenoid valve is arranged on the solenoid valve air supply hose; the unloading solenoid valve is connected with the first load valve through a first control loop; the unloading solenoid valve is connected with the second load valve through a second control loop; the unloading solenoid valve is connected with a temperature regulating bypass valve through a third control loop; a first air cut-off ball valve is arranged between the unloading solenoid valve and the pressure container; a second air cut-off ball valve is arranged between the first load valve and the pressure container; and a third air cut-off ball valve is arranged between the second load valve and the pressure container. Through installation of the three air cut-off ball valves, the complicated and tedious fault handling of the screw machine cannot be unloaded is simplified, the work load is reduced, and the fault can be handled faster.

Description

Technical Field

[0001] This invention belongs to the field of valve maintenance technology, specifically relating to a screw compressor load valve unloading maintenance control system and its maintenance method. Background Technology

[0002] After a period of long-term operation, screw compressors may malfunction. Eventually, when the compressor reaches its set unloading limit, it fails to unload, and the unloading solenoid valve continuously vents air during unloading. Normally, during unloading, the solenoid valve vents air instantly, causing the compressor's load valve to close under spring pressure. The fact that compressed air is not completely vented during unloading indicates that compressed air has entered the system, causing the load valve to open and preventing unloading. Therefore, it is necessary to disassemble, inspect, and reinstall each valve on the load valve connection line to determine the specific cause of the malfunction. This process is tedious, time-consuming, and labor-intensive. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the purpose of this invention is to provide a screw compressor load valve unloading and maintenance control system and its maintenance method, which can quickly determine the status of each valve on the load valve connection line through a simple method, simplify the maintenance steps, and improve maintenance efficiency.

[0004] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a screw compressor load valve unloading maintenance control system, comprising two load valves connected in parallel and a pressure vessel connected to the two load valves; the pressure vessel is connected to a solenoid valve air supply hose, and an loading / unloading solenoid valve is installed on the solenoid valve air supply hose. The loading / unloading solenoid valve is connected to the first load valve through a first control circuit, connected to the second load valve through a second control circuit, and connected to a temperature regulating bypass valve through a third control circuit; a first air-stop valve is installed between the loading / unloading solenoid valve and the pressure vessel, a second air-stop valve is installed between the first load valve and the pressure vessel, and a third air-stop valve is installed between the second load valve and the pressure vessel.

[0005] Further, the first control loop includes a first load valve control hose and a first load valve exhaust hose, the solenoid valve supply hose is connected to the first load valve through the first load valve control hose, and the pressure vessel is connected to the first load valve through the first load valve exhaust hose; the second control loop includes a second load valve control hose and a second load valve exhaust hose, the solenoid valve supply hose is connected to the second load valve through the second load valve control hose, and the pressure vessel is connected to the second load valve through the second load valve exhaust hose; the third control loop includes a temperature regulating bypass valve control hose and a temperature regulating bypass valve actuation hose, the solenoid valve supply hose is connected to the temperature regulating bypass valve through the temperature regulating bypass valve control hose, and the pressure vessel is connected to the temperature regulating bypass valve through the temperature regulating bypass valve actuation hose.

[0006] Furthermore, the first air-stop valve is installed on the solenoid valve supply hose, the second air-stop valve is installed on the first load valve exhaust hose, and the third air-stop valve is installed on the second load valve exhaust hose.

[0007] Furthermore, the second air-stop valve is mounted on the first load valve, the first load valve contains a first piston valve, and the second air-stop valve is connected to the air inlet pipe of the first piston valve; the third air-stop valve is mounted on the second load valve, the second load valve contains a second piston valve, and the third air-stop valve is connected to the air inlet pipe of the second piston valve.

[0008] Furthermore, the first load valve control hose is connected to the air intake control interface of the first load valve, and the first load valve exhaust hose is connected to the exhaust interface of the first load valve; the second load valve control hose is connected to the air intake control interface of the second load valve, and the second load valve exhaust hose is connected to the exhaust interface of the second load valve.

[0009] Furthermore, the loading and unloading solenoid valve is connected to the control system via a power supply circuit.

[0010] Furthermore, the pressure vessel is a gas storage tank or an oil-gas separator.

[0011] The maintenance method for the screw compressor load valve unloading and maintenance control system includes the following steps:

[0012] Step 1: During normal startup, the loading and unloading solenoid valves of the screw compressor are in the open state when loading and in the closed state when unloading; the temperature regulating bypass valve is in different positions according to the oil temperature and loading and unloading status; under normal circumstances, the first cut-off valve, the second cut-off valve, and the third cut-off valve are in the open position.

[0013] Step 2: If the loading / unloading solenoid valve does not vent during screw compressor unloading operation, check the power supply circuit of the loading / unloading solenoid valve. If the wiring terminal has 24VAC power, then the control system is faulty; if the loading / unloading solenoid valve vents (venting time is about 10 seconds), then the control system is normal.

[0014] Step 3: The loading / unloading solenoid valve continues to vent air. Close the first shut-off valve. If the loading / unloading solenoid valve does not vent air, it is faulty. If the loading / unloading solenoid valve vents air (venting time is about 10 seconds), it is normal.

[0015] Step 4: Open the first shut-off valve, close the second shut-off valve, and open the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the first load valve is faulty; if the loading / unloading solenoid valve vents air, the first load valve is normal.

[0016] Step 5: Open the first and second shut-off valves, and close the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the second load valve is faulty; if the loading / unloading solenoid valve vents air, the second load valve is normal.

[0017] Step Six: Close the first, second, and third shut-off valves. If the loading / unloading solenoid valve does not vent, it means that no gas is entering the solenoid valve control air path of the temperature regulation bypass valve. If the loading / unloading solenoid valve vents, it means that gas is entering the solenoid valve control air path of the temperature regulation bypass valve, and the sealing ring inside the temperature regulation bypass valve is damaged.

[0018] Furthermore, in step three, the power supply circuit of the loading and unloading solenoid valve is tested using a multimeter.

[0019] Furthermore, in step four, the fault of the first load valve is internal leakage of the first piston valve within the first load valve; in step five, the fault of the second load valve is internal leakage of the second piston valve within the second load valve.

[0020] The beneficial effects of this invention are: by installing three air-stop valves, the complex and cumbersome troubleshooting of screw compressors failing to unload is simplified, the workload is reduced, and the fault can be resolved more quickly. Attached Figure Description

[0021] Figure 1 This is a control diagram for the load valve of a screw compressor.

[0022] In the diagram: 1. Pressure vessel; 2. Loading / unloading solenoid valve; 3. Temperature regulating bypass valve; 4. First load valve; 5. First piston valve; 6. Second load valve; 7. Second piston valve; 8. First shut-off valve; 9. Second shut-off valve; 10. Third shut-off valve; 11. Control system; 12. Solenoid valve supply hose; 13. First load valve control hose; 14. First load valve exhaust hose; 15. Second load valve control hose; 16. Second load valve exhaust hose; 17. Temperature regulating bypass valve control hose; 18. Temperature regulating bypass valve actuation hose. Detailed Implementation

[0023] To make the structure and function of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings.

[0024] After a period of long-term operation, the Atlas Copco GA250 screw compressor failed to unload when it reached the set upper limit unloading condition. Furthermore, the loading / unloading solenoid valve continuously vented air during unloading, whereas during normal unloading, the solenoid valve vented air instantly, causing the compressor's load valve to close under spring action. The incomplete venting of compressed air in the air path during unloading indicated that compressed air was entering, causing the compressor's load valve to open and preventing unloading. Initially, internal leakage in the loading / unloading solenoid valve was suspected. After stopping the machine and checking, no internal leakage was found. Fearing internal leakage during loading / unloading, the solenoid valve was replaced. Upon restarting and testing, the loading / unloading solenoid valve exhibited the same problem. Subsequently, all air paths were purged, revealing no blockages, only significant moisture in the pipelines. Analysis of the control schematic and actual pipeline conditions indicated internal leakage in the temperature regulating bypass valve and piston valve. The temperature regulating bypass valve actuator was disassembled, revealing no damaged seals or leaks. Finally, the two piston valves on the two load valves were disassembled, revealing that one piston was cracked and damaged. After replacing the piston, the screw compressor was able to load / unload after restarting.

[0025] The above process requires disassembling and inspecting each valve in sequence, and then starting the air circuit for observation. The procedure is cumbersome, time-consuming, and labor-intensive, and it is easy to damage the components. In order to simplify the maintenance procedure, this invention provides a screw compressor load valve unloading maintenance control system and its maintenance method.

[0026] See appendix Figure 1 The screw compressor load valve unloading maintenance control system includes two load valves connected in parallel and a pressure vessel 1 connected to the two load valves. The pressure vessel 1 is connected to a solenoid valve supply hose 12, and an loading / unloading solenoid valve 2 is installed on the solenoid valve supply hose 12. The loading / unloading solenoid valve 2 is connected to a first load valve 4 through a first control circuit, and controls the operation of the first load valve 4 through the first control circuit. The loading / unloading solenoid valve 2 is connected to a second load valve 6 through a second control circuit, and controls the operation of the second load valve 6 through the second control circuit. The loading / unloading solenoid valve 2 is connected to a temperature regulating bypass valve 3 through a third control circuit, and controls the operation of the temperature regulating bypass valve 3 through the third control circuit. A first shut-off balloon valve 8 is installed between the loading / unloading solenoid valve 2 and the pressure vessel, a second shut-off balloon valve 9 is installed between the first load valve 4 and the pressure vessel 1, and a third shut-off balloon valve 10 is installed between the second load valve 6 and the pressure vessel 1.

[0027] Further, the first control loop includes a first load valve control hose 13 and a first load valve exhaust hose 14. The solenoid valve supply hose 12 is connected to the first load valve 4 via the first load valve control hose 13, and the pressure vessel 1 is connected to the first load valve 4 via the first load valve exhaust hose 14. The second control loop includes a second load valve control hose 15 and a second load valve exhaust hose 16. The solenoid valve supply hose 12 is connected to the second load valve 6 via the second load valve control hose 15, and the pressure vessel 1 is connected to the second load valve 6 via the second load valve exhaust hose 16. The third control loop includes a temperature regulating bypass valve control hose 17 and a temperature regulating bypass valve actuation hose 18. The solenoid valve supply hose 12 is connected to the temperature regulating bypass valve 3 via the temperature regulating bypass valve control hose 17, and the pressure vessel 1 is connected to the temperature regulating bypass valve 3 via the temperature regulating bypass valve actuation hose 18.

[0028] Furthermore, the first air-stop valve 8 is installed on the solenoid valve supply hose 12, the second air-stop valve 9 is installed on the first load valve exhaust hose 14, and the third air-stop valve 10 is installed on the second load valve exhaust hose 16.

[0029] Furthermore, the second gas shut-off valve 9 is mounted on the first load valve 4, and the first load valve 4 contains a first piston valve 5. The second gas shut-off valve 9 is connected to the air inlet pipe of the first piston valve 5, and the piston controls the entry and exit of gas. The third gas shut-off valve 10 is mounted on the second load valve 6, and the second load valve 6 contains a second piston valve 7. The third gas shut-off valve 10 is connected to the air inlet pipe of the second piston valve 7, and the piston controls the entry and exit of gas.

[0030] Furthermore, the first load valve control hose 13 is connected to the air intake control interface of the first load valve 4. When the screw compressor is loaded, the loading / unloading solenoid valve 2 opens, and compressed air enters through the air intake control interface to push the piston of the first load valve 4, opening the first load valve 4. When the screw compressor is unloaded, the loading / unloading solenoid valve 2 closes, and compressed air cannot enter. The compressed air in the first load valve 4 is discharged into the atmosphere through the air intake control interface, the first load valve control hose 13, and the other interface of the loading / unloading solenoid valve 2. The first load valve 4 closes under the action of the spring. The first load valve exhaust hose 14 is connected to the exhaust interface of the first load valve 4. During unloading, the compressed gas in the pressure vessel 1 is discharged through the internal passage of the first load valve 4 under the control of the first piston valve 5. Atmosphere; the second load valve control hose 15 is connected to the air intake control interface of the second load valve 6. When the screw compressor is loaded, the loading / unloading solenoid valve 2 opens, and compressed air enters through the air intake control interface to push the piston of the second load valve 6, opening the second load valve 6. When the screw compressor is unloaded, the loading / unloading solenoid valve 2 closes, and compressed air cannot enter. The compressed air in the second load valve 6 is discharged into the atmosphere through the air intake control interface, through the second load valve control hose 15, and through the other interface of the loading / unloading solenoid valve 2. The second load valve 6 is closed under the action of the spring; the second load valve exhaust hose 16 is connected to the exhaust interface of the second load valve 6. When unloading, the compressed gas in the pressure vessel 1 is discharged into the atmosphere through the internal passage of the second load valve 6 under the control of the second piston valve 7.

[0031] Furthermore, the loading / unloading solenoid valve 2 is connected to the control system 11 via a power supply circuit. The control system 11 is the control system of the loading / unloading solenoid valve 2 itself.

[0032] Furthermore, the pressure vessel 1 is a gas storage tank or an oil-gas separator.

[0033] The maintenance method for the screw compressor load valve unloading and maintenance control system includes the following steps:

[0034] Step 1: During normal startup, the loading and unloading solenoid valves of the screw compressor are in the open state when loading and in the closed state when unloading; the temperature regulating bypass valve is in different positions according to the oil temperature and loading and unloading status; under normal circumstances, the first cut-off valve, the second cut-off valve, and the third cut-off valve are in the open position.

[0035] Step 2: If the loading / unloading solenoid valve does not vent during screw compressor unloading operation, check the power supply circuit of the loading / unloading solenoid valve. If the terminal has 24VAC power, then the control system of the loading / unloading solenoid valve is faulty; if the loading / unloading solenoid valve vents (venting time is about 10 seconds), then the control system is normal.

[0036] Step 3: The loading / unloading solenoid valve continues to vent air. Close the first shut-off valve. If the loading / unloading solenoid valve does not vent air, it is faulty. If the loading / unloading solenoid valve vents air (venting time is about 10 seconds), it is normal.

[0037] Step 4: Open the first shut-off valve, close the second shut-off valve, and open the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the first load valve is faulty; if the loading / unloading solenoid valve vents air, the first load valve is normal.

[0038] Step 5: Open the first and second shut-off valves, and close the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the second load valve is faulty; if the loading / unloading solenoid valve vents air, the second load valve is normal.

[0039] Step Six: Close the first, second, and third shut-off valves. If the loading / unloading solenoid valve does not vent, it means that no gas is entering the solenoid valve control air path of the temperature regulation bypass valve. If the loading / unloading solenoid valve vents, it means that gas is entering the solenoid valve control air path of the temperature regulation bypass valve, and the sealing ring inside the temperature regulation bypass valve is damaged.

[0040] When an Atlas Copco GA250 screw compressor is running for an extended period and cannot unload, it is necessary to simultaneously check the loading / unloading solenoid valve circuit and air path, the load valve air path, the piston valve rubber piston, the sealing ring inside the temperature regulating bypass valve, and the air path connected to the air tank / oil-gas separator for unobstructed flow. This invention simplifies the process by addressing the numerous sub-items that require item-by-item screening during inspection. The specific principle and testing process are as follows.

[0041] When the outlet pressure of the Atlas Copco GA250 screw compressor exceeds the upper limit of the working pressure setting (8.4 bar), the loading / unloading solenoid valve 2 (hereinafter referred to as the solenoid valve) will be de-energized. The plunger of solenoid valve 2 will cut off the pressure supply from the pressure vessel, typically the air tank / oil-gas separator (hereinafter referred to as the air tank), to the load valve chamber. The control pressure in the chamber is released to the atmosphere through the solenoid valve (exhaust time is approximately 10 seconds). The load valve closes under the action of the spring force. The piston valve spring side loses pressure and is pressed down, releasing the air tank pressure to the air inlet through the hose and the load valve exhaust passage. A small amount of air is drawn in through the micro-holes and discharged to the air inlet through the screw, air tank, hose, and load valve exhaust passage; compressed air output stops, and the screw compressor operates under unloading conditions. The following details the improvement method for the screw compressor load valve's inability to unload: Install a first shut-off balloon valve 8 on the hose connecting the air tank and the loading / unloading solenoid valve 2. The valve is mounted on the air tank for easy operation and fixation. Install a second shut-off balloon valve 9 on the hose connecting the air tank and the first load valve 4. The valve is mounted on the first load valve 4 for easy operation and fixation. Install a third shut-off balloon valve 10 on the hose connecting the air tank and the second load valve 6. The valve is mounted on the second load valve 6 for easy operation and fixation. During the unloading process, if the solenoid valve 2 does not vent, use a multimeter to measure points a and b of the solenoid valve's power supply circuit. If there is 24VAC power, the problem is a control system malfunction (mostly due to contact adhesion). Troubleshoot according to the circuit control principle. If the solenoid valve's vent is blocked, use a probe to clear the blockage. If solenoid valve 2 continues to vent, first close the first shut-off valve 8 on the gas tank to cut off the gas supply to the solenoid valve. If solenoid valve 2 does not vent at this point, it is a faulty solenoid valve; remove and clean or replace it. If solenoid valve 2 still vents, it is not the problem; open the first shut-off valve 8. Next, close the second shut-off valve 9. If solenoid valve 2 does not vent at this point, it indicates an internal leak in the first piston valve 5 of the first load valve 4; disassemble and repair the first piston valve 5, replacing the piston. If solenoid valve 2 still vents, the first piston valve 5 is not the problem; open the second shut-off valve 9. Next, close the third shut-off valve 10. If solenoid valve 2 does not vent at this point, it indicates an internal leak in the second piston valve 7 of the second load valve 6; disassemble and repair the second piston valve 7, replacing the piston. If solenoid valve 2 still vents, the second piston valve 7 is not the problem. Close all three ball valves. If solenoid valve 2 does not vent, it indicates that no gas is entering the solenoid valve control circuit of temperature regulating bypass valve 3. If the solenoid valve still vents, it indicates that gas is entering the solenoid valve control circuit of temperature regulating bypass valve 3, suggesting that the inner sealing ring of temperature regulating bypass valve 3 is damaged. Remove the actuator of temperature regulating bypass valve and replace the inner sealing ring. By installing three ball valves, the complex and tedious troubleshooting of screw compressor failure to unload is simplified, reducing workload and allowing the fault to be resolved more quickly. Figure 1This is a simplified control flowchart for a screw compressor that cannot be unloaded. Due to the complex structure of the screw compressor, not all control diagrams for the screw compressor are shown.

[0042] The inability of a screw compressor to unload can have many causes, requiring disassembly and troubleshooting of each component, which is labor-intensive and makes it difficult to directly pinpoint the cause of the malfunction. This invention simplifies and streamlines the process by installing three valves at appropriate locations in the pneumatic control circuit, making it easier for technicians to determine the cause of the unloading failure.

[0043] The above examples are merely preferred embodiments of the present invention. Obviously, the present invention is not limited to the above embodiments, and many variations are possible. All variations that can be directly derived or conceived by those skilled in the art from the disclosure of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A screw compressor load valve unloading and maintenance control system, characterized in that: The system includes two load valves connected in parallel and a pressure vessel connected to the two load valves. The pressure vessel is connected to a solenoid valve supply hose. An loading / unloading solenoid valve is installed on the solenoid valve supply hose. The loading / unloading solenoid valve is connected to the first load valve via a first control circuit, to the second load valve via a second control circuit, and to a temperature regulating bypass valve via a third control circuit. A first shut-off balloon valve is installed between the loading / unloading solenoid valve and the pressure vessel, a second shut-off balloon valve is installed between the first load valve and the pressure vessel, and a third shut-off balloon valve is installed between the second load valve and the pressure vessel. The first control loop includes a first load valve control hose and a first load valve exhaust hose. The solenoid valve supply hose is connected to the first load valve through the first load valve control hose, and the pressure vessel is connected to the first load valve through the first load valve exhaust hose. The second control loop includes a second load valve control hose and a second load valve exhaust hose. The solenoid valve supply hose is connected to the second load valve through the second load valve control hose, and the pressure vessel is connected to the second load valve through the second load valve exhaust hose. The third control loop includes a temperature regulating bypass valve control hose and a temperature regulating bypass valve actuation hose. The solenoid valve supply hose is connected to the temperature regulating bypass valve through the temperature regulating bypass valve control hose, and the pressure vessel is connected to the temperature regulating bypass valve through the temperature regulating bypass valve actuation hose.

2. The screw compressor load valve unloading and maintenance control system according to claim 1, characterized in that: The first air-stop valve is installed on the solenoid valve supply hose; the second air-stop valve is installed on the first load valve exhaust hose; and the third air-stop valve is installed on the second load valve exhaust hose.

3. The screw compressor load valve unloading and maintenance control system according to claim 1, characterized in that: The second air-stop valve is mounted on the first load valve, which contains a first piston valve, and the second air-stop valve is connected to the air inlet pipe of the first piston valve; the third air-stop valve is mounted on the second load valve, which contains a second piston valve, and the third air-stop valve is connected to the air inlet pipe of the second piston valve.

4. The screw compressor load valve unloading and maintenance control system according to claim 1, characterized in that: The first load valve control hose is connected to the air intake control port of the first load valve, and the first load valve exhaust hose is connected to the exhaust port of the first load valve; the second load valve control hose is connected to the air intake control port of the second load valve, and the second load valve exhaust hose is connected to the exhaust port of the second load valve.

5. The screw compressor load valve unloading and maintenance control system according to claim 1, characterized in that: The loading and unloading solenoid valve is connected to the control system via a power supply circuit.

6. The screw compressor load valve unloading and maintenance control system according to claim 1, characterized in that: The pressure vessel is a gas storage tank or an oil-gas separator.

7. A maintenance method for a screw compressor load valve unloading and maintenance control system as described in any one of claims 1-6, characterized in that, Includes the following steps: Step 1: The first, second, and third air release valves are in the open position; Step 2: If the loading / unloading solenoid valve does not vent during screw compressor unloading operation, check the power supply circuit of the loading / unloading solenoid valve. If the wiring terminal has 24VAC power, then the control system of the loading / unloading solenoid valve is faulty; if the loading / unloading solenoid valve vents, then the control system is normal. Step 3: The loading / unloading solenoid valve continues to vent air. Close the first shut-off valve. If the loading / unloading solenoid valve does not vent air, it is faulty; if it vents air, it is working properly. Step 4: Open the first shut-off valve, close the second shut-off valve, and open the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the first load valve is faulty; if the loading / unloading solenoid valve vents air, the first load valve is normal. Step 5: Open the first and second shut-off valves, and close the third shut-off valve. If the loading / unloading solenoid valve does not vent air, the second load valve is faulty; if the loading / unloading solenoid valve vents air, the second load valve is normal. Step Six: Close the first, second, and third shut-off valves. If the loading / unloading solenoid valve does not vent, it means that no gas is entering the solenoid valve control air path of the temperature regulation bypass valve. If the loading / unloading solenoid valve vents, it means that gas is entering the solenoid valve control air path of the temperature regulation bypass valve, and the sealing ring inside the temperature regulation bypass valve is damaged.

8. The maintenance method for the screw compressor load valve unloading and maintenance control system according to claim 7, characterized in that, In step two, the power supply circuit of the loading and unloading solenoid valve is tested using a multimeter.

9. The maintenance method for the screw compressor load valve unloading and maintenance control system according to claim 7, characterized in that, In step four, the fault of the first load valve is internal leakage in the first piston valve within the first load valve; in step five, the fault of the second load valve is internal leakage in the second piston valve within the second load valve.

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