Working principle diagram and precautions of screw air compressor Working principle diagram of twin screw air compressor 1. Basic structure and working principle The commonly known screw compressor refers to the twin screw compressor. The basic structure of the screw compressor: In the collective of the compressor, a pair of interlocking spiral rotors are arranged in parallel. Usually the rotor with convex teeth outside the pitch circle is called the male rotor or male screw. The rotor with concave teeth in the pitch circle is called the female rotor or female rotor Generally, the male rotor is connected to the prime mover, and the female rotor drives the female rotor to rotate The last pair of bearings on the rotor achieve axial positioning and bear the axial force in the compressor. Cylindrical roller bearings at both ends of the rotor enable the rotor to achieve radial positioning and withstand radial forces in the compressor. At both ends of the compressor body, openings of a certain shape and size are opened respectively. One for intake, called the air intake; the other for exhaust, called the exhaust. Working principle: The working cycle of screw compressor can be divided into three processes: intake, compression and exhaust. As the rotor rotates, each pair of intermeshing teeth sequentially completes the same working cycle.
1. Intake process: when the rotor rotates, the space of the tooth groove of the male and female rotors is turned to the opening of the intake end wall, and the space is the largest. At this time, the space of the rotor groove is communicated with the air inlet. The gas is completely discharged. When the exhaust is completed, the tooth groove is in a vacuum state. When it is turned to the air inlet, the external gas is sucked into the tooth groove of the Yin and Yang rotor in the axial direction. When the gas fills the entire tooth groove, the end face of the rotor intake side turns away from the air inlet of the casing, and the gas in the tooth groove is closed. 2. Compression process: When the suction of the Yin-Yang rotor ends, the tip of the Yin-Yang rotor will be closed with the casing, and the gas will no longer flow out in the tooth groove. The engaging surface gradually moves toward the scheduling end. The space of the tooth groove between the meshing surface and the exhaust port is gradually reduced, and the pressure of the gas in the tooth groove is increased by the compression. 3. Exhaust process: When the meshing end face of the rotor turns to communicate with the exhaust port of the casing, the compressed gas begins to be exhausted until the tooth surface of the tooth tip and the groove moves to the exhaust end face. The tooth groove space between the meshing surface and the exhaust port of the casing is 0, that is, the exhaust process is completed, at the same time, the length of the tooth groove between the meshing surface of the rotor and the intake port of the chassis reaches the longest, and the intake process is again get on. It can be seen from the above working principle that the screw compressor is a volumetric gas compression machine with a working volume for rotary motion. The compression of the gas depends on the change in volume, and the change in volume of oil is achieved by a pair of rotors of the compressor, which can then be rotated inward. The characteristics of screw compressors: As far as the principle of gas pressure is concerned, screw compressors are the same as piston compressors, and are all positive displacement compressors. In terms of the movement form of the main components, it is similar to the centrifugal compressor. Therefore, the screw compressor has the characteristics of the above two types of compressors. Advantages of screw compressor: 1. High reliability: The screw compressor has few parts and no wearing parts, so it operates reliably and has a long service life. The interval between overhauls can reach 40,000-80,000 hours. 2. Convenient operation and maintenance: the operator does not need professional training, and can realize unattended operation. 3. Good power balance: the screw compressor has no unbalanced inertial force, the machine can work smoothly at high speed, and it can be operated without foundation. 4. Strong adaptability: The screw compressor has the characteristics of forced gas transmission, and the discharge volume is almost not affected by the discharge pressure, and it can ensure higher efficiency in a wide range. 5. Multi-phase mixed transmission: The rotor tooth surface of the screw compressor actually has a gap, so it can resist liquid impact, and can send liquid-containing gas, dust-containing gas, and easily polymerized gas. Disadvantages of screw compressors: 1. High cost: The rotor surface of the screw compressor is a space curved surface, which requires special tools and expensive special equipment for processing. In addition, the machining accuracy of the screw compressor cylinder is also higher. 2. Unsuitable high-pressure occasions: Due to the limitations of rotor stiffness and bearing life, screw compressors can only be applied to medium and low pressure ranges, and the discharge pressure generally cannot exceed 3.Mpa. 3. Can not be made into miniature: screw compressors rely on gap seal gas, currently only when the volume flow is greater than 0.2m3/min, the screw compressor has superior performance. Screw air compressor operating procedures 1. The operator must be familiar with the mechanism, performance, working principle, operating procedures and precautions of the air compressor. 2. Operators must go through technical training and safety training. After passing the examination, they should take the post with a certificate and do not operate without a certificate. 3. Check before starting: 1. Check the capacity of lubricating oil in the oil and gas separator. After normal operation, the oil level in the oil level gauge is best above the middle of the upper and lower limits. 2. Check whether the air supply pipeline is unblocked, all bolts and joints are fastened with stone Buddha. 3. Check whether the various instrument indications on the low-voltage distribution cabinet are correct, whether the electrical wiring is intact, and whether the grounding wire conforms to the standard. 4. During the test run, about 0.5 liters of lubricating oil should be added from the air inlet and used for the number of rotations or jogs to prevent the compressor from losing oil and burning during startup. Pay special attention not to let foreign objects fall into the body to avoid damage. compressor. 5. Before starting, the compressor exhaust valve should be opened and the manual drain valve should be closed. The operator should be in a safe position. 4. Operation procedures: 1. Preparation before starting: Check the oil level in the oil and gas separator, open the drain valve under the oil and gas separator slightly to eliminate possible condensate during the period, and tighten this valve after confirming that there is no condensate; open the air supply port of the compressor valve. 2. Turn on: close the power switch, turn on the power, observe whether there is abnormal display on the operation panel, whether the phase sequence is correct, if there is abnormal display, the power should be cut off immediately, and it can be put into use after fault care, the machine has reverse protection, the motor Reverse is strictly prohibited. 3. Start: Press the "ON" button on the control panel, the compressor starts to operate according to the set mode. At this time, you should observe whether the various parameters on the hi panel that are scaring you are normal (the pressure does not exceed 0.85MPa, the exhaust temperature does not exceed 105℃), whether there are abnormal sounds, whether there is oil leakage, if any, you must immediately stop and check . When starting up, turn on the master first, then turn on the slave after about 1 minute. 4. Stop: press the "OFF" button on the control panel, the compressor will stop after a certain period of time, and it is normal to stop it. When the machine is stopped, the slave machine should be stopped, and then the master machine. 5. If there is a special abnormality in the air compressor, you can press the emergency stop button, if you need to restart again, it will be 2 minutes later. 6. The air compressor is strictly prohibited to start with load, otherwise the electrical components will be damaged due to excessive starting current. 7. When the air compressor is not in use, the power supply should be cut off and the air supply valve of the compressor should be closed. Discharge the water accumulated in the cooler, oil-water separator, exhaust pipe and air bag. 8. When shutting down for maintenance, you must open the knife gate of the power cabinet and list and ground it. 5. Inspection and precautions during operation: 1. Check whether the indication of various electrical instruments is normal. 2. Listen for any changes in the sound of the principalities of the Principality of the machine. 3. Check that the temperature of each component does not exceed the specified value. 4. Check whether the lubricating oil level is normal, and it is forbidden to touch the rotating parts during operation. 5. When replacing the oil and gas separator, pay attention to the discharge of static electricity, and connect the inner metal mesh with the outer shell of the oil drum to prevent the explosion caused by the accumulation of static electricity. At the same time, it is necessary to prevent unclean items from falling into the oil drum, so as not to affect the operation of the compressor. 6. The compressor will automatically stop when it runs for no load for more than the set time. At this time, it is absolutely not allowed to carry out inspection or maintenance work, because the compressor will resume operation at any time. For the unit with a separate fan, the operation of the fan is automatically controlled, and the fan must not be touched to avoid personal injury. The power must be cut off before mechanical inspection.
