Do you know the advantages and disadvantages of piston compressors, rolling rotor compressors, scroll compressors, screw compressors and centrifugal compressors? Today, I will explain to you in detail about these five kinds of compressors. I hope to be useful to everyone! First, the piston compressor When the crankshaft of the piston compressor rotates, the piston reciprocates through the transmission of the connecting rod, and the working volume formed by the inner wall of the cylinder, the cylinder head and the top surface of the piston periodically changes. When the piston of the piston compressor starts to move from the cylinder head, the working volume in the cylinder gradually increases. At this time, the gas moves along the intake pipe and pushes the intake valve into the cylinder until the working volume becomes large. When the piston of the piston compressor moves in the reverse direction, the working volume in the cylinder is reduced, and the gas pressure is increased. When the pressure in the cylinder reaches and is slightly higher than the exhaust pressure, the exhaust valve is opened and the gas is discharged from the cylinder. The exhaust valve closes until the piston moves to the extreme position. The above process occurs repeatedly when the piston of the piston compressor moves in the opposite direction. In short, the crankshaft of the piston compressor rotates once, the piston reciprocates once, and the process of intake, compression, and exhaust is successively performed in the cylinder, that is, a working cycle is completed. 1. Advantages of piston compressor (1) Regardless of the flow rate, the required pressure can be obtained, and the exhaust pressure range is wide. The high pressure of Zui can reach 320MPa (industrial application) or even 700MPa (in the laboratory); (2) The stand-alone capability is any flow below 500m3/min; (3) In the general pressure range, the requirements for materials are low, and ordinary steel materials are used, which is easy to process and low in cost; (4) The thermal efficiency is high, and the adiabatic efficiency of large and medium-sized units can reach 0.7~0.85; (5) When the gas volume is adjusted, the adaptability is strong, that is, the exhaust gas range is wide, and it is not affected by the pressure level, and can adapt to a wider pressure range and cooling capacity requirement; (6) The severity and characteristics of the gas have little effect on the performance of the compressor, and the same compressor can be used for different gases; (7) The drive machine is relatively simple, most of them use electric motors, generally no speed regulation, and maintainability is strong; (8) Piston compressors are relatively mature in technology and have accumulated rich experience in production and use; 2, the disadvantages of the piston compressor (1) The structure is complex and cumbersome, with many wearing parts, large floor space, high investment, large maintenance workload, short service period, but can reach more than 8000 hours after hard work; (2) The speed is not high, the machine is large and heavy, and the single engine displacement is generally less than 500m3/min; (3) There is vibration during the operation of the machine; (4) The exhaust gas is discontinuous, the airflow is pulsating, which is easy to cause the pipeline to vibrate. In severe cases, the pipe network or the mechanical parts are often damaged due to the pulsation and resonance of the airflow; (5) The flow adjustment adopts the auxiliary volume or bypass valve. Although it is simple, convenient and reliable, the power loss is large, and the efficiency is reduced during partial load operation; (6) Oil-lubricated compressors, with oil in the gas to be removed; (7) When a large-scale factory adopts multiple compressor units, there are many operators or work intensity. Second, rolling rotor compressor The rolling rotor type compressor is a volumetric type rotary compressor, and the change in the working volume of the cylinder is achieved by rolling of a cylindrical rotor of an eccentric device in the cylinder. 1. The rotor rotates one revolution and will complete the compression and exhaust process of the previous working cycle and the suction process of the next working cycle. 2. Since there is no steam inlet valve, there is a strict correspondence between the timing of inhalation start and the position of the suction port on the cylinder, and it does not change with the change of working conditions. 3. Since the exhaust valve is installed, the timing of the end of compression will vary with the pressure in the exhaust pipe. 1, advantages Such compressors are now also commonly used in household refrigerators and air conditioners, and their advantages are: (1) The structure is simple, the volume is small, and the weight is light. Compared with the piston compressor, the volume can be reduced by 40% to 50%, and the weight can be reduced by 40% to 50%; (2) The number of parts is small, especially the wearing parts are small, and the friction loss between the moving parts is small, so the reliability is high; (3) Only the sliding piece has a small reciprocating inertial force, the rotating inertial force can be completely balanced, the rotating speed can be high, and the vibration is small, and the operation is stable; (4) There is no inhalation valve, the inhalation time is long, the clearance volume is small, and the air is directly inhaled, which reduces the harmful inhalation of the inhalation, so the efficiency is high. However, its processing and assembly accuracy requirements are high. Since there is no air valve, it can be used to transport dirty and dust-containing process gases. 2, disadvantages The main disadvantage of the rotary compressor is that the leakage, friction and wear between the sliding vane and the cylinder wall surface are large, which limits its working life and efficiency; and the processing precision of the compressor is high. If a double-layer sliding piece is used, the ends of the two sliding pieces are kept in contact with the inner wall of the cylinder during operation to form two sealing lines, and an oil seal is formed between the two sealing lines, which greatly reduces the leakage loss at the end of the sliding piece. Reduce friction and friction losses, resulting in improved machine life and efficiency. Once the compressor wears at its bearing, main shaft, roller or slide, the gap increases and it will immediately have a significant adverse effect on its performance. Therefore, it is usually used in the refrigerator and air conditioner assembled in the factory. In the system, high cleanliness is also required in the system. Third, scroll compressor The main components in a scroll compressor are two involute scrolls of the same shape but with an angular phase offset of 180°, one of which is a fixed scroll and the other is driven by an eccentric shaft. A whirling scroll that revolves the axis of the fixed scroll. In operation, the two scrolls are tangent at multiple locations to form a seal line, and a proper seal at the end faces of the two scrolls is formed to form a cavity for several months. The sealing line at the common tangent point between the two scrolls is continuously transferred along the vortex curve as the orbiting scroll revolves, so that the shape and shape of these crescent-shaped air chambers are constantly changing. The suction port of the compressor is opened at the upper portion of the fixed scroll housing. When the eccentric shaft rotates clockwise, the gas enters the suction chamber from the suction port, and is successively taken into the peripheral crescent-shaped air chamber communicating with the suction chamber. As these peripheral crescent-shaped air chambers are closed and no longer communicate with the suction chamber, their closed volume is gradually transferred to the center of the fixed scroll and shrinks, and the gas is continuously compressed and the pressure is increased. 1, advantages From the specific structure, the scroll compressor has no suction and exhaust valves, which greatly improves the reliability of high-speed operation. Taken together, the scroll compressor has the following main features: (1) It belongs to the third-generation compressor, and multiple compression chambers work at the same time. The gas pressure difference between adjacent compression chambers is small, the gas leakage is small, and the volumetric efficiency is high, up to 98%, compared with the second-generation compressor rotor. The compressor efficiency is about 5%; (2) The eccentric shaft that drives the motion of the orbiting scroll can be rotated at a high speed, and therefore, the scroll compressor is small in size and light in weight; (3) The force change of the moving parts such as the movable scroll and the main shaft is small, and the vibration of the whole machine is small; (4) Without suction and exhaust valves, the scroll compressor operates reliably, and is especially suitable for variable speed motion and variable frequency speed control technology; (5) The compression chamber of the scroll compressor is composed of a scroll type line, which is a multi-chamber compression mechanism. When the center of the orbiting scroll moves circularly around the center of the fixed scroll, the volume of each compression chamber changes with the rotation angle of the main shaft. It will be correspondingly reduced or enlarged, thereby realizing the process of gas suction, compression and exhaust. Since the process of suction and exhaust is almost continuous, the noise of the whole machine is very low; (6) The axial and radial flexible structure improves the production efficiency of the scroll compressor, and ensures the sealing effect of the axial clearance and the radial clearance, which is not reduced by friction and wear, that is, the scroll compressor is reliable and effective. The sealing property, so its refrigeration coefficient does not decrease with the increase of running time, but slightly increases; (7) The scroll compressor has good working characteristics, and its performance is mainly affected by its own compression ratio and suction pressure. The exhaust pressure range is wide, suitable for various indoor and outdoor environments, ensuring that the compressor has been running at high energy efficiency ratio. In order to ensure the energy efficiency ratio of the air conditioning unit. In the heat pump air conditioning system, it is particularly characterized by high heating performance, good stability and high safety; (8) The scroll compressor has no clearance volume and is multi-chamber compression in structure. The pressure difference between adjacent chambers is not very large (approximate continuous change). At the same time, the sealing strips of the end faces of the moving and stationary scrolls are closed. The axial back pressure is compressed so that the moving and stationary scrolls are in close contact, and a good sealing effect is achieved with the help of the freezing oil, so that the inner leakage is almost non-existent; when the end surface of the sealing strip is worn, it can be along the shaft Automatically compensated in the direction to ensure that the end faces of the movable scroll and the bottom of the fixed scroll are always tightly attached, and the longer the working time of the compressor, the better the fit of these close relative moving surfaces, and the better the sealing effect, these advantages make the vortex The rotary compressor does not have the problem of secondary compression of refrigerant gas, and is one of the important guarantee factors for maintaining high volumetric efficiency; (9) The torque variation is small, the balance is high, the vibration is small, the operation is stable, and the operation is simple and easy to realize automation; (10) Because it has few moving parts and no reciprocating mechanism, it has a simple structure, small size, light weight, few parts (especially less wearing parts), high reliability, and a service life of more than 20 years. 2, disadvantages (1) The surface of the moving parts is mostly curved, and the processing and inspection of these surfaces are complicated. The manufacturing equipment with high precision and precise alignment assembly technology are required, so the manufacturing cost is high. (2) Between the moving parts or between the moving parts and the fixed parts, the sealing is often achieved by maintaining a certain movement gap, and the gas passing through the gap is bound to cause leakage, which limits the difficulty of the rotary compressor to reach a large Compression ratio, therefore, most rotary compressors are used in air conditioning conditions. Fourth, screw compressor The screw compressor is formed by a meshing of a male rotor composed of five convex teeth (hereinafter referred to as an M rotor) and a female rotor composed of six concave teeth (hereinafter referred to as an F rotor) to form a tooth-shaped space suction refrigerant, by reducing The toothed space compresses the refrigerant to a predetermined pressure. The workflow of the screw compressor is as follows: [inhalation stroke] The refrigerant is sucked from a suction port that is open in the axial direction to the radial direction. As the rotor rotates, on the lower side of the rotor, the meshing is separated, the length of the groove increases, and the refrigerant is sucked into the toothed space. [compression stroke] The tooth shape is engaged from the suction side of the tooth groove, and the seal line gradually travels toward the discharge side, and the tooth space is reduced to be compressed. An oil film seal is formed in the rotor gap by the lubricating oil sucked together with the refrigerant, and the rotor is lubricated. The male rotor and the female rotor are gradually compressed near the discharge port, and the pressure is increased. [discharge route] The toothed space is connected to the discharge port to start the discharge stroke. This stroke continues until the discharge end until the refrigerant in the toothed space is completely delivered. 1, advantages (1) Less parts, less wearing parts and high reliability; (2) Convenient operation and maintenance; (3) There is no unbalanced inertial force. The operation is stable and safe, and the vibration is small; (4) It has the characteristics of forced gas transmission, and the displacement is almost independent of the exhaust pressure, and the working condition is adaptable; (5) The rotor tooth surface of the screw compressor is actually gapped. Therefore, it is not sensitive to wet stroke and can withstand liquid hammer; (6) The exhaust gas temperature is low and can be operated under higher pressure ratio conditions: (7) It can realize stepless adjustment of cooling condition, adopting sliding valve mechanism, so that the cooling capacity can be adjusted steplessly from 15% to 100%, saving operating costs; (8) It is easy to automate and realize remote communication. 2, disadvantages (1) The rotor tooth surface is a space curved surface. It needs to be made with a special knife. It is processed on expensive equipment, and the machining accuracy of the body parts is also high. High-precision equipment must be used: (2) Since the volume between the teeth is periodically connected to the suction and exhaust ports, the compressor noise is high; (3) Due to the limitation of rotor stiffness and bearing life, the compressor can only rely on the gap seal, so the screw compressor can only be used in the medium and low pressure range, and can not be used in high pressure applications; (4) Due to the large amount of fuel injection and the complicated oil treatment system, there are many auxiliary equipments for the unit; (5) The screw compressor relies on the gap sealing gas and does not have superior performance in a small volume range. Five, centrifugal compressor The construction and operation of a centrifugal refrigeration compressor is very similar to that of a centrifugal blower. However, its working principle is fundamentally different from that of a piston compressor. Instead of using a cylinder volume reduction method to increase the pressure of the gas, it relies on changes in kinetic energy to increase the gas pressure. The centrifugal compressor has a bladed working wheel. When the working wheel rotates, the blade drives the gas to move or the gas to obtain kinetic energy, and then converts part of the kinetic energy into pressure energy to increase the pressure of the gas. This type of compressor is called a centrifugal compressor because it continuously draws in refrigerant vapor while it is being continuously sucked out in the radial direction. 1, advantages (1) Centrifugal compressor has large gas volume, simple and compact structure, light weight, small unit size and small floor space. Compared with piston compressor, when the cooling capacity is the same, the weight is 5-8 times lighter than the piston type. (2) Because it does not have vulnerable parts such as steam valve piston rings, and there is no crank linkage mechanism, the operation is balanced, the operation is reliable, the operation rate is high, and the friction parts are small, so the spare parts need less usage, the maintenance cost and the personnel are small. (3) There is no friction between the working wheel and the casing, no lubrication is required. In the chemical process, centrifugal compressors can achieve an absolutely oil-free compression process for chemical media. (4) Centrifugal compressor is a kind of rotary motion machine, which is suitable for direct dragging of industrial steam turbines or gas turbines. For general large-scale chemical plants, it is often used as a by-product steam-driven industrial steam turbine to provide power for comprehensive utilization of thermal energy. 2, disadvantages (1) Centrifugal compressors are not suitable for occasions where the gas volume is too small and the pressure ratio is too high, and since it is suitable to use a relatively large molecular weight refrigerant, it is only suitable for large refrigeration capacity, generally in the range of 25 to 300,000. Card / time above. (2) The stable working condition area of ​​the centrifugal compressor is narrow, and the gas volume adjustment is convenient, but the economy is poor. (3) At present, the efficiency of centrifugal compressors is generally lower than that of piston compressors. (4) Generally, it is necessary to use a speed-increasing gear transmission, which has a high rotation speed and high requirements on the shaft end seal, which increases the manufacturing difficulty and the structural complexity. Second-Hand Rapier Loom,Air Jet Loom,Water Jet Loom,Electronic Jacquard Machine,Second-Hand Weaving Machine,Textile Machinery Changzhou Satidi Import and Export Co., Ltd. , https://www.czguanjiechuck.com
