The past and present situation of domestic screw compressors
As early as the early 1970s, China had already manufactured and applied screw compressors. At that time, the defects in the manufacturing precision and the service life, to a certain extent, have led to the breadth and depth of its development. Until after the reform and opening up, bearing, seal, foreign advanced control instruments have been imported or joint production, coupled with their own design and manufacture of screw compressor technology by the introduction of foreign advanced equipment, management or joint production, with the rapid development of oil refining, into, coal chemical industry, fine chemical industry gradually.
A summary of 2 screw air compressors
Screw type air compressor is the injection of single stage double screw compressor, efficient use of belt wheel (or axis) rotation drive, driven by a host of compressed air, through the injector to host the compression chamber for cooling and lubrication, compressed air and oil mixed gas chamber is discharged through a rough, fine two separated, the oil in compressed air isolated, finally get the clean compressed air.
The twin screw air compressor has excellent reliability. It has the advantages of light weight, small vibration, low noise, easy operation, less wearing parts and high efficiency.
Introduction of the principle of 3 screw compressor
The screw type compressor cylinder is equipped with a pair of Intermeshing Helical yin-yang rotors, and the two rotors have several concave teeth. Both of them rotate each other in reverse. The gap between the rotor and the casing and the rotor is only 5~10 wires, the main rotor (also known as the male rotor or convex rotor), driven by a motor or engine (mostly motor drive), a rotor (also known as the female rotor rotor or concave) is oil film formed by the main rotor through the injector for driving, or by the main rotor and rotor end of the concave end synchronous gear drive. The length and diameter of the rotor determine the exhaust volume (flow) and exhaust pressure of the compressor. The longer the rotor is, the higher the pressure, the greater the diameter of the rotor, the greater the flow.
The spiral rotor groove is filled with gas through the suction port. When the rotor is rotated, the groove of the rotor is closed by the shell wall to form a compression chamber. When the rotor groove is closed, the lubricating oil is injected into the compression chamber and is sealed. Cooling and lubrication. When the rotor rotates and compresses the lubricant + gas (the oil gas mixture), the compressed chamber volume decreases and the oil and gas mixture is compressed to the exhaust port. When the compressed chamber passes through the vent, the mixture of oil and gas is discharged from the compressor to complete a suction - compression - exhaust process. Each rotor of the screw machine is supported by the antifriction bearing, and the bearing is fixed by the end cover near the end of the rotating shaft. The intake end is supported by roller bearings, and the exhaust port is supported by a pair of roller bearings, usually the exhaust port bearing, so that the rotor can be positioned, that is, thrust bearing, resisting axial thrust, bearing radial load, and providing the minimum axial clearance required.
The working cycle can be divided into three processes: suction, compression and exhaust. As the rotor rotates, each pair of meshing teeth successively completes the same working cycle.
Advantages of 4 screw compressors
(1) the screw compressor is the same as the piston compressor, all of which belong to the volumetric compressor. The use effect of the screw air compressor has the following advantages.
(2) high reliability. Screw compressor parts less, no vulnerable parts, so it runs reliable, long life, the interval of large repair up to 4~8 million hours.
(3) convenient operation and maintenance. Screw compressor automation is high, the operator does not have to pass a long time professional training, can realize unmanned operation.
(4) the balance of power is good. The screw compressor has no unbalanced inertia force, and the machine can work at a steady and high speed. It can operate without foundation. It is especially suitable for mobile compressors, with small volume, light weight and less floor area.
(5) strong adaptability. Screw compressor has the characteristics of forced gas transmission, volume flow is almost not affected by exhaust pressure, and it can maintain high efficiency in a wide range. Under the condition of no change of compressor structure, it can be applied to various conditions.
Problems of 5 screw compressor
In the past, the reciprocating compressor was more aware than the other types of compressor, and it was not easy to use the screw compressor. Now the screw compressor installation, commissioning, maintenance and maintenance of technical ability, management ability, the education level has a significant progress, the vulnerability of screw compressor, long operation period, resistance to liquid resistance, dust resistance, tar, gas and has the advantages of small volume, with a full set understanding, they hope to adopt screw compressor in some special process section.
(1) to meet the requirements of low pressure and large volume, it is necessary to increase the capacity of the cylinder. At present, the diameter of the first cylinder has achieved the record of 1.5m, and it often needs 2 or even 3 parallel connections. The problem is as follows.
The requirements of large-scale processing equipment parts, increase manufacturing cost; influence of column spacing by the compressor, the maintenance space becomes narrow, difficult maintenance; the diameter is too large to pressure process cylinder liner traditional challenges, if there is no liner, once the mirror surface wear (which is inevitable). It can replace the cylinder body! Considerable economic loss; the large cylinder will use air valve, air valve installation, replacement, like lifting the barbell, the labor intensity of workers is considerable; the piston body with large friction force, is bound to increase the support ring, support ring up damage.
(2) the valve, the piston ring is a vulnerable part, especially when the gas contains coal tar, dust and other harmful substances.