A lot of people will consider whether to use screw air compressor or piston air compressor when choosing air compressor. In fact, the performance and structure of these two air compressors are completely different. Please see below for details. . .
1. Piston type oil-free lubrication air compressor
Piston type oil-free lubrication air compressor consists of compressor main engine, cooling system, regulation system, Lubrication system, safety valve, motor and control equipment. The compressor and the motor are fastened to the base by bolts, and the base is fixed to the foundation by anchor bolts. During operation, the motor directly drives the crankshaft through the coupling, drives the connecting rod, the crosshead and the piston rod, so that the piston reciprocates in the cylinder of the compressor to complete the processes of suction, compression and discharge. The machine is a double-acting compressor, that is, the piston moves up and down, and the air is sucked, compressed and discharged.
The piston ring in the cylinder of the oil-free lubrication air compressor and the packing in the packing device are filled with PTFE with self-lubricating properties as the sealing element. Therefore, the cylinder and the packing device do not need to be lubricated with lubricating oil. Under normal circumstances, the compressed gas is substantially pure and free of oil, and there is no need to add a degreasing device. The shortcomings of this machine are that the motor power is too large, the exhaust pressure is not stable enough, the exhaust temperature is high, the noise is too large, the maintenance work is large, and the maintenance cost is high.
2.Screw air compressor
Screw air compressor consists of screw head, electric motor, oil and gas separation barrel, cooling system, air conditioning system , how to system, safety valve and control system. The whole machine is installed in a box body, which can be self-contained and placed directly on the flat concrete floor without fixing the foundation bolts. The screw head is a two-shaft positive displacement rotary compressor head. A pair of high-precision main (male) and secondary (female) rotors are horizontally and parallelly mounted inside the casing, the main (male) rotor has 5 teeth, and the secondary (female) rotor has 6 teeth. The main rotor has a large diameter and the secondary rotor has a small diameter. The teeth form a spiral and the two are in mutual engagement. Both ends of the main and auxiliary rotors are respectively supported by bearings. During operation, the motor is directly injected into the rotor toothing portion through the nozzle of the lower part of the compressor casing through the coupling, and is mixed with the air to take away the heat generated by the compressor to achieve the cooling effect. At the same time, a liquid film is formed to prevent direct contact between the metal and the metal between the rotors and to close the gap between the rotor and the casing. The injected coolant also reduces the noise generated by high speed compression.
The main components of the screw air compressor are the screw machine head and the oil and gas separation barrel. The screw head is inhaled through the suction filter and the intake control valve, and the oil is injected into the air compression chamber to cool, seal and lubricate the screw and the bearing, and the compression chamber generates compressed air. The oil and gas mixture generated after compression is discharged into the oil and gas separation tank. Due to mechanical centrifugal force and gravity, most of the oil is separated from the oil and gas mixture. The air passes through the oil and gas separation core made of borosilicate glass fiber, and almost all the oil mist is separated. The oil separated from the oil separation cylinder is returned to the screw head through the oil pipe. An oil filter is installed on the oil return pipe, and after the oil is filtered through the oil filter, the clean oil flows back into the screw head. When the oil is separated, the compressed air exits the cylinder through the minimum pressure control valve and enters the aftercooler. After the cooler, the compressed air is cooled and discharged to the gas tank for use by each gas unit. The condensed water is concentrated in the gas tank and discharged through an automatic drain or manually.