Structure and working principle

1. Piston-type oil-free lubrication air compressor

　　Piston-type oil-free lubrication air compressor is composed of compressor mainframe, cooling system, regulating system, lubrication system, safety valve, electric motor and control equipment. The compressor and the motor are fastened on the base with bolts, and the base is fixed on the foundation with anchor bolts. When working, the motor directly drives the crankshaft through the coupling, driving the connecting rod, crosshead and 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 upward and downward movement of the piston has air suction, compression and discharge.

　　2, screw air compressor

　　 Screw air compressor is composed of screw head, motor, oil and gas separation barrel, cooling system, air conditioning system, lubrication system, safety valve and control system. The whole machine is installed in a box, which is self-contained and can be directly placed on a flat concrete floor without anchoring bolts on the foundation. The screw head is a two-shaft positive displacement rotary compressor head. A pair of high-precision main (male) and auxiliary (female) rotors are installed horizontally and parallelly inside the casing. The main (male) rotor has 5 teeth, and the auxiliary (female) rotor has 6 teeth. The main rotor has a large diameter and the auxiliary rotor has a small diameter. The teeth form a spiral shape, and the two mesh with each other. Both ends of the main and auxiliary rotors are respectively supported and positioned by bearings. When working, the motor directly drives the main rotor through the coupling (or belt). Since the two rotors mesh with each other, the main rotor directly drives the auxiliary rotor to rotate together. The cooling liquid is directly sprayed into the meshing part of the rotor from the nozzle at the lower part of the compressor casing, and mixed with the air to take away the heat generated by compression to achieve the cooling effect. At the same time, a liquid film is formed to prevent direct metal-to-metal contact between the rotors and close the gap between the rotors and the casing. The injected coolant can also reduce the noise generated by high-speed compression.

The main components of 　　 screw air compressor are screw head and oil-gas separation barrel. The screw head is sucked in through the suction filter and the air intake control valve. At the same time, oil is injected into the air compression chamber to cool and seal the head and lubricate the screw and bearings. The compression chamber generates compressed air. The oil and gas mixture generated after compression is discharged into the oil and gas separation barrel. Due to the action of mechanical centrifugal force and gravity, most of the oil is separated from the oil and gas mixture. The air passes through the oil-gas separation cylinder core made of borosilicate glass fiber, and almost all the oil mist is separated. The oil separated from the oil and gas separation barrel core is returned to the screw head through the oil return pipe. An oil filter is installed on the oil return pipe. After the return oil is filtered by the oil filter, the clean oil flows back into the screw head. After the oil is separated, the compressed air leaves the oil and gas cylinder through the pressure control valve and enters the aftercooler. The aftercooler cools the compressed air and discharges it to the air storage tank for use by various air users. The condensed water is concentrated in the air storage tank and drained through an automatic drain or manually.

　　 Features

　　 1. Piston-type oil-free lubrication air compressor

　　The piston ring in the cylinder of the oil-free air compressor and the packing in the packing device adopt self-lubricating filled PTFE as the sealing element. Therefore, the cylinder and the packing device do not need to be lubricated with lubricating oil, and the compressed gas is basically pure and free of oil under normal circumstances, and there is no need to add an oil removal device. The disadvantage of this machine is 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 workload is large, and the maintenance cost is high.

　　2, screw air compressor

　　 The precise fit between the female and male rotors of the screw air compressor, as well as the rotor and the casing of the machine body, reduces gas return leakage and improves efficiency; only the meshing of the rotors, without the reciprocating movement of the cylinder, reduces the source of vibration and noise. The unique lubrication method has the following advantages. With its own pressure difference, it continuously injects coolant into the compression chamber and the bearing, which simplifies the complicated mechanical structure; the injection of coolant can form a liquid film between the rotors, and the auxiliary rotor can be directly Driven by the main rotor, there is no need to resort to high-precision synchronous gears; the injected coolant can increase the air-tight effect, reduce the noise generated by high-frequency compression, and can also absorb a large amount of compression heat. Therefore, the single-stage compression ratio is even Up to 16 can also prevent the exhaust temperature from being too high, and there will be no friction between the rotor and the casing due to the difference in thermal expansion coefficient. Therefore, the screw air compressor has the advantages of low vibration, no need to fix the foundation with anchor bolts, low motor power, low noise, high efficiency, stable exhaust pressure, and no wearing parts. The disadvantage of this machine is that the compressed air contains oil, and its oil content is 1 to 3×10-6. The process that requires strict oil content in compressed air requires an oil removal device. The plant's compressed air system adds a two-stage oil removal device. Since the compressed air in the ADC process directly contacts the product ADC foaming agent, the air quality requirements are even higher. A three-stage degreasing device is added for the air used in the ADC process. The comparison of compressor performance parameters is shown in Table 1.

　　Main failure

　　 1. Piston-type oil-free lubrication air compressor

　　The piston ring and packing device of this machine do not need to be lubricated with oil. Under normal circumstances, the compressed gas is basically pure and oil-free, but because the oil scraper ring often scrapes the oil incompletely and the seal is not good, the oil often runs to the packing device and even the piston ring, so that the compressed gas contains oil. In addition, the exhaust temperature is high, sometimes as high as 200°C; the cooler is blocked, which makes the cooling effect poor; the piston ring is stained with oil, which is particularly easy to wear; the valve flap is leaking; the cylinder liner is worn and so on.

　　2, screw air compressor

There are few failures of screw air compressors. As long as the oil and gas separator, air and oil filters are regularly maintained, normal operation can be ensured. The maintenance of the two 10m3 screw compressors used was the blockage of the sewage pipe and the failure of the control panel. The host system has been operating normally for 2 years.

　　 Bones oil-free air compressors provide you with 100% oil-free water-lubricated air compressors.