Technical Parameters of Oil-free Screw Air Type Compressor
| Machine Name | Water injected oil free rotary screw air compressor |
| Compressed Air Status | 100% oil-free |
| Voltage | 380V/50HZ/3P, 220V/50HZ/3P,400V/50HZ/3P, 415V/50HZ/3P, or 60HZ, or custom |
| Working Pressure | Normal pressure: 3 bar, 8 bar, 10bar, (high pressure customizable) |
| Compressor Power | 7.5 KW, 11 KW, 15 KW, 18 KW, 22 KW to 250 KW |
| Air Delivery | 0.8m³/min to 40m³/min @10 bar |
| Air Compressor Noise | 60dB(A) to 85dB(A) |
| Type of Driving | Direct driven |
| Type of Cooling | Air-cooled or water-cooled |
| Sanitary Material | 304 stainless airend, piping and tank |
| Compressor Airend | Single-screw airend |
| Application: | Pharmaceutical, Food, Medical, Beverage, Oxygen&Nitrogon, Precision machine tools |
Features of Water Injected Screw Compressor
(1) High Efficiency
Lubricating water can absorb a lot of the heat of compression. So it improves compression efficiency. Besides, water can achieve air tightness. Thus, the efficiency of oil-free screw compressor is high. It’s better than general dry screw compressors. In addition, the specific heat of water is large. The working process is similar to isothermal compression. Theoretically, there is no clearance volume. The compression chamber temperature can be lowered to close to the intake temperature. So it can reduce the workload of refrigerated air dryers.
(2) Low Noise
The motor is directly connected to the screw. So there is no intermediate transmission gear. In addition, lubricant water can also reduce the noise caused by high-frequency compression. Moreover, the oilless screw compressor has a superior power balance system. It can effectively restrain the vibration source.
(3) Oil-free Compressed Air
The water-injected compressor is a common oil-free screw air compressor. It doesn’t use the lubricant oil. So compressed air is 100% free of any oil. Furthermore, the drained water is also oil-free. So no need for special treatment. It meets environmental requirements.
Why Choose The Lingyu Oilless Screw Type Compressor?
(1) Long Lifetime Full 304 Stainless Steel Single-screw Airend
Oil-free airend adopts PEEK rotor. The rotor and other components are all 304 stainless steel. So ensure that the air oil content is grade 0. Our airend production process comes from Japan. Besides, we use original SKF bearings.
The compression volume ratio of our oil-free screw air compressor is ≥ 95%. The design service life is 15 years. It can run continuously 24 hours a day. Moreover, the structure is good. Thus the vibration is small.
There are two-star wheels on both sides of the screw. So water injected screw compressor has no unbalanced inertial force. And the axial force and radial force on the screw also cancel each other out.
(2) Completely Oil-free Air Quality
Oil-free screw compressor replaces oil with water. So there are 4 major benefits, that is lubrication, cooling, sealing, and noise reduction. It can provide high-quality 100% oil-free air. No pollution. The discharged water also does not need special treatment. It is an ideal isothermal compression due to the action of water. Compared with a dry oil-free compressor, the air volume increases by 15%.
(3) Superior Electrical Control System
Each air compressor has a microcomputer control system. Moreover, it’s with self-diagnosis and protection functions. The panel can display the actual operation of water injected screw compressor.
If the compressor fails, the system will respond accordingly. So the user can replace parts in time. With 485 interfaces, it has a remote control. Therefore, it guarantees safe operation 24 hours a day.
(4) Energy Saving
40,000 hours working without failure, free maintenance, high starting torque, and direct drive.
(5) 304 Stainless Steel Air And Water Separation Tank
The separation tank and piping also use the SS304. So there will be no corrosion.
(6) Pure Copper Radiator
The air-cooled oil-free screw air compressor uses a copper radiator. So the heat dissipation is stable and efficient. And it is with a silent fan.
(7) Power-saving Air Capacity Adjustment
When the air consumption decreases, the system pressure starts to increase. The controller receives the signal. It begins to gradually reduce the opening of the intake valve. At this time, the airflow volume of the oil-free screw air compressor will also decrease. Of course, the motor current will also drop. Conversely, when the gas consumption increases, the system pressure begins to drop. The opening of the intake valve will increase. At this time, the airflow of water injected screw compressor will also increase.
How Does Water Injected Oil Free Rotary Screw Air Compressor Work?
Its working principle is different from that of dry oil-free air compressors. Water injected compressor has only one screw.
The screw and the two-star wheels form a meshing pair. Usually, there are six grooves on the screw. Each of the star gear teeth will mesh with it. The screw groove has upper and lower spaces. Each realizes the working process of the compressor. Oil-free screw compressor generates pressure. During compression, there will inject lubricating water into the compressor chamber.
When working, there is pure water spray cooling between the rotors. Thereby cleaning the air. At the same time, the rotor and pure water will form a good water film seal. Make the system efficiency more than 95%. Therefore, it can realize full energy savings.
The airend compress the water-air mixture. Then enter the stainless steel water air separator. Mechanically separate them into compressed air and pure water. The system temperature is below 45℃. So the water content of compressed air is less than 80g/m³.
Compressed air will be on top of the separator. They pass through the minimum pressure valve and into the vent. Then it will be discharged. Purified water is at the bottom of the separator. The filter will remove impurities in the water. After cooling, the water enters the water-injected screw compressor again. So it starts a second compression cycle. The oil-free screw air compressor can realize automatic water exchange. Therefore, it reduces labor intensity.
Water Injected Oil-free Screw Compressor Maintenance
① When it needs to stop for a long time, check whether the machine circuit is normal. At the same time, drain the lubricating water in the system. Also, close all openings of the oilless screw air compressor. In order to prevent moisture, dust intrusion, and rust.
② The water-injected screw compressor is not used for some time. When restarting the machine, add lubricant water to the separator first. Add until the middle water level. Then open the compressor airend. Manually add purified water to the middle level of the airend. In addition, manually rotate the air compressor several times. Prevent the airend from burning due to lack of water when starting.
③ When the temperature is lower than 0℃, should stop the oil-free rotary screw air compressor, and drain the water in the system. Otherwise, if it freezes, it will damage the airend.
④ Compressor filter maintenance:
First-time maintenance: exchange the air filter and water filter when 200~800 hours.
Regular maintenance: replace the filters every 2000~3000 hours.
Airend maintenance: every two years.
Oil-free Rotary Screw Air Compressor vs Oil-injected Screw Compressor
(1) Higher Compressed Air Quality
Firstly, oilless screw air compressors produce 100% oil-free air. This advantage is obvious. Another point cannot be ignored. The temperature of the water-lubricated air compressor system can reach 45°C. This is lower than that of an oil-injected screw compressor. So the air moisture content will also be lower.
So cleaner air is better for the dryer behind. It can reduce the working load of the dryers, and increase the water removal performance. Also, reduces the corrosion of the refrigeration dryer pipeline. In addition, it can also increase the service life of desiccant dryer adsorbent.
(2) More Energy Saving
This is because of lower air loss. For the latter, it needs to remove the oil in the air. So need to add the corresponding filter. Eventually, it will increase pressure loss. But we must meet the final air pressure. Therefore, the discharge pressure of the latter must be higher than that of an oil-free screw air compressor. The exhaust pressure of the oilless screw compressor is 1.5 bar lower than the latter. The energy consumption is 10% lower. Therefore, the electricity bill of the oil-free compressor is lower.
(3) Lower Maintenance Cost
This is because of lower air loss. For the latter, it needs to remove the oil in the air. So need to add the corresponding filter. Eventually, it will increase pressure loss. But we must meet the final air pressure. Therefore, the discharge pressure of the latter must be higher than that of an oil-free screw air compressor. The exhaust pressure of the oilless screw compressor is 1.5 bar lower than the latter. The energy consumption is 10% lower. Therefore, the electricity bill of the oil-free compressor is lower.
| 20m³/min Oil Injected Rotary Screw Compressor |
20m³/min Water Injected Screw Compressor |
||
| Replace lubricant oil 3 times/year | 120 L * 40 CNY / L * 3 Times = 14400 CNY |
Change water 100 hours/time | 120 L*80 Times/1000*4=38.4 CNY |
| Change the oil separator filter 3 times/year |
(2600+1400)*3=12000 CNY | No | / |
| Replace oil filter 3 times/year | 320*3=960 CNY | Change the water filter 1000 hours/time (subject to the differential pressure alarm) |
8*170*7=9520 CNY |
| Change the air filter 3 times/year | 300*3=900 CNY | Also replace the air filter 3 times/year | 1000*3=3000 CNY |
| Replace the element for the compressed air filter 2pcs/year |
3000*2=6000 CNY | Water softener 3 years/time | 3000 CNY/3=1000 CNY (allocation calculation) |
| 1 year maintenance cost of oil injected screw compressor |
34，260 CNY/year | 1 year maintenance cost of oil free screw air compressor |
13673.6 CNY/year |
To sum up, the maintenance cost of oil-free water-lubricated air compressors is lower.
FAQs
(1) Is the water content in the air larger than other air compressors?
The water-injected screw compressor is an isothermal compression. The discharge temperature is around 45℃. The production of gaseous water is conditional. That is, needs to heat up to above 65 ℃. Therefore, there is also no vaporous water.
Generally, the compressed air has no liquid water. The determining factor of its water content comes from the water-air separation system. In summary, there is no gaseous water in the compressor. Liquid water can also be completely separated.
The water content of our oil-free screw compressor is 15% lower than that of ambient air. It’s lower water content than the oil-injected screw type. Besides, every oil-free machine will be tested by a professional dew point meter. The water content is qualified before leaving the factory.
(2) Is the oil-free water-lubricated airend like a natural “bacteria ship”? Is the exhaust air high in bacteria?
There are preconditions for the growth of bacteria in water. That is, stay in a sealed space for more than 72 hours. But the water in the oil-free screw air compressor is always circulating.
Part of the water is automatically drained every 200 hours. At the same time, it will add some water. Water can wash away germs and dust. Moreover, the filter can also remove some bacteria. Therefore, compressed air contains very few bacteria.
In addition, the intake valve and pressure valve are all sealed. The water inside cannot be in contact with the air at all. So there are no conditions that could breed bacteria. Of course, sometimes we have extreme air quality requirements. In this case, it can add an anti-bacterial filter.
(3) Will the oil-free water-injected screw compressor consume a lot of water?
You don’t need to keep adding water to the air compressor. It’s like a washing machine. There is a water level sensor inside. It can drain and supply water automatically.
For example, there is a 110KW water-injected screw compressor. The amount of lubricant water is 130 liters. A year is calculated as 8000 hours. It needs to exchange 6000 liters of water. That is 6 tons of water. Even if doubled, that is 12 tons. 5 CNY per ton of water. The annual water bill is only 60 CNY. So it saves water and money.
(4) Does water lubricate well? Does the air compressor have a long service life?
Firstly, water has several roles in oil-free screw air compressors. That is, cooling, sealing, and lubricating. Secondly, we usually use SUS304 material in the airend and system of water-injected screw compressor. Its stability has been tested by the market.
In terms of air quality, it’s pure oil-free. Energy saving is high. So prove its advanced technical quality.
In addition, its structure is perfect. This results in its fully symmetrical balanced compression. It vibrates less and the noise is lower. Bearing service life can reach 70,000 to 100,000 hours. So it will not affect the normal use of the whole compressor. The design life of our water-lubricated screw compressor is 25 years. And it can run continuously 24 hours a day.
