Comparison between dry oil-free screw machine and water-lubricated oil-free screw machine
itemDry oil free screw machineWater lubrication oil free screw machine
ReliabilityThe development and application of dry screw air compressor has a long history and the technical solution is very mature. At present, internationally renowned compressor manufacturers such as Atlas and Ingersoll Rand use dry screw technology to produce pure and oil-free compressed air.Because water only It has a cooling effect and cannot achieve true lubrication. The technical solution is not mature. Therefore, only a few companies have developed small water lubrication models (below 30kw), which cannot be promoted in a wider range, and the performance is unpredictable.
Usage EnvironmentApplicable to any environmentBecause it consumes a lot of water during operation, it is not suitable for use in dry and water-deficient areas, and it is not suitable for cold areas, considering the problem of icing.
Use of pure water resourcesNot requiredThe requirements for water quality are high, need to be replenished regularly, consume a lot of pure water, long-term use is a small expense.
SecurityDo not use water, there is no problem with the introduction of waterWater quality deterioration is likely to cause corrosion and scaling of the compressor mainframe, which may cause problems such as reduced efficiency of the main engine, seizure, etc., and safety accidents caused by water leakage and water leakage are not overlooked
Water filter blockageThis problem does not existInsufficient lubrication and excessive exhaust temperature
Air inlet after shutdown WaterThere is no such problemThe water stop valve seal surface is worn, the water stop valve is not tight, causing the lubricating water to go from the stop. The port is ejected and the compressor is reversed, which may cause mechanical failure of the rotating part of the compressor.
Exhaust AmountThe rotor and compression chamber are wear resistant and corrosion resistant Special material processing and use of secondary compression technology can ensure long-term efficient operation of the compressor, and the exhaust gas is stable for a long time The acidic medium in the air dissolves in the lubricating water and gradually corrodes The screw causes the space between the star wheel and the screw to become larger, and part of the air is not compressed out, but stays in the compression chamber, which reduces the efficiency of the compressor and the displacement is insufficient. In addition, since the space between the star wheel and the screw becomes larger, the lubricating water cannot A water seal is created between the star wheel and the screw, and a part of the compressed air leaks back from the compression chamber to the suction chamber, which also causes a decrease in efficiency and insufficient displacement. The longer the use time, the lower the displacement.
Bearing costsConventional bearings, maintenance replacement costs are not HighThere are few manufacturers producing water-lubricated bearings, the price is relatively expensive, and the maintenance replacement cost is high.
Number of bearingsTwo-axis motion system, requires 8 bearingsThree-axis motion system requires 12 Bearings, increased wear parts and points of failure
LifetimeThe rotor is made of metal, wear-resistant and has a long service lifeThe star wheel is made of non-metallic material, the wear resistance is worse than metal, the failure rate is high, and the service life is short.
Compression efficiencyUsing secondary compression technology, the whole The compression efficiency has been relatively stable during useThe initial compression efficiency is higher, for a while Post-compression efficiency continues to decline,
Market share Dry oil-free screw compressors are the mainstream products, and the annual demand is increasing by an average of 15% or more. is still in the experimental stage, the reliability is poor, and the proportion is very small
SummaryDry oil-free screw machine has a long history of application and longevity Long, less wearing parts, secondary compression technology to ensure long-term stable displacement Water-lubricated oil-free screw machine has a short life, high exhaust gas volume, low performance, unstable performance And because of the high requirements for water quality, there are obvious design flaws, the technical solution is not mature