Air Compressor Lubricants
Lubrication is very necessary in the gears, piston and valves of air compressors so that they can operate smoothly and reduce the effects of harsh friction.
Regular lubrication improves an air compressor's life and functioning.
All oiled compressors require lubrication and oil-free ones need them only for some gears and parts outside the cylinders.
The lubricant oil gets mixed up with the passing air flow and compressed air filters are employed to separate them out.
Generally synthetic oils, petrochemical refinery produced mineral oils and a few natural oils are used as lubricants.
Three types of synthetic oil are very common as air-line lubricants; these are Fluorosilicones, Di-ester based and Phosphate ester based oils.
Mineral oil based lubricants are categorized according to viscosity index (VI) as defined by Society of Automotive Engineers (SAE).
There are five groups (Group I- group IV) having separate VI, different quantity of saturates and amount of sulphur.
Manufacturers incorporate various additives to enhance lubricating quality reduce oxidation of end product lubricant when applied in compressors.
Selection of these additives is very important and varies in different VI levels.
Use of naturally obtained oils as lubricant is less than the other two groups and these are mainly triglyceride esters obtained from plant and animal sources.
These were liquid lubricants for oiled air compressor.
Oil-free compressors do not need oil-lubrication as they contain a PFTE or Teflon non-stick coating which acts as permanent solid lubricant and withstand high temperatures as 350°C.
However at very high pressure ceramic or alloy metal coating is used as solid lubricant.
Oiled compressors come with sufficient lubrication from the factory but throughout lifetime they need lubricants at regular intervals.
The lubricant dispensing unit is an air-line lubricator and is installed at the end of FRL arrangement (Filter/Regulator/Lubricator) in the line of an air compressor.
The air passing through this line will carry oil with it to the cylinder.
This is filtered later.
The lubricator has four parts-an adjusting screw housed on lubricator head which is main part (through the head air flow is pressurized and lubricator oil is fractioned into finest droplets), lubricator bowl containing oil and a drain.
Air compressor lubricant oils have some special properties.
They should be non-detergent oil, free from impurities, should not produce sludge, should be non-inflammable, non-reacting, stable at high temperature and pressure, and their viscosity should be appropriate as required by the specific application of air compressor.
Continental Oil Company, Clark Oil and Chemical Company, Texaco Inc.
, Century, Mobil, Shell, Duckhams, Esso, Castrol and Dow Corning are some famous manufacturers of oil for air compressor lubricants.
Regular lubrication improves an air compressor's life and functioning.
All oiled compressors require lubrication and oil-free ones need them only for some gears and parts outside the cylinders.
The lubricant oil gets mixed up with the passing air flow and compressed air filters are employed to separate them out.
Generally synthetic oils, petrochemical refinery produced mineral oils and a few natural oils are used as lubricants.
Three types of synthetic oil are very common as air-line lubricants; these are Fluorosilicones, Di-ester based and Phosphate ester based oils.
Mineral oil based lubricants are categorized according to viscosity index (VI) as defined by Society of Automotive Engineers (SAE).
There are five groups (Group I- group IV) having separate VI, different quantity of saturates and amount of sulphur.
Manufacturers incorporate various additives to enhance lubricating quality reduce oxidation of end product lubricant when applied in compressors.
Selection of these additives is very important and varies in different VI levels.
Use of naturally obtained oils as lubricant is less than the other two groups and these are mainly triglyceride esters obtained from plant and animal sources.
These were liquid lubricants for oiled air compressor.
Oil-free compressors do not need oil-lubrication as they contain a PFTE or Teflon non-stick coating which acts as permanent solid lubricant and withstand high temperatures as 350°C.
However at very high pressure ceramic or alloy metal coating is used as solid lubricant.
Oiled compressors come with sufficient lubrication from the factory but throughout lifetime they need lubricants at regular intervals.
The lubricant dispensing unit is an air-line lubricator and is installed at the end of FRL arrangement (Filter/Regulator/Lubricator) in the line of an air compressor.
The air passing through this line will carry oil with it to the cylinder.
This is filtered later.
The lubricator has four parts-an adjusting screw housed on lubricator head which is main part (through the head air flow is pressurized and lubricator oil is fractioned into finest droplets), lubricator bowl containing oil and a drain.
Air compressor lubricant oils have some special properties.
They should be non-detergent oil, free from impurities, should not produce sludge, should be non-inflammable, non-reacting, stable at high temperature and pressure, and their viscosity should be appropriate as required by the specific application of air compressor.
Continental Oil Company, Clark Oil and Chemical Company, Texaco Inc.
, Century, Mobil, Shell, Duckhams, Esso, Castrol and Dow Corning are some famous manufacturers of oil for air compressor lubricants.
Source...