See Table 1.

Introduction concerning duties of compressors

The following guidelines are given to help interested parties in differentiating between

- light duty

- medium duty

- heavy duty

(see also ISO 5388)

Reciprocating oil-lubricated and rotary drip-feed air compressors

Whether the duty of reciprocating and rotary drip feed compressors is to be classified as light, medium, or heavy depends on many parameters, for example

a) the compressor design, i.e., type of cooling, number of stages, valve velocities, oil retention time, etc. ;

b) ambient conditions, i.e., intake "air" temperature, coolant temperature, presence of catalytic dust or gases, etc. ;

c) operating conditions, i.e., continuous or intermittent service, layout of the pressure system, maintenance, oil change intervals, etc.

The ultimate criterion is satisfactory, reliable air compressor operation with the prevention of excessive oil retention or the formation of coke deposits in the hot discharge air system.

Rotary oil-flooded air compressors

Whether the duty of rotary oil-flooded air compressors is to be classified as light, medium, or heavy depends on many parameters, for example

a) the compressor design, i.e., air discharge pressure and pressure ratio, number of stages, oil recirculation rate, oil separating system, etc. ;

b) ambient conditions, i.e., intake air temperature and humidity, presence of contaminants (dust or gases), etc. ;

c) operating conditions, i.e., continuous or intermittent service, maintenance, oil change intervals, discharge temperature, etc.

NOTE - Conditions such as air humidity or low circulating air volume may recommend an oil for heavier duty.

Concept

The lubricants defined by this specification are high quality oils formulated with additives to provide good oxidation resistance, corrosion protection, demulsibility, and foam stability. This specification addresses ester and PAO-type fluids.