Page 139 - Reciprocating Compressors Operation Maintenance

Operation and Maintenance of Reciprocating Compressors 125

COMPRESSOR CYLINDER LUBRICATION OIL SELECTION

Table 3-2 shows the recommended minimum viscosities for various
cylinder diameters and pressures.

TABLE 3-2
RECOMMENDED LUBRICANT VISCOSITIES FOR
RECIPROCATING COMPRESSORS

MINIMUM FLASH: 100* F. MAX. POUR: HIM. GAS SUCTION TEMfERATIHiE PLUS IO*F,
Pr«*sure* MlnimuM Yl»co«lt» 0 JIO'F.
PS 10 Cyl. 01 aim. up to. 10" IO"-I8" I5"-20" 20* t above
0-200 50 SSU 50 SSU 60 SSU 80 SSU
200-1000 60 SSU 80 SSU 80 SSU 80 SSU
1000-2500 80 SSU 80 SSU HO SSU
1SOO-WOO no ssu 110 SSU
"WOO & up ISO SSU ISO SSU
Hydrocarbon Qatei - Use next higher vl*cotlty from table
with mlnlKum vlicoslty of 10 SSU 0 2IO*F.

These values are only given as a guide; different oils of the same vis-
cosity may have different lubricating qualities. Regular examination of
the cylinder bores during the first weeks of operation should be made to
determine if adequate lubrication is being maintained.
The choice of a cylinder lubricant is affected by the properties of the
gas to be handled. In this respect, gases usually fall into one of three
classes: inert, hydrocarbon, and chemically active gases.

Inert Gases

Inert gases that do not tend to condense on the cylinder walls introduce
no special problems and employ the same cylinder lubrication that is
used for air cylinders operating under similar conditions. Examples of
such gases are carbon dioxide, nitrogen, and helium.

Hydrocarbon Gases

Some gases, although dry at the start of compression, tend to condense
on cylinder walls as pressure increases. This is because the temperature at
which a gas can be liquefied by heat removal (i.e., lowering its condens-