Compressor
Model
Approximate
Quarts
Capacity
Liters
791, 891
7.0
6.6
Figure 1.6B: Oil capacity chart
Acceptable Crankcase Oil Products for Corken
Compressors
Constant Weight - Non-Detergent - R&O Inhibited
Oil product
ISO
VI
SAE
Ambient Temp.
Exxon®
TERESSTIC
100
95
30
65° - 100° F
68
95
20+
45° - 70° F
46
95
20
35° - 50° F
Mobil®
RARUS 427 Reciprocating
100
95
30
65° - 100° F
Compressor Oil
DTE Oil Heavy Medium
64
95
20+
45° - 100° F
Dectol R&O Oil
44
95
20
35° - 50° F
Conoco®
Dectol R&O Oil
100
98
30
35° - 50° F
68
97
20+
45° - 70° F
46
99
20
35° - 50° F
Texaco®
Regal R&O Oil
100
92
30
65° - 100° F
68
97
20+
45° - 70° F
46
102
20
35° - 50° F
Sun®
SunVis 900 Oil
100
100
30
65° - 100° F
68
100
20+
45° - 70° F
46
100
20
35° - 50° F
Figure 1.6A: Oil selection chart
Figure 1.7: Distance piece details
Upper
Distance
Piece
Drain Plug
Lower
Distance
Piece
Drain Plug
and from these tapped holes are essential for optimum
compressor performance.
Corrosive gases should be prevented from entering the
crankcase, since even small amounts of gas leakage into
the crankcase can seriously contaminate the crankcase
oil. To prevent this contamination, the distance piece
may be purged, padded, or vented using a clean, non-
corrosive gas like dry air or nitrogen.
Purging:
Purging of the distance piece controls leakage of process
gas to the atmosphere. Process gas leakage into the
distance piece is quickly diluted by the purge gas and
swept away. The purge gas should be vented to a safe
release area, flare, compressor’s inlet, or treatment
facility, depending on the gas and local regulations.
When purging, it is critical to maintain the proper
pressure loading across each set of packing. The higher
pressure should be on the open side of the “V”, which is
also the side with the spring.
Moisture, oil, or condensate can be removed from the
distance piece with the purge gas by using the lower
distance piece connection (drain location) as the purge
gas outlet connection.
Non-detergent oil is recommended for Corken vertical
compressors. Detergent oils tend to keep wear particles
and debris suspended in the oil, whereas non-detergent
oils let them settle in the bottom of the crankcase.
When non-detergent oils are not available, detergent
oils may usually be successfully substituted, although
compressors handling ammonia, amine, or imine gases are
notable exceptions. These gases react with the detergent
and cause the crankcase oil to become corrosive and
contaminated. Figures 1.6A and 1.6B show recommended
oil viscosities and crankcase capacities. Ensure oil is
compatible with the product being compressed.
Synthetic lubricants are generally not necessary. Please
consult your lubricant supplier if you are considering the
use of synthetic oil.
1.7 Purging, Padding, Venting and
Draining of Distance Pieces
The key to leakage control and oil-free operation of
Corken compressors is the distance piece. The distance
piece is integral with the crosshead guide and forms
the upper portion of it. Distance pieces are equipped
with tapped holes to allow purging, padding, venting,
and draining (see Figure 1.7). Proper connections to
7
