Emerson Copeland Screw SCA2, Applications Manual, Page: 6 / 22

AE4-1322
© 2002 Copeland Corporation
Issued 4-2002
Printed in U.S.A.
6
2.8 Oil circulation 2.8 Oil circulation 2.8 Oil circulation 2.8 Oil circulation 2.8 Oil circulation
The lubrication circuit is designed as is typical for
screw compressors. This type of design, however, has
a vessel directly flanged-on to the compressor housing
at the high-pressure side. It contains the oil reservoir.
The vessel simultaneously serves as an oil separator.
The oil circulation results from the pressure difference
to the oil injection point, where the pressure level is
slightly above suction pressure. The oil flows through a
generously sized filter element to the throttle point and
subsequently to the bearing chambers and the profile
spaces of the rotors. The oil is then transported
together with the refrigerant vapor in the direction of
compression. In addition to lubrication it also provides
a dynamic seal between the rotors and between the
housing and the rotors. The oil then flows together with
the compressed vapor into the reservoir vessel. Here oil
and vapor are separated in a highly efficient process.
The oil collects in the lower part of the separator vessel
and flows back into the compressor either direct or via
an external oil cooler. Depending on the operating
conditions the circulating oil must be cooled with liquid
injection or an external oil cooler (see Section 4.4 and
4.5)
Monitor the oil circuit Monitor the oil circuit Monitor the oil circuit Monitor the oil circuit Monitor the oil circuit
• For short circuits without without
without without
without refrigerant injection for
additional cooling and for small system volumes
and refrigerant charges: indirect monitoring by
means of oil temperature protection (standard)
CAUTION! CAUTION!
CAUTION! CAUTION!
CAUTION!
Lack of oil leads to a dramatic Lack of oil leads to a dramatic
Lack of oil leads to a dramatic Lack of oil leads to a dramatic Lack of oil leads to a dramatic
temperature increase. temperature increase. temperature increase. temperature increase. temperature increase.
Figure 4
Infinite capcity control scheme