JOHNSON CONTROLS
55
SECTION 3 - SYSTEM COMPONENTS DESCRIPTION
FORM 160.67-O2
ISSUE DATE: 10/9/2020
3
KG Steam Turbine with Ring Oil Lubrication
The KG turbine models have an integral ring oil lu
-
brication system built into the turbine. Brass oil rings
running on the turbine shaft pick up oil from the res-
ervoirs in the two bearing housings. As the shaft and
rings rotate together, oil flows from the oil rings onto
the shaft and ultimately into the bearings providing lu-
brication. The oil level in the bearing housing must be
maintained at a sufficient level to allow the oil rings
to run in the oil. An oil level that is too high results
in oil leakage past the shaft seals. Oil rings cease to
rotate sufficiently fast below 900 RPM to assure ad
-
equate lubrication. During startup, the automatic con-
trols will shut the turbine down if the turbine does not
achieve 1200 RPM within 100 seconds after the start
is initiated, the turbine trip solenoid is energized, and
rotation begins. See the
of this manual for more details. The
turbine does not have an oil pump, oil filter, external
oil cooler, or an external oil reservoir. There are two
bearing housings which are located on each end of the
turbine shaft outboard of the gland seals. Bearing hous-
ings on the KG turbine are directly cooled with water.
It is important that the valve in the cooling water outlet
line be adjusted so that the temperature of the oil in the
bearing housings does not drop below 130°F (54°C).
Cooling water must be supplied at 2 GPM (7.0 L/
min) minimum, 90
°
F (32
°
C) maximum, and 150 PSIG
(1035 kPaG) for the bearing housings.
Do not allow the COOLING WATER
to COOL THE BEARING OIL SUMP
TEMPERATURE to below 130°F (54°C),
as this may interfere with the action of the
oil rings or cause atmospheric moisture to
condense in the oil reservoir.
The bearing housings are continuously purged during
operation with instrument air that has been reduced in
pressure by a pressure reducing valve. This air purge
helps prevent contaminants such as steam from enter-
ing the bearing housing. The pressure reducing valve
should be checked for maintenance and for outlet pres-
sure from time to time.
KD Steam Turbine with External Pressurized
Lube System
The lubrication system is external but completely fac-
tory assembled into the turbine driveline base. The KD
steam turbines have a shaft mounted main oil pump.
The external lubrication system includes an remote
lube oil reservoir with level gauge, an open motor
driven auxiliary oil pump, (not submersible as on the
compressor oil pump), water cooled shell and tube oil
cooler, (with copper tubes), 25 micron full flow oil fil
-
ter, (dual oil filters available as a price addition). Oil
temperature control is by a three way temperature con-
trol valve. The bearing housings are located on each
end of the turbine shaft outboard of the gland seals.
The bearing housings are continuously purged during
operation with instrument air that has been reduced
in pressure by a pressure reducing valve. This helps
prevent contaminants such as steam from entering the
bearing housing. The pressure reducing valve should
be checked for maintenance and for outlet pressure
from time to time.
KD Turbine Auxiliary Oil Pump
On startup, the KD turbine auxiliary oil pump is started
automatically before the turbine is rotated and prior to
the start of the compressor oil pump. After the turbine
has been slow roll and ramped up to above 3000 RPM,
if the turbine shaft driven oil pump is producing suf-
ficient pressure above the set point of the auxiliary
oil pump control logic, the auxiliary oil pump will be
stopped. On shutdown for any reason, (except power
failure) the auxiliary oil pump will be energized when
the turbine slows to 3000 RPM and will continue to
run until 30 minutes after the turbine has come to rest
to remove excess heat from the bearings.
Turbine Gland Seal System
Gland seals are provided on both the high pressure in
-
let end and low pressure outlet end of the steam turbine
to minimize the leakage of steam from the turbine or
prevent the leakage of air into the turbine. The inlet
steam pressure for standard YST turbines can be from
90 to 200 psig depending on the design for the particu
-
lar job. The outlet steam pressure is below atmospher-
ic, typically in the neighborhood of 1.5 PSIA. A small
flow of steam through the gland seal is maintained to
prevent condensation and a loss of seal in the gland.
Additional details of the standard gland seal systems
as well as those that could be supplied on non-standard
applications such as non-condensing turbines and on
turbines with inlet steam pressures above 200 PSIG are
described in the following paragraphs.
Types of Gland Leak-Off Systems
Steam in non-condensing turbines tends to leak around
the shaft since the pressure in the casing is greater than
atmospheric. Leaks should be limited for the follow-
ing reasons:
