JOHNSON CONTROLS
52
FORM 160.67-O2
ISSUE DATE: 10/9/2020
SECTION 3 - SYSTEM COMPONENTS DESCRIPTION
COMPRESSOR OIL PUMP
The compressor oil pump operation is automatically
controlled from the panel. On startup this pump is
started automatically before the turbine is energized
to establish positive lubrication and sufficient oil pres-
sure. For normal operation the compressor oil pump
should operate at all times during chiller operation. On
shutdown of the system for any reason, (except power
failure) the compressor oil pump will continue to run
until 35 seconds after the turbine has coasted to a stop.
The submerged oil pump takes suction from the sur-
rounding oil and discharges it to the oil cooler where
heat is rejected. The oil flows from the oil cooler to
the oil filter. The oil leaves the filter and flows to the
emergency oil reservoir where it is distributed to the
compressor bearings. The oil lubricates the compressor
rotating components and is returned to the oil sump.
There is an emergency oil reservoir located at the high-
est point in the lubrication system internally in the
compressor. It provides a gravity fed oil supply to the
various bearings and gears in the event of a system
shutdown due to power failure. The reservoir, locat-
ed on the top of the compressor, allows the oil to be
distributed through the passages by gravity flow, thus
providing necessary lubrication during the compressor
coastdown.
COMPRESSOR OIL HEATER
During long idle periods, the oil in the compressor oil
reservoir tends to absorb as much refrigerant as it can
hold, depending upon the temperature of the oil and
the pressure in the reservoir. As the oil temperature is
lowered, the amount of refrigerant absorbed will be
increased. If the quantity of refrigerant in the oil be-
comes excessive, violent oil foaming will result as the
pressure within the system is lowered on starting. This
foaming is caused by refrigerant boiling out of the oil
as the pressure is lowered. If this foam reaches the oil
pump suction, the bearing oil pressure will fluctuate
with possible temporary loss of lubrication, causing
the oil pressure safety cutout to actuate and stop the
system.
The oil heater is automatically controlled
by the control panel at all times during
shutdown, slow roll and ramp up to rated
speed to maintain the oil temperature in
the oil reservoir at a target value which
is 50°F above the condenser refrigerant
saturation temperature. It is turned on
at 4°F below the target value and o at
3°F above the target value. To prevent
overheating the oil, the heater has an
integral thermostat that opens at 180ºF.
The Heater is disabled when "SYSTEM
RUN" is displayed.
STEAM TURBINE
The steam turbine is a high efficiency multistage de-
sign operating at a nominal 4500 rpm design maximum
speed.
The turbine is packaged on a driveline base, complete-
ly factory piped. The driveline base has a mating flange
on shaft end of the package that will bolt directly to the
compressor D-flange face providing a rigid interface
between turbine package and compressor. Complete
turbine/compressor driveline is factory aligned prior
to shipment. Turbine drive shaft is directly connected
to the compressor shaft with a flexible disc coupling.
Coupling is of an all metal construction with no wear-
ing parts assuring long life and no lubrication require-
ments providing low maintenance.
The turbine casing is horizontally split designed to al-
low longitudinal thermal expansion without the affect-
ing alignment or efficiency of the turbine. The shaft
and wheels are alloy steel with the wheels shrunk and
keyed to the shaft. The turbine blades are 403 grade
stainless steel and the shaft is ground throughout with
stainless steel sprayed in the carbon ring end gland
contact area. Stainless steel nozzles are furnished
throughout the turbine. Carbon ring end gland and dia-
phragm seals are furnished. Turbine end gland carbon
ring seals (minimum five seals per end gland) are sepa-
rated by partitions of stainless steel.
A stainless steel, inlet steam strainer with adequate size
and mesh to minimize the pressure drop is supplied.
Strainer is removable without breaking the steam pip-
ing connections.
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