17
Oil Reclaim System — The oil reclaim system recovers
oil from the cooler, removes the refrigerant, filters and returns
the oil back to the compressor. One or more oil reclaim nozzles
are positioned along the length of the cooler to draw the oil and
refrigerant mixture from the surface of the refrigerant level.
The mixture passes through an oil reclaim modulating valve
and into the vaporizer. The flow of refrigerant and oil is regu-
lated to prevent the vaporizer from becoming overloaded with
liquid refrigerant. The modulating valve position is adjusted in
accordance with the difference between the VAPORIZER
TEMP and the EVAP REFRIG LIQUID TEMP. The 4 to
20 mA signal from CCM terminals J8-3 and J8-4 is converted
into a 0 to 10V DC input to the oil reclaim modulating valve by
a 500-ohm resistor connected between CCM terminals J8-3
and J8-4. The oil reclaim modulating valve closes when the
chiller is shut down to prevent the vaporizer and oil sump from
being flooded with refrigerant. Do not manually open the oil
reclaim modulating valve when the chiller is shut down. Doing
so will severely degrade the viscosity of the oil in the sump.
Flow of refrigerant and oil from the cooler can be observed
through a sight glass on top of the vaporizer.
The viscosity of the compressor oil is significantly reduced
when it absorbs refrigerant. A combination of heat and low
pressure is used to vaporize the refrigerant that has been
absorbed by the oil mixture reclaimed from the cooler.
Condenser gas is used to warm the refrigerant and oil mixture
in the vaporizer. Warm refrigerant is bled from the top of the
condenser, directed through a row of tubes that line the bottom
of the vaporizer, and discharged into the cooler. A 1500 W
surface mounted electric heater provides supplemental heat to
the vaporizer when the compressor is operating at lower loads.
Refrigerant boiled out of the reclaimed mixture is vented to the
compressor suction. The concentrated oil mixture drains out of
the vaporizer, through a sight glass, past the vaporizer tempera-
ture sensor, and into the oil sump. (An orifice located between
the vaporizer and oil sump maintains the liquid level in the va-
porizer.) Additionally the oil sump heater maintains the tem-
perature of the reclaimed oil and the oil returned from the com-
pressor at approximately 90 F (32.2 C) when the chiller is run-
ning and 140 F (60 C) when the chiller is off. The oil sump is
also vented to compressor suction to increase oil viscosity by
boiling off additional refrigerant.
ISOLATION
VALVE
CONDENSER
STRAINER
MIST
ELIMINATOR
COOLER
SIGHT GLASS
OIL
HEATER
MIST ELIMINATOR
SERVICE
VALVE
OIL PUMP
ISOLATION
VALVE
PUMP
FILTER
OIL FILTER
ISOLATION
VALVE
ORIFICE
ACTUATED BALL
VALVE
SIGHT GLASS
SIGHT GLASS
VAPORIZER
EXTERNAL OIL HEATER
ISOLATION
VALVE
COMPRESSOR OIL
DRAIN
TO COMPRESSOR
SUCTION
COMPRESSOR
OIL SUPPLY
PRESSURE
REGULATOR
VALVE
OIL
SUMP
Fig. 14 — Oil Flow Schematic
OIL REFRIGERANT OIL/REFRIGERANT MIXTURE
A23-1643
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