Oil Reclaim System; Primary Oil Recovery Mode; Secondary Oil Recovery Method; Bearings - Carrier AquaEdge 19XRV series Operation, Maintenance And Installation Manual

MOTOR
COOLING LINE
TXV BULB
Oil Reclaim System —
oil lost from the compressor housing back to the oil reservoir
by recovering the oil from 2 areas on the chiller. The guide
vane housing is the primary area of recovery. Oil is also recov-
ered by skimming it from the operating refrigerant level in the
cooler vessel.
PRIMARY OIL RECOVERY MODE — Oil is normally re-
covered through the guide vane housing on the chiller. This is
possible because oil is normally entrained with refrigerant in
the chiller. As the compressor pulls the refrigerant up from the
cooler into the guide vane housing to be compressed, the oil
normally drops out at this point and falls to the bottom of the
guide vane housing where it accumulates. Using discharge gas
pressure to power an eductor, the oil is drawn from the housing
and is discharged into the oil reservoir.
SECONDARY OIL RECOVERY METHOD — The sec-
ondary method of oil recovery is significant under light load
conditions, when the refrigerant going up to the compressor
suction does not have enough velocity to bring oil along. Under
these conditions, oil collects in a greater concentration at the
top level of the refrigerant in the cooler. This oil and refrigerant
mixture is skimmed from the side of the cooler and is then
drawn up to the guide vane housing using discharge gas pres-
sure to power an eductor. There is a filter in this line. Because
the guide vane housing pressure is much lower than the cooler
pressure, the refrigerant boils off, leaving the oil behind to be
collected by the primary oil recovery method.
There are three pump-filter configurations. The original
vane pump, in which the oil filter is contained in the pump
housing, followed by the vane pump with the oil filter being
external in the oil piping between the oil pump and the oil cool-
er. The third configuration is the gerotor pump, also with the
external oil filter.
REAR MOTOR
BEARING
REAR HIGH
OIL PRESS
SPD BRG
REGULATOR
OIL FILTER
FLOW
ISOLATION
VALVES
PRESSURE
TRANSDUCER
OIL COOLER
Fig. 7 — Two-Stage Lubrication System
The oil reclaim system returns
FWD MOTOR
BEARING
OIL SUPPLY TO
FORWARD HIGH
SPEED BEARING
OIL PUMP OIL
AND MOTOR
HEATER
EDUCTORS
SIGHT GLASS
A gerotor pump has two rotors, one is inside the other and
their center points are offset with respect to each other. This
type of pump provides a smooth continuous flow. It is also qui-
eter than other designs.
The gerotor pump can be most easily identified by the exter-
nal location of the oil pressure regulator. The regulator is locat-
ed on the bottom of the pump pointing horizontally to the left.
See Fig. 8.
The 19XRV compressor assemblies include
Bearings —
four radial bearings and four thrust bearings. The low speed
shaft assembly is supported by two journal bearings located
between the motor rotor and the bull gear. The bearing closer to
the rotor includes a babbitted thrust face which opposes the
normal axial forces which tend to pull the assembly towards
the transmission. The bearing closer to the bull gear includes a
smaller babbitted thrust face, designed to handle counterthrust
forces.
For Frame 2 19XRV compressors the high speed shaft as-
sembly is supported by two journal bearings located at the
transmission end and mid-span, behind the labyrinth seal. The
transmission side of the midspan bearing also contains a tilting
shoe type thrust bearing which opposes the main axial forces
tending to pull the impeller towards the suction end. The
impeller side face of the midspan bearing includes a babbitted
thrust face, designed to handle counterthrust forces.
For 19XRV Frame 3, Frame 4, Frame 5, and Frame E com-
pressors today (earlier versions had journal bearings), the high
speed shaft assembly has been redesigned to utilize rolling ele-
ment bearings (radial and thrust). Machines employing the roll-
ing element bearings can be expected to have higher oil pres-
sure and thrust bearing temperatures than those compressors
using the alternate bearing design.
12
LABYRINTH
GAS LINE
STRAINERS
SIGHT
GLASS
FILTER
OIL SKIMMER
LINE
COOLER
a19-2050