Technical data

In the first stage of oil separation, high velocity oil and
refrigerant gas in the compressor discharge line
undergoes a rapid reduction in velocity as it enters the
large diameter oil separator. Most of the oil drops out of
the refrigerant gas stream due to the reduction in
velocity. The oil falls by gravity into the oil reservoir
located in the bottom of the oil separator.
The second stage of oil separation is achieved in the oil
coalescing element section of the oil separator. The oil
mixed with the refrigerant entering the coalescer
element is a very fine aerosol mist. These small aerosol
mist particles wet the coalescer element media and form
larger oil droplets which fall by gravity to the bottom of
the coalescer element section. The oil collected in the
coalescer section is drained from the oil separator with a
small amount of refrigerant gas. This provides the high
pressure “gas drive” for the eductors to return oil from
the evaporator.
The oil separator has a design working pressure of
16.2 bar. Two sight glasses are provided in the oil
separator for monitoring the oil level and verifying
performance of the coalescer element. Liquid oil should
be visible in the top glass of the oil separator when the
chiller is off. During operation, oil may be higher or lower
due to system load and operating conditions.
An oil drain and charging valve is located on the bottom
of the oil separator. A 5/8 inch male flare connection is
provided for draining and charging.Oil can be added into
the oil reservoir with the chiller in service.
A temperature actuated immersion oil heater is located
in the oil separator reservoir. Power wiring is provided to
the control panel.
2.6 Oil Filter
The oil flows from the oil separator through the 3 micron
oil filter. Filtered oil then flows to an oil manifold that is
located at the compressor.
A dual oil filter housing with isolation valves is optional
on all units. This allows switching between two 3 micron
oil filters and changing of the off line filter during
operation.
2.7 Oil Eductor Circuit
The oil eductor circuit automatically recovers any oil that
may migrate to the evaporator and returns it to the
compressor.The oil eductor circuit manages the amount
of oil in the refrigerant charge. A small amount of oil is
normal in the refrigerant charge and will be found in the
evaporator. If not properly managed the oil will
accumulate and have an adverse affect on unit
performance.
The oil eductor circuit consists of two refrigerant/oil filter
driers, an eductor block and the interconnecting piping.
The eductors operate using the 'jet pump' principle.
Discharge pressure gas and oil flows through a filter
dryer to a regulating orifice and nozzle located in the
eductor block. The reduced pressure (pumping action)
is created by the velocity of the discharge pressure gas
and oil flowing through the orifice and nozzle. This
creates a reduced pressure area that allows the oil-rich
refrigerant and oil to flow from the evaporator into the
compressor.
Oil-rich refrigerant flows into the eductor block through
the filter drier from the evaporator. The oil-rich
refrigerant mixes with the discharge pressure gas and
flows into the compressor.
2.8 Heat Exchangers
Shells
Evaporator and condenser shells are fabricated from
rolled carbon steel plates and have fusion welded
seams. Carbon steel tube sheets, drilled to
accommodate the tubes, are welded to the ends of each
shell. Intermediate tube supports are fabricated of
13 mm thick carbon steel plates. The refrigerant side of
each shell has a design working pressure of 16.2 bar
and is tested at 37.5 barg. Each vessel has a single or
dual refrigerant relief device.
Tubes
Heat exchanger tubes are 19 mm OD copper alloy with a
high efficiency, internally and externally enhanced
design to provide optimum performance. Each tube is
roller expanded into the tube sheets to provide a
leak-proof seal. Each tube is individually replaceable.
160.81-ICOM-GB0 (01/02) 2-3
FILTER
DRIER
FILTER
DRIER
L.I.C.
FILTER DRIER
OIL
EDUCTOR
BLOCK
OIL
CHARGING
VALVE
OIL
FILTER
EVAPORATOR
Figure 2.3 Oil Circuit