Scotsman SCE170 - Manual (Page 17)

Refrigeration Schematic:
Freeze Cycle:
From the compressor, hot discharge gas is
pumped to the condenser, either air or water
cooled.
At the condenser, heat from the refrigerant flows
into the cooling medium, either air or water, and
the refrigerant condenses into a liquid. From the
condenser the liquid refrigerant flows through the
liquid line to the metering device - a thermostatic
expansion valve.
At the externally equalized thermostatic expansion
valve, the liquid refrigerant passes from a high
pressure zone to one of relatively low pressure,
and in the low pressure zone it evaporates. The
low pressure zone where the refrigerant
evaporates is the evaporator. When the refrigerant
evaporates, it absorbs heat from the metal parts of
the evaporator and the water flowing over it.
From the evaporator, the refrigerant flows back to
the compressor through the suction line.
Harvest Cycle:
During the harvest cycle, the refrigerant flows from
the condenser, through the discharge line to a
branch in the line containing the Hot Gas Valve.
This valve is Open during the harvest cycle,
allowing the hot discharge gas to bypass the
condenser and enter the evaporator at its inlet.
The hot discharge gases warm up the evaporator
enough to allow the surface of the ice frozen to the
evaporator to melt. The remaining ice will then fall
off into the bin.
REFRIGERATION SCHEMATIC:
Evaporator
Hot Gas Line
Hot Gas Valve
Suction Line
Liquid Line
Compressor
Fan Motor
Dryer
Condenser
Thermostatic
Expansion
Valve
SCE170
October 1998
Page 17