Icematic N 132M, Service Manual

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GB
15
REFRIGERATION DURING FREEZE:
This ice machine employes either air or water as a
condensing media, the refrigeration system for either
one is a follows:
At the hermetic compressor, Refrigerant is com-
pressed into a high temperature, high pressure gas.
The gas moves through the
discharge
line into the
condenser
, air or water-cooled. If air-cooled, the dis-
charge pressure will change with the heat load and the
ambient air temperature.
If water-cooled, the discharge pressure is controlled by
the amount of water flowing through the
condenser
-
which is determined by the water regulating valve.
After the gas is cooled in the condenser, giving up
much of its heat, the gas condenses into a high pres-
sure liquid. This liquid travels through the
liquid line
to
the metering device, a
thermostatic expansion
valve.
The thermostatic expansion valve meters how much
liquid refrigerant is to be allowed into the evaporator
section of the refrigeration system.
This is determined by the temperature of the TXV
sensing bulb, located on the
suction line
manifold, at
the outlet of the
evaporator.
If the bulb senses a warm suction line, more refriger-
ant is allowed into the evaporator, (common at the
beginning of the freeze cycle) and when the tempera-
ture begins to fall, less refrigerant is allowed through.
This is why the suction side gauge pressure will
decline throughout the freeze cycle. At the evaporator,
the liquid refrigerant released from high pressure, boils
off in the low pressure environment and absorbs heat,
thus cooling the evaporator surface and anything near
it, such as water.
The low pressure refrigerant vapor then is forced
through the heat exchanger where any excess liquid
refrigerant boils-off, allowing only refrigerant vapor to
enter the compressor suction tube, where it is recom-
pressed into high pressure, high temperature gas
again and the cycle repeats.
OPERATION
H E A T
E X C H A N G E R
E V A P O R A T O R
C O N D E N S E R
C O M P R E S S O R
E X P A N S I O N V A L V E
H O T G A S S O L E N O I D V A L V E
A I R O R W A T E R
D R I E R
S T R A I N E R
R E C E I V E R
( W A T E R C O O L E D O N L Y )
L O W P R E S S U R E V A P O R L O W P R E S S U R E L I Q U I D H I G H P R E S S U R E L I Q U I D H I G H P R E S S U R E V A P O R
X
FREEZE CYCLE
REFRIGERATION SYSTEM SCHEMATIC