Scotsman MAR 106, Service Manual

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SECTION III
PRINCIPLES OF OPERATION - HOW IT WORKS
1. ICE MAKER
The revolving drum which may be of different size
depending on the ice maker capacity, is basically
made of a cylinder skeleton covered by a stainless
steel jacket.
A channel, about 15 m/m deep and 15 m/m wide
is machined in a spiral pattern that goes from one
end to the other of the cylinder skeleton.
The end of the machined channel communicate
with a bore made in the left cylinder journal. The
head manifold on the left side is for both liquid
refrigerant inlet and vapor refrigerant outlet.
When cylinder metal jacket is forced and sealed
on the cylinder skeleton, the spiral pattern channel
made for the refrigerant flow becomes virtually
the evaporator serpentine.
The metered refrigerant that reaches the
evaporator serpentine by passing throught the
bore in the left side cylinder journal, boils and
evaporatores as it comes in contact with the drum
metal jacket. About one third on the cylinder drum
is constantly submerged in water.
This will allow the cylinder metal jacket to draw a
film of water that, as soon as it comes afloat,
freezes almost instantly due to the heat absorption
created by the boiling refrigerant circulating in the
inner serpentine and scrubbing with the jacket
inner surface.
2. PRINCIPLES OF OPERATION - HOW IT WORKS
The ice layer of the emerged cylinder sector has
a fraction of time to solidify, dry and eventually
subcool before contacting the edge of the
horizontal scraping blade.
The scraping blade, of heavy duty metal, cause
the peels off of the ice sheet formed on the drum
jacket by racking it while it advances on the
revolving drum.
The ice sheet is so dry that, when it gets in contact
with the scraping blade, it cracks in a form of
irregular shaped chips. The refrigerant leaves
the evaporator serpentine to return to the
compressor via suction line through the bore of
the head manifold on the left side cylinder.
The refrigerant sealing in the manifold is assured
by an especially designed sealing device.
The cylinder is driven by a separate drive motor
and gear reducer located on the right side.
Four motors are constantly in motion:
a) the compressor
b) the drive motor
c) the fan motor
d) water pump
The gear reducer, the driving belt with its pulley
and the revolving drum with the rotating part of
the sealing devices are the mechanical parts in
motion.
1. Water drawing area
2. Water sprayed freezing cooling area
3. Sub-cooling area
4. Water reservoir float valve
5. Water feeding line
6. Scraping blade
7. Spray bar
8. Water reservoir
9. Revolving drum
10. Water pump
11. Water drain hole