Principle Of Operation - How It Works; Ice Maker - Scotsman MAR 78 Service Manual

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1. ICE MAKER

The revolving drum which may be of two different
sizes depending on the ice maker capacity, is
basically made of a cylinder skeleton covered by
a stainless steel jacket.
There is a channel, about 15 m/m deep and 15 m/m
wide on the surface of the cylinder skeleton
which, in a spiral pattern, goes from one end to
the other of cylinder.
Both the ends of the channel communicate with
a bore made in the left cylinder journal. The head
manifold on the left side is for either liquid
refrigerant inlet and vapor refrigerant outlet.
When a cylinder stainless steel jacket is forced
and sealed on the drum, 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
head manifold in the left side cylinder journal,
boils and evaporatores as it comes into contact
with the drum metal jacket. About one third of 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.
1. Water drawing area
2. Water sprayed freezing cooling area
3. Sub-cooling area
4. Float valve
5. Water feeding line
6. Scraping blade
7. Water pump
8. Water basin
9. Revolving drum
10. Water distributor tube
SECTION IV
PRINCIPLES OF OPERATIONS - HOW IT WORKS
2. PRINCIPLES OF OPERATION - HOW IT WORKS
On fresh water installation a combination of water
pump and water distributor tube provides a
constant flow of cold water to the upper side of
the evaporator drum so to have an extended
metal jacket surface covered by water and a
thicker ice layer.
Then 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 peel 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 inner
bore of the left side cylinder journal.
The refrigerant sealing in inlet/outlet head
manifold is assured by specially designed sealing
device, the cylinder is driven by separate drive
motor and gear reducer located on the right basin
frame.
The gear reducer, the driving belt with its pulley,
the revolving drum with the rotating part of the
sealing devices and the water pump on fresh
water installation are the mechanical parts in
motion.
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