Wood County reporter. [volume] (Grand Rapids [i.e. Wisconsin Rapids], Wis.) 1857-1923, 1913-02-27
OPERATION Of
ICE MACHINES
By Prof. @. C. Edwards State
University.

Professor o. c. Edwards Of the
Wisconsin University has written the
following. It explains the working
Of an ice machine, how it is operat-
ed and furnishes a great dsaI Of infor
nation regarding the use Of differ
ent gases in the production Of ice
Professor Edwards is an expert on
chis subject and those interested
in knowing something about ice ma
chimes viii find this interesting. Both
the ice machine manufacturers in
this city use the carbonic system.
Any machine designed for ice
making purposes must be based up
on certain fundamental facts. Either
d gas or vapor must be admitted to
a cylinder andscompressed by means
Of piston, then relieve it Of its heat
so as to diminish its volume; next,
cause this compressed gas or yapor
TO expand so as to produce mechani-
cal work, and thus lower it's tempera
ture The heat taken up by the gas
or vapor at this stage, in resuming
its original condition constitutes the
refrigerating effect of the machine.
The useful effect Of an ice machine
depends upon the ratio between the
heat units eliminated and the work
expended in COMPRISING and expand
ing. The ice machine possesses the
greatest efficiency when the range
Of temperature is small, and when
the final temperature is elevated. If
the temperatures, are the same there
IS no advantage in employing gas
rather than a vapor in order to make
ice. The machine using gases as a
rule, to produce a given useful effect
must be of larger dimensions. than
required by iQuifiabEe vapors. The
maximum pressure is determined by
the temperature Of the condenser
md the nature OF the vohtile liquid
)f volume of a saturated vapor is
made under constant pressure, the
remains constant. The
addition or subtraction Of heat which
produces the change of volume is
represented by an increase or de- |
crease Of the quantity of liquid mix
I'd with the vapcr When vapors, e.
ven if saturated, and are no longer |
in contact with their liquids, receive |
an addition of heat either by COM |
preston or by some external source |
Of llrepj, ,hey behave nearly IN the |
same way as permanent gases and ba- |
come superheated 1t is mainly from
this principle that ice machines us |
ing a lquifiable gas will afford re-
suits differing according to the me- |
thOd of working, and depending upon |
the state Of the gas, whether it re- |
mains constantly saturated, or is SUI
Derheated during a part Of the cycle |
Of working. The temperature of the |
condenser is always determined by |
local conditions. The interior wills |
exceed by degrees to 18 degrees |
the temperature OF the water furnish |
ed the exterior. The temperature |
Of the cooling water varies accord |
ng to the locality from about so de |
grees to 50 degrees in warm elm |
ates. The volitile liquid used in the |
machine ought not at this maximum |
to have a tension above |
that which can be readily managed by !
the apparatus, and if the tension of |
the gas at the minimum temperature |
is too low, it becomes necessary to |
give the compression cylinder large |
The gases or yapors generally a. |
valuable are sulphuric ether, sulphur |
Gus oxide, ammonia, methylic ether, |
and carbonic acid. The machiga in
question uses carbonic acid. The ten |
sion of this gas at q temperature of |
50 degrees is 676.9 lbs per square !
inch and at 80 degrees it is 1908 |
lbs per square inch.
In comparison with the other va
pors named. caTbonic acid requires
a smaller compressor and this fact,
together with its inoffensive charact-
er make it seem to be the ideal ice