Cork insulation; a complete illustrated textbook on cork insulation ...

400 CORK INSULATION
loss of efficiency in operation. Such spaces that cannot be effectively
sealed with corkboard sheets, are packed tight with a special waterproof
sealing material combined with a suitable proportion of prepared
cork particles.
Maintenance Cost.—It is believed that the construction of this
cabinet is an effective guarantee of lowest power and maintenance
costs, when operated in conjunction with the Absopure refrigerating
unit.
Manufactured by the General Necessities Corporation, Detroit,
Michigan.
162.—Notes on How to Test Ice Cream Cabinets.—There
are no generally accepted and approved methods for the testing
of either ice and salt cabinets or mechanical ice cream
cabinets, and most all tests made thus far are subject to more
or less inaccuracies and interpretation as to the meanings of
the results obtained. For instance, as mentioned for house-
hold refrigerators, it has been for years a well-understood
fact in the cold storage industry that the efficiency of a new
cold storage room is in itself of ver}' minor importance, if of
any real importance at all. What is important to the owners i
and operators of large cold storage plants, is what the effi- j
ciency of that room will be one year or ten years after it has
been in operation ; for it is possible to construct hollow walls
of wood, fill the space with chimney soot and show under
accurate test an initial cold room insulating efficiency far
greater than could probably be shown with any commercial
insulating material procurable, }et the soot would retain its
remarkable efficiency for a very short time only. Glass wool,
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fluxed limestone, wood flour, medicinal cotton, nail polish, and
many other materials* in common use, are very efficient thermal
insulators, but quickly lose their heat retarding properties
by settling and packing down and by saturation with condensed
water vapor, if used in connection with cold tempera-
tures.
The first point to cover in planning for tests of any ice ;
*In a number of the "Berichte" (1899), Prof. Hempel describes a series of experiments
undertaken by him, in order to determine which substance was best suited
for isolating freezing mixtures in experimental wcirk in the laboratory. Starting
with a temperature of about -75° to -80° C. (-103° to -112° F.) produced by solid
carbon dioxide and ether, the rate of rise of temperature with time was measured,
and, as a result, eiderdown was found to be the lust irsiilator. woo', carefully dried
at 100° C. (212° F.) being nearly as good, and having the advantage of cheapness.
Thus wi"tfi eiderdown a rise of 12° C. occurred in eighty-eight minutes, with dry wool
a rise of 20° to 24° C. in the same time.