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

402 CORK INSULATION
(b) Control of the humidity of the constant temperature room should
be effected by suitable means, tests having demonstrated that a consider-
able increase in the percentage of ice melting is effected by increasing the
percentage of relative humidity in a constant temperature room from a
low to a high point.
(c) The mixture of ice and salt should be carefully regulated on the
basis of weight.
(d) The salt should be of standard specifications.
(e) The ice used should be only hard, "black" ice, and should be
crushed to uniform size. The finer the ice is crushed and the more salt
used, the lower, within limits, will be the resultant temperature.
(f) Ice and salt should be mixed thoroughly in suitable mixing box
located outside the test room, and packed in the ice cream cabinet during a
fixed period, at the same hour, every other day (48-hour icing), no ice
and salt to be put on top of cans and brine to be drained off cabinet before
each re-icing.
(g) The ice cream to be used for test purposes should be a product of
rigid specifications, because different mixtures and flavors require different
temperatures to keep them in satisfactory condition, and the volume
of ice cream in the cabinet should be a fixed quantity.
(h) Special long-bulb thermometers should be used in ice cream cabi-
nets, of such length as to obtain average temperature readings for the
total depth of the ice cream and for the empty can of each cabinet.
(i) Four days preliminary operation should be allowed to establish
a temperature equilibrium in the walls of the cabinet before the test proper
should be started, and the test should then continue for 30 more days.
Tests performed under standardized conditions thus sug-
gested, values for such standards to be fixed upon a practical
basis for test purposes and a basis most nearly conforming to
the practices of the ice cream industry, should be comparable,
as to ice consumption, cabinet air temperature, ice cream tem-
perature, and condition of the ice cream throughout the test.
An electric ice cream cabinet may be tested in much the
same fashion, the electric power consumption by the cabinet
machine, instead of the ice consumption, being comparable
with results of other electric cabinet tests.