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

REFRIGERATOR CARS 445
those in the top layer were over 2° higher. Car B, on the contrary,
brought in the load from 6 to 14° lower than car A. These two cars
were loaded with 600 cases of eggs and, so long as the atmospheric
temperatures were above 80° F., refrigeration was of doubtful efifi-
ciency. The third and fourth days of the trip were unseasonably
cool and also rainy, which compensated for the lack of <strong>insulation</strong> in
the roof and permitted the load in the car B to drop below 55° F.
before the end of the fourth day.
The performance of a poorly built car, said to contain an inch
and a half of <strong>insulation</strong> throughout, as compared with a well built
car known to have one and a half inches of <strong>insulation</strong>, is well illus-
trated in Charts X and XI, where cantaloupes were hauled for
eleven days across a hot territory. The top layer in car A, loaded
six wide and four high at the bunkers, was in such bad condition on
arrival that claims were filed for damage in transit. Car B, on the
other hand, was in good condition, although the load was seven cases
wide and four cases high. In car A the combination of a lack of
cold air circulation and of <strong>insulation</strong> proved disastrous, even though
the load was light and open in character, and much easier to refrig-
erate than a load of eggs. In fact, we know that eggs can not be
safely loaded more than three layers high in summer weather in
cars having one inch of <strong>insulation</strong>. Cars having one and one-half
inches of <strong>insulation</strong>, if provided with a basket bunker and a floor
rack, can carry four layers. To load five high, we must have three
inches in the roof and two inches in the walls, ends and floors, and
good air circulation. Beyond five layers of egg cases we have not
succeeded in getting good refrigeration.
This is <strong>illustrated</strong> in Chart XII, showing top and bottom layer
temperatures in two cars stowed six layers high, making 700 cases
to the load. Car A is of the same type as was used in Chart VII, where
with 600 cases it did good work. With 700 cases there was practically
no refrigeration except in the bottom layer. The companion
car, B, with the same <strong>insulation</strong> but having a box bunker, did not
even refrigerate the lower layers. The packages on the floor, middle
of the car, were often warmer than the top of the load, which was
only 12 inches from the ceiling. It varied more than 5° with the
daily rise and fall of the atmosphere and arrived at destination
showing an increase of 7.5°.
Encouragingly good results have been obtained in refrigerating
heavy loads of fruit in the basket bunker cars by adding salt to the
ice in the bunkers. On a long haul across a hot territory salt has
been added to the ice at the first three icing stations. By that time
(the third day) the load was cooled and very frequently no more ice
was needed, even though the haul continued for five to eight days.
The air issuing from the bunkers is far below 32° F., but the circula-
tion is so rapid that there is no pocketing at the bulkhead. The in-
sulated bulkhead also protects the load so that frosting does not