There is, in addition, a hot and cold water test for bottles
which are specially processed, such as bottles for beers,
beverages, and catsups. This test is applied until the bottle
is broken, which usually takes place at seventy to ninety
degrees Fahrenheit. There are few commercial bottles which
can stand more than ninety degrees shock.
There is also a pressure test for all bottles, the pressure being
applied until the bottle breaks. This usually occurs at seven
hundred and fifty pounds per square inch, the normal pressure
being from three hundred fifty to four hundred pounds. Ring
sections of the bottles are cut and examined under a microscope
for strain and cord (hot and cold streaks in the glass), which
can be seen in this way alone. The bottles are then graded for
these defects, those falling under the classes A, B, and C being
salable, while those with a D rating are unfit for use.
After the bottles have come from the lehr and have been sorted
and tested, they are placed in four different types of packages.
A few bottles are still packed in wooden crates, but most of the
ware is shipped in some kind of carton. There are testboard
corrugated cartons, fibre board cartons which are also testboard,
and city delivery package which is the same type as the testboard
material except that it is non-test. There is another type known
as the crate substitute in which the bottles are placed with
little or no packing, the principle being the same as the old
wooden crates.
Once the bottles are placed in the cartons, they are run through
a machine which seals them at either or both ends as the customer
may specify. They are then taken to the warehouse and either
shipped at once or stored. All ware at Whitall Tatum factories is
stored in modern warehouses covering several acres, which protect
the packages from the weather.
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This is an automatic bottle machine, without the
elaborate compressed air connections or the traveling
belt which takes completed bottles to the lehr.
So many things can happen to a bottle in the process
of manufacture that constant inspection is the only safeguard.
This inspection is for strains and stresses which weaken the
glass.
Bottles are first produced in wood. These models not
only foretell how the glass bottle will look, but guarantee
the exact content of the finished product. |
