The Mellette County pioneer. [volume] (Wood, Mellette County, S.D.) 19??-1971, 1920-04-30

Il furnace which gives q tenn N&ME
perature of $500 C-enough to $500
~volatilize diamonds. A compari- NM#NM
son of these temperatures with ME&8A
that Of the sun, which is esti- nsynm,
mated at 5000 c., gives a strik- @@s# -
ing idea of what can be accom- va M
plished in handling refractory M~
substances with electric heat. \MItms%w%
There are other types of cleo N~~s
trio furnaces, which, although &xMs
simple in construction, are capa-
bic of doing in one operation S
things which formerly took sew
eral heatings. In making shells, r g
for example, for large caliber
guns. it is necessary to expose
different sections of the same shell to different
degrees of heat. With an electric furnace this is
done by simply combining heat units of varying
resistance, according to the degree Of heat de-
sired, in the same furnace.
The war was responsible for many new devices
designed with a view to increasing production
quickly. One Of the things the government need
ed most was ships-lots Of them, and in building
ships an enormous amount of rivets have to be
heated. and that quickly. The usual method or
heating these rivets was in a forge, usually burn
ing coke or oil as fuel, which was after a care
full survey, found to be woefully inefficient. The
attendance was large, requiring q blower man as
we'll as a passer; large quantities of rivets were
burned. welded tOgetneT, OF lDSuIHClently uedteu
in the forge, and when 1t had to be taken into the
hold Of the ship for use, the difficulties Of Oper-
alton were only exceeded by the vileness of the
atmosphere resulting from the fumes Of the forge.
The result was the electric rivet heater. Rivets
are now heated by inserting them between two
copper bars carrying a heavy current, supplied
by a transformer. Since the iron of the rivets
themselves is q material Of high resistance, they
are heated thoroughly and quickly. The bars are
operated by a foot pedal, so that when the rivets
are removed, or are being placed in position to
be heated, the current ceases to flow. The whole
apparatus is easily portable.
II was found that this simple machine heated
the rivets throughout that, inasmuch as the en-
ergy was used only when the rivets were actually
being heated, there was no waste Of heat that
there were no noxious fumes or spoiled and vast
ed rivets, and that the machine was nearly fool
proof. The attendance was reduced TO q mini
mum, and there was no necessity of supplying
fuel, with the consequent trouble in disposing Of
the ashes when it was being operated in more
or less inaccessible parts of a ship. 1t has q ca
pacity of 500 A-inch rivets, / inch long per
hour, which is enough under ordinary conditions
for a gang of gun riveters.
The place where electric heat has found its
greatest application, from the standpoint of num-
Der of installations at least, is in the electrically
heated oven, or air-drying and baking apparatus,
as one prefers. 1t is surprising how many prod
ucts that are necessities of our everyday life re-
quire an oven treatment somewhere in the course
of their manufacture.
Electric ovens are used more in the automobile
industry than in any other field. Here 100, 600
XIV are used in baking the japan on 5000 auto
mobile bodies every day. In a few years the au-
tomobile whose japanned parts are not baked in
an electric oven will be q rarity. Other large
users of electric ovens are foundries, for baking
cores; telephone and typewriter manufacturers
manufacturers of iron and bed frames, and chem
ical manufacturers Of various sorts.
Oven processes include baking, air tempering,
drying and sherardizing. OF these four the first
is the most used, the other two are quite COM
mon, and the last is a process for protecting ex-
posed iron parts from corrOsion.
In many Of these processes, accurate regulation
of heat, and automatic control are absolutely nee
essary, because many materials are irrevocably
ruined by a slight change in the temperature Of
the oven. And here again manufacturers have
found that the saving In material which was
spoiled by the vagaries of the fuel-heated furnace
has more than paid for the increased expense of
installing and operating a bank of electric ovens.
OF these three classes Of ovens, those installed
for baking are the most numerous. The work
they do varies: baking japan on various articles,