Scientific American Supplement, No. 430, March 29, 1884Various
Science
Scientific American Supplement, No. 430, March 29, 1884
Various
Science -- Periodicals
It is easy to make, easy to manage, practically
indestructible, and for commercial purposes has, I think, a general
adaptability which will bring it, in one form or another, into almost
universal use. I may say that when we are in a special fix, this has in
every case landed us out of the difficulty.
For heating large plates of metal equally, for drying paper impressions
for stereotypers, hot pressing hosiery, crumpet baking, working up
plastic masses which can only be worked hot, and work of this class, a
number of separate flames equally diffused under the whole surface of
the plate are necessary to equalize the heat, unless the plate is very
thick, and these are better if produced by a mixture of gas and air; but
in heating wide plates one difficulty must always be remembered, the
burnt gases from the center flames can only escape by passing over the
outer flames, and therefore a space must be left between the top of the
flame and the plate, or the outer flames will be smothered and make a
most offensive smell.
In hosiery presses, printers' arming presses, and many others, the top
plate also requires to be heated. The best way to do this is to use a
number of blowpipe flames directed downward. In many cases the supply
of air under pressure is a practical difficulty and objection. This is
overcome, to a certain extent, by the use of a thick upper plate with a
number of horizontal holes, into which a Bunsen flame is directed. In
every case I have seen, without one single exception, the holes are
either too small, or the burner is placed too close, and the consequence
is that the gas, instead of burning inside the holes, as it should,
passes through partially unburnt, and is consumed at the opposite end,
where it is absolutely useless, the flame not being in contact with or
under the surface to be heated, and therefore doing no work. In hosiery
presses this is a great objection, as the holes are so long that an
equal heat is simply impossible, and the only remedy is to use a
blowpipe flame, which forces sufficient air in with the gas to insure
combustion where the heat is necessary. The same remark applies to crape
and embossing rollers.
For the production of heat in confined spaces and difficult position,
the use of an artificial blast of air is becoming an acknowledged
necessity, and the small Roots blowers now made for such purposes, and
driven by power, are coming rapidly into use.
Public-domain text, read in full here on John Shaqi.
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