IMPROVEMENTS IN APPARATUS FOR SEPARATING DUST FROM THE GASES EVOLVED FROM BLAST FURNACES FOR SMELTING IRON
Year: 1865

page_text: PROVISIONAL SPECIFICATION left by Edward Alfred Cowper and
Charles William Siemens at the Office of the Commissioners of Patents,
with their Petition, on the 19th September 1865..
We, EDWARD ALFRED COWPER, of No. 354, Great George Street, West*
minster, in the County of Middlesex, and CHARLES WILLIAM SIEMENS, of
No. 3, Great George Street, aforesaid, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN APPARATUS FOR SEPARATING DUST FROM
THE GASES EVOLVED FROM BLAST FURNACES FOR SMELTING IRON," to be as
follows:-
We are aware that in numerous cases water and other liquids containing
dirt or minute particles of various substances have been run into reservoirs or
vessels to allow such substances to sink to the bottom or become deposited,
and in some cases the liquid has been left entirely stationary for a length of
time, whilst in other cases it has been slowly fed in and as slowly withdrawn.
We are also aware that aeriform fluids such as atmospheric air charged with
dust or "stive" from a flour mill have been caused to traverse a series of
shallow passages in order that the foreign substances might become deposited;
and in certain iron works in France the gases from the top of a blast furnace
have been caused to traverse a long pipe having some water in the bottom of
it with the view of causing the dust to be deposited.
Now, we have found, from numerous experiments with apparatus con-
structed according to our Invention, that in order fully to deposit the dust
from the gases from a blast furnace for smelting iron, it is necessary that the

page_text: gases should travel very slowly indeed, a good velocity for the purpose being
about one foot per second or a little slower; the dust will then gradually
drop out of the stream of gas, but if the gas is all contained in one large
tube, a very considerable and inconvenient length of tube will be required;
we therefore form a very large tube or box having a large number of horizontal
or inclined shelves or trays in it placed very close together, one above the
other, so that as the gases pass very slowly between the shelves in thin or
shallow streams, the dust has but a very small height to fall before it reaches
a shelf, and is thus deposited; and we find that a convenient distance between
the shelves is from about one inch to four inches, according to the foulness of
the gases and the size of apparatus used, but the shelves may be placed a
little nearer or further apart if desired.
The apparatus may be conveniently formed of a large vertical wrought-iron
box reaching from the top of the blast furnace down to the ground, and this
may be divided into a number of chambers, and the gases are distributed
amongst these chambers from a vertical pipe down one side of the apparatus,
whilst another vertical pipe takes away the gases after they have passed
through the chambers, the chambers themselves being provided with a number
of shelves fixed alternately at opposite sides, so that the gases may traverse
them in succession, one after the other, and deposit the dust thereon. In
this apparatus the shelves may be horizontal or inclined. The shelves may
be either flat or of corrugated sheet iron or cast iron, or they may be made flat
with angle iron, T-iron, or other iron fixed on them.
Our apparatus for separating dust from the gases is so arranged as to be
easily cleared of dust by scrapers, or by water from a jet and hose, or by
steam, gases, or air blown in with force; but we prefer the use of water under
pressure supplied through a hose, and directed by means of a jet on to each
part of each shelf in succession, so as thoroughly to wash or "flush" out all
the dust at such times as convenient. We also construct apparatus with a
box containing shelves parallel to the sides of such box, and place the whole
at an inclination so that the gases may either pass direct through or may
traverse the length of the box several times, and deposit the dust contained in
them, and we wash out the dust from such shelves by water under pressure
supplied through a hose and jet pipe, or by a powerful' jet of steam, air, or
gas. There are provided openings with doors for the introduction of the jet
or jets, and for the dust to be driven out at, as well as a box or compartment
at the bottom of the apparatus to receive the dust.
The gases from a blast furnace, after having thus had the dust separated
from them, are admirably adapted for producing heat by combustion in such

page_text: hot blast stoves as described in the Specification of a Patent granted to
Edward Alfred Cowper, and dated 19th May 1857 (No. 1404), and such
gases may also be used with great advantage for heating the common
description of hot blast stoves having iron pipes, as well as for heating boilers,
and other purposes.