IMPROVEMENTS IN THE METHOD AND APPARATUS FOR THE RECOVERY OF LEAD AND OTHER METALLIC SUBSTANCES FROM FURNACE FUMES
Year: 1882

page_text: LETTERS PATENT to Edward Alfred Cowper and Thomas Sopwith both of
No. 6 Great George Street Westminster in the County of Middlesex for an
invention of "IMPROVEMENTS IN THE METHOD AND APPARATUS FOR THE
RECOVERY OF LEAD AND OTHER METALLIC SUBSTANCES FROM FURNACE
FUMES"
PROVISIONAL SPECIFICATION left by the said Edward Alfred Cowper
and Thomas Sopwith at the Office of the Commissioners of Patents on the
4th April 1882.
EDWARD ALFRED COWPER and THOMAS SOPWITH, both of No. 6 Great George
Street Westminster in the County of Middlesex, "IMPROVEMENTS IN THE
METHOD AND APPARATUS FOR THE RECOVERY OF LEAD AND OTHER METALLIC
SUBSTANCES FROM FURNACE FUMES"
Our Invention relates to means of recovering lead and other metallic substances
which are usually carried suspended in the fuines passing away from metallurgical
furnaces, thus involving a considerable loss of valuable material and damage to
adjoining property.
For this purpose we arrange diaphragms of porous woven fabric preferably such
as is of a fibrous character, such as flannel, in a horizontal or inclined position, and.
the fumes being brought under the fabric the gases may pass upwards through it,
and the deposit of solid matter which takes place against the underside of the
fabric, may drop off of its own accord by gravity on to the floor of the flue or
chamber in which the fabric is placed; and we provide such a very large extent
of fabric, and cause the upward current to pass through it at an excessively slow
rate, so that the fabric does not become choked by solid matter, and the natural
draught of the chimney, is sufficient without any mechanical blowing or forcing
of the draught, or other artificial means being employed to increase the
draught.
The said apparatus is preferably placed at some considerable distance from the
furnaces giving off the fumes, so that the temperature of the fumes is considerably
T

page_text: lowered before reaching it but a further reduction of temperature may be effected
by any ordinary means of cooling, or by letting in a portion of cold air to mix
with the fumes.
As it is extremely desirable to avoid frequent stoppage of the works, in order to
clean out the deposit from the apparatus used, it is preferred that there shall be a
considerable depth of chamber or flue below the fabric, so that with lead furnaces
for instance, it is not necessary to clean out the large amount of deposited matter
oftener than twice a year.
If in any case the deposited matter should cling to the fabric at all, we provide
handles and rods connected to the frames from which the fabric hangs, so that the
fabric may be slightly shaken by moving the handles, which are outside the
chambers or flues.
We find it advantageous to combine the sifting or filtering arrangement above
described with arrangements for effecting preliminary deposit of a considerable
portion of the suspended matter such as are described in the Specification to
Letters Patent granted to us on the 8th July 1880 No. 2807. Thus the fumes
after passing through the depositing channels and chambers as described in
the said Specification, if they still retain suspended matter, are caused to pass
through the porous fabric by which they are effectually cleared of the suspended
matter.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Edward Alfred Cowper and Thomas Sopwith in the Great Seal
Patent Office on the 3rd October 1882.
EDWARD ALFRED COWPER and THOMAS SOPWITH both of No. 6 Great George
Street Westminster in the County of Middlesex "IMPROVEMENTS IN THE METHOD
AND APPARATUS FOR THE RECOVERY OF LEAD AND OTHER METALLIC SUBSTANCES
FROM FURNACE FUMES"
Our invention relates to means of recovering lead and other metallic substances
which are usually carried suspended in the fumes passing away from metallurgical
furnaces thus involving a considerable loss of valuable material and damage to
adjoining property.
For this purpose we arrange diaphragms of porous woven fabric preferably
such as is of a fibrous character, such as flannel, in a horizontal or inclined
position, so that the fumes being brought under the fabric, the gases may pass
upwards through it, and the deposit of solid matter which takes place against the
underside of the fabric may drop off of its own accord by gravity on to the floor
of the flue or chamber in which the fabric is placed; and we provide such a very
large extent of fabric, and cause the upward current to pass through it at an
excessively slow rate so that the fabric does not become choked by solid matter,
and the natural draught of the chimney is sufficient without any mechanical
blowing or forcing of the draught, or other artificial means being employed to
increase the draught.
The said apparatus is preferably placed at some considerable distance from the
furnaces giving off the fumes so that the temperature of the fumes is considerably
lowered before reaching it but a further reduction of temperature may be effected
by any ordinary means of cooling or by letting in a portion of cold air to mix with
the fumes.
As it is extremely desirable to avoid frequent stoppage of the works, in order to
clean out the deposit from the apparatus used, it is preferred that there shall be a
considerable depth of chamber or flue below the fabric so that with lead furnaces
for instance, it is not necessary to clean out the large amount of deposited matter
too frequently.
There are two dampers, one on the inlet or branch flue from the main flue to the
apparatus, and one on the outlet or branch flue from the apparatus to the main
flue, and when the apparatus is at work, these are open, and a damper in the
main flue itself is shut; but when it is desired to stop the apparatus for
cleaning out deposit; the damper in the main flue is opened, and the others
are shut.
If in any case the deposited matter should cling to the fabric at all, we provide
handles and rods connected to the frame from which the fabric hangs, so that the
fabric may be slightly shaken by moving the handles which are outside the
chambers or flues.
The forms and arrangements of the apparatus may be varied to suit various
localities or other conditions. As an example of how our invention may be
practically applied we have shewn in the accompanying drawings an arrangement
of chambers and porous fabrics such as in many cases will be found suitable.
Fig. 1 is a sectional plan and Fig. 2 a longitudinal section of a set of chambers,
Figs. 3, 4, 5 and 6 shew parts of these drawn to an enlarged scale, that is to
Bay Fig. 3 is a part longitudinal and Fig. 4 a part transverse section of one of the
chambers, Fig. 5 a section looking towards the end where the fumes enter the

page_text: chamber, and Fig. 6 a section looking towards the end where they leave the chamber.
A is a part of the flue or channel by which the fumes flow from the furnace on
their way to the farther part A'. By shutting the damper B, and by opening the
dampers B1 and B2 the fumes are diverted into a set of chambers C through which
they have to pass, their velocity being very much reduced in consequence of the
large area of passage afforded to them. In these chambers C hang the sheets D
of porous fabric, which in order that they may expose a large surface may be
arranged with double folds as shewn, that is to say, their side edges may be
attached to the side walls of the chambers, their middles attached to bars E
suspended from the crowns of the arches that cover the chambers, and their inter-
'mediate folds weighted down by bars F lying in them. The bars E by which the
middles are suspended are attached to handles G extending outside the chambers
so that they can be pulled up and down to shake the fabric as indicated in Fig. 4
or they may be attached to cranked spindles Has shewn in Fig. 3 so that by
turning these cranks the fabric can be shaken laterally. The fumes enter each
chamber by the lower opening K at the one end and after rising from the lower
part of the chamber through the pores of the fabric to the upper part of the
chamber pass away by the upper openings L at the other end of the chamber,
as indicated by the arrows. The solid matters suspended in the fumes are mostly
arrested by the fabric and fall or are shaken from it to the floor of the chamber
whence they are from time to time removed, doors M being provided to give access
for this purpose.
. Instead of thus dealing direct with fumes taken direct from the furnace, it is
advantageous to clear them in the first place of a portion of their suspended
matters by causing them to pass through depositing chambers arranged as described
in our Patent dated 1st February 1881, so that before the fumes reach the fabric,
where the separation takes place, they shall have become sufficiently cooled and
also have parted with the denser and bulkier particles carried by them.
Having thus described the nature of our invention and in what manner the same
is to be performed, We claim:
First. The herein described method of recovering lead and other metallic
substances from furnace fumes by causing the fumes to pass slowly in an upward
direction through porous fabric, so that the solid particles arrested by the fabric
fall to the floor of a chamber where they are collected for removal.
..
Second. The arrangement, of chambers with porous fabrics suspended therein
substantially as described with reference to the accompanying drawings
In Witness whereof we the said Edward Alfred Cowper and Thomas
Sopwith have hereunto set our hands and seals this twenty eighth day
of September in the year of Our Lord One thousand eight hundred and
eighty two.
E A COWPER (L.S.)
T. SOPWITH
(L.S.)