REGENERATIVE HOT BLAST STOVES
Year: 1882

page_text: LETTERS PATENT to Edward Alfred Cowper and Charles Edward Cowper'
both of No. 6 Great George Street Westminster in the county of Middlesex
PROVISIONAL SPECIFICATION left by the said Edward Alfred Cowper
& Charles Edward Cowper at the Office of the Commissioners of Patents
on the 19th December 1882.
EDWARD ALFRED COWPER and CHARLES EDWARD COWPER both of N° 6 Great
IMPROVEMENTS IN
George Street Westminster in the County of Middlesex
REGENERATIVE HOT BLAST STOVES
"
"
Our Invention relates to improvements in regenerative hot blast stoves of
the kind usually known as "Cowper's Stoves" which are employed for re-
ceiving heat from the combustion of the waste gases of blast furnaces and for
imparting heat to the air blast, as described in the Specification N° 34 of 1870.
The flues or passages in these stoves have been made of brickwork in various
forms as described in the said Specification N° 34 of 1870 and also in other
Specifications, as in N° 887 of 1872 and N° 1623 of 1874. Our present invention
consists in so shaping the bricks used for forming these flues or passages that,
whilst they are sufficiently strong for transport and handling, when placed together
within the stove they divide the space into a great number of equal and sym-
metrical passages separated from each other by a single moderate thickness of
brick, thus operating more efficiently and uniformly than when double thicknesses
occur both in taking up heat from the burning gases and also in giving out heat
to the air blast. For this purpose we make the bricks as geometrical figures or
segments thereof so selected that they fit to each other and form passages com-
pletely occupying the space of the stove somewhat like the cells of honey combs.
The figures which fulfil these conditions are triangular, square or hexagonal or
approximately of these shapes, preferably having the internal angles of the passages
rounded so as to give less hold for dust in the corners. When triangular bricks
are employed, that is to say bricks having through them triangular holes, every
three of these when placed together enclose also a similar triangular space in the
middle. When hollow square bricks are employed, every four of these enclose a

page_text: square space in the middle. A star shaped brick having a central round hole and
six projecting rays with hollows between them of circular form is a convenient
shape as a number of these when laid together with the rays of the one meeting
the rays of the other form a series of circular flues with only single thicknesses of
brick separating them. Instead, however, of employing the. whole star it is in
many cases preferable to divide it into three segments each of which is symmetrical
in itself, as these can be laid so as to form circular flues, the bricks of the one layer
breaking joint with those of the next. In like manner to form square flues with
rounded corners, the bricks may be made solid in the shape of long rectangles with
parts projecting at each side, the shoulders of the projections being rounded to form
the rounding of the angles of the flues; or these shoulders being made with a slope
of 45°, the bricks when laid together form a series of octagonal flues. In stoves
where the flame and heated gases descend the passages, we make the upper mouths
of the passages larger than the parts below so that there may be ample room for
deposit where the flame and hot gases first enter. For this purpose some of the
bricks or segments are omitted in the upper layers. In order better to distribute
the current throughout all the passages of the stove we provide at the cool inlet
and outlet a crescent shaped baffle plate which prevents the current from setting
directly out of or into the pipe and divides it over the area of the stove so that it
flows equably throughout all the passages.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Edward Alfred Cowper & Charles Edward Cowper in the Great
Seal Patent Office on the 18th June 1883.
EDWARD ALFRED COWPER and CHARLES EDWARD COWPER both of N° 6 Great
George Street Westminster in the County of Middlesex. "IMPROVEMENTS IN
REGENERATIVE HOT BLAST STOVES"
Our invention relates to improvements in regenerative hot blast stoves of the
kind usually known as "Cowper's Stoves" which are employed for receiving heat
from the combustion of the waste gases of blast furnaces and for imparting heat to
the air blast, as described in the Specification N° 34 of 1870. The flues, or passages
in these stoves have been made of brickwork in various forms as described in the
said Specification No 34 of 1870 and also in other Specifications, as in N° 887 of
1872 and N° 1623 of 1874. Our present invention consists in so shaping the bricks
used for forming these flues or passages that, while they are sufficiently strong for
transport and handling, when placed together within the stove they divide the
space into a great number of equal and symmetrical passages separated from each
other by a single moderate thickness of brick, thus operating more efficiently and
uniformly than when double thicknesses occur both in taking up heat from the
burning gases and also in giving out heat to the air blast. For this purpose, we
make the bricks as geometrical figures or segments thereof so selected that they fit
to each other and form passages completely occupying the space of the stove, some-
what like the cells of honey combs. The figures which fulfil these conditions are
triangular, square or hexagonal, or approximately of these shapes, preferably having
the internal angles of the passages rounded so as to give less hold for dust in the
corners. When triangular bricks are employed, that is to say, bricks having
through them triangular holes, every three of these, when placed together, enclose
also a similar triangular space in the middle. When hollow square bricks are
employed, every form of these enclose a square space in the middle. A star shaped
brick having a central round hole and six projecting rays with hollows between
them of circular form is a convenient shape, as a number of these when laid together
with the rays of the one meeting the rays of the other form a series of circular flues
with only single thickness of brick separating them. Instead, however, of employing
the whole star it is in many cases preferable to divide it into three segments, each
of which is symmetrical in itself, as these can be laid so as to form circular flues,
the bricks of the one layer breaking joint with those of the next. In like manner,
to form square flues with rounded corners, the bricks may be made solid in the
shape of long rectangles with parts projecting at each side, the shoulders of the
projections being rounded to form the rounding of the angles of the flues; or these
shoulders being made with a slope of 45°, the bricks, when laid together, form a
series of octagonal flues. In stoves where the flame and heated gases descend the
passages, we make the upper mouths of the passages larger than the parts below,
so that there may be ample room for deposit where the flame and hot gases first
enter. For this purpose, some of the bricks or segments are omitted in the upper
layers. In order better to distribute the current throughout all the passages of the
stove, we provide at the cool inlet and outlet a crescent shaped baffle plate which
prevents the current from setting directly out of or into the pipe and divides it
over the area of the stove so that it flows equably throughout all the passages..

page_text: .
the shape of each passage is hexagonal with rounded corners. The passages are
separated from each other by a single moderate thickness of brick; and each brick
besides itself containing a passage, forms portions of 6 similar passages, so that on
the whole there is a proportion of 3 passages to each brick.
The bricks forming passages of this kind may be divided into segments in various
ways as shewn in Fig. 2. Thus a is one of the bricks made in half; b is one third,
c is one sixth. The star bricks of the kind shewn in Fig. 1 may have passages of
circular form as shewn in Fig 3, and these may be made in segments as shewn in
Fig. 2. Fig. 4 is a sectional elevation on the line x x of Fig. 1, shewing the
arrangement of bond which we prefer to adopt for the purpose of keeping the
passages truly vertical or in line with each other. A certain proportion of the
bricks in the first course are made of a less thickness than the others. After the
first course, bricks of equal thickness are used throughout, except for one course at
or near the top, where a single course similar to the first is used, in order to finish
with a flat or level surface..
d, d, d, d, are bricks of the normal thickness. ee are the thinner bricks. ffare
bricks of the same shape in plan, but having sharp edges on their upper faces so
that at the top of the regenerator there are no horizontal surfaces upon which dust
may lodge.
When other forms of bricks are used, it is of advantage to make those
which constitute the top course sharp edged for the purpose of preventing lodgement
of dust.
Fig. 5 is a sectional elevation shewing bricks such as are shewn at Fig. 1 bonded
together by "breaking joint" in a manner similar to that usually employed in
ordinary brickwork. Fig. 6 shews an arrangement of bricks giving triangular
passages, and fig. 7 an arrangement of bricks giving square passages. Fig. 8 shews
triangular passages formed by star bricks; and Fig. 9 shews square passages
formed by star bricks.
Fig. 10 shews another arrangement of bricks forming square passages with
rounded corners. 'Each brick g has in this case at each side a projecting part h,
the shoulder of which gives the rounding of a corner: The shoulder of the projecting
parts h instead of being rounded may be made plane at an angle of 45° this giving
octagonal passages.
jjare long bricks which may be used for one or more courses at the top of the
regenerator, giving larger passages for flame and heated gases to enter for some
distance. Similar bricks may be used for the upper courses to those shewn in Figs. 7
and 9; and the upper faces of those used for the top course be bevelled off to form
edges.
Fig. 11 is a plan and Fig 12 a sectional elevation on the line Y Y shewing top
course bricks formed to suit the hexagonal passages of Fig. 1, or the circular
passages of Fig. 3. Figs. 13 and 14 are sectional plans shewing arrangements
according to our invention for better distribution of the current throughout all the
passages of the regenerator. In Fig. 13 is the chimney valve and o the cold
blast, and m is a curved baffle-plate or set of plates which divide the passage so as
to cause the chimney to draw at once from several points on the side opposite the
flame flue, when the stove is being heated by the gas flame, and similarly to cause
a distribution of the incoming air when the stove is heating the blast. This baffle
may be continued a greater or less distance round the stove, and have any desired
number of openings in it. It may be of metal or brick or ceramic material, and it
may form part of the structure of the stove or it may be placed in the stove
independent of the structure.
Instead of placing or forming the baffle within the stove as shewn in Fig. 13 a
distributing passage may be arranged outside as shewn in Fig. 14 where n is a
casing which may be of iron plate, connecting the chimney valve 1. to several
passages opening into the stove.
Having thus described the nature of our invention and in what manner the same
is to be performed, we claim in respect of regenerative hot blast stoves:-
First. The use of bricks of forms, other than the usual rectangular form and so
-

page_text: shaped that when placed together they form a number of equal and symmetrical
passages each separated from the next by a single moderate thickness, substantially
as and for the purposes herein set forth.
Second. In combination with the cool inlet and outlet the use of a crescent
shaped baffle for distribution of the currents, substantially as herein described.
In Witness whereof We the said Edward Alfred Cowper and Charles Edward
Cowper have hereunto set our hands and seals this eighteenth day of
June in the year of Our Lord one thousand eight hundred and eighty-three.