IMPROVEMENTS IN REGENERATIVE HOT BIOM STOVES FOR HEATING AIR. STEAM. AND OTHER GASES
Year: 1870

page_text: LETTERS PATENT to Charles William Siemens, of No. 3, Great George
Street, Westminster, in the County of Middlesex, and Edward
Alfred Cowper, of No. 6, Great George Street aforesaid, and¨
Charles Cochrane, of the Ellowes, Upper Gornal, in the County of
• Stafford, for the Invention of "IMPROVEMENTS IN REGENERATIVE HOT
BIOM STOVES FOR HEATING AIR. STEAM. AND OTHER GASES."
-
PROVISIONAL SPECIFICATION left by the said Charles William
Siemens, Edward Alfred Cowper, and Charles Cochrane at the
Office of the Commissioners of Patents, with their Petition, on the
5th January 1870.
.
We, CHARLES WILLIAM SIEMENS, of No. 3, Great George Street,:
Westminster, in the County of Middlesex, and EDWARD ALFRED
COWPER, of No. 6, Great George Street aforesaid, and CHARLES
COCHRANE, of the Ellowes, Upper Gornal, in the County of Stafford,
do hereby declare the nature of the said Invention for "IMPROVEMENTS
'

page_text: IN REGENERATIVE HOT BLAST STOVES FOR HEATING AIR, STEAM, AND OTHER
GASES," to be as follows:---
It has hitherto been found in employing regenerative hot blast stoves
as constructed according to E. A. Cowper's Patent No. 1404, of 1857,
that when waste gases from blast furnaces are used therewith without
previous purification, the dust passing into the stoves with such gases is
deposited in the "chequered work" inside the regenerators, and thus
becomes very detrimental to the perfect action of the stoves, and we
have found that the arrangements of "fire-bricks" and "perforated tiles
or blocks" forming the "chequered work" as shown and described in
the above-named Specification and hitherto employed in the said hot
blast stoves do not admit of being effectually cleaned out by a brush or
cleaning instrument as there is not sufficient room to pass a brush or
cleaning instrument through the perforations in the "perforated tiles or
blocks," even without taking into account the slight irregularities that
always occur in brickwork or the fact of the tiles or blocks moving
somewhat relatively to each other from expansion and contraction by
heat, but even had it been possible to do so the extreme amount of
labour caused by separately manipulating twenty-one to forty-eight
holes in every "perforated tile or block" filling the large regenerators
required for hot blast stoves, would have rendered any such mode of
cleaning entirely. abortive and uneconomical, and it has therefore been
found in practice absolutely necessary, in cleaning out a stove, to take out
the whole of the "fire-bricks or perforated tiles or blocks" forming the
"chequered work," thereby entailing very considerable expense and great
delay.
Now our Invention has for its object so to construct the " chequered
work
"
or filling in" of the stoves that while the current of air or gas
passing through the same is effectually broken up or disturbed and
brought into contact with extended- heated or heat absorbing surfaces,
yet the passages of the "filling in" are so formed that a brush or cleaning
instrument can readily be passed down the same for effectually cleaning
them from the deposit. Such "filling in" can be constructed in a
great variety of ways, for the, purposes of, this Invention; thus in one
arrangement it consists of vertical continuous passages; or flues of a
circular, square, or polygonal transverse section, on the side surfaces of
which are formed, either helical, inclined, vertical, or horizontal pro-
jecting ribs or fillets, against, which the current of air or gas in passing.

page_text: up or down is caused to impinge, whereby it is disturbed or turned over
so as to bring the central portion of the current to the outside, such
projections still leaving ample room to pass the rod of the brush or
cleaning instrument through. When horizontal or somewhat inclined
projections are used, these may be arranged either alternately on opposite.
sides, so as to form more or less a zig-zag passage or they may be made
opposite each other, so as to produce alternate enlargements and con-
tractions of the passages. When helical projections are used these may
be in lengths turning alternately right handed and left handed, or in
place of such helical and other projections the entire passage may be
made of a helical or twisted or zig-zag form or with alternate enlarge-
ments and contractions always so arranged, however, that a central
straight passage shall be left for the rod or suspending cord of the
cleaning brush or instrument. Again the filling in may be built up
of superposed layers of bars or slabs arranged to cross cach other at
right angles or at any other angle, but so that the bars or slabs of the
several layers lying in the same direction are not "placed over the spaces
between" them or made to break joint as heretofore and as described in
the before mentioned Specification, but are arranged vertically one above
the other, so as to leave vertical spaces passing right through all the
layers through which the brush or cleaning instrument may be passed.
Or the bars or slabs may be so arranged as to leave slanting or inclined
passages in place of vertical ones for passing the brush or cleaning
instrument down.
In some cases when it is wished to reduce the friction of the air
through the stoves to a. minimum, and it is therefore not considered
desirable to obstruct the air very much by the introduction of con-
siderable projections into straight passages, we purposely build the filling
in or brickwork so as to produce rough surfaces sufficient to cause the
requisite disturbance in the air, but in such cases we provide: ample
room in the passages for large and efficient brushes or cleaning,
instruments; being used so that the surfaces. may be kept particularly
clean in order to cause the communication of the heat to take place with
sufficient rapidity.
Or we construct one deep and narrow spiral passage (or it may be
portions of concentric circles leading into each other), commencing at
the central shaft and winding round and round to the outer circumference

page_text: of the. stove, which passage may be cleared out through apertures in the
top and bottom.
Or we construct a number of helical or screw-like passages going
round and round the central shaft of the stove, similar to spiral staircases
and of a sufficient size to allow of a boy or man passing through them
for cleaning them out, while loose bricks or slabs of fire-brick may be
placed at intervals in the passage by the boy or man in order to break
up the current of air or gas, or the passages in place of being spiral
may be horizontal and circular or segmental on plan with steps or drops
from one layer to the next, and at such steps or drops we sometimes
form large manholes or pits the better to enable a man to clean out
the passages with a brush or other cleaning instrument, in which cases
the passages need not be made large enough to admit a man, but must
be amply large enough to admit a good strong brush or other cleaning
instrument, and also allow room for a considerable deposit of dust; or
similar passages in place of passing round and round the central shaft
may pass backwards and forwards in the stove dropping at each end
one step to the next layer of passages, which passages can be con-
veniently closed at one end by loose bricks put into their places by a
man in the vertical flue up which the inflamed gas usually passes.
One plan for dislodging dust from the stove and a very efficient one
which we sometimes employ, consists in exploding a small quantity of
gunpowder or other explosive compound in the lower or upper portion
of the stove, but by preference in the lower portion. The powder should
be confined in a stout cartridge or maroon so as to explode with some
violence, thereby creating such a concussion in the air as to throw off
a large quantity of the dust that adheres to the side surfaces and from
any of the flat surfaces.
Another part of our Invention consists in employing in place of or
in conjunction with a brush or other cleansing instrument for cleaning
out the air passages through the "filling in" a blast pipe or pipes for
air or steam or both, so arranged as to be applicable for blowing through
the several passages one after the other, or through several at once, so
that the energy of the blast may not be lost over the whole area of the
'filling in," but may be concentrated as much as is necessary to
remove dust or deposit. One pipe arrangement suitable for the purpose
consists in a vertical pipe and stuffing box at the top of the stove, and
€6

page_text: having an arm or arms attached to its lower end carrying blast jets.or
nozzles to blow down the passages, the whole being rotated from the
top, after its introduction into the top part of the stove through the
manhole. In order to vary the radius at which the jets act the arms
are provided with elbow pipes that can open or close so as to increase
or diminish the distance from the centre, or the arm or arms are caused
to slide with telescope joints in or out. The apparatus may be put
together by introducing the arm or arms at a small door at the side of
the stove, and screwing them into the vertical pipe or it into them..
Also flexible pipes or pipes with joints in them are to be used in the
bottom part of the stove for cleaning, and the steam or air valve may
be arranged to be opened very suddenly so as to give sudden puffs of air
or steam. In place of or in addition to the above named pipes for
blowing out dust, other pipes are introduced when necessary through
holes in the top of the stove, and are thrust down as far as may be
necessary in order to remove dust, there being provided openings or jets
in the sides of such pipes, so that on a blast of air or steam, or both
being applied through the pipe it may take effect at the level at which
the jet or jets happen to be, the pipe being raised and lowered and
turned round as necessary, or it may be thrust down each passage
separately to blow the dust out, in which case it can best be manipulated*
by a man in the stove, the air or steam being supplied through a
flexible pipe.
5
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Charles William Siemens, Edward Alfred Cowper,...
and Charles Cochrane in the Great Seal Patent Office on the 4th.
July 1870.
TO ALL TO WHOM THESE PRESENTS SHALL COME, wc, CHARLES,
WILLIAM SIEMENS, of No. 3, Great George Street, Westminster, in the
0 County of Middlesex, and EDWARD ALFRED COWPER, of No. 6, Great
George Street, aforesaid,. and CHARLES COCHRANE, of the Ellowes,:
Upper Gornal, in the County of Stafford, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by IIer-
Letters Patent, bearing date the Fifth day of January, in the year
5 of our Lord One thousand cight hundred and seventy, in the thirty-third

page_text: year of Her reign did, for Herself, Her heirs and successors, give and
grant unto
us, the said Charles William Siemens, Edward Alfred
Cowper, and Charles Cochrane, Her special licence that we, the said
Charles William Siemens, Edward Alfred Cowper, and Charles Coch-
rane, our executors, administrators, and assigns, or such others as we,
the said Charles William Siemens, Edward Alfred Cowper, and Charles
Cochrane, our executors, administrators, and assigns, should at any time
agree with, and no others, from time to time and at all times thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
IMPROVEMENTS IN REGENERATIVE HOT BLAST STOVES FOR HEATING AIR, STEAM,
AND OTHER GASES," upon the condition (amongst others) that we, the said
Charles William Siemens, Edward Alfred Cowper, and Charles Cochrane,
our executors or administrators, by an instrument in writing under our
or their hands and scals, or under the hands and seal of one of us or
them, should particularly describe and ascertain the nature of the said
Invention, and in what manner the same was to be performed, and
cause the same to be filed in the Great Seal Patent Office within six
calendar months next and immediately after the date of the said Letters:
< C
Patent.
NOW KNOW YE, that I, the said Edward Alfred Cowper, on behalf
of myself and the said Charles William Siemens and Charles Cochrane,
do hereby declare the nature of the said Invention, and in what
manner the same is to be performed, to be particularly described and
ascertained in and by the following statement thereof, reference being
had to the accompanying Drawings and to the figures and letters marked
thereon, that is to say :-
It has hitherto been found in employing regenerative hot blast stoves,
as constructed according to E. A. Cowper's Patent; No. 1404 of 1857,
that when waste gases from blast furnaces are used therewith without
previous purification, the dust passing into the stoves with such gases is
deposited in the "chequered work" inside the regenerators and thus
becomes very detrimental to the perfect action of the stoves, and we
have found that the arrangements of "fire-bricks" and " perforated
tiles or blocks" forming the "chequered work," as shewn and described
in the above-named. Specification, and hitherto employed in the said
hot-blast stoves do not admit of being effectually cleaned out by a

page_text: brush or cleaning instrument as there is not sufficient room to pass
a brush or cleaning instrument through the perforations in the
"perforated tiles or blocks" even without taking into account the
slight irregularities that always occur in brickwork, or the fact of
the tiles or blocks moving somewhat relatively to each other from
expansion and contraction by heat, but even had it been possible to do
so the extreme amount of labour caused by separately manipulating
twenty-one to forty-eight holes in every "perforated tile or block"
filling the large regenerators required for hot blast stoves would have
rendered any such mode of cleaning entirely abortive and uneconomical,
and it has therefore been found in practice absolutely necessary in
cleaning out a stove to take out the whole of the fire-bricks or
"perforated tiles or blocks" forming the "chequered work," thereby
entailing, very considerable expense and great delay.
Now our Invention has for its object so to construct the " chequered
work," or filling in of the stoves, that while the current of air or gas
passing through the same is effectually broken up or disturbed and
brought into contact with extended heated or heat absorbing surfaces,
yet the passages of the filling in are so formed that a brush or cleaning.
instrument can readily be passed down the same for effectually cleaning
them from the deposit. Such filling in can be constructed in a great
variety of ways for the purposes of this Invention, thus in one arrange-
ment it consists of vertical continuous passages or flues of a circular,
square, or polygonal transverse section, on the side surfaces of which
are formed either helical, inclined, vertical, or horizontal projecting ribs
or fillets, against which the current of air or gas in passing up or down.
is caused to impinge, whereby it is disturbed or turned over so as to
bring the central portion of the current to the outside, such projections
still leaving ample room to pass the rod of the brush or cleaning
instrument through. When horizontal or somewhat inclined projections
are used these may be arranged either alternately on opposite sides so
as to form, more or less, a zig-zag passage, or they may be made
opposite each other so as to produce alternate enlargements and con-
tractions of the passages. When helical projections are used these
may be in lengths, turning alternately right-handed and left-handed, or
in place of such helical and other projections the entire passage may be
made of a helical or twisted or zig-zag form or with alternate enlarge-
ments and contractions, always so arranged, however, that a central
straight passage shall be left for the rod or suspending cord of the

page_text: cleaning brush or instrument. Again, the filling in may be built up
of superposed layers of bars or slabs arranged to cross each other at
right angles, or at any other angle, but so that the bars or slabs of the
several layers lying in the same direction are not "placed over the
spaces between them," or made to break joint as heretofore and as
described in the before-mentioned Specification, but are arranged
vertically one above the other so as to leave vertical spaces passing
right through all the layers through which the brush or cleaning
instrument may be passed. Or the bars or slabs may be so arranged as
to leave slanting or inclined passages in place of vertical ones for passing
the brush or cleaning instrument down.
•
In some cases, when it is wished to reduce the friction of the air
through the stoves to a minimum, and it is therefore not considered
desirable to obstruct the air very much by the introduction of consider-
able projections into straight passages we purposely build the filling-in
or brickwork, so as to produce rough surfaces sufficient to cause the
requisite disturbance in the air, but in such cases we provide ample
room in the passages for large and efficient brushes or cleaning instru-
ments being used, so that the surfaces may be kept particularly clean
in order to cause the communication of the heat to take place with
sufficient rapidity. Or we construct one deep and narrow spiral passage
(or it may be portions of concentric circles leading into each other),
commencing at the central shaft and winding round and round to the
outer circumference of the stove, which passage may be cleared out
through apertures in the top and bottom. Or we construct a number
of helical or screw-like passages going round and round the central
shaft of the stove similar to spiral staircases and of a sufficient size to
allow of a boy or man passing through them for cleaning them out,
while loose bricks or slabs of fire-brick may be placed at intervals in the
passage by the boy or man in order to break up the current of air or
gas; or the passages in place of being spiral may be horizontal and
circular, or segmental on plan with steps or drops from one layer to the
next, and at such steps or drops we sometimes form large man-holes or
pits, the better to enable a man to clean out the passages with a brush
or other cleaning instrument, in which cases the passages need not be
made large enough to admit a man but must be amply large enough to
admit a good strong brush or other cleaning instrument and also allow
room for a considerable deposit of dust; or similar passages, in place
of passing round and round the central shaft, may pass backwards and

page_text: forwards in the stove dropping at each end one step to the next layer of
passages, which passages can be conveniently closed at one end by loose
bricks put into their places by a man in the vertical flue, up which the
inflamed gas usually passes.
One plan for dislodging dust from the stove, which we sometimes
employ, consists in exploding a small quantity of gunpowder or other
explosive compound in the lower or upper portion of the stove, but by
preference in the lower portion; the powder should be confined in a
stout cartridge or maroon, so as to explode with some violence, thereby
creating such a concussion in the air as to throw off a large quantity
of the dust that adheres to the side surfaces and from any of the flat
surfaces,
Another part of our Invention consists in employing in place of or in
conjunction with a brush or other cleaning instrument for cleaning out
the air passages through the filling in a blast pipe or pipes for air or
steam, or both, so arranged as to be applicable for blowing through the
several passages one after the other or through several at once, so that
the energy of the blast may not be lost over the whole area of the filling
in, but may be concentrated as much as necessary to remove dust or
deposit. One pipe arrangement suitable for the purpose consists in a
vertical pipe and stuffing box at the top of the stove, and having an
arm or arms attached to its lower end, carrying blast jets or nozzles to
blow down the passages, the whole being rotated from the top after its
introduction into the top part of the stove through the man-hole, in
order to vary the radius at which the jets act; the arms are provided with
elbow pipes that can open or close so as to increase or diminish the
distance from the centre, or the arm or arms are caused to slide with
telescopo joints in or out. The apparatus may be put together by intro-
ducing the arm or arms at a small door at the side of the stove and
screwing them into the vertical pipe or it into them. Also flexible
pipes or pipes with joints in them are to be used in the bottom part of
the stove for cleaning, and the steam or air valve may be arranged to
be opened very suddenly so as to give sudden puffs of air or steam. In
place of or in addition to the above-named pipes for blowing out dust
other pipes are introduced when necessary through holes in the top of
the stove, and are thrust down as far as may be necessary in order to
remove dust, there being provided openings or jets in the sides of such
pipes, so that on a blast of air or steam or both being applied through

page_text: the pipes it may take effect at the level at which the jet or jets lappen
to be, the pipes being raised and lowered and turned round as necessary,
or they may be thrust down each passage separately to blow the dust
out, in which case they can best be manipulated by a man in the stove,
the air or steam being supplied through a flexible pipe..
Having thus set forth the nature of our Invention, we will now
proceed more particularly to describe the manner of performing the
same, for which purpose we shall refer to the accompanying Drawings,
which serve to show some of the various arrangements. by which our
Invention may be carried into effect.
66
'
Figures 1 and 2 on Sheet I. shew respectively a plan and vertical
section of a very convenient and effective mode of constructing the
filling in of the stoves according to our present Invention. It consists.
of a number of superposed layers of fire bricks or slabs A1, A2, A³, set
on edge and so arranged as to form in each layer a series of cells or
boxes," each such cell or box being closed in on all four sides, while
the cells of the one layer (A²,) though situated immediately over those
of the layer beneath it (A¹) are shifted somewhat in a diagonal direction,
so as to cause two sides of the cells of the lower layer to project beyond
the same sides of the upper cells, while the two opposite sides of the
upper cells are made to project beyond the same sides of the lower cells.
Thus a series of continuous separate zig-zag passages B, B, are formed
which cause an effectual disturbance or breaking up of the current of
air or gas passing through them sufficient to bring every portion of such
current in contact with the extended heating or heat aborbing surfaces,
while at the same time a sufficiently clear vertical space is left right
through the passages to allow of an efficient brush C or blast of steam
or air being passed through them for removal of the dust deposited
therein by the blast furnace gases. It will be seen that cách brick
or slab is held securely in position between the two ends of the adjacent
bricks, so that when once placed in position there is no possibility
of any derangement of the layers occurring. The lowest layer A' is
made to rest upon an iron grid D, forming cells corresponding in size and
position with the cells of the layers but also shifted somewhat to one side
of these.
Figure 3, Sheet I., and Figure 4, Sheet II., show respectively a part
sectional elevation and part sectional plan of a stove E to a smaller scale
in which the gases in combustion pass up into the chamber E' through

page_text: a central shaft or passage, and then down through the passages in the
filling in, so as to heat the brickwork of which they are formed. The
blast of air, steam, or gas to be heated passes up through the passages of
the filling in after the brickwork has been heated and the gas for com-.
bustion has been shut off; such blast then passes down the central shaft
or passage to the outlet hot blast valve.
In these Figures the filling in is arranged as just described, and they
show arrangements of pipes for the introduction of jets of steam or air
into the passages for clearing out the dust. Such pipes may be intro-
duced as at F, F', through side apertures G, G, (ordinarily closed with a
plate) the ends f of the pipes being bent down so as to deliver the blast
vertically into the passages. They are moved about by the operator so
as to bring the nozzle of the pipe successively over cach passage, to;
facilitate which motion the nozzle of the pipe is provided with a rounded
surface, as shewn, and rollers H are provided on which the outer end of
the pipe rests. Four such side apertures would be found sufficient to
gain access to all the passages of the stove, and for conveniently reaching
those passages situated immediately against the sides of the stove curved
pipes may be employed with advantage. Or such steam or air pipes.
may be introduced through a central aperture I in the top of the stove,
as at J, for which purpose a vertical pipe J¹, into the upper end of
which the steam or air blast is introduced, is connected. to the pipe J
by an elbow joint, and is carried by a frame K in which it is capable
of being both raised and lowered and made to revolve by suitable.
gearing, whereby the nozzle of the pipe may be moved both in a radial
direction to and from the centre of the stove, and in a circular direction
so as to bring it over each of the passages in succession.
Another arrangement of cleaning pipes consists of a vertical central
pipe capable of turning and connected to a horizontal pipe provided
either with a sliding telescopic pipe or an elbow pipe, so that it may be
altered in radius to blow down every passage. Pipes may be applied*
from below to blow up the passages if preferred, and this can be con-
veniently done by a man entering the space below the filling in, as such
space is generally cool and can always be quickly cooled down by cold
blast, in such case there is a guard or screen like an umbrella fixed to
the pipe to keep the dust from falling on the man. In some cases it
may be convenient to perform the blowing and brushing operations,
simultaneously, for which purpose the end of the blast pipe that is..

page_text: ་
passed down the passages may be provided with a brushing or scraping
surface.
Figures 5 and 6, Sheet II., shew respectively a plan and vertical
section of another arrangement of the filling in. Here as in the first
arrangement separate continuous passages B, B, are formed by super-
posed cellular layers of fire-bricks A1, A2, A3, but in place of cach layer
being shifted diagonally over the one below, they are only shifted to one
side of each other so as to form alternate projections on two sides, while
the other two sides of the passage have an unbroken surface all the way
through as shewn in plan.
Figures 7 and 8, Sheet II., show a sectional plan and a vertical
section of an arrangement in which the separate continuous passages
are formed of lengths of fire-brick pipes or tubes L, L, cach length
having helical projections 1, 1, running in a contrary direction to
those of the lengths situated above and below it, so that any portion
of the air or gas passing up or down in a helical direction along such
projections of the one length of pipe is made to travel in the contrary
direction in passing against the projections of the next length, whereby
the current of air or gas' will be effectually disturbed so as to bring
all portions thereof into contact with the surfaces of the passages.
The cleaning out of these pipes may be very effectually performed
by the brush by causing the same in its descent or ascent through
the central space to turn in a direction corresponding to that of the
helical projections as it passes through the the successive lengths of
pipes. The before described passages may be made to act efficiently
if provided with only slight irregular projections or roughnesses, or even
if formed without either projections or roughnesses, as it must be borne
in mind that owing to the large collective area afforded by all the
passages of the filling in as compared with the area of the inlet pipe the
air or gas ascends or descends through them at such a slow speed that a
most perfect stratification of the air or gas according to different
temperatures is attained, effectually preventing any rushing up of a
central column of unequally heated air or gas, the friction of the air or
gas while moving at such a slow speed against even perfectly smooth
surfaces being sufficient to disturb the current so as to bring all portions
thereof successively in contact with the sides of the passage.
Figures 9 and 10 shew respectively a plan and vertical section of an
arrangement in which the filling in is built up of superposed layers of

page_text: fire-bricks, bars, or slabs A³, A³, A³, arranged to cross each other, but so
that the bricks of the several layers running in the same direction are
arranged vertically over each other, and not made to break joint as
heretofore, whereby vertical spaces B, B, are left passing right through-
all the layers through which a brush or blast of air or steam may be
passed. As however in this arrangement no separate enclosed passages.
are formed, the use of a blast of air or steam for cleaning purposes.
would not be so advantageous as in the previous arrangements.
Figures 11 and 12, Sheet I., shew respectively à vertical section and
a sectional plan of a construction of regenerative hot blast stove having
a deep and narrow spiral or volute passage M, communicating at the
inner end with the central shaft N and inlet passage O, P, for gas
and air for combustion and hot blast outlet Q', while the outer end.
communicates with the outlet aperture R to the chimney and air inlet
Q for blast, so that the gas in combustion and the blast pass through:
such spiral passage alternately in contrary directions, the former giving.
out the heat to and the latter taking up such heat from the walls of,
the passage. Stoppered apertures S, S, are provided in the top of the.
stove through which brushes or blasts of air or steam may be introduced
for clearing out the dust. Or in place of such spiral passage one or
more helical or screw-like passages may be constructed as herein-before.
described.
Figures 13 and 14 (Sheet I.) shew respectively a vertical section and
sectional plan of an arrangement in which a number of layers of
narrow horizontal passages T, T, T¹, are constructed one above the other
between division walls U, U, each passage being made to communicate
at opposite ends with the passages above and below it through apertures
V, V, formed in the horizontal partitions, so that the hot gases entering
through the vertical passage W, and passing into the top layer of
passages Tare caused to descend consecutively through all the layers
on their way to the outlet X, while the air is caused to ascend through
them in like manner in the contrary direction alternately with the gas
in combustion. Stoppered apertures Y, Y, are formed in the stove at
the ends of the passages T, as also in the top of the stove for the
introduction of brushes or steam or air pipes for clearing out the
deposit. Although not described in detail in each arrangement it is to
be understood that in every case the stove is to be enclosed in an air-
tight wrought iron or cast iron case and is to be provided with valves
to the inlets and outlets.

page_text: It will be readily understood that as by the facility afforded by our
present Invention for frequently clearing the passages of regenerative
hot blast stoves from deposit we are enabled to maintain more effective
heating surfaces in the stoves than heretofore, and therefore the tem-
perature of the blast attainable by our improved stoves will be higher and
consequently a greater saving of fuel in the blast furnace attained. It has
in fact, been proved by experiment that the. raising of the temperature
of the blast from 800° Fahrenheit, up to about 1440° effects a saving of
coke in the blast furnace of about 8 hundredweight per ton of iron made,
and this saving may by the use of the present Invention be further
increased, as a temperature of 1500° or more is easily attainable thereby.
Having thus described the nature of our Invention, and in what
manner the same is to be performed, we wish it to be understood that
we do not limit ourselves to the precise arrangements for carrying the same
into practice herein-before described with reference to the accompanying
Drawings, as these may be variously modified, and various other forms
of passages be adopted for the filling in as herein-before stated without
departing from the nature of our Invention, also we are aware that
regenerative hot blast stoves have been constructed with a vertical zig-
zag or serpentine passage, as described in the Specification to Whitwell's
Patent, No. 2897. of 1865, and we do not therefore claim such an arrange-
ment as part of our present Invention, but what we claim is,-
"
First. Constructing the filling in of regenerative hot blast stoves of
a large number of separate vertical or nearly vertical passages of
sufficient size to allow of a brush or blast of air or steam being passed
through them for the removal of deposit therefrom, whilst at the same
time the passages, so, formed with extended surfaces effectually absorb
and give out the heat from and to the gases and air passing through
them, substantially as herein-before set forth.
Second. Constructing the filling in of regencrative hot blast stoves of
separate vertical or nearly vertical passages, so formed with projections,
contractions, roughnesses,, or equivalent. contrivances, that while the
currents of air or gas in passing through the passages are effectually
disturbed and brought, into contact with extended heated or heat
absorbing surfaces, yet these passages readily allow of a brush or
other cleaning instrument, or a blast of steam or air being passed
through them, for removing the deposit, substantially as herein-before set
forth.

page_text: Third. Constructing such aforesaid separate vertical passages in the
manner and of the various forms hercin-before described with reference
to the accompanying Drawings, or in any manner substantially the same,
for the purpose of effectually absorbing and giving out the heat from
and to the currents of gas and air, and yet allowing of the passage of
a brush or blast of steam or air through them for the removal of the
deposit.
Fourth. Constructing the filling in of superposed layers of bars or
slabs, so arranged as to leave vertical spaces passing right through
all the layers, through which brushes or blasts of air or steam may be
readily passed, substantially 'as described with reference to Figures 9 and
10 of the Drawings.
Fifth. Constructing regenerative hot blast stoves with a continuous
spiral or volute passage with or without projections, commencing at the
centre of the stove and terminating at the circumference thereof, sub-
stantially as herein-before described.
Sixth. Constructing regenerative hot blast stoves with one or more
helical or screw-like passages passing from the lower end of the stove
to the upper end, substantially as berein-before described.
Seventh. Constructing regenerative hot blast stoves with a number
of superposed passages arranged to intercommunicate alternately at
opposite ends by means of vertical passages, substantially as described.
Eighth. The employment of blasts or jets of air or steam or both for
the removal of the deposit in the passages of regenerative hot blast stoves,
substantially as set forth.
Ninthly. The various before described. arrangements of blast pipes
for the introduction of jets of air or steam for clearing out the deposit
from regenerative hot blast stoves.
In witness whereof, I, the said Edward Alfred Cowper, have here-
unto set my hand and seal, this First day of July, in the year of
our Lord One thousand eight hundred and seventy.
EDWARD ALFRED COWPER. (L.S.).