IMPROVEMENTS IN HOT AIR STOVES FOR HEATING THE BLAST FOR BLAST FURNACES
Year: 1880

page_text: LETTERS PATENT to Thomas Wardle and Charles Lister, both of the Town of
Middlesbrough on Tees, and County of York, Blast Furnace Builders, for an
Invention of " IMPROVEMENTS IN HOT AIR STOVES FOR HEATING THE BLAST
FOR BLAST FURNACES."
PROVISIONAL SPECIFICATION left by the said Thomas Wardle and Charles
Lister at the Office of the Commissioners of Patents on the 24th September
1880.
THOMAS WARDLE and CHARLES LISTER, of Middlesbrough on Teos, in the County
of York, Blast Furnace Builders. "IMPROVEMENTS IN HOT AIR STOVES FOR
HEATING THE BLAST FOR BLAST FURNACES."
Our Invention has reference to that class of stoves or ovens for heating the blast
for blast-furnaces called regenerative or fire brick stoves. In using these stoves
two or more similar stoves are employed, which are alternately heated by burning
gas supplied from the blast furnace or other source of heat, and the blast to be
heated is alternately directed into and is caused to pass through these stoves, and is
in this manner heated. Each stove generally consists of a vertical cylindrical iron
casing lined with fire brick or other refractory material, the interior containing an
arrangement of the same material in the form of parallel walls with spaces or
passages between (or other open brickwork), so that this material can be heated
by the burning gas pervading these spaces or passages, and afterwards by shutting
and opening suitable valves, the blast to be heated is passed through the same
spaces or passages.
The present form and construction of stoves have several disadvantages, as
follows: To secure effective heating surface the stove has to be raised to a height,
which increases the cost of erection in proportion to the height the material
composing it has to be raised; the necessary thickness of walls and strength of
material needed to sustain the superincumbent pressure; if the roof is flat the
number of girders employed to resist internal pressure of blast is very expensive;
if dome shaped, the lining of which is costly; the proportionate height of chimney
required to produce sufficient draft; the difficulty of cleaning such high erections.

page_text: On the other hand, if the height is lessened by increasing the horizontal area, then
the heating is irregular; further, in some cases the hot blast valve and gas valvo
are liable to fracture from a deposit of mud left by the water running through
them for their protection. The above disadvantages interfere with the usefulness
of this important class of stoves, and render them unnecessarily expensive.
Now our Invention has for its object the remedying of these defects, and consists
in reducing the height to one half it would otherwise be, to secure the same
amount of heating surface by making each stove of two vertical cylindrical iron
casings, connected at top by a horizontal cylindrical iron casing of the same
diameter as the vertical casings; this borizontal piece forms the roof of the stove,
and contains the openings for cleaning and for safety valves. From the cylindrical
form of this roof neither girders nor the dome shape is required. The interiors of
the vertical casings and the horizontal connection are lined with suitable fire brick ;
the vertical portions of the stove contain the walls or other open fire brick work,
over which the ignited gas and afterwards the blast pass as has been described.
The gas and hot blast valves are connected with one vertical casing, and the cold
blast and chimney valves are connected to the other vertical casing of the stove.
The gas admitted by the gas valve is ignited in the first vertical portion of the
stovo, traverses the passages in the brickwork, then passes through the horizontal
connection into the second vertical portion and traverses the passages in its
brickwork, the products of combustion then pass through the chimney valve into
the chimney.
When the stove has thus been sufficiently-heated the cold blast admitted by the
cold blast valve passes over the heated surfaces of the brick work and becomes hot
-blast, and-so-passes by_the_hot_blast valve into the blast furnace. It will thus be
understood that the ignited gas passes from one vertical portion of the stove-into-
the other vertical portion by means of the horizontal-connection, and afterwards_
the blast in like manner but in opposite direction. There are also suitable valves
for the admission of air in each vertical portion for the proper combustion of
the gas.
In order to explain our improvement in the gas and hot blast valves it must be
understood that in these valves, generally in use at present, the water for their
protection is conducted into them by an internal pipo which passes down a hollow
spindle connected to the valve, and returns from the valve by the space between
this internal pipe and the valve spindle. This arrangement does not prevent the
deposit of mud that endangers the safety of the valve. Our method of preventing
this is to make the hollow spindle in two parts, fixing one portion to the upper and
other portion to the under side of the valve. The upper part of this hollow valve
spindle passes through a stuffing box and gland in the upper cover of the valve
casing, and in like manner the under part passes through a stuffing box and gland
in the under cover of the valve casing. These stuffing boxes and glands act as
guides to the raising and lowering of the valve. The valve seat is also protected
by having water conveyed round it by means of a wrought iron pipo imbedded in
the seat when cast. The water is conveyed to the seat and valve in the following
manner-1st, by a pipe which connects the water supply with the pipe in the
seat, and from the seat by a pipe connected with the upper part of the valve
spindle; part of this connection is by a flexible pipe of vulcanized rubber or other
flexible material so as to allow the valve to be raised or lowered on its seat; the
water is thus conveyed to the interior of the valve, and from the valve thence by
the under portion of the valve spindle; the mud conveyed by the water is thus
carried away at once and the deposit prevented; this improvement includes all
valves in which a current of water is employed for their protection in any part of
the stove.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Wardle' and Charles Lister in the Great Seal Patent Office
on the 3rd March 1881.
THOMAS WARDLE and CHARLES LISTER, both of the Town of Middlesborough on
Tees, in the County of York. "IMPROVEMENTS IN STOVES FOR HEATING THE
BLAST FOR BLAST FURNACES."
This Invention has for its object improvements in stoves for heating the blast
for blast furnaces, and has reference to the construction of that class of stoves or
ovens used for heating the blast for blast furnaces called regenerative or fire brick
stoves, where the interior of the stove or oven consists of an arrangement of
brickwork or other refractory material heated by gas. In using these stoves two
similar stoves are employed, which are alternately heated by the combustion of the
gas therein supplied from the blast furnace or other source, and the blast to be
heated is alternately directed into and is caused to pass through these stoves, and is
in this manner heated. Each stove generally consists of a cylindrical iron casing.
lined with fire brick, the interior of which contains an arrangement of brickwork
in the form of parallel walls with spaces or interstices between them, or other
open brickwork, so that this material can be heated by the burning gas passing
over its surface and pervading its spaces or interstices, and afterwards by shutting
and opening suitable valves, the blast to be heated is passed over the same surfaces
and through the same spaces or interstices.
In the existing form and construction of stoves of this kind there are several
disadvantages, viz., to secure effective heating surface, the stove has to be
raised to a height, which increases the cost of erection in proportion to the height
the material composing it has to be raised; if the roof is flat the number of girders
required to resist internal pressure is expensive; the necessary thickness of
walls and strength of material needed to sustain the superincumbent pressure;
the height of chimney required to cause sufficient draught; the labour and
difficulty in cleaning such high erections. On the other hand, if the height is
lessened by increasing the horizontal area, then the heating is irregular and greater
area required for the erection. The dome shaped form of roof is also inconvenient
to line and therefore adds to the cost. Another objection is the intricate valve
gearing; and, further, gas and hot blast valves are liable to fracture from a deposit
of mud left by the water used for their protection. The above objections together
interfere with the usefulness of this important class of stoves and cause them to be
unnecessarily expensive.
Now our Invention has for its object the remedying of these defects, and consists
in reducing the height by making each stove of two vertical cylindrical iron
casings, connected at top by a horizontal cylindrical iron casing of the same
diameter as the vertical casings, this horizontal piece forming the roof of the stove
and also the openings for cleaning; from the cylindrical form of this roof girders are
not required. The interior of these vertical casings and also the horizontal
connection is lined with fire brick or other suitable material, and contains the open
brick work in the form of vertical parallel walls with spaces between them, or
5 other arrangement of refractory material containing interstices, over the exposed
surfaces of which the ignited gas passes, and the interior of the stove thus becomes
heated to the temperature required. The casing which contains the valves for the
entrance of the gas, and also the casing which contains the valve for the exit of
the hot blast are connected to the first vertical portion of the stove; and the valve
through which the products of combustion pass to the chimney, also the valve
which admits the cold blast, are connected to the second vertical portion. The
casings containing these valves are suitably lined with fire brick. The gas admitted

page_text: by gas valve is ignited in a part of the first vortical portion of the stove called the
combustion chamber, then traverses the open brick work or spaces between the
parallel walls or other interstices, and passes through the horizontal connection into
the second portion, and then passing over the interstices contained in this portion
passes through the chimney valve into the chimney. This chimney may either be
attached to each separate stove or the chimney valve may open to a flue
leading to a common chimney serving for several other stoves or furnaces. When
the interior of the stove has thus been sufficiently heated, the gas and chimney
valves are closed, and the cold and hot blast opened; the blast then passes over the
beated surfaces absorbing their heat, and becomes hot blast, then passes out by the
hot blast valve into the blast furnace. There are also suitable valves for the
admission of air, which air passes through flues formed in the brick work of each
portion of the stove, and mixes with ignited gas in its passage, and so perfect
combustion is obtained. There are in different parts of the stove, doors or valves
through which it can be cleaned of the dust which is carried in by the gas from the
furnace.
Although in our Provisional Specification we have described an improvement in
valves, we have since discovered a better means for effecting the same object, and
that many forms of valves may be adapted to the purpose of our Invention, such as
where water is not used internally in the valve, it is made with a double mitre, and
in connection with this valve are two valve scats. The lower mitre of the valve is in
contact with the lower seat when the valve is shut, and the upper mitro is in
contact with the upper seat when the valve is open; these seats have water
running through thein for their protection, and when the valve is in contact with
these seats, the mitres on the valve are protected by conduction through the metal à
And in order-that our said Invention may be. properly understood, we will now
proceed to describe the same by reference to the annexed Drawings, wherein similar
letters of reference indicate similar parts in both the Figures. Fig. 1 is an
elevation of the stove. A, A, is the first vertical portion; B, B, the second vertical
portion, and C, C, the horizontal connection; D, D, are the doors in the roof for
cleaning, and E, E, the cleaning doors below; F and G are the casings which
contain the hot blast and gas valves respectively; H, the chimney valve casing
containing the chimney valve, which communicates with tho chimney I. This
chimney is secured to the stove by stays J', as shown. The valves in the casings
are raised and lowered on their seats by levers or other means in general use.
cold blast valve (not shewn in the Drawing) admitting the cold blast is connected
to the chimney valve casing at K. Fig. 2 is an end elevation.
The
The first vertical portion of the stove is divided into three parts or chambers by
vertical divisional walls similar to those now in use. The first chamber is the
combustion chamber, the second chamber contains three or several thinner walls,
and the third chamber also contains similar thin walls to the second chamber. The
second vertical portion is also divided into three parts or chambers by vertical
divisional walls; these chambers also containing several thin walls similar to the
thin walls in the first vertical portion of the stove. These thin walls are not built
up to the roof, but leave an open passage, and all of them have openings below.
The first divisional wall has no opening below, but has openings in the top
communicating with the second chamber. The second divisional wall has openings
below that communicate with the third chamber, but is built up to the roof at top;
and so in like manner in the second vertical portion the first divisional wall is
built up to the roof, but has openings below communicating with the next chamber.
The second divisional wall has an opening above that communicates with the last
chamber, but has no opening below. Thus the gas ignited in the combustion
chamber passes up this, then down the spaces between the thin walls in the second
chamber, then up the spaces between the thin walls in the third chamber, and then
by the horizontal connection into the second vertical portion of the stove, and upon
passing first down and then up, and down the spaces between the thin wall in the

page_text: chambers of that portion of the stove, ultimately pass on to the chimney by the
chimney valve, and when the stove has thus been heated to a temperature
sufficiently high, the blast is passed through in a similar manner to the gas, but in
a contrary direction, and so becomes heated before entering the blast furnace.
Having thus described the nature and object of our said Invention, wo would
observe in conclusion that we make no claim to the use of any particular valve, or
to the valve arrangements mentioned in our Provisional Specification, nor do wo
confine ourselves to the precise details or arrangements of brickwork, or valves or
doors for cleaning purposes herein before given, as various modifications of the
same may be adapted for the purposes of our Invention, but what we claim and
desire to be secured to us is,―
1. The general arrangement and construction of hot air stoves for heating the
blast for blast furnaces, substantially as herein before described and shewn on
Drawings, or any mere modification thereof.
2. The arrangement of a separate chimney to each stove or oven in lieu of the
common chimney or shaft now in use, substantially as herein before described and
shewn on Drawings.
3. The general combination and arrangement of parts together forming a duplex
hot blast regenerative stove, substantially as herein before described and shewn on
Drawings.
In witness whereof, we, the said Thomas Wardle and Charles Lister, have
hereunto set our hands and seals, this Twenty sixth day of January, in the
year of our Lord One thousand eight hundred and eighty one.
THOMAS WARDLE. (L.S.)
CHARLES LISTER. (L.S.)