AN IMPROVED GAS FURNACE
Year: 1867

page_text: LETTERS PATENT to Richard Howson, of Middlesbro'-on-Tees, in the
County of York, Engineer, for the Invention of "AN IMPROVED GAS
FURNACE,"
Sealed the 5th May 1868, and dated the 15th November 1867.
PROVISIONAL SPECIFICATION left by the said Richard Howson at
the Office of the Commissioners of Patents, with his Petition, on the
15th November 1867.
I, RICHARD Howson, of Middlesbro'-on-Tees, in the County of York,
Engineer, do hereby declare the nature of the said Invention for "AN IM-
PROVED GAS FURNACE," to be as follows:-
I construct the furnace with a hollow hearth somewhat like that of an
ordinary reverberatory furnace (but by preference of a circular shape in plan),
and with a flue or flues leading therefrom to a chimney. In the crown of this
furnace immediately over the hearth I insert a pipe or casing, by means of
which the gas is introduced into the furnace through one ormore perforations
in the lower part of the said casing, in which I place one or more nozzles,
through which air is blown underpressure through the aforesaid perforations.
The effect of this arrangement is that each jet of air causes an induced
current of gas to be projected downwards upon the materials lying in the
[Price 8d.1

page_text: hearth, while the air is at the same time intimately mixed with the gas,and the
result is an intense temperature in the chamber of the furnace. I moreover
employ valves with haudles which are easy of access for the purpose of
regulating the supplies of air and gas, and I also make the nozzles or jet
apparatus readily adjustable by handles upwards and downwards. By these
means I am able to produce an oxidising or reducing flame at will and to
raise or lower the focus of combustion to any point desired. The gas may.be
generated by any of the known plans inone or more generators either attached
to the furnace or separate from it, and I prefer that the air should be heated
by means of the waste heat of the chimney, It is not necessary that the gas
and air should be introduced immédiately over the centre of the hearth so as
to be projected vertically downwards; they may be introduced more or less
at oue side and projected in a slanting direction, and there may be more than
one point of introduction if so desired. The hearth also instead of being
circular may assume other shapes. This furnace is adapted to the manufacture
of steel and wrought iron, and is also applicable to other metallurgical
operations.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
•
by the said Richard Howson in the Great Seal Patent Office on the
14th May 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
Howson, of Middlesborough-on-Tees, in the County of York, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Fifteenth day of November, in the year of our Lord
One thousand eight hundred and sixty-seven, in the thirty-first year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto
me, the said Richard Howson, Her special license that I, the said Richard
Howson, my executors, administrators, and assigns, or such others as I,
the said Richard Howson, my executors, administrators, and assigns, should
at any time agree with, and no others, from time to time and at all times
thereafter duringthe term therein expressed, should and lawfully mightmake,
use, exercise, and vend, within the United Kingdom of Great Britain and
Ireland,the Channel Islands, and Isle of Man, an Invention of "AN IMPROVED
GAS FURNACE," upon the condition (amongst others) that I, the said Richard
Howson, by an instrument in writing under my hand and seal, should par-

page_text: ticularly describe and ascertain the nature of my 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 Patent.
NOW KNOW YE, that I, the said Richard Howson, do hereby declare
the nature of my said Invention, and in what mauner the same is to be
performed, to be particularly described and ascertained in and by the following
statement and accompanying Drawings (that is to say):-
I construct the furnace with a hollow hearth somewhat like that of an
ordinary reverberatory furnace with one or more flues leading to a chimney.
In the crown of the furnace immediately over the hearth I place a pipe or
casing, by means of which the gas is introduced through one or more perfora-
tions opening downwards, and in the same casing I place one or more nozzles,
through which air is blown under pressure through the aforesaid perforations.
The effect of this arrangement is that each jet of air causes an induced
current of gas to be projected downwards upon the material lying in the
hearth, while the air is at the same time intimately mixed with the gas, so
that the result is the production of an intense heat in the chamber of the
furnace.
The arrangement will be clearly understood by reference to the annexed
Drawings.
Fig. 1 represents a sectional elevation of a furnace adapted to the manu-
facture of cast steel.
a is the chamber, and 6 the hearth; immediately above the chamber is
placed the casing c, into which the gas is introduced through the pipe d. In
the same casing a number of nozzles (e)are placed, through which air is blown
downwards into the chamber a, such air being forced under pressure and
conducted to the nozzles (e, through the pipe (e¹). It is evident that as the
gas enters the furnace by the natural draught of the chimney, the rapidity of
its motion will be materially increased by the inductive power of the jets, and
it will also be clear that as the air and gas are by this means intimately
mixed, the combustion will be very rapid and intense with a short flame
tending to a focal point after the manner of a blowpipe flame. In order to
apply this flame to advantage the nozzles(e) require to be placed in oradjusted
to such a position that the point of greatest intensity is at or about the upper
surface of the metal in the hearth, and the nozzles may be made adjustable
by hand, as shewn in Fig. 5, if required (the part (e) being capable of sliding
up and down in the casing (o)), although this is not in all cases necessary.
With regard to the number and arrangement of the nozzles (6) and the

page_text: general form of what may be called the burner, these may be varied in many
ways according to circumstances.
Fig. 6 shews in plan the simplest form of burner, consisting of an outer
case (c) for the gas, with a single central pipe or nozzle (e) for the air
jet; Fig. 7 shews a circular casing (c) with a group of nozzles (e);
Fig. 9 shews a rectangular casing (c) with also a group of nozzles (e).
Fig. 8 is similar to Fig. 7 with this exception, that instead of the nozzles
all blowing through one opening each nozzle has a separate concentric
opening. I may here observe that I do not confine myself to a circular
nozzle, as they may be made in the form of long narrow slits so that the air
and gas will combine in thin sheets. The shape of the hearth (6) will of
course to a certain exteut correspond to the shape of the burner. For instance,
with a circular burner the hearth will approach to a circle in plan, and will be
of a rectangular form when the burner is rectangular,but I do not adhere to
any particular form of either hearth or burner.
It is an important feature of my Invention that the burner should be so
arranged that the flame may be directed more or less downwards upon the
surface of the metal in the hearth, and I have hitherto described it with
reference to Fig. 1, in which the burner is shewn central with the hearth and
vertically above it. This is the arrangement which I at present prefer with
two flues (¹) leading opposite ways, but a similar relative position of burner
may be used with only one flue (a¹), as shown in Fig. 3. The burner may
also, if desired, be placed at an angle, as in Fig. 4, and there may be more than
one burner to one furnace, as, for instance, in Fig. 2, where two burners are
shewn inclined to each other. I have hitherto described the inuer jet of each
burner as the air jet surrounded by the gas, but this may be reversed without
departing from my Invention, the inner jet may be gas surrounded by air, and
either or both may be supplied to the burner under pressure. The mode of
generating the
gas does not form any part of my Invention, inasmuch as any
combustible gas may be employed, such as coal gas made in retorts in the
ordinary manner, the mixed gases arising from the imperfect combustion of
coal, or the waste gases of blast furnaces. The gas generator may also be
either attached to the furnace or separate from it. Before however it is
introduced into the furnace it will tend to economy and increased effect to
heat it by passing it through pipes place in the flues, so that it may absorb a
portion of the waste heat of the furnace. I also prefer to heat the air in the
same manner.
One arrangement for effecting this is shewn in Figs. 1 and 2, where fand f¹
are cast-iron pipes suspended in the flue (a2), and exposed to the action of

page_text: the heated products of combustion. Inside the pipes (f and f') are other
concentric pipes (g and g¹), with their open ends downwards. The gas and
the air pass along their respective pipes in the direction of the arrows, and
become heated in their passage through the annular space between the two
pipes. The waste gases after leaving the flues (a) pass along the flues (a³),
through the central flue (h) to the chimney. In the Drawing is only shewn
one set of heating pipes for the gas and one for the air, but it will be readily
understood that they can be duplicated to any extent. I do not however
adhere to this particular form of heater, as it is obvious that other forms
might be adopted which would answer the purpose sufficiently well, neither do
I adhere to cast iron as the material of which the heaters are to be made, as
fire-clay or fire-brick might be employed with good effect. The air and gas
may also be heated by means of a "Siemens' regenerator" arranged in
connection with the furnace. In order to regulate the respective volumes of
air and gas entering the furnace, I employ valves k and k¹, which may be of
any ordinary construction, fitted with screws or handles easily accessible to the
attendant, who by this means can produce an oxydising or a reducing flame at
will. The position of the burner in the roof of the furnace has a tendency to
keep the crown cool, but water boshes may be used to effect this object where
necessary as is well understood.
The furnace as above described is especially adapted to the manufacture of
cast steel, but without altering any of the essential features of the Invention,
it is also applicable to a variety of other metallurgical operations, such as
puddling, the melting of metal generally, and the reduction of metal from
their ores.
Having now described the nature of my Invention, and the modes of carrying
it into effect, I would have it understood that I claim as my Invention,-
Firstly. The use of a burner whereby gas and air may be intimately mixed
and injected into a reverberatory or other similar furnace, substantially as
herein-before described.
Secondly. The system or mode of injecting mixed gas and air downwards
from the crown of the furnace, substantially as herein-before described and
illustrated by the Drawings.
Thirdly. The heating of the gas and air supplied to burners of the character
referred to in my first claim by the waste heat of the furnace.
Fourthly. The arrangement of an air and gas burner so that the position
of the point of the greatest intensity of the flame produced may be regulated
or adjusted, substantially as herein-before described and illustrated by Fig. 5
of the Drawings.

page_text: Fifthly. The use of any suitable valves for regulating the relative
quantities of gas and air to burners of the character referred unto in my
first claim.
In witness whereof, I, the said Richard Howson, have hereunto set my
hand and seal, this Twelfth day of May,One thousand eight hundred
and sixty-eight
RICHARD HOWSON. (L.S.)