Improvements in or relating to Puddling, Mill, Reheating, Forge, and other Furnaces.
Year: 1891

page_text: Date of Application, 20th Aug., 1891
Complete Specification Left, 23rd Oct., 1891-Accepted, 28th Nov., 1891
PROVISIONAL SPECIFICATION.
Improvements in or relating to Puddling, Mill, Reheating, Forge,
and other Furnaces.
We, JOHN JAMES NUTT, of Mount Pleasant, Spennymoor, Mill Manager, and
MARTIN LUTHER MULHOLLAND, of the Ferryhill Engine Works, West Cornforth,
Engineer, both in the County of Durham, do hereby declare the nature of this
invention to be as follows:-
Our invention relates to several kinds of furnaces, such as puddling, mill,
reheating, and the like furnaces to which it is more especially applicable but may
also be usefully applied to other furnaces, such as air furnaces for foundry purposes,
or the furnaces of boilers.
The object of our invention is to obtain a better combination of the elements of
combustion by which a saving of fuel is effected or inferior fuel can be used with
less smoke emitted from the chimney or uptake. Also in puddling and the like
furnaces we transfer the region of combustion from the front end of the furnace
above the furnace grate, towards the other end of the furnace above the hearth by
which the heat developed in the furnace is more completely absorbed by the process
in hand and is diverted in a corresponding degree from impinging upon and
destroying the roof of the furnace.
In describing the nature of our invention we will refer in the first place to its
application to a puddling furnace.
Puddling furnaces as ordinarily constructed consist of a grate and a hearth
separated by a furnace bridge. The fuel is placed on the grate through which air
is drawn to support combustion in the manner of an open fire.
What may be
termed the region of combustion occupies the space above the fire from which the
products of combustion are drawn under a low arch or roof to the flue at the stack
end of the furnace, consequently the combustion is most intense where it serves no
useful purpose and is correspondingly diminished when it approaches the hearth of
the puddling chamber added to which the wasted heat impinges upon and rapidly
destroys the furnace roof.
In a puddling furnace constructed according to our invention we divide the
furnace into two separate chambers by a transverse or diaphragm wall one of which
chambers serves as the puddling chamber and the other as a gas producer. The
puddling hearth is bounded or enclosed at one end by the usual furnace bridge with
cooling box; and the grate of the gas producer is also bounded or enclosed at one
end by a gas producer bridge; these two bridges extend transversely across the
furnace in the usual way and are parallel to the diaphragm wall which comes
between them forming a space for a grating between the said diaphragm wall and
the gas producer bridge leading through a series of openings into an air space
provided between the diaphragm wall and the furnace bridge on the other side into
which space the air is discharged from the cooling box in the furnace bridge at one
side of the furnace and a corresponding air hole is made on the other side of the
furnace.
The gas producing chamber is constructed and adapted to be worked on the slow
combustion principle, that is just sufficient air is admitted by forced drafts or jets of
steam into the chamber to support a slow combustion of the fuel, the gaseous
products of which pass off at a low temperature through openings in the diaphragm
wall into the puddling chamber where they encounter the air drawn in through the
grating on one side of the diaphragm wall into the air space on the other side.
The region of combustion of the gaseous products of the fuel is thus transferred

page_text: from the front end of the furnace to the puddling chamber itself where it is absorbed
without waste in effecting its intended purpose. A bright clear fire is kept burning
on the grate between the gas producer bridge.and the diaphragm wall by which the
air drawn into the furnace for the combustion of the gaseous products of the fuel is
heated this air is still further raised in temperature by absorbing heat from the
furnace bridge of the puddling hearth which is thereby cooled and preserved.
It will be observed that the part of the furnace shut off as a gas producing
chamber instead of including the region of the most intense combustion; in our
improved furnace remains at all times comparatively cool added to which it is
thought the currents of heated air which pass up through the air space to mix with
the gaseous products of the fuel attain sufficient force and velocity to penetrate
above these gaseous products which are forced downwards away from the roof and
onto the hearth of the puddling chamber. It will be readily understood from the
above description of our invention as applied to a puddling furnace how it would be
found equally advantageous to similar furnaces such as mill, reheating, or forge
furnaces. In the case of furnaces of a different type such as boiler furnaces, or air
furnaces, the above described mode of combining the elements of combustion will
be also applicable subject to such structural modifications as would not affect the
nature of our invention.
Dated this 19th day of Aroust 1801
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicants.
COMPLETE SPECIFICATION.
Improvements in or relating to Puddling, Mill, Reheating, Forge,
and other Furnaces.
We, JOHN JAMES NUTT, of Mount Pleasant, Spennymoor, Mill Manager, and
MARTIN LUTHER MULHOLLAND, of the Ferryhill Engine Works, West Cornforth
Engineer, both in the County of Durham, do hereby declare the nature of this
invention and in what manner the same is to be performed, to be particularly
described and ascertained in and by the following statement:-
Our invention relates to several kinds of furnaces, such as puddling, mill,
reheating, and the like furnaces to which it is more especially applicable, but may
also be usefully applied to other furnaces, such as air furnaces for foundry purposes
and the furnaces of boilers.
Our invention comprises various improvements and novel features as hereinafter
described which improvements provide a simple and effective way of bringing the
elements of combustion into combination by which their powers of generating heat
are developed and disposed of to the best advantage, and a saving of fuel is effected
or inferior fuel can be used, and less smoke is emitted from the chimney or uptake.
Also in puddling and the like furnaces we transfer the region of combustion from
the front end of the furnace above the furnace grate, which is its position in
puddling and the like furnaces as ordinarily constructed towards the other end of
the furnace above the hearth by which the heat developed in the furnace is more
directly applied to the process in haud and is diverted in a corresponding degree
from impinging upon and destroying the roof thereof. We also improve such
furnaces in several details of construction.
Various modifications in the form and construction of our improved furnace may
be made without departing from our invention which we will now describe by
referring to the accompanying drawings in which are illustrated convenient forms
and constructions of furnaces for effecting the purposes of our invention.
In the drawings in which like letters of reference indicate corresponding parts in
all the figures, Figure 1 is a longitudinal sectional view of our improved puddling
furnace taken on line of Figure 2 which is a corresponding sectional plan view
taken on line y y of Figure 1. Figure 3 is a transverse sectional view taken on

page_text: line of Figures 1 and 2, and Figure 4 is the front end view of the furnce.
showing the position of the steam jets for drawing air into the gas producer.
Figures 5 and 6 are sectional views of the furnace corresponding to Figures 1-
and 3 but showing a continuous slot shaped opening between the gas producer and
the combustion chamber in the place of the upper. row of chequer holes as.
illustrated in Figures 1 and 3 and which modification is thought a more suitable
construction of the furnace when used as a reheating furnace. Figure 7 is a
longitudinal section of the furnace as adapted to be used with an egg-ended boiler.
As our improvements are of great value when adapted to puddling furnaces we will
in describing how our invention is carried into effect refer in the first place to its
application to a puddling furnace as illustrated in Figures 1 to 4 inclusive.
Puddling furnaces as ordinarily constructed consist of a grate and a hearth
separated by a furnace bridge which leaves an unobstructed communication from
end to end of the upper part of the furnace. The fuel is placed on the grate
through which air is drawn to support combustion in the manner of an open fire.
What may be termed the region of combustion occupies the space above the fire
from which the products of combustion are drawn under a low arch or roof to the
flue at the stack end of the furnace; consequently the combustion is most intense
where it serves no useful purpose and is correspondingly diminished when it.
approaches the hearth of the puddling chamber, added to which the wasted heat
impinges upon and applies itself to the destruction of the furnace roof.
In a puddling furnace constructed according to our invention we divide the
furnace into two chambers a and b separated by the diaphragm wall c of which a is
the gas producing and the puddling chamber. The puddling hearth is bounded
or enclosed at one end by the usual furnace bridge d with cooling box e, and the
grate of the gas producer is also bounded or enclosed at one end by the gas producer.
bridge these two bridges d and f extend transversely across the furnace in the
usual way in parallel lines to the diaphragm wall c which comes between them in
the manner shown in Figures 1 and 2. The space between the diaphragm wall c
and the gas producer bridge f is occupied by the grating g whilst a relatively
narrow space between the diaphragm wall c and the furnace bridge d is the air
space or passage leading to the combustion chamber b; c¹ are openings in the form
of chequer work leading from the space above the grating g to the air space h
and are similar openings through the diaphragm wall through which the gas
producing chamber a delivers its gaseous products into the combustion chamber b.
The cooling box e is open to the outside air at the end e¹ only and instead of passing
straight out through the other side wall as is usual in puddling furnaces is brought
round in a curve and leads into the air space h at e²; 3 is a corresponding opening
through the side wall at the opposite part of the air space for admitting the outside
air direct into the said air space and is controlled as to its area by any suitable
means: ii are steam jets which enter the gas producer at j and draw in air beneath
the grating k. is a water trough placed below the small grating g.
In a puddling furnace constructed as above described the gas producing chamber a
is charged with fuel upon the grate k below which, that is, through the intakes j
air is admitted in just sufficient quantity to support a slow combustion of the fuel,
the gaseous products of which pass off at a low temperature through the openings c²
in the diaphragm wall c into the puddling chamber where they encounter the air
drawn in through the air space h. The bulk of the air which mixes with the
gaseous products in this way is drawn in below the grating 9 where a bright clear
fire preferably of coke breeze or cinder is kept burning, through which the air is
drawn and raised in temperature, the air then passes through the chequer holes c¹
and is further raised in temperature by absorbing heat from the surface of the
furnace bridge d, the air is thus raised to a considerable temperature before
reaching the combustion chamber and consequently on mixing with the gaseous
products above sets up and maintains an intense combustion. The air which passes
into the air space h from the cooling box e is also raised in temperature, absorbed
from the cooling box added to which this mode of utilizing the air so heated in the

page_text: cooling box creates a sharper draught through it and tends in consequence to render
the cooling box more effective in preserving the furnace bridge. The outside air
which is admitted through the opening is intended to be used as a means of
regulating the temperature of the furnace. Taking a puddling furnace with a
hearth of the usual dimensions, an air space three inches wide, with the walls
preferably converging slightly upwards is found to give good results in combination
with a grating g one foot wide.
It will be observed that the part of the furnace shut off as a gas producing
chamber a, instead of including the region of the most intense combustion, in our
improved furnace remains at all times comparatively cool, added to which it is
thought that the currents of heated air which pass up from the air space h to mix
with the gaseous products of the fuel attain sufficient force and velocity to penetrate
above these gaseous products which are in consequence forced downwards away
from the roof and onto the hearth of the puddling chamber.
Having thus described in detail the leading features of our invention we would
have it understood that while the same is more particularly intended for the
puddling process we do not confine ourselves to this use exclusively and we may
modify the furnace to adapt it to be used for other purposes as for instance when
applying our improvements to a reheating furnace we prefer to construct the furnace
as illustrated in Figures 5 and 6 in which instead of providing chequer holes for the
passage of the gaseous products from the producer a, the diaphragm wall c stops
short of the roof as shown leaving a long slot shaped opening through which the
gaseous products are delivered into the chamber at a higher level and with less
obstruction.
Figure 7 is a further modification of our invention adapting it to be used as a boiler
furnace in which the diaphragm wall extends over the air space flush with the
furnace bridge d through which the passages for the elements of combustion
converge towards each other in such a manner that the region of combustion is
elevated towards the boiler shell instead of being depressed downwards in the
manner required in the puddling furnace.
Having now particularly described and ascertained the nature of our said inven-
tion and in what manner the same is to be performed we declare that what we
claim is :-
:
Firstly In furnaces of the class hereinbefore referred to, the construction and
arrangement by which the furnace is divided into a gas producing chamber and a
combustion chamber, into which a supply of heated air is admitted, so that the
combination of the elements of combustion, and the disposal of the heat generated
is effected, substantially in the manner and for the several purposes as hereinbefore
described with reference to the accompanying drawings.
Secondly The particular construction of a puddling furnace as hereinbefore
described with reference to Figures 1 to 4 inclusive of the accompanying drawings.
Thirdly: The particular construction of the furnace as separately described with
reference to Figures 5 and 6, and as separately described with reference to
Figure 7 of the accompanying drawings.
Dated
13 BALL
Schober
.
1001
5333 L
STRO KAMAYTAY On nu-2-2
G. J. CLARKSON,
Stockton-on-Tees, Agent for the Applicants.