IMPROVEMENTS IN FURNACES AND BOILERS, AND IN THE GENERATION AND TREATMENT OF STEAM
Year: 1858

page_text: LETTERS PATENT to David Auld, of Glasgow, in the County of Lanark,
North Britain, Engineer, for the Invention of
for the Invention of "IMPROVEMENTS IN
FURNACES AND BOILERS, AND IN THE GENERATION AND TREATMENT OF STEAM."
PROVISIONAL SPECIFICATION left by the said David Auld at the
Office of the Commissioners of Patents, with his Petition, on the 13th
November 1858.
I, DAVID AULD, of Glasgow, in the County of Lanark, North Britain,
Engineer, do hereby declare the nature of the said Invention for "IMPROVE
MENTS IN FURNACES AND BOILERS, AND IN THE GENERATION AND TREATMENT OF
STEAM," to be as follows, that is to say :-
This Invention relates, in the first place, to the so arranging the furnaces
or fire-places of steam boilers, as well as furnaces for other purposes, that
economy in the consumption of fuel is secured, along with the prevention of
the emission of smoke, and the obtainment of a superior amount of steam or
working effect.
In applying this portion of the Invention in practice where the furnace is
inside the boiler, a narrow vertical water space of metal is fitted along each
side of the furnace, running from back to front. This water space extends
upwards from the level of the grate bars, or from any desirable lower level to

page_text: the flue plate above, an air space being left between the exterior of the water
space or hollow diaphragm and the shell of the flue. At intervals throughout
the length of these water spaces, water connecting tubes form communications
between the upper parts of the water spaces and the main body of the boiler
through the flue shell, so that the steam formed in the side water spaces can
find a free exit from them to the upper part of the boiler, and thence to the
steam chamber or dome. In addition to this provision each water space is
fitted with a series of transverse stay tubes opening up thoroughfares between
the spaces inclosed by the water diaphragms and the main body of the furnace.
The atmospheric air necessary for the combustion of the fuel in the furnace is
supplied by an air thoroughfare regulated or governed by the tumbling sand
box valve, for which Mr. Auld has already obtained British Letters Patent,
bearing date on or about the 29th day of April 1858; or the air may be
governed as to its inlet by other means. The air so supplied is passed in
through a hollow or cellular bridge at the back or other part of the furnace,
provision being made for the discharge of the air from the bridge on each side
into the back portion of each space inclosed by the side water diaphragms.
The air thus flowing into these spaces then finds its way in divided streams
through the lateral tubes of the diaphragms or water spaces into the furnace
on each side, and thus the air is supplied to the burning fuel in a heated state
and in a properly subdivided condition, so as to embrace the whole of the
burning mass upon the furnace bars. In this way the wasteful emission of
smoke is prevented, and combustion is maintained in a most efficient manner.
Instead of having two side water spaces one hollow central one may be used,
the hollow in the centre of the water space being in communication with the
air inlet at the bridge or otherwise, and air tubes being fitted into the section
of the water space on each side, for the transit through of the air into each
division of the furnace. This central water space is obviously of a hollow
saddle form, or, in other words, it is a water space bent so as to form two
parallel divisions for water with an air space in the centre.
According to another modification of this general arrangement the air spaces
at the sides of the furnace or at the centre thereof, are formed by vertical walls
of fire-brick work, with openings therein for the passage through of the air.
This latter modification may be used whether the furnace is inside or
outside the boiler. In constructing new boilers according to this general
system, flue tubes may be passed laterally from any outside or other flue
through the boiler shell and flue plate for the passage through of air to the
furnace.
1
This Invention relates, in the second place, to a mode of increasing the

page_text: efficiency of steam by passing it on its way from the boilers to the working
cylinders of the engine or other apparatus, through an arrangement of pipes
disposed in the discharge flues of the boilers. The heating pipes are kept free
from carbonaceous or other deposit by any convenient mechanical worker or
scraper. In this way the steam is dried or superheated, and rendered more
serviceable than usual by what would otherwise be wasted heat.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said David Auld in the Great Seal Patent Office on the
12th May 1859.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, DAVID
AULD, of Glasgow, in the County of Lanark, North Britain, Engineer, send
greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Thirteenth day of November, in the year of our Lord
One thousand eight hundred and fifty-eight, in the twenty-second year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto nie, the
said David Auld, Her special license that I, the said David Auld, my
executors, administrators, and assigns, or such others as I, the said David
Auld, my executors, administrators, or 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
FURNACES AND BOILERS, AND IN THE GENERATION AND TREATMENT OF STEAM,"
upon the condition (amongst others) that I, the said David Auld, by an instru-
ment in writing under my hand and seal, 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 Patent.
NOW KNOW YE, that I, the said David Auld, do hereby declare the
nature of my said Invention, and in what manner the same is to be performed,
to be particularly described and ascertained in and by the following state-
ment, reference being had to the accompanying Drawings, and to the letters
and figures marked thereon, that is to say:-
My said Invention relates, in the first place, to the so arranging the furnaces

page_text: or fire-places of steam boilers, as well as furnaces for other purposes, that
economy in the consumption of fuel is secured along with the prevention of
the emission of smoke, and the obtainment of a superior amount of steam or
working effect. In applying this portion of the Invention in practice, where
the furnace is inside the boiler, a narrow vertical water space of metal is fitted
along each side of the furnace running from back to front. This water space
extends upwards from the level of the grate bars, or from any desirable lower
level to the flue plate above, an air space being left between the exterior of
the water space or hollow diaphragm and the shell of the flue. At intervals
throughout the length of these water spaces, water connecting tubes form
communications between the upper parts of the water spaces and the main
body of the boiler through the flue shell, so that the steam formed in the side
water spaces can find a free exit from them to the upper part of the boiler,
and thence to the steam chamber or dome. In addition to this provision
each water space is fitted with a series of transverse stay tubes, opening up
thoroughfares between the spaces inclosed by the water diaphragms and the
main body of the furnace. The atmospheric air necessary for the combustion
of fuel in the furnace is supplied by an air thoroughfare, regulated or
governed by the tumbling sand box valve, for which I have already obtained
British Letters Patent, bearing date on or about the Twenty-ninth day of
April One thousand eight hundred and fifty-eight, or the air may be governed
as to its inlet by other means. The air so supplied is passed in through a
hollow or cellular bridge at the back or other part of the furnace, provision
being made for the discharge of the air from the bridge on each side into the
back portion of each space inclosed by the side water diaphragms. The air
thus flowing into these spaces then finds its way in divided streams through
the lateral tubes of the diaphragms or water spaces into the furnace on each
side, and thus the air is supplied to the burning fuel in a heated state and
in a properly subdivided condition, so as to embrace the whole of the burning
mass upon the furnace bars. In this way the wasteful emission of smoke is
prevented and combustion is maintained in a most efficient manner. Instead
of having two side water spaces, one hollow central one may be used; the
hollow in the centre of the water space being in communication with the air
inlet at the bridge, or otherwise, and air tubes being fitted into the section of
the water space on cach side for the transit through of the air into each
division of the furnace. This central water space is obviously of a hollow
saddle form, or in other words it is a water space bent so as to form two
parallel divisions for water with an air space in the centre.
According to another modification of this general arrangement, the air

page_text: spaces at the sides of the furnace or at the centre thereof are formed by
vertical walls of fire-brick work, with openings therein for the passage through
of the air; this latter modification may be used whether the furnace is inside
or outside the boiler. In constructing new boilers according to this general
system, flue tubes may be passed laterally from any outside or other flue,
through the boiler shell and flue plate, for the passage through of air to the
furnace.
This Invention relates, in the second place, to a mode of increasing the
efficiency of steam by passing it on its way from the boilers to the working
cylinders of the engine or other apparatus through an arrangement of pipes
disposed in the discharge flues of the boilers. The heating pipes are kept free
from carbonaceous or other deposit by any convenient mechanical worker or
scraper. In this way the steam is dried or superheated, and rendered more
serviceable than usual by what would otherwise be waste heat.
And in order that my said Invention may be properly understood, I shall
now proceed to describe the several illustrative Figures on the explanatory
Sheet of Drawings' which I have hereunto appended for the purpose of show-
ing certain modifications under which my improvements may be judiciously
carried out in practice, that is to say:-
Figure 1, on Sheet 1 of the accompanying Drawings, is an end elevation,
partially in section, of one modification of my improvements in arranging the
furnaces or fire-places of steam boilers; Figure 2 is a longitudinal elevation
of the arrangement delineated in Figure 1; Figure 3 is an elevation or side
view of the self-acting valvular apparatus for regulating and controlling the
admission of air to the burning fuel. Figures 4, 5, 6, and 7 refer to other
arrangements of the furnaces and boilers, and which are herein-after described
in sequential detail.
In the accompanying Sheet of Drawings, Number 1, my improvements are
shown as applied to the ordinary Cornish boiler, but the improvements are
equally applicable to boilers of other forms of construction. The brickwork A,
in which the boiler B is set, is built in the usual manner; the cylindrical flue
C, which extends through the body of the boiler B, has fitted within it at the
front extremity the furnace D; the fire bars E are supported in the ordinary
manner upon the dead plate F at the front end of the furnace, and upon the
fire bridge G at the backward end; the furnace D is divided longitudinally
by two vertical water spaces H, which in this modification extends downwards
through the flue C to the upper surface of the fire bars E. These water
spaces extend from the front part of the furnace backwards to the bridge, so
as to leave a channel or air space between the water space and the internal

page_text: surface of the flue C. Access is obtained to these air channels through a
balanced door or valve I, which is hung upon its centres at the front extremity
of each air channel; the doors I are fitted one on each side of the furnace
door J, as shown in Figure 1, on Sheet 1 of my Drawings. The air thus
admitted through the valvular doors I flows through the lateral tubular open-
ings which are made in the water diaphragms H; these openings or air
passages K are, by preference, arranged in parallel rows, and serve to convey
the inflowing currents of air directly in contact with the burning fuel, and
with the smoke as it is evolved therefrom. The valvular doors I are fitted
in the door plate I, which is bolted to the front end of the boiler, and the
doors are hung upon laterally projecting studs, so as to swing to and fro with
great freedom. Above the furnace door is arranged the self-acting apparatus
for regulating the opening and closing of the doors I; this apparatus consists
of the horizontal shaft M, the journals of which are carried in brackets pro-
jecting from the end plate of the boiler; the shaft M has fast to it a tumbling
sand box N, the motion of which about its axis gradually closes the valvular
doors; the box N is of a rectangular figure, and, by preference, is made of
iron; it has within it, near the upper part, an angularly projecting shelf or par-
tition which forms a sort of pocket or holder to receive a quantity of sand
which is placed within the box. The lower part of the slanting shelf near
the back of the box is perforated to allow the sand to fall slowly down to the
bottom of the box.
A valvular box constructed upon a plan similar to this, is described in the
Specification and shown in the accompanying Drawings appertaining to British
Letters Patent granted to me, and bearing date on or about the Twenty-ninth
day of April, One thousand eight hundred and fifty-eight. I have, therefore,
thought it unnecessary to cause the internal arrangement of the box to
be delineated in the annexed Drawings. Each time that the furnace door is
opened for the purpose of supplying the fire with fuel, the sand box N is
turned over, so that the sand is thrown from the lower part of the box to the
upper part thereof, where it falls behind the projecting angular shelf; this
is effected by the mechanical arrangement connected with the sand box N;
the shaft M has keyed to it a pendant lever arm O, the free extremity of which
rests upon or is in close contiguity with a roller which is fitted on a stud
projecting laterally from the lower and free extremity of the bent lever P;
this lever is centred on a stud which is fixed in the bracket' Q. The backward
end of the lever P is curved upwards towards the front part of the boiler, and
it has attached to its extremity a chain R, which is carried downwards and under
a pulley on the fire-door plate L, and is made fast to the door J. On the shaft M

page_text: and parallel with the lever P, is keyed a pulley S, to the periphery of which
is fastened one extremity of the chain T, the other end of this chain being
fast to an eye on the lower part of the valvular door I. When the furnace
door is thrown back, the chain R is drawn downwards, by which means the
lever Qis inverted, as shown in dotted lines in Figure 3, on Sheet I. of my
Drawings; the sudden inversion of the lever P throws up the lever arm O,
thereby causing the shaft M to turn upon its axis and suddenly invert the sand
box N, so that the sand is thrown to the upper part of the box. When the fire
is supplied with fuel and the door J is closed, the chain R is released, and the
lever P is restored to its normal position by the counterweight on the
extremity of the vertical arm; in this position of the parts the box N is in the
angular or diagonal direction shown in Figure 3. and the doors I are in
equilibrio, or very nearly so, in order that the full current of air may be
admitted through the air channels and tubular passages K to the green
or fresh uncarbonized fuel, thus affording the largest amount of oxygen to
enter the furnace during the time that the carburetted hydrogen is being
evolved with great rapidity from the burning fuel. The effect of these
streams or currents of air passing through the tubular passages K is that the
combustible gases are fully and effectually ignited at the instant they are
evolved, so that the emission of visible smoke is prevented, and the consumption
of fuel economised. The valvular doors J are caused to close gradually as
the emission of the combustible gaseous matters censes, and the fuel attains a
bright red heat; this gradual closing of the valvular doors is effected by the
flowing of the sand contained within the box N through one or more apertures
made for the purpose in the lower part of the angular shelf. As the sand
falls to the bottom of the box, the gradually increasing weight causes it to
slowly assume a vertical position, as indicated by the dotted lines in Figure 3
on Sheet 1 of the accompanying Drawings. The rotation of the box N about
its axis carries with it the shaft M and pulley S, the rotation of which draws
up the chain T, so as to close the doors J in a ratio corresponding to the
movement of the sand box. The velocity with which the sand is allowed to
fall to the bottom of the box N is regulated by a screw or screws, by which
the aperture or apertures at the bottom of the angular shelf may be more or
less closed.
Another modification of my improvements is shown in Figure 4 on
Sheet of the accompanying Drawings. In this arrangement the air is
admitted through a central vertical channel which is formed between the
parallel walls of a single water space, that is to say, the water space H is
formed by continuing the boiler plate downwards from the crown of the

page_text: cylinder C as low as the fire bars E or below them, and then upwards again
to the crown; in this manner the water space forms a double wall, which
encloses a central air passage or channel I. The inflowing air passes from
the channel through the lateral passages K, to the furnaces D on either side
of the water space H. The admission of air to the channel I is controlled
by means of a valvular door similar to the doors I, shown in Figures 1 and 2,
on Sheet 1 of the accompanying Drawings, and the motion of the door about
its axis is regulated by an arrangement of a self-acting tumbling sand box
similar to that herein-before described. The action of this modification of
my improvements being in all respects similar to the arrangement shown in
Figures 1, 2, and 3. it is unnecessary to repeat these details. In Figures
5 and 6, on Sheet 1 of the accompanying Drawings, is shown an arrangement
for preventing the emission of visible smoke, in which arrangement the air
channels are external to the boiler and arranged in the flues of the brickwork.
Figure 5 is an end elevation partially in section, and Figure 6 a partially longi-
tudinal section of the modification, the parts corresponding to those shown
in Figures 1 and 2 being marked with corresponding letters of reference.
The air channels H are formed of fire-brick, and built in the space between
the brickwork A and the boiler B, and extending backwards as far as the
bridge G. The front open ends of these air channels H are closed by the
valvular doors I, the opening and closing of which are regulated by a self-
acting tumbling sand box corresponding to the arrangement hercin-before
described, and shown in Figures 1, 2, and 3, on the same Sheet of Drawings.
The air admitted to the channels H passes through the tubular passages K
into the furnace D, where it ignites the combustible gases as they pass off
from the burning fuel.
Another modification of these external air channels is shown in Figure 7
on my Drawings. In this arrangement the air channels H are formed outside
the central flue C, but within the boiler B. The air channels are rectangular
tubes formed of boiler plate arranged one on each side of the cylinder C, and
extending backwards parallel to the furnace D. As arranged in Figure 7, the
air channels H are divided by a transverse partition which separates the
channel into two parts or chambers, or one division only may be used if con-
venient, and the mouths or openings to the channels are closed by duplex
valvular doors, so that the upper chambers may, if required, be closed before
or in advance of the lower ones, or vice versa. The air admitted to the
chambers H passes into the furnace D through the lateral passages K, and by
so regulating the external valvular doors it may be caused to flow through
either chamber at pleasure.

page_text: The last modification referring to smoke-consuming apparatus in the present
Invention is shown in Figures 8 and 9, on Sheet 2 of the accompanying
Drawings, Figure 8 being an end elevation partially in section, and Figure 9
a corresponding longitudinal section of a portion of the boiler and furnace.
The air to be supplied to the upper part of the furnace passes along the air
channels H through the external valvular doors I; the air channels are formed
in the brickwork A, and are by preference formed in two compartments or
The air
chambers, as shown in Figure 8 on the accompanying Drawings.
escapes from the longitudinal channels H through the lateral apertures K
into the furnace D, as indicated by the arrows in Figures 8 and 9, on Sheet 2
of my Drawings. Each of the air channels H is closed by a valvular door I,
both doors being connected by a single chain T to the pulley S on the trans-
verse shaft M, a corresponding arrangement being fitted on each side of the
furnace door J. The arrangement and action of the regulating sand box N,
and its connected parts, are in all respects like those shown in Sheet 1 of my
Drawings and herein-before described, and therefore need not be recapitulated.
The length of the chains T may be so adjusted that either of the doors I may
These
be closed before the other, if such a course is found advantageous.
several improvements afford the means of retarding or facilitating the passage
of currents of air to the furnace with great case, so that the quantity admitted
thereto may be duly regulated in proportion to the gaseous matters evolved,
and thus effect the highest practicable economy in the consumption of the fuel
as well as preventing the injurious emission of smoke.
The last part of my present Invention refers to a mode of economising the
otherwise waste heat which ordinarily escapes into the shaft or chimney. An
arrangement for effecting this object is shown in Figures 10 and 11, on
Sheet 2 of the accompanying Drawings. Figure 10 is a longitudinal elevation
As here
partially in section, and Figure 11 is a plan of the arrangement.
arranged, the waste heat is applied to the heating of the steam on its way
from the boiler to the engine or to other apparatus, according to the purpose
to which it may be applied. The steam passes from the boiler a and dome b
along the parallel steam pipes c, which extend along above the flue d, in
which the superheating apparatus is arranged. From the under sides of the
pipes c there spring a number of elbow branches, to which are connected the
series of vertical pipes e. These pipes are carried down through the brick-
work of the flue d, and are united to a corresponding number of branches
projecting from the pipes f. The lower pipes are supported. on fire-clay
lumps placed on the floor or sole of the flue d, and the front ends of these

page_text: pipes are closed by blind flanges, and at the backward ends either cocks may
be fitted thereto to draw off the water of condensation, or if the position of
the flue does not admit of this arrangement, the pipes may be continued
upwards, and any water of condensation which may collect on the cooling of
the apparatus will be driven through by the steam. The steam pipes care
stopped at their mid-lengths by a solid diaphragm or partition in each, so
that the steam flows down the first series of vertical pipes e, along the pipe f
and up the second series of pipes, and so away to the engine or other appliance.
In this manner the series of pipes e absorb the heated gaseous matters evolved
from the burning fuel, and which would otherwise pass off unutilized. Το
prevent the pipes e from becoming coated with carbon or soot, which would
thus impair the conducting power of the pipes, an apparatus is fitted so as to
constantly move up and down their peripheries. A pair of pedestal bearings g
is arranged upon the brickwork of the flue d, and these bearings support the
horizontal shaft h, which derives its motion from the engine. The shaft h
has keyed to it the crank i, to the pin of which is attached the lower end of
the connecting rod j. The upper extremity of this rod is connected to the
beam k, which is carried upon the transverse shaft l, or in any other convenient
manner. The two extremities of the beam k have attached to them the rods
m, the lower ends of which are jointed to the cross heads n; these cross heads
each carry two rods o, which pass down through small holes made for the
purpose in the brickwork. The rods o are secured at their lower ends to two
iron frames p, which are made so as to closely encircle the pipes e, but not so
as to interfere with their reciprocatory movement. A slow and continuous
rotatory motion is imparted to the shaft h, so that the beam is caused to
alternately elevate and to depress the scrapers p. By this means the pipes are
at all times kept entirely clear from soot or oxide, and are thus maintained
in the best condition for receiving the heat of the outflowing gaseous
matters.
Having now described and particularly ascertained the nature of my said
Invention, and the manner in which the same is or may be used or carried
into effect, I may observe, in conclusion, that I do not confine or restrict
myself to the precise details or arrangements which I have had occasion to
describe or refer to, as many variations may be made therefrom without deviat-
ing from the principles or main features of my Invention; but what I consider
to be novel and original, and therefore claim as the Invention secured to me
by the herein-before in part recited Letters Patent, is,-
First, the genral arrangement and construction of furnaces and apparatus

page_text: for consuming the combustible gases evolved from coal and other fuel, and
preventing the emission of visible smoke, as herein-before described and shown
in the accompanying Drawings.
Second, the system or mode of arranging the longitudinal air channels or
passages in furnaces and boilers, the said channels or passages being formed
by the intervention of hollow diaphragms or water spaces, in which tubular
apertures are made for the admission of the air to the burning fuel, as herein-
before described and shown in the accompanying Drawings.
Third, the system or mode of arranging the air passage or channel in the
centre of the furnace, with a water space or perforated diaphragm on either
side, as herein-before described and shown in Figure 4 on Sheet 1 of the
accompanying Drawings.
Fourth, the system or mode of arranging the air channels or passages along
the flue, or external to the boiler, and of conveying the air therefrom through
tubular apertures to the furnace, as herein-before described and delineated in
Figures 5 and 6 on Sheet 1 of the accompanying Drawings.
Fifth, the system or mode of arranging the air channels or passages external
to the central flue or cylinder, but yet within the boiler, and of conveying the
air from these channels by means of lateral tubes, as shown in Figure 7 on
Sheet of my Drawings, and herein-before described.
Sixth, the system or mode of arranging the air channels in duplex chambers
or passages, the mouth or entrance to each of these passages being governed
by separate valvular doors, as hereinbefore described and delineated in
Figures 7, 8, and 9, of the accompanying Drawings.
Seventh, the system or mode of forming the air channels or passages and
the lateral apertures in the brickwork of the furnace, as herein-before
described and delineated in Figures 8 and 9 of the accompanying Drawings.
Eighth, the system or mode of gradually closing the valvular doors fitted at
the openings of the air channels or passages, by means of a self-acting move-
able or tumbling box or "tumbler," fitted contiguous to the doors, and arranged
so as to slowly close the valvular doors as the gases cease to be evolved, and
the admission of air above the fuel is no longer necessary, as herein-before
described and delineated in the accompanying Drawings.
Ninth, the general mechanical arrangement connected with the oscillatory
box or "tumbler," for the purpose of causing one or more valvular doors to
move or close in accordance with the regulating or controlling box or tumbler,
as herein-before described.
Tenth, the system or mode of utilising the otherwise waste heat of furnaces,

page_text: by applying it to superheat steam as the heat passes off through the flue, in
the manner and by means of the apparatus herein-before described and shown
in the accompanying Drawing, or any mere modification thereof.
Eleventh, the application and use of a mechanical arrangement or scraper
for clearing superheating steam pipes, as herein-before described.
In witness whereof, I, the said David Auld, have hereunto set my hand
and seal, this Tenth day of May, One thousand eight hundred and
fifty-nine.
DAVID AULD. (L.s.)