IMPROVEMENTS IN BOILER-FURNACES
Year: 1881

page_text: LETTERS PATENT to Patrick Francis Dundon, of the City and County of
San Francisco, State of California, United States of America, Boiler Maker, .
for an Invention of "IMPROVEMENTS IN BOILER-FURNACES."
COMPLETE SPECIFICATION filed by the said Patrick Francis Dundon at
the Office of the Commissioners of Patents on the 21st July 1881.
PATRICK FRANCIS DUNDON, of the City and County of San Francisco, State of
California, United States of America, Boiler Maker. "IMPROVEMENTS IN BOILER
FURNACES."
My Invention relates to certain improvements in steam boilers and their
furnaces, and it consists, first, in a novel method of securing the frame or mud
ring which forms the floor or bottom of the water space between the walls
surrounding the fire box, known as the water-leg, whereby said floor may be
easily removed for the purpose of cleaning the water space, or repairing, or for
any other purpose necessary.
My Invention relates, secondly, to such an improvement in the construction of
the boiler furnace as to produce a more perfect combustion of the fuel, and more
especially that portion which usually escapes in the form of smoke and gas, all of
which will be more fully explained by reference to the accompanying 2 Sheets
of Drawings, in which Figure 1, Sheet 1, is a view showing the manner of securing
the mud ring or frame; Figure 2, the mud ring or frame detached; Figure 3,
a section through shell of boiler showing method of attachment, and Figures 4
and 5 cross sections through fire-box; Figure 6 (Sheet 2) being a transverse section
of a pair of boilers showing a front view of the bridge wall; Figure 7, a longitudinal
section of the furnace showing a transverse section of the bridge wall; Figure 8, a
transverse section of a boiler furnace showing steam jet tubes; Figure 9, a longi-
tudinal section of the same; Figure 10, a longitudinal section of a flue boiler
furnace showing the application of the bridge wall, and Figures 11 and 12 are
transverse sections of the mud ring.
The method of securing the frame or mud ring at present used is open to the
objection that it prevents a thorough cleaning of the water space, or making
repairs, because of the difficulty of removing the frame.

page_text: The water space between the walls needs to be cleaned out whenever there
is too great a deposit of sediment. This is done through hand holes near the
bottom of the water leg, but it is obvious that such a method is imperfect in its
results.
The manner in which the frame or mud ring is fastened in the water-leg, namely,
by rivets passing through both plates which form the walls and horizontally
through the mud ring, makes a solid connection, so that the mud ring cannot be
taken out to allow the water space to be cleaned, or to allow repairs unless the
rivets are cut or driven out.
The object of my Invention is to overcome this difficulty by fastening the mud-
ring or frame to the walls of the water leg in such a manner as to render it easy of
removal when necessary to gain access to the water space.
In the Drawings, A represents the shell of the boiler; B, B, are the walls of the
fire box inclosing the furnace, the interior of which is fitted in the manner usual
to this class of furnaces. Between the walls is the water space a; this space a is
closed at the bottom by the frame or mud ring D.
The manner of securing this mud ring to the bottom of the water leg is in this
case as follows:-
On its upper surface are formed the longitudinal grooves or channels b near the
edges, as shown. These channels are to receive the bottoms or edges of the walls,
and are deep enough to form a brace or support for the walls fitting within them
against the outward pressure.
In some cases the mud ring may be turned up or formed with a flange projecting
up outside the walls of the water leg, thus making a single groove or channel the
full width of the space between the walls of the leg, but the construction is
practically the same.
In the mud ring between the grooves b, or outside the walls of the water leg
are the holes c placed alternately on opposite sides, as shown. To the inner surfaces
of the walls B, B, and within the water space a, are riveted the straps E, having
their lower ends formed into screw bolts, so as to pass through the hole c in the
mud-ring. These straps are secured to the plates forming the walls of the water
leg in position corresponding to the holes e in the mud ring. When the mud ring
is fitted to the bottom of the walls the screw bolt ends of the straps pass through
the holes c and are secured underneath by nuts e, as shown. By screwing up the
nuts the mudring D and the walls B, B, will be drawn tightly together and form a
floor or bottom for the water space a. Any suitable form of packing, as lead,
cement, rubber, asbestos, or hemp may be used to make this joint water tight.
This manner of connecting presents a neat appearance, nothing being seen from
the outside but the heads of the rivets securing the straps to the plates of the
walls, and the nuts e underneath securing the ends of the straps and supporting
the mud ring D.
By unscrewing the nuts the mudring may be readily removed and replaced with
much facility. It will be seen that the method of securing the mud ring by means
of these vertical bolts may be. altered by making the ring enough broader than the
width of the walls to allow the bolts to pass through it on the outside of the walls
instead of between them. It may also be effected by forming a flange at the foot
of each of the walls through which and the mudring the bolts may pass, or a strip
of angle iron may be secured around the foot of the walls so as to fit upon the
mudring, which will be secured by passing.the bolts through the flange of this angle
iron, and securing them by nuts, as before described. But in most cases it will be
found that the method first described will be preferable.
Figures 6, 7, 8, 9, 10, 11, and 12 (Sheet II.), show the second portion of my
Invention, in which A is a boiler of any suitable construction to which it is desired
to apply my Invention. H is the furnace front; I is the furnace having the grate
bars J, upon which the fuel is received. Behind the grate-bars is the bridge wall
which is built up to form the outline of the bottom of the boiler or the crown of
the furnace, and at only a short distance from it.

page_text: The face of this wall is carried towards the furnace at the top so as to form a
projection or overhang K, which may preferably be in the form of a curve or
partial arch, and it tends to throw the flame and products of combustion towards
the front of the furnace before they are allowed to escape over the bridge wall.
At the front upper portion of the furnace is a pipe L, which extends across,
as shown, and has small perforations made in its lower rear portion so that steam
introduced into the pipe under pressure will be directed upon the incandescent
fuel and strike it obliquely and near the bridge wall. From this point it glances
against the bridge wall and follows the curve K, thus creating a current over the
top of the fuel and towards the front of the furnace. This current catches the
smoke, soot, and unconsumed gases which arise from the partially ignited fuel, and
prevents them from escaping at once over the bridge wall, but returns them
towards the front of the furnace, where they are caught by the steam jets and
thrown down upon the incandescent fuel, so that the combustion is rendered more
complete.
I form holes through the bridge wall in a line corresponding with the upper
surface of the wall. These holes are at such a point above the surface of the fuel
as to allow the flame from it to pass through, and this produces a heat which will
ignite the smoke and unconsumed gas which may have passed over the wall, so
that they will be consumed before they enter the flues or tubes of the boiler.
These holes may be horizontal or inclined, and are either formed in the wall or
of sections of pipe, which may be built in with suitable intervals between
them.
Steam is furnished to the pipe L from the steam drum or dome, or from any
desired point, and the steam may be superheated or not as is found most desirable:
I may also build the bridge wall hollow, as shown in Figures 6 and 10, and with
suitable openings at the bottom and at the top so as to admit a current of air which
will meet the gases passing over the bridge wall, and will thus furnish oxygen for
a more complete combustion of the same. The openings or passages M are made
through as before described. The openings for the admission of air to the hollow
wall may be made just below the grate bars, and they may be provided with valves
or dampers which are operated by rods leading out to the front of the furnace so
that the supply may be easily controlled.
It generally appears, and especially when coal is used as a fuel at the extreme
rear of the furnace and next to the bridge wall, and any addition of fuel made by
firing are usually near the front, so that the smoke and unconsumed gases produced
by the imperfect combustion of this freshly supplied fuel will arise near the front,
and the action of the air or steam blast as before described serve to retain them
within the furnace and to bring them into intimate contact with the hottest part
of the fuel by the action of the blast. It also causes a flaine from the fire to pass
through the holes in the wall and in a slightly upward direction on account of
the position of the openings, so that it will meet and consume any smoke, soot, or
inflamable gases which may have escaped over the bridge wall.
It will be seen
that to produce the best results the bridge wall should be carried up near to the
bottom of the boiler or to the crown sheet, according to the form of boiler used,
so as to equalize the draft at all parts of it. The form of the holes through it is
not material, but I have found that when in an inclined position they will be the
most effective.
When two or more boilers are set side by side, as in Figure 6, a wall o is built
between the two furnaces to prevent cross drafts when one set or the other of the
doors is opened, and the bridge wall is curved so as to follow closely the shapes of
the boilers, extending up between them as shown, and constructed in other respects
as before described. When tubular boilers are employed this bridge wall is so
placed as to leave a chamber or space behind it, and in front of the flues this
chamber serving as before described for a combustion chamber. The bridge wall
will be carried up to within a suitable distance of the crown sheet. When a short
furnace or a vertical boiler is employed a steampipe passes around it, and steam

page_text: may be admitted through inclined openings in the sides, as shown at P, Figures 8
and 9. The short pipes passing through these openings have caps with fine
perforations, through which the steam is thrown or sprayed into the furnace.
Having thus described my Invention, what I claim as new and desire to secure
by Letters Patent is,―
1. In a boiler furnace having the walls B, B, enclosing the water space a, the
frame or mud ring D with its grooves b, fitting the lower edges of the plates of
the walls, said mud rings being secured to the walls by the screw bolts E passing
down through the holes in the mud ring, and secured by nuts, substantially as
described.
2. In a boiler furnace the combination of the walls or shells A and B, having
between them the water space a, the grooved frame or mudring D, and the straps Ĕ
secured to the walls within the water-space a, and passing through the mudring
and secured by nuts underneath, whereby the said frame or mud ring D may be
easily removed when necessary, substantially as described.
3. The improvement in securing the mud ring or bottom plate to the walls of
fire box furnaces, consisting in perforating the ring or plate with vertical holes,
through which screw bolts Ẹ pass, having nuts by which the mud ring is secured,
said bolts being secured to the side of the water leg or passing through flanges
secured to said walls, substantially as described.
4. The bridge wall at the rear of a boiler furnace having its upper edge made
to correspond in form with the lower part of the boiler or the crown sheet, and
having the face towards the furnace forming an overhang or projection concaved
so as to direct the gases and smoke towards the front of the furnace, substantially
as hereindescribed.
5. The bridge wall of a boiler furnace having its upper surface approximating
in form and approaching to the bottom of the boiler, and with the curved projecting
flange or overhang, as shown, in combination with the steam or air blast jet
tube, which directs a blast so as to strike the fuel upon the grate at an angle
near the wall, whereby a return current is induced, substantially as hercin
described.
6. The bridge wall of a boiler furnace having its upper surface approaching and
conforming to the shape of the lower part of the boiler or crown, and having the
inclined holes or tubes extending through the wall above the fire level, so that jets
of flame may pass outward and upward from the incandescent fuel and meet and
ignite the smoke, soot, or gases which escape over the bridge wall in an unconsumed
state, substantially as herein described.
7. A boiler furnace having the air or steam blast jet tube extending across its
front upper portion so as to deliver a blast obliquely downward upon the fuel in
combination with the inwardly curving or projecting bridge wall having its upper
edge approaching and conforming to the lower part of the boiler, and provided
with the oblique holes or perforations, substantially as herein described.
8. In a steam boiler the furnace A having perforations or openings P in the
walls as shown, in combination with the surrounding steam pipe having the short
pipes leading through the openings, and having their ends adapted to spray the
steam into the furnace, substantially as herein described.
In witness whereof, I, the said Patrick Francis Dundon, have hereunto
set my hand and seal, this Thirtieth day of June, in the year of our Lord
One thousand eight hundred and eighty oue.