Improvements in the Construction of Fire Boxes for Water Tube. Boilers.
Year: 1898

page_text: Date of Application, 17th Oct., 1898-Accepted, 17th Dec., 1,898
COMPLETE SPECIFICATION.
Improvements in the Construction of Fire Boxes for Water Tube.
Boilers.
I, ALFRED FRANK HACK, of Greville Street, Prahran, in the Colony of Victoria,
Furnace Builder, do hereby declare the nature of this invention, and in what
manner the same is to be performed, to be particularly described and ascer-
tained in and by the following statement:-
The object of this invention is to provide improved means of promoting the
combustion of fuel in fire boxes, particularly those of water tube boilers of
the Babcock and Wilcox type, though the invention is applicable also to other
steam generators. The invention consists in the arrangement and details of
construction within such fire boxes of certain arches, bridges and flues as here-
after explained. The effect of this special construction is to divide the fire box
into certain chambers and to advantageously divide concentrate and direct the
flames.
The fire box is divided into two distinct but similar chambers immediately
above the fire grate by arches the arches being so located that the arch backs
or surfaces leave a narrow but clear space or chamber just underneath the
lowest tubes of the water tube boiler. This space I speak of as a third cham-
ber. The arches extend rearwardly and parallel to the tubes (in side elevation)
to a bridge or wall at the inner end of the fire grate. The flames after entering
the third chamber will dip on the other side of the said bridge into what may
be termed a fourth and enlarged chamber or area of combustion. The bridges
have large transverse openings entirely through their front and back ends for
the passage of heat, flame and gases, and there are flues (fitted with dampers)
leading from the outside of the fire box into the lower chamber in such position
as to deliver air therein over the fuel.
These flues are of special utility in combination with the other parts of the
construction..
Referring now to the accompanying drawings] which illustrate this inven-
tion as applied to a water tube boiler of the Babcock and Wilcox type, Figure 1
is a vertical transverse section; Figure 2 is a side sectional elevation; and
Figure 3 is a plan view from beneath the tubes of the boiler.
In these figures the same letters of reference denote like parts.
A shows the lowest row of water tubes of the boiler and A the tubes above
said row and B B the fire grate. Between these tubes and the grate there is
usually no division.
But by my invention divisions are made by means of arches C and D spring-
ing from side supports and central wall E, or one arch with its crown at the
top of said wall E. The backs C₁ D) of the arches are close to the lower
tubes A. The best distance to adopt depends upon the dimensions of the water
tube boiler and its fire box but where the transverse width from side to side
of the tube is 8 feet, and the tubes are comparatively close to the grate as in
the drawing the distance in question may be about 5 inches. With such a

page_text: distance the flames and heat passing through the arches
directed as to effectively heat the tubes A and A³, and also
course indicated by one of the arrows marked 5 in Figure
the aforesaid "third" chamber marked O into the aforesa
ber marked P over the bridge H which is intermediate bet
of the furnace, and the rear end I the said bridge ext
completely across the furnace.
om below are so
partly to take a
.e. dipping from
fourth" cham-
a the front end
ing transversely
By means of the arches there are produced two chamber 3 and G imme-
diately over the fire grate each of course supplied with a doc. for the admission
of fuel &c. and the wall E serves to prevent cold draugt entering one of
these chambers when the door of the other is opened. J, Ja e pairs of rearward
apertures and K K pairs of forward transversely extending apertures through
the arches C, D. The divisions L between these apertures may if desired be
omitted. M are flues from the atmosphere into the fire box to a plurality of
points N within the fire boxes close beneath the arches C and D that is to say
well above the fuel which will rest upon the fire bars B. There is shown one
inlet N into each side of each chamber F G from the flues M but in practice
I shall usually provide a plurality of inlets so as to deliver air not only under
the middle of the said arches but also at a short distance from the edge of
the apertures J as well as at a short distance from the edge of the apertures K.
Each flue M is controlled by a 'damper (not shown). The apertures N by
delivering air as described at points where the heat will be intense supply an
important gaseous fuel, and help to produce also a powerful draught of flame
and gases upward through the respective apertures J, J, K K.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is:-
1. In the fire box of a water tube boiler, an arch or arches as C and D hav-
ing transverse fore and rear apertures J and K a dividing wall E and a bridge H
all so combined as to form chambers and G immediately over the fire bars,
a chamber O between chambers F and G and the lowermost water tubes, and
a chamber P substantially as set forth.
2. In the fire box of a water tube boiler or the like the combination, with
an arch or arches as C and D located under the water tube A, of a dividing
wall E forming chambers F and G, a bridge H, flues M provided with dampers,
and outlets N from the said flues into the fire box one or more at each side of
each said chamber and G at a point above the height which will be attained
by the fuel upon the fire grate all substantially as described.
Dated this 17th day of October 1898.
WHEATLEY & MACKENZIE,
40, Chancery Lane, London, W.C., Agents.