IMPROVEMENTS IN THE FURNACES OF STEAM BOILERS
Year: 1880

page_text: LETTERS PATENT to David Jones, of Birmingham, in the County of Warwick,
Civil Engineer, for an Invention of "IMPROVEMENTS IN THE FURNACES OF
STEAM BOILERS."
PROVISIONAL SPECIFICATION left by the said David Jones at the Office
of the Commissioners of Patents on the 4th May 1880.
DAVID JONES, of Birmingham, in the County of Warwick, Civil Engineer.
"IMPROVEMENTS IN THE FURNACES OF STEAM BOILERS."
This Invention relates to improvements in the furnaces of steam boilers.
According to my Invention I pass a blast of air through a hollow and perforated
bridge, so as to commingle in a heated state with the rich unconsumed gases in the
furnaces. The bridge is perforated from front to back diagonally upwards from the
fuel, and the blast is introduced at the underside of the bridge by a jet of
steam carried there through a pipe traversing the ash pit. The bridge is not
perforated on top. The jet of steam, and consequently also the blast of air, are
regulated to the consumption of fuel. I also use a steam pipe traversing the ash
pit and perforated on top, so that the steam issuing therefrom blows directly through
the bars, causing a strong upward draught of air. The ash pit may be partially
closed. The gases passing away from the furnace may be returned through a
section of the hollow bridge, or through a second bridge, and mix with a renewed
supply of heated air to enable their combustion to be completed before they finally
pass away.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said David Jones in the Great Seal Patent Office on the 4th November
1880.
DAVID JONES, of Birmingham, in the County of Warwick, Civil Engineer.
"IMPROVEMENTS IN THE FURNACES OF STEAM BOILERS."
This Invention relates to improvements in the furnaces of steam boilers.
And in order that my Invention may be clearly understood and readily carried
into effect, I will proceed to describe same with the aid of the accompanying
Drawings, reference-being-had to the letters and-figures-marked thereon, and-in--which-
Fig. 1 is a front elevation of a boiler with my improvements attached, and Fig. 2 a
longitudinal section of same; Fig. 3 is also a longitudinal section, but with part of
of my improvements slightly modified; Fig. 4 is a transverse vertical section of one
of the fire tubes showing the face of the perforated bridge.
.
According to my Invention I pass a blast of air and steam into and through a
hollow and perforated bridge A, so as to meet and commingle (as illustrated and
hereinafter described) in a heated state with the rich unconsumed gases in the
furnace. The bridge A has perforations a as shown from the front towards the
back, where they communicate with the hollow a! in the interior of the bridge.
These perforations a may be of any desired form and size, both longitudinally and
transversely, i.e., instead of being circular on cross section as shown they may be
square, oblong (as slots), or of any other suitable shape. I prefer however that they
should always narrow from the hollow towards the front of the bridge, so as to
increase the velocity of the draft passing through them. Also these perforations a
may be either horizontal as shown, or inclined either upwards or downwards from
the hollow a¹. The air to be forced through said perforations a is conveyed into
hollow a' by pipe B leading from the front of the boiler and open at the outer end.
Into the front end of this enters a steam pipe C in communication with the steam
space of the boiler, a cock being provided to introduce or shut off the steam as
required. On turning on the steam its exit from pipe B into bridge A causes a
rush of air into pipe B through its open end, whence it traverses the pipe and is
driven in a heated state out of the perforations a into the furnace, meeting full in
the front the heated products of combustion and unconsumed gases about passing
over the bridge, driving them back for a space of time whilst they are mixed with
a sufficient proportion of oxygen gas to effect their combustion and produce flame
instead of smoke, in which condition they pass on to the remaining heating surface
of the boiler. Thus not only is the smoke nuisance prevented, but great economy
of fuel is effected. The bridge A may be of fire brick, fire clay, iron, or any other
suitable material, and the number and size of the perforations a are regulated
according to the size of the fire grate and consumption of fuel. The height of the
perforations above the fire bars is regulated according to the depth of fuel used. I
also employ a steam blast for creating draft and supplying air and steam directly
underneath the fire bars. This is likewise effected by a pipe D traversing more or
less of the ash pit, and having the draft of air forced through it by steam pipe E.
Pipe D may terminate near the front of the ash pit, as seen at Fig. 2, or may be
carried further inwards, as seen at Fig. 3. In either case the end of the pipe D is
provided with a suitable distributor, designed to distribute the blast of air and
steam as desired. F is the shell of the boiler;, G, the fire tubes; and H, the furnace
bars.
It is evident from the foregoing that the combination of steam blast, hollow
bridge A, and front perforations a may be employed in various descriptions of
furnaces other than those of steam boilers.
Having thus fully described and ascertained the nature of this my said Invention,

page_text: and in what manner the same is to or may be performed, I would have it distinctly
understood that I do not confine myself to the precise details hereinbefore described
and illustrated in the accompanying Drawings, but what I claim as my Invention
to be secured by the hereinbefore in part recited Letters Patent is,―
1. The hollow bridge A having perforations a, substantially as hereinbefore set
forth and described and illustrated in the accompanying Drawings.
2. The combination of hollow bridge A, perforations a, and blast B, C,
substantially as hereinbefore set forth and described and illustrated in the
accompanying Drawings.
3. The combination of hollow bridge A, perforations a, and blast B, C, and D, E,
substantially as hereinbefore described and illustrated in the accompanying
Drawings.
In witness whereof, I, the said David Jones, have hereunto set my hand
and seal, this Fourth day of November, in the year of our Lord One
thousand eight hundred and eighty.
DAVID JONES. (L.S.)