Improved Apparatus for the Prevention of Smoke in Boiler and other Furnaces.
Year: 1890

page_text: Improved Apparatus for the Prevention of Smoke in Boiler and
other Furnaces.
I, WILLIAM DENHAM GRIMSHAW of Plantation Street Works, Accrington, Lancashire,
Calico Printer do bereby 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 :-
This invention relates to improved apparatus for increasing the combustion of fuel
and preventing the formation of smoke in steain boiler and other furnaces, whether
fired by hand or by mechanical means. My present improvements consist in placing
within the furnace at a suitable position between the level of the fire bars and the
crown of the flue or furnace, two longitudinal pipes extending from the front of the
furnace to the bridge, or the said pipes may extend a suitable distance beyond the said
bridge. These longitudinal pipes are perforated, the first of which perforations may
commence at a distance from the front of the furnace of about the width of the dead
plate, such perforations extending from this point to the opposite end of the said pipes.
The perforations in one of the pipes are bored diagonally so that when a jet of steam
or air enters into the end or orifice of the pipes, such diagonally bored holes will cause
the current of air and steam to descend in a diagonal line to the opposite side of the
furnace, causing the flames arising from the fuel to be swept or forced like a wave to
the other side of the furnace, but the up-current of air passing up through the grate
bars will cause the flame to ascend, when the current of air or steam being forced out
of the perforations in the other longitudinal pipe impinges against the rising flames,
throwing the said flames back to the other side of the furnace; such flame taking the
shape of a wave or crescent, the upper part of which impinges against the underside
of the flue of the furnace, and this takes place almost from the dead plate to the bridge
of the furnace, consequently the flames arising from the fuel are utilized almost
throughout the whole length of the furnace, which is not the case with the present
construction of furnace, as the draught therein draws the flame with great rapidity
from the front to the furnace right to the bridge, consequently a considerable portion
of the furnace flue is not impinged against by the flames, thus the flames of the furnace
are only partially utilized.
In order that my invention may be better understood I will now make reference to
the accompanying sheet of drawings illustrative thereof, wherein Fig. 1 is front
elevation of a double flued steam boiler having my improvements applied thereto, and
Fig. 2 is cross section of the same. A and B are the flues of the boiler, provided with
grate bars Cin the ordinary manner. Within each flue of the furnace are placed two
longitudinal pipes D and D¹, the front ends of which are open and project beyond the
front of the boiler but the opposite ends of said pipes are closed, and they project into
the furnace as far as the bridge, or beyond if necessary, according to the particular
class of fuel being used. These pipes D are supported at their front ends by brackets a,
and they are also supported within the furnace flue by other brackets b. I prefer
that the positions these pipes occupy in the furnace shall be as follows, viz.: if the
flue be three feet in diameter, I prefer that the said pipes D shall be about 12 inches
above the dead plate and in close proximity to the inner surface of the flue, as
shewn in the accompanying drawings, about the same proportions being followed
with varying sizes of flues. So long as the smoke preventing appliance is in use
a jet of steam is made to enter the orifice of each pipe, being conveyed thereto by
the small pipes c as shewn in Fig. 1 of the accompanying drawings, such pipe c being
provided with valves or taps d for the purpose of shutting off and supplying the
steam as and when required. Instead, however, of forcing steam through the
longitudinal pipes, jets of air may be blown through, generated by a fan placed in

page_text: any suitable position. For the purpose of causing or directing the jets of steam or air
in a suitable direction across the furnace, the said holes must be drilled at an angle
so that the current of air or steam is thrown across the furnace as shewn at e in
diagram Fig. 3, where the flames of the furnace are forced; but when the current
of air or steam has spent itself, the up-current of air passing through the grate bars
will cause the flames to ascend as shewn at fin Fig. 3, and as such flames ascend,
they are caught by a current of air or steam being forced through perforations
drilled at about right angles with the other pipe D¹, whereby such, flames are forced
back across the furnace, so as to impinge the crown of the flue, thereby utilizing from
about the dead plate to the bridge the whole width or volume of flame, which is not
the case when the draught of the chimney draws the whole of the flame straight
away to the bridge.
In Fig. 4 I have shewn the perforations in the pipes D to be drilled so as to force
the flame diagonally across the furnace, and in Fig. 5, I have shewn what would be
the effect of the flames if the holes were drilled at a less angle than the e already
described; and whilst all the three methods are much more effective than the present
method of allowing the flames to pass at once to the bridge, yet I prefer the method
shewn in Fig. 3.
The forced current or currents of air (either mixed with steam or otherwise) in
a finely divided state mingles freely with the products of combustion as soon as
they are evolved from the full and will cause complete combustion thereof before
they arrive at the bridge of the furnace, and this takes place without in any way
reducing the temperature or draught, and thus not only will the combustion of the
fuel be more complete and economical, but the effective heat will be increased and the
formation of smoke prevented.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed, I declare that what I
claim is :-
Firstly The improved apparatus for the prevention of smoke in furnaces,
consisting of perforated pipes D, extending as far as the bridge of the furnace or
beyond the said bridge, in combination with steam jets or with forced currents of air,
all constructed and applied substantially as herein described.
:-
Secondly The improved apparatus for the prevention of smoke in furnaces,
consisting of perforated pipes D extending as far as the bridge of the furnace or
beyond the said bridge, in combination with steam jets or with jets of air, caused
to pass and repass across the furnace in a diagonal direction in manner and for
purposes shewn and described in the accompanying drawings.
Dated this 6th day of January 1890.