Improvements in and relating to Furnaces for Steam Boilers.
Year: 1894

page_text: Date of Application, 22nd Mar., 1894
Complete Specification Left, 1st Sept., 1894-Accepted, 20th Oct., 1894
PROVISIONAL SPECIFICATION.
Improvements in and relating to Furnaces for Steam Boilers.
I, FEDERICO ALESSI, of Sestri-Ponente, in the Kingdom of Italy, Ship-Captain,
do hereby declare the nature of this invention to be as follows:-
My invention relates to furnaces for steam boilers and has for its object to
provide for the utilization of coal too small to be burnt upon the ordinary grates
of steam boiler furnaces, such as for instance coal dust and residues from the coal
which, by reason of their small size, drop from the ordinary grates, especially in the
necessarily frequent clearing of such grates, and which still consist partly or wholly
of combustible material.
This invention comprises an improved arrangement and simple parts which can
be easily and rapidly applied at a small cost not only to furnaces to be newly
built, but also to any existing furnace irrespective of its type and mode of
construction.
I will proceed to describe my improved furnace with special reference to its
application to a marine boiler, but it will be readily understood that this furnace is
also applicable to any other boiler.
In a furnace having an ordinary grate with fire-bars I provide a plate made of
refractory material and placed parallel to the aforesaid grate at a suitable height
above the same, so that the combustion of the coal may take place equally upon
the said grate. However the quantity of coal burnt upon the latter will be very
small as compared with the quantity necessary in the usual operation of the grate
alone. This plate, which is made of a suitable thickness, for instance 4 inches, and
whose general form in plan is rectangular with the two rear corners rounded off,
does not occupy the entire horizontal sectional area of the furnace, but leaves a
comparatively large passage at the rear part and two narrower passages at the two
sides. This has for its object in the first place to allow the arrival upon the said
plate of the air necessary for the combustion and coming from the ash-box when the
door of the furnace is closed to obtain a strong draft; in the second place to have
the said plate enveloped on all sides by the flames due to the combustion upon the
aforesaid grate; and in the third place to enable these flames to circulate also in
the ordinary manner along the sides and top of the furnace.
For supporting the plate of refractory material in the before-mentioned position
I provide it with a semi-circular groove extending along the two lateral edges and
the rear edge, and place in this groove a pipe of copper, brass or other metal
capable of withstanding the action of the flames. The said pipe is provided at
each of the two lateral edges of the plate with two or more rounded bends directed
outwards to such an extent that their extreme points will bear exactly against the
two lateral walls of the furnace. When the latter is cylindrical the rounded bends
of the pipe simply bear upon the walls and are held by reason of the contraction of
the horizontal section of the furnace, which section gradually diminishes from the
horizontal axial plane to the bottom of the furnace. When the furnace has a
section which does not diminish towards the bottom, as for example when it is
parallelipipedic or tapering upwards, the plate is held by small supporting walls,
columns or pillars of refractory material arranged longitudinally along the two
sides of the furnace.
The two ends of the said pipe pass to the outside of the furnace through holes
in its front, which corresponding in diameter to that of the pipes are provided at
the two sides of the furnace door. Each end of the pipe is furnished at a suitable
point with a cock or a stop valve. By means of two conduits suitably arranged,
one of the two ends is designed for the suction of water and the other for the

page_text: forcing of water into the boiler; which water, passing through the said pipe will
prevent it from being damaged by the flames and by the high temperature existing
in the furnace. In the case of a marine boiler the suction pipe is provided with a
branch pipe having a stop valve for enabling sea water to be drawn if required,
that is to say if soft water should be wanting in the reservoirs on deck. The force
pipe is also provided with a branch pipe, in order that, when too much water is
delivered for the feed of the boiler, it may be conducted either to cooling reservoirs
or other places.
The operation of the improved furnace is very simple.
I commence by placing coal, upon the grate and light it. By a pump or other
appropriate means I cause cold water to circulate in the pipe extending round the
edge of the aforesaid plate. As the water in the boiler begins to evaporate the
heat absorbed by the plate renders the latter incandescent. Then I charge it with
small coal, coal dust, residues or the like which will burn immediately. On the one
hand I regulate the admission of cold water into the said pipe and the delivery of
this hot water, for feeding the boiler with it, or for storing it in cooling reservoirs
or for any other use, and on the other hand the supply of pit coal to the grate, and
of small coal, coal dust and residues from the grate to the plate, the quantities used
being proportional to vaporization and to the pressure to be produced; and lastly
I regulate the draft of the air for the combustion by opening and closing the doors
of the furnace and ash box.
Under these circumstances and without requiring more attention on the part of
the stoker than the ordinary furnace having a simple grate with fire bars, my
improved furnace may be operated perfectly and with great facility.
It will be evident that this furnace, as compared with the furnaces heretofore
employed, possesses the following advantages:-It enables small coal, coal dust,
residues falling from ordinary grates and the like to be burnt in the most complete
manner. By heating the plate of refractory material to incandescence, which plate
if necessary restitutes by radiation the heat absorbed, it keeps the temperature of
the furnace more constant, and therefore also the evaporation and the tension in
the boiler, even with a less continuous supply of fuel. By reason of the incan-
descence of the said plate it renders the lighting of the newly introduced coal
easier and more prompt. It provides simple and prompt means for feeding the
boiler with hot water, thus obviating the various inconveniences of heaters,
condensers and the like, the arrangement and maintenance of which are moreover
very costly. A considerable saving of fuel is obtained, which is due to the low
price of small coal and to the otherwise impossible utilization of the residues
falling from the grate, and also to the much smaller quantity of fuel necessary for
obtaining the same amount and the same tension of steam. It consists of few parts,
which can be easily constructed and rapidly applied to any furnace, either to be
built or already built and belonging to any known type, so that the said furnaces
may optionally be employed either with the ordinary grate alone or with the grate
combined with the burner plate.
Dated his cond
L 1004
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.
COMPLETE SPECIFICATION.
Improvements in and relating to Furnaces for Steam Boilers.
I, FEDERICO ALESSI, of Sestri-Ponente, in the Kingdom of Italy, Ship
Captain, do hereby 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 :--
My invention relates to furnaces for steam boilers and has for its object to

page_text: provide for the utilization of coal too small to be burnt upon the ordinary grates
of steam boiler furnaces, such as for instance coal dust and residues from the coal
which, by reason of the small size thereof, drop from the ordinary grates, especially
in the necessarily frequent clearing of such grates, and which still consist partly or
wholly of combustible material.
This invention comprises an improved arrangement and simple parts which can
be easily and rapidly applied at a small cost not only to new furnaces, but also to
any existing furnace irrespective of its type and mode of construction.
In the accompanying drawing I have more especially represented the application
of my invention to a type of marine boiler, but it will be readily understood from
the description and drawings that it is also applicable to any other boiler.
Figure 1 is a longitudinal vertical section of the boiler.
Figure 2 is a transverse vertical section of the same through the furnace.
Figure 3 is a perspective view of the parts constituting substantially the present
invention.
Figure 4 is a transverse vertical section of a furnace (here supposed to be
parallelipipedic) with the present invention applied thereto.
In all the figures the same letters of reference designate the same parts.
In carrying my said invention into practice I place in a furnace F having
an ordinary grate G with fire-bars a plate P made of refractory material and
arranged parallel to the aforesaid grate at a suitable height above the same, so
that the combustion of the coal may take place equally upon the said grate.
However the quantity of coal burnt upon the latter will be very small as
compared with the quantity necessary in the usual operation of the grate alone.
This plate, P which is made of a suitable thickness, for instance 4 inches, and
whose general form in plan is rectangular with the two rear corners rounded off,
does not occupy the entire horizontal sectional area of the furnace, but leaves a
comparatively large passage g at the rear part and two narrower passages g¹ g² at
the two sides. This has for its object in the first place to allow the passage to the
said plate P of the air necessary for the combustion and coming from the ash-box
when the door of the furnace is closed to obtain a strong draft; in the second
place to have the said plate P enveloped on all sides by the flames due to the
combustion upon the aforesaid grate; and in the third place to enable these flames
to circulate also in the ordinary manner along the sides and top of the furnace.
For supporting the plate P of refractory material in the before-mentioned
position I provide it with a semicircular groove extending along the two lateral
edges and the rear edge, and place in this groove a pipe T, of copper, brass or
other metal capable of withstanding the action of the flames. The said pipe is
provided at each of the two lateral edges of the plate with two or more rounded
bends directed outwards to such an extent that their extreme points will bear
exactly against the two lateral walls of the furnace. When the latter is
cylindrical as in the boiler shown in Figure 2, the rounded bends t¹² of the pipe T
simply bear upon the walls f¹f and are held by reason of the contraction of the
borizontal section of the furnace which section gradually diminishes from the
horizontal axial plane to the bottom of the furnace. When the furnace has a
section which does not diminish towards the bottom, as for example when it is
parallelipipedic or tapering upwards, the plate P is held by small supporting walls,
columns or pillars of refractory material arranged longitudinally along the two
sides of the furnace.
The two ends of the said pipe T pass to the outside of the furnace through holes
in its front, which corresponding in diameter to that of the pipes are provided at
the two sides of the furnace door. Each end of the pipe is furnished at a suitable
point with a cock or a stop valve. By means of two conduits suitably arranged
one of the two ends is designed for the suction of water and the other for the
delivery of water into the boiler; which water, passing through the said pipe T
will prevent it from being damaged by the flames and by the high temperature
existing in the furnace. In the case of a marine boiler the suction pipe is provided

page_text: with a branch pipe having a stop valve for enabling sea water to be drawn in if
required that is to say if soft water should be wanting in the reservoirs on deck.
The force pipe is also provided with a branch pipe, in order that, when too much
water is delivered for the feed of the boiler, it may be conducted either to cooling
reservoirs or other places. The two pipes above mentioned and their branch
pipes are not shown in the drawing, for the sake of clearness, as the same are not
necessary for the exact and complete understanding of the invention.
The operation of the improved furnace arranged as described and shown in the
drawing is very simple. I commence by placing coal, upon the grate G and light
it. By a pump or other appropriate means I cause cold water to circulate in the
pipe T at the same time that the water in the boiler begins to evaporate the heat
absorbed by the plate P renders the latter incandescent. Then I charge it with
small coal, coal dust, residues or the like which will burn immediately. On the
one haud regulate the admission of cold water into the said pipe T and the
delivery of this hot water, for feeding the boiler with it, or for storing it in cooling
reservoirs or for any other use, aud on the other hand the supply of pit coal to the
grate G, and of small coal, coal dust and residues from the grate to the plate P,
the quantities used being proportional to vaporization and to the pressure to be
produced; and lastly I regulate the draft of the air for the combustion by opening
and closing the doors of the furnace and ash box.
Under these circumstances and without requiring more attention on the part of
the stoker than the ordinary furnace having a simple grate with fire bars my
improved furnace may be operated perfectly and with great facility.
It will be evident that this furnace, as compared with the furnaces heretofore
employed, possesses the following advantages:-It enables small coal, coal dust,
residues falling from ordinary grates and the like to be burnt in the most complete
manner. By heating the plate of refractory material to incandescence, which plate
if necessary restitutes by radiation the heat absorbed, it keeps the temperature of
the furnace more constant, and therefore also the evaporation and the tension in
the boiler, even with a less continuous supply of fuel. By reason of the incan-
descence of the said plate it renders the lighting of the newly introduced coal easier
and more prompt. It provides simple and prompt means for feeding the boiler
with hot water, thus obviating the various inconveniences of heaters, condensers
and the like the arrangement and maintenance of which are moreover very costly.
A considerable saving of fuel is obtained, which is due to the low price of small
coal and to the otherwise impossible utilization of the residues falling from the
grate, and also to the much smaller quantity of fuel necessary for obtaining the
same amount and the same tension of steam. It consists of few parts which can be
easily constructed and rapidly applied to any furnace, either new furnaces or
existing ones and of any known type, so that the said furnaces may optionally be
employed either with the ordinary grate alone or with the grate combined with the
burner plate.
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 :-
First. In furnaces for steam boilers the improved arrangement of a burner plate
of refractory material provided above the ordinary bar grate mounted upon and
carried by a water-circulating pipe with or without the support of small walls
columns or pillars, also constructed of refractory materials.
Second. In furnaces for steam boilers the combination of the ordinary bar grate
with the burner plate of refractory material as set forth in the first claim.
Third. In the improved arrangement of furnace for steam boilers as set forth in
the first claim the combination of the burner plate of refractory material with the
water-circulating support pipe of non-attackable metal and with or without small
walls columns or pillars for supporting the pipe, these walls being also made of
refractory materials.

page_text: Fourth. In the water-circulating support pipe as set forth in the first and third
claims the arrangement of rounded bends of the same pipe bearing either upon the
flanks of the wall of the furnace when the latter is cylindrical or upon small walls,
columns or pillars when the furnace is not contracted downwards.
Fifth. The improved furnace constructed and arranged substantially as herein-
before described and shown in the drawing and for the purpose specified.
Dated this 1st day of September 1894.
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.