Improvements in Bagasse Furnaces.
Year: 1889

page_text: Date of Application, 6th Aug., 1889-Accepted, 28th Sept., 1889
COMPLETE SPECIFICATION.
[Communicated from abroad by THE BABCOCK AND WILCOX COMPANY, of New
York City, in the United States of America, Steam Boiler Manufacturers.]
Improvements in Bagasse Furnaces.
I, WALLACE FAIRWEATHER, C.E. of 62 Saint Vincent Street, in the City of
Glasgow, Registered Patent Agent and Fellow of the Institute of Patent Agents
do hereby declare the nature of this invention and in what manner the same is to be
performed as communicated to me to be particularly described and ascertained in and
by the following statement :-
The object of my invention is to produce an improved apparatus for burning
bagasse without previous drying.
In combination with a bagasse furnace, I uso, directly under the boiler, auxiliary
furnaces to be fired with wood or other dry fuel, by hand, said furnaces being con-
structed somewhat like the bagasse furnace with side tuyeres and passages to admit a
forced cold or heated air blast; or to work with natural draft, through a draft door;
and these furnaces may be used independently of the bagasse furnace, when that
furnace is not working or at the same time.
The blast both for the bagasse furnace and the auxiliary furnaces is heated by the
waste heat from the boilers passing among the pipes of a heater situated in the course
of the waste heat from the boilers on its passage to the chimney.
It is the purpose of my invention to provide means whereby steam may be generated
quickly and at any time without depending upon the slower process of firing the
green bagasse, the combustion of the latter being dependent, in part at least, upon a
hot forced draft. To this end the invention consists in a central bagasse-burner having
as described a boiler furnace upon each side thereof, the bagasse-burner communi-
cating with said furnaces by lateral openings and being provided with dampers
whereby one or both of said boiler furnaces may be shut off from the bagasse burner,
these boiler furnaces being without grate bars and so arranged that when combustion
is fully established in the bagasse burner no fuel need be supplied to them.
The invention also embraces the arranging of a bagasse furnace, steam boilers. an
air heater, an air forcer and a chimney together with regulating dampers so that the
wasto heat on its passage to the chimney may pass from the boilers to and around the
pipes of an air blast heater. The blast after being so heated is forced at a high tem-
perature to the bagasse furnace; the arrangement of dampers also being such that
the waste heat can be shut off from the air heater and pass directly to the chimney so
It is also
that either a cold or a hot blast can be had at will for the bagasse furnace.
my object to produce an improved heater for heating the air by the waste gases of
combustion of such construction that all bends or turns are avoided and great heating
surface obtained.
I attain these objects by arrangements and mechanism shown on the drawings in
which
On Sheet 1, Figure 1 is a horizontal section.
Figure 2 is a vertical cross section through line A. B. of Figure 1.
Figure 3 is a longitudinal section through line C. D. of Figure 1.
Figure 4 is a longitudinal section through line E. F. of Figure 1.
Figure 5 is a rear view in section of heater and flue.
Figure 6 is a cross section through furnaces showing application to larger boilers
than shown at Figure 2.
Figure 7 is a part horizontal section through furnaces of Figure 5.
On Sheet 2 Figure 1 is a horizontal section.
Figure 2 is partly a vertical section through line E F and partly an outside view of

page_text: Figure 3 is a vertical section through line A. B., Figure 1.
Figure 4 is a section through line C. D.
Figure 5 is a rear view partly in section of the air heater and rear of boilers.
Referring to the modification of my invention represented on sheet 1 of the drawings
at G is a central bagasse furnace with contracted base and tuyeres for forced air blast
in its side walls. At H is the cleaning-out door. I, I, are air passages connecting to
hot or cold blast pipes J and at Figure 7 to similar pipes J. The blast pipes J
Figure 1, and J Figure 7 are provided with blast gates to turn on, shut off, or regulate
the blast to bagasse furnace G. At Lis the heater for heating the air by means of the
waste heat. M is an air forcer which forces cold air into the heater pipes L, which
air (after being heated by the waste heat passing around and among the heater pipes L)
passes at N to the air passages I, and to furnace G, through tuyeres O. The damp
bagasse enters through an opening P, which is provided with a suitable feeder. The
products of combustion pass out at openings Q under the boilers R, thence after
passing in the usual way among the boiler tubes the wasto heat passes to the air
heater through dampered openings S thence out from heater through dampered
openings T to flue U and to chimney V. Dampers at S can be shut and dampers W
opened when the waste heat escapes direct to flue U and the blast becomes a cold
blast. At X are auxiliary furnaces for wood or other dry fuel. They have side
tuyeres Y in the furnace walls and a plain hearth. The tuyeres Y connect to air
passages Z, thence to air heater at a where blast gates are provided to shut off turn
on or regulate the blast. If it is wished to use the furnaces X independently of the
bagasse furnace G the dampers & can be shut down and the furnaces X be fired under
the boilers by hand with wood or other dry fuel, and either natural draft be used
through doors c or cold or hot blast as may be desired.
The
The heater L is composed of straight pipes connected to two air boxes d and e.
air is forced in at f and passing through the heater pipes L passes out at air box e
wherever it may be required at either furnaces X or G. At g is a division wall
separating the two heaters L and at h are deflecting plates dividing about half the
heaters to compel the heat to a good distribution around the heater pipes in passing
through the heater. It has been found that the heat from a separate bagasse
furnace passing over the grate bars under the boilers in course of a short time
injures the grates from being constantly exposed to a high temperature of about
1500 to 1800 degrees and if any air is admitted under them in the ash pit while
the bagasse furnace is in operation the temperature under the boiler falls so that
it injures the production of steam. By omitting grate bars 1 avoid the speedy
destruction of such parts which is invariably produced by the groat heat generated
by the bagasse.
I believe it to be a new and useful improvement in an apparatus to burn damp
hagasse to provide auxiliary furnaces for the combustion of wood or other dry
fuel directly under the boilers.
In the modification. of my invention represented at sheet 2 of the drawings the
furnace of which is provided with a feed hole 1 into which the damp bagasse is fed
has an arched top 3 inside and a contracted base 4 square with the axis of the arched
top. On each side of the contracted base are tuyeres for air blast connecting to air
passages which air passages are connected together by other air passages over
the cleaning doors 5 of the furnace and the blast pipes 6 connect the united passages
with the air boxes of the air heater. At 12 are the flues for exit of heat from
furnace right and left to each half of the boiler series. The blower 7 forces cold air
into the central air box 8, which has a head into which the tubes 9, connect at one
end while the other ends of the same tubes 9 connect to heads on the ends of air
boxes 10, both air boxes and tubes being practically air tight. These end air boxes
connect to the blast pipes 6. At 11 are division plates through which the tubes 9 pass
and these plates cause the waste heat from boiler to pass inore thoroughly among
the tubes and deflect the current. The boilers 13 shown are water tube boilers and
the series is divided into two parts of substantially similar dimensions each located
in a boiler chamber upon each side of the bagasse burner. 14 is the bridge wall

page_text: and 15, 15, the drums. The heat from the bagasse furnace 2 enters under the inclined
tubes at the openings 12 and after passing transversely among the tubes in the usual
way with the character of boilers, the waste heat passes out at openings 16 to the
air heater thence it passes through openings 17 to the chimney 18. When steam is
being raised the dampers at the openings 16 are closed and dampers at the openings 19
are raised, the heat then passes direct to chimney 18 and not through the heater and
thus the danger of over-heating the heater tubes when no air is passing through is
avoided. Steam may be raised with ordinary wood either thrown in through the
furnace doors under the boilers or into the bagasse furnace. The boilers may be
provided with auxiliary furnaces with grates for firing with any fuel from the
front but where wood is cheap I prefer leaving the grates out on account of
danger of destruction from the bagasse furnace heat passing over them after steam
has been raised and the mill started.
The chimney is raised from the ground the base being elevated as shown on the
drawings and the hearth of the heater extends under it, a smoke chamber is thus
formed whose top is also covered around the base plate 21.
In the consumption of green bagasse for the generation of steam my experiments
have demonstrated that the degree of heat generated by the bagasse burner varies,
inversely, in proportion to the distance from the burner of the boiler tubos. Thus,
while I am able to obtain, under ordinary circumstances, a temperature of 2000° Fah.
at the points where the products of combustion emerge from the openings 12, this
temperature decreases within a certain distance from said openings to 1200° and at a
further distance to 400° Fah. or thereabouts; the above figures being approximate
only.
It is well known that in many sugar producing countries coal is a costly fuel and
difficult to obtain while wood is usually extremely scarce. For this reason the
bagasse is necessarily the most economical fuel. By the arrangement shown and
described I have found that the heat actually used in the generation of steam is
greatly economised as compared with the methods formerly in use. My experiments
have also demonstrated that the bagasse burner to work successfully should have a
large capacity as it requires a certain mass of fuel to secure the high temperature
necessary to the combustion of the wet bagasse. But a large battery of boilers
sufficient to absorb the heat from such a bagasse burner when placed at one side of the
burner as has heretofore been done, meets with the difficulty that those parts furthest
from the furnace get much less heat than those immediately adjacent, and there is
thus a serious loss of effect.
By my invention both these necessary conditions are made possible, namely, a
burner large enough to burn the bagasse to advantage and sufficient boiler capacity
to absorb the heat therefrom without that loss which was a necessary result of the
previous arrangement. There are also important advantages in a reduction of the
cost of construction due to making one bagasse burner answer for a greater number
of boilers and in obtaining an increased efficiency of the heating surface of said
boilers. But the chief advantage of my invention is the ability by its use to burn
the bagasse in a furnace of sufficient capacity to obtain the full generation of its
heat, and then utilize that beat to the best advantage with the least amount of boiler
surface.
I make no claim to arranging a boiler upon one side of a bagasse burner as this
has been done in several instances. The essential purpose of my invention is to
provide an arrangement of the boilers whereby they shall be brought into the
closest possible proximity to a bagasse burner of sufficient size for efficient combustion,
whereby the maximum temperature developed by the combustion of the bagasse shall
be expended in the generation of steam without material loss or waste.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed as communicated to me
I declare that what I claim is :-
1. A bagasse burner having a boiler furnace upon the side thereof said boiler

page_text: furnace being without grate-bars and provided with tuyeres in its side walls the
bagasse burner having openings in its side walls communicating with the boiler
furnace and provided with dampers or gates adapted to close said openings
substantially as described.
2. In an apparatus to burn damp bagasse, the combination of a bagasse furnace
between the boilers auxiliary furnaces under the boilers having side tuyeres in the
furnace walls a draft door and furnace door, an air heater, and dampers to turn on
or off the waste heat from heater and thereby change the blast from hot to cold or
the reverse.
3. A bagasse-burner having openings in its side walls, in combination with boiler
furnaces with which said openings communicate, said boiler furnace being arranged each
beneath a series of boilers and having no grate-bars all of said furnaces being supplied
with tuyeres in their side walls an air heater and dampers whereby the waste heat
may be driven over said heaters or diverted therefrom and carried directly to the
chimney substantially as described.
4. The combination of a bagasse furnace with auxiliary furnaces for forced blast
each furnace being connected by distinct air passages to a reservoir of forced air
provided with blast gates to regulate the supply of air to each furnace substantially
as described.
5. A central furnace for burning bagasse situated between two or more steam
boilers and supplying heat to each boiler of the series as described.
6. A central furnace for burning bagasse situated between a series of steam boilers,
the boiler setting being arranged with dampers to admit and regulate the waste heat
from the boilers to the heater and with exit holes provided with dampers leading direct
to the chimney.
7. The combination of a central bagasse furnace with steam boilers upon each side
of the furnace with openings and dampers in the boiler walls to admit or close off
the waste heat from an air blast heater or turn it direct to the chimney and an air
blast heater and air forcer.
8. An air heater without bends or turns composed of straight tubes connected to
air boxes and provided with dividing or heat diverting plates through which the tubes
pass for the purpose of deflecting the heat substantially as described.
9. A bagasse furnace arranged as described to receive a cold or hot blast by means
of regulating dampers to let on or shut off waste heat from an air blast beater, or to
let the heat pass direct to chimney without passing through the beator.
Dated this Fifth day of August 1889.
CRUIKSHANK & FAIRWEATHER,
62, Saint Vincent Street, Glasgow, Agents.