Improvements in Furnaces, in Air Heating Arrangements, and in Steam Generators in connection therewith.
Year: 1892

page_text: Date of Application, 12th Apr., 1892-Accepted, 9th July, 1892
COMPLETE SPECIFICATION.
[Communicated from abroad by THE BABCOCK AND WILCOX COMPANY, of
30, Cortlandt Street, in the City, County, and State of New York, United
States of America.]
Improvements in Furnaces, in Air Heating Arrangements, and in
Steam Generators in connection therewith.
I, HENRY HARRIS LAKE, of the firm of Haseltine Lake & Co., Patent Agents,
45 Southampton Buildings, in the County of Middlesex, 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 that type of furnace specially constructed for the use of
green bagasse as fuel.
One object of the invention is to improve furnaces of this kind by the provision
of novel features of construction and new combinations or arrangements of parts,
whereby the water tubes of the steam-boiler are brought, as a whole, near to the
bagasse-furnace and exposed to a more uniform heat throughout, without loss of
boiler space, and without sacrificing any portion of the power. Another object of
the invention is to provide a bagasse furnace having such construction that the
products of combustion will undergo a further combustion in the boiler chambers,
and produce a more intense and uniform heat, whereby the full heating power of
the fuel and the maximum power of the boilers will be rendered available.
A further object of the invention to provide a bagasse furnace having a central
combustion-chamber and lateral boiler-chambers, arranged on both sides, in which
the heating tubes are arranged so as to be heated with substantial uniformity, and
exposed to the hottest portions of the blast, and tubes being arranged in closer
proximity to the bagasse burner than in the furnaces now in use.
My invention also has for its object the improved arrangement of auxiliary
furnaces, adapted for ordinary fuel, and capable of use either alone, or in conjunction
with the bagasse-furnace; and the combination with the said furnaces of an air
heater of improved construction capable of supplying the bagasse furnace only, or
the auxiliary furnaces, or all three conjointly, as circumstances may require.
My invention consists in the parts and combinations of parts hereinafter set forth.
To enable others skilled in the art to make, construct and use my said invention,
I will now describe the same with reference to the accompanying drawings in which
Figure 1 is a vertical section taken on the line L, M, N, O, Figure 7.
Figure 2 is a central longitudinal section, taken vertically in the line P, Q,
Figure 7 one of the boiler chambers being shown in elevation beyond.
Figure 3 is a transverse vertical section, taken on the line E, F Figure 7.
Figure 4 is a transverse vertical section taken on the line A, B, D, Figure 7.
Figure 5 is a longitudinal section taken on the vertical plane G, H, I, K,
Figure 7.
Figure 6 is a plan view of the furnace.
Figure 7 is a horizontal section, passing through the auxiliary and bagasse
furnaces, boiler-chambers, and air-heaters.
In the said drawings the reference numeral 1 indicates the bagasse burner, or
furnace, which consists of a substantially rectangular structure, provided upon each
side with a false wall 2, (Figure 3) by which a tuyere chamber 3 is formed. Blast-
openings 4 are provided, the air being supplied, in the manner described hereafter,
to a chamber 5, formed in the rear wall of the bagasse furnace. The walls 2
contract the interior of the furnace 1 in one direction, making it narrower than the
combustion chamber 1" which rises to a suitable height above it, the form and size
of said combustion chamber being the same as the furnace 1, below, would be, were

page_text: the walls 2 removed. The top 6 of the chamber is preferably arched. Upon
each side of said chamber is formed an opening 7, which gives communication with
the boiler chamber 8 on that side. The bagasse is supplied by means of an
opening 9 in the arched top of the combustion chamber 1.
The boiler chambers and auxiliary furnaces are alike in structure and a
description of one will answer for both. They consist of structures of masonry of
rectangular form projecting, as to the furnace, entirely in front of the bagasse
furnace and out of line therewith. The auxiliary furnace 10 not only projects
forward out of line with the bagasse furnace, but each is sunk down below the level
of the lateral discharge openings, in order to prevent the grates 12 of said auxiliary
furnaces from being injured by the heat of the bagasse furnace. Each auxiliary
furnace is provided with a door 13 to enable wood or other solid fuel to be fed to
the grate, a clean cut door 14 is also provided. The products of combustion pass
through an opening 15 at the rear of each furnace, over an inclined surface 16 by
which they are directed upward to the forward ends of the water tubes of the
boiler. These furnaces are supplied with hot air by pipes 17 which branch from
blast pipes, described hereafter, and are carried in the side walls of the bagasse
furnace, from the front of which they emerge and are bent laterally to enter the
side walls of the auxiliary furnaces and discharge beneath the grate 12. These
pipes 17 are provided with dampers 18 by which their blast may be cut off at.
pleasure.
In each boiler-chamber I use preferably boilers 19 of the Babcock and Wilcox
type, with two drums. Beneath each boiler I arrange the water tubes 20, having
the arrangement, inclination, and combination to the boiler, well known to those
skilled in the art. These water tubes, however, I arrange in two gangs, decks, and
groups, about fourteen, or perhaps sixteen pipes in width, and built up in height
sufficiently to afford the necessary water space. This arrangement enables me to
place the outer tubes, which are at the greatest distance from the bagasse furnace,
some five to seven tubes nearer to the bagasse furnace than has been possible
when using boilers with three drums and twenty-one tubes wide; while extending
the group of tubes to a higher point, I am able to obtain as great a power as before,
with an economy in the consumption of fuel. The blast in the boiler-chambers is
directed by the bridge walls 21 and flume-bridges 22, which are so well known as to
require no description.
Referring to Figure 1 of the drawings, the products of combustion after
travereing the boiler chambers, pass out at the rear end of each chamber by way of
openings 23 in the end walls. Said walls form part of the enclosure of an air-
heating-chamber 24 arranged transversely to the boiler-chamber. These heaters
are usually of rectangular form, and each contains one, two, or more gangs of
pipe 25. 1 preferably use two gangs of pipe, and insert the ends of one gang into
a closed head or box 26, which communicates with a supply pipe 27. The other
ends of the pipes 25 enter a head, or closed box, 28, which has communication in
common with both gangs. The groups of pipes enter a head 29, which delivers the
air to a pipe 30, by which it is carried to the tuyere-chamber 3. The arrangement
is precisely the same for the other side. The air heating pipes 25 are supplied with
air by a blower 31, the casing of which communicates with the pipe 27.
blower is driven by an engine 32. The pipes 33, leading from the blower to the
heaters, are usually provided with dampers to enable either, or both heaters, to be
cut out. The heated gases after traversing the compartments 24, pass to the stack,
which is not shown in the drawings.
The
The drums of the boiler are provided with man-holes 33, to admit of cleansing
and similar entrances are also provided for the air heaters 24, and boiler chambers.
By placing the auxiliary furnaces in front of the line of direction of the blast
from the bagasse furnace, with their grates below the level of the lateral openings
by which the hot blast passes from the combustion chamber 1 to the boiler
chambers, the grates are wholly withdrawn from the heat and cannot be injured,
when the auxiliary furnaces are not in use.

page_text: The auxiliary furnaces are, as a rule, used separately, being intended to supply
heat to the boilers when bagasse is not to be had, or when for any reason it is
desirable to use other fuel. These auxiliary furnaces can be cooled either by
natural draught through the doors opening beneath the grate, or by a forced draft
through the blast pipes. When these furnaces are used, the dampers in the pipes
leading from the blower to the air heating tubes must be opened and the blower
should be turned slowly to drive air through the tubes in the air-heaters 24, to
prevent them from burning.
In using green bagasse as fuel, I have heretofore attempted to provide a furnace
having water-tube boilers, in which the maximum heating surface should be as near
the bagasse furnace as possible. To obtain large horse-powers 1 have used water-
tube boilers with three drums arranging one boiler on each side of the bagasse-
furnace with water-tubes arranged in a number of series of tubes, each series having
twenty-one tubes. When thus arranged the group of tubes was of such width that
those most remote from the bagasse-furnace received much less heat than the others,
which were nearer to it. I have now adopted the construction and arrangement
shown consisting essentially of boilers of two drums only, with fourteen or sixteen
water-tubes in each series.
I use two groups or gangs of these water-tubes each group containing a suitable
number of horizontally arranged series of tubes, one series above the other. It
will readily be seen that, by this arrangement, I contract the boiler-chambers in
width and correspondingly increase their height, thereby bringing those water-
tubes which are nearest the outer lateral walls nearer to the central bagasse-furnace.
Under the arrangement heretofore in use, each horizontal series of water-tubes
contained twenty-one tubes, and the boiler-chambers had to be wider than those
shown in the drawings, to admit the additional five to seven tubes in each series.
The groups of tubes thus spread, or extended, horizontally, occupied less space
vertically, and the water tubes most remote from the central bagasse-chamber
received much less heat than those nearer. By building up the water-tubes in
both groups, or gangs, in the manner described and shown, I bring the water-tubes,
as a whole, much nearer the central source of heat and thus obtain a boiler which
has as great power as any heretofore used, and in which said power is developed by
less expenditure of fuel. The generation of steam is more economically
accomplished, as the water tubes have a better exposure to, and receive the hottest
portions of, the blast, and regarding the whole number of tubes in each boiler.
chamber as a unit, it will be seen that the exposure to the blast will be of longer
duration, in proportion to the increased vertical space occupied, and the heat will
be more nearly uniform upon all parts of the groups, or gangs.
Having now particularly described and ascertained the nature of the said inven-
tion and in what manner the same is to be performed, as communicated to me by
my foreign correspondent, I declare that what I claim is :-
First. In a bagasse-furnace a combustion-chamber, having lateral openings
communicating with boiler-chambers, arranged on both sides of said combustion-
chambers, and boilers having water tubes arranged in said chambers in groups
of increased height and decreased width whereby the boiler-chambers are narrowed
and the outer water tubes brought nearer the central furnace substantially as
described.
素
Second. In a bagasse furnace, the combination with a combustion-chamber and
with boiler-clambers on both sides of said chamber of water-tubes arranged in two
groups, or gangs of increased height and decreased width as compared to the
structures heretofore used their euds being connected together substantially as
described.
Third. In a bagasse furnace, the combination of a combustion chamber, a boiler,
a double gang or group of water tubes of increased height and decreased width
arranged in boiler chambers on both sides the bagasse-furnace, an air heater and an

page_text: air forcing mechanism driving air through the heater and into the furnace, sub-
stantially as described.
Fourth. In a bagasse furnace, a central combustion chamber having lateral blast
communication with boiler chambers containing water-tubes, and auxiliary furnaces
for solid fuel, arranged in frout of the boilers and below the level of the blast-
openings leading to said boiler, chambers, substantially as described.
Fifth. In a bagasse-furnace, a combustion chamber, a boiler-chamber upon one
side thereof, a blast opening leading to the boiler chamber, and beneath water-
tubes arranged therein, and an auxiliary furnace having its grate beneath the level
of the floor of the boiler chamber, and in front thereof, an upwardly inclined surface
being provided between said grate and floor, substantially as described.
Sixth. In a bagasse-furnace a combustion-chamber, a boiler-chamber beside the
same, a blast opening in the side of the boiler chamber, to admit the blast from the
combustion-chamber, an air heater consisting of two gangs or groups of pipes, both
opening at one end into a common head, or closed box, and at the other end into a
blower-casing and an air-pipe leading to the tuyeres and by a branch to. the
auxiliary furnace, said gangs, or groups of pipes, being enclosed in the heater,
which is traversed by the waste heat going to the stack, substantially as described.
Seventh. In a bagasse-furnace having a central and two auxiliary furnaces, one
on each side of the central furnace and below the level of, and in front of the exit-
openings of the central furnace, boiler-chambers behind the auxiliary furnaces,
water-tubes suspended in said chambers and arranged in two gangs, or groups of
increased height and decreased width, an air-heater traversed by the waste heat
going to the stack, a blower supplying air to the air-heater, a pipe leading to the
tuyeres of the central furnace and branch pipes to the auxiliary furnaces, sub-
stantially as described.
Dared this 12th day of April 1892
HASELTINE, LAKE & Co.,
45, Southampton Buildings, London, W.C., Agents for the Applicant.