IMPROVEMENTS IN OR RELATING TO STEAMBOILER OR OTHER FURNACES FOR BURNING STRAW AND SIMILAR VEGETABLE MATTERS, AS WELL AS COAL AND SIMILAR FUEL
Year: 1885

page_text: I, ALFRED JULIUS BOULT of 323 High Holborn in the County of Middlesex
Engineer do hereby declare the nature of the said invention for "IMPROVEMENTS
IN OR RELATING TO STEAMBOILER OR OTHER FURNACES FOR BURNING STRAW AND
SIMILAR VEGETABLE MATTERS, AS WELL AS COAL AND SIMILAR FUEL (a communi-
cation from John Abell, of Woodbridge, Canada, Manufacturer) and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement:-
The object of the Invention is to construct a steam boiler in which straw or
similar vegetable matter may be used for generating steam as well as coal or
similar fuel now generally adopted for that purpose and it consists essentially in
constructing the boiler with two distinct furnaces or combustion chambers one of
which is constructed in the ordinary manner while the other is specially arranged and
adapted to produce the most perfect combustion of straw or similar vegetable matter,
the said straw furnace being provided with peculiarly arranged dampers and
connected to the coal furnace so that the products of combustion from the straw
will pass through the tubes in the same manner as the products of combustion from
the ordinary coal furnace substantially as hereinafter more particularly explained.
Figure 1, is a perspective view of a steam-boiler, showing the location of the two
furnaces, a portion of the figure being made in section so as to expose sufficient of
the interior to exhibit its special construction.
Figure 2, is an enlarged sectional detail of the door-way through which the fuel
is fed into the straw furnace.
Figure 3, is an enlarged perspective detail of the air chamber arranged to protect
the bottom of the leg of the boiler immediately over the passage-way between the
two furnaces, and at the same time supply air for accelerating the combustion of
the particles of fuel which may escape from the straw into the coal furnace.
Figure 4, is an enlarged cross-section of Figure 3, through X. Y.

page_text: Figure 5, is an enlarged perspective detail, showing the form of the straw
furnace bottom.
Figure 6, is an enlarged cross-section through z, p, of Figure 5.
As the boiler, and furnaces are made in all their parts in the ordinary manner
except in the specific details which are illustrated in the drawings and particularly
described in this specification it is not necessary to exhibit in the drawings the
entire construction of the boiler and its furnaces, it being sufficient to state that all
parts not specially described are to be made in a proper and workmanlike manner
according to the construction of similar or corresponding parts in steam boiler and
other furnaces as now made.
A is an outside view of an ordinary coal furnace or fire box connected in the
usual manner to the cylindrical shell B which is provided with flues of the ordinary
description connecting as usual with the interior of the furnaces or fire-boxes A
The portion of the leg of the boiler, marked C extends below the bracket D which
supports the end of the grate-bars, which however are not shown in the drawing..
This leg C which is hollow, and connects in the usual way to the interior of the
boiler, separates the furnace or fire-box A from the straw furnace E except there is
a passage way between the bottom of the leg C and the ash-pan bottom F which
extends below both furnaces A and E.
The portion of the ash-pan bottom F below the furnace E has a corrugated
plate f placed on top of it so as to catch the burning particles of fuel being consumed
in the furnace E This corrugated plate fis made substantially as shown in Figures 5
and 6 The ends of the plate as shown in Figure 5 are flattened so as to form
bearings to rest on the bottom F while the bearings of the corrugations are simply
ogee in shape, as shown in Figure 6. This peculiar form of corrugated plate, f,
permits its expansion and contraction without injury. As shewn in Figure 2, the
sides of the straw furnace, E, are made double, an air space being left between the
two plates, a, and b, which is provided with fresh air through the holes, c, made in
the outer plate d.
The feed-scoop, G, is rivetted to the inner plate, a, as shown in Figure 2, and is
provided with a door, H, which is hinged at h, and extends at an angle inwardly
so that it will always close by its own gravity; and consequently will not remain
open an instant longer than is necessary to permit the passage of the fuel through
the feed-scoup, G, into the straw furnace, E.
Figures 3 and 4 exhibit the construction of the air chamber, I, J, The portion
of this chamber marked, I, extends to the outside of the furnace, E, and its end or
ends is or are provided with dampers, j, so that the supply of fresh air may at any
time be cut off from the said air chamber. The portion of this air-chamber marked, J,
extends into the furnace, A, and is perforated as indicated so as to permit the
escape of the air from the chamber, J, into the said furnace. It will be noticed that
the bottom of the leg, C, fits into a recess, k, and that an air-chamber, I, J, con-
structed as described forms a complete protection for the bottom of the leg, C,
which might otherwise be injured from the intense heat produced in the passage-
way during the consumption of the fuel within the furnace, E.
Having described the general mechanical construction of the parts of the furnace
involved in this invention a few words will suffice to explain the operation of the
furnace and the specific duty of each particular part.
When the furnace A is to be used, grate-bars of the ordinary kind are placed in
it which bars rest on the brackets D in the usual manner and the furnace A is
manipulated exactly in the same way as though no supplemental or straw furnace E
was attached. When, however the straw furnace E is to be used the grate-bars are
removed the damper. K closed and the other damper L opened, the opening at this
latter damper being protected by fingers I so that the loose fuel which may be
within the furnace E cannot escape while air is freely admitted through the damper
The straw or similar fuel is then fed through the feed-scoop G. and being set on
fire will consume with great rapidity, the supply of fuel being kept up by feeding

page_text: through the scoop G the door H closing instantly every time that the supply of
fuel passes it. The flame from the chamber E passes through the passage-way
below the air chamber I. J. into the furnace A and thence through the tubes in the
ordinary way. As the flame passes upwardly past the perforated bottom J, the
heated air admitted from the said chamber intensifies the combustion so as to
thoroughly consume all particles of fuel carried by the flame which would otherwise
lodge in the ends of the tubes and destroy the satisfactory operation of the furnace
which has been one of the principal defects in other straw-burning furnaces made
previous to this invention.
Having now particularly described and ascertained the nature of my said
invention 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 The perforated air chamber I. J. located on the bottom of the leg C.
between the furnaces A and E substantially as and for the purpose specified.
Second A straw furnace C provided with a feed-scoop G. in combination with
a hinged door H arranged substantially as and for the purpose specified.
Third A straw furnace C provided with a damper L and fingers I in combina-
tion with a corrugated plate f substantially as and for the purpose specified.