Improvements in Furnaces for Steam Boilers.
Year: 1896

page_text: Date of Application, 31st Dec., 1396-Accepted, 1st May. 1897
COMPLETE SPECIFICATION.
Improvements in Furnaces for Steam Boilers.
I, EDWARD JAMES DUFF, of Glengarriff, Cressington Park, Liverpool, in the
County of Lancaster Engineer, do hereby declare the nature of this invention and
in what manner the same is to he performed, to be particularly described and
ascertained in and by the following statement, that is to say :-
•
My said invention has for its object to construct the furnaces of steam boilers in
an improved manner so as to render unnecessary the frequent removal of the fires
for cleaning purposes and to thereby enable them to be fired continuously, and
obviating the loss of efficiency due to the admission of cold air to the furnace or
furnaces during such cleaning operations.
In my improved furnace instead of fire bars or gratings extending as ordinarily
completely across the furnace I have only part of the width along the middle or
along the sides occupied by gratings which are made with an upward inclination or
curvature, the space or spaces immediately under such gratings being closed by a
plate or plates. The air for combustion or a large part of it is forced or admitted
into the space or spaces and finds its way through the gratings to and amongst the
fuel whilst the ashes or fuel residues gradually descend on each side. of or between
the gratings and can be removed from the ashpit.
And in order that my said invention and the manner of performing the same may
be properly understood, I hereunto append two sheets of explanatory drawings to
be hereinafter referred to, and showing three modificatious of my improved furnace
for steam boilers.
Figure, 1, on Sheet, 1,, of the drawings, is a sectional front elevation, and
Figure, 2, is a longitudinal vertical section of a part of a boiler, having furnaces
made according to one modification of my invention.
Figures, 3, and 4, on Sheet, 2, are transverse vertical sections of separate
modifications of my improved furnace.
In these drawings the same reference letters and numerals are used to mark the
same or like parts wherever they are repeated.
In the modification of my invention shown in Figures, 1, and 2, of the drawings
I provide a hollow dead plate, A, of rectangular section extending across the
furnace mouth and fixed to the furnace front, A 1, in a position to leave a space
between its lower part and the bottom of the furnace shell, A 2. The inner part of
the dead plate, A, is made with a projection, A 3, on which sits one end of a flat
plate, B, the other end of which is built into the bridge, B 1. The flat plate, B,
is made with-longitudinal side ribs, B2, on which sit (their edges being checked to
fit the ribs) transversely placed semi-circular fire bars or gratings, C, occupying
the middle of the space between the dead plate, A, and the bridge, B 1, and
forming with the dead plate, the bridge, and the flat plate, a semi-cylindrical
chamber, D, having segmental openings, C1. The semi-cylindrical chamber, D,
communicates with the interior of the dead plate, A, by an opening, E, and the
dead plate, has an opening in its outer side-closed by a door, G. Fuel, which may
be coal, coke, cinders, cinder refuse, or town or ashpit refuse is fed into the furnace
or furnaces in any suitable known way and is filled up to a level a little higher than
the top of the chamber, D. A pipe, K, is fixed to the front of the dead plate, A,
and through it air for combustion is forced by any suitable known means into the
interior of the dead plate and into the semi-cylindrical chamber, D, from which it

page_text: passes by the segmental openings or spaces, C 1, between the bars, C, to the fuel.
Ashes or fuel residues descend on each side to the space or ashpit, J, from which
they may be removed through an opening closed by a door, J 1, provided for the
purpose, such removal being effected without any or much disturbance of the
burning fuel, and without interfering with the operation of firing which may
therefore be continuous and, by obviating the necessity of frequently." drawing
the fires considerable economy is effected. Fuel or residues entering the
chamber, D, by the segmental.openings, C 1, between the fire bars, C, can be
removed through the opening closed by the door, G.
In cases in which it may be deemed beneficial forced draught is applied in the
ashpit, J.
In some cases it may be found beneficial to admit air at the bridge, B 1, to the
furnace, and for this purpose a small passage, D 1, communicating with the space
above the bridge and with the chamber, D, may be formed in the bridge.
In the case of an externally fired boiler, a water seal trough (not shown) similar
to that described in my Patent Specification No. 7467 of 1893 may be employed.
In the modification shown in Figure, 3, the chamber, D, consists of one casting
of approximately triangular section and is held between the dead plate, (A) and the
bridge, Bl, and made with lateral openings, C 1, through which air for combustion
is forced: Other parts of this modification. not described are similar to the
corresponding parts of the modification previously described.
In the modification shown in Figure, 4, two rows of fire bars or gratings, C,
resting transversely on longitudinal supports, L, between the dead plate, (A,) and
the bridge, B 1, are arranged along the sides of the furnace so as to enclose, with
the furnace shell, A 2, side or wing spaces, M, and to have a middle space, N,
between them. This modification, with regard to other parts is similar to the
modification first described; but the air for combustion is led from the hollow deal
plate, (A); to both wing spaces, M, whence it passes between the bars, C, to the
fuel. Ashes or fuel residues descend into the middle space, N, from the bottom of
which they may be periodically removed without interfering with the firing
operations.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed, 1 declare that what I
claim is :
The improved steam-boiler furnace having part of its width along the middle or
along the sides occupied by gratings which are made with an upward inclination or
curvature, and which have air for combustion passed through them from enclosed
spaces under them, whilst the ashes or fuel residues descend on each side of or
between the gratings substantially as hereinbefore described.
EDMUND HUNT,
Applicant's Agent.