Improvements in and connected with the Furnaces of Steam Generators and other like Furnaces.
Year: 1897

page_text: Improvements in and connected with the Furnaces of Steam
Generators and other like Furnaces.
JOSEPH KNOWLES BROADBENT, of 4, Islington Square, Salford, in the County of
Lancaster, Engineer, do hereby declare the nature of this invention to be as
follows:
This invention, which relates to furnaces such as are used in steam generators,
has been designed with the object of enabling inferior and dirty fuel to be burnt
advantageously therein and especially small coal and coal dust with which small
stones and other similar matters are mixed.
In carrying out my invention, I employ, together or separately, transverse rocking
fire-bars; a fire-brick arch at the back of the furnace; and an open chamber or
receptacle in front of the fire-bridge. I may also employ steam blowers under the
grate and a steam poker or pokers within the furnace with other known accessories.
The transverse fire-bars are comparatively broad and have openings through them
for the passage of air so that each bar is, in effect, a short grid. Each bar is
pivoted at each end to lateral bearers, the pivots being as near as practicable in line
with the back edge of the bar. Below each bar there is a slotted projection
engaging with a corresponding projection on a longitudinal rod. If this rod be
reciprocated, the front edges of all the fire-bars will be raised and lowered succes-
sively. I effect the reciprocation of the longitudinal bar by means of a rotary cam
or otherwise in such a manner that the front edges of the bars are raised slowly and
dropped suddenly. By this movement the ashes and the like are shaken through
the bars and the remainder of the fuel or other substances is slowly transferred to
the back of the furnace. There may of course be a plurality of the reciprocating
bars with each grate.
The open topped recess chamber or receptacle at the back end of the grate may
be constructed of fire-brick with its top front edge about even with the grate
level. It may occupy the whole width of the furnace and have its back wall formed
by the fire-bridge. All substances which fail to be consumed or to drop into the
ashpit, are worked forward from the grate into the chamber whence they may be
wholly or partially removed at suitable periods.
The fire-brick arch may be erected over the whole width of the last described
chamber, and in contact with the boiler flue which it tends to protect at the point
where the heat of combustion is fiercest.
1008

page_text: Improvements in and connected with the Furnaces of Steam
Generators and other like Furnaces.
I, JOSEPH KNOWLES BROADBENT, of 4, Islington Square, Salford, in the County of
Lancaster, Engineer, 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:-
This invention which relates to furnaces such as are used in steam generators,
has been designed with the object of enabling inferior and dirty fuel to be burnt
advantageously therein and especially small coal and coal dust with which small
stones and other similar matters are mixed.
In carrying out my invention. I employ, together or separately, transverse rocking
fire-bars a fire-brick arch at the back of the furnace; and an open chamber or
receptacle in front of the fire-bridge. I may also employ steam blowers under the
grate and a steam poker or pokers within the furnace with other known accessories.
I will describe my said invention more fully with reference to the accompanying
drawings which represent my improvements as applied to a Lancashire boiler.
Figure 1 shews a longitudinal section:
Figure 2 a front elevation:
Figure 3 a sectional plan:
Figure 4 a transverse section taken along the line x-y, Figure 3, and
Figure 5, shews a modification of Figure 1.
Figures 6, 7 and 8 shew in plan, in side elevation and in cross section respectively,
one of the fire-bars.
The transverse fire-bars A, are comparatively broad and have openings B through
them for the passage of air, so that each bar is in effect, a short grid. Each bar
is pivoted at C, by each of its ends, to lateral bearers D, the pivots C being as near
as practicable in line with the back and top edges of the bar as shewn by Figures 6,
7 and 8. Below each bar there is a slotted or equivalent projection E, engaging
with or being engaged by a corresponding projection from a longitudinal rod F.
If this rod be reciprocated, the front edges of all the bars will be raised and lowered
successively. I may effect the reciprocation of the longitudinal bar by means of
rotary cams G on the rocking shaft H, or otherwise in such a manner that the front
edges of the bars are raised slowly and dropped suddenly. The rocking shaft may
obtain its motion from any convenient source through the rods or links I. There
may of course be a plurality of the longitudinal bars under each grate instead of
one only as shewn. By this movement of the fire-bars, the ashes and small solid
waste are shaken and thrown down into the ashpit through and between the bars,
and the remainder of the fuel and solids is slowly transferred to the chamber J
near the fire-bridge.
The open topped recess chamber or receptacle J at the fire-bridge end of the grate
may be constructed, as shewn by Figures 1 and 3, of fire-brick with its top front edge K,
about level with the upper surface of the grate. It may occupy the whole width of
the grate or furnace and have its back wall formed by the fire-bridge L. All the
solids which fail to be consumed or to drop into the ash-pit,-are worked forward by
the motion of the bars into the chamber, whence they may be wholly or partially
removed at suitable intervals and times. The bricks forming the floor of this
chamber are preferably perforated as at j and steam may be blown through them to
prevent adhesion of the clinker.
r
1
11.
The fire-resisting arch M; over the chamber J, may be constructed of fire-bricks
or arched tiles over the whole width of the chamber J and in contact with the

page_text: boiler flue N, as shewn, the plates of the boiler flue being thus protected where the
heat of combustion is fiercest. This arch becomes so highly heated that any com-
bustible gases which reach it from the grate become ignited under it, and thereby
escape of these gases is prevented and the heat of their combustion is utilised.
The grate may be horizontal as shewn by Figure 5 or inclined as indicated by
Figure 1. When the horizontal form is adopted, that part of the front wall of the
chamber which lies below the grate level may be substituted by a door O, Figure 5,
opening into the ash-pit. This door may be opened by means of a chain and the
contents of the chamber be removed by a rake from time to time, the door after-
wards automatically closing by gravity.
The accessories which are old and well known and which may or may not be
employed in connection with my present improvements are, steam pokers and
blowers, Q, and a clock work mechanism R, by means of which the louvres in the
furnace door, opened by the opening of the door, are gradually closed after firing.
Having now particularly described and ascertained the nature of my said in-
vention and in what manner the same is to be performed, I declare that what
I claim is:-
1. In a furnace grate, transverse rocking fire-bars so operated that they are raised
slowly and dropped suddenly, and constructed substantially as and for the purpose
herein before described and as illustrated by the accompanying drawings.
2. In a steam generator or similar furnace, a fire-resisting arch at the back of
the grate and in front of the fire-bridge, in combination with an open topped
chamber or recess immediately below it, constructed substantially as and for the
purpose hereinbefore described and as illustrated by the accompanying drawings.
3. In a steam generator or similar furnace, an open topped chamber or receptacle
at the back of the grate and in front of the fire-bridge, constructed substantially as
and for the purpose herein before described and as illustrated by the accompanying
drawings.
4. In a steam generator or similar furnace, the combination and arrangement of
transverse rocking fire-bars, an open topped receptacle at the back of the grate, and
an arch over the said receptacle, constructed substantially as and for the purpose
hereinbefore described and as illustrated by the accompanying drawings.
Dated this 17th day of December A.D. 1897.
W. E. HEYS & SON,
Agents for the Applicant.