Steam Boiler and other Furnaces.
Year: 1886

page_text: Date of Application, 25th June, 1886.
Specification Accepted, 20th May, 1887.
Steam Boiler and other Furnaces.
We, ALFRED TOLHURST of Gravesend, Kent, Solicitor, CHARLES ALFRED
GLAZBROOK of, 7 Sundorne Road, Charlton, Kent, Engineer and ABEL PHILBEY
of 11 Victoria Road, Perry Street, Gravesend, Kent, Contractor 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 has for its object improvements in fire grates and smoke consuming
apparatus for steam boiler and other furnaces.
The present invention is an improvement on that described in the Specification of
a former Patent No. 16241 in the year 1884. As is there described we employ
hollow fire bars into which air is caused to enter and from which the air issues by
lateral passages and so passes to the fire upon the grate. In order that air may be
more efficiently propelled through such bars by means of a steam jet we make the
passage within the bar to taper and after converging to a point, a short distance in
front of the jet, to diverge again and become larger in sectional area as it passes to
the further extremity of the bar. This divergence may take place rapidly until the
passage attains its full sectional area, and beyond this point the sides of the passage
may be parallel; or else the divergence may take place more gradually and be
continued to the further extremities of the bar. Or in some cases where the bars are
long we apply two steam jets, one at the end and a second at a point about midway in
the length of the bar.
In place also as is described in the said former Specification of forming these bars
at the points where the air issues with lateral nipples which interlock and engage the
one with the other we form the nipples or air exits so as to be independent the one of
the other. In front of the aperture in the side of the bar by which the air issues we
provide an inclined flange or lip which directs the current upwards and above this lip
projecting from the side of the bar, and on a level with its surface we provide a
projecting lug or cover which may either project so far as to come in contact with the
next adjacent bar and be perforated for the passage of the air. Or the lug may be
made narrower to leave a space by which the air may ascend to the fuel on the grate

page_text: between the outer edge of the lug and the side of the adjacent bar. The air can also
escape beyond the ends of the lug and pass upwards, to the fuel.
Sometimes in place of providing an inclined lip as above described to direct the
issuing air upwards we simply pierce the air passage in a diagonal direction.
In order that the bars may be conveniently cleaned we in some cases cast each bar
in two parts an upper and a lower-these parts are hinged together at the end most
distant from the fire door and at the other extremity the upper part of the bar is
supported by the edge of the dead plate whilst the lower part is carried by a cross
bearer which is easily removeable. In this way whenever required the hollow bars
can be opered for cleaning.
We also according to our invention supply air by means of hollow bars, preferably
one on either side of the grate, to metal boxes built into the bridge and which are
provided with outlet channels by which the air in a heated state is delivered at the top
of the bridge. We form this bridge with a passage beneath it closed by a door which
can be opened to remove ashes and beyond we provide another solid bridge to stop
the rush of air which otherwise would occur when the door in the first bridge is
opened to remove clinker and ashes..
We also employ hollow fire bars in connection with upright boilers-In this case
the bars are supported on a hollow ring fixed within the fire box.
The hollow bars which preferably are cast in groups several together are supported
by this ring, they are perforated at the sides for the passage of air to the fuel on the
grate, and at one end they communicate with the interior of the hollow ring so that
air which is forced into the hollow ring in any convenient manner enters the bars and
passes to the fuel.
A portion of the ring which is not required for the supply of bars delivers air into
a pipe which rises up within the fire box to the base of the chimney where through a
perforated ring it delivers the air to the gases as they ascend, thereby insuring very
complete combustion.
In some cases I employ fire bars which extend transversely across the furnace from
side to side; they are supplied with air from one end from a hollow longitudinal bar
or bearer into which air is projected by a steam jet or in other convenient way. The
air enters the bars and escapos by lateral passages to the fuel upon the grate as already
described.
In order that our said invention may be fully understood and readily carried into
effect we will proceed to describe the drawings hereunto annexed.
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of a steam boiler furnace constructed in accordance
with our invention.
-
Figure 2 is a transverse section one half on the line A. A. and the other half on the
line B. B. in Figure 1.
Figure 3 is an horizontal section one half on the line C. C. and the other half on the
line D. D. in Figure 2.
Figure 3 is a vertical section showing the bridge in a modified form.
Figure 4 is a plan of one of the bars.
Figure 5 is a longitudinal section of the same.
Figure 6 is to a larger scale a transverse section on the line E. E. in Figure 4.
Figure 7 is a transverse section on the line F. F. in Figure 4.
Figure 8 is a longitudinal and vertical section on the line G G in Figure 4.
Figure 9 is a longitudinal section showing a modification.
Figure 10 is a transverse section showing another modification.
Figure 11 is a vertical section showing the application of two steam jets.
Figure 12 is a longitudinal vertical section of a hollow fire bar made in two parts
jointed together.
Figure 13 is a vertical section of an upright boiler provided with our fire grate.
Figure 14 is a sectional plan of the same."

page_text: Figure 15 is a plan of a fire grate in which the bars are laid transversely.
Figure 16 is a transverse vertical section of the same.
Figure 17 is also a transverse vertical section and shows a modification.
In Figures 1, 2 and 3 a is the flue of a boiler within which the furnace is -con-
structed. b. b. are the fire bars; in Figure 1 they are represented as each made in.
two lengths. is the bridge and c c the metal boxes built into the bridge. 22 are
the outlets by which the heated air issues at the crown of the bridge. d. d. are
channels or special fire bars by which air is supplied to the boxes c c¹. e is a steam
pipe on which are nozzles e e¹ directing jets of steam into the mouths of the hollow
fire bars and channels d. d.
In Figure 3 the bridge c. on which the boxes c¹ are supported has an opening
through it at the lower part and this is provided with a door X which is opened to
rake out any ashes which may pass over the bridge c. Y is a second bridge to check
the rush of air when the door X is opened.
The fire bars are shown more in detail by the Figures 4 to 8.
The double cone at the mouth of the bar to cooperate with the steam jet and render
it more efficient in driving air into the bar is shown at b¹.
The air forced in by the jet issues at the apertures 62 and it is then directed upwards
by the inclined lip 63 and it passes out to the fuel on the grate by the apertures 61*,
in the lug or cover b', also by apertures 61xx, beyond the ends of the lug.
Figure 9 shows an arrangement differing only in form from the preceding. In
Figure 10 a simple oblique passage through a boss on the side of the bar is substituted
for the lug and lip ba and b
In Figure 11e is an additional steam nozzle inserted into the bar near the centre
of its length to urge the air forward-the double cone to cooperate with this steam jot
is marked b*.
In Figure 12 a short bar is shown divided longitudinally, by removing the front
bearer the under part of the bar can be lowered to the position indicated by dotted
lines. is a lug to rest on the dead plate and support the upper part of the bar.
In Figures 13 and 14 g. g. are hollow bars cast in groups, and with lateral apertures
for the escape of air to the fire-h. is the hollow ring which supports the bars.
Air is forced into this ring and by holes provided for the purpose it passes out from
the part into the interior of the bars. i is an upright pipe communicating with the
part of the ring and receiving air from it. The pipe i, delivers the air by suitable
perforations to meet the products of combustion where they enter the flue k.
In Figures 15, 16 and 17, l. l. are hollow fire bars laid transversely to form a fire
grate; they are provided with apertures for supplying air to the fuel as already
described. m, is an air channel which feeds and also supports the bars, air is forced.
into it by a steam jet.
Having now particularly described and ascertained the nature of our said invention
and in what manner the same is to be performed we declare that what we claim is :-
1. A fire grate consisting of bars which are hollow and through which air is
supplied to the fire and which are tapered interiorly so that the interior cavity
increases in dimensions from the entrance towards the exit apertures substantially as
described.
2. A hollow fire bar having holes in its sides and deflecting plates or lips and lugs
in front of the holes to distribute air to the fuel substantially as described.
3. A hollow fire bar having bosses or projections on its sides and passages through
such bosses or projections and directed obliquely upwards substantially as described.
4. A hollow bar divided into two parts longitudinally and jointed so that the
lower part can open away from the upper in a downward direction substantially as
described.
5. Hollow fire bars with lateral apertures supported on a hollow ring through
which air is forced; and in combination with the same a pipe rising from the ring
and supplying air at the base of chimney. substantially as described.

page_text: 6. A hollow bar or channel through which air is forced by a steam jet into a box
extending partly across the bridge such box having air outlets delivering the air at
the crown of the bridge substantially as described.
7. The combination of a bridge with air outlets at the crown, a passage with a door
beneath this bridge and a second bridge beyond substantially as described.
8. The combination in a fire grate of a longitudinal hollow bearer into which air is
forced by a steam jet or by other means and transverse hollow fire bars supplied with
air from the hollow bearer and delivering it by lateral apertures to the fuel on the
grate substantially as described.
CARPMAEL & Co.,
Agents for the Applicants.