Improvements in Furnaces for Steam Boilers, and in Apparatus for Supplying Fuel thereto.
Year: 1895

page_text: Date of Application, 4th Dec., 1895-Accepted, 18th Jan., 1896
COMPLETE SPECIFICATION.
Improvements in Furnaces for Steam Boilers, and in Apparatus for
Supplying Fuel thereto.
I GEORGE LONGWORTH of 163 Worsley Road Little Hulton near Bolton 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 relates to improvements in the construction of the furnaces of
steam boilers for the purposes of economizing the consumption of fuel therein and
consuming the smoke, and in "mechanical stokers" or apparatus for supplying
fuel to such furnaces.
The nature of my said invention and the manner in which the same is to be
performed or carried into practical effect will be readily understood on reference
to the two sheets of illustrative drawings hereunto annexed and the following
explanation thereof.
Fig. 1 on Sheet 1 of the drawings is a vertical longitudinal section of a furnace
and mechanical stoker constructed according to my invention and shown as applied
to a steam boiler and Fig. 2 is a horizontal section of the furnace just above
the fire bars. Fig. 2 is a transverse section on an enlarged scale of one of
the fire bars. On Sheet 2 of the drawings Fig. 3 is a front view (partly in
section) of a steam boiler with a pair of furnaces and mechanical stoker constructed
according to my invention and Fig. 4 is a plan view (also partly in section) of the
mechanical stoker for supplying the said furnaces with fuel a is part of the boiler,
the flues, d the fire doors and c the fire bars.
These fire bars (see Sheet 1 of the drawings) are each made in one length
and are supported by bearers at each end only, thus dispensing with the usual
middle bearer wbich usually causes the fire to lie black across the centre for want of
oxygen.
The bars c are slotted or recessed through at or near the front near the fire
doors as shown at Fig. 2 and are provided with rocking pieces d+ (see Fig. 1)
which are hinged at one end and can be operated by hand by means of levers e
for breaking up the fire and loosening clinkers without opening the furnace doors.
The back part of the fire bars c is recessed partly through (see section Fig. 2)
and is provided with side openings e+ for the admission of air. Some of the
bars are also provided with a chamber or tube f running lengthwise and serving
to convey warm air, or steam and air, into the hollow bearer whence it is
conveyed by two pipes h (one on each side) and discharged into the conical
chamber i in the bridge k of the furnace, whence the air &c. escapes and meeting
the smoke and gases from the fuel burns the smoke and ensures the perfect
combustion of the gases.
These pipes (instead of being inside the furnace) may be carried through the
plates into the water space, and be provided with means for allowing of expansion
and contraction.
Two or more pipes (not shown on the drawing) may convey steam into this
chamber i and act as a steam jet to induce a current of air to pass through the
fire bars c and thus improve the combustion. The pipes may be provided with
valves (see Fig. 1) which may be closed by springs and opened by rods from the
front, or vice versa, so as to diminish or increase the draught as may be found
desirable.

page_text: The bars c may be movable or stationary. In the former case three-throw cams
or tappets m (or cranks or excentrics) may move them backwards in sets, and
then one cam or tappet n (or more than one such cam or tappet) will move all the
bars forwards together carrying the fuel with them.
The side bars c++ are notched as shown in the plan view Fig. 2 to receive the
ends of the back bearer g and prevent it from moving out of position, thus dispensing
with holes being drilled through the boiler plates.
The fuel may be placed in front of the fire by hand, in which case the mechanical
stoker will be dispensed with, and the fire door may be set in a brick arch (as
shown by the dotted lines in Fig. 1) which forms the entrance to the furnace, and
this may be supplemented by one or more arches o within the furnace which will
concentrate the flames just before meeting the hot air &c. from the conical chamber i
in the bridge. The opening under the hollow bearer g is closed by a damper p
which may from time to time be opened for clearing out dust and ashes accumulating
in front of the bridge k.
6
The mechanical stoker" (when used) is constructed as follows: A hopper q
over the mouth of each furnace is placed above a shoot r (see Fig. 1) the opening
to which is regulated by means of a sliding plate s fitted with and worked by a
screw and hand wheel t. In this shoot works a shovel u which is connected by a
rod v hinged or otherwise fixed to a piston w in a small steam cylinder & which is
supplied with steam from the boiler or other convenient source. The piston rods v
are slotted and through the slots (see Fig. 4) work the longer arms of two levers y,
the shorter arms of which are acted upon by three-throw tappets or cams, which
are caused to revolve by bevil gearing or otherwise.
The action of these tappets or cams is to draw back the shovels u causing the
piston w to compress the steam in the cylinders and as soon as the point of each
cam or tappet escapes from the end of the lever, thus releasing the same the
compressed steam in the cylinder expanding suddenly forces the piston w forwards
causing the shovel u to throw the fuel which has accumulated in front of it onto
the fire bars c. The fire door d is placed in front of the stoker so that the working
of the apparatus may be examined and regulated whilst at work.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is
First. The combination with the recessed fire bars of the rocking pieces hinged
at one end and actuated by levers from the front to break up the fire and loosen
the clinkers.
Secondly. The fire bars provided with a chamber or tube running lengthwise
and communicating with hollow bearers at the back end of the bars to receive the
heated air, and convey it through side pipes into a chamber inside the bridge,
through a narrow orifice at the top of which it is caused to issue and mingle with
the flames and gases.
as
Thirdly. I claim the improved arrangement of the "mechanical stoker"
hereinbefore described and illustrated by the annexed drawings and more especially
the method of actuating the shovel by a piston actuated by compressed steam.
Fourthly. I claim the general construction and arrangement of the furnace
and mechanical stoker" substantially as herein before described and illustrated.
Dated thin 2nd day of Doomben 1905
GEO. DAVIES & SON,
4, St. Ann's Square, Manchester, Agents for the Applicant.