IMPROVEMENTS IN APPARATUS FOR BURNING SAWDust, Shavings, AND OTHER COMBUSTIBLE SUBSTANCES.
Year: 1875

page_text: LETTERS PATENT to Richard Hodson, of the Thames Iron Works
Company, Limited, Blackwall, in the County of Middlesex, Civil
Engineer, for the Invention of "IMPROVEMENTS IN APPARATUS FOR
BURNING SAWDust, Shavings, AND OTHER COMBUSTIBLE SUBSTANCES.'
"
PROVISIONAL SPECIFICATION left by the said Richard Hodson at the
Office of the Commissioners of Patents, with his Petition, on the
1st September 1875.
I, RICHARD HODSON, of the Thames Iron Works Company, Limited,
Blackwall, in the County of Middlesex, Civil Engineer, do hereby
declare the nature of the said Invention for "IMPROVEMENTS IN Apparatus
FOR BURNING SAWDUST, SHAVINGS, AND OTHER COMBUSTIBLE SUBSTANCES," to be as
follows:-
-
This Invention has reference to an improved mode of utilizing saw-
dust and shavings, for which Letters Patent were granted to me August
4th, 1874, No. 2701, and the Invention consists in improvements in the

page_text: apparatus for burning the sawdust, shavings, and other combustible
substances.
The apparatus consists of a hopper for receiving the sawdust to be
used as fuel, and a closed chamber in communication with the hopper
by an opening. An archimedian screw is mounted horizontally in the
hopper and concentric with the opening. The shaft of this screw is
carried by bearings in the opposite ends of the hopper and closed
chamber. An air trunk is in communication with the lower part of the
closed chamber, and a fan or blower of any ordinary or approved con-
struction forces a current of air across the chamber into the trunk.
Fitted to the forward end of this trunk is a metal mouth-piece, which
leads into the combustion chamber of the steam boiler.
This mouth-
piece tapers in vertical section towards the combustion chamber, and it
expands laterally so as to present a broad horizontal opening thereto.
The forward end of the mouth-piece is hinged so that it is capable of
being raised or lowered by means of a hand lever, for the purpose of
delivering the sawdust at different angles as may be desired. Within
the closed chamber is fitted a funnel or hopper with movable sides, in
which is mounted a wheel consisting of a boss with radial blades. The
shaft of this wheel receives motion from a chain which passes round a
pulley on a countershaft, which countershaft is actuated by a worm on
the axlo of the fan taking into a worm wheel keyed fast to it.
The archimedian screw is driven from the same shaft by means of a
chain and pulleys. The shaft of the fan may be driven in any con-
venient manner, but I prefer to use a Brotherwood three cylinder
engine. If now the hopper be charged with sawdust and the screw
shaft set in motion, the sawdust will be delivered into the closed
chamber and on to the wheel enclosed therein. The sawdust falling on
to this wheel will be delivered in regulated quantitics into the air trunk..
Here the sawdust is met by a blast of air which will deliver it in the
form of a cloud into the combustion chamber of the boiler or furnace.
In order to prevent any part of the apparatus being broken by any
jamming of the working parts, the worm on the fan shaft which gears
into the worm wheel on the countershaft is not keyed fast on to the fan
shaft, but is held in place thercon by means of a friction band, which is
capable of being tightened up by a screw.

page_text: Should any of the working parts become set fast, the continued
rotation of the fan shaft would have the effect of running the worm out
of gear with the wheel.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Richard Hodson in the Great Seal Patent Office
on the 1st March 1876.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, RICHARD
HODSON, of the Thames Iron Works Company, Limited, Blackwall, in
the County of Middlesex, Civil Engineer, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the First day of September, in the year
of our Lord One thousand eight hundred and seventy-five, in the
thirty-ninth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Richard Hodson, Her special
licence that I, the said Richard Hodson, my executors, administrators,
and assigns, or such others as I, the said Richard Hodson, my executors,
administrators, and assigns, should at any time agree with, and no
others, from time to time and at all times thereafter during the term
therein expressed, should and lawfully might make, use, exercise,
and vend, within the United Kingdom of Great Britain and Ireland,
the Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN APPARATUS FOR BURNING SAWDUST, SHAVINGS, AND OTHER COMBUSTIBLE SUB-
STANCES," upon the condition (amongst others) that I, the said Richard
Hodson, my executors or administrators, by an instrument in writing
under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what
manner the same was to be performed, and cause the same to be
filed in the Great Seal Patent Office within six calendar months next
and immediately after the date of the said Letters Patent.
NOW KNOW YE, that I, the said Richard Hodson, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by
.

page_text: bottom, and opposite to this opening the feed trunk E connects with the
chamber O* at its front side. The sides of this chamber (see Fig. 5) are
hinged to allow of their yielding to any undue internal pressure, and
they are held in position by means of pressure springs. The blower
discharges a blast of air into the trunk for the purpose of carrying
forward the fuel as it descends from the measuring wheel to the mouth
or discharge end of the trunk, from which the fuel passes in the form of
a cloud or shower into the fire chamber of the boiler to be heated.
•
The axle F¹ of the fan constitutes the main driving shaft of the
apparatus, and it receives its motion from a rotary engine G, Fig. 4, of
any approved construction, the fan axle being preferably an extension of
the axle of the rotating drum of the engine. The motion of this fan or
blower axle F' is transmitted to the axle of the propelling screw in
such manner as to permit of the relative adjustment of their speeds to
suit the supply of air to that of the fuel. The gearing is also so
arranged that should any stoppage occur in the delivery passages, the
motion of the gearing will be automatically arrested.
Secured to the axle F' by a friction clip piece ƒ (see Figures 6 and 7)
is a worm f', which gears into a worm wheel h on a countershaft H, and
serves to transmit the motion of the fan shaft to the propelling screw.
When therefore any obstruction to the rotation of the propelling screw
occurs, the motion of the countershaft Œ will be arrested, and the worm
continuing to rotate will by reason of its gearing into the worm wheel h
be caused to slip endwise on its axle until it works out of gear. On the
obstruction being removed the worm fis to be thrown into gear with
the worm wheel 7, and the action of the apparatus will proceed as
before.
The countershaft H has its bearings in the frame A, A, and keyed to
one end is a chain pulley c, the chain from which passes round a chain
pulley on the axle of the measuring wheel C² for the purpose of
driving the same. By the rotation of the wheel C the fuel discharged
into the chamber C* is delivered into the feeding trunk E. On the
other end of the countershaft H is a differential pulley I for receiving a
chain i that passes to and drives a similar pulley K, keyed on the axle
of the propelling screw D. To allow of this chain being readily shifted
on the pulleys, it is held at tension by a weighted pulley L, the tipping

page_text: of which out of action leaves the chain free to be shifted to a greater or
less diameter of the pulleys, in order to ensure the proper relation between
the amount of fuel and of air blast supplied to the furnace. This will
vary according to the quality of fuel being consumed; and the intensity
of fire required to be maintained will be determined by the speed at
which the apparatus is driven.
In order to bring the apparatus completely under the control of the
attendant, a supply cock or valve m is fitted within his reach to the pipe
M, which supplies steam to the engine G. By turning this valve the
supply of steam to the engine is readily increased or diminished, and
thus the supply of fuel and air may be raised to the maximum or com-
pletely cut off; M¹ is the pipe for leading off the escape steam. The
hinged pieces B¹ of the hopper are connected together by a link b, and a
pin projecting from the side of this link enters the slotted end of a
cranked rock lever N having its fulcrum at n. This crank lever
terminates in a fork N¹ which embraces a cam N2 on the countershaft
H; the rotation therefore of this shaft causes the cam to rock the crank
lover, and thereby vibrate the hinged pieces B¹. By this means the
sawdust falling from the hopper will, in case it should have any tendency
through dampness or otherwise to cake, be caused to deliver freely into
the chamber C, whence it will be discharged as before explained into the
-

page_text: the inclination of the hinged lips is adjusted. The adjustment may be
secured by means of a spring catch or equivalent contrivance taking
into a segment bar affixed to the feed trunk,
It will be convenient to fit the mouth of the trunk with a hinged
cover as at e³ (Fig. 3), to facilitate the removal of any obstruction in the
mouth. The framework A may with advantage be filled in with
panelling, but in that case doors should be provided to give access to the
gearing for the purpose of adjusting the relative speeds of the propelling
scrow and fan.
In applying this apparatus to the heating of a furnace, a fire is first to
be lighted in any convenient manner on the fire-bars, and the sawdust
and chips as they enter the fire chamber from the feed trunk will be
instantly ignited and consumed while in a state of suspension, and the
whole of the interior of the furnace will quickly become one mass of
fire, which will be maintained so long as the supply of fuel and air is
kept up. Thus no residuum will be left either on the bars or in the
furnace flues.
A modification of this apparatus is shown in sectional elevation at
Fig. 8, where in place of the chamber C and measuring wheel 0³, a
shute C is employed for conducting down the fuel to the feed
trunk E. In other respects this arrangement will be similar to that
above described.
Having now set forth the nature of my Invention of " Improvements
in Apparatus for Burning Sawdust, Shavings, and other Combustible
Substances," and explained the manner of carrying the same into effect,
I wish it to be understood that under the above in part recited Letters
Patent I claim,---
First. The arrangement of gearing and differential pulleys for trans-
mitting motion from the motive power engine to the propelling screw,
in such manner that the speed of the propelling screw may be readily
adjusted relatively to the speed of the fan or blower, and the action
of the apparatus arrested should any feed delivery passage become
disabled.
Secondly. The construction of the feed trunk with a hinged tapering
mouth, the lips of which are adjustable, substantially as and for the
purpose above described.

page_text: Thirdly. The arrangement above described for increasing or diminishing
the supply of mixed fuel and air and cutting off the supply at the
pleasure of the attendant.
In witness whereof, I, the said Richard Hodson, have hereunto set
my hand and scal, the First day of March, in the year of our
Lord One thousand eight hundred and seventy-six.