AN IMPROVED MODE OF UTILIZING SAWDUST AND SHAVINGS
Year: 1874

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 "AN IMPROVED MODE OF UTILIZING
SAWDUST AND SHAVINGS."
.
PROVISIONAL SPECIFICATION left by the said Richard Hodson at
the Office of the Commissioners of Patents, with his Petition, on
the 4th August 1874..
I, RICHARD HODSON, of the Thames Iron Works Company, Limited,
Blackwall, in the County of Middlesex, Oivil Engineer, do hereby declare
the nature of the said Invention for "AN IMPROVED MODE OF UTILIZING
SAWDUST AND SHAVINGS," to be as follows:-
It has been found in some workshops that sawdust and shavings
accumulate so rapidly as to become a serious inconvenience. Many
attempts have been made from time to time to utilize these matters by
'

page_text: converting them into solid fuel, but independently of the cost of this
conversion it has not been found easy to give them such solidity as
would enable them to be burned in closed furnaces like ordinary fuel. I
have found however that by burning the same in a powdered state (disin.
tegrating the shavings to bring them to the state of sawdust), the furnace
being charged with a continuous stream of such fuel by the impelling
force of a blast of air, I am enabled to keep up an intense fire suitable
for generating steam and for calcining mineral substances. A fire has
first to be prepared in the furnace in any approved manner, and tho
sawdust is then to be fed to the furnace, the rate of supply both of the
fuel and of the air for supporting combustion being determined by the
intensity of fire which is required to be maintained.
The apparatus for conveying the material into the furnace will be
very simple. Thus it may be arranged as follows:-Upon a branch of
the pipe which conveys to the furnace a blast of air from a fan or its
equivalent a hopper is fixed for containing the sawdust or disintegrated
wood, and discharging it at a regulated speed into the blast pipe. The
discharge may be regulated by valves, slides, stirrers, or lifts, worked
automatically, and the intensity of the blast of air passing through the
pipe to the furnace may be similarly regulated by valves so as to ensure
its possessing the requisite force for conveying the material along with
it to the furnace, and being equal to the supplying a proper amount
of oxygen for supporting combustion in the furnace. Suitable mouth-
pieces connected to the blast pipe should also be provided for distributing
the material over a large or small area, as may be desired.
It will be understood that as the fuel is delivered to the furnace in
the form of a cloud, and as it will be ignited while in a state of sus-
pension almost instantaneous combustion will ensue and an intense heat
will be obtained suitable for generating steam in boilers for heating and
melting iron or other metals, and for a variety of other uses.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said Richard Hodson in the Great Seal Patent Offico
on the 4th February 1875.
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 Fourth day of August, in the year
of our Lord One thousand eight hundred and seventy-four, in the
thirty-eighth year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Richard Hodson, Her
special license that I, the said Richard Hodson, my executors, ad-
ministrators, 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 Inven-
tion for "AN IMPROVED MODE OF UTILIZING SAWDUST AND SHAVINGS," 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 tho
Great Seal Patent Office within six calendar months next and imme-
diately 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
the following statement, reference being had to the Drawing hereunto
annexed, and to the letters and figures marked thereon (that is to

page_text: converting them into solid fuel, but independently of the cost of this
conversion it has not been found casy to give them such solidity as
would enable them to be burned in close furnaces liko ordinary fuel. I
have found however that by burning the same in the state in which they
leave the workshop, the furnace being charged with a continuous stream
of such fuel by the impelling force of a blast of air, I am enabled to
keep up an intense fire suitable for generating steam and for calcining
mincral substances. A fire has first to be prepared in the furnace in
any approved manner, and the sawdust is then to be fed to the furnace,
the rate of supply both of the fuel and of the air for supporting com-
bustion being determined by the intensity of fire which is required to be
maintained.

page_text: -
screw B is driven through bevil gearing L from a pulley shaft M. If now
the hopper A is charged with sawdust and the screw shaft B is rotated, saw-
dust will be delivered into the cylindrical cago C, which rotating with
the scrow shaft will deliver the sawdust on to the wheel I. Should
however the sawdust contain any matters that will not pass between
the bars of the cage, such as chips or pièces of wood, they will be dis-
charged out at the open end of the cage on to the floor of the clamber A'.
As the cage O and wheel I are geared together, the sawdust falling on
to the wheel I will be delivered in regulated quantities into the air
trunk E. Here, the sawdust is met by a blast of air, which being main-
tained in the trunk will blow the sawdust in the direction of the arrow
and deliver it in the form of a cloud into the combustion chamber.
"
By preparing a fire of shavings or other readily combustible matter in
the combustion chamber, the sawdust as it reaches the chamber will be
instantly ignited, and so long as the supply of sawdust suspended in the
blast of air is continuod a bright firo giving off an intense heat will be
maintained.
When supplying shavings by the above described apparatus to a boiler
furnace the cage C is displaced, provision being made to slide it away
from the opening a towards the end of the screw shaft, as shown by dots
in Fig. 1; the shavings will then be delivered by the screw B directly
on to the wheel I which will deposit them in the air trunk; here meeting
with the air blast the shavings will be carried forward and discharged
through the mouth piece F into the combustion chamber G.
I may find it desirable to fit the hopper A. with stirrers which will
prevent tho sawdust when damp from caking. These stirrers may
consist of two, three, or more rods slightly cranked and mounted trans-
versely of the hopper in bearings in which they will be free to receive
an endway motion. Stirrers of this kind being placed over the screw B
at about the positions indicated by the dotted circles b, Fig. 1, and
receiving a slight endway motion will effectually prevent the sawdust
from caking, and ensure the proper action of the propelling screw B
upon the contents of the hopper.
Having now set forth the nature of my Invention of "An Improved
Mode of Utilizing Sawdust and Shavings," and explained the means-of-

page_text: 'above in part recited Letters Patent I claim, the mode of utilizing saw-
dust and shavings, as above described, for the gencrating of steam in
steam boilers, and for the heating of metallurgical and other furnaces.
In witness whereof, I, the said Richard Hodson, have hereunto
set my hand and seal, the Second day of February, in the
year of our Lord One thousand eight hundred and seventy-
five.