IMPROVEMENTS IN FURNACES OR FIRE PLACES, CHIEFLY DESIGNED FOR STEAM BOILERS
Year: 1881

page_text: LETTERS PATENT to John Lart, of St George's Square, Pimlico, in the
•
rr
County of Middlesex, for an Invention of IMPROVEMENTS IN FURNACES
OR FIRE PLACES, CHIEFLY DESIGNED FOR STEAM BOILERS." A communi-
cation from abroad by Clark W. Doten, of Boston, Massachusetts, United
States of America.
".
PROVISIONAL SPECIFICATION left by the said John Lart at the Office
of the Commissioners of Patents on the 8th January 1881.
"
JOHN LART, of St. George's Square, Pimlico, in the County of Middlesex.
IMPROVEMENTS IN FURNACES OR FIRE PLACES, CHIEFLY DESIGNED FOR STEAM
BOILERS." [A communication from abroad by Clark W. Doten, of Boston,
Massachusetts, United States of America.]
My Invention relates to improvements in furnaces for steam boilers and the like,
the chief feature of the said Invention consisting in the employment of a series of
wheels and segments of wheels placed upon parallel shafts, and operated in the
manner hereinafter specified.
The said Invention provides amongst others the following advantages, that is to
say: Economy in time and labour is secured, one stoker or attendant being able
to clean a great number of such furnaces, even under very disadvantageous circum-
stances, as, for instance, in sea-going steamers, in which. (especially during rough
weather) great difficulties have been experienced in this respect. There is also an
economy in fuel, for the reason that no coal capable of burning and furnishing
heat-is removed from the furnace together with the ashes and clinkers, as is
frequently the case when ordinary. furnaces are being raked out; moreover, perfect
combustion of the fuel takes place upon the whole surface of the grate, as all parts
thereof are kept constantly clear, and there is no accumulation and conglomeration
of coal and clinkers upon any part. In a furnace embodying my Invention, there
is no necessity for frequent opening of the door, and the consequent loss of heat by
the entrance of currents of cold air is therefore avoided; and, furthermore, I avoid
the frequent expansion and contraction of the boiler plates which occur through
variations in the temperature produced by the drawing of clinkers necessary when
grates of the ordinary construction are employed. By obviating these variations

page_text: "
of temperature, I am also enabled to maintain the steam in the boiler at an even
pressure, and thus ensure steady and even working of the engine or machine with
which the boiler is connected.
In carrying the said Invention into practice, I provide a frame across which a
series of shafts is arranged, having their bearings in the side plates of the said
frame. Upon the said shafts are mounted the wheels and segments hereinbefore
mentioned, which I construct as follows, that is to say:-Each wheel has a broad
boss or hub from which projects a circular web forming the wheel body. Around
the entire periphery of this web are placed cross-pieces, between each two of which
there is a space. The segments are constructed in the same manner as the wheels, 1
but the face of the cross-pieces thereof is preferably grooved so as to allow a certain
quantity of the ashes to rest in the grooves, and thus to protect the said cross-
pieces against direct action of the fire. In some cases I may also groove the face.
of the cross pieces of the wheels. The segments and the wheels are placed
alternately upon the shafts. The wheels are fixed or fast upon the shafts, and ]
revolve therewith, but the segments are loose so that they shall not revolve. By
providing segments alternately with the wheels, a more even surface is obtained
than would otherwise be the case. In some cases the wheels and segments may be.
made or furnished with inclined or angular edges or pieces instead of being provided
with the cross pieces above described. The hubs of the wheels and of the segments 2
being wider than the pieces across their periphery,' there will be a space-between
each wheel, and the segment or segments at its side or sides, whereby ample facility
is afforded for the passage of clinkers and ashes into the ash-pit, moreover, the
spaces provide means for the entry of air. "
At the upper part of each end of the frame I provide a perforated guard-plate,
which prevents coals or clinkers passing between the frame and the surface upon
which the combustion of fuel takes place. Worm-wheels are keyed upon one end
of each of the shafts carrying the wheels and segments. I also provide screws or
worms upon a longitudinal shaft placed along the outside of the frame, said worms
gearing with the worm wheels and actuating the same. Bearings for the shaft s
carrying the worms are provided on the outside of the frame. A ratchet wheel. is
securely fixed upon the screw or worm shaft, and a pawl takes into the teeth of
the said shaft wheel. This pawl is fixed upon a hand-lever loosely mounted
upon the screw or worm shaft, and serves to rotate this shaft when the hand-lever
is oscillated.
The screw or worm shaft being operated, rotation of the wheels is caused,
whereby the fuel upon the grate is agitated, and a grinding and sifting action is
exerted upon the clinkers, whereby they together with the ashes will be caused to
escape to the ash-pit, and the fire will be constantly maintained in a bright and
clear condition.
I may in some cases modify the means for operating the shafts which carry the
wheels and segments, that is to say, instead of driving each separately by means
of worm gearing, I may provide the same with toothed wheels meshing with each
other, and drive the first wheel in any convenient manner.
In small furnaces I prefer to operate the wheels by hand, and from time to time
as may be required. In large furnaces however, as, for instance, those of sea-going-
steamers, I prefer to use steam power for this purpose, and provide the apparatus
with suitable gear therefor. The power in this case may either be taken from
the ordinary engine, or a donkey engine may be employed for furnishing the
same.
Although I have described an arrangement chiefly applicable to steam-boiler-
furnaces, it is evident that my Invention can readily be adapted to furnaces of
other kinds. A description of such adaptations is however not necessary, as any
necessary modifications will be apparent."
6

page_text: SPECIFICATION in pursuance of the conditions of the Letters, Patent filed by
"
the said John Lart in the Great Seal Patent Office on the 6th July
1881.
JOHN LART, of St. George's Square, Pimlico, in the County of Middlesex.
'IMPROVEMENTS IN FURNACES OR FIRE-PLACES, CHIEFLY DESIGNED FOR STEAM-
BOILERS." A communication from abroad by Clark W. Doten; of: Boston,
Massachusetts, United States of America.
My Invention relates to improvements in furnaces. or fire-places for steam-
boilers and the like, and consists chiefly in the employment of a series of wheels
and segments placed upon parallel shafts, and operated in the manner hereinafter
described.
By the said Invention time and labor are economized, as one stoker or attendant
will be able to clean a great number of such furnaces, even under very disadvan-
tageous circumstances, as, for instance, in sea-going steamers, in which (especially
during rough weather), great difficulties have. been experienced in. this respect;
fuel. is economized, for the reason that no coal capable of burning and furnishing
heat is removed from the 'furnace together with the ashes and clinkers, as is
frequently the case when ordinary furnaces are being raked out; moreover, perfect
combustion of the fuel takes place upon the entire surface of the grate, as all parts
thereof are kept constantly clear, and there is no accumulation or conglomeration
of coal and clinkers upon any part.. In using a furnace embodying my Invention
there is no necessity for such frequent opening of the door as with ordinary
furnaces, the consequent loss of heat by the entrance of currents of cold air being
therefore avoided; furthermore, I obviate the frequent expansion and contraction
of the boiler plates due to variations of. temperature caused by the removal of
clinkers when grates of the ordinary construction are employed. By obviating
these variations of temperature. I am also enabled to maintain the steam in, the
boiler at uniform pressure, and thus ensure the steady and even working of the
engine or machine with which the boiler is connected.
.
My Invention is illustrated in the accompanying Drawing, in which
Figure 1 is a plan of my improved furnace or fire-place, and
Figure 2 is a longitudinal vertical section of the same on the line x, x,
Figure 1.
Figure 3 is a side elevation of the gearing for actuating the wheels hereinafter
described, the rear furnace wall being shewn in section.
Figure 4 represents in vertical transverse section and in side elevation one of
the said segments.
Figure 5 represents in side elevation and in central transverse section one of the
said wheels.
Like letters indicate the same parts throughout the Drawing.
a, a, are the walls of the furnace or fire-place, and 'b is a frame arranged
therein. The side plates of this frame support a series of shafts c, d, of which
there may be any desired number. The shafts c carry the wheels e, and the shaft
The
or shafts d carry the segments f. These wheels e are fixed on the shafts c.
said wheels are constructed as follows, that is to say :-Each wheel has a broad boss
or hub e', from which projects the web e² constituting the wheel-body. Around
the entire periphery of this web I arrange a series of cross-pieces e³, which
preferably extend on either side of the said web, as shown, and between which a
space e' is left, as clearly illustrated in Figures 2 and 5 of the Drawing. The
segments f which are loose upon the shaft or shafts d, and therefore do not revolve
with the same, are provided with cross-pieces f¹ similar to those of the wheels e,

page_text: and also have bosses f2. similar to the bosses e¹. These bosses e¹ and f' are wider
than the cross pieces e³ and f1, so that when the wheels and segments are placed
upon their respective shafts there will be ample space between each two of the
said pieces, as shewn at e* and f*, to permit the passage of clinkers and ashes into.
the ash-pit, and also to allow of the entrance of air to facilitate the combustion of
the fuel sustained by the wheels e and segments f.
The wheels e are preferably so fixed upon the shafts e that the cross-pieces e³
of one wheel are in line with the spaces e between the cross-pieces. of the adjacent
wheel, and the cross-pieces f¹ of the segments f are also preferably arranged in a
similar manner, all as shewn in Figure 1.
To impart rotation to the shafts c carrying the wheels e, and thereby prevent the
formation of clinkers during the combustion of the fuel, I prefer to employ the
gearing represented in the Drawing, that is to say, upon a suitably arranged
driving shaft g I secure a toothed wheel g' which gears with a wheel' h fixed upon
the shaft c of the first series of wheels e. This wheel gears with a wheel i on
the shaft & carrying the segments, and through the said wheel imparts motion
to a wheel j fixed upon the shaft c of the second series of wheels e.
:
In small furnaces I prefer to operate the driving shaft g by hand; and at
intervals as may be required, but in large furnaces, as, for instance, those of sea-
going steamers, it is advantageous to use steam power for this purpose, and to affix
a pulley g* to the said shaft to be driven by a belt from the engine or engines of
the steamer or from a separate donkey engine or other motor.
By imparting a rotary motion to the said wheels e the fuel resting upon the
same and also upon the segments is agitated, and a grinding and sifting action is
exerted upon the clinkers, whereby they, together with the ashes, will be caused to
fall into the ashpit, thus ensuring the maintenance of the fire at all times in a
bright and clear condition.
'
At the front and at the rear end of the frame b I provide a perforated guard-
plate k, which prevents the passing of coals or clinkers between the said frame
and the upper surface of the wheels and segments upon which the combustion of
the fuel takes place.
To prevent the entrance of coal or clinkers into the space enclosing the gear-
wheels and the consequent clogging of the same, I prefer to cover the said space
with an inclined shield or perforated plate, the lower edge of which rests upon the
frame b, and the upper edge against the brick work forming the outer wall of the
said space.
If desired the cross-pieces f¹ of the aforesaid segments f may be grooved or
serrated to permit a small quantity of ashes to rest in the grooves therein to
protect such cross-pieces against the direct action of the fire, and in some cases the
cross-pieces of the wheels e are grooved or serrated in a similar manner. Moreover
in some cases the said wheels and segments may be furnished with inclined or
angular edges instead of with cross-pieces as above described, and instead of the
wheels e being revolved by means of gear-wheels as above described they may be
actuated by worms arranged upon a shaft extending on the outside of the frame b
from front to rear of the furnace, and adapted to engage with worm-wheels
keyed upon one end of the shafts c. This shaft is preferably provided with a
ratchet-wheel at its forward end so that by operating a lever provided with a pawl
which actuates the said ratchet-wheel, the said shaft and consequently the
wheels e may be turned to the desired extent.
Having thus fully described the said Invention as communicated to me by my
foreign correspondent, and the manner of performing the same, I wish it understood
that although I have herein above described my improvements as chiefly applicable
to steam-boiler furnaces, it is evident that the same can be readily. adapted to other
furnaces, and that instead of arranging the rotating wheels e adjacent to each
other, and side by side upon a shaft, I may arrange a stationary segment similar
to those above described between each pair of the said wheels throughout the

page_text: entire area of the furnace-grate without departing from the spirit of my Invention,
and I claim,
First. In a furnace and forming part of the same the wheels and segments
constructed with the hub, the web, and the cross-pieces, substantially as above
set forth, and combined and operating as and for the purposes specified.
Second. The combination with the said wheels of means for rotating the same,
substantially as above set forth and for the purposes specified.
Third. In a steam-boiler or other furnace or fire-place, a grate consisting of the
guard-plates and the series of stationary segments in combination with rotating
wheels adapted to be revolved by suitable gearing, substantially as above set forth
and for the purposes specified.
In witness whereof, I, the said John Lart, have hereunto set my hand
and seal, this Thirteenth day of June, in the year of our Lord One
thousand eight hundred and eighty one.
JOHN LART. (L.S.)