IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND FOR Messi
Year: 1866

page_text: LETTERS DATENT to Themes Melden, Engineer, in the employ of
Messieurs Mather and Platt, of Salford, in the County of Lancaster, for
the Invention of "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND FOR
Messieurs Mather and Platt, of Salford, in the County of Lancaster, for
the Invention of "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS AND FOR
Sealed the 19th June 1866, and dated the 3rd February 1866.
PROVISIONAL SPECIFICATION left by the said Thomas Molden at
the Office of the Commissioners of Patents, with his Petition, on the
3rd February 1866.
I, THOMAS MOLDEN, Engineer, in the employ of Messieurs Mather and
Platt, of Salford, in the County of Lancaster, do hereby declare the nature
of the said Invention for "IMPROVEMENTS IN FURNACES FOR STEAM BOILERS
AND FOR OTHER PURPOSES," to be as follows:-
My Invention consists in giving a lateral to-and-fro and up-and-down
motion to the fire-bars of furnaces, and in constructing the front of the bridge
with diagonal fire-bars, under which is an air chamber to promote the com-
bustion of the fuel and to consume the smoke. A convenient mode of giving
the requisite motions to the fire-bars is as follows:-The fire-bars are sup-

page_text: ported on side bars with guides; these side bars form stays between the dead
plate and the back plate or bridge, and the lower surface of each fire-bar is
made with an open fork. These forks fit on cams or excentrics fixed to a
shaft running under the grate. By turning this shaft partly round when
required in contrary directions, either by hand or power, the grate bars are
moved alternately to and fro and up and down, thus preventing the formation
of clinkers and admitting the requisite supply of air to increase the combustion
of the fuel. The diagonal grate bars in front of the bridge cause an accumu-
lation of bright red fire near the bridge, and the spaces between these
diagonal grate bars supply the requisite quantity of atmospheric air for the
combustion of the smoke. The air chamber under the diagonal grate bars is
furnished with a valve to regulate the supply of air.
My Invention also consists in making grate bars with an angle-shaped top
and with teeth on the sides of the angle. These improved furnaces are
applicable to the boilers of stationary, marine, and locomotive engines, and to
gasworks, dyeworks, and other purposes where furnaces are or may be
employed.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Molden in the Great Seal Patent Office on the
2nd August 1866.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
MOLDEN, Engineer, in the employ of Messieurs Mather and Platt, of Salford,
in the County of Lancaster, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Third day of February, in the year of our Lord
One thousand eight hundred and sixty-six, in the twenty-ninth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said Thomas Molden, Her special license that I, the said Thomas Molden,
my executors, administrators, and assigns, or such others as I, the said Thomas
Molden, 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
FURNACES FOR STEAM BOILERS AND FOR OTHER PURPOSES," upon the condition
(amongst others) that I, the said Thomas Molden, my exécutors or adminis-

page_text: trators, 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 Thomas Molden, do hereby declare
the nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement (that is to say) :-
My Invention consists in giving a lateral to-and-fro and an up-and-down
motion to the fire-bars of furnaces, and in constructing the front of the bridge
with diagonal fire-bars, between which air is admitted from an air chamber to
promote the combustion of the fuel and to. consume the smoke.
And in order that my Invention may be fully understood and readily
carried into operation I will proceed to describe the accompanying Sheet of
Drawings, reference being had to the figures and letters marked thereon.
a
Figure 1 is an end view of my improved furnace; Figure 2 a longitudinaj
section, Figure 3 a transverse section, and Figure 4 a plan of the same.
is the internal flue of an ordinary steam boiler; b, the firing door, which is
provided with slots and with a register sliding plate c to admit air when
required; d is the dead plate, and e the bridge; these parts are made as usual.
The fire-bars f, f, are made with fine teeth to prevent the adhesion of clinkers,
and they rest upon the slide bars g, g, which have slanting tops, as shewn in
Figure 3; these slide bars have projections cast upon them to guide the fire-
bars! Each fire-bar is made with an open fork at the under side, and these
forks fit upon the cams or eccentrics h, h, fitting on the square shaft i, the
ends of which are round and are supported in bearings in the dead plate d
and back plate j; the shaft i is also supported at intervals by narrow inter-
mediate bearings. In placing the cams or eccentrics h on the shaft i, they
must be placed alternately with the higher and lower sides uppermost, as
shewn in Figure 2. To the outer end of the shaft i is fixed the lever k when
the shaft is to be moved by band, or a pulley or wheel when it is moved
by power. One end of the grate bars has a projection which is kept clear of
the side bar l, the other end passes under the side bar m; the object of these
two side bars, which are secured to the dead plate d and back plate j, is to
prevent the coal and cinders dropping down beyond the ends of the fire-bars.
At the front of the bridge are the diagonal fire-bars n; these bars are angle
shaped and toothed at the top, and they rest in a recess in the back plate j
Each bar is
and in a groove in the upper part of the air chamber o.

page_text: independent of the others, and sufficient space is allowed above and below for
expansion and contraction. Within the air chamber o is the pipe p, into
which a jet of steam is injected when required. The steam is conveyed through
the pipe 9, passing under the fire-grate, and the steam passes through the hole r
in the bridge.
The mode of operation is as follows:-When the lever his moved up
and down or when the shaft is turned round, the eccentrics h, acting on the
sides of the forks at the under sides of the grate bars f, impart a slight
lateral motion to the bars, and this lateral to-and-fro motion is also converted
into a vertical up-and-down motion by the slanting surfaces of the slide
bars 9, 9, on which the fire-bars rest. These up-and-down and lateral
motions are given in opposite directions to each alternate fire-bar over the
entire surface of the grate, thereby preventing the formation of clinkers and
allowing the requisite supply of air to ascend between the fire-bars for the
entire combustion of the fuel. In some cases it is sufficient to, move the fire-
bars between each fresh application of fuel, and in other cases it is desirable
to keep them constantly in motion, the amount of motion depending upon the
nature of the firing and the quality of the fuel. The diagonal grate bars n
in front of the bridge canse an accumulation of bright red fire near the
bridge, and the air which penetrates between the bars n, in combination with
the steam admitted through the pipe q, increase the draught and effect a
perfect combustion of the smoke.
The improved furnaces above described are applicable to the boilers of
stationary, marine, and locomotive steam engines, and to gasworks, dyeworks,
and other purposes where furnaces are or may be employed.
Having thus described the nature of my Invention, and the manner of
performing the same, I wish to remark that I am aware that the grate bars
of furnaces have been made to move up and down and laterally to and fro
before the date of this Patent, I therefore make no claim to either of these
motions separately; I would also remark that I do not intend to limit myself
to the arrangements shewn and described for imparting an up-and-down and
a lateral to-and-fro motion to the grate bars, as they may be performed by
many other combinations of machinery; but what I do claim is,―
First, the application of an up-and-down motion combined with a lateral
to-and-fro motion to the grate bars of furnaces.
Secondly, the improved mode of constructing and applying the diagonal
grate bars n near the bridge.
Thirdly, the side bars marked and m, to prevent the dropping down of the
fuel when the fire-bars are in motion.
.

page_text: And, lastly, the general combination and arrangement of the parts forming
my improved furnace as shewn and described.
In witness whereof, I, the said Thomas Molden, have hereto set my
hand and seal, this Thirtieth day of July, One thousand eight hundred
und sixty-six.
THOMAS MOLDEN. (L.S.)