IMPROVEMENTS IN AND RELATING TO FURNACE FRONTS, Doors, DEAD PLATES, AND THEIR' APPURTENANCES
Year: 1880

page_text: LETTERS PATENT to Thomas Henderson, of 13, Harland Road, Higher
Tranmere, in the County of Chester, for an Invention of "IMPROVEMENTS
IN AND RELATING TO FURNACE FRONTS, Doors, DEAD PLATES, AND THEIR'
APPURTENANCES."
PROVISIONAL SPECIFICATION left by the said Thomas Henderson at the
Office of the Commissioners of Patents on the 24th February 1880.
THOMAS HENDERSON, of 13, Harland Road, Higher Tranmere, in the County' of
Chester. "IMPROVEMENTS IN AND RELATING TO FURNACE FRONTS, DOORS, DEAD
PLATES AND THEIR APPURTENANCES."
I construct my furnace front perforated towards the furnace, hollow, and arranged
so as to pass a constant current of air through it into the furnace, thus the front
is kept cool instead of radiating heat into the stokehole. The front is provided
with projecting cheeks or bearings in which the dead plate and door (all in one
piece like a bell crank) are pivotted.
They are free to revolve and are counterweighted so as to be in equilibrium
or nearly so. In stoking the door is pushed inward and takes the place of the
dead plate. In clearing out the clinker it is still further depressed, and leaves
a hole for the clinker to fall through, the dead plate and door acting as a screen
to keep the heat of the falling clinker from the stoker's legs and the stoke hole.
The door which of course is the same length as the dead plate, is preferably
hollow, perforated, and perpendicular next the furnace, the space between the two
parts being open to the entrance of air.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said Thomas Henderson in the Great Seal Patent Office on the 23rd
August 1880.
THOMAS HENDERSON, of 13, Harland Road, Higher Tranmere, in the County of
Chester. "IMPROVEMENTS IN AND RELATING TO FURNACE FRONTS, DOORS, DEAD!
PLATES, AND THEIR APPURTENANCES."
Fig. 1 is a front elevation of boiler showing my improved front and door, and
Figs. 2, 3, and 4, side elevation and transverse sections of the same showing the
door and dead plate in the positions when shut, when open for firing, and when
further opened for cleaning out the clinkers. A is the furnace front; B, perforations
in same for admission of air; C, chamber in furnaco front for the double purpose of
keeping the front cool, and for heating the air passing through it to the ashpit ;
D, back plate of furnace front perforated at bottom so as to admit air into tho
ashpit; E, cheeks on the furnace front; F, sockets or holes in same; G, fire door;
H, dead plate; these two are preferably cast in one, as shown; I, shaft upon which
G, H, is keyed or is carried, said shaft being supported in holes or sockets F;
J, spring of any description on axle I counterbalancing the tendency of the door
and dead plate to fall into position shown in Fig. 4; a balance weight could be
used instead of a spring if desirablo.
The door G, which is of the same length as the dead plate H, is provided with a s
perforated and perpendicular plate K next the furnace, the space between the two
parts being open for the entrance of air from below entering through aperturo L.
The manner of using is as follows:-Furnace with the door closed, as in Figs. 1
and 2, requiring charging. The fireman pushes the door with his shovel or with a
handle into position shown in Fig. 3; he then fires up, and when done changes the a
position of the door to what it was before. When cleaning out, however, he places
it as in Fig. 4; a space then nearer the grate than usual (that ordinarily occupied
by the dead plate) is left vacant, through which he can rake the clinker into the
ashpit, while at the same time the door and dead plate prevent radiated heat from
the incandescent clinker from entering the boiler room. The sulphur and other
gaseous matters with the hot air from the clinker pass up through the vacancy left
by the dead plate through the furnace into the chimney, without contaminating the
air of the stoke hole. The fireman in the mean time can stoke up again without.
the inconvenience of the radiation from the clinker and the sulphurous and other
fumes therefrom, which in the hitherto existing arrangements are so annoying.
The furnace front too is kept cool, the furnace supplied with heated air
above the bed, and the air drawn from the stoke hole, to the improvement of the
ventilation, by the arrangement of the air passages in the furnace front. The air
enters through the perforations B, circulates all over the front in the hollow
chamber between A and D, and heated by the passage through chamber C escapes 4
through perforations P, over or under the dead plate, or both over and under
according as door T is placed, as shown, or pointing up or down.
Having now described my Invention and the best mode known to me of carrying.
it into effect, I wish it to be understood that I ain well aware that perforated
furnace fronts and doors have been known and in use long before the date of my
Patent, and I do not therefore claim the broad principle of having an air circulating
space in the body of the furnace front or door, but that what I do claim to be new
and desire to protect under the hereinbefore in part recited Letters Patent is,-
First. The manufacture of furuaco apparatus in which the door and dead plate
revolve together, or turn in such manner that the door can act as a dead plate,
substantially as described.
Second. The manufacture of furnace apparatus in which the dead plate can be
lowered and caused to hang down when cleaning out, so that the clinker can be

page_text: drawn out into the ashpit instead of into the stoke hole, and the radiation and
gases from the clinker are prevented from escaping into the stoke hole by the said
hanging dead plate or its equivalent, substantially as described.
Third. The general arrangement of furnace front, substantially as herein
described and shown.
In witness whereof, I, the said Thomas Henderson, have hereunto set my
hand and seal, this Eighteenth day of August, in the year of our Lord One
thousand eight hundred and eighty.
Witness,
W. P. THOMPSON,
of the Patent Offices,
6, Lord Street, Liverpool,
& 323, High Holborn, London.
THOS. HENDERSON. (L.S.)