IMPROVEMENTS IN STEAM BOLLER AND OTHER FURNACES."
Year: 1879

page_text: PROVISIONAL SPECIFICATION left by Henry Clifton Carver at the Office of
the Commissioners of Patents on the 24th July 1879.
HENRY CLIFTON CARVER, of Llanidloes, in the County of Montgomery, Engineer*
"IMPROVEMENTS IN STEAM BOLLER AND OTHER FURNACES."
My improvements in steam boiler and other furnaces have reference to the con-
struction of the fire grates of such furnaces, and means for causing some of the bars
to act upon the fuel so as to break up or prevent formation of clinker, and to move
the fuel intermittently from the furnace front towards the bridge. For those
purposes I employ transverse stationary fire bars constructed with wings or
projections in conjunction with tipping bars formed with wings or projections
entering between the wings or projections of the stationary bars. I
arrange the
tipping bars to work on rods or pins in such a manner as to break up and raise the
fuel across (it may be throughout the width of) the grate by an upward movement
of the main portion of each tipping bar, which I form as the arc of a circle struck
from the centre on which the bar moves, so as to prevent fuel falling between the
bars. Between the fixed dead plate and the front of the grate I interpose a tilting
dead plate formed with a curved part similar to that already described with
reference to the bars, to prevent fuel falling between the fixed dead plate and the
tilting one. I provide each tipping bar with a crank, and I actuate the said bars
by rods operated by means of levers or hooks arranged on a supporting shaft having
vibrating and rotary motions imparted to it in such manner as to cause the tipping
bars to be tilted successively. One mode of effecting this is as follows:-To the
crank of each tipping bar I connect an actuating rod, one end of which I provide
with a suitable handle so that the bars may be operated manually if desired, and
thus any one section of the fire may be agitated without disturbing the remainder.
A convenient mode of connection between each rod and its bar is by a crank pin
having an eccentric shoulder, and passing through a slotted hole in the eye of the
rod, so that the connection may be made and unmade by an operator placed at the
front of the ash pit or furnace flue, even while the furnace is under fire. Each
actuating rod is formed with a segmental part which rests upon a shaft to which
vibrating and rotative motions are imparted as hereinafter described, the segmental
portion of the actuating rod serving to prevent that rod having an up and down
motion imparted to it by the vibration of the supporting shaft. The supporting
shaft is carried and vibrated by levers or arms secured upon a shaft to which
oscillatory movement is imparted from any suitable source; it may be from the

page_text: worm wheel of a mechanical stoker, or some equivalent contrivance. The rotation
of the vibrating supporting shaft is produced by the action of two pawls upon one
of two ratchet wheels (I will call them for distinction A and B respectively) which
is held fast upon the said shaft, upon which also are arranged a number of hook like
levers or lifters, hereinafter called hooks, one to each actuating rod, the vibrating
supporting shaft rotating freely within the eyes of the said hooks except when (in
one arrangement) certain projections on the vibrating supporting shaft come in
contact with springs carried by the hooks. When this occurs the ends of the hooks
are pressed upwards, so as to enter recesses in the under sides of the actuating rods
of the tipping bars. These rods prevent the hooks from being rotated with the
vibrating supporting shaft, and as its rotation continues the projections slip past
the points of the hook springs, and the hooked ends of the hooks drop down upon
a supporting bar, and become disengaged from the actuating rods. The projections
on the vibrating supporting shaft are so arranged that only one hook is made to
engage at a time with its corresponding fire bar actuating rod, and that the hook
shall remain engaged during only one complete double vibration of the vibrating
supporting shaft at one time. The motion thus given to the actuating rods is
imparted to the tipping bars, so as to move them in the manner herein before
referred to. The hook supporting bar is carried by two pendulums which are made
to vibrate by connecting links, which take on to the vibrating supporting shaft,
and to pins on the said pendulums; one or both of these links may be formed so as
to act as a friction brake upon the vibrating supporting shaft in order to prevent
it from rotating at improper times, or a separate friction brake may be provided.
One of the two pawls herein before referred to, and which I will for distinction
call C, hinges upon a pin secured to one of the levers or arms carrying the vibrating
supporting shaft, and the other of the two pawls (which I will call D) is hinged
upon the pin of one of the pendulums. Upon the same pin is a third pawl (I will
call E) which actuates the second ratchet wheel B, which is situate alongside the
ratchet wheel A upon an axis on a lover which vibrates coincidentally with the
levers or arms carrying the vibrating supporting shaft. On one side of the ratchet
wheel B are two circular paths, each path being notched once; the point of each of
the pawls C, D, is wide enough to rest upon one of these paths as well as upon the
ratchet wheel A, the arrangement being such that when they rest upon the paths they
do not engage with the ratchet wheel A, but that when the points of the pawls are
opposite the notches in the circular paths of the ratchet wheel B (which they both
are at one and the same time) the pawls drop into engagement with the ratchet
wheel A. In the ratchet wheel B a few teeth are omitted at one part of the
periphery, so that when the pawl E is vibrating over this part it produces no
rotation in the ratchet wheel B. Both ratchet wheels and the rotating supporting
shaft rotate in the same direction. Upon the ratchet wheel A is an abutment, and
upon the ratchet wheel B there is also an abutment, one of the abutments being
made to yield so that B cannot push A, but so as not to prevent A from pushing B.
The abutment on A overtakes and comes in contact with B at intervals as herein-
after described, but cannot pass by it. Supposing the position of the parts to be
such that the pawls C, D, are in their respective notches in the paths of the ratchet
wheel B, and are engaged with the ratchet wheel A. while the pawl E is disengaged
from the ratchet wheel B, owing to the position occupied by the toothless portion
of its periphery. As the rotation of the ratchet wheel A proceeds its abutment
comes in contact with the abutment of the ratchet wheel B, and pushes that ratchet
wheel partially round on its axis so as to lift the pawls C, D, on to the two circular
paths of the ratchet wheel B, and so as to bring the teeth of this ratchet wheel
under the influence of the pawl E, which continues to rotate it while the ratchet
wheel A remains stationary on its axis until the notches in the paths of the ratchet
wheel B again come into position opposite the pawls C, D, and the toothless portion
comes opposite the pawl E. While the ratchet wheel A is being rotated each of the
tipping bars one after the other, and commencing with the one nearest to the fire
bridge makes one complete double oscillation owing to each of the respective actuating

page_text: rods having become engaged by the hooks as before mentioned. While the ratchet
wheel B is rotating and the ratchet wheel A remains stationary upon its axis, the
tipping bars are all at rest. The duration of this period of rest is regulated by
means of a segmental plate concentric with the ratchet wheel B, which can be
adjusted so as to cause the pawl E to advance the ratchet wheel by one or more
teeth at each vibration as may be desired.
A rod connected at one end of the lever upon the oscillating portion of the dead
plate and at the other end to the vibrating supporting shaft causes an oscillation of
this part of the dead plate at each vibration of that shaft; by this means the
oscillating dead plate is kept sufficiently free from any deposit of fuel. In another
arrangement for causing the engagement and release of the hooks in reference to
the actuating rods of the tipping bars, the vibrating supporting shaft is caused to
intermittently rotate by means of an arrangement of ratchet wheels and pawls as
already described, and is provided with recesses in lieu of projections. The hooks
are provided with heels which may be fitted with set screws for purposes of
adjustment. The actuating rods of the tipping bars are formed with a sort of
shoulder so as to allow them to drop slightly when the recesses of the vibrating
supporting shaft come under these shoulders. When this slight drop occurs, the
actuating rods depress the heels of the hooks by coming in contact with them or
with the set screws with which they may be fitted, and cause the hooks to engage
with the actuating rods. As no recess of the vibrating supporting shaft remains in
position under the shoulder of an actuating rod during more than one vibration of
the said supporting shaft, and as in any other position the drop of the corresponding
actuating rod does not occur, it follows that each actuating rod remains engaged
during only one vibration of the supporting shaft at a time, the weight of the hooks
being sufficient to disengage them at the end of the stroke unless they are forcibly
kept up.
One side of each engaging recess in the actuating rods is made deep in order that
the hooks whether in their lifted or in their dropped position may force back the
actuating rods to their normal position of rest.
The ratchet wheel B is made to rotate stiffly upon its axis by means of a friction
plate or similar contrivance in order to prevent it from being readily rotated by a
touch at improper times, or a second pawl may be made to act upon it to prevent
this. On the other hand one of the pawls to the ratchet wheel A may be dispensed
with, as a friction brake referred to will suffice to prevent improper rotation.