IMPROVEMENTS IN FURNACES AND FIRE-PLACES
Year: 1848

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
GRIST, of the New North Road, in the County of Middlesex, Engineer, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent under the Great Seal of the United Kingdom of Great
Britain and Ireland, bearing date at Westminster, the Twenty-ninth day of
July, One thousand eight hundred and forty-eight, in the twelfth year of Her
reign, did, for Herself, Her heirs and successors, give and grant unto me, the
said John Grist, my exors, adñiors, and assigns, Her especial licence, full
power, sole privilege and authority, that I, the said John Grist, my exors,
adñiors, and assigns, and such others as I, the said John Grist, my exors,
adiors, or assigns, should at any time agree with, and no others, from time
to time and at all times during the term of years therein expressed, should
and lawfully might make, use, exercise, and vend, within England, Wales,
and the Town of Berwick upon Tweed, and in the Islands of Jersey, Guernsey,
Alderney, Sark, and Man, and in all Her said Majesty's Colonies and Planta-
tions abroad, my Invention of "IMPROVEMENTS IN FURNACES AND FIRE-PLACES;"
in which said Letters Patent is contained a proviso that I, the said John
Grist, should cause a particular description of the nature of my said Invention,
and the manner in which the same is to be performed, by an instrument in
writing under my hand and seal, to be inrolled in Her said Majesty's High Court
of Chancery within six calendar months next and immediately after the date
of the said in part recited Letters Patent, as in and by the saine, reference
being thereunto had, will more fully and at large appear.

page_text: NOW KNOW YE, that in compliance with the said proviso, 1, the said
John Grist, hereby declare that the nature of my said Invention, and in
what manner the same is to be performed, are fully described and ascertained
in and by the present Specification thereof, that is to say:-
Firstly, my Invention consists in an improved arrangement of means for
adjusting with exactness the feed of fuel to furnaces to their consumption, for
giving a progressive movement to the fuel in the furnace while in the course of
being consumed, and for making parts of the furnace serve as additional water
spaces to the boiler.
Figure 1 is a top plan of a furnace embodying this improved arrangement
with the boiler removed. Figure 2 is a longitudinal section on the line a, b, of
Figure 1 and Figure 3 is a front elevation. A, A, are two side frames con-
nected together by transverse stay bolts B, B, B; C, C, are continuous grooves
or channels formed on the inner faces of the side frames A, A; D, D, fire bars,
which rest and move forwards and backwards in the grooves C, C, when acted
upon, as herein-after explained. E and E' are two spindles or shafts, which
fit concentrically into the semicircular ends of the grooves C, C, at the front
and back ends of the furnace. Each of these shafts again carries two discs or
wheels F, F, F, F', the peripheries of which coincide with and form in effect
the inner sides of the grooves C, C. G is a toothed wheel, which is keyed to
the same shaft E as the discs E, F, so that when that wheel is made to rotate
it carries the discs F, F, along with it. H is the hopper, which has a move-
able front L; J, the opening from the hopper to the interior of the furnace;
M, the fire door; P, the handle; N and O, toothed segments and racks by
which the door is raised and lowered; and K, the boiler. The atmospheric
air, it will be seen, has a free and uimpeded passage into the heart of the fur-
The fire bars, instead of being cast singly, are cast in sets of fours, as
separately represented on an enlarged scale in Figure 4, which is a top plan,
and in Figure 5, an edge or side view, of a single bar or set of bars. The object
in having the bars cast in sets is to produce greater steadiness of motion in
passing along the grooves, and to prevent their getting into an angular position
and falling out of the grooves.
nace.
The mode of working this furnace is as follows:-The moveable front L of
the hopper is taken out, and the fire door M lifted up by means of the toothed
segments N and racks O. The attendant has then access to the furnace to
kindle the fire, after which he adjusts the door to the proper height to give the
requisite feed of coal to the furnace. The front of the hopper being replaced,
it is filled with fuel. Motion is then communicated to the wheel G by hand,
which causes the whole of the uppermost set of fire bars (which only are for

page_text: the moment covered with fuel) to advance gradually from the front of the fur-
nace towards the back end of it. The fire bars so pushed forwards press
against the bars resting upon the dises F, F, and in the lower groove C, C,
and thereby cause them to advance from the back towards the front of the
furnace, that is to say, the teeth R, R, or R', R', affixed to the discs F, F, (one
or other of them pressing upon the bar next in the series) cause a simultaneous
progression of the furnace bars from front to back and from back to front.
The movement just described causes in the first instance the bars which
were under the hopper to carry into the mouth of the furnace a certain
quantity of coal, where it is coked, while at the same time the whole of the
fire resting upon the upper surface of the fire bars at top is made to pass a
short distance towards the back of the furnace. The moment the teeth R, R,
have thus pushed the bars as far forward as will allow of their passing clear,
then the bars, fire, &c. remain unaltered by the rotation of the discs F, F,
until the single set of four bars D', which are in advance of the teeth R¹, R¹,
are by the rotation of the discs F, F, brought up so as to press against the
last bar which was acted upon by the teeth R, R, when another portion of
fresh coal is introduced into the furnace, and that which had just previously
been supplied having had time to become coked, is carried further into the
furnace, and so the action goes on as long as motion is communicated to the
wheel G and fuel supplied to the hopper. The rate of feed is of course regu-
lated by the height the door M is raised up from the surface of the fire bars
and the degree of velocity given to the wheel G; motion may be given to the
wheel G either by hand or by means of wheel gearing driven by any prime
mover. To work this furnace to the greatest advantage the opening for the
supply of fuel and the motion of the bars should be so adjusted in respect of
cach other that the whole of the supply of coal or fuel should be nearly burnt
off the bars before passing under the bridge S of the furnace. T is a pinion,
which gears into the wheel G, and is fixed upon the end of a shaft U, which
carries two pulleys V, V. The office of these pulleys is to cause the last of the
bars in the lower groove C to be carried sufficiently far forward to be laid hold
of by the teeth R, R, or R', R', and so to prevent the bars resting in such a
position as to get interlocked between the teeth, as in stirring up the fire by
means of irons introduced through the furnace door the bars would be liable
(if not secured in the meanwhile) to get pushed out of their places; this is
prevented by means of a bent lever W, which is acted upon by the handle W',
so that when that handle is raised up, the opposite ends of the lever W take
into the furnace bars and prevents their moving for the time being, either for-
wards or backwards.

page_text: Sometimes, instead. of having the bridge of this furnace solid,. I make it.
hollow and of the same sort of materials as the boiler itself, and connect it to
the boiler by means of sets of pipes X and X', as represented in Figure 2,
one set of which are continued some distance up inside the boiler and serve to
carry off the steam generated in the bridge.
In the event of any of the bars becoming wasted or broken, they can easily
be taken out and replaced. even while the furnace is in action, by opening a
portion Y of the front side of the grooves C, C, this part of the ledge of the
groove being hinged so that it readily admits of being opened for this purpose.
Z is one of a pair of levers, which are affixed one to each side frame by the
pin, upon which they are free to turn as on an axis. These levers produce a
dragging effect upon the bars D, D, on which they rest, and so prevent them.
from being pushed forward by the weight of those bars which are in the semi-
circular portion of the groove. C, C, at the back end of the furnace. The.
levers Zare pressed, down by a weight 22, which lays across the ends of both.
levers..
When furnaces of this description are constructed of large dimensions, or
when the furnace bars are likely to be subjected to a very high degree of tem-
perature, then in order to reduce the friction produced by the rubbing of the
fire bars in travelling along the grooves C, C, I introduce a set of friction
wheels A, A, which are mounted, as represented in Figure 5, in proper bear-
ings formed in the lower sides of the continuous groove C, C, and placed at
about distances of nine or ten inches apart. The distance between the one
friction wheel to the other is made always less than the breadth of one of the.
combined sets of bars, so that the bars may at no time be left entirely resting
the lip or side of the groove.. By this arrangement the movement of the..
bars is greatly facilitated and less power required to work the furnace. Again,.
to prevent the bars from falling down or bending under the weight of the fuel
when they become heated, I pass a beam or bar D (or two or more such bars)
nearly the whole length of the furnace under the the fire bars. The upper
edge of this beam is also provided with friction wheels, and the fire bars them-
selves have a central rib by which they may rest and run upon the friction
wheels. The central bar 13 is supported by angular struts E, E, from the side
frames of the furnace.
upon,
Figure 6 is a sectional elevation of another arrangement for supplying a
regular feed of fuel from the hopper into the furnace; A is the furnace; B,
the dead or coking plate; C, the hopper; D, a drum, which is divided into
four longitudinal compartments (the compartments may be of any other con-
venient number). A regular motion is given to this drum by any system of

page_text: wheel gearing connected to a prime mover. The uppermost compartment
gets filled with coal from the hopper, and in the course of the revolution of
the drum it empties its contents upon the coking plate while the next of the
compartments in succession is being filled from the hopper, and thus a constant
supply of fuel is kept up to the fire. To make the heat of the furnace as
available as may be I form the two dises F', F', into a hollow cylinder or drum
by the addition of an intervening tube of the same diameter, and connect this
drum by pipes with the boiler and the pump by which the boiler is fed.
The red lines in Figures 1, 2, and 3, shew another method of causing the
fire bars when they come out of action in the furnace and have descended to
the lower portion of the continuous groove C, C, to moved towards the front of
the furnace, and whereby also all the fire bars in the lower part of the con-
tinuous groove from d to c may be dispensed with. A, A³, are two links,
which rest upon excentric pinions B', B³, and are furnished with teeth upon
only one third of their peripheries, which teeth alternately gear into cor-
responding teeth formed in the upper and under sides and inside of the
links A³, A³, and cause them to have a rectilinear motion alternately from
front to back and from back to front of the furnace, and at the termination
of each of those movements to be either raised up or lowered down, so that
when motion is given to these excentric pinions, they revolve in the course
indicated by the arrows. The teeth C, C, which are on the under side of the
links, cause the bar at d to travel towards the front of the furnace; then the
next revolution of the pinions and the next of the teeth C³ in advance cause
a similar advance of the bar, and so the action goes on until the bar is brought
under the teeth R, R, of the discs F, F. Motion is given to the excentric
pinions by bevil gear attached to the shaft E.
Secondly, my said Invention has relation to the furnaces of locomotive
engines, and consists in the improvements represented in the longitudinal
section of a locomotive engine fire box, given in Figure 7. A is the fire box;
B, B, the water spaces; C, the cylindrical part of the boiler; D, one of the
fire bars, which I make of hollow tubes of metal, of sufficient strength to resist
the pressure which the boiler is supposed to be able to sustain. These fire
bars are inclined at an angle from the horizontal line, and have free commu-
nication at both ends with the water spaces of the boiler. By thus having the
hollow fire bars placed inclining at an angle to the horizontal line, as repre-
sented, a free circulation of water is kept up within them, and there is no
danger of the water being entirely driven out of them by the generation of
steam, as almost always occurs in the case of horizontal water fire bars. E is
the furnace door, through which the fuel is supplied; and F, a door for with-

page_text: drawing the fire from the furnace when necessary. The door F is furnished
on the inside with a "lump" or fire brick, to prevent its being destroyed by
the interior heat.
1
**Figure 8 represents another improved method of connecting inclined hollow
fire bars with the water spaces of the boilers of locomotive engines. The
Figure is a cross section of a locomotive engine fire boxe, so that in this
arrangement the bars are laid across the fire box, while in Figure 7 they are
represented as being laid longitudinally. A, A, is the furnace; B, B, the
water spaces; C, a longitudinal chamber, to which the water bars E, E, are
connected, and which is connected with the crown of the fire box by a pipe or
a series of pipes D, which carries off to the bolier the steam generated in the
chamber C and the fire bars E, E, and by which also the circulation of water
is kept up through the interior of the bars and chamber.
Lastly, my Invention consists in an improvement in the fire-places of ovens,
represented in the sectional plan of an oven and furnace given in Figure 9,
whereby the heat is encreased and smoke prevented. A, A, is the oven; B,
the door; C, the fire-place; D, D, are two side flues, which are opened and
closed by dampers a, a, so that the supply of atmospheric air to the further
end of the furnace can be adjusted at pleasure.
And having now described the nature of my said Invention, and in what
manner the same is to be performed, I declare that the improvements which I
claim as constituting my said Invention, are as follows:-First, I claim the
improved arrangement of means for adjusting with exactness the feed to the
consumption of fuel and furnaces, and for giving a progressive movement to
the fuel while in the course of being consumed embodied in the furnace first
herein-before described, that is to say, in so far as regards the wheel G and
the parts connected therewith, whereby they regulate simultaneously the
delivery of fuel from the hopper and the progression of the fire bars without
impeding the free course of the atmospheric air into the heart of the furnace;
and in so far also as regards the employment of loose fire bars running singly
.or in sets of three or four in grooves; the hinged side flap for withdrawing
aud replacing the bars when worn out, and the application thereto of an under
supporting bar or bars and friction wheels. Second, I claim the employment
in boiler furnaces of hollow bridges, when connected by two sets of pipes with
the water spaces in the boiler, as before described; and the formation of the
furnace discs F', F', into a drum, communicating with the boiler and feed
pump, as before described. Third, I claim the alternative mode of regulating
the delivery of fuel from the hopper represented in Figure 6, and before
described. Fourth, I claim the alternative mode of giving progressive motion