Furnaces for Steam Generators.
Year: 1896

page_text: Furnaces for Steam Generators.
I, THOMAS MURPHY, of 67 Alexandrine Avenue, West, in the City of Detroit,
County of Wayne and State of Michigan, United States of America, mechanical
engineer, do hereby declare the nature of this invention to be as follows:-
The invention relates to furnaces for steam generators and applicants improve-
ments apply more specifically to that type in which fuel magazines provided
with intermittently reciprocating coal pushers are located in the side walls of the
combustion chamber and which feed the coal at regular intervals in small
quantities at a time onto a V-shaped grate, supported in the longitudinal center
of the furnace by a grate bearer, which has an opening for the clinkers to drop
through into the ash pit, one or more toothed clinker bars being journaled in
the opening of the grate bearer for the purpose of crushing the clinkers by inter-
mittently rotating these clinker bars. The usual fire arch over the furnace with
air ducts in the corners is employed for furnishing hot air to mingle with the
gases, the coal before feeding it to the grates being subjected upon a so-called
coking plate which projects out in front of the magazine to a preliminary process
of coking.
One improvement consists in making the grate bearer of such a furnace hollow
and conducting steam, water or air into it for the purpose of keeping it cool, the
preferred way is to use exhaust steam from the engine and perforations are made
in the grate bearer for the escape of the steam against the underside of the hottest
part of the grate and especially into the space in which the clinkers collect,
whereby the latter are rendered brittle and are readily crushed and dropped into
the ash pit:
A further improvement consists of making the clinker bar hollow and intro-
ducing a cooling medium to prevent it from warping and burning out, preferably
a current of air is conducted through it and its bearings in the grate bearer
are so constructed that they cannot burn out so readily.
A further improvement consists in making the movable grate bars, which
alternate with the fixed grate bars in the usual way, of shorter length so that
wo or more independent tiers of movable grate bars are formed. The fixed
bars support the movable grate bars removably in position and at the same time
hey are free to expand and contract without danger of warping by abutting
heir inclined upper ends against a movable abutment or compensating plate
which is free to adjust itself vertically. The fixed grate bars for a portion of
heir length are provided with lateral flanges to prevent fine coal from falling
hrough.
A further improvement consists in actuating the several tiers independently
nd imparting to them a differential reciprocating motion so that the coal on
ts way from the magazine towards the center of the grate is gradually fed slower
a the same degree as it diminishes in bulk by being consumed and thereby the

page_text: coal is maintained evenly spread over the grate at all times and if the furnace
is of the kind in which the magazines are located in the side walls the movable
bars more in the rear of the furnace are given a gradually increasing feed motion,
so that the hotter part of the furnace in the rear which consumes more coal
receives a correspondingly increased amount and correspondingly therewith the
stokers or pushers supply a greater amount of fuel towards the rear.
The mechanical devices employed for operating the stoker and the movable parts
of the grate also permit a variable adjustment for increasing or diminishing
the feed in any desired ratio.
A further improvement applies to the fuel magazine and that part of it which
constitutes the coking surface, it consists in supporting it in a manner to keep it
out of contact with the heated brickwork of the furnace and passing a current
of air in contact with the parts most exposed to the heat.
THOMAS MURPHY.
Haseltine, Lake & Co.,
45 Southampton Buildings, London, W.C., Agents for the Applicant.
Improvements in Furnaces for Steam Generators.
I, THOMAS MURPHY, of 67 Alexandrine Avenue, West, in the City of Detroit,
County of Wayne and State of Michigan, United States of America, Mechanical
Engineer, do hereby declare the nature of this invention and in what manner
the same is to be performed, to be part.cularly described and ascertained in and
by the following statement: -
My invention relates more particularly to steam boilers and other furnaces of
the self-feeding, smokeless type, in which the grate bars are arranged either
in two rows on the opposite sides, or in front of the furnace chamber, and
inclined downwardly towards the center, or towards the rear, the fuel being
introduced at the top and fed down towards the middle or rear, in which there
is a device for mechanically removing the clinkers.
The object of my invention is to improve the mechanical devices for feeding
the fuel und removing the clinkers with a view to obtain greater efficiency and
further to safeguard against the destructive influence of the high heat which is
the most difficult factor to deal with in this class of furnaces, and to this end I
have devised an improved fuel feeding device including a new form of grate
which devices embody the new idea of feeding the fuel to each part of the furnace
exactly in the relative proportions to the degree of combustion which takes place
therein. Further, in the provisions which are made to lessen the liability of
damage to the parts exposed to the heat and to facilitate repairs where such
damage should occur. Further my invention comprises certain improvements
in the devices for removing the clinkers, all as more fully hereinafter described
and shown in the drawings, in which
Figure 1 is a cross section through a furnace embodying my improvements,
said furnace being represented as one of a battery of like furnaces.
Figure 2 is a vertical section on liner in Figure 1. Figure 3 is a sectional
perspective of a portion of the grate.
Figure 4 represents on a larger scale a portion of Figure 1. Figures 5, 6, 7
and 8 are detached perspective view of parts of the grate as indicated by the
letters of reference. Figure 9 is a horizontal section through the clinker bar
and its bearer. Figure 10 is a cross section thereof. Figure 11 is a front
elevation of the furnace.

page_text: In the said drawings, my improvements are shown in connection with a smoke-
less furnace, in which A represents a steam generator, B a combustion chamber,
C the fire arch of the combustion chamber, 1) is the fuel magazine located in
the sides of the combustion chamber and provided with discharge openings E
and supply chutes F.
G are coal pushers reciprocatingly actuated by the rock shafts H to feed tha
coal from the magazine into the grate.
I Figs. 2 and 11 is a reciprocating bar for imparting motion to the rock
shafts H, and J the air ducts for supplying heated air through narrow passages K
to the burning fuel upon the grate Fig. 1.
My improved grate forms the usual doubly inclined grate surface composed of
stationary grate bars L and alternate movable grate bars M. The movable grate
bars M are sectional bars, arranged in tiers, the drawings showing three tiers,
the bars on which alternate with the stationary bars so that one bar of each tier
moves in the spaces between two stationary bars.
b
These movable bars are supported in position by the stationary bars, and to
this end they are provided with laterally projecting lugs a which rest upon the
lugs 6 upon the sides of the stationary grate bars L see Figs. 4 5 and 8. Instead
of the lugs a b however, friction rollers c Figs. 1, 3, 4 and 5 secured in the
intervals between the stationary bars may be used to support the movable bars
upon.
In the drawings I show both means, as I preferably use them both, so that
while the rollers relieve the friction, the lugs prevent the possible tipping of
these bars.
Each movable grate bar is further supported in position by means of a rear-
wardly extending arm, terminating in a hook d, engaging with the swinging
bars which are suspended by means of links f. Each tier of movable grate
bars may be arranged in several independent groups, the bars of each group being
hooked upon separate swing bars c. The links which support these swing bars
are pivotally suspended from the stationary bars, by means of bars 9 and they
are provided with the sleeves i for the hooks d to engage upon.
The stationary grate bars are supported at their inner ends upon a grate
bearer N, which is composed of two hollow longitudinal bars united at distances.
apart by means of yokes O, and supporting in the space between them a clinker
bar Q, which rests upon removable bearing blocks 0 bolted in between under-
neath the yokes.
The grate bearer is formed hollow for the purpose of admitting steam or water
to it through the pipe leading in to it, and perforations are formed in the /
bearer for the steam to escape theretrom in small jets, upon both sides and.
between so as to envelop the exposed portions of the bearer, aud keep it cool,
and also to act upon the clinkers.
The clinker bar is of hollow tubular form, which is open ended, and its rear end
is connected with some point in the cross flues or chimney beyond the damper;
or simply discharges into a room, or into the open air at some point above the
clinker bar; the front end being open a continuous circulation of air will pass
through this clinker bar.
By having the discharge end above the level of the clinker bar, the heat in
the bar will produce circulation. By connecting it outside of the combustion
chamber or smoke flues of the furnace, the circulation is entirely independent of
the circulation through the furnace. The objection to having it connected into
the combustion chamber of the furnace is that the circulation through the clinker
bar would be shut off, if the furnace draft were shut off, and thus the circulation
reduced, while for a time the heat was increased.
The cliuker bar is provided on the outside with teats m which extend spirally
around the bar and the approximate inner edges of the bearers are provided
with similar teats m³ to aid in crushing the cinders when the clinker bar is
rocked, and also for preventing coal from falling through when starting the fire.

page_text: The stationary grate bars extend with their lower ends over the top of the
longitudinal bars of the grate bearer, and they are formed with hook shaped
bearings Fig. 10 which engage upon the top of said bearer to hold the grate
bars against longitudinal displacement, and lugs Fig. 3 cast in the bearer serve
to space the grate bars at fixed distances apart.
ין
The stationary grate bars are cast thin, and upon their sides along the upper
portion, they aro provided with short horizontal flanges arranged in the form
of steps, which, while permitting the free passage of the air between the grate
bars, intercept the fine fuel from falling through and thus adapt the grate to
the use of slack coal or culm. A few similar flanges may be provided along
the under edge of each grate bar to form, in connection with the flanges guides
to keep the movable grate bars in position between the stationary grate bars.
The upper end of the stationary grate bars abut against a wedge shaped com-
pensating plate R, Figs. 1, 4 and 7, which forms an inclined abutment to permit
the bars to expand more readily with the heat, and upon this abutment ribs n
are cast to serve as spacing lugs for the bars. This compensating plate is not
fastened in position so that it is free to move up and down with the expansion of
the grate bars.
The plate R is provided with a lip R' Figs. 4 and 7 which projects over the
top of the grate bars to prevent fuel falling between the grate bars and allowing
free passage of air to keep plate R cool, at the same time it forms a removable
part of the coking plate S.
The dead plate or coking plate S instead of being made in one piece, the whole
length, as heretofore, is made in sections, joined at the edges by lap tongue and
groove, and the compensating plate R is constructed in similar sections, and by
forming the coking plate sections with flanges S¹ I secure them to a supporting
beam by means of bolts 2, oblong openings in the plates R allow the latter to
movo up and down on the bolt heads.
Along the other edge the dead plate S Fig. 4 rests upon a cast iron bed plate U
to the underside of which is bolted the L-beam U, so arranged as to make in
connection with the L-beam T and the intermediate plate Us, an air chamber C
An air chamber U communicating therewith is formed at the rear end of the
magazine and leads into the air flue J from which it is fed through the passages K
into the furnace. As the front end of air chamber Us is open, a current of air
will be induced to flow through the air chambers U3 U, and keep the parts cool,
while, at the same time heated nir is introduced into the furnace.
The iron bed plate U is centrally slotted with the exception of the bearings u
which support the rook shaft thereon, the latter is provided with segmental
gears V, V and V2, which engage with corresponding segmental gears formed at
the ends of the vibrating levers W W and W The latter are pivotally secured
at their lower ends and are connected by rods Y Y and Y with a swing bar e
upon which the movable grate bars are hooked, all so arranged so as to impart a
horizontally reciprocating motion to the movable grate bars by the motion of
the rock shaft.
The swing barse of the corresponding groups in each tier of movable grate
bars are connected to the same pair of vibrating levers, and there are as many
pairs of levers as there are groups in each tier, but it will be seen, that the
amplitude of motion imparted to the groups connected to the same pair of levers
is not the same, as the rods Y are connected higher up on the levers than the
rods Y while the rods Y are connected below the rods Y', thus the groups of
grate bars actuated by the same pair of levers, have a differential feed. Provision
is also made to adjust the points of connections of the rods Y Y', Y2 with the
levers W, WW, higher or lower, for the purpose of adjusting the feed.
Furthermore I prefer to impart a differential movement to the vibrating levers
themselves, by making the segmental gears V V V of different radius, the
length of radius increasing from front to rear for each pair of levers, so that in
the rear the movable grate bars feed relatively faster than those in front.

page_text: In connection with this differential feed of the movable grate bars, there are
as many separate coal pushers provided as there are groups of movable grate
bars of each tier, and these coal pushers are differentially moved by means of
segmental gears Z Z 7 of different radii, increasing in length from front to rear.
There are two of these segmental gears attached to the rock shaft for each coal
pusher, and these engage with the racks formed on the under side of the coal
pushers, which have the form of a rectangular box open at the bottom. In this
manner, the movement of the rock shaft imparts a differential reciprocating
movement to the coal pushers, which feed the coal correspondingly faster, that
is in larger quantity, at the rear than in front corresponding to the differential
feed motion of the movable grate bars.
The parts being thus constructed and arranged as shown and described, they
are intended to operate as follows: The reciprocating bar I (the speed of which
can be regulated reciprocatingly) actuates the movable grate bars and the coal
pushers in a manier to feed the coal just in proportion to the proper require-
mments of the furnace, it being well known that the heat, and consequently the
combustion is more intense towards the rear of the furnace and by thus accommo-
dating the feed to the natural condition of things, the fuel is consumed with much
greater economy in the production of heat and in the better prevention of smoke
by maintaining an even thickness of coal over the grate surface. At the same
time, it will be seen that the fire may be regulated within much larger limits
as the varying requirements for steam may permit, thus the fuel fed may be cut
down to a lower limit without depriving any part of the grate of an adequate
supply of fuel to maintain a proper thickness and proper combustion, or the
furnace may be pushed to its highest duty, without coking the fire by feeding
too much coal in front, and at top of grate bars and thus producing smoke by
incomplete combustion. A differential feed based on the natural requirements
or capacity of the grate in different parts of the furnace is thus an important
improvement in self-feeding, smokoless furnaces.
While I have shown and described differentially movable groups of grate bars
in each tier, I claim equally as well a construction in which all the movable bars
in each tier are hooked upon a single swing bar extending from front to rear,
and in which the differential movement is brought about by imparting to the
rear end a larger movement than to the front end in the same manner as described
for differentially moving in groups.
It will be seen that the grate bearer is made hollow in the top portion, which
is most exposed to the heat; this allows the steam introduced therein to have
greater effect in keeping it cool, and at the same time the steam acts directly
upon the clinkers which accumulate there and which are rendered thereby brittle
and easily dislodged and removed by the cliuker crusher. Instead of steam,
water can be introduced in regulated quantities into the grate bearer, and con-
verted into steam by the heat of the bearer. By effecting the perfect crushing
and removal of the clinkers the effective grate surfaces are much increased, and
as the movable grates push the refuse directly upon the clinker bar, there is no
chance for the clinkers to form a bridge between the ends of the grate bars.
The clinker bar, which is so liable to warp and twist from the heat is effectively
cooled by having a current of cooling substance constantly passing through it,
and if it should need to be replaced, it can now be removed from the under side,
which is the most accessible part of the furnace. At the same time the yokes
being cast in one piece with the grate bearer the heat is conducted away from
them by the larger body of the bearer, and so the yokes which hold the clinker
bars in position are prevented from burning out while no cap or separate piece
could stand the heat."
The destructive effect of the heat upon the parts is further lessened by having
he coking plate S kept cool. by a circulation of air underneath it, and by dis-
ensing with all brick work underneath and in building a battery of boilers, I
neroly divide the furnaces off by a thin iron partition as shown in Figure 1
vhich partition may be bolted in between the hed plate U of the adjacent furnaces.

page_text: This gives ample space underneath the magazine and grates to have easy
access to ell parts (there being a convenient door in the furnace front) and the
construction is purposely devised to permit the renewal of any part from such
space. This is greatly facilitated by having the dead plate and other parts con-
structed in sections, aside from the econ ny it affords and it will be noted that
the bolts and other cont ections are removed from the influence of any direct heat
upon them.
The functions of the lateral flanges u₁ n the u per portions of the stationary
grate bars is also very important, as they virtually constitute a variable exten-
sion of the coking surface, thus as long as the fuel is merely coking, it will lodge
upon the flanges and prevent fine coal from falling through into the ash pit, but
as soon as the fuel is coked and catches fire, it will allow air to pass. These
flanges.hould not extend further down the bar than about one third of its 1 ugth,
so that the full supply of air can be passed freely between the bars for the remain-
ing two thirds of their length.
Having now particularly described and ascertained the nature of my said in-
vention, and in what manner the same is to be performed, I declare that what I
claim is:-
1. The improvements in furnaces substantially as herein described and shown
in the drawings.
2. In a furnace of the kind herein before described a rotary hollow clinker bar
and means for producing a constant circulation of air therethrough, independent
of the circulation of air through the furnace.
1007
HASELTINE, LAKE & Co.,
45 Southampton Buildings, W.C., Agents for the Applicant.