Improvements in Supplying Atmospheric Air to Furnaces through Tubular Grate Bars.
Year: 1892

page_text: Date of Application, 9th May, 1892
Complete Specification Left, 8th Feb., 1893-Accepted, 11th Mar., 1893
PROVISIONAL SPECIFICATION.
Improvements in Supplying Atmospheric Air to Furnaces through
Tubular Grate Bars.
I, SAMUEL OATES, of 45 Kearsley Road, Sheffield, in the County of York,
Engineer, do hereby declare the nature of this invention to be as follows:-
The object of this invention is to improve the means of controlling currents of
atmospheric air which are induced through tubular or hollow grate bars, used in
boiler and other furnaces for the purpose of conveying them to the bridges with a
view of their meeting and combining with the escaping incombustible gases, and
converting them into combustible compounds and subsequent smokeless flame.
It is well known to those who have used tubular or hollow grate bars, that in
heavily fired boilers, or where a great quantity of fuel is necessarily consumed, it is
impossible to pass a sufficient quantity of air through them to convert all the
escaping gases into combustible compounds, with the draught due to the ordinary
chimney power, especially when fresh fuel has been added to the fires, or when they
have just been broken up with the rake or poker; consequently those unconverted
gases pass off into the flues and chimney unconsumed, forming dense volumes of
smoke, and become both a nuisance and a direct loss.
"
In order to remedy this defect, I connect a "pipe" to the steam space of a boiler,
or other suitable place from whence a supply of steam can be obtained and continue
it across the front end of the grate bars, but not touching them, and opposite to, or
in front of, the open end of each tube or grate bar, I fix in this " pipe a small
branch pipe, or nozzle, to enable me to pass a small jet of steam into the hollow
channel or tube of each bar for the purpose of inducing a stronger current of air
to pass through them than would otherwise do with the ordinary chimney draught
for the above mentioned purpose; but as it is only necessary to do this when extra
amount of gases are being evolved, such as will take place immediately after adding
fresh fuel, or in breaking up the fires in the grates, I arrange to shut off the flow of
steam to the jets when it is not required, this I do automatically, and I proceed in
the following manner :-
66
In any convenient position I fix in the pipe above referred to, a cock or
equilibrium turn-valve, which is connected by rods, levers and shafts to a
"
cataract" or it can be connected to any other of the well known controlling
apparatus now in use, but in any or either case, I cause the opening of the steam
turn-valve to be done quickly, and the closing of same to be done slowly, and in any
desired period of time.
To insure this controlling apparatus being put into operation when it is required,
I make a connection by rods, levers, &c., between a sliding damper which slides up
and down between the fire hole door and the furnace front, or to the fire hole door
itself, and the above mentioned controlling apparatus, so that when the fireman
opens the door, or lifts the sliding damper for the purpose of adding fuel to the fires,
or in any way interfering with them, he must actuate the "turn-valve" to enable a
flow of steam to pass through the "jets" into the channel of the tubular bars,
thus inducing a current of air through them, and when he has closed the fire hole
door the return motion of the controlling apparatus will cause the steam "turn-
valve" to revolve in the opposite direction and shut off the connection between the
source of the steam supply and the jets, slowly and gradually according to the
speed considered necessary, thus shutting off the inducing medium as desired.
When I wish to completely arrest the flow of air through the tubulous bars to
the bridge, I fix a valve or flappet on a rocking shaft near to the outlet end of the
bars, and by means of rods and levers I connect this valve or flappet to the

page_text: controlling apparatus, thereby opening and closing the outlet simultaneously with
the opening and closing of the steam jets.
It will now be easily seen that whenever the fireman interferes in any way with
the fires, on the grate, he must make provision for inducing an increased current of
air through the bars to meet the increased quantity of gases generated, and that
the inducing medium of such an increased current of air can be controlled and
slowly shut off by means of a cataract or other controlling mechanism.
"
"
The passing of these intermittent increased currents of air through the bars
assists very materially in keeping them cool, consequently prolongs. their life or
indurance and prevents the channels of the tubes becoming blocked up with small
ashes and dust.
Dated this 9th day of May 1802
CARPMAEL & Co.,
Agents for the Applicant.
;
1
COMPLETE SPECIFICATION.
Improvements in Supplying Atmospheric Air to Furnaces through
Tubular Grate Bars.
I, SAMUEL OATES of 45 Kearsley Road, Sheffield, in the County of York,
Engineer, do hereby declare the nature of this invention and in what manner the
same is to be performed to be particularly described and ascertained in and by the
following statement
The object of this invention is to improve the means of controlling currents of
atmospheric air which are induced through tubular or hollow grate bars, used in
boiler and other furnaces, for the purpose of conveying them to the bridges with a
view of their meeting and combining with the escaping incombustible gases, and
converting them into combustible compounds and subsequent smokeless flame.
It is well known to those who have used tubular or hollow grate bars, that in
heavily fired boilers, or where a great quantity of fuel is necessarily consumed, it
is impossible to pass a sufficient quantity of air through them to convert all the
escaping gases into combustible compounds, with the draught due to the ordinary
chimney power, especially when fresh fuel has been added to the fires, or when
they have just been broken up with the rake or poker, consequently those uncon-
verted gases pass off. into the flues and chimney unconsumed, forming dense
volumes of smoke, and become both a nuisance and a direct loss..
6
.
In order to remedy this defect, I connect a "pipe", to the steam space of a
boiler, or other suitable place from whence a supply of steam can be obtained and
continue it across the front end of the grate bars, but not touching them, and
opposite to, or in front of, the open end of each tube or grate bar. I fix in this
pipe" a small branch pipe, or nozzle, to enable me to pass a small jet of steam
into the hollow channel or tube of each bar for the purpose of inducing a stronger
current of air to pass through them than would otherwise do with the ordinary
chimney draught for the above mentioned purpose, but as it is only necessary to
do this when extra amount of gases are being evolved, such as will take place
immediately after adding fresh fuel, or in breaking up the fires in the grates.. I
arrange to shut off the flow of steam to the jets when it is not required, this I do
automatically and I proceed in the following manner:
In any convenient position I fix in the pipe above referred to, a cock or equi-
librium turn-valve, which is connected by rods, levers and shafts to a "cataract."
or it can be connected to any other of the well known controlling apparatus now in
use, but in any or either case, I cause the opening of the steam turn valve to be
done quickly and the closing of same to be done slowly, and in any desired period
of time.
To insure this controlling apparatus being put into operation when it is required,
I make a connection by rods, levers, &c. between a sliding dainper which slides up

page_text: and down between the fire hole door and the furnace front, or to the fire hole door
itself, and the above mentioned controlling apparatus, so that when the fireman
opens the door, or lifts the sliding damper for the purpose of adding fuel to the
fires, or in anyway interfering with them, he must actuate the "turn-valve" to
enable a flow of steam to pass through the "jets" into the channel of the
tubular bars, thus inducing a current of air through them, and when he has closed
the. fire hole door the return motion of the controlling apparatus will cause the
steam "turn-valve" to revolve in the opposite direction and shut off the connection
between the source of the steam supply and the jets, slowly and gradually
according to the speed considered necessary; thus shutting off the inducing medium
as desired.
When I wish to completely arrest the flow of air through the tubular, bars to the
bridge I fix a valve or flappet on a rocking shaft near to the outlet end of the
bars, and by means of rods and levers I connect this valve or flappet to
the controlling apparatus, thereby opening and closing the outlet simultaneously
with the opening and closing of the steam jets.
>
It will now be easily seen that whenever the fireman interferes in anyway with
the fires on the grate, he must make provision for inducing an increased current of
air through the bars to meet the increased quantity of gases generated, and that
the inducing medium of such an increased current of air can be controlled and
slowly shut off by means of a "cataract or other controlling mechanism.
"
The passing of these intermittent increased currents of air through the bars
assists very materially in keeping them cool, consequently prolongs their life or
endurance and prevents the channels of the tubes becoming blocked up with small
ashes and dust.
There are various ways of carrying out my invention.
Figures 1 and 2 shew one arrangement of my apparatus applied to an ordinary
Lancashire or double flued boiler.
Figure 1 is an elevation of the apparatus at the front end of the boiler.
Figure 2 is a side elevation and part section of same, it also shows a part
longitudinal section of the boiler shell and one of the furnace tubes.
Figures 3 and 4 show another arrangement of my apparatus applied to an
ordinary Cornish or single flued boiler.
Figure 3 shows a front elevation of my apparatus, and the boiler end.
Figure 4 is a side elevation of my apparatus, it also shows the boiler in part
side elevation and part sectional elevation, the furnace tube and bridge being also
in sectional elevation.
Figures 5 and 6 show in detail one arrangement of cataract or controlling
apparatus that I sometimes employ. Figure 5 being a side elevation of the same
showing a portion of the cylinder, piston, valve, and water passages in section.
Figure 6 is a plan of the same with the top cover of the cylinder and lever
removed.
When I wish that my apparatus shall be put in operation simultaneously with
the raising of a slide or damper that works vertically between the firehole door
and the boiler front, I arrange it as shown by Figures 1 and 2 in which A is
the sliding damper, it is actuated in the manner described in my Specification
No. 5018; B is the firehole door, C is the lower shaft or axis which is carried
in brackets A that are suspended from the door or damper frame A'. This shaft
is actuated by the handing lever D, and is connected to the lever E' of the
controlling cataract cylinder E by means of an arm C¹ and a rod C³, it is also
connected to the upper shaft or axis F by means of an arm C³, the rod C and
the arm F. This upper shaft F is carried in brackets A³ that are also connected
to the frame A'; on this shaft is another arm F which is connected to the upper
end of a rod F, the lower end of this rod being connected to an arm G' that is
securely fastened to the spindle of the steam cock or turn valve G. This valve
is fixed in a range of steam pipes G' through which the steam flows from its source
of supply into the pipes G that extend across the furnace tubes in front of.the

page_text: '
hollow grate bars H which may be of any usual form. From the pipes G³ project
a number of branch pipes or nozzles G₁ that convey a small jet of steam into the
end of each hollow or tubular grate bar, thus inducing a current of air through
the grate bars into the opening behind the bridge I. On the shaft C is also
another arm C that is connected to the flap valve I by means of a rod 12 and the
arm I, this arm and the flap valve I' being secured to the shaft or axis I carried
in brackets 13 which are fixed to the bridge plate 1°. A small door 1' is
hung from this plate, and is used for cleaning out any fuel or ashes that may
have dropped over the bridge I.
The apparatus is shown with the sliding damper A, the handing lever D, and
the piston in the controlling cylinder E in their highest positions: they have been
lifted there by the fireman, in order to allow of his access to the fire on the grate
bars. In performing this operation he must cause the axis F to turn and bring
the arms F and G' into a corresponding position, which will so actuate the plug
of the steam valve G, that it opens the communication between the pipes G
and G3 thus allowing steam to flow from its source of supply to the nozzles G
and (the flap valve I¹ being open) thence forward into the channels or tubes of the
grate bars H inducing a current of air to pass through them into the opening
behind the bridge I, and through the outlet I thus mixing and combining with the
incombustible gases as they pass over the bridge.
The slide or damper A after it has been raised descends slowly, being controlled
by the cataract E; and simultaneously with this descending of the damper A, the
plug of the steam valve. G turns in its outer casing and gradually closes the com-
munication between the source of the steam supply and the nozzles G. At the
same time the flap valve I will also be caused to gradually close against the outlet
ends of the grate bars thus arresting totally, or nearly so, any flow of air through
them into the opening of the bridge 1.
When I wish that my apparatus shall be put into operation simultaneously with
the opening of the firehole door, I sometimes arrange it as shewn by Figures 3
and 4 which may be described as follows:-
-
When the fireman wishes to add fuel to the fire, or in anyway interfere with it,
he must necessarily open the firehole door B, which turns in the hinge B2, in doing
this the pin B3 having a square shoulder formed under its bead is caused to turn
and make a part of a revolution corresponding with the angular movement of the
firehole door. On the lower end of this pin is securely fixed an arm B which
turns with the pin B³; during this turning the arm B' presses with a sliding contact
on the arm C¹ keyed or otherwise fastened on the shaft or axis C. Therefore,
when the door B is being opened the arm B causes the axis C to turn in the
brackets A². On this axis is also fixed another arm Cx which is connected to the
lower end of a rod C' the upper end of this rod being connected to the lever E' of
the cataract. On the axis is another arm F which is connected to the lower
end of a rod F, the upper end of which is connected to an arm G' that is securely
fastened to the spindle of the steam cock or turn valve G. The valve G is fixed in
a range of pipes G' and G³ which are similar in form and purpose to those already
described and illustrated in respect to Figures 1 and 2.
Therefore, it will now be easily seen, that simultaneously with the raising of the
sliding damper A Figures 1 and 2 or the opening of the firehole door B Figures 3
and 4 the steam turn valve G is caused to open and allow a volume of steam to
flow from the source of its supply through the pipes G2 and G³ into the channels of
hollow grate bars, for the purpose of inducing currents of air through them, to or
behind, the bridge I as in Figures 1 and 2 or into the bridge box I and thence
through the outlets 18 as in Figures 3 and 4 where the currents meet and mix with
the gases that are passing over the bridge unconsumed. It will also be seen that
simultaneously with the controlled descent of the ram or piston in the cataract
cylinder E, the steam turn valve G will slowly and gradually close, and shut off
the inducing medium as before described. In Figures 3 and 4 the levers are shewn
in their lowest position, and the steam and air valves closed.

page_text: When highly bituminous coal is used in large quantities, or if a sufficient
quantity of air cannot be induced through the tubular bars or pipes to meet the
demand, 1 sometimes allow an auxiliary supply to be furnished over the fire,
through the slotted openings B¹ in the fire hole door B which can be automatically
closed with the sliding damper A as shown in Figures 1 and 2. Or, I can if
desired arrange to furnish this auxiliary supply through the air valve I' at the
foot of the bridge I as in Figures 3 and 4. The opening and closing of the valve ['
can also be regulated in consequence of its connection with the axis C. When I
want to increase the passage of air between the grate bars I do so by injecting
steam into the ashpit under the grate bars, as described in my Specification
No. 5018º1.
The cataract shewn by Figures 5 and 6 is somewhat similar to that described
and illustrated in my Specification No. 7852" except that the flexible valve E'
covering the water passages in the body of the piston E³ is placed underneath the
piston instead of above it; and the cylinder E is made to oscillate on a pin which
passes through a male and female "joint" fixed below the bottom cylinder cover
the "joint" being similar to that shown fixed at the bottom of the plunger or
piston in the cataract I described and illustrated in my Specification No. 5018º¹.
In that case the "joint" formed the oscillating centre for the rod that connected
the plunger or piston to the cataract lever; in this case the "joint" forms the
oscillating centre for the cylinder and piston rod, the latter being connected to the
cataract lever E¹; the said "joint" is bolted to a bracket that is connected to a
foundation plate which also carries the fulcrum on which the cataract lever is
poised in a similar manner to that illustrated and described in my Specification
7852ºº.
I wish it to be understood that I can apply my invention to any class of boiler
or furnace where hollow grate bars are used for conveying air into the furnaces or
to the bridge of such furnaces. Under the term "grate bar" I include together
with bars such as the drawings represent, other like tubular appliances upon or
against which the fire lies.
Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Apparatus substantially as described for supplying air in regulated quantity
to furnaces through hollow grate bars, by steam urging the air through the hollow
bars; in which apparatus there is a valve or cock so mechanically connected with
a door or slide at the entrance to the fire that the former must open with the latter
but closes independently and gradually in consequence of its connection with a
cataract or like controlling apparatus.
2. Apparatus substantially as represented by the annexed drawings whereby air
is urged through hollow fire bars under the control of a cataract or like controlling
apparatus.
Dated this 23rd day of January 1893.
SAML. OATES.