Improved Method of and Device for Automatically Regulating the Draught in connection with Grate Furnaces.
Year: 1895

page_text: Date of Application, 8th Mar., 1895-Accented, 23rd Nov., 1895
COMPLETE SPECIFICATION.
Improved Method of and Device for Automatically Regulating the
Draught in connection with Grate Furnaces.
I, THEODOR LANGER of 21 Nussdorferstrasse Vienna IX in the Empire of
Austria, Engineer, do hereby declare the nature of my said invention and in what
manner the same is to be performed, to be particularly described and ascertained
in and by the following statement :-
This invention relates to a method of preventing superfluous air being fed to
fire grate furnaces, with or without smoke consumers, this being effected by
automatically regulating the current of air admitted to the combustion chamber.
In order that the carbon as well as the products of combustion may be converted
into carbonic acid mixed with water in the most favorable proportion i.e. in order
that with the smallest body of air, the best possible combustion may be effected, it
is necessary not only to regulate the upper current of air (i.e. the air delivered
above the grate) both as to time and volume but also to reduce the current
delivered below the grate, in relation to the consumption of the fuel and the
diminishing height of the layer of such fuel on the bars.
Further it is necessary to reduce the draught or current of air fed to the furnace,
during charging, to that minimum which at the same time prevents the gases
being driven back; a disadvantageous current of air through the open fire door is
thus obviated.
Finally, immediately after each charge (ie. when the largest quantity of air and
generated products of combustion is present), care must be taken that a sufficient
draught is passing through and out of the fire box.
The best and most economical method of supplying air to the combustion chamber
of fire-grate furnaces, therefore, must allow of such a regulation that first, on
charging, the least quantity of air is automatically fed to the combustion chamber,
that secondly on the gases commencing to generate, the greatest quantity of air is
delivered and, thirdly, during the intervals of charging, a current is delivered
which is reduced according to the gases generated and in relation to the reduced
height of the burning layer of fuel.
Such a method of automatically regulating the draught forms the subject-matter
of this invention and will now be described in connection with the smoke consumer
described in my Patent No. 15542 of 1892 and as a special improvement in fire
grate furnaces for stationary boilers.
An arrangement specially adapted for effecting the aforementioned automatic
regulation of draught at all times from charge to charge is shown on the accom-
panying drawing in elevation in connection with a fire door. The admission of
the upper current of air, which corresponds, both as to quantity and time, with the
generation of gas, as also the limitation, regulation and mixing of such air at every
moment during the period of gas generation for causing the smokeless combustion
of the gases present, is effected according to the method and arrangement described
in my Patent No. 15542 dated 30th August 1892.
The new feature of this invention is the device for transmitting the movements
of the opening and closing fire-door, to the cataract K and to the smoke damper R
in the manner hereinafter described.
The closing of a disc attached to the perforated fire-door and admitting air
above the bars, and which is always subject to the influence of a weight P, as well

page_text: as the movement of the damper for regulating the draught, is effected by the
cataract K.
b
The distribution of the upper current of air regulated both as to time and
quantity and which is fed into the combustion chamber, is effected in such chamber
by means of a steam-injector (not shown in the drawing) as described in my
said previous Patent.
The steam enters through valve v and pipe winto a steam injecting pipe arranged
in the fire box. On opening the fire door, the piston of the cataract K is forced
upwards by means of intermediary parts to be afterwards described, whereas on
closing same, such piston is not operated reversely with equal speed, but descends
with a rapidity, which can he regulated, according to the nature of the fuel, by
means of a governor valve D admitting air into the cataract K above the piston or
diaphragm in such manner, that only such air is allowed to enter the combustion
chamber through the rotary disc as is necessary to effect the thorough combustion
of the gases generated. The transmission of the movement of the fire-door to the
rest of the apparatus is effected in the following manner :-
On opening the door, the smoke damper R descends until it reaches the lowest
permissible point; whereas, ou closing same again, the damper ascends to the
highest position allowed by the charge.
The subsequent regulation of the upper current of air and the inlet of the lower
current of air, by gradually reducing the entrance of the passage leading to the
chimney or to the grate and in accordance with the quantity of gas generated and
the reduced height of the burning layer of fuel, is likewise effected by the cataract K,
which uniformly regulates the upper current of air both as to time and volume, as
described in my aforesaid prior Patent No. 15542 of 1892.
On the axle of the fire-door is mounted a sleeve H having a lever 10, which
latter is provided at its lower end with a stop resting on a stop A on the upper
hinge of the fire door. This sleeve H has a second stop 6 on its upper part.
Above the sleeve H is mounted a second sleeve H¹ having a stop 61 and a
bevel-wheel 4. On opening the fire-door, therefore, the stop A carries with it the
sleeve H and this in turn the sleeve H' and the bevel wheel 4, which latter then
transmits these movements to the wheel 3. A lever 5 is keyed onto the axle of
wheel 3, the free end of which lever is linked to a collar 7 and thus raises same,
at the same time forcing the piston upwards by pressing against the end B of the
piston rod, the air in the cataract K being thus forced out through the air-flap L.
The rotary disc on the door provided with a weight P for holding same in the
position in which the airways are open, must be rapidly closed to such an extent
immediately after each charge, that only a body of air corresponding to the nature
and quantity of the fuel at the commencement of the period of gas-generation and
necessary for the smokeless combustion of the combustion gases is admitted into
the combustion chamber.
This sudden part-closing of the disc (ie. the bringing of same into its commencing
or slightly-open position) is effected on closing the fire-door, viz. on the lower stop
of the sleeve H becoming free from stop A, by a weight 1, connected to the lever 5
and collar 7 falling as far as required down the piston rod b and thus imparting to
the disc a certain sudden jerky movement which closes the openings of the latter
through the medium of wheels 3, 4 sleeve H, lever 10 and rod 9.
The fall of the collar is limited as desired by an adjustable stop 8.
When the collar 7 comes in contact with the stop 8, the weight I cannot descend,
nor the disc close, farther than the extent to which the cataract piston may be made
to descend by admitting air through the valve D into the cataract K. The stop 8
may be fixed in such a position that the distance to be travelled by the lever 5
before it strikes the same corresponds to that required for effecting the immediate
and complete closing of the fire door.
It will therefore be evident that the stop 8 may be arranged in any position,
arcording to the extent to which the disc is to be opened and to the nature of the
fuel, method of firing and the draught.

page_text: The damper R is connected to the piston rod 6 of the cataract through the
medium of chains cc secured to the segment G and passing round the roller 13 to
the bent connecting arm a secured to the lower end of the piston rod b and below
the stop 8. The segment G is necessary seeing that the movement of the piston is
far from sufficient to actuate the damper to the extent required.
* 1
In order to prevent the damper R being opened too wide (which would occur if
the movements of the cataract directly acted on or influenced such damper) and to
cause the smoke damper to take up its lowest position as rapidly as possible on the
fire door being opened, the axle 10¹ of roller 13 is mounted in a long arm or lever 17
pivotted to lever 14 by pin 16.
During the opening of the door, the cataract-piston b draws the chain c with it;
on account of the weight of the smoke damper, however, the arm 14 is raised to the
extent to which its small arm slides down the cam 15 of a sleeve H2 keyed on the
axle of the fire door.
It will be evident that on account of the shape of the cam 15 and the two
arms 14 and 14', it is possible to make the damper lower to any desired extent, in
spite of the ascent of the cataract piston. On closing the fire-door again, the
arm 14 under the influence of the cam 15 takes up its lower position, when
the damper R is thus rapidly raised.
According to this improved arrangement, therefore, the damper R connected by
the chains c to the cataract piston, closes slowly in the same ratio as the latter
descends.
In order to preserve the piston, the weight of the damper is so regulated or
counterbalanced that the latter falls or closes automatically.
The adjustability of the rotary disc and the damper is very important. The
extent to which the damper is opened and the time same is kept open, must be
regulated according to the nature of the fuel, the manner of working and the
strength of the chimney draught.
As soon as the operation of the cataract by the air valve D and the commence-
ment of opening the disc as regulated by the adjustable stop 8, is found by
experiment, the manner of closing may be altered or regulated by altering the
securing point of the rod 9 on lever 10.
It is also necessary that the largest opening of the damper (whose lowest position
is limited by the lever 17 carrying roller 13 around which the chain c runs coming
into contact with the stop 21) may be correctly determined.
For this purpose, the roller 13 is not mounted directly on the lever 14 but ou the
lever 17 pivoted to the latter; the extent of opening the damper, therefore, may
be regulated by altering the angle formed by said levers 14 and 17, by means of
screw 18.
Having now particularly described and ascertained the nature of this inven--
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. Improved method of effecting a smokeless and economical consumption of fuel
in grate-furnaces, according to which method not only the top or upper current of
air necessary for the smokeless consumption of the gases generated during the
period of gas generation, but also the bottom air supply is automatically regulated
by the same regulator and in such manner that the air admitted during the period
of gas generation to the time of re-charging is reduced in volume according to the
quantity of gases generated and the fuel consumed, in order to prevent an excess of
air after the gases are generated and during the conversion of the carbon into
carbonic-acid, substantially as described and shown.
2. A device for carrying out the method set forth in Claim 1, by means of which,
on opening the fire door, the smoke damper connected with same is closed and is
opened again on closing the fire door, while a cataract (K) put under tension when
the fire door is open, but released again when same is closed, regulates the inlets
for the admission of top-air into the combustion chamber and simultaneously

page_text: '
operates the smoke damper in accordance with the quantity of gases generated and
the quantity of fuel consumed, whereupon steam, injected over the burning fue!
prevents the supply of top-air rising and escaping, and mixes with the gases.
'substantially as described and shown in the drawing.
3. In a device as described in Claim 2, the arrangement of the mechanism for
operating the smoke damper and the cataract influenced by same, on the axle of the
fire door and the rotary slide for the top-air, on the fire door itself, in such manner
that, on opening the latter, a roller (13) with its axis (10) may be so raised, that a
greater upward movement of the damper by its weight is permitted than to
the cataract-piston connected by chain running over said roller (13) while, on
closing the fire door, the roller (13) is forced downwards and thus rapidly opens the
damper, the cataract being at the same time set free, the chain thus slowly
returning and gradually closing the disc on the fire-door, substantially as described
and shown.
4. In a device as described in Claim 2, the construction of the operative parts as
sleeves mounted on the fire door, of which sleeves the lower one (H2) is operated
by the lower hinge of the door, the central one (H) by the upper hinge, and the
lower one (H¹) by the central sleeve (H), through the medium of the
stops (A, 6, 61), whereby the lower sleeve (H 2) operates the small arm of the lever
by a spiral cam (15), in the larger arm of which lever is mounted a roller (13)
connected by chain to the smoke damper, while the upper sleeve puts the cataract
under tension by means of the bevelled wheels (4, 3), said cataract, on closing the
fire door by the return of the stop (A) set free simultaneously with the central
sleeve (H) closing the rotary slide by means of the upper sleeve (H') stops (6, 6¹)
central sleeve (H¹) lever (10) and rod (9), substantially as described and shown.
5. A device as described in Claim 2, in which the extent of opening the rotary
slide, for the top-air and the length of time for keeping such slide adjustable by
stop (8), uniformly open during the period of gas generation is determined by
arranging a collar (7) on the rod of the cataract, which collar on ascending carries
with it said rod of the cataract but ou descending falls as far as the adjustable
stop (8) and operates the gear (5, 3, 4, 6, 10, 9) for the rotary slide in relation to
the position of the sleeve (7) between the stop (B) and stop (8), substantially as
described and shown.
6. In a device as set forth in Claim 2 a roller (13) for regulating the position of
the smoke damper (R), such roller being in connection with the cataract-piston and
mounted in levers (14, 17) in such manner that the position of such roller may be
altered by a screw (18) for adjusting the relative angle of the arms (14, 17) to each
other, substantially as described and shown.
Dated this 8th day of March 1895
BOULT & WADE,
Agents for the Applicant.