Appliances Improvements in Apparatus or for Consuming or Preventing Smoke in Steam Boiler and other Furnaces.
Year: 1888

page_text: Date of Application, 31st Dec., 1888
Complete Specification Left, 30th Oct., 1889-Accepted, 30th Nov., 1889
PROVISIONAL SPECIFICATION.
Appliances
Improvements in Apparatus or
for Consuming or
Preventing Smoke in Steam Boiler and other Furnaces.
I EDWARD DOBSON of the City of Montreal Canada but at present residing at
9 Ormond Street Jarrow-on-Tyne in the County of Durham Engineer do hereby declare
the nature of this Invention to be as follows:-
The object of my Invention is to provide apparatus or appliances which ensure the
consumption or burning of the products of combustion or smoke usually wasted and
the utilization of the increased heat evolved by such consumption or burning and this
without diminishing the draught of the fire or increasing the consumption of fuel.
According to my Invention I place at the rear of the bridge and proferably on the
same level as the dead place (which may form the bottom of it) an air chamber the
width of the furnace or thereabouts and into this chamber air is admitted from
the ash pit through an opening or openings at the under side of the said chamber
the admission of the air being regulated or cut off by means of a valve or damper
operated by any suitable means such as by a rod carried to the front of the furnace.
From this chamber the air passes by a large number of small openings in the top of
the said chamber which top plate is preferably inclined the inclination being down-
wards from the back of the bridge. Through the bridge over the dead plate 1 may
make passages coinciding with openings in the front of the air chamber so that hot
gases from the fuel can enter into the air chamber. By the foregoing means hot air
passes from the ash pit into the air chamber and passes therefrom through the perfo-
rations in the top thereof and so is brought in a number of small streams into contact
with the products of combustion directly they have passed over the bridge igniting
or burning those products which in ordinary furnaces are carried off unconsumed and
so I effect the entire combustion of the carbon or nearly so and consequently economize
fuel and increase the heating effect.
In order that air may be supplied as aforesaid at the times required (usually when
fresh fuel has been supplied) I may provide a self closing device which is connected
to the air admission valve or damper, so that, when the furnace door is closed the valve
is opened and closes again after a lapse of time decided by the rate at which the self
closing device is set to return to its normal position.
nithin 21 dav Dber 1888.
COMPLETE SPECIFICATION.
Improvements in Apparatus or Appliances for Consuming or
Preventing Smoke in Steam Boiler and other Furnaces.
I EDWARD DOBSON of the City of Montreal Canada but at present residing at
9 Ormond Street Jarrow-on-Tyne in the County of Durham 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 my Invention is to provide furnaces with simple apparatus or appliances
which ensure the consumption or burning of the products of combustion or smoke
usually wasted and the utilization of the increased heat evolved by such consumption
or burning and this without diminishing the draft of the fire or increasing the
consumption of fuel.
I will describe my invention with reference to the accompanying drawings Figure 1
of which is a longitudinal section of an internal flued boiler fitted with my improve-
ments and Figure 2 is a front elevation showing the connection of the furnace door

page_text: with means for automatically operating the air admission valve. Figures 3 and 4
are sections at right angles to each other of apparatus for effecting the gradual
closing of the air admission valve.
According to my Invention I place at the rear of the bridge A. of the furnace
and preferably on the same level as the dead plate a (which may form the bottom of
it) an air chamber B which may extend entirely or only partially across the width of
the furnace. Into this chamber air is admitted from the ash pit C through an
opening or openings in the bottom of the said chamber the. adinission of the air
thereto being regulated or cut off as required by means of a valve or damper D
operated by any suitable means preferably by a rod E attached to the valve and
extending to the front of the furnace where it is connected to the furnace door in
such a manner that the valve is opened when the furnace door is closed and then
closes gradually as hereinafter described. The top plate of the chamber B is
preferably inclined downwards from the back of the bridge A and is perforated with
a large number of small holes through which the air passes from the interior of the
chamber into the flue F. 1 sometimes also make perforations or openings in the
front plate of the air chamber B coinciding with similar perforations or openings
made horizontally through the bridge A so that hot gases from the fuel can pass
through these openings into the air chamber B and mingle with the air admitted
thereto by the valve D. The heated air from the ash pit entering the air chamber B
passes therefrom through the perforations in the top bund so is brought in a number
of small streams into contact with the products of combustion from the furnace
directly they have passed over the bridge A thereby igniting or burning these
products which in ordinary furnaces are carried off unconsumed, and so effecting
the entire combustion or nearly so of the carbon and consequently economizing fuel
and increasing the heating effect.
In order that air may be supplied as aforesaid at the times required (usually when
fresh fuel has been supplied) provide the valve or damper D with a self closing
device G Figure 2 which is connected to the furnace door in such a manner that
when the furnace door is being closed, after feeding the furnace for instance, the
air admission valve is opened, and then closes again automatically after a lapse of
time decided by the rate at which the self closing device is set.
This automatic valve closing device is shewn in sectional elevation in Figures
and 4 and consists of an oscillating cylinder El containing a piston I the said cylinder
being charged with oil or other suitable liquid, which, when the piston moves in the
cylinder passes from one side of the said piston to the other side thereof either
through perforations in the piston or through a port, leading from one end of the
cylinder to the other, according to the direction in which the piston is moving. The
piston I is connected by its rod K to one end of a double arined lever L fast on a
spindle M mounted in bearings in the frame or casing G of the apparatus. The
opposite end of the lever L carries a counterweight N which tends to maintain the
piston at the upper end of the cylinder.
One end of the spindle M projects outside the casing G and carries on the
projecting end another lever O the lower end of which is connected by a rod P to
one arm of a bell crank Q centred at p to any convenient part of the front of the
furnace frame. The other arm of this bell crank is connected by the rod E to the
air admission valve D so that when the lever O is oscillated as hereinafter described
it effects through the connections referred to, the opening and closing of admission
valve D.
The upper end of the lever O carries a pin or stud R which engages a tooth or
When the furnace door is
projection on a rod S hinged at s to the furnace door T.
opened for the purpose of feeding the furnace with fuel the rod S slides over the
pin or stud R until the door is opened a certain distance when the tooth or projection r
passes over the stud R so as to engage therewith when the door is being closed.
When the door is being closed the projection, being engaged with the stud R
imparts motion to the lever O in the direction of the arrow thereby giving a partial
rotation to the spindle M and through the lever L forcing the piston I towards the

page_text: lower end of the cylinder the counterweight N on the opposite end of the lever L.
being at the same time raised. The oil or other liquid in the cylinder H passes (as
the piston descends) through the perforations in the piston from beneath to the
upper side of the said piston and is prevented from returning through these perfora-
tions (when the piston rises in the cylinder) by a valve or valves k. The lever O
being moved by means of the tooth and stud R as described effects, through the
connections with the lower end thereof, as hereinbefore described, the opening of the
air admission valve D so as to admit air from the ash pit into the chamber B behind
the fire bridge, from whence it passes into the flue, and by mingling with the products
of combustion from the furnace effects their more perfect combustion as hereinbefore
described.
When the furnace door is nearly closed the outer end of the rod S, which is
curved or bent as shewn at t comes into contact with a fixed stul or projection so
that in closing the door, the rod S is raised and the projection or tooth disengaged
from the stud or pin R. The lever O being thus released will by the counterweight N
on the lever I be moved in the reverse direction to that indicated by the arrow and
the piston I be raised in the cylinder H and as the oil in the cylinder is prevented
by the valve or valves & from passing through the perforations in the piston I it is
compelled to pass from the upper side of the piston to the underside thereof through
the port or passage. The speed at which the piston moves upwards in the cylinder
is governed by the size of the passage through the port and this may be regulated
by means of the screw valve 1." It will therefore be understood that by reason of
the connection of the air admission valve with the lever O, the time which the air
admission valve D remains open after the furnace door is closed will depend upon.
the speed at which the oil or liquid in the cylinder H is permitted to pass through
the port and that this may be regulated as desired.
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. In steam boiler and other furnaces an air chamber situated close behind the
fire bridge and communicating at the bottom with the ash pit and having the
top perforated with a great number of small holes through which heated air
passes from the interior of the chamber to mingle with the products of combus-
tion passing over the bridge substantially as and for the purposes hereinbefore
described.
2. In steam boiler and other furnaces an air chamber situated close behind the fire
bridge and communicating with the ash pit, the top and one side of the chamber
being perforated the perforations in the side coinciding with perforations or passages
in the fire bridge substantially as herein before described.
3. The combination with the subject matter of either of the preceding claiming
clauses of means substantially as hereinbefore described for automatically admitting
air from the ash pit to the flue behind the fire bridge when the furnace door is
being closed, and for gradually cutting off the supply of air after the furnace door
is closed.
4. The general combination and arrangement of parts constituting means for
effecting the burning or consumption of smoke in furnaces substantially as herein-
before described and illustrated by the accompanying drawings.
11:20:1 Lataka 1000
J. H. JOHNSON & Co.,
Agents.