Improvements in Boiler Furnaces.
Year: 1896

page_text: Date of Application, 1st Dec., 1896-Accepted, 6th Feb., 1897
COMPLETE SPECIFICATION.
Improvements in Boiler Furnaces.
I, DUDLEY DRIGGES FLEMMING, Gas Engineer, of 257 York Street Jersey City, in
the County of Hudson and State of New Jersey, United States of America,
do hereby declare the nature of my 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 an improvement in the construction and arrangement of
furnaces for heating steam boilers, and has for its object greater economy in the
combustion of fuel and a more thorough distribution of the resulting heat, and a less
laborious system of furnace stoking than that now in use.
In steam boilers as now used, the system practised in firing them is to charge the
fuel in the firebox to a depth of from six to twelve inches. This is distributed over
a comparatively large area of grate surface, and the result is, that owing to the
slight resistance or impediment of the passage of the air through the incandescent
fuel, the ultimate of combustion or carbonic acid gas is instantly reached and the
only useful effect realized in generating the steam is the surplus heat which this gas
parts with in its passage through the tubes to the off-take chimney, which is but a
small percentage of the energy possessed by the fuel.
To produce these reactions, it is necessary to have a furnace of sufficient capacity
to contain a large mass, in depth, of fuel and of sufficient volume to maintain a
slower generation of the gases. With this end in view I construct my furnace of
large proportions so as to contain many times the volume of the fuel as now used,
and also to reduce the grate area. To maintain an uninterrupted volume of heat, it
is necessary to construct the furnace with a series of sections operating in conjunction,
so that they may be alternately charged or cleaned, and also to always maintain
sufficient heat to ignite the gases when they are subjected to contact with the
secondary air supply, or when bituminous coal is used as fuel, to consume the carbon
vapour or smoke.
I will describe a furnace embodying my invention and then point out the novel
features in the appended claims.
Reference is to be had to the accompanying drawings forming
a part of this
specification, in which similar characters of reference indicate corresponding parts
in all the figures.
Figure 1 is an end elevation of a furnace embodying my invention;
Figure 2 is a vertical section thereof;
Figure 3 is a longitudinal section on the line 3-3 of Figure 1; and
Figure 4 is a horizontal section on the line 4-4 of Figure 3.
Referring to the drawings, A designates the outer walls or brick-work of the
furnace, in the upper portion of which is supported a tubular boiler A'. Extended
longitudinally between the outer walls A, is a partition A2 and arranged trans-
versely near the front end is a bridge wall A³, thus forming the two chambers B, B
of the furnace.
These chambers open into a flame bed a, beneath the boiler A'. Through the
front wall, each chamber of the furnace is provided with a charging opening a¹,
closed by a door, and also with doors a leading to the furnace and also to the ash
pit. Below these doors a² are valve openings a³ for the purpose of regulating the
admission of primary air below the grate bars.

page_text: It will be seen that these furnace chambers are of much greater height and length
than width, thus providing for a considerable depth of fuel on a very small grate
surface area.
Leading into each chamber of the furnace is a valve regulated pipe a', for
supplying either steam or water, which is allowed to trickle down on the fuel mass in
the furnace for the purpose of supplying the necessary water-vapour.
The flame bed a is divided into a series of combustion chambers; as here shown
there are three of these combustion chambers, B', B2, B3. At the front end of the
combustion chamber B' and arranged transversely over the flame bed is an air supply
hood b, and similar hoods b', 62 are provided for the combustion chambers B2, B5.
These hoods communicate respectively with the outer air through ducts 63, 6 and 6,
which extend through the partition A2 and have valved openings 6 through the
front wall of the furnace. These several ducts and hoods are designed to supply the
secondary air.
In the operation of the furnace, the fuel is charged so as to completely fill the
chambers to the height of the connecting opening over the partition wall, and when
thoroughly ignited the valves for the admission of the primary air are so adjusted as
to admit only sufficient air to form carbonic oxide gas. The steam or water is also
admitted, and becoming vaporized passes up through the incandescent mass of the
fuel and is decomposed. These resulting gases pass from this generating chamber
into the first combustion chamber B, where they partially combine with the
secondary air which is admitted through and regulated by the secondary air valve
for the duct 3. From this chamber they pass to the second and third combustion
chambers where the same process is repeated, each chamber being provided with
and regulated by its own secondary air duct. At this point the combustion is
completed and the resulting carbonic acid gas being highly heated passes into and
through the return tubes to the off-take chimney, gradually parting with its heat as
it moves along.
Owing to the large cubical capacity of the furnace, there is a complete control over
the combustion of the fuel and the formation of slag is obviated, and I have found
that the furnace may be worked for twenty-four hours or more without attention
except the necessary charging with the fuel, thus the labor required to operate
the furnace is very much reduced in comparison with the present system.
Having now particularly described and ascertained the nature of any said
invention, and in what manner the same is to be performed, I declare that what
I claim is,
1. A furnace for steam boilers, having a fuel capacity of greater height than
thickness whereby
a substantially slow generation of gases is generated in large
volumes, substantially as specified.
2. A furnace for a steam boiler, comprising a series of chambers communicating
one with another above a separating partition, each chamber having a greater height
than width, means for admitting primary air to each chamber consisting of valve
controlled openings through a wall of the furnace below the grate bars in the
chambers, valve controlled pipes leading into the chambers, and a hood extended
transversely over the flame bed at the front end of each combustion chamber, each of
said hoods having communication with the outer atmosphere through valve controlled
ducts in the partition wall, substantially as specified.
Dated this 1st day of December 1896
A. M. & WM. CLARK,
53 Chancery Lane, London, Chartered Patent Agents.