IMPROVEMENTS IN "FURNACES
Year: 1885

page_text: COMPLETE SPECIFICATION.
"3
I WILLIAM KENT residing at 26 Highland Avenue Jersey City, in the County
of Hudson and State of New Jersey in the United States of America gentleman,
do hereby declare the nature of my invention for IMPROVEMENTS IN "FURNACES
and in what manner the same is to be performed to be particularly described
and ascertained in and by the following statement :-
My invention relates to certain new and useful improvements in furnaces and
the method of setting steam boilers (but more especially to those furnaces which
use bituminous coal, lignite, peat, wood or other fuel which contains large quantities
of tarry, or gaseous matter and in burning distils a large amount of combustible
gas, and has for its object to so construct and arrange the furnace that all of said
gases will be consumed and the heat generated thereby utilized to the best
advantage in the generation of steam, and with these ends in view my invention
consists in the details of construction and combination of elements, hereinafter
fully described, in detail explained and then specifically designated by the claim.
In order that those skilled in the art to which my invention appertains may
more fully understand its construction and adaptation I will proceed to describe
the same in detail referring by letter to the accompanying draw in which
Fig. 1 is a vertical section of my furnace as applied to an ordinary return
tubular boiler the latter being in elevation.
Fig 2 a ground plan.
Fig 3 a cross-section.
Fig 4 a section of my furnace as applied to a Babcock and Wilcox or other
water tube boiler and
Fig 5 a ground plan of the same.
Similar letters denote like parts in the several figures of the drawings.
Referring to Figs 1, 2 and 3 which show my improved furnace in connection
with a return boiler, A is the boiler which is surrounded by a wall B of brick or
other non conducting material. C is a roof of fire brick which extends just below
the boiler nearly its entire length and which has perforations D forming communi-
cation between the lower chamber of the furnace and the space next the boiler.

page_text: E is a roof of fire brick extending over the fire box and against which the direct
rays of heat are projected from the fire bed on the grate F.
G is a passage formed by the roof C and E by which direct communication is
formed between the outer atmosphere and the furnace the capacity of this passage
may be regulated by any suitable sliding gate. It will be understood that air
passing through said passage will be heated before it reaches and mingles with the
gases of combustion. H is the bridge wall which is made just high enough to
prevent any coal being accidentally thrown over it.
I J are flame walls extending from the bottom of the furnace to the roof C and
forming a passage K equal to one sixth of the grate surface Instead of these walls
a single wall may be used having a sufficient opening.
In boilers as now set especially those which have a large amount of heating
surface in proximity to the grate a large quantity of the gases distilled from the
fuel becomes chilled below the temperature of ignition by contact with the surface
to be heated and therefore pass off unconsumed entailing a great waste as well as
annoyance in choking the tubes and chimney.
To avoid this waste and annoyance it is necessary to insure the perfect ignition
of the gases before they are allowed to touch the heating surfaces of the boiler
This may be accomplished by igniting all the gases inside the combustion chamber
and giving them a long distance to travel requiring some length of time for
such travel and this is accomplished by my invention the operation of which is
as follows:-
In Figs 1, 2 and 3 the furnace proper with its grate bars is set some distance in
front of the boiler and is covered by the two fire brick roofs C E.
The gases rising from the fire bed together with the air which passes through the
grate bars and that which is admitted through the passage G between the roofs CE
after passing over the bridge wall H, meet an obstruction in the flame walls I J and
are compelled to change their direction in the combustion chamber and pass through
the narrow vertical passage K between the flame walls.
After passing through this passage they are still prevented from reaching the
boiler by the inner extension of roof C. By thus causing the gases to travel a
circuitous route through the chambers surrounded with fire brick they are
thoroughly burned and are in proper condition to give up all their heat of com-
bustion to the water in the boiler.
The perforations D serve to insure the heating of that portion of the boiler
just above the roof C by allowing a portion of the gases to pass through to said
boiler.
Figs 4 and 5 show a modification of my improvement as applied to water tube
boilers and it differs from the above described construction in that the fire box is
placed directly under the front end of the boiler the gases of combustion being
kept from immediate contact with the heating surfaces by means of a layer of fire
brick L which forms a roof for the furnace and compels the gases to pass over the
bridge wall H through the passage K and around the baffle plate M which projects
up at right angles from the roof L and from thence in the direction of the arrows
around the baffle plate N projecting down at right angles from the upper layer of
fire brick O which is supported by the upper row of tubes, and finally under the
water drum to the chimney.
Having now particularly described and ascertained the nature of my said
invention and in what manner the same is to be performed I declare that what
I claim is
1. The combustion chamber in the rear of the furnace covered by roof C in com-
bination with the flame walls I J placed in said combustion chamber.
2. In a water tube steam boiler setting the combination of the roof C of the
furnace extending from the front to a point beyond the bridge wall the low bridge
wall H and the flame walls I J substantially as set forth.

page_text: 3. In a water tube steam boiler the arrangement of the roofs C and O and the
baffle plates M and N so as to cause the products of combustion to travel nearly
the whole length of the boiler before entering the nest of tubes as shown and
described.