Improvements in or relating to Boiler and other Furnaces.
Year: 1893

page_text: Date of Application, 23rd May, 1893-Accepted, 22nd July, 1893
COMPLETE SPECIFICATION.
Improvements in or relating to Boiler and other Furnaces.
I, FRIEDRICH STEFFENS of Rödingsmarkt 46 Hamburg in the Empire of
Germany, Merchant 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 :-
This invention relates to furnaces for heating steam boilers or for other purposes
and has for its object to adapt my system of smoke-burning for internal furnaces,
by creating contrary currents of the incoming feed air and the exiting fire-gases,
which thus meet each other constantly. It has moreover for its object to supply
the furnace gases after requirement with dry, or with moist hot air, which improve-
ment I consider as a principal innovation of my system, as it affords special
advantages for using very inferior fuel, such as woodshavings, sawdust etc. Such
fuel which offers a great surface to the heat produces with ordinary furnaces, fed
with dry air a great deal of smoke, especially at the moment of charging. This is
prevented by my construction and by using moist hot air, instead of dry air, by
which former the combustion goes on more evenly, without producing much smoke,
even at charging the furnace.
My invention consists principally in a construction for providing the furnace with
moist hot air for preventing unnecessary produce of smoke and for consuming or
completely burning up the combustible matters in the smoke by contrary currents
of the feed air and the exiting gases. This consists of one, two or more upright
walls of fire bricks erected. across the furnace.flues at. a. conveniant distance behind
the fire. bridge. The walls are based on a cast iron box or air chamber inserted in.
the furnace flues, they do not quite reach to the roof and are so placed as to leave
a certain distance between each other. The walls are pierced by a suitable number
of openings to allow the exiting fire gases to pass through them. These openings.
are preferably vertical slits. In the body of the walls are a number of rising air
channels opening below in the cast-iron air supplying chamber common to all. This
chamber recives air from a main air channel, let through the space below the grate.
The main air channel is in communication with an arrangement for vaporisation of
water, which is placed likewise in the space below the grate. From the heat in
this space the water evaporates and partly enters into the furnace from below
through the grate, and partly it streams into the main air channel where it is mixed
up with the feed air. The feed air saturated with aqueous vapour is let from the
main air channel through air regulators into the air supplying chamber and the. air
channels of the. walls, so that the moist air is heated to a very high temperature and
issues into the combustion chamber behind the fire bridge in a contrary direction as
the fire gases are drawn off and tend to completely burn up all combustible matter
therein. The regulators to regulate the velocity of the current of heated air
inserted between the main air channel and the air supplying chamber consists of
small iron plates perforated with holes. These regulators serve at the same time
as heating bodies for the passing air. They allow the air to pass through, only in
small portions, so that it gains time to be more thoroughly heated and to ascent
evenly to the air channels of the walls.
The accompanying drawings illustrate the improved furnace,
Fig. 1 being a longitudinal section,
Fig. 2 a vertical section through the furnace as well as the air regulator and
brickwork in rear of bridge and
Fig. 3 is a longitudinal section through an air regulator in a larger scale.
7 is the air inlet main channel, which may be provided with a suitable damper r
AL

page_text: air supplying chamber n. mm are the walls of fire bricks with channels ss through
which the feed air, saturated with aqueous vapour is led into the combustion room
in a contrary direction to the gases which exit through the vertical slits between
the upright pieces of the fire bricks. The direction of the currents of air and gases
are indicated by arrows in the figs. of the drawings. o are the regulators for the
velocity of the current of the heated air the construction of which is shown in Fig. 3.
p. are the iron plates, perforated with small holes q.
The construction of the vaporisator is shown in Figs. 1 and 2. a is a tube,
which may have any convenient shape, and which is placed in the space beneath
the grate. This tube has at the upper side small holes 6 through which the vapour
can exit. The tube is fed with water by a convenient supply-pipe t.
In consequence of the heat under the grate the water in this tube evaporates and
ascents partly through the grate into the burning place for the fuel, and partly it
passes through the connecting tubes c into the main air supplying channel where it is
mixed with the feed air and brought into the air supplying chamber n and to the
channels ss' of the walls m m.
From the openings s' the superheated air saturated with vapour passes into the
combustion chamber. The moist hot air thus introduced, does not only serve to
prevent and consume all smoke, but it also enlarges very considerably the
calorific power of the fuel, the consumption of which is therefor reduced in the
same scale.
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. With internal boiler furnaces and other forms of fuel combustion furnaces and
the like, the construction of one or more upright walls of fire bricks, erected across
the furnace flues at a convenient distance after the fire bridge, based on a cast iron
air supplying chamber, these walls consisting of a number of divisions, separated by
flame passage slits and having air channels communicating with the air chamber n
and channel and opening at s' into the combustion space through which the feed
air passes, in a contrary direction to the exiting fire gases for the purpose as set
forth.
2. With internal boiler furnaces and the like, constructed after Claim 1, the
combination of a water evaporiser in the space below the grate; communicating
with the main air channel for the purpose as set forth.
3. With internal boiler furnaces and the like constructed after Claim 1, the air
regulators o between the main air channel and the air supplying chamber consisting
of perforated iron plates p to regulate the velocity of the current of heated air
substantially as set forth.
Dated MA 02-1 1002