IMPROVEMENTS IN STEAM- BOILER AND OTHER FURNACES
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by George Froderick Redfern at the Office
of the Commissioners of Patents on the 1st March 1880. A communication
from abroad by Frank Wendell Brainerd, of Freeport, Illinois, United States
of America.
GEORGE FREDERICK REDFERN, of the General Patent Office, 4, South Street,
Finsbury, in the County of Middlesex, Patent Agent. "IMPROVEMENTS IN STEAM-
BOILER AND OTHER FURNACES." [A communication from abroad by Frank Wendell
Brainerd, of Freeport, Illinois, United States of America.]
The Invention communicated to me relates to devices for supplying steam and
air to the fire chamber of furnaces to assist combustion.
The object of this Invention is to consume the products of combustion, which
would otherwise produce smoke and pass off into the open air, by directing into a
furnace jets of oxygen or air intermingled with the hydrogen of steam, together
with streams of air alone, in such a manner that all of the products of combustion
arising from the burning fuel will be fully and thoroughly ignited, and hence
consumed.
A further object is to provide a furnace door with means for introducing streams
of air into the furnace at any desired angle to the surface of the burning fuel, or
entirely cut off the same from the furnace.
The doors of the ash pit and the doors of the furnace are of the ordinary
construction.
A steam pipe connects with a pipe baving a stop-cock to the upper part of
the boiler, and extending across the front of the wall of the furnace with vertical
extensions reaching downwardly, and having attached at right angles to their
lower ends by any suitable means injectors, which form continuations of the
extensions.
Outlet-pipes conduct combined steam and air to the furnace. These outlet-pipes
are set in the walls of the furnace on either side of the furnace doors in a horizontal
plane at a height just above the surface of the fuel upon the grate bars, and not so
high that a line drawn from them would be above the fire wall. Those next the
side walls have a sufficient horizontal curve in the direction of the centre of the
furnace to direct the steam and air-jets toward the centre of the length of the bridge
wall, where the products of combustion are the thickest, and at their highest
temperature. The ends of these pipes project upon the outside sufficiently beyond
the walls to permit of the attachment of an elbow.

page_text: To the lower end of the elbow is attached in a vertical line an air supply pipe
of about the same length as the outlet-pipe, which may be straight or flaring at its
mouth.
In a modification of the air-supply pipe a T joint is used instead of an elbow,
extending the pipe above the outlet-pipe so as to obtain a current of air from two
directions.
The steam-pipes are connected to the air and outlet pipes by passing the injector
in a horizontal plane with the outlet-pipe through a perforation in the elbow
or T joint. By this means a jet of steam and air is conducted in a direct line
into the furnace, and at such a distance from the opening of the air-supply
pipe that there will be little or no noise from the rush of the steam and air, and
at the same time provide a direct current of air in the supply-pipe.
In the doors of the furnace is a rectangular opening for inserting the draughts,
which, when closed, entirely fill the opening. These draughts have perforations
extended through them from edge to edge, and are pivotted to the doors, so that
when closed no air will be admitted. The perforations are made quite large at
their upper end, but converge toward the centre and terminate in a small neck,
and are in outline like the bowl and stem of an ordinary goblet. To the neck of
this perforation is attached a removeable extension in such a manner that it will
not interfere with the opening and closing of the draught,
By the above construction it will be seen that not only may the current of air
be cut off through the draught, but it may be directed at any desired angle into
the furnace or upon the fuel, and that a supply of air is thus obtained between the
currents of air and steam to complete combustion, thereby consuming the smoke,
and at the same time economizing the amount of steam otherwise necessary for
this purpose.
The operation of the device is as follows, namely:-Having fired up until steam
has formed in the boiler the stop cock is turned, and admits the steam to the pipes.
As a vacuum is formed by the escape of the steam from the injector through the
inlet pipe into the furnace the air rushes in from the supply pipe, and is commingled
with the steam, thus producing a blast of oxyhydrogen to assist combustion in the
furnace.
About the time the steam is turned on the air draughts in the doors are opened
to introduce a current of air between the streams of air and steam. By practical
experiment it has been found that some of the products of combustion accumulate
between the streams of oxyhydrogen, and that by having the intermediate
adjustable air-draught to introduce a current of air between these streams they
are entirely consumed.