Year: 1876

page_text: PROVISIONAL SPECIFICATION left by Henry Callas at the Office of the
Commissioners of Patents on the 13th July 1876.
HENRY CALLAS, of Reading, in the County of Berks, Engineer.
IN THE CONSTRUCTION OF FLUES."
"IMPROVEMENTS
Hitherto great difficulty has been experienced, not only in curing any liability to
smoko in chimneys already constructed, but also in constructing chimneys in such a
manner as to avoid their having any tendency to do so. Now I propose to obviate
these difficulties in the following way:
.
At the throat of the chimney I build in a suitable metal lintel plate made of cast
iron of any suitable shape, and having in its centre a nozzle furnished internally on
cach side with a projection, which projections serve as supports whereon a throttle
valve of a circular, oval, or any other suitable form rests; such throttle valve may
be easily raised or depressed to any desired angle or entirely closed by means of the
hand, or with the poker or otherwise.
At a suitable distance down the flue of the chimney I fix iron spikes or other
suitable supports to serve as rests for a conical smoke tube or conductor, say about
2 ft. long, or of any other suitable dimensions. Over such conical smoke conductor
I place a circular tube, somewhat in the form of an ordinary tall boy, and projecting
at the summit of the chimney about 6 inches, or to any other suitable length. Over
the top of such circular tube I place a metal plate furnished with a suitable orifice
in its centre to permit of its dropping down over the tube, about 4 ins. below the
top of the chimney. By this arrangement I provide an annular space all round
between the sides of the chimney and the circular tube or pipe, which space
being filled with air prevents any further cooling down of the smoke and other
products of combustion during their ascension, and thus facilitates their escape
instead of, as is generally the case, retarding it owing to their increased condensation
at this important juncture of their exit.
•
Over the projecting portion of the circular tube at the summit of the chimney I
place a suitable cap or terminal, which may be made of terra cotta, or of any other
suitable material, and I prefer to construct it with its sides formed on an incline, so
as to permit any lateral currents striking against them to be diverted, and thus
readily carried into the vertical portion of the cap or terminal at its top.
The operation of my Invention is as follows:-By opening the throttle valve
fixed in the nozzle formed in the lintel plate placed in the throat of the chimney, as

page_text: before described, the products of combustion ascend; and are conducted by means
of the conical smoke tube or conductor before mentioned into the tube placed
thereon, through which they traverse readily, owing as before explained to their
non-condensation, and find a ready exit at the top of the terminal or cap.
In adapting my Invention to flues in course of construction, and where it is
necessary to gather the flues, I prefer to insert in any convenient position in the
flue two iron plates, somewhat in the form of swan necks, and of any required
dimensions; such iron plates serve to present a smooth surface against which the
smoke impinges, and thus in diminishing the friction serves greatly to facilitate the
ascension of the products of combustion through the chimney shaft.
One of the principal features of my Invention is the introduction of the nozzle in
the lintel plate, as before described, and the nearer the form of such nozzle
approaches that of a complete circle, the more perfect will be its operation from the
fact of the products of combustion converging to, and entirely filling the same, thus
thoroughly overcoming the tendency of any downward draught to drive them back
into the room.
Another feature of my Invention is that the lintel plate, which is now ordinarily
made flat, I frequently prefer to form with sloping or inclined sides, so as to permit
of the smoke or fumes finding easy access to the shaft of the chimney, and thus
precluding all annoyance from their being beaten down, and so returning into the
room.