CERTAIN IMPROVEMENTS IN APPARATUS APPLICABLE TO FLUES OR CHIMNIES, FOR THE PURPOSE OF INCREASING THE DRAFT THEREIN, AND PROMOTING THE COMBUSTION OF FUEL
Year: 1843

page_text: TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
TAPPAN, of Fitzroy Square, in the County of Middlesex, Gentleman, send
greeting.
WHEREAS Her present most Excellent Majesty Queen Victoria, by Her
Royal Letters Patent, under the Great Seal of Great Britain, bearing date at
Westminster, the Thirtieth day of May, in the sixth year of Her reign, did, for
Herself, Her heirs and successors, give and grant unto me, the said John
Tappan, Her especial license, full power, sole privilege and authority, that I,
the said John Tappan, my executors, administrators, and assigns, and such
others as I, the said John Tappan, my executors, administrators, or assigns,
should at any time agree with, and no others, from time to time and at
all times during the term of years therein mentioned, should and lawfully
might make, use, exercise, and vend, within England, Wales, the Town
of Berwick upon Tweed, and in all Her Majesty's Colonies and Plantations
abroad, and in the Islands of Jersey, Guernsey, Alderney, Sark, and Man, an
Invention of "CERTAIN IMPROVEMENTS IN APPARATUS APPLICABLE TO FLUES OR
CHIMNIES, FOR THE PURPOSE OF INCREASING THE DRAFT THEREIN, AND PROMOTING
THE COMBUSTION OF FUEL," being a communication from a foreigner residing
abroad; in which said Letters Patent is contained a proviso obliging me, the
said John Tappan, by an instrument in writing under my hand and seal,
particularly to describe and ascertain the nature of the said Invention, and
in what manner the same is to be performed, and to cause the same to be
inrolled in Her Majesty's High Court of Chancery within six calendar months
next and immediately after the date of the said in part recited Letters

page_text: and at large appear.
NOW KNOW YE, that in compliance with the said proviso, I, the said
John Tappen, do hereby declare that the nature of the said Invention, and the
manner in which the same is to be performed, is particularly described and
ascertained in and by the following description thereof, reference being had to
the Drawings hereunto annexed, and to the letters and figures marked thereon
(that is to say):-
The Invention communicated to me, and for which I have obtained the
above in part recited Letters Patent, consists of certain new and useful
improvements or mechanical contrivance to be applied to the discharge flues
or chimnies of furnaces, for the purpose of increasing the draft thereof, and
thereby promoting combustion of fuel, the said improvements being peculiarly
adapted to the flues of furnaces or fire-places for burning anthracite coal;
and in order that the Invention may be perfectly understood I have shewn in
the accompanying Drawings the manner in which the improvements are
carried into effect. Fig. 1 represents a vertical section taken through the
centre of the upper part of a chimney flue having the improvement applied
thereto. Fig. 2 is a top view of the same. Fig. 3 exhibits the arrangement
of the discharging apertures of the air chamber, to be herein-after described.
A (Figures 1 and 2) represents the top or upper portion of the discharge flue
or chimney of a steam boiler or furnace, or that part thereof from which the
smoke and gases or other waste volatile products of combustion finally escape
into the atmosphere. A chamber B, B, constructed of two connectric tubes
or cylinders a, b, (situated at a little distance apart from each other, and
jointed together or otherwise connected at their lower ends,) is placed as seen
in Figures 1 and 2, the space between these tubes constituting the chamber.
The upper portion of the chamber or space between the tubes may be left
open, or the same may be covered over by plate suitably extending from one
tube to the other, through which plate a series of orifices may be formed for
the discharge of air from the air chamber B, B, into the flue A, or instead of
the said orifices and plate the upper part of the outer tube, may be brought
quite near the inner tube, or so as to contract the chamber or diminish the
.width thereof at its top or the part at which the air is expelled. The diameter
of the external tube of the air vessel B, B, is somewhat less than that of the
interior of the chimney A, and this air vessel is supported in its position
therein by means of any number of arms c, d, Fig. 2, extending from its
external surface to the interior of the chimney or in any other convenient
manner. The air chamber so constructed communicates by means of a pipe C,
a

page_text: with an ordinary fan blower or revolving blast wheel or other suitable blowing
apparatus, the said pipe C opening into the chamber, and extending therefrom
through the side of the chimney, and thence to the blowing machine. Now
when a powerful current of air is thrown by the blast apparatus through the
pipe C into the chamber B, B, it will rush out the top of the chamber with a
velocity proportional to the force by which it is propelled through the pipe,
and as the expelled air rises from the chamber it comes into contact with the
ascending current or column of heated air, smoke, or gases, proceeding from
the burning fuel of the furnace, and discharges the same from the chimney,
thereby creating a powerful draft up the chimney and through the combustible
matter of the furnace. It has been customary, heretofore, in the application
of a blast pipe to a furnace, to introduce the same into the ash-pit or beneath
the fire-grate or under the fuel, but by this improved method of arranging the
blast it acts above the fire. In order to greatly facilitate the escape of smoke by
means of the blast thus introduced into the chimney, I insert between the inner
and outer cylinders or tubes a, b, a series of curves or helical partitions e, e, e, each
of which is placed at a short distance apart from that immediately succeeding
it, and extends from one tube to the other and some distance downwards from
the tops of the tubes, as seen in Fig. 3, the said Figure being an elevation of
the air chamber as removed from the chimney, and exhibiting a portion of the
tube b, as broken away in order to shew the arrangement of spiral or helical
partitions above mentioned. The spaces f. f. f, formed between the helical
partitions constitute so many openings or curved passages for the discharge of
air from the chamber B, which air rushing through these passages diverges
more or less from a vertical line, and ascends from the chamber with a
whirling motion. The centrifugal force thus generated by the said motion in
the particles of the ascending currents of air causes them to be thrown
or spread out more or less laterally, and thus materially increases the effect of
the expelled currents on the smoke and air in the chimney, and, as a con-
sequence, greatly improves the draft of the chimney. Although the chamber
B, B, is described as being constructed of concentric tubes in the manner set
forth, there are various other shapes in which the said chamber may be
formed. It may be a single cylinder having the spiral or helical discharging
orifices in its top, or it may be otherwise conveniently arranged, but I
generally prefer the construction of the said chamber as exhibited in Fig. 1, as
in this case the currents of smoke proceeding from the furnace rise through
the interior of the inner tube a, as well as on the exterior of the outer tube b,
of the air vessel, and thus a very great superficial area of discharged air is
exposed to contact with the ascending column of smoke, there by rendering

page_text: its expulsion from the flue more thorough and effectual, and of course greatly
improving the draft.
Having thus described the Invention that has been communicated to me,
and having explained the principles thereof by which it may be distinguished
from others of the like character, I shall now proceed to point out such parts
thereof as I claim therein. I claim the method herein above explained of
creating a draft in flues or furnaces, (that is to say,) by arranging in the dis-
charging flue or chimney of the furnace a chamber or air receiver B, B, into
which air is forced by means of a blowing apparatus, and is discharged
therefrom through suitable apertures formed in its top or other proper part
thereof, the whole being constructed and operating substantially in the manner
and for the purposes as herein above set forth. And I also claim arranging
the discharging apertures of the chamber B, B, in helical or curved directions,
for the purpose of creating a rotating or whirling movement of the air expelled
from the chamber into the chimney in order to improve the draft thereof, as
herein-before set forth and described.
In witness whereof, I, the said John Tappan, have hereunto set my hand
and seal, this Twenty-second day of September, in the year of our
AND BE IT REMEMBERED, that on the Twenty-second day of Sep-
tember, in the seventh year of the reign of Her Majesty Queen Victoria, the
said John Tappan came before our said Lady the Queen in Her Chancery, and
acknowledged the Instrument aforesaid, and all and everything therein con-
tained and specified, in form above written. And also the Instrument aforesaid
was stamped according to the tenor of the Statute made in the fifty-fifth year
of the reign of His late Majesty King George the Third.