IMPROVEMENTS IN CHIMNEY Tops
Year: 1863

page_text: LETTERS PATENT to James Durrant, of Sussex Street, St. Pancras, in
the County of Middlesex, Engineer, for the Invention of "IMPROVEMENTS
IN CHIMNEY Tops."
Sealed the 15th August 1863, and dated the 17th February 1863.
PROVISIONAL SPECIFICATION left by the said James Durrant at the
Office of the Commissioners of Patents, with his Petition, on the
17th February 1863.
I, JAMES DURRANT, of Sussex Street, St. Pancras, in the County of
Middlesex, Engineer, do hereby declare the nature of the said Invention for
IMPROVEMENTS IN CHIMNEY TOPS," to be as follows:-
On the tapering can or top of a chimney I mount a six, eight, or other
sided figure of a slightly tapering form, the smaller end being uppermost; this
part, which I term the body, is much larger than the chimney top before
mentioned, which I will denominate the base, this base, however, I make no
longer than is conveniently necessary to reduce the square form of the flue
below to the round form at the upper part; the body part is down upon and
envelopes the base to about a third of its length, and is, by suitable bracket
pieces or stays, fixed securely thereto. At each of the angles of the body are
projecting radial leaves or plates extending to the whole height of the body;
these leaves I form hollow to allow the passage of air up the interior, and
being bent to the form and of the same sheet of metal give stiffness and
strength to the structure of the body. At the lower part of the body and

page_text: throughout the extent to which it envelopes the base I form openings of large
area, and fit thereto inclined surfaces which spring from the bottom and larger
diameter of the body, and are curved up to the smaller diameter near to the
upper end of the base. These openings are altogether below the top of base,
terminating a short distance below that point. The effect of wind striking
against sides of the body and entering these openings is to enter and drive
itself in an upward direction in the chimney top, creating an upward current
therein, and carrying the smoke with it out at the top. The radial leaves
before mentioned prevent the wind distributing itself sideways, and it is
therefore constrained to enter as described. A small space for air is provided
below the body, it passing up within the hollow leaves before mentioned and
between the inclined plates of the openings and the base. On the top of the
body I mount a conical top, having sides and radial leaves similar to the body,
the base of this conical top is as large as the diameter of the body at the
extreme of the radial leaves, and contracts at top to a smaller diameter than
the body, although only about one-third or one-fourth the height of the body.
The sides of this tapered piece I form of two flats instead of each being a flat
surface like the body, the angle being vertical midway between the leaves,
this makes the whole size of this tapered piece somewhat less, although at
same time embracing the leaves of the body. Above this tapered piece I
mount and fit in like manner a second tapered piece similarly formed, but
smaller in diameter and rather less taper; and above this again a plain
conical piece, by which the smoke escape aperture is reduced to the proper
size; each of these pieces lap a little the one on the other, and the effect
produced is this, that a great deal of the air striking against the sides of the
chimney top is confined by the radial leaves before described and constrained
to pass into the chimney top and take an upward direction therein and out at
the top, producing a draught therein and preventing wind blowing down the
chimney, therefore preventing down draught and curing what are termed
smoky chimnies. The radial leaves of the tapered pieces are made in same
manner as in the body, out of same sheet of metal, and hollow, to act as air
passages inside. Thus the wind caught between the radial leaves of the body
has a tendency to enter partly at the lower openings and partly under the
first taper piece, while the wind caught between the leaves of this taper piece
enters below the second taper piece, and the air caught between the leaves
of the upper piece enters below the small plain conical piece surrounding the
whole.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said James Durrant in the Great Seal Patent Office on the
17th August 1863.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JAMES
DURRANT, of Sussex Street, St. Pancras, in the County of Middlesex, Engineer,
send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Seventeenth day of February, in the year of our
Lord One thousand eight hundred and sixty-three, in the twenty-sixth year of
Her reign, did, for Herself, Her heirs and successors, give and grant unto me,
the said James Durrant, Her special licence that I, the said James
Durrant, my executors, administrators, and assigns, or such others as I, the
said James Durrant, my executors, administrators, and assigns, should at
any time agree with, and no others, from time to time and at all times
thereafter during the term therein expressed, should and lawfully might
make, use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Chanuel Islands, and Isle of Man, an Invention for "IM-
PROVEMENTS IN CHIMNEY TOPS," upon the condition (amongst others) that I, the
said James Durrant, my executors or administrators, by an instrument in
writing under my, or their, or one of their hands and seals, should particularly
describe and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the Great
Seal Patent Office within six calendar months next and immediately after the
date of the said Letters Patent.
NOW KNOW YE, that I, the said James Durrant, do hereby declare the
nature of my said Invention, and in what manner the same is to be per-
formed, to be particularly described and ascertained in and by the following
statement, reference being had to the Sheet of Drawings hereunto annexed,
and to the letters and figures marked thereon (that is to say):-
On the tapering can or top of a chimney I mount a six, eight, or other
sided figure of a slightly tapering form, the smaller end being uppermost; this
part, which I term the body, is much larger than the chimney top before
mentioned, which I will denominate the base; this base, however, I make
no longer than is conveniently necessary to reduce the square form of the
flue below to a round form at the upper part, the body part is down upon and
envelopes the base to about a third of its length, and is, by suitable bracket
pieces or stays, fixed securely thereto. At each of the angles of the body are
projecting radial leaves or plates extending to the whole height of the body;

page_text: these leaves I form hollow to allow the passage of air up the interior, and
being bent to the form of the same sheet of metal, give stiffness and strength
to the structure of the body. At the lower part of the body and throughout
the extent to which it envelopes the base I form openings of large area, and
fit thereto inclined surfaces which spring from the bottom and larger diameter
of the body, and are carried up to the smaller diameter near to the upper end
of the base. These openings are altogether below the top of the base, termi-
nating a short distance below that point. The effect of wind striking against
the sides of the body & entering these openings is to enter and drive itself
in an upward direction in the chimney top, creating an upward current therein,
and carrying the smoke with it out at the top. The radial leaves before
mentioned prevents the wind distributing itself sideways, and it is therefore
constrained to enter as described. A very small space for air is provided
below the body, it passing up within the hollow radial leaves before mentioned
and between the inclined plates of the openings and the base. On the top
of the body I mount a conical cap, having sides and radial leaves similar to
the body; the base of this conical top is as large as the diameter of the body
at the extreme of the radial leaves, and contracts at top to a smaller diameter
than the body, although only about one-third or one-fourth of the height of the
body. The sides of this tapered piece I form in two flats instead of each
being a flat surface like the body, the angle being vertical midway between
the leaves, this makes the whole size of this tapered piece somewhat less,
although at same time embracing the leaves of the body. Above this tapered
piece I mount and fit in like manner a second tapered piece similarly formed
but smaller in diameter; and above this again a plain conical piece, by which
the smoke escape aperture is reduced to the proper size, each of these pieces
lap a little the one on the other, and the effect produced is this, that a great
deal of the air striking against the sides of the chimney top is confined by the
radial leaves before described and constrained to pass into the chimney top
and take an upward direction therein and out at the top, producing upward
draught therein and preventing wind blowing down the chimney, therefore
preventing down draught and curing what are termed smoky chimnies,
The radial leaves of the tapered pieces are made in same manner as in the
body, out of the same sheet of metal, and hollow, to act as air passages inside.
Thus the wind caught between the radial leaves of the body has a tendency to
enter partly at the lower openings and partly under the first taper piece,
while the wind caught between the leaves of the upper pieces enters below
the small plain conical piece surmounting the whole,

page_text: DESCRIPTION OF DRAWINGS.
Fig. 1 represents a side elevation of a chimney top constructed according
to my Invention; Fig. 2 represents a central vertical section, and Fig. 3 a
plan of the same, while Fig. 4 represents a horizontal section taken on
line 1, 2, Fig. 1. This chimney top is made of zinc or other suitable
material.
A, A, is the base-piece furnished with a flanch at bottom as usual to build
and fix it on the chimney stack, to the opening in which it is suitably adapted;
on base A the body B, B, is mounted and fixed by suitable brackets c, c; the
body B is made of one or more pieces of metal bent to the form shown in the
horizontal section so as to produce six, eight, or other number of radial
projections d, d, at the angles formed by the several sides w, w. These radial
projections form internal air channels, and externally confine the air pressing
against the sides w, and tend to direct it in an upward direction. In the
lower part of the sides of the body are openings e, e, admitting the wind to
inclined shoots f, which form the connection between the body B and the
base A, and at same time unite with the channels g, g, inside the radial
projections d, providing for the ingress of air at bottom of those channels, the
whole of the parts being suitably soldered or otherwise fixed together; H is a
truncated conical piece formed with radial leaves i of one and the same sheet
of metal bent to the form required, the form of the sheet or piece must be cut
of a curved form, as well understood in cutting shades and other conical
forms: In this conical piece instead of flats between the radial leaves i, as in
the body, I form them of two surfaces x, x, inclined to each other, as seen
in Figs. 1 and 3, the apices of the angles being adapted to receive and
embrace the extreme diameter of the leaves d, d, of the body, at which points
the cone is suitably fixed thereto. K is the second conical piece made in
same manner as cone piece H previously described, with flat surfaces y and
radial projections I, and secured at the apices of the angles between the flat
surfaces y, y, to the extreme diameter of the radial leaves i of H. The whole
is surmounted by a plain conical piece L, to form a suitable finish to the
chimney top, or it may be otherwise surmounted and ornamented. The effect
of flat surfaces w, x, and y, of the body B, and fluted conical parts H and K,
on the wind striking them is that the air has a tendency to confinement
between the radial leaves or projections d, i, & l, and the only ready escape
being upwards by reason of the inclination of the several surfaces, it is carried
with more or less force in an upward direction into the chimney can, and

page_text: thence out at the top, carrying with it the smoke and having a tendency to
increase the draught in the chimney and to prevent down draught.
Having described the nature of my Invention and the manner of performing
the same, I declare that what I claim as my Invention to be protected by the
herein-before in part recited Letters Patent is, the combination and arrange-
ments of parts constituting a chimney top or can, as herein-before described
and represented in the Drawings annexed.
In witness whereof, I, the said James Durrant, have hereunto set my
hand and seal, this Fifteenth day of August, in the year of our Lord
One thousand eight hundred and sixty-three.
JAMES DURRANT. (L.S.)