IMPROVEMENTS IN APPARATUS FOR INCREASING THE DRAFT OF CHIMNEYS AND FOR OTHER PURPOSES
Year: 1878

page_text: LETTERS PATENT to Francis Macdonald Robertson, of Croydon, in the County
of Surrey, Gentleman, and John Joyce, of Edmonton, in the County of
Middlesex, Mechanical Engineer, for the Invention of "IMPROVEMENTS IN
APPARATUS FOR INCREASING THE DRAFT OF CHIMNEYS AND FOR OTHER
PURPOSES."
Sealed the 28th January 1879, and dated the 30th July 1878.
PROVISIONAL SPECIFICATION left by the said Francis Macdonald Robertson
and John Joyce at the Office of the Commissioners of Patents on the 30th
July 1878.
FRANCIS MACDONALD ROBERTSON, of Croydon, in the County of Surrey, Gentle-
man, and JOHN JOYCE, of Edmonton, in the County of Middlesex, Mechanical
Engineer. "IMPROVEMENTS IN APPARATUS FOR INCREASING THE DRAFT OF
CHIMNEYS AND FOR OTHER PURPOSES."
This Invention consists in the construction of apparatus whereby the draught in
chimneys is greatly increased, thus preventing a downward current of air and the
consequent descent of smoke and other products of combustion, such apparatus
being also applicable to ventilating purposes.
The apparatus or cowl which constitutes this Invention is of a cylindrical form,
and is so mounted on the chimney head as to admit of its being caused to rotate by
the action of the wind, as will be well understood.
Around the vertical cylindrical portion of the cowl is formed or attached a
circular chamber, which is closed at its upper and lower ends, and is provided with
an opening or aperture at one side thereof.
That portion of the cowl which is so covered by the circular chamber is divided
horizontally by circular orifices, the intermediate portions being supported by means
of stays, as will be well understood. The edges of the said circular orifices are
provided with rims or flanges projecting in an upward direction towards the centre
of the cowl.

page_text: The upper end of the cowl, which is, by preference, turned at right angles to the
main portion, is made to resemble a trumpet mouth in order to facilitate the escape
of the products of combustion.
The cowl is provided with a vane so placed that the opening in the circular
chamber is always presented to the wind, whilst the exit opening faces in the
opposite direction.
The lower portion of the apparatus, which is in close proximity with the fixed
part of the chimney head, is provided with a flange which projects into a circular
channel or gutter attached to the said fixed part of the chimney head. The said
channel or gutter may be filled with glycerine or other non-corrosive fluid or fluids
in order to render the joint air-tight.
The action of the apparatus is as follows:-The wind acting on the vane causes
the cowl to assume such a position that the opening in the circular chamber faces
the wind, and the current of air passing through the same circulates in the annular
space forming the circular chamber, and passing through the circular orifices before
mentioned strikes against the projecting rims or flanges, and is thereby caused to
pass in an upward direction towards the exit aperture, carrying with it the products
of combustion, and producing an upward draught through the whole chimney.
Instead of the upper portion and exit opening being at right angles to the main
body of the cowl, as before described, the same may form a vertical cylindrical
continuation of the latter, and in this case the top, which is open, is protected from
the wind and rain by a cover or cap in such a manner as to allow of the escape of
the smoke and other products of combustion.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said Francis Macdonald Robertson and John Joyce in the Great Seal
Patent Office on the 30th January 1879.
FRANCIS MACDONALD ROBERTSON, of Croydon, in the County of Surrey, Gentle-
man, and JOHN JOYCE, of Edmonton, in the County of Middlesex, Mechanical
Engineer. "IMPROVEMENTS IN APPARATUS FOR INCREASING THE DRAFT OF
CHIMNEYS AND FOR OTHER PURPOSES."
Our said Invention consists in the construction of apparatus whereby the draught
in chimneys is greatly increased, thus preventing a downward current of air and
the consequent descent of smoke and other products of combustion, such apparatus
being also applicable to ventilating purposes.
The apparatus or cowl which constitutes our said Invention is of a cylindrical
form, and is so mounted on the chimney head as to admit of its being caused to
rotate by the action of the wind, as will be well understood.
Around the vertical cylindrical portion of the cowl is formed or attached a
circular chamber, which is closed at its upper and lower ends, and is provided with
an opening or aperture on one side thereof.
That portion of the cowl which is so surrounded by the circular chamber is
divided horizontally by circular orifices, the intermediate portions being supported
by means of stays, as will be well understood. The edges of the said circular
orifices are provided with rims or flanges projecting in an upward direction towards
the centre of the cowl. Or the said flanges are made to project outwards in a
downward direction in such a manner that the outer edges thereof meet and are
secured to the cylindrical cover of the circular chamber; the said flanges together
with the respective intermediate portions of the cowl above mentioned thus form a
series of rings within the said chamber, as will be readily understood by reference
to the annexed Drawings.
The upper end of the cowl, which is, by preference, turned at right angles to the
main portion, is made to resemble a trumpet mouth in or to facilitate the escape
of the products of combustion.
The cowl is provided with a vane so placed that the opening in the circular
chamber is always presented to the wind, whilst the exit opening faces in the
opposite direction.
The lower portion of the cowl, which is in close proximity with the fixed part of
the chimney head, is so constructed that while permitting the free rotation of the
cowl the joint is made so as to be as air-tight as possible.
We will now proceed to refer to the annexed Drawings, from which the nature
of our said Invention will be more clearly understood.
The same letters of reference indicate similar parts in the several Figures.
Figure 1 is a vertical section of the cowl and chimney head.
Figure 2 is an elevation shewing the opening in the circular chamber.
And Figure 3 is an end view.
A is the cowl; B, the chimney head; C is the rod or spindle on which A revolves,
and c are supports for the same; D is the circular chamber, and d the opening
therein; E, the portions of the cowl between the orifices; e, the rims or flanges;
F is the opening for the escape of the smoke.
The action of the apparatus is as follows:-The wind acting on the vane causes
the cowl to assume such a position that the opening d in the circular chamber D
faces the wind, and the current of air passing through the same circulates in the
annular space or spaces forming the circular chamber and striking against the
flanges e is deflected in an upward direction through the orifices between E and
towards the exit aperture F, carrying with it the products of combustion and
producing an upward draught through the whole chimney.
Instead of the upper portion and exit opening being at right angles to the main
body of the cowl, as before described, the same may form a vertical cylindrical

page_text: continuation of the latter, and in this case the top, which is open, is protected from
the wind and rain by a cover or cap in such a manner as to allow of the escape of
the smoke and other products of combustion.
Having thus described and ascertained the nature of our said Invention, and the
manner in which the same is to be performed, we would observe in conclusion that
what we consider novel and original, and therefore claim as constituting the Inven-
tion secured to us by the said herein-before in part recited Letters Patent is, the
combination and arrangement of the circular chamber and flanges in connection
with cowls, substantially as and for the purposes herein-before described and set
forth.
In witness whereof, we, the said Francis Macdonald Robertson and John Joyce,
have hereunto set our hands and seals, this Twenty-ninth day of January,
in the year of our Lord One thousand eight hundred and seventy-nine.