An Improved Chimney Cowl and Ventilator.
Year: 1886

page_text: Date of Application, 30th Mar., 1886.
Complete Left, 28th Dec., 1886.
Complete Accepted, 28th Jan., 1887.
An Improved Chimney Cowl and Ventilator.
I, JOHN ANDREW SHARP, of 3 Stevens Crescent, Totterdown, in the City and County
of Bristol, Engineer and Surveyor, do hereby declare the nature of this invention to
be as follows:-
The improved cowl to which this invention relates consists of a trumpet-shaped
funnel designed to be fitted at the small end in a chimney and surmounted by a second
funnel approximately bell-shaped. The upper funnel is conveniently supported by
stays or ties attached to it and to the lower funnel. The mouth or widest part of the
upper funnel is opposed to that of the lower which preferably extends upwards to
above the bottom or lip of the upper funnel which overhangs it.
Currents or gusts of air entering below the lip of the upper funnel will impinge
upon the exterior of the upper part of the lower funnel and become diverted or
directed upwards to pass out at the orifice in the top or small end of the upper funnel.
A downward current or gust entering at the orifice in the top of the upper funnel will
in part pass out at the bottom of that funnel between it and the upper part of the
lower funnel, and the further descent of such part as passes into the lower funnel will
be impeded by the friction against the sides of the said funnel and by the counteracting
force of the up draught in the chimney.
The orifice in the upper end of the upper funnel should not exceed in area that in
the lower end of the lower funnel.
By the use of a cowl constructed as above described, the passage of a down
draught in a chimney is obviated, and smoke from a fire grate with which such
chimney connects cannot be thereby forced downwards.
A free passage for the up draught is maintained and ventilation is, in conséquence,
promoted for which purpose the cowl may, if desired, be separately used.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.

page_text: I, JOHN ANDREW SHARP, of 3, Stevens Crescent, Totterdown, in the city and county
of Bristol, engineer and surveyor, do hereby declare the nature of this invention, and
in what manner the same is to be performed, to be particularly described and
ascertained in and by the following statement :-
The improved chimney cowl and ventilator in which this invention consists is con-
structed as follows. Surmounting a trumpet-shaped funnel which constitutes the
lower member of the cowl is a second funnel in shape somewhat resembling a wide-
mouthed bell. The second or upper funnel is stayed to the first or lower funnel. The
funnels are arranged so that the mouth or widest part of the one is opposed to that of
the other and the lower funnel is extended up above the lip of the upper funnel which
overhangs it.
The cowl is fitted to a chimney or a ventilating shaft by connecting the lower end
of the lower funnel to such chimney or ventilating shaft.
Atmospheric currents entering below between the lower and upper funnels are
directed upwards to pass out by the orifice in the top or small end of the latter, and
currents entering at the said orifice pass in part directly out between the lips of the
upper and lower funnels, and the further descent of such part as does not directly so
pass out is impeded by the friction in the throat of the lower funnel and by the
opposing energy of the up draught from the chimney or shaft.
The orifice in the upper part or top of the upper funnel does not, by preference,
exceed in area that of the lower end of the lower funnel.
By the use of a cowl constructed as above described, the passage of a down draught
in a chimney is obviated, and smoke from a fire grate with which such chimney
connects cannot be thereby forced downwards.
Under a modification, additional funnels are employed and arranged in a manner
substantially similar to the arrangement of the funnels above mentioned.
Referring to the appended drawing, the figure shown represents a vertical section of
one form of the improved cowl in which this invention consists.
Surmounting the lower funnel a, and stayed thereto by stays b, is the upper funnel e
the mouth or widest part of which overlaps that of the funnel a.
The upper funnel c is furnished at the top with a corona e stayed thereto as shewn.
The cowl is affixed to the top of a chimney or ventilating shaft by cementing or
otherwise securing the lower end thereto.
Atmospheric currents entering between the funnels a and c where they overlap are
directed upwards to pass out at the orifice in the top or small end of the latter, and
currents entering at the said orifice in the top or small end of the funnel e pass in part
directly out between the lips of the funnels, and the further descent of such part as
does not directly so pass out is obstructed by the narrow part or throat of the funnel a
and by the opposing force of any up draught from the chimney or shaft.
By the use of a cowl constructed as above described, the passage of a down draught
in a chimney is obviated and smoke from a fire grate with which such chimney connects
cannot be thereby forced downwards.

page_text: By making the corona e in the form of a funnel and arranging it to overlap the
upper orifice of the funnel e, currents of air are further obstructed and diverted.
Having now particularly described and ascertained the nature of this invention, and
in what manner the same is to be performed, I declare that what I claim is :-
1. A chimney cowl for preventing "smoking" in fire grates, and applicable also as
a ventilator, consisting of a trumpet-shaped or conical funnel such as a the lower end
of which is affixed to the chimney or ventilating shaft, and which is surmounted by a
bell-shaped or conical funnel such as c, such funnels being so arranged that the mouths
or widest parts thereof are opposed to one another and so that the mouth of the lower
funnel is overlapped by that of the upper funnel surmounting it, substantially as
herein before described with reference to the appended drawing.
2. An improved chimney cowl and ventilator consisting of a lower funnel such as a
surmounted by funnels such as e and e, substantially as herein before described with
reference to the appended drawing, or surmounted by additional funnels, arranged in
a manner similar to that of the funnels aforesaid.
W. LLOYD WISE,
46, Lincoln's Inn Fields, London, W.C.,
Agent for the Applicant.