AN IMPROVED COWL FOR PREVENTING DOWNWARD DRAUGHTS IN CHIMNEYS
Year: 1875

page_text: LETTERS PATENT to John Catherall, of the Borough and County of
Newcastle-upon-Tyne, Builder, for the Invention of "AN IMPROVED
COWL FOR PREVENTING DOWNWARD DRAUGHTS IN CHIMNEYS.
PROVISIONAL SPECIFICATION left by the said John Catherall at the
Office of the Commissioners of Patents, with his Petition, on the
27th April 1875.
I, JOHN CATHERALL, of the Borough and County of Newcastle-upon-
Tyne, Builder, do hereby declare the nature of the said Invention for
"AN IMPROVED COWL FOR PREVENTING DOWNWARD DRAUGHTS IN CHIMNEYS," to
be as follows :—
I form my improved cowl of two straight tubes of ordinary size for
such purpose. One tube revolves horizontally on a pivot over the other
which stands vertical when placed over the chimney pot or flue as is
generally the case. Into the windward end of the horizontal tube I
insert a funnel or hollow cone, the wide mouth of which is of the same

page_text: diameter as the tube; the smaller end of the funnel being within opens
over or near the centre of the vertical tube. The wide mouth of the
funnel is kept towards the wind by the usual means of a vane, it is
therefore evident that the wide mouth of the funnel being always turned
by the vane towards the wind causes the wind to enter thercin, and
passing rapidly through the narrow outlet produces a vacuum over the
vertical tube up which the air or smoke from below rises at once to
fill.
SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said John Catherall in the Great Seal Patent Office on
the 27th October 1875.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, JOHN
CATHERALL, of the Borough and County of Newcastle-upon-Tyne,
Builder, sond greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her Letters
Patent, bearing date the Twenty-seventh day of April, in the year of
our Lord One thousand eight hundred and seventy-five, in the thirty-
oighth year of Her reign, did for Herself, Her heirs and successors,
give and grant unto me, the said John Catherall, Her special licence
that I, the said John Catherall, my executors, administrators, and
assigns, or such others as I, the said John Catherall, my exccutors,
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, usc, exercise, and
vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "AN IMPROVED COWL
FOR PREVENTING DOWNWARD DRAUGHTS IN CHIMNEYS," upon the condition
(amongst others) that I, the said John Catherall, my executors or ad-
ministrators, 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.

page_text: NOW KNOW YE, that I, the said John Catherall, do hereby declare
the nature of my said Invention, and in what manner the same is to
be performed, to be particularly described and ascertained in and by the
following statement in writing, reference being had to the Drawing
hereunto annexed, and to the letters and figures marked thereon (that is
to say) :-
My improved cowl is formed of two straight tubes of the size ordinarily
used for such purposes. One of the tubes is placed vertically over the
chimey pot or flue, and the other so made as to revolve horizontally over
it. The horizontally revolving tube is so balanced and directed by a
vane that one end only shall turn toward the wind as is often the casc,
but in the windward end of the tube I fix a funnel, the wide mouth of
which is of the same diameter as the tube, and the smaller end being
within opens over or beyond the centre of the vertical tube; con-
sequently the wind enters the funnel, and passing rapidly through the
narrow outlet tends to produce a vacuum behind, causing the smoke to
risc up and be carried forward by the wind that enters an opening mado
under the rim of the funnel for that purpose.
In the accompanying Drawing I have shewn in Figure 1 a sectional
clevation of my improved cowl, wherein A is the vertical tube fitted
over the chimney pot or flue; B is the horizontally revolving tube made
with a junction piece A¹ which revolves with it; C is the funnel fitted
in the windward end of the tube B; and D, the funnel pipe to direct
the stream of air. E is an opening or louvre made in the junction pieco
under the rim of the funnel, so that when the smoke rises to fill the
partial vacuum caused by the rush of air through the funnel pipe it is
driven outward by the current of air from the louvre E; F is an ordinary
vanc to keep the wide mouth of the funnel and the louvre always
towards the wind; G, the pivot pin around which the tube B revolves;
H, H, are stays to support the pivot pin; and h is a block or piece of
glass to receive the point or end of the pivot which reduces the friction
to a minimum. I have found that the introduction of this piece of
glass entirely dispenses with the use of oil or other lubricant, and renders
thic vane susceptible to the slightest variation in the direction of the
wind.
My improved cowl may be also adapted and used for other purposes
beside the cure of smoky chimneys and downward draughts, and in
Figure 2 I have shewn it modified for ventilating railway carriages; in

page_text: this Figure a is the body of the ventilator fastened by the flange to the
roof of the carriage. The upper part a* has a hinge i and fastener / to
allow the lamp that lights the interior of the carriage being taken out
and trimmed. c is the funnel; and d, the funnel pipe; b is the hori-
zontal tube with the junction piece a²; f is the vane to keep the funnel 5
facing toward the direction the train is proceeding.
ordinary ventilator; in this case
My cowl may also be used as an
nothing is required when the cowl is fixed on the roof but to make a
shaft or tube communicate from the room or building to the upright
tube A, Figure 1. The opening or louvre E may then be dispensed
with, and the vitiated air from the building will at once rise to fill the
vacuum produced by the wind rushing through the funnel pipe D.
Having now described my said Invention, and in what manner the
same may be carried into effect, I claim the fitting and fixing the
funnel C and funnel pipe D in the windward end of a cowl used cither
as a cure for smoky chimneys and downward draughts, or
ventilator.
as a
In witness whereof I, the said John Catherall, have hereunto set
my hand and scal, this Twenty-sixth day of October, in the
your of our Lord One thousand eight hundred and seventy-
fivc.