AN IMPROVED PROAL
Year: 1880

page_text: LETTERS PATENT to James Robert Dry, of 25, Oriental Street, East India
Road, in the County of Middlesex, for an Invention of "AN IMPROVED
PROVISIONAL SPECIFICATION left by the said James Robert Dry at the
Office of the Commissioners of Patents on the 27th October 1880.
JAMES ROBERT DRY, of 25, Oriental Street, East India Road, in the County of
Middlesex. "AN IMPROVED COWL."
The want of a cowl that would be certain in its action in preventing the return
of smoke down the shaft has been long felt.
The reason why most of the cowls hitherto manufactured have been ineffectual
is that the pipe and cowl above the brick shaft raises the temperature of the
surrounding medium, the cold air presses all round, condenses the smoke, and
retards its free exit. Again in a cowl made to act as a shade, the shade is an
impediment, and displaces the wind by separating it, and the natural tendency is
to meet and unite on the other side, forming an eddy over the outlet, often
descending the shaft, the cowl thus defeating its own object.
The novelty and worth of my cowl as an Invention will be readily understood
by reference to the annexed Drawing, of which Figure 1 is a front view, Figure 2
a vertical section, and Figure 3 a back view, in conjunction with the following
description.
The bell mouth a of the cowl has a cone 6 inserted in the centre, with a narrow
aperture c around its base d, and is made to face the wind by a vane e (which may
be placed on the top). The superficial contents of air on entering is much greater
than the ring outlet, and being compressed by the force in front, and not meeting
with any resistance escapes with force and rapidity; the centre line being a part
vacuum attracts the smoke and air to fill it up, no downward tendency can result,
and the smoke not being previously condensed is blown away on the lee side.
Should the zinc pipe from necessity rise much above the brickwork, I propose to
have two, one within the other, in. apart, to prevent radiation; it is simple,
inexpensive, and a natural law ensures it being effectual. A small cowl of this
kind with a scrow propeller (similar in shape to those used by steam ships) placed
within the pipe leading to the cowl would be admirably adapted for relieving the
smoke or foul air from railway carriages, and by a simple contrivance the inventor
will ensure the rain being excluded.
This cowl would be of great service for ventilating engine rooms in steam ships
or any part of the ship where ventilation is required; the propeller revolving one
way would extract foul air, and by reversing the propeller, it would furnish a large
supply of fresh air.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said James Robert Dry in the Great Seal Patent Office on the 27th
April 1881.
JAMES ROBERT DRY, of 25, Oriental Street, East India Road, in the County of
Middlesex. "AN IMPROVED COWL."
The want of a cowl that would be certain in its action in preventing the return
of smoke down the shaft has been long felt. The reason why most of the cowls
hitherto manufactured have been ineffectual is, that the pipe and cowl above the
brick shaft raises the temperature of the surrounding medium, the cold air presses
all round, condenses the smoke, and retards its free exit.
Again in a cowl made to act as a shade, the shade is an impediment, and displaces
the wind by separating it, and the natural tendency is to meet and unite on
the other side, forming an eddy over the outlet, often descending the shaft, the
cowl thus defeating its own object.
Now the object of this Invention is to obviate the before-mentioned disadvan-
tages, and it will be clearly understood on reference to the accompanying Drawings.
Figure 1 shows the improved cowl as applied to the cap of a cluster of chimnies
of an ordinary dwelling.
A hood a fits over and is secured to the brickwork b, terminating in a short
neck c, the whole serving to lead the smoke and gases from the mouths of the
chimnies d, d, to the cowl proper e which is pivotted, and can turn freely on the
stem or rod f, the latter being well steadied by the cross bar g, and firmly fixed at
its base on the brickwork at h.
The cowle has a bell-mouth i and a cone k inserted in its centre, with a narrow
aperture around the base m of the said cone, and an opening n opposite to it, the
bell mouth and cone being made to face the wind by the influence of the vane o on
the top.
In action the wind blows directly into the bell mouth i, and by the sloping sides
of the latter, in conjunction with those of the cone k, it is rapidly compressed and
caused to issue through the circular opening at a great velocity, and it leaves the
cowl through the opening n.
By the above action a part vacuum is formed at the base m of the cone k, which,
aided by the rapid velocity of the air passing through the cowl, causes a powerful
suction through the neck c, and attracts the smoke and ejects it at n, no down-
draught being possible.
Figure 2 is an outside view looking on to the apex of the cone k, also clearly
showing the annular opening and bell mouth i. The bell mouth and cone are
shown of circular form, but it is evident they may be of square, hexagonal, or other
outline in cross section, without impairing their efficiency.
The details of the construction and the action of the improved cowl having been
clearly set forth in the description of Figures 1 and 2, it will suffice to say that the
modification seen in Figure 3 shows its application for the purpose of ventilating a
railway carriage, and Figure 4 the form in which I prefer it for ventilating the
hold, cabin, decks, or stoke hole of, say, a merchant vessel, whilst Figure 5 shows
it applied to ventilate a large hall or public building, similar letters of reference
indicating similar parts in each Figure.
In Figure 3 the cowl is put in action by the rapid motion of the carriage, and
the air passing through the aperture 7, impinging on the vane wheel p, causes it to
rapidly rotate, and with it the screw q, which in conjunction with the air passing
through the cowl, draws all vitiated air out of the carriage through the branches 2,
and ejects it at the opening n. The cowl e rotates on the rod f, supported on the
bar g, and is caused to face the passing current of air by the vane o.

page_text: 8,
The stemt of the vane wheel p and screw q is stepped below in the bar and is
steadied at its top in the underside of the bar g, so that f and t are independent of
each other.
The cowl shown in Figure 4 is arranged to draw out foul air, or to drive in fresh
air, for which purpose it has a vane wheel p to rotate the screw q in one direction,
and another wheel u to drive it in the opposite direction as desired.
The cowl head has no vane, and the bell mouth i or opening n can be faced to
the wind by hand; if to extract hot or foul air, it is placed as shown, the wind
rotating the wheel u, consequently the screw 9 through an opening in the cowl
head, and assisting the air through the aperture 7; but if to send down fresh air,
the opening n is faced to the wind, when it rushes down the shaft w and rotates p
and in the opposite direction, which assist the action, the branches being lod
where necessary, so that they can exhaust or deliver where desired. The wheel u
during the latter operation revolves, but is inoperative through the shield v¹.
The cowl shown in Figure 5 is very similar in internal construction to that in
Figure 4, but the head e is pivotted, and the vane o causes the bell mouth to face
the wind when exhausting, the wind's direction being indicated by a pointer o
working over a dial at y. The pointer is put in motion through the toothed ring s
on the cowl head e acting on the gearing a, b¹ and c'.
d' is a second toothed ring on the head e; e¹, a toothed wheel on the sleeve f¹;
and gl, another wheel on the bottom of the sleeve, gearing into the wheel '; ', a
rack in guides which, by incans of the cords j, j', and hand wheel ¹, can be inade
to rotate ¹, and through g¹ and e¹ the cowl head.
When a down supply is required, a cord which passes over the pullies m', m',
is pulled; this rotates the toothed disc n' which lifts the sleeve f, and gears e¹
with a'.
The hand wheel k¹ being now turned draws the rack into gear with ', rotates
it, and through g' and el, causes the opening n to face the wind; this is indicated
by the pointer, the wheel k¹ being reversed draws the rack out of gear, and l'
being released, g¹ and e¹ and the cowl head are free. 21 is an ornamental centre
piece, behind which all the gearing may be placed, and q are small rollers fitted
to e, and rolling on the shaft w, to render the former lively in its action.
And having now described the nature of my said Invention, and in what manner
the same is to be performed, 1 declare that I claim,-
The improved cowl as described, and substantially as shown in the annexed
Drawings.
In witness whereof, I, the said James Robert Dry, have hereunto set my
hand and seal, this Twenty seventh day of April, One thousand eight
hundred and eighty one.
JAMES ROBT. DRY. (L.S.)