IMPROVEMENTS IN DOWNCAST VENTILATING COWLS, APPLICABLE FOR SHIPS.”
Year: 1881

page_text: LETTERS PATENT to John Walter Gibbs, trading as John Gibbs and Son,
of 27, South John Street, Liverpool, in the County of Lancaster, Ventilating.
Engineer, for an Invention of "IMPROVEMENTS IN DOWNCAST VENTILATING
COWLS, APPLICABLE FOR SHIPS.”
PROVISIONAL SPECIFICATION left by the said John Walter Gibbs at the
Office of the Commissioners of Patents on the 13th August 1881.
JOHN WALTER GIBBS, trading as John Gibbs and Son, of 27, South John Street,
Liverpool, in the County of Lancaster, Ventilating Engineer. "IMPROVEMENTS
IN DOWNCAST VENTILATING COWLS, APPLICABLE FOR SHIPS."
Ships down draught ventilating cowls as now used have in bad weather to be
taken off and the holes plugged to prevent them shipping seas. Now my Invention
is designed with the object of forming a cowl that shall be practically wave and
spray proof while catching and down casting the air. I make the cowl with the
shaft projecting upward into the cowl some distance and then continued on the
external side in the form of an angular, semicircular, conical, or other shield
extending to the top of the cowl. Further, I make the back of the cowl with a
deflecting plate, projection, or cone, so arranged as to deflect the air into the shaft.
When a sea strikes my ventilating cowl the water projecting forward strikes the
rear plate of the cowl, is deflected, and falls, running out at the bottom of the
cowl round the shaft; the air having no other escape goes into and down the shaft.
In thus describing my cowl I have described it in its simplest, and what I
consider its best form, but it is obvious that a cowl could be fitted up with baffle
plates, mechanical equivalents of the whole or parts of my prolonged shaft to
accomplish the same result, and in place of the shaft projecting into the cowl, the
cowl could be sunk all round it, when with the aforesaid baffle plates, the same
result would accrue, though perhaps not to so useful an extent.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said John Walter Gibbs in the Great Seal Patent Office on the 13th
February 1882.
JOHN WALTER GIBBS, trading as John Gibbs and Son, of 27, South John Street,
Liverpool, in the County of Lancaster, Ventilating Engineer.
"IMPROVEMENTS
IN DOWNCAST VENTILATING COWLS, APPLICABLE FOR SHIPS."
Ships down draught ventilating cowls as now used have in bad weather to be
taken off and the holes plugged to prevent them shipping seas. Now my Invention
is designed with the object of forming a cowl that shall be practically wave and
spray proof, while catching and down-casting the air. I make the cowl with the
shaft projecting upward into the cowl some distance, and then continued on the
external side in the form of an angular, semi-circular, conical, or other shield
extending to the top of the cowl. Further, I make the back of the cowl with a
deflecting plate, projection, or cone, so arranged as to deflect the air into the shaft.
When a sea strikes my ventilating cowl the water projecting forward strikes the
rear plate of the cowl, is deflected, and falls, running out at the bottom of the
cowl round the shaft; the air having no other escape goes into and down
the shaft.
Particulars of the Drawings:-Fig. 1 is a section on line a, a, of Fig. 3; Figs. 2
and 3 are front and side elevations shewing part section in dotted lines of my
downcast ventilator in its simplest form. A, elongation or continuation of main
shaft forming first baffle plate; B (Fig. 3) space cut out of said continuation or
elongation; C, shaft continued up at rear of cowl to prevent entrance of surplus
water into main shaft; D, deflecting or baffling plate, causing the air to strike
down the shaft instead of circling round the cowl, as indicated by direction of the
BITOWS.
Sometimes it is desired that a cowl should be permanently fixed, and not made
to swivel round on the shaft. In such case three or more cowls have to be
combined in one, and in such instance some necessary modifications are required,
as the various shafts passing through the cowls have to be combined in one below,
so must be placed moderately far back, and thus quite sufficient room is not left to
accomodate a large splash of water, such as that of a wave breaking over the
vessel. Figs. 4 and 5 shew my cowl modified to suit these conditions, in which
the main shaft A is divided into three A¹, A¹, A¹, above. These continue upward,
and are partially cut away at back at B, as in a single cowl, and there is the same
deflector D. Owing however to the smaller space behind these shafts, a heavy
splash of water will cause some to enter the shafts A¹, A1, A¹. I accordingly
place a subsidiary deflector F of greater diameter than the main shaft A to prevent
any of the water falling into the latter. The shaft A too is brought up as before
entire to some distance, say, three or four inches above the bottom plate, forming
a projecting rim, as shown at G, so that the water shed by the bevelled baffle
plate F can run round it and out through holes I.
The tubes A¹, A¹, A¹, are preferably made to taper in such a form as to give
better access to the air while still excluding the water; this is shown well in
Fig. 4. K, division plates; L, false top to secure sound construction of ventilator;
M, brushing plates secured to the division plates, so as to form each division more
nearly into a bell shape.
Having now described my Invention, and the two best ways known to me of
carrying it into effect, I claim as the Invention secured to me by Letters Patent,
1st. The single cowl ventilator, substantially as set forth in Figs. 1 to 3, con-
sisting of a cowl with a shaft running up through it, and partially cut away at

page_text: the back at such a height above the bottom as to prevent the water striking into
it, and the baffle plate or its mechanical equivalent at the back to deflect the air
down the shaft.
2nd. In a composite cowl, that is, of a cowl consisting of more than one division,
the combination of the independent shafts A' passing up through the cowl and
open in the upper portion at back with the single shaft A, so arranged that while
the air from the independent shafts can freely enter it any drip that may come
down the independent shafts shall be deflected away from the main shaft.
3rd. In a composite cowl, the back deflectors D and bottom deflector F, or their
mechanical equivalents, in combination with shafts, such as A', A', A', and A
projecting up through their respective floor plates (such as K), as centre tubes for
a short distance, thus preventing any water collecting or falling on the floor plates
from passing into the shaft.
4th. The general arrangement and construction of ventilating cowl, substantially
as described in the second part of this Specification, and as set forth in Figs. 4
and 5.
In witness whereof, I, the said John Walter Gibbs, have hereunto set my hand
and seal, this Eleventh day of February, in the year of our Lord One
thousand eight hundred and eighty twe