AN IMPROVED CAP DESIGNED FOR INCREASING THE UPWARD DRA OF CHIMNEYS, AND FOR VENTILATING SHIPS AND BUILDINGS
Year: 1864

page_text: LETTERS PATENT to Thomas Brown, of No. 4, Dagmar Road, South
Hackney, in the County of Middlesex, Engineer, for the Invention of
"AN IMPROVED CAP DESIGNED FOR INCREASING THE UPWARD DRAFT OF
Sealed the 10th March 1865, and dated the 6th October 1864.
PROVISIONAL SPECIFICATION left by the said Thomas Brown at the
Office of the Commissioners of Patents, with his Petition, on the 6th
October 1864.
I, THOMAS BROWN, of No. 4, Dagmar Road, South Hackney, in the
County of Middlesex, Engineer, do hereby declare the nature of said
Invention for "AN IMPROVED CAP DESIGNED FOR INCREASING THE UPWARD DRAFT
OF CHIMNEYS, AND FOR VENTILATING SHIPS AND BUILDINGS."
My Invention consists in forming a chimney cap or ventilator of two cap-
pieces of a pyramidal, conical, or other convenient form, and which, being chiefly
designed for chimneys, from its peculiar shape I denominate the "pagoda
chimney cap or cowl."
The inner cap-piece is closed at the top, and varies in size as may be
required. In the sides of this cap-piece are a number of narrow. apertures for
the egress of the smoke; the area of these apertures should be about the
area of the opening at the top of the chimney. If the cap be pyramidal
four of these apertures will be found sufficient, and these should be located:
rather above the centre. line of the pyramid. The base of this cap overlaps

page_text: the chimney, or the aperture when applied to ventilating ships and buildings.
The outer cap-piece is open at the top, and is placed over the inner one, and
covers the said apertures. Between these cap-pieces however is a space
-round the sides, which may vary-in-width_according to the size of the chimney,
the two cap-pieces being secured together by simple stays or other convenient-
means.
The most suitable materials for the construction of this cap or cowl are
metals or pottery, and said cap or cowl may be fixed in its position in any
convenient manner.
For ships, galleys, and stove pipes this Invention will be found invaluable.
In addition to its preventing -a-downward draft. in smoke pipes or chimneys,
it greatly assists in creating an upward draft and in ventilating structures.
The Invention is remarkably simple and durable, and cannot from its
nature get out of order. It is alike effective and inexpensive; it is scientific
in construction, and ornamental in design. By its use chimney pots may be
dispensed with, and it' may be made of sufficient length to cover a series of
chimney flues.
SPECIFICATION in pursuance of the conditions of the Letters Patent, filed
by the said Thomas Brown in the Great Seal Patent Office on the
5th April 1865..
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, THOMAS
BROWN, of No. 4, Dagmar Road, South Hackney, in the County of Mid-
dlesex, Engineer, send greeting.
**
WHEREAS Her most Excellenti Majesty Queen Victoria by Her Letters
Patent, bearing date the Sixth-day of October, in the year of our Lord
One thousand eight hundred and sixty-four, in the twenty-eighth year of
Her reign, did; for Herself, Her heirs and successors, give, and grant unto
me, the said Thomas Brown; Her special licence, that I, the said Thomas
Brown, my executors; administrators, and assigns, or such others as I, the
said Thomas Brown, my executors, administrators, and assigns, should at
any time agree with, and no. others, from time to time and at all times.tliere-
after during the term therein expressed, should and lawfully, might, make,
use, exercise, and vend; within the United Kingdom of Great Britain and
Ireland, the Channel Islands; and Isle of Man, an Invention for "AN IM-
PROVED CAP DESIGNED FOR INCREASING THE UPWARD' DRAFT OF CHIMNEYS,, AND FOR
VENTILATING SHIPS AND BUILDINGS," upon the condition (amongst others) that
.

page_text: 1, the said, Thomas Brown, my executors or administrators, by an instrument
in writing, under my, or their, or one of their hands and seals, should par-
ticularly 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.
NOW KNOW YE, that J, the said Thomas Brown, do hereby declaro
the nature of the said Invention, and in what manner the same is to be
performed, to be particularly described and ascertained in and by the follow-
ing statement, reference being had to the accompanying Sheet of Drawings
making, a part of this Specification.
The nature of said Invention consists in forming a chimney cap or venti-
lator, of a pyramidal, conical, or other convenient shape by the peculiar.
construction and arrangement of two or more cap-pieces, and which apparatus
by reason of its uses, and from its peculiar form of construction, I denominate
"the pagoda chimney cap or ventilator."
DESCRIPTION OF THE DRAWINGS.
Figure 1 is a vertical section of the apparatus; Figure 2, a plan of the
same.
Figure 3 is a plan of the inner or bottom cap-piece detached..
Figure 4 is a plan of the outer or top cap-piece.detached.
Figure 5 shows the apparatus, of different forms applied.as a chimney cap.
Figure 6 shows the apparatus of different forms applied as a ventilator.
Figure 7 shows the apparatus applied both as a ventilator and a chimney
cap.
Figure 8 shows the apparatus, applied to the top and sides of a railway
carriage as a ventilator.
Figure 9 shows the apparatus as applied to a ship both as a ventilator and
a chimney cap. Like, letters refer to corresponding parts in the several
Figures.
Though the Invention is shown variously applied and modified in form
according to the situation and circumstances of each case, the distinctive
features are the same in all the applications.. Other modifications and appli-
cations may be made for the purpose of ventilation, and. determining the
current in one particular direction, which may be found advantageous
according to the principles berein-after set forth and illustrated.
The apparatus may be constructed of any suitable material, such, for
instance, as-metal, pottery, or slate.

page_text: The inner or bottom cap-piece A, shown detached in Figure 3, and forming
part of the chimney cap or ventilator B, is closed at the top. The size of this
cap-piece is governed by the size of the flue when the apparatus is used as
a chimney cap, and when used as a ventilator-by-the-dimensions of the aper-
ture over which the apparatus is to be placed. The base of this cap-piece
should be sufficiently large to cover the aperture or apertures, and may for
ornamentation when the apparatus is used as a chimney cap project beyond
the sides of the chimney or chimneys, and for convenience when the apparatus
is used as a ventilator beyond the edge surrounding the opening. This 'cap-
piece may be formed of one or more plates in any convenient manner, the
number of plates or pieces, and the mode of manufacture that may be advan-
tageously employed; depending principally upon the character of the material.
The sides of cap-piece A are shown with an inclination of about forty-five
degrees, which inclination is preferred, but this may be considerably varied, as
seen in some of the Drawings, without essentially impairing the efficiency of
the apparatus, which depends on the deflection or reflection of the current of
the atmosphere either meeting with or impinging against the outer inclined
surface of the inner cap. One or more apertures a, Figures 1 and 3, are
formed in each side of the cap-piece A. The position and shape of these
apertures may be varied, but the aggregate area of these openings should
not be less than the minimum section of the chimney pot or throat of the
chimney. The plates forming the sides of this cap-piece when the apparatus
is designed for a chimney cap are made level in the planes of their inclination,
bringing the upper and lower edges of the apertures a in a line with the sur-
faces of said plates. To obtain the most beneficial effect on smoky chimneys
it will be necessary to extend outward the upper edge surrounding the aper-
ture a quite as far as the lower, and in case of ventilation, in order to
prevent water from passing through the aperture a, the upper edge may
project, which, latter form of construction is illustrated in Figures 6 and 7.
The area of the apertures a will vary with the sectional area of the flue'or
flues over which the chimney cap B is placed, and to ensure the most beneficial
effect the aggregate of these apertures should be as above stated. The
ascending smoke passes through these apertures, the apparatus being so placed
on the chimney's b, 1,6", Figure 5, or if desired on a chimney pot c, Figure 7,
that all other outlets for the smoke are closed. The vitiated air, or smoke
and dust in case of foundries and machine shops, rising, passes through these
apertures when the apparatus is used as a ventilator, other apertures for egress
being closed.
The outer or upper cap-piece C, clearly shown in Figures 1, 2, and 4, is

page_text: open at the top. The number of sides, their inclination, and the size of this
cap-piece correspond with those of the inner cap-piece A, over which is
placed, and to which it is attached by means of connecting rods or stays d, or
the two cap-pieces, may be united by ribs extending along the angles, or in
any other suitable and convenient manner. The cap-piece C extends above
and below the apertures a, as shown in Figure 1, leaving a space e between
the two cap-pieces for the passage of the current of air which enters between
the stays, ribs, or other connections at the top or bottom of the space, and
for the egress of smoke or vitiated air in either direction. The space e may
vary in width according to the size of the apertures a. The sectional area of
this space for a chimney of any given dimensions may be considerably varied
without essentially affecting the efficiency of the apparatus, and if equal to the
aggregate of the apertures a will be sufficient. The required size of the
opening hat the top of the cap-piece C will necessarily be governed by the
width of the space é and the relative position of the two cap-pieces A and C,
or the sectional area of the space e taken at right angles to the inclined'
surface of the cap-pieces. Instead of a cap-pièce C formed of one plate or
plates united as shown, separate plates covering each aperture a may be
employed with an open space at each angle of the apparatus. The method
illustrated is however preferable for its cheapness, durability, and efficiency.
These chimney caps or ventilators may be secured in position in any suitable
and convenient manner. In some instances a hinge, clasp, or bolt and nut
may be used with advantage. What may be the best mode in any given case
will depend chiefly upon the character of the material of which the apparatus*
is formed, whether metal, pottery, slate, or other substance, and upon the
character of the object upon which it is designed to be placed.
The application of this apparatus as a chimney cap only is illustrated in
Figure 5, but with modifications in form to adapt. the same to different con-
ditions. The cap B of the ordinary construction is placed upon a single
chimney b.. A cap of similar construction enlarged is placed at the top of off
the building over several chimneys or flues 6', and a cap modified in form to
adapt the same for application to one of several flues or chimney pots in juxta-
position is placed upon the chimney 6".
The application of the apparatus as a ventilator only is illustrated in
Figure 6. The ventilator is shown placed upon the top of a brewery," the
principle of construction being the same as that shown in Figure 1, though'
somewhat modified in form. Under the lower edge of the ventilator
formed an aperture k in the base or wall sustaining the ventilator to assist in
the ventilation. A. ventilator of similar construction is applied horizontally
may be

page_text: over the windows-m, and may be thus applied. to other portions of the sides of
the building. In this Figure the ventilators are also shown applied to street
and other lamps n for the purpose of creating an, upward draft, and thereby
-increasing the brilliancy of the flame...
The applications of the apparatus: as. a ventilator and chimney cap-are-
"illustrated in Figure 7. The ventilator, of somewhat different construction to
that shown in Figure 6, is placed over the top of a public building. In this
application two apertures a are shewn in each side of the apparatus. The
chimney cap is applied indirectly to the chimney by being fixed to the ordinary
chimney; pot; c.
The application to the, sides: and, top of a railway carriage, of the apparatus
as a ventilator is illustrated in Figure 8., These ventilators may also be
advantageously, applied; in the same manner to the ends of railway carriages
The form of construction is similar to that heretofore; described.
The applications of this apparatus to a ship, as a ventilator and chimney
cap are illustrated in Figure 9. The ventilators are applied over the forward.
hatchway, engine, room; and after. saloon; and the chimney caps over the smoke
pipes F.
1
The peculiar construction of this, chimney cap or ventilator prevents an
external current, of air passing through the apertures a in whichever direc
tion the same is: moving, and always secures an unopposed passage, of the
smoke, dust, or, vitiated air either, up or down, the space, e-between the two,
cap-pieces A and C, accordingly as this current of air strikes the apparatus
from a quater above or below a horizontal plane. Should the current be
moving in a direction, at right angles to the sides of the cap-piece C, the
smoke or vitiated air will readily pass out through the top or bottom of the
space e. When the external current descends upon the top of the apparatus it
divides,, passing down the space e with a force proportionate, to the velocity of
the current, and thereby creates; a vacuum in the flue, or opening on the
principle, known as "induced currents," which. vacuum is quickly filled by
smoke or vitiated air, and a strong draft is obtained; when the said current
ascends, passing up the, space e, a similar result is obtained..
When the apparatus is applied to a railway carriage or a steam ship the
upward draft will be greatly increased-by: the speed of the same, which makes
the ventilator of great value in securing the comfort and preserving the health
of passengers, especially in emigrant ships.
Having thus fully described the construction and operation of said Inven-
tion, and illustrated several forms of applying the same, I wish it understood
that I do.not confine myself to the exact details set forth, but I claim as of

page_text: my Invention an improved ventilating cap consisting of an inner and outer
cap, the inner cap being closed at the top, and having apertures at the sides
protected by an external. cap open at the top and bottom, the sides of
two caps being inclined, and adapted to each other and to the current of
external air, so as to insure the deflection or reflection of the outer and
the free passage of the inner current from the building, chimney, or place -
to be ventilated.
In witness whereof, I have hereunto set my hand and seal, this Thirtieth
day of March, in the year of our Lord One thousand eight hundred
and sixty-five.
THOMAS BROWN. (L.S.),
Witness,
GEORGE HASELTINE,
"
International Patent Office,"
No. 8, Southampton Buildings,
Chancery Lane,
London.