Improvements in Tops or Cowls for Chimneys, Ventilating Shafts, or the like.
Year: 1893

page_text: Date of Application, 14th Feb., 1893
Complete Specification Left, 11th Nov., 1893-Accepted, 30th Dec., 1893
PROVISIONAL SPECIFICATION.
Improvements in Tops or Cowls for Chimneys, Ventilating Shafts,
or the like.
I, WILLIAM DAVIS of 3 Oval Chambers, Kennington Oval, London, S.E.,
Whitesmith, do hereby declare the nature of this invention to be as follows:-
This invention relates to cowls or ventilating shaft tops or similar apparatus for
chimneys ventilating shafts or the like purposes and is designed more especially to
produce an absolutely automatic down-draught preventer which at the same time
permits perfect freedom of egress from the outlet of the chimney etc.
My present invention is as follows:-
My top or cowl is formed to fit directly over or onto the top of the chimney or
shaft etc. to which it is to be applied or may be fitted on to an intermediate length
of pipe chimney pot or "tallboy" as desired and for the sake of example I will
describe my improvements as applied to the latter.
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The upper outlet of the tallboy' enters within a hood cap or chamber of
cylindrical (or other suitable) form or shape of a much larger size in cross section
so that a considerable annular or other space remains between the tallboy and such
surrounding hood or chamber to which latter there is no bottom or impediment to
free egress when required.
Within this chamber or hood and near the top thereof I arrange and mount two
or other suitable number of flaps or lids to entirely cover and control the opening
or passage through the said hood or chamber after the manner of outlet flap valves.
For facility of description I will describe the arrangement and use of two such
flap valves:
Inside the aforesaid hood I mount in any suitable manner (for instance by
soldering or rivetting) a ring or ledge to act as the valve seating for said flaps.
The two flaps are hinged back to back on a bar fixed across the diameter of the
said hood or otherwise suitably mounted so that the free ends of the flaps can rise
off their said seatings.
These said flaps are advantageously made of mica or other light material of a heat
and exposure resisting nature or instead thereof I may make these flaps of other
suitable material such as metal and provide same with a counterbalance or counter-
balances so that the flaps will readily rise and open to permit egress from the
chimney etc.
A cross bar or other suitable device above the flaps prevent same opening too
far for my purpose and I may advantageously provide a stay bar or bars or other
strengthening device to resist strain or concussion on the said hinge bar in case
same should be struck by the sweepers brush or other device.
In operation-the flaps will readily rise to permit or induce free egress from the
chimney or shaft etc. but directly there is any tendency to down draught the flaps
will promptly close on their seatings and effectually prevent any entrance of wind
down the chimney etc. while the products coming up the chimney etc. will continue
and pass away through the aforesaid open passage at the bottom of the hood.
Dated this 14th day of February 1893.
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.

page_text: COMPLETE SPECIFICATION.
Improvements in Tops or Cowls for Chimneys, Ventilating Shafts,
or the like.
I, WILLIAM DAVIS of 3, Oval Chambers, Kennington Oval, London, S.E.
Whitesmith, 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 :-
This invention relates to cowls or ventilating shaft tops or similar apparatus for
chimneys ventilating shafts or the like purposes and is designed more especially to
produce an absolutely automatic down-draught preventer which at the same time
permits perfect freedom of egress from the outlet of the chimney etc.
My present invention is as follows:-
دو
My top or cowl is formed to fit directly over or onto the top of the chimney or
shaft etc. to which it is to be applied or may be fitted on to an intermediate length
of pipe chimney pot or "tallboy as desired and for the sake of example I will
describe (with reference to the accompanying drawings) my present improvements
as applied to the latter.
Fig. 1 in the drawings annexed represents my cowl in ordinary action.
Fig. 2 represents the action when there is any tendency to a "down-draught."
The upper outlet of the "tallboy "A enters within a hood cap or chamber B of
cylindrical (or other suitable) shape or form of a much larger size than A in cross
section so that a considerable annular or other space remains between the tallboy A
and such surrounding hood or chamber B to which latter there is no bottom or
impediment to free egress when required.
Within this chamber or hood B and near the top thereof I arrange and mount
two or other suitable number of flaps or lids C C to entirely cover and control the
opening or passage through the said hood or chamber B after the manner of outlet
flap valves.
For facility of description I will describe the arrangement and use of two such
flap valves as shown in the drawings.
Inside the aforesaid hood I mount in any suitable manner (for instance by
soldering or rivetting) a ring or ledge D to act as the valve seating for said flaps C.
The two flaps C are hinged back to back on a bar E fixed across the diameter of
the said hood or otherwise suitably mounted so that the free ends of the flaps C can
rise off their said seating D.
These said flaps are advantageously made of mica or other light material of a
heat-resisting and exposure-resisting nature; or instead thereof I may make these
flaps C of other suitable material such as metal and provide same with a counter-
balance or counterbalances (not shown) so that the flaps C will readily rise and
open to permit egress from the chimney etc.
A cross bar or other suitable device may be used above the flaps to prevent
same opening too far for my purpose and I may advantageously provide a stay bar
or bars or other strengthening device below the hinge bar E to resist strain or
concussion on the said hinge bar E i.e. to prevent same from being struck by the
sweepers brush or other device.
In operation-the flaps C will readily rise to permit or induce free egress from
the chimney or shaft etc. as shown in Fig. 1-but directly there is any tendency to
down draught the flaps will promptly close on their seatings as shown in Fig. 2 and
effectually prevent any entrance of wind down the chimney etc. while the products
of combustion coming up the chimney etc. will continue and pass away through the
aforesaid open passage at the bottom of the hood as in Fig. 2.
If desired the seatings of the valves or flaps C may be on an incline instead of
horizontal as shown.

page_text: Having now particularly described and ascertained the nature of my said inven-
tion and in what manner the same is to be performed I declare that what I
claim is :-
1. In combination with a chimney top tallboy or other chimney outlet such as A
-a cowl or hood such as B of greater diameter than A a binge bar internally
arranged and mounted across said cowl a flap or flaps such as C hinged to said bar
and of such a size that when closed on their seatings same will completely close the
passage through B and thereby prevent down-draught substantially in the manner
and for the purposes herein before described and illustrated by way of example in
the drawings hereunto annexed.
2. A cowl or hood such as B adapted to fit loosely over the chimney outlet such
as A so that a clear passage is left between the outer wall of A and the inner wall
of B in combination and acting in conjunction with a flap or flaps such as C adapted
to completely and automatically close the passage through B when there is any
tendency to down-draught substantially in the manner and for the purposes herein-
before described.
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1009
TONGUE & BIRKBECK,
34, Southampton Buildings, Chancery Lane, London, W.C.,
Agents for the Applicant.