An Improvement applicable to Chimney Tops.
Year: 1894

page_text: An Improvement applicable to Chimney Tops.
I DAVID CURR of 10 Cromwell Street Edge Lane, Stretford in the County of
Lancaster Commercial Traveller do hereby declare the nature of this invention to
be as follows:-
This invention relates to an improvement applicable to chimney tops to prevent
downdraught & to cure what are known as "smoky chimneys."
The invention consists principally of a kind of casing surrounding the ordinary
chimney pot the casing is formed of one or more circular & cone shaped tubes, the
lowest cone embraces the chimney pot by fitting over, & on to the chimney pot
like an inverted extinguisher, the lowest cone is somewhat greater in diameter than
the chimney pot, the second cone fits into the lowest cone & over the chimney pot
and the third in a similar manner.
The cones are fixed to the chimney pot by bands on the lowest cone, and by
bands on the second to the lowest cone, and by bands on the second to the third
cone, so as to allow a space between each cone through which smoke can escape.
The top cone is surmounted by a circular cap elevated somewhat above the top
cone & allowing a space all round for escape of smoke. A girdle surrounds
this latter space to prevent any direct draught of wind blowing into the casing-
the tube or chimney pot encased is placed so that no direct or deflected draught
can impinge upon the exit or mouth of the chimney pot. The cones increase in
diameter from bottom to top cone.
*1.2004
An Improvement applicable to Chimney Tops.
1 DAVID CURR of 10 Cromwell Street Edge Lane Stretford in the County of
Lancaster Commercial Traveller 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 an improvement applicable to chimney tops to prevent
downdraught and to cure what are known as smoky chimneys. The invention
consists principally of a kind of casing surrounding the ordinary chimney pot by
fitting over and on to the chimney pot. The casing is formed of one or more
circular & cone shaped tubes, the lowest cone embraces the chimney pot by fitting
over & on to the chimney pot like an inverted extinguisher & rests on nogs
which jut out from the chimney pot. The lowest cone is greater in diameter than
the chimney pot. The second cone fits into the lowest cone and over the
The cones are fixed to each
chimney pot and the third cone in a similar mauner.
other by bands which keep the cones apart in order to allow smoke to escape.
The top cone is surmounted by a circular cap elevated above the top cone & fixed
to it by bands which keep them apart and permit smoke to rise out through

page_text: the space between the top cone and the cap. This space is surrounded by a
girdle BB sufficiently deep to protect the interior of the casing from any direct or
deflected current of wind. The cones increase in diameter from bottom to top.
The casing may be composed of clay or metals.
This invention makes it impossible for any down striking current of wind to
impinge upon the chimney pot at A A, and in every case of down striking wind an
accelerated draught is produced in the chimney upwards in response to the
induction produced by the velocity of the wind flowing through the cone spaces
downwards. The most important feature of this invention is the avoidance of
back pressure in the chimney pot arising from the frequently deflected_uprushes
of wind currents. An uprush would strike the ceiling of the cap and cause a
severe down draught unless the casing were so constructed that the inlets C C
provide less space than the alternative exits above them. The position of the
walls of the cones procure an induction either in down blow or up draught. The
raising of the walls of the top cap considerably above the girdle B B protects the
leward opening at BB from wind pressure or deflection and so provides an
uninterrupted exit & partial vacuum for the smoke issuing from A A.
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 :-
1st. The use on chimney pots of cones or lifts which increase in diameter from
bottom to top in order to freely admit a down striking wind & baffle an uprush.
2ndly. The carrying up of the shaft or pot as in AA to the centre of the third
top cone or lift.
3rdly. The raising of the walls of the surmounting cap considerably above the
girdle B B.