IMPROVEMENTS IN CHIMNEY-TOPS AND VENTILATORS
Year: 1885

page_text: I JOHN ALEXANDER MACMEIKAN of 2 Short St. Finsbury Pavement London
Sanitary & Civil Engineer do hereby declare the nature of my invention for
IMPROVEMENTS IN CHIMNEY-TOPS AND VENTILATORS" to be as follows:-
"
I construct a Chimney pot or flue of thin Terra Cotta or metal and envelope the
same in a jacket or case the outside top shoulder of which slopes towards the inner
pot or flue and leaves an opening of only about a quarter of an inch between it
and the inner pot or flue. An opening about one inch wide is left all round the
bottom of the jacket and a space is left of about one inch or more according to
diameter between the jacket and the inner pot or flue. Distance pieces or guides
are placed in the opening at the bottom of the jacket, between the jacket and the
inner pot or fiue at top and between the top of the apparatus and the bonnet which
generally surmounts it & which is open at the top. All these distance pieces or
guides slope diagonally in one direction and give a spiral direction to the air
entering the jacket and passing through into the inner pot or flue.

page_text: jacket or case slopes towards the inner pot or flue leaving an opening of about a
quarter to half an inch according to the size of the flue between such jacket or
case and the inner pot or flue, the upper portion of the inner pot or flue being
carried up by an elongation of the jacket of the same diameter, as shewn in the
annexed diagram. An opening about one inch wide is left between the bottom of
the jacket and the sloping base of the inner pot or flue as shewn by the diagram,
as a mouth to admit the external air and a similar space or slightly more is left
between the jacket and the inner pot or flue. Sloping distance pieces or guides are
placed at equal distances in the opening at the bottom of the jacket between the
jacket and the inner pot or flue, also at the top of the jacket between the jacket
and the inner pot or flue also outside the upper portion of the jacket, forming in
this latter instance a support for a bonnet or circular conical pot which surmounts
the jacket. These distance pieces all slope in the same direction and those within
the jacket may be made continuous, more or less, from top to bottom, thus giving
a twist or rotatory motion to the air passing up the jacket and entering the flue
through the opening at the top. The same series of distance pieces are placed on
the top of the bonnet or cone to support a cap or top if the same should be required
to prevent rain passing down the flue.
Referring to the diagram, which shews a section of the apparatus, A is the inner
pot or flue above described, B the jacket, elongated about two inches in this case,
C the distance pieces and D the bonnet or conical pot above described. E is the
opening at the top of the jacket, F the opening at bottom.
The operation of the apparatus is as follows: The cold external air passes into
the jacket and becoming warmed by contact with the warm surface of the inner
pot or flue and thus expanding, rises and forces its way in a spiral direction, and
with a somewhat rotatory motion, into the flue. This motion is assisted by the
wind blowing upon the opening at the bottom of the jacket and also upon the
distance pieces surmounting the same. The arrows in the diagram shew the direction
of the currents of air.
Having now particularly described and ascertained the nature of my said
Invention and in what manner the same is to be performed, I declare that what
I claim is:
The construction of an apparatus consisting in the combination of different parts
in manner bereinbefore described and for the purposes set forth.
... P
1
1000