An Improved Smoke Trap or Appliance for Preventing Down Draught in Chimneys whereby also they are Rendered Safer.
Year: 1893

page_text: Date of Application, 14th Dec., 1893
Complete Specification Left, 11th Jan., 1894-Accepted, 5th May, 1894
PROVISIONAL SPECIFICATION.
An Improved Smoke Trap or Appliance for Preventing Down
Draught in Chimneys whereby also they are Rendered Safer.
I, CHARLES WELCH, of 40 Albert Road Southsea in the County of Hampshire
Retired Grocer do hereby declare the nature of this invention to be as follows:-
The trap, to be of metal with four sides each with a clapper to be fitted so that
two sides will be by the action of the wind always closed, the opposite sides being
open at the same time to allow the smoke to escape. In some situations two clappers
would be sufficient.
Dated this 1st day of February 1894.
CHARLES WELCH,
40, Albert Road, Southsea, Hampshire.
COMPLETE SPECIFICATION.
An Improved Smoke Trap or Appliance for Preventing Down
Draught in Chimneys whereby also they are Rendered Šafer.
I, CHARLES WELCH, of 40, Albert Road, Southsea, in the County of Hampshire,
Retired Grocer, 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:-—
My invention relates to an improved smoke trap or appliance for preventing
down draught in chimneys. The appliance will work equally efficiently whether
placed upon a high or a low chimney, therefore the height may be reduced whereby
there will be less liability of any chimney being blown down and hence the structure
is rendered safer.
The
The smoke trap or appliance consists of a rectangular sheet-metal chamber of any
convenient and suitable size. It is closed at the top and in each of its sides or walls
at a suitable distance from the top, one or more openings of any suitable size are
formed, over each of which a corresponding flap or clapper" is fitted.
clappers are hinged at their lower sides, and each opposite pair is directly connected
together by a rod hinged to each. These opposite pairs of clappers are so balanced
and arranged that from whichever direction auy wind may blow the clapper or
clappers on that side of the trap will be closed and simultaneously open that or those
on the opposite side.
Referring to the accompanying drawings,
Fig. 1 is a vertical section and Fig. 2 a sectional plan on line A-B thereof, and
Fig. 3 illustrates a multiple construction.
A is the rectangular chamber which may be flanged at its base or otherwise
suitably adapted for fixture to ordinary chimney tops. It is closed at its top
preferably by a flat plate such as A' projecting for a short distance at each side.
o. o. are the opposed openings over which are fitted the clappers C C all hinged at
their lower sides a to the chamber A and adapted to open outwards for a suitable
distance, for example, 3 inches. These clappers may have side wings or not as
desired and they are connected in opposite pairs as shown by rods c pivotted at c¹
near the upper sides of the clappers, and crossing each other but not so as to touch
and cause friction.

page_text: In usual situations one pair of clappers may suffice, but otherwise I provide
several openings o. o. in each side of the chamber A as shown at Fig. 3, or in
horizontal, parallel, or otherwise, each opposed opening being fitted with coupled
clappers C C as above described.
In order to prevent the clappers chattering or causing sound below I may cause
them to bed against a strip of rubber, felt, or other flexible substance; or for the
same purpose I may fit a plate diaphragm such as B inside the chamber A, about
level with the tops of the clappers, or about where they strike the outside of the
chamber A. Thus a hollow "false head" is formed which when the clappers close
serves effectually to deaden the sound. This arrangement secures the further
advantages of increased stability to the chamber A, and also the rods c c are less
liable to injury by the brush of the chimney sweep, they being kept as near as
practicable to the underside of the said plate B.
By this construction the clapper or clappers on the windward side would always
be closed by the wind or by baffling or eddy currents of wind, and simultaneously
that or those on the leeward side would be opened, and all smoke and foul products
would escape thereat, down draught being effectually obviated. The appliance is
simple and inexpensive and may be ornamented in any required degree.
Having now particularly described and ascertained the nature of this inven-
tion and in what manner the same is to be performed, I declare that what I
claim is :-
The improved smoke trap or appliance for preventing down draught in chimneys
consisting of a rectangular chamber closed at its top and having opposite openings
in its walls each fitted with hinged flaps or "clappers" connected in opposite pairs
and arranged and operating substantially as and for the purpose above set forth.
Dated this 2nd day of April 1894.