An Improved Self Acting Ventilator.
Year: 1891

page_text: Date of Application, 23rd Apr., 1891-Accepted, 23rd May, 1891
COMPLETE SPECIFICATION.
An Improved Self Acting Ventilator.
A communication from abroad by WILLIAM ADOLPHUS SMYRK, of No. 200, Cecil
Street, Albert Park, near Melbourne, in the Colony of Victoria, Joiner, and
MONTAGUE BARNETT, and BAREND BARNETT, both of No. 407, Collins
Street, Melbourne, aforesaid, Importers.
I, GEORGE CLEMENT DOWNING of 8 Quality Court London W.C. England
Patent Agent do hereby declare the nature of my said 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 has been devised for the purpose of providing a ventilator which
will admit of an outflow of air from the room or compartment in which it is placed,
but which will prevent such an inflow of air from the outside as would cause a
draught.
It consists of a metal, wooden or other box or case of the ordinary shape and size
in the sides of which a flap is so pivoted as that the upper part just over-
balances the lower part. This I prefer to accomplish by pivoting it just below
its centre. The section of this flap is made in a shape approximating that of
the letter S, and stops (preferably of india-rubber) are provided in the side for
the purpose of preventing the tail of this flap from rising too high. The lower
half of that part of the box or case which faces the outside of the room is
provided with a curved or concave face leading into the concave part of the upper
part of the flap.
By pivoting the flap a little below its centre it is evident that its upper part
will have a normal tendency to fall outwards so as to allow of an outflow of air, and
the circular or concave form of its upper half and also of the lower half of the
outer face of the box or case tends to close said flap on a comparatively slight
inward flow, and thus it acts automatically in preventing draughts and yet admits
of a sufficient outflow from the room or chamber.
Referring to the accompanying drawings,
Figure 1 is a front elevation of the inside of a ventilator constructed according
to this invention, and showing same open.
Figure 2 is a similar view of the outside thereof, also showing same open, whilst
Figure 3 is a vertical transverse section on line 3-3, Figure 1, and
Figure 4 is a similar view to Figure 3, but showing said ventilator closed.
Similar letters of reference indicate the same parts in all the figures.
A represents the flap which, as hereinbefore mentioned, is made approximately
S-shaped in cross-section, and is pivoted or supported upon trunnions B working in
bearings in the side-plates C of the ventilator casing. The upper part of this
pivoted flap A slightly overbalances its lower part, and this, under normal condition
keeps such lower part pressing against the rubber-covered or other noiseless
stops D-D which project inwards from the sides C of the ventilator casing.
E represents the concave face on the outside of the ventilator over which the upper
part of the flap A projects, as illustrated in Figure 3, so as to form a recess, which
will, as it were, catch any wind blowing against the ventilator from the outside, the
effect of even a light puff being sufficient to raise the upper part of the flap A until
it contacts with the roof of the casing, as illustrated in Figure 4, when, as will be
obvious, it will effectually prevent any air passing through the ventilator from the
outside. When not closed in this way the air inside the building will be free to
pass out, it being obvious that it will produce no effect either one way or the other
upon the pivoted flap A.

page_text: 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 :-
First. The herein described ventilator consisting essentially of an approximately
S-shaped flap so pivoted in its case as that its upper part just over-balances its
lower part and preferably by pivoting it a little below its centre, substantially as
and for the purposes herein described and explained and as illustrated in the
accompanying drawings.
Second. In a ventilator the combination with an approximately S-shaped flap so
pivoted in its case as that its upper part just over-balances its lower part of a
curved or concave face or plate (such as E) leading into the concave upper part of
the flap, and preferably with stop pieces (such as D), the whole being constructed
arranged and operating substantially as and for the purposes herein described and
explained and as illustrated in the accompanying drawings.
Dated this 23rd day of April One thousand eight hundred and ninety-one.
GEORGE C. DOWNING.