IMPROVEMENTS IN VENTILATORS, THE SAID IMPROVEMENTS BEING APPLICABLE TO THE PREVENTION OF DOWN DRAUGHT IN CHIMNEYS AND FOR OTHER PURPOSES."
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Alexander Mill at the Office of the
Commissioners of Patents on the 20th May 1880.
ALEXANDER MILL, of Glasgow, in the County of Lanark, North Britain.
IMPROVEMENTS IN VENTILATORS, THE SAID IMPROVEMENTS BEING APPLICABLE
TO THE PREVENTION OF DOWN DRAUGHT IN CHIMNEYS AND FOR OTHER
PURPOSES."
This Invention, which has for its object improvements in ventilators, is
applicable to the drawing off or eduction of foul or vitiated air or gases from the
apartments of dwelling houses, factories, public buildings, ships' holds, cabins,
engine rooms, and other situations generally, wherein ventilators are employed,
as well as to the promotion of up draught and the prevention of down draught in
the chimneys of dwelling houses and other buildings.
The apparatus constituting the Invention consists of a tube or pipe, closed at its
upper end by a movable lid or shutter, and near its lower end provided with a
bevilled or inclined flanch or collar by which the tube or pipe rests on the upper
extremity of the ventilating shaft, or of the dwelling house, or other chimney.
From the flanch or collar to its upper end a series of ribs or projecting strips are
arranged vertically, and at regular intervals around the tube or pipe, and near
the upper end of the said tube or pipe, in the space between each of the said ribs
or projecting strips, an opening or slot is cut in the tube. Each of the vertical
ribs or strips is formed with a shoulder or flanch near its lower end, and on the
said shoulders an outer tube rests. The outer tube extends upwards to the level
or above the level of the upper end of the tube or pipe first referred to, so that
betweeen the two tubes an annular space is formed, the said space being divided
into sections or compartments by the vertical ribs or strips. Between the lower
end of the outer tube and the inclined or bevilled flanch or collar of the inner
tube there is also a space open to the atmosphere and divided into sections by the
ribs or strips. The effect of this arrangement is that a current of atmospheric air
in passing into the annular spaces between the tubes from the spaces between the
lower end of the outer and the flanch or collar on the inner tube is directed
upwards, and in escaping at the upper end of the ventilator produces an upward
or inducing current through the interior tube, whereby the foul or vitiated air,
gases, or smoke is drawn outwards through the slots or openings near the upper
Prins 11

page_text: end of the said tube. Similarly when the current of atmospheric air blows
downwards from the top of the ventilator a like upward inducing action is
produced in the inner tube by the said current in escaping through the spaces at
the lower end of the outer tube.
Under a modification of the apparatus the outer tube extends downwards to the
flanch or collar of the inner tube, in which case the said flanch or collar is
perforated to allow currents of atmosperic air to pass upwards through it, and
the inner tube may or may not have a. bevil or taper towards its upper end, and
be provided with a second series of openings for the outward passage of the foul
or vitiated air, gases, or smoke.