Year: 1887

page_text: Date of Application, 11th Jan., 1887
Complete Left, 10th Oct., 1887
Complete Accepted, 11th Nov., 1887
1, JOHN DUNCAN GRAY THOMPSON, of the firm of Baird, Thompson and Company,
Ventilating and Sanitary Engineers, 24 Bath Street, Glasgow, Lanarkshire, do
hereby declare the nature of my Invention to be as follows:-
:-
This said Invention comprises certain improvements in the construction or com-
bination of the parts, of ventilating cowls for erecting on the top of the air or other
hollow ventilating uptake shafts, suitable for ventilating buildings, ships or other
places, and for curing smokey chimneys, and preventing blow-downs in such shafts
or chimneys.
The nature and novelty of the improvements consist as follows-In forming over
or on the top of the ordinary hollow stem of the cowl (as suitable for the tops of
house ventilating shafts) a hollow double or reverse conoidal case, with an opening
of fully the area of the shaft in the upper central part of the cone, and having the
lower cone joined close to the outer case or top stem of the cowl a few inches or so
below the top end, so that this stem would project up to this extent within the cone
and form an annular pocket to receive all rain or water which might be blown into
the cowl at top, the stem being covered with a curved baffle plate to direct the water
into this pocket which would be pierced with small holes to allow this water to
escape outside. Over this first double cone, one, two, or more open annular, or sheet
metal ring cones would be mounted at a short distance over each other, and be
surmounted by a close conical top above, all these being supported by rods or bars
The outer diameter
at their outer peripheries carried up from the lower conical case.
of these cones would preferably be about three times the diameter of the top central
stem of the cowl, and the distance between them vertically about half the diameter

page_text: of this; and the top close cone would preferably have a flat disc in it about half
way up, and about half the diameter of the stem above the cone below it, whether
that was the first, second, or third cone. When used as a cowl for chimneys, the
baffle plate over the central stem of the cowl for deflecting the water into the pocket
might be dispensed with, or kept higher than is necessary for it when used as a
ventilator on board of ship or other places where the deflector is more particularly
required.
The main novelty in the construction and combination of this ventilating cowl,
consists in the cones, and the annular conical spaces left between them, or between
these and the hollow conical top, making these to form inducing discharge cones,
which cause any lateral or downward wind or current outside the cowl from which-
ever direction it comes to so act on the flanges and in these conoidal spaces as to
cause a suction or partial vacuum in the central hollow stem of the cowl and up the
shaft, whether the outward currents pass quite through the conoidal spaces or not.
Dated this 11th day of January 1887.

page_text: COMPLETE SPECIFICATION.
Improvements in Ventilators and Chimney Cowls.
1, JOHN DUNCAN GRAY THOMPSON, of the firm of Baird, Thompson, and Company,
Ventilating and Sanitary Engineers, 24 Bath Street, Glasgow, Lanarkshire, do
hereby declare the nature of my Invention, and in what manner the same is to be
performed to be particularly described and ascertained in and by the following
statement in writing, reference being had to the accompanying Sheet of Drawings
and to the letters and figures marked thereon that is to say -
My said Invention comprises certain improvements in the construction or com-
bination of the parts, of ventilating cowls for erecting on the top of the air or other
hollow ventilating uptake shafts, suitable for ventilating buildings, ships or other
places, and for curing smoky chimneys, and preventing blow-downs in such shafts
or chimneys.
And in order that my said invention, and the manner of performing or carrying
the same into effect or practice may be properly understood, I have hereunto
appended an explanatory sheet of Drawings, in which the same reference letters are
used to indicate corresponding parts in all the figures where shown. Figure 1 is an
elevation, half in section, and Figure 2 a sectional plan, with the conoidal top
removed, taken on the line I 1 of Figure I, of a double angled duct arrangement
of my improved ventilator. While Figures 3 and 4 represent a corresponding half
sectional elevation and sectional plan on the line 3. 3 in Figure 3, of an equivalent
arrangement of ventilating cone, with an outside angled annular deflector B2 on top
for preventing blow-downs.
--
--
Referring to Figures 1 and 2 of these Drawings-the nature and novelty of my
improvements consist as follows:-In forming over or on the top of the ordinary
hollow stem S of the cowl (which is inserted into or over the shaft to be ventilated
as a spigot or faucet, as suitable for the tops of house ventilating shafts) a hollow
double or reverse conoidal case A A¹, with an opening a of fully the area of the
shaft in the upper central part of the cone, and having the lower cone A closely
joined to near the top of the hollow stem S of the cowl a few inches or so below the
top ends, so that this stem S would project up to this extent within the cone A and
form an annular pocket at a¹ to receive all rain or water which might be blown into
the cowl at top, the stem s being covered a short distance above its end with an
angled or curved baffle plate a², secured by two or more arms a¹¹to the cone A, to
direct the water into this pocket a' which is pierced with a few small holes at a¹ to
allow this water to escape outside. Over this first double cone A A', one, two,
or more open annular, or sheet metal ring cones A2, A3, would be mounted at a
short distance over each other, only one being shown in this modification, and be
surmounted by a close conical top B above, all these being supported by three or
more rods or bars Cat their outer peripheries carried up from the lower conical
case A A', and which may be made so as to assist the deflection of the currents of
air either inwards or outwards as the case may be, through the annular spaces b, b',

page_text: left between the cones A¹ A2 and the top B. The outer diameter of these cones
would preferably be about three times the diameter of the top central stem S, of the
cowl, and the distance between them vertically about half the diameter of this; and
the top close cone B, has preferably a flat disc B¹ in it about half way up, and about
half the diameter of the stem S, above the cone A² below it, whether that was the
first, second, or third cone A' A² or A³ when that is used. When used as a cowl
for chimneys the battle plate a² over the central stem S of the cowl for deflecting the
water into the pocket a might be dispensed with, as seen in Figures 3 and 4, or if
used in the cowl it might be kept higher than is necessary for it when used as a
ventilator on board of ship or other places where the deflector is more particularly
required. The action of this ventilating cowl is seen by the arrows, the air ascends
the main hollow shafts and is deflected past the baffle plate a² in the lower close
cone A A', up through the openings a in the centre of the angled cones A¹ A² to the
top B¹ where it is deflected through the upper annular conical opening 1, assisted by
the current of air outside deflected up the cone A¹ through the lower annular space b
between this and the cone A² above it.
Referring to the arrangement of ventilator shown in Figures 3 and 4, the lower
cone A¹ is shown much higher and of a more acute angle as also the angled
deflector A2 above it, as more suited for exposed and stormy places, the outer
periphery of the conical top being further shown as surmounted by an annular
deflecting sheet metal ring B2, so that when the wind blew down upon the cowl it
would pass through the annular space between the top cone B and this annular
deflector B, and by its lateral action assist the escape of the current out and down
through the annular space or duct 61 between the cone A2, and the top B, B1, B2, all
as indicated by the arrows in this Figure; this being the construction of cowl which
would be also suitable for chimney cowls.
2.
The main novelty in the construction and combination of this ventilating cowl,
consists in the cones A A1 and A2 (or A³ or A, see Diagram Figure 5 when that is
used), and the annular conical spaces b, 11, 12, 63, left between them, or 64, between
these and the hollow conical top B, B, and B2, making these to form inducing
discharge cones, which cause any lateral or downward wind or current outside the
cowl from whichever direction it comes to so act on the flanges and in these
conoidal spaces to ', as to cause a suction or partial vacuum in the central hollow
stem S of the cowl and up the shaft and the centre opening a, a, whether the outward
currents pass all round and quite through the conoidal spaces to b₁ or not.
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 construction or arrangement and combination of the parts of ventilators
and chimney cowls, all substantially as herein described and distinguished, in
reference to and shown in Figures 1 and 2, and 3 and 4, respectively of the accom-
panying Drawings.
Second. In ventilators and chimney cowls, the combination of metallic cones A, A', A²,
(or it may be A3 or A) with annular spaces to 63 between them, or between
these and the hollow conical top case B B¹ and B2, all substantially as and for the
purposes herein described in rrence to and shown in the accompanying Drawings.
Dated this 10th day of October 1887.