IMPROVEMENTS IN CHIMNEY TOPS AND IN APPARATUS APPLIED THERETO FOR PREVENTING DOWN-DRAFT AND THEREBY CURING SMOKY CHIMNEYS AND VENTILATING INTERIORS OF BUILDINGS AND OTHER STRUCTURES " PRO SP
Year: 1882

page_text: LETTERS PATENT to John McPhail of the Minories in the City of London for
an Invention of "IMPROVEMENTS IN CHIMNEY TOPS AND IN APPARATUS
APPLIED THERETO FOR PREVENTING DOWN-DRAFT AND THEREBY CURING
SMOKY CHIMNEYS AND VENTILATING INTERIORS OF BUILDINGS AND OTHER
STRUCTURES
"
PROVISIONAL SPECIFICATION left by the said John McPhail at the Office.
of the Commissioners of Patents on the 19th September 1882.
JOHN MCPHAIL of the Minories in the City of London, "IMPROVEMENTS IN
CHIMNEY TOPS AND IN APPARATUS APPLIED THERETO FOR PREVENTING DOWN DRAFT
AND THEREBY CURING SMOKY CHIMNEYS AND VENTILATING INTERIORS OF BUILDINGS'
AND OTHER STRUCTURES
">
For this purpose in carrying out my invention I construct a chimney top with
double outlets which curve or branch off at opposite angles from the main outlet
passage near to the top of the chimney flue or shaft. Or a chimney pot may be
formed in like manner with double outlets.
Each outlet is advantageously cut off at an angle of
cover being supported a short distance above each outlet.
together and carried by an axis or upon bearings upon
balanced like a pair of scales.
45 degrees more or less a
The covers are connected
which the two covers are
Wing pieces or vanes are attached to or depend from the axes of the covers so
that the slightest current of air acting thereon causes one of the covers to act as a
valve and close down over that outlet of the chimney which is opposite to the
direction of the wind thus preventing any down draft the wind or current of air
at the same time acting to exhaust the air and withdraw the smoke from the,
opposite outlet of the chimney.
The apparatus also acts as a ventilator to the interior of a building or other
structure to which it may be applied
The form and arrangement of the parts may be varied without departing from
the nature of my invention.

page_text: In order to minimise noise from the movement of the valves or covers coming in
contact with the chimney wire or springs or other fire proof material may be used
as buffers.
The longitudinal position of the outlets should be at right angles to the two
directions in which the wind is least prevalent and for this country would be most
suitable at W.N.W. and E.S.E. when practicable as such position would be attended
with less movement from the prevalent winds.
The chimney or ventilator branches off towards the top in opposite directions
with two outlets each outlet having the plane of its orifice sloping downwards at
an angle of forty five degrees more or less. The branching of the chimney or
ventilator is in order to give each outlet the area of the main shaft which
branching only requires to exceed the diameter of the shaft by a fourth.or
thereabouts
Near the top of the chimney or bent and between the outlets there is an axis
nearly parallel to the plane of the outlets on which axis is balanced a cover or
covers for both outlets each sloping downwards at an angle of twenty two and a
half degrees more or less from the centre above the axis causing when there is no
current of air or when the wind is parallel with the axis an opening of twenty
two and a half degrees more or less on each outlet also with or without a vane or
vanes attached perpendicular to and parallel with the axis.
The principle involved is that by the angular form of the cover or covers the
upper surface of the cover on the windward side (and the lower side of the
leeward cover in general as well as the windward side of the vane or vanes when
used) presents a greater area of surface to the wind or current of air the result
causes the covers to move on the axis towards the wind and the windward cover
increases in effectiveness until it rests on the plane of the windward outlet leaving
the leeward outlet open to the full discharge of the main shaft with the said
leeward cover in or near a horizontal position
From the construction and action of the parts it is immaterial from what direction
the wind strikes as the covers will act instantaneously no matter how quick the
wind varies and even if the current of air is direct downwards there will be an
up draft or current in the shaft
This improved construction of chimney top also tends to cause a draught from.
the wind increasing proportionately with the increase of wind.
The cover or covers prevent rain from going down the chimneys or ventilators.
The motion from opening one until closing the reverse outlet is only the eighth
part of a revolution and from the stationary position until the closing of either
outlet is only the sixteenth of a revolution thereby minimising friction.
The apparatus is also applicable so as to cause a down draught in any interior by
reversing the position of the angles of the covers and balancing by weight thus
reversing the effect by which a down-draught is obtained.
This improved ventilating apparatus also dispenses with the extra height of
chimney cans or tops and is as effective a foot high as at one hundred and will
save carrying long shafts from low buildings that are attached to or affected by
high buildings in their vicinity.
It is also applicable for steamers funnels and for ships galleys steam or sail as
often in the latter there is a downdraft from the sails.
Also for ventilating holds and preventing rain getting at the cargo as is often
the case through the ventilators in common use.
The apparatus can be made to any size and of a variety of forms.
The moving parts of the apparatus require to be made of metal.
The chimney or ventilator top can be made of brick or the ordinary materials
now commonly in use or of metal or any other suitable material.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent filed
by the said John McPhail in the Great Seal Patent Office on the 19th March
1883.
JOHN M. PHAIL of the Minories in the City of London
"IMPROVEMENTS IN
CHIMNEY TOPS AND IN APPARATUS APPLIED THERETO FOR PREVENTING DOWN DRAFT
AND THEREBY CURING SMOKY CHIMNEYS AND VENTILATING INTERIORS OF BUILDINGS
AND OTHER STRUCTURES
"
For this purpose in carrying out my invention I construct a chimney top a with
double outlets a¹ a² which curve or branch off at opposite angles from the main
outlet passage a near to the top of the chimney flue or shaft as represented in
Figures 1, 2, 3 and 4 of the drawings hereto annexed. Or a chimney pot may be
formed in like manner with double outlets.
Each outlet a¹ a² is advantageously cut off at an angle of 45 degrees more or less
a cover b being supported a short distance above each outlet. The covers bare
connected together and carried by an axis 6' or upon bearings upon which the two
covers b b are balanced like a pair of scales.
Wing pieces or vanes 62 indicated by dotted lines in Figure 2 may be attached to
or depend from the axes of the covers 6 b so that the slightest current of air acting
thereon causes one of the covers b to act as a valve and close down over that outlet
of the chimney which is opposite to the direction of the wind thus preventing any
down draft the wind or current of air at the same time acting to exhaust the air
and withdraw the smoke from the opposite outlet of the chimney.
The apparatus also acts as a ventilator to the interior of a building or other
structure to which it may be applied.
The form and arrangement of the parts may be varied without departing from
the nature of my invention.
In order to minimise noise from the movement of the valves or covers coming in
contact with the chimney wire or springs or other fire proof material may be used
as buffers.
The longitudinal position of the outlets should be at right angles to the two
directions in which the wind is least prevalent and for this country would be most
suitable at W,N.W, and E,S,E, when practicable as such position would be
attended with less movement from the prevalent winds.
The chimney or ventilator a branches off towards the top in opposite directions
as shown by Figures 1 and 2 with two outlets a¹ a² each outlet having the plane of
its orifice sloping downwards at an angle of forty five degrees more or less.
The branching of the chimney or ventilator is in order to give each outlet the
area of the main shaft which branching only requires to exceed the diameter of the
shaft by a fourth or thereabouts.
Near the top of the chimney or bend and between the outlets there is an axis b¹
nearly parallel to the plane of the outlets on which axis is balanced a cover or
covers 6b for both outlets each sloping downwards at an angle of twenty two and
a half degrees more or less from the centre above the axis 6' causing when there is
no current of air or when the wind is parallel with the axis an opening of twenty
two and a half degrees more or less on each outlet also with or without a vane or
vanes 6 attached perpendicular to and parallel with the axis.
The principle involved is that by the angular form of the cover or covers bb the
upper surface of the cover b on the windward side (and the lower side of the leeward
cover in general as well as the windward side of the vane or vanes 6' when used)
presents a greater area of surface to the wind or current of air the result causes the

page_text: covers to move on the axis b¹ the windward cover increases in effectiveness until it
rests on the plane of the windward outlet leaving the leeward outlet open to the
full discharge of the main shaft with the said leeward cover in or near a horizontal
position.
From the construction and action of the parts it is immaterial from what
direction the wind strikes as the covers b b will act instantaneously no matter how
quick the wind varies and even if the current of air is direct downwards there will
be an up draft or current in the shaft.
This improved construction of chimney top also tends to cause a draught from
the wind increasing proportionately with the increase of wind.
The cover
ventilators.
or covers 66 prevent rain from going down the chimneys or
The motion from opening one until closing the reverse outlet is only the eighth
part of a revolution and from the stationary position until the closing of either
outlet is only the sixteenth of a revolution thereby minimising friction.
This improved apparatus also dispenses with the extra height of chimney cans or
tops and is as effective a foot high as at one hundred and will save carrying long
shafts from low buildings that are attached to or affected by high buildings in their
vicinity.
It is also applicable for steamers funnels and for ships galleys steam or sail as
often in the latter there is a down draught from the sails.
Also for ventilating holds and preventing rain getting at the cargo as is often the
case through the ventilators in common use.
The apparatus can be made to any size and of a variety of forms. The moving
parts of each apparatus previously described requires to be made of metal. The
chimney or ventilator top can be made of brick or the ordinary materials now
commonly in use or of metal or any other suitable material.
This improved apparatus is also applicable so as to cause a down-draught in any
interior by reversing the position of the angles of the covers b b and balancing by.
weight thus reversing the effect by which a down draught is obtained. An air
shaft top a having balanced covers b b constructed and applied in accordance with
this part of my improvements is represented by Figures 5 and 6 of the drawings
annexed.
These combined covers bb are balanced on an axis b¹ across the centre and above
the flange of the ventilator. The balanced cover is divided off at the centre into
two leaves or valves bb and when still or in a calm balance with each wing or
valve at an angle of 23 degrees more or less off the horizontal.
The covers or valves b b are concave towards the entrance to conduct the wind
into the air shaft a and convex on the opposite sides and as the wind strikes the
concave side on the windward and the convex side to leeward it thereby causes.
the windward valve to open to an angle of 45 degrees more or less and closes
the leeward valve causing a constant down draught in the air shaft a.
It is effective three fourths of the compass or 24 out of 32 points of the compass
and requires no attention. Any noise that may arise can be minimised by using
india rubber rings asbestos or other suitable substance.
Figures 7 and 8 show a conical circular shield 6 moving to an angle of
221/2 degrees or thereabout at all points of the compass being balanced on a pivot c
bearing on a socket c¹ with a circular ring bearing c² above and between which is a
locking washer c³ on the pivot bolt c preventing it being blown off or going past
the prescribed angle all of which parts are supported on a tripod d or other suitable
support fixed to the sides of the chimney top a.
The said shield b instantaneously oscillates and closes towards the direction of
the wind thereby preventing downdraught and allowing freedom to the updraught.
When there is no wind there is an open space all round between the edge of the
shield and the chimney top equal to the area of the shaft or chimney a.
The friction is of the minimum and the noise is almost imperceptable and it
requires no attention or lubrication of any description.

page_text: Figures 9 and 10 shew an upcast ventilator or cowl b acting by means of a
circular shield b representing that section of a sphere from latitude 38 degrees or
thereabout to the pole and which works on a ball in a socket c¹ supported by a
tripod d or other suitable support and bearing with its edge on the rim a* of
the flanged chimney or ventilator a and the shield 6 will oscillate always presenting
the convex side to the action of the wind thereby allowing free exit to the foul air.
or smoke and preventing rain from going down the shaft or chimney a
Having thus described the nature of my invention and the manner of performing
or carrying the same into practice I would remark that I make no claim to any
of the parts separately which are well known and in common use neither do
I limit myself to the exact details herein before described so long as the essential
character of my invention is retained But what I claim is :—
First. The improved arrangement and construction of chimney tops having
apparatus applied thereto for preventing down draught such as is shown and
described with reference to Figures 1, 2, 3, 4, 7, 8, 9, and 10 of the drawings
hereto annexed.
Second. I claim the improved arrangement and construction of down cast air
shaft tops having apparatus applied thereto for ventilating interiors of buildings
ships holds and other structures such apparatus being arranged to act substantially
in the manner and for the purposes hereinbefore described and represented in
Figures 5 and 6 of the drawings hereto annexed.
Third. I claim the improved general arrangement and construction of chimney
tops combined with apparatus for preventing down draught and for ventilating the
interiors of buildings arranged to act substantially in the manner and for the
purposes hereinbefore described and represented in the drawings hereto annexed.
In witness whereof I the said John Me. Phail have hereunto set my hand and
seal this Seventeenth day of March in the year of our Lord One thousand
eight hundred and eighty three.
JOHN MOPHAIL (L.S.)