IMPROVEMENTS IN THE MANUFACTURE OF VENTILATORS: AND CHIMNEY POTS
Year: 1869

page_text: LETTERS PATENT to George Hawksley, of Montrose Villas,
Caledonian Road, in the County of Middlesex, Engineer, for the
Invention of "IMPROVEMENTS IN THE MANUFACTURE OF VENTILATORS: AND
CHIMNEY POTS."
Sealed the 27th July 1869, and dated the 29th January 1869.
PROVISIONAL SPECIFICATION left by the said George Hawksley at
the Office of the Commissioners of Patents, with his Petition, on the
29th January 1869.
I, GEORGE HAWKSLEY, of Montrose Villas, Caledonian Road, in the
County of Middlesex, Engineer, do hereby declare the nature of the
said Invention for "IMPROVEMENTS IN THE MANUFACTURE OF VENTILATORS AND
CHIMNEY POTS," to be as follows:-
This Invention has for its object improvements in the manufacture of
ventilators and chimney pots, and relates especially to ventilators and
chimney pots which have lateral openings so formed that currents of
wind entering by such openings may cause an upward draft within the
ventilator or pot. Such ventilators or pots I produce from a long
metal band, say of hoop iron, which I form into a coil by extending it

page_text: on one edge more than on the other. I do this by passing the hoop
iron between rollers which are set so as to form a taper nip, and the
rollers may be so formed as simultaneously to give to the iron a
'curved face. Or in place of expanding the outer edge of the hoop iron
a similar result may be obtained by corrugating its inner edge. I then
take a cylindrical mandril of the size of the interior of the ventilator or
pot which it is desired to produce and having in it a number of
longitudinal radial grooves equidistant the one from the other. In
these grooves other flat pieces of hoop iron are placed having inclined
notches in them at equal distances apart from end to end of each
piece. On the mandril so prepared I wind the curved hoop iron before
mentioned so as to form a helical coil and fitting it into the inclined
notches in the pieces in the grooves in the mandril; at one end
of these pieces I fix a suitable top or cover. I rivet the upper and
lower coils of the hoop iron or otherwise suitably secure the ends, I
remove the mandril and galvanize the combined parts, and so at once I
protect them from the weather and firmly fix every joint.
I also make similar ventilators and pots of cast-iron. I cast a series
of similar rings which when placed one above the other leave the lateral
openings required for the entrance of the wind; I accumulate such
rings to the height desired, then place a cap on the upper ring, and
by a bolt from end to end of the series I bind the whole together.
In constructing ventilators I sometimes employ two coils or sets of
rings one over the other and in connection with separate air passages,
so that one coil or set of rings may produce an up current in one
channel, whilst the other coil or set of rings produces a down current
in the other channel; the coils or rings should then be placed so as to
incline in opposite directions.
In constructing ventilators or chimney pots with cowls or hoods the
mouths of which turn from the wind, I form on the weather side or face
of the cowl horizontal slits or openings each with a lip on the lower
edge projecting into the interior and inclined upwards, so that the wind
entering these slits is directed up so as to sweep round the top of the
cowl, producing an upward suction in the flue without impeding the
draft.

page_text: SPECIFICATION in pursuance of the conditions of the Letters Patent,
filed by the said George Hawksley in the Great Seal Patent Office
on the 29th July 1869..
TO. ALL TO WHOM THESE PRESENTS SHALL COME, I, GEORGE
HAWKSLEY, of Montrose Villas, Caledonian. Road, in the County of.
Middlesex, Engineer, send greeting..
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-ninth day of January, in the.
year of our Lord One thousand eight hundred and sixty-nine, in the
thirty-second year of Her reign, did, for Herself, Her heirs and succes-
sors, give and grant unto me, the said George Hawksley, Her special*
licence that I, the said George Hawksley, my executors, adminis-.
trators, and assigns, or such others. as. I, the said George Hawksley;..
my executors, administrators, and assigns;, should; at any time agree
with, and no others, from time to time and at all times. thereafter
during the term therein expressed, should and lawfully might make,
use, exercise, and vend, within the United Kingdom of Great Britain
and Ireland, the Channel Islands, and Isle of Man, an Invention for
"IMPROVEMENTS IN THE MANUFACTURE OF VENTILATORS AND CHIMNEY POTS,"
upon the condition (amongst others) that I, the said George Hawksley,.
my executors or administrators, by an instrument in writing, under my,.
or their, or one of their hands and seals, should particularly describe
and ascertain the nature of the said Invention, and in what manner
the same was to be performed, and cause the same to be filed in the
Great Seal Patent Office within six calendar months next and immediately.
after the date of the said Letters Patent..
NOW KNOW YE, that I, the said George Hawksley, do hereby
declare the nature of the said Invention, and in what manner the same
is to be performed, to be particularly described and ascertained in and
by the following statement thereof, that is to say :-
This Invention has for its object improvements in the manufacture of
ventilators and chimney pots, and relates especially to ventilators and
chimney pots which have lateral openings so formed that currents of
wind entering by such openings may cause an upward draft within the
ventilator or pot. Such ventilators or pots I produce from a long metal
band, say of hoop iron, which I form into a coil by extending it on one
edge more than on the other. I do this by passing the hoop iron between

page_text: rollers which are set so as to form a taper nip, and the rollers may be so
formed as simultaneously to give to the iron a curved face. Or in place
of expanding the outer edge of the hoop iron a similar result may be
obtained by corrugating its inner edge. I then take a cylindrical
mandrel of the size of the interior of the ventilator or pot which it is
desired to produce and having in it a number of longitudinal radial
grooves equidistant the one from the other. In these grooves other flat
pieces of hoop iron are placed having inclined notches in them at equal
distances apart from end to end of each piece. On the mandril so pre-
pared I wind the curved hoop iron before mentioned so as to form a
helical coil, and fit it into the inclined notches in the pieces in the
grooves in the mandril; at one end of these pieces I fix a suitable top or
cover. I rivet the upper and lower coils of the hoop iron or otherwise
suitably secure the ends, remove the mandril, and galvanize the combined
parts, and so at once I protect them fron the weather and firmly fix
every joint.
Figure 1 shews a side view of a-chimney pot or ventilator constructed
as above described, a is the metal band forming the helical coil. This
band to bring it into a coiled form is passed between rollers set at an
angle to one another to form a taper nip, and the rolls I also form by
preference curved on their circumference to bring the band to a section,
such as is shewn in the diagram view Figure 2. I form the passage
between the rolls of the width of the strip or band of metal, and provide
one of the rolls with side flanges to come at the sides of the other roll,
and so ensure that the strip shall pass correctly between the rolls, or the
strip might be otherwise guided truly in its passage through the rolls.
I prefer that the band as it comes from the rolls should form a coil of
about double the diameter of the pot or ventilator to be formed, in order
that when the band is coiled to a helical coil of this smaller diameter
the several coils of the band may incline downwards, as shewn by the
Drawing. By forming the strip to a curved section, as shewn by the.
diagram Figure 2, an upward direction will be given to the air as it
passes into the coil, and the speed of the current of air passing into the
coil will also be accelerated, as the passages between the plates will be
thereby contracted from the exterior to the interior.
Figure 3 shews an edge view of one of the strips of metal 6 to which
the helical coil is to be connected; 6' are the inclined notches in this
strin to receive the edge of the several coils of the hand a

page_text: Figure 4 shews a side view, and Figure 5 a plan view of the mandril
employed for holding the strips 6 whilst the band a is being coiled around
them. Radial grooves care, as above described, formed in this mandril,
and into these grooves the strips 6 are inserted and are held there whilst
the band a is being wound around them. When commencing to coil the
band around the strips 6 the end of the band is passed once around the
mandril and the strips held therein and is then rivetted up to form a
hoop. When the coiling of the band is completed the opposite end of
the band is similarly rivetted up into a hoop, and so the end is secured;
the coil and strips are then taken off the mandril and are connected by
rivetting to top and bottom pieces, as shewn at Figure 1. The whole is
then galvanized, as above described, and the ventilator or pot is completed.
As before stated in place of one edge of the band a being extended, as
above described, one edge of the band might be corrugated, and the same
result would be obtained.
In the pots or ventilators shewn at Figures 1 and 2 the several rings
of the helical coil incline downwards, but if when used as a ventilator
it is desired to force air downwards into a room or building the coils
would be made to incline in the opposite direction.
I also make similar ventilators and pots to those above described of
cast iron, I cast a series of similar rings which when placed one above
the other leave the lateral openings required for the entrance of the
wind. I accumulate such rings to the height desired, then place a cap
on the upper ring, and by a bolt from end to end of the series I bind the
whole together.
Figure 6 shews a ventilator or chimney pot so constructed. The rings
a, a, are cast with curved inclined sides, as shewn by the Drawing, and
are also cast with internal lugs upon them, as shewn by the sectional
view Figure 7, taken through the side of one of the rings; the lugs on
the bottom of one ring rest on the top edge of the ring below it. The
top of the ventilator or chimney pot is similarly built up of rings b, b,
of cast iron, and the base of the pot is formed of a cylinder c, across the
top of which a bar c³ passes. A tie rod is passed down through the
top cover of the pot and through the bar c³, and the whole is screwed up
firmly together.
In constructing ventilators I sometimes employ two coils or sets of
rings one over the other and in connection with separate air passages, So
that one coil or set of rings may produce an up current in one channel,

page_text: .whilst the other coil or set of rings. produces a down current in the other
channel; the coils or rings. should then be placed so as to incline in
opposite directions.
In constructing ventilators or chimney pots with cowls or hood's the
mouths of which turn from the wind, I form on the weather side or face
of the cowl openings or passages between plates inclining upwards. so.
that the wind entering these openings is directed up so as to. sweep.
round the top of the cowl, producing an upward suction in the flue
without impeding the draft. A cowl so formed is shewn at Figure 8.
a, a, a, are the inclined plates on the face of the cowl; these plates. are
bent down at their ends and fixed by rivets to the sides of the cowl as.
shewn, or they might be otherwise fixed in position. The cowl in other
respects is similar to cowls as now constructed, so that it is un-.
necessary to give here any description of it.
In witness whereof, I, the said George Hawksley, have hereunto
set my hand and seal, this Twenty-ninth day of July, in the
year of our Lord One thousand eight hundred and sixty-nine.