IMPROVEMENTS IN GUARDS OR APPARATUS APPLICABLE TO CHIMNEYS FÓR THE PREVENTION OF DOWN DRAUGHT
Year: 1869

page_text: LETTERS PÅTENT to Walter Blundell, of No. 177, Upper Thames
Street, in the City of London, Gentleman, for the Invention of
"IMPROVEMENTS IN GUARDS OR APPARATUS APPLICABLE TO CHIMNEYS FÓR THE
PREVENTION OF DOWN DRAUGHT.”
Sealed the 3rd August 1869, and dated the 5th February 1869.
PROVISIONAL SPECIFICATION left by the said Walter Blundell at
the Office of the Commissioners of Patents, with his Petition, on
the 5th February 1869.
I, WALTER BLUNDELL, of No. 177, Upper Thames Street, in the
City of London, Gentleman, do hereby declare the nature of the said
Invention for "IMPROVEMENTS IN GUARDS OR APPARATUS APPLICABIN TO
CHIMNEYS FOR THE PREVENTION OF DOWN DRAUGHT," to be as follows i—
This Invention has for its object improvements in guards or apparatus
applicable to chimneys for the prevention of down draught, and consists
in a peculiar combination of guard or casing, flaps or louvre pieces, and
plates or feathers arranged as herein-after described so as to regulate

page_text: the opening and closing of suitable exit apertures for the smoke o
vitiated air, according to the direction of the wind. The guard or casing
which is to be placed on the chimney top in the usual manner, is made
of rectangular or other suitable cross section, and covered at its top by a
suitable cap. Its sides by preference at their upper parts are formed
with suitable openings, the area of the opening or combined total area
of the openings (as the case may be) at each side of the guard or casing
being equal to the cross sectional area of the guard or casing itself.
Each opening is provided with a flap or louvre piece working hori
zontally on pivots or centres in such manner that the upper part of the
flap or louvre piece when it is closed shall slightly overlap the inner
edge of the upper part of its opening, while the lower part of the flap
or louvre piece, in the same position, in like manner overlaps the outer
part of the lower edge of the opening. Each flap or louvre piece is so
balanced by a weight or other suitable means as to stand at an angle
when at rest, thus leaving its opening clear for the escape of smoke or
vitiated air, but so nevertheless that the slightest current of air from
without shall have the effect of causing it to close its opening. In the
corners of the guard or casing I likewise form slits or openings provided
with vertical plates or feathers working on suitable pivots or centres, so
that their inner edges project somewhat into the interior of the guard
or casing, their outer edges in like manner projecting outward, and
being by preference corrugated or equivalently formed so that the wind
shall more readily actuate them. The inner edge of each of these
vertical plates or feathers projects a little beyond the upper edges of the
horizontal flaps or louvre pieces at each side of it, in such manner that
the action of the wind upon the outer parts of the vertical plates in
certain directions shall have the effect of causing them to change the
position of the horizontal flaps so as to close the opening or openings
at the side of the guard or casing towards which the wind is blowing,
and thus prevent the down draught and consequent rush of smoke into
the apartment from which so much inconvenience ordinarily arises.
Should the wind be striking simultaneously against any two sides of the
guard or casing its effect will be to close the horizontal flaps at those
two sides, leaving the flaps at the other two sides open for the escape
of smoke.

page_text: on the 4th August 1869.
TO ALL TO WHOM THESE PRESENTS SHALL COME, I, WALTER
BLUNDELL, of No. 177, Upper Thames Street, in the City of London,
Gentleman, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Fifth day of February, in the year
of our Lord One thousand eight hundred and sixty-nine, in the
thirty-third year of Her reign, did, for Herself, Her heirs and suc-
cessors, give and grant unto me, the said Walter Blundell, Her
special licence that I, the said Walter Blundell, my executors, admi-
nistrators, and assigns, or such others as I, the said Walter Blundell,
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 GUARDS OR APPARATUS APPLICABLE TO CHIMNEYS FOR THE PRE-
VENTION OF DOWN DRAUGHT," upon the condition (amongst others) that I,
the said Walter Blundell, my executors or administrators, by an instru-
ment 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 Walter Blundell, 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, reference being had to the accom-

page_text: and consists in a peculiar combination in guards or casings of flaps or
louvre pieces, and plates or feathers arranged as herein-after described
so as to regulate the opening and closing of suitable exit apertures for
the smoke or vitiated air, according to the direction of the wind.
(Fig. 1) is a vertical section, and (Fig. 2) a transverse section on
the line A, B, Fig. 1, of the apparatus as applied to a chimney.
The guard or casing a, which is to be placed on the chimney top in
the usual manner, is in this case made rectangular in cross section and
covered at its top by a suitable cap 6. The sides at their upper parts
are formed with openings c, c, .c, the combined total area of the
openings at each side of the guard or casing being equal to the
cross sectional area of the guard or casing itself. Each opening is
provided with a flap or louvre piece d, working horizontally on pivots or
centres, in such manner that the upper part of the flap or louvre piece
when it is closed shall slightly overlap the inner edge of the upper
part of its opening, while the lower part of the flap or louvre piece in
the same position in like manner overlaps the outer part of the lower
edge of the openings. Each flap or louvre piece is so balanced by a
weight d', as shown (or by other suitable means), as to stand at an angle
when at rest, thus leaving its opening clear for the escape of smoke or
vitiated air, but so nevertheless that the slightest current of air from
without shall have the effect of causing it to close its opening. In the
corners of the guard or casing I likewise form slits or openings provided
with vertical plates or feathers e, e, working on suitable pivots or
_centres f, f, so that their inner edges project somewhat into the interior
of the guard or casing, their outer edges in like manner projecting
outward, and being by preference corrugated, as shown in Fig. 2, or
equivalently formed so that the wind shall more readily actuate them.
The inner edges of each of these vertical plates or feathers projects, as
will be seen on reference to the Drawing, a little beyond the upper
edges of the horizontal flaps or louvre pieces at each side of it, in such
manner that the action of the wind upon the outer parts of the vertical
plates in any direction shall have the effect of causing them to change
the position of the horizontal flaps so as to close the openings at the
side or sides of the guard or casing towards which the wind is blowing,
and thus prevent the down draught and consequent rush of smoke, into
the apartment, from which down draught so much inconvenience

page_text: ordinarily arises. Should the wind be striking simultaneously against
any two sides of the guard or casing its effect will be to close the hori-
zontal flaps at those two sides, leaving the flaps at the other two sides
open for the escape of smoke or vitiated air.
In some cases it may be found convenient to alter the form of the
cross section of the guard or casing, as also to make it with only one or
two openings at each side or with a greater number of openings than I
have shown in the accompanying Drawing.
(Fig. 8) is a front view, (Fig. 4) a side section on the line C, D, of
(Fig. 3), and (Fig. 5) a perspective view shewing another modification
of the combination of guard or casing, flaps or louvre pieces, plates or
feathers arranged so as to regulate the opening and closing of aper-
tures for ventilating purposes according to my Invention; the plates
or feathers are not shown in Fig. 5.
a is the guard or casing, which is open at its back part a¹
so that its interior communicates with the interior of the building
or chamber from which the vitiated air is to be withdrawn. The
cap in this arrangement consists of a flat plate fitted into the top
of the casing at a³, c is the opening, which is of a tapering form
and is provided with a number of corresponding flaps or louvre
pieces d slightly overlapping one another, as shown; e, e, are the
vertical plates or feathers working on pivots or centres so that their
inner edges project somewhat into the interior of the guard or casing,
while their outer edges in like manner project outwards, as shown, so
that the action of the wind upon the outer parts shall have the effect of
causing them to change the position of the horizontal flaps or louvre
pieces, so as to prevent the great rush of air and consequent draught
in the apartment,
Having now described the nature of my Invention, and in what
manner the same is to be performed, I would have it understood that
I do not confine myself to the exact forms shewn in the Drawings,
as they admit of being variously modified to suit the requirements of
the situations in which my Invention may be applied. I would
also state that I do not claim any of the parts separately, but that
what I do claim is, the combination and arrangement in guards or
casings of flaps or louvre pieces, and plates or feathers, arranged and

page_text: rating substantially as nerein-peiore described for the purposes
.specified.
In witness whereof, I, the said Walter Blundell, have hereunto
set my hand and scal, this Twenty-ninth day of July, in the
year of our Lord One thousand eight hundred and sixty-nine.
1