IMPROVEMENTS IN CHIMNEY COWLS
Year: 1868

page_text: LETTERS PATENT to Carl Windhausen and Heinrich Büssing, both
of the City of Brunswick, Germany, Engineers, for the Invention
of "IMPROVEMENTS IN CHIMNEY COWLS."
Sealed the 20th November 1868, and dated the 23rd May 1868..
PROVISIONAL SPECIFICATION left by the said Carl Windhausen
and Heinrich Büssing at the Office of the Commissioners of.
Patents, with their Petition, on the 23rd May 1868.
We, CARL. WINDHAUSEN and HEINRICH BÜSSING, both, of the City-
of Brunswick, Germany, Engineers, do hereby declare the nature of
the said Invention. for "IMPROVEMENTS IN CHIMNEY. COWLS," to be. as.
follows:-
The chimney cowls hitherto used for protecting the draught of
chimneys from the influence of wind, rain, and the rays of the sun do.
not answer sufficiently well. Those chimney cowls having moveable.
The
parts easily get out of order and therefore become unreliable.
fixed chimney tops, that is to say such as have no moveable parts, have
likewise several defects. Either they have horizontal, conical, or
concave coverings which oppose from above the natural efflux,of, the.

page_text: smoke, or their surfaces for turning off the wind are so constructed that
the column of smoke is bent in a disadvantageous manner or the
sectional area of the column of smoke as it issues from the chimney is
diminished by the current of air and a lessening in the velocity of the
smoke results, or their construction is not such that every wind, even
that descending vertically upon them, is not only made harmless but
even conducive to the draught; besides all the known chimney cowls
have decided defects with respect to stability and ornamental appearance,
and not only render the cleaning of the chimney difficult, but can
themselves only be cleaned with difficulty if at all.
Considering these facts we have invented a new chimney cowl called
from its principle "the deflector" in which all the defects of the known
chimney cowls are done away with, being hereby distinguished from the
latter, first, it has no movable parts; secondly, it has no external lid;
thirdly, it allows the column of smoke to issue without injurious
bendings and without reduction of its sectional area; fourthly, under
all circumstances it renders the entrance of wind, rain, and the sun's
rays impossible; fifthly, it compels every wind, even that descending
vertically upon it, to conduce to the draught in the chimney; sixthly,
it possesses an external form which is ornamental and can be easily
adapted to every style of architecture; seventhly, it does not render the
cleaning of the chimney difficult and can itself be cleaned with ease.
The deflector proper which assists the draught and keeps off the wind
is of a circular form, the exterior surface of which is constructed of such
a curve that a tangent drawn to it through one of its ends is parallel
to the axis of the vertical column of smoke. The velocity of the wind
leaving the surface in this direction being at a maximum, the column
of smoke is not opposed in its tendency to rise by the draught of wind,
but rather assisted.. A hollow cone with a slightly convex surface
is hung in the axis of the smoke pipe. When the chimney is to be
cleaned this cone can be taken out and put in again, its greatest diameter
being about half an inch larger than the diameter of the smoke pipe.
The cone stands with its apex vertically over the axis of and in the
same plane as the end of the smoke pipe. The surface of the surrounding
cover of the apparatus is parallel to that of the inner deflector. The
area of the annular space between the cover and the smoke pipe taken
on the plane of its end must be nearly equal to twice the sectional
area of the smoke pipe. An open screen is constructed according to the

page_text: same general laws as govern the inner deflector and surrounding cover.
The sectional arca of its upper orifice is equal to the area of the annular
space between the upper part of the cone and the surrounding cover.
The height of the upper edge of the screen above the cone and the
surrounding cover is determined by bringing the terminating points of
the upper edge of the screen to touch two tangents which are drawn
up the side of the cone in the plane of its vertical section from the
upper edge of the smoke pipe to the upper edge of the screen. A pipe
serves to carry off the water collected in the cone. All parts of the
deflector are not necessarily of a circular form, they may be angular,
octagonal, or polygonal, and the inner deflector and surrounding casing
may be connected by vertical, oblique, or curved ribs. The apparatus
may be manufactured of metal or earthenware, and must be provided
with a durable coat of paint, by preference black.
SPECIFICATION in pursuance of the conditions of the Letters Patent
filed by the said Carl Windhausen and Heinrich Büssing in the
Great Seal Patent Office on the 21st November 1868.
TO ALL TO WHOM THESE PRESENTS SHALL COME, we, CARL
WINDHAUSEN and HEINRICH BÜSSING, both of the City of Brunswick,
Germany, send greeting.
WHEREAS Her most Excellent Majesty Queen Victoria, by Her
Letters Patent, bearing date the Twenty-third day of May, in the year
of our Lord One thousand eight hundred and sixty-eight, in the thirty-
first year of Her reign, did, for Herself, Her heirs and successors,
give and grant unto us, the said Carl Windhausen and Heinrich
Büssing, Her special license that we, the said Carl Windhausen and
Heinrich Büssing, our executors, administrators, and assigns, or such
others as we, the said Carl Windhausen and Heinrich Büssing, our
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, exercisc,
and vend, within the United Kingdom of Great Britain and Ireland, the
Channel Islands, and Isle of Man, an Invention for "IMPROVEMENTS
IN CHIMNEY COWLS," upon the condition (amongst others) that we, the

page_text: said Carl Windhausen and Heinrich Büssing, our executors or adminis-
trators, by an instrument in writing under our, 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 we, the said Carl Windhausen and Heinrich
Büssing, do hereby declare the nature of our said Invention, and in
what manner the same is to be performed, to be particularly described
and ascertained in and by the following statement :-
Many attempts have hitherto been made to construct a chimney top
'or cowl to prevent down draft and the entrance of wind, rain, or the
rays of the sun into the flues, and to cause a draught in chimneys
situated in exposed positions, but all such chimney tops or cowls have
been more or less open to objections, those with revolving parts being
liable to stick fast and to become deranged, others constructed with
external lids or coverings have impeded the egress of the smoke; and
again some have been so formed as to cause the smoke to pursue a
tortuous course, and thus its velocity in escaping has been lessened and
the draught interfered with, whilst many have been so complicated as
to render the cleaning of the flues difficult and in some cases altogether
.impracticable.
Taking all these points into consideration we have invented a novel
*construction of chimney top or cowl, which we call the deflector,
because it is constructed on a peculiar principle which deflects the
wind or rain, and is not open to any of the objections herein-before
mentioned, and we claim for our Invention the following advantages:―
1st, that it has no moveable or revolving parts; 2nd, that it has no
external lid or covering; 3rd, that it allows the column of smoke to
pass through without tortuous and injurious bendings and without
reducing its sectional area by a current of air surrounding such column
of smoke; 4th, that under all circumstances it renders the entrance
of wind, rain, and the rays of the sun into the flues impossible; 5th,
that its peculiar internal form compels wind coming from any quarter,
and even that descending vertically upon it, to conduce to the draught
in the chimney; 6th, that its external form is ornamental yet rigid and
strong, and can easily be adopted to any style of architecture; 7th, that

page_text: it does not prevent the easy cleaning of the flues, and can itself be
cleaned with facility.
In order that this our said Invention may be the more readily scen
and understood, we have hereunto annexed a Drawing of our improved
chimney top or cowl, drawn to a scale of about quarter size, and we
will now proceed to describe its construction by reference to the letters
marked upon the Drawing.
Fig. 1 is an external elevation, and Fig. 2 is a sectional elevation of
our improved chimney top or cowl, the same letters of reference being
used in both views to denote similar parts, A is what may be termed
the deflector proper, which is an annular casing surrounding the base
or smoke pipe B, such casing being constructed with a concave or
curvilinear external surface, so formed in order that tangent lines
drawn from its upper extremities would be parallel to what may be
termed the axis or central line of the flue, and thus any wind striking
or coming in contact with the surface of such casing from any quarter
would be compelled to leave such surface in the direction of such
tangent lines, and thereby, instead of opposing the upward current of
the smoke, materially assists it in its course; C is an outer casing
surrounding the deflector A and partially covering such deflector, as
illustrated, by being extended above and below the mouth of the smoke
pipe B or top of the deflector A, such outer casing being supported
upon open or lattice work D, so as to allow the wind from any quarter
to enter through such lattice work and thus assist the upward current
of smoke by the deflecting action of the deflector A. This outer casing
C, we prefer to construct as nearly parallel in its curvilinear annular
surface to the deflector as possible and of such diameter as to allow an
annular space of twice the sectional area of the smoke pipe round the
base of the inverted cone herein-after described. E is a hollow cone
or conical body with a slightly convex external surface, fitting into
brackets or ribs secured to the outer casing C, and such cone is
situated in the axis or central line of the smoke passage and at such a
height above the smoke pipe as to have its upper rim in the same
horizontal plane as the upper rim or extremity of the outer casing C.
This conc may be lifted out of its seating when it is necessary to clean
the chimney, and is provided with a pipe F to carry off any rain
which would in its absence enter the flue, and serves also to cause the
wind entering vertically from the top to be deflected again into the
open air, which wind generally escapes through the side openings

page_text: or lattice work D. This cone also prevents the rays of the sun from
entering the flue and heating one side of such flue, so as to cause
counter currents, and thereby interfere with the draught. The apex of
the cone is arranged to occupy the same horizontal plane as the mouth
of the smoke pipe B, whilst its largest diameter or base is a little
greater (say half an inch) than the mouth of the smoke pipe. The
height or length of the cone E will be regulated by the diameter or
sectional area of the smoke pipe, as the smaller the diameter or sectional
area of such smoke pipe the longer the conc and outer casing should
be, taking care to have the base and apex of the conc in the same
horizontal planès as have been herein-before described. G is an open
annular screen constructed of concave curvilinear external form, the
lower extremity of which is a little lower than the top of the external or
outer casing C, whilst its upper edge extends above such outer casing,
as illustrated, the precise height of such scrcen being dertermined by
drawing straight lines from the top of the smoke pipe past the sides of
the cone, so as just to touch its base and be extended upwards, until
such straight lines intersect the annular concave curve of the screen,
which intersecting point is the proper height for the screen. These
lines are shewn dotted in the Drawing marked d and v. The sectional
area of the upper orifice or mouth of such screen should be equal to the
annular space surrounding the base of the cone E. The arrows in
Fig. 2 denote the direction in which the wind may enter the chimney
top or cowl to promote the upward current of the smoke, and it will be
readily apparent that the smoke escapes from the flue round the outside
of the cone E and is materially assisted in its egress by the action of
any wind blowing from any quarter, by the deflecting action of the
curvilinear surface of the various parts of the chimney top or cowl,
which deflecting surfaces render the admission of wind, even that
descending vertically, not only harmless, but even conducive to the
draught.
We wish it to be distinctly understood that we do not confine
ourselves to the annular or cylindrical form in constructing our
improved chimney top or cowl, as the principle is equally applicable
in an angular form, and by preference may be constructed in an
octagonal or polygonal shape, nor do we confine ourselves to any
material, as it may be made of sheet or cast metal, or of carthenware,
terra cotta, or other material of which such articles are usually
constructed.

page_text: Our improved chimney top or cowl is found to be usefull as a
ventilator for buildings, ships, and railway carriages, and forms an
excellent funnel for locomotive, portable, stationary, and marine steam
boilers.
Having thus particularly described and ascertained the nature of this
our said Invention, together with the best means with which we are
acquainted for carrying the same into practical effect, we wish it to be
understood that we do not confine ourselves to the precise details,
relative proportions or dimensions, as the same may be considerably
varied, without departing from the Invention; but what we do claim
is, constructing chimney tops or cowls with the peculiar deflecting
surfaces, together with the application of the cone, as and for tho
purposes described and illustrated in the accompanying Drawing or
any mere modification of the same.
In witness whercof, we, the said Carl Windhausen and Heinrich
Büssing, have hereunto set our hands and affixed our seals,
this Fifteenth day of November, in the year of our Lord One
thousand eight hundred and sixty-cight.
CARL WINDHAUSEN. (L.S.)
HEINRICH BÜSSING. (L.S.)