An Improved Chimney Cowl.
Year: 1895

page_text: An Improved Chimney Cowl.
I, JOSEPH MONIER, of No. 14, Rue Gustave-Courbet, Paris, in the Republic
of France, Contractor do hereby declare the nature of this invention to be as
follows:-
The object of the present application is an apparatus designed to be placed on
the top of a chimney of any kind for the purpose of augmenting the draught of the
said chimney in spite of wind and storms and consequently to prevent the smoke
and combustion gases from being blown down into the rooms below.
The apparatus is constructed of a given number of pieces placed one upon the
other on a metallic conical frame. Each of these pieces is composed of a portion
bent down and straight or helical supported upon pieces attached to uprights
forming the general framework. This cover has for its object to prevent down
draught and to cause a suction above the tube of the chimney assisting the
draught. Above the part first described and forming a part thereof or otherwise
is placed a curved collar which has for its object to guide the wind to bend round
without baffling the draught. This piece is supported by a little metallic cross-
bar. Above the part just described and at a given distance another similar
smaller piece is secured upon the bars. The same construction is continued up to
the point of junction of the frame at which place there may be placed a simple
hood or a revolving cowl of any kind preferably provided on the windward side
with a turned down collar.
It is obvious that these various pieces may be formed of various shapes, that is to
say either round, square, triangular, or otherwise, the metallic frame being
correspondingly shaped, they can also be formed of any suitable materials as for
instance of zinc, hammered iron, galvanised iron, steel plate and the like. The
combination of these pieces may be formed throughout of one single material or of
various materials.
1
SN
mhon 1805
I, JOSEPH MONIER, of No. 14, Rue Gustave-Courbet, Paris, in the Republic
of France, Contractor, 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:-
The apparatus entitled a "chimney cowl" has for its object to prevent chimneys
of all kinds from smoking. It is especially designed to be placed upon the tops of
chimneys which rise from the roofs; and it consists essentially of a certain number
of hoods or caps, variable in quantity according to the strength of the draught and
which are arranged one above the other and in a special manner with relation to
each other.

page_text: CONTO
.
form.
Figure 2 is a vertical section through the axis of Figure 1.
Figure 3 is a vertical section of the revolving piece by means of which any
chimney head may be covered instead of ending in the little fixed hood or cap
shown in Figures 1 and 2.
Figure 4 is also the vertical section of a simple chimney head in which the form
of the wings of the hoods is better adapted than in the shapes shewn in Figures 1
and 2 to guide and deflect the currents of air without motion.
Figure 5 is an elevation of a chimney head with three compound cowls grouped
the middle one being higher than the two others.
Figure 6 shows in vertical section the application of a cowl to a machine or
factory chimney.
A chimney cowl is formed of a given number of caps or hoods 1, 2, 3, 4 ... of
round or quadrangular form arranged in a series of decreasing size one above
another and at suitable intervals.
Each hood has a wing a the shape of which may vary, over which the wind
'blows and rises and it is supported by projections 661 fixed to arms cc connected
to one another so that they form an interior framework of conical or pyramidal
form fixed at its base to the chimney top S projecting from the roof T and into
which the chimney pot discharges or the chimney pots if more than one as is
I often the case.
The wing a of each hood is fitted to the body e of the same, the upper edge of
which is turned to form an overlap F. The lower edge g of this overlap is always
somewhat higher in respect to a horizontal lower section than the edge of the
wing a so as to be sheltered against the wind.
The parts being so arranged, let us assume that the wind blows in the direction
of the arrow v; the current of air will be divided by the edge h into two streams:
the lower one passing under the edge and flowing in the direction shown by the
arrow i into the embrasure A between the wing a and the side wall of the base S
which has been previously finished off smooth to assist the current of wind, the
said current tending to augment the draught in the direction of the arrow f;
the upper one passing along the upper side wall of the wing a rising in the
direction of the arrow to the commencement of the edge F in form of a reversed
hook, which directs the draught in the manner shown by the arrow all from which
it results that this inflected current effects aspiration especially around the lower
.part of the orifice A¹ by which the smoke escapes in the direction of the arrow f¹.
In the same manner the part divides the wind into two currents: the lower
one which is turned down by the action of the smoke escaping in the direction of
the arrow f' and by that of the air inflected in the direction of the arrow : the
other or upper current which blows along the upper wall of the wing a¹ and is
inflected by the margin F¹ and produces on the orifice A" the same aspirating
effect from above downwards which I have described as being effected at the
orifice A¹.
The same effects are realised at the upper parts of which the number and the
size vary according to the number of the chimney pots and the strength of
the draught. The final cowl No. 5 or m shown in Figures 1 and 2 can be replaced
by a mobile cowl Figure 3 provided with a weather vanej placed in the middle
plane of the two opposite orifices k land which takes the direction of the wind indicated
by the arrow v. The wind accordingly blows at the same time through the
opening and through the opening 7 sheltered by the wing n.
In Figure 4 the form alone of the wing a better adjusted to the body e is
changed; the action of the gaseous current which does not experience above this
wing any side draught or eddy is more active especially when the surface is fairly
smooth.
When the base S contains a great number of chimney pots and a powerfu
draught is required, it is preferable, in place of fixing above the same a single

page_text: apparatus which would necessarily consist of a great number of cowls, would
probably be too high and would offer a great resistance to the wind, to have in its
place, two, three, or more separate apparatuses.
Figure 5 shows one such construction, formed of three groups of cowls, the
middle one being preferably somewhat higher than the side apparatuses as being
more symmetrical and elegant.
The apparatus so arranged is moreover more substantial, more sightly, and offers
escape vents for the wind and for the emission of the smoke so as to produce a
vigorous draught no matter what the weather may be.
Figure 6 shows a large single chimney capped by an apparatus of my invention
and which is firmly fixed to the top of the chimney shaft.
Having now particularly described and ascertained the nature of my said inven-
tion, and in what manner the same is to be performed I declare that what I
claim is :-
1. In a chimney cowl apparatus, adapted to be placed on top of one or more
chimneys, to increase the draught, the similar cowls 1, 2, 3, of sufficient number
and of any desired size arranged with suitable intervening spaces one above
another, on supports bb... of a metal frame cc.... fixed to the chimney or
its top S around the chimney pots, the wings a a of each hood being in
adjustment with a piece e and the rim F of the said cowl under which curve the
wind is turned downwards, and exercises an aspiration on the peripheric orifice A'
and A opening between the said wings and the wall of the curved piece F whilst
the current of air passing under the rim discharges into the lower embrasure A
and assists the draught in the direction of the arrow f, the edge gg of each
of the bent pieces F being always placed a little above the edge of the corre-
sponding rim h¹ h¹¹
of the corresponding wing a¹ a
sheltered thereby.
.... 20 as to be
2. In a chimney cowl apparatus placed above one or more chimneys to assist the
draught and arranged substantially as set forth in Claim 1 the replacing of
the little fixed top cowl m by a mobile hood n with weather vanej provided with
two opposite draught openings of which the axis is placed in the plane of the
weather vane the one k above, the other / below.
3. In a chimney cowl apparatus placed over one or more chimneys to assist the
draught and arranged in the manner specified in Claims 1 and 2, the special
arrangement in which two, three, or more apparatuses are combined beside each
other so as to form instead of a single cowl apparatus, joined apparatuses, of the
same or of different heights.
Dated this 10th day of Tune 1000
W. P. THOMPSON & Co.,
322, High Holborn, London, W.C., Patent Agents for the Applicant.