AN IMPROVED WIND-GUARD, SMOKE-PREVENTER, AND VENTILATOR
Year: 1880

page_text: PROVISIONAL SPECIFICATION left by Francis Thomas Bond and Frederick
Hodges at the Office of the Commissioners of Patents on the 16th February
1880.
FRANCIS THOMAS BOND, M.D., and FREDERICK HODGES, both of Gloucester, in
the County of Gloucester. "AN IMPROVED WIND-GUARD, SMOKE-PREVENTER, AND
VENTILATOR."
For the purpose of this Invention we take a hollow cylinder of any appropriate
size and material, and to the margin of one end thereof, which we shall hereafter
call the top, we apply a collar or flange of a width equal to about one half the
diameter of the cylinder, and bevelled downwards, so that the outer margin of
the flange shall be below the upper margin of the cylinder by a distance equal
to about one seventh of the diameter of the cylinder. Above the top of the
cylinder thus prepared we place a cap constructed in the following manner :- _We
take a flange or collar corresponding in the angle of its bevel to that which is
attached to the top of the cylinder, as above described, but having a larger diameter,
such, namely, that the smaller diameter of the upper flange shall be a little larger
than the diameter of the cylinder, and that its larger diameter shall bear the same
ratio to the smaller one that the larger diameter does to the smaller one in the lower
flange. The flange so formed is to be attached to the lower flange in such a way
that the smaller diameters of the two flanges shall be towards one another, and at
the same distance apart throughout, which distance shall be equal to about one
fifth of the diameter of the cylinder. The upper flange is supported in this position
by three or more uprights in the form of rods, tubes, or other convenient shape.
To this flange a third Hange is connected, having a reverse bevel to that of the
second flange, and of such a size and shape that the larger diameter shall be equal
to the smaller diameter of the second flange, whilst the smaller diameter shall bear
the same ratio to it that the smaller diameter does to the larger diameter of the
second flange. The two flanges are then to be connected together in such a way
that the larger diameter of the third flange shall be united to the smaller diameter
of the second flange, and that the margin of the smaller diameter shall project
upwards a little beyond the margin of the second flango. In the floor of the cavity
formed within the third flange we fix a circular plate, which may be either flat or
slightly coned or rounded on its upper surface, and is made of such a size that its
diameter shall slightly exceed that of the cylinder, and be less than that of the base

page_text: of the cap, thus leaving an annular space all round between its margin and the
lower margin of the cap. This plate we connect to the inner flange of the cap by
means of lugs or other convenient mode of attachment..
For the purpose of more clearly describing the nature of our Invention we have
appended hereto Drawings of the same, which we will now proceed to explain. Of
the said Drawings Figure 1 represents a vertical section of the apparatus made
down through the centro of the cylinder; Figure 2 is a perspective view of the
same, looked at from above; Figure 3 is an elevation. In all the Figures the same
letters indicate corresponding parts.
In these Figures A is the cylinder, to which is attached the bevelled flange B, B,
Above the cylinder is fixed the cap, with its outer bevelled flange C, C, and its
inner bevelled flange D, D. In the interior of the cap is the circular plate E, which
is attached to the inner flange D, D, by the lugs G, G. The cap is supported on the
flanged margin of the cylinder B, B, by means of the uprights F, F.
The action of the wind guard thus constructed is as follows:-When placed on the
top of a chimney or in any position in which it is exposed to the action of the wind
the latter, as it passes over the mouth of the cylinder, and between it and the
horizontal plate E, entangles the air in the mouth of the cylinder, and carries it
with it, thus creating a tendency to a vacuum in the cylinder, which causes the air
beneath to rise to supply the place of that which is carried away from the mouth,
and thus creates an upward current in the cylinder. The flanges C and D serve
to collect and concentrate the wind, and so to increase the force of the current
which passes over the mouth of the cylinder A. Should the direction of the wind
be not perfectly horizontal, but at an angle with the horizon in the upward
direction, it will strike the under surface of the plate E, and be thereby deflected
horizontally across the mouth of the cylinder. Should its direction be downwards
so much of it as strikes the upper surface of the plate E will be compelled to pass
between the border of this plate and the base of the flange D, and as it thus passes
in a cylindrical current obliquely downwards over the margin of the flange B it will
entangle the air on the surface and margin of this flange, and will carry it with it,
and so produce an upward current in the cylinder. In this way a current of air
blowing vertically downwards on to the upper surface of the wind guard will cause
an ascension of air in the cylinder beneath it.
We are aware that results of a somewhat similar kind may be obtained from
other contrivances of a different form froin that described above, but we have
satisfied ourselves that the best results are obtained from the arrangement con-
structed as we have described, and that it is also simpler and better adapted for
general use than any other with which we are acquainted.