An Improved Chimney Cowl, also Applicable as an Exhaust Ventilator.
Year: 1888

page_text: COMPLETE SPECIFICATION.
An Improved Chimney Cowl, also Applicable as an Exhaust
Ventilator.
I HERBERT LAWRANCE of 22 Malmesbury Road Bow in the County of Middlesex
Carpenter do hereby declare the nature of this invention and in what manner the
same is to be performed, to be particularly described and ascertained in and by
the following statement :-
The object of this invention is to produce an economical, simple and efficient
chimney cowl, which shall be also applicable as an exhaust ventilator for mines, and
buildings, and for all purposes where an updraught is required.
The invention consists of a cylinder fitting tightly into the centre of and projecting
slightly beyond a disc. whose plane is at right angles to that of the cylinder. A second
dise is rigidly affixed to the projecting end of the cylinder by extension arins or any
other suitable device which will maintain the second disc in a plane parallel to the
plane of the first disc. The projecting part of the cylinder reaches about half way up
between the two discs.
When the wind blows between the discs it impinges against the projecting part of
the cylinder and plays across the top thereof, producing a partial vacuum and a
consequent suction or updraught in the chimney or ventilator to which the invention
may be attached. Hence the stronger the wind the stronger will be the updraught.
And in order that my invention may be fully understood and carried into practice
I will now proceed to describe the same with reference to the accompanying drawings
in which similar letters indicate corresponding parts in all the figures.
Fig. 1 is an elevation of the invention.
Fig. 2 is a plan on the line a a Fig 1; and,
Fig. 3 shews the invention as applied to an ordinary chimney.
The invention is preferably made of some kind of metal. The disc C has a circular
hole of a slightly smaller diameter than the outside diameter of the cylinder. The
disc is heated and passed over the cylinder, and on contraction is allowed to fit
tightly into a groove in the circumference of the cylinder. The cylinder has four or
any convenient number of extension arms D to which the second disc B is rigidly
affixed. But the invention may be constructed of any suitable material, and the

page_text: attachments made in any convenient way, provided that the discs B & C are rigidly
maintained in planes, which are perpendicular to the plane of the cylinder and that
the end E of the said cylinder projects beyond the disc and reaches about halfway
to the disc B as shewn in Fig. 1.
It is obvious that the invention is applicable not only as a chimney cowl but also
as an exhaust ventilator for mines and buildings and for all purposes where an
updraught is required.
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 1
claim is :-
The construction of a chimney cowl or exhaust ventilator, consisting of a cylinder,
one end of which extends half way between two parallel discs rigidly affixed
perpendicularly to the said cylinder substantially as and for the purpose-hereinbefore
set forth and illustrated in the accompanying drawings.
Dated this 1st day of March 1888.
CASTLE SMITH,
Invention Office,
54, Fleet Street, London, E.C.,
Agent for the Applicant.
CASTLE SMITH,
Invention Office,
54, Fleet Street, London, E.C.,
Agent for the Applicant.