Year: 1887

page_text: Date of Application, 29th Jan., 1887
Complete Left, 28th Oct., 1887
Complete Accepted, 29th Nov., 1887
I JOHN BIDDER of 12 Delahay Street Westminster in the county of Middlesex
Surveyor do hereby declare the nature of this invention to be as follows:-
The object of my invention is to produce a chimney cowl that shall be extremely
efficient. in inducing an updraught in the chimney that shall entirely prevent any
down draught therein and that shall very easily be actuated and this cowl will
obviously be suitable for use as an exhaust ventilator.
To carry out this object I fit a cylindrical metal or other cap on the top of the
chimney or ventilating shaft with a closed top and near this top I make therein a
series of vertical apertures. A vertical spindle passes through the closed top and is
mounted on a suitable bracket near the bottom of the cap on which spindle is secured
below the vertical apertures a fan consisting of a number of inclined blades the
peripheries of which closely approximate to the walls of the cap. Above the cap is
mounted by any suitable socket and spindle a revolving cowl which extends a con-
venient distance above the top of the cap and there consists of a central cylinder on
the sides of which are secured a series of vanes preferably curved in horizontal
section or set at a proper tangential angle to the cylinder to ensure that this cowl
shall be revolved in the proper direction by the action of the passing wind outside.
These vanes or the outer portions of the same are continued downwards outside the
cap to about the level of the bottoms of the vertical apertures aforesaid.
bottom of the central cylinder of the cowl and all round inside the same are formed a
series of teeth by which through the intervention of one or more toothed wheels
mounted on the top of the cap the vertical spindle aforesaid is caused to revolve at
the required speed.
Near the
Thus when the cowl is caused to revolve by the action of the passing wind the
vertical spindle and the fan thereon are also caused to revolve and the action of this

page_text: fan is to induce a strong draught up the chimney or the ventilating shaft which is
discharged through the vertical apertures in the cap and a down draught is entirely
prevented.
In large ventilators or when required any other suitable or convenient power may
be used to cause the aforesaid revolution.
In some cases and especially when this apparatus is used on a chimney a light
frame or wire may be attached to the vertical spindle and to the fan or one of the
blades thereof if necessary which will closely approximate to the walls of the cap and
prevent the deposit thereon or in the vertical apertures of any soot or other undesirable
substance and a small door may also be fitted in the walls of the cap to allow of access
to the fan.
D
}
1005

page_text: 1 JOHN BIDDER of 12 Delahay Street Westminster in the county of Middlesex
Surveyor 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 my invention is to produce a chimney cowl that shall be extremely
efficient in inducing an updraught in the chimney that shall entirely prevent any
down draught and that shall very easily be actuated and this cowl will obviously be
suitable for use as an exhaust ventilator.
In the accompanying drawing I have shewn a most convenient and suitable form
and style of this my chimney cowl or ventilator wherein Figure 1 is a vertical section
of the same. Figure 2 is an horizontal section thereof taken at a a in Figure 1.
Figure 3 is an horizontal section thereof taken at b b in Figure 1. Figure 4 is an
horizontal section thereof taken at c c in Figure 1 and Figure 5 is an horizontal
section of part thereof on an enlarged scale taken at d d in Figure 1.
I fit a cylindrical metal or other cap A on the top of the chimney or ventilating
shaft with a closed top and near this closed top thereof I make in the walls of the
cap A a series of vertical apertures B. A central vertical spindle C passes through
the closed top of the cap A and is mounted below on a suitable bracket D near the
bottom of the same on which spindle is secured below the apertures B a fan E
consisting of a number of inclined blades the peripheries of which closely approximate
to the walls of the cap A. On the top of the cap A is fitted a bracket F in and by
which the upper end of the spindle C can conveniently be held as shewn and on this
bracket F is formed a socket in which is mounted a central vertical spindle H whereby
a revolving cowl is supported. This cowl extends a convenient distance above the
top of the cap A and consists of a central cylinder 1 supported on and by the spindle H
and on the sides of the cylinder I are secured a series of vertical vanes K which are
preferably curved in horizontal section as shewn in Figure 2 or may be set at a proper
tangential angle to the cylinder to ensure that this cowl shall be revolved in the
proper direction by the action of the passing wind outside. These vanes K or the
outer portions of the same are continued downwards outside the cap A as shewn at K'
to about the level of the bottoms of the apertures B and to or with these continua-
tions K' are fitted or formed the guards L which form parts of the circumference of
a circle having the same centre as but a larger radius than the cap A in horizontal
section as shewn in Figure 2 and these guards L are preferably of the same length
as the continuations K and thus as the cowl revolves and these guards L pass
rapidly before the apertures B while no impediment is offered to the exit of air
through these apertures the outside wind is prevented access thereto. Near the
bottom of the central cylinder I and all round inside the same are formed a series of
teeth M. by which through the intervention of one or more toothed wheels N mounted
on the top of the cap A and under the bracket F the vertical spindle C is caused to

page_text: revolve when the cowl is revolved and these wheels N are preferably so arranged that
this spindle C and the fan E thereon are caused to revolve at a speed greatly
increased above that of the cowl and the central cylinder I thereof.
Thus when the cowl is caused to revolve by the action of the passing wind the
spindle and the fan thereon are also caused to revolve and the action of this fan is
to induce a strong draught up the chimney or the ventilating shaft which is discharged
through the apertures in the cap and a down draught is entirely prevented.
In large ventilators or when required any other suitable or convenient power may
be used to cause the aforesaid revolution of the fan.
In some cases and especially when this apparatus is used on a chimney a light
frame or a wire P may be attached to the spindle C and to the fan E or to one of the
blades thereof if necessary which will closely approximate to the walls of the cap A
and in its revolution prevent the deposit thereon or in the apertures B of any soot or
other undesirable substance and a small door R may also be fitted in the walls of the
cap A to allow of access to the fan E and to the interior of the cap A below the same
for purposes of cleaning or repair or otherwise.
I have thus described and I have shewn in the accompanying drawing very suitable
forms and proportions of my chimney cowl or ventilator and of the several parts
thereof and also very convenient methods and details of constructing and fitting and
actuating the same but I do not limit myself thereto for this my chimney cowl or
ventilator and all the several parts thereof may be made of such shapes and pro-
portions and may be constructed and fitted and actuated in such a manner as may be
desirable in each particular case.
Having now particularly described and ascertained the nature of my said invention
and in what manner the same is to be performed 1 declare that what I claim is
The arrangement and combination of parts and appliances constituting my chimney
cowl or ventilator substantially as herein before set forth.