IMPROVEMENTS IN ROTARY FANS FOR VENTILATING OR OTHER PURPOSES
Year: 1885

page_text: :
I, WILLIAM ROBERT LAKE, of the firm of Haseltine, Lake & Co, Patent Agents,
Southampton Buildings, in the County of Middlesex, do hereby declare the nature
of my invention for "IMPROVEMENTS IN ROTARY FANS FOR VENTILATING OR
OTHER PURPOSES" and in what manner the same is to be performed, to be
particularly described and ascertained in and by the following statement :-
This invention relates to that class of rotary fans, for forcing or exhausting air,
in which a current is produced in a direction at right angles to that of the motion
of the blades of the fan; the latter being mounted on a rotary shaft and arranged
within a suitable casing or air passage.
The invention consists in the special formation of the blades of the fan, and in
their peculiar arrangement upon a rotary shaft, which will be hereinafter described.
In the accompanying drawing.
Figure 1 is a front elevation of the wheel or fan when used as an exhauster.
Figure 2 is, a rear elevation of the same.
Figure 3 is an outline showing the manner of forming and arranging the blades.
Figure 4 is a rear elevation showing the back. with the discharge openings
contracted.
Figure 5 is a vertical section drawn to a reduced scale.
A represents the hub or centre; B, the fan or blade portion; and O, the opening
in which the wheel or fan is located. D is the shaft on which the hub A is
mounted; E, E are boxes supporting the shaft D; F is a bar on which the boxes
are secured; and G is a brace or support for the bar F.
The hub A may be made solid as shown, or it may be made of a band with end
pieces, or in any other suitable manner, and its diameter depends upon the diameter
of the wheel, the larger the wheel, the greater being the diameter of the hub.
This hub is keyed or otherwise suitably secured to a shaft D, on which shaft is a
pulley wheel D¹, by means of which and a belt D' or other driving device, the
shaft can be revolved to revolve the wheel or fan.
The acting portion of the wheel or fan B is formed of a series of wings or
blades a, the inner ends a¹¹ of which are bent around and secured in any suitable
°

page_text: manner to the hub A; and the bend of the wings or blades a is one which projects
their forward or receiving edges so as to overhang the plane of the hub or centre as
shown. The back of the acting portion is formed of a spider so as to leave a series
of openings extending from near the periphery of the hub to the periphery of the
circumference of the back, to coincide with the openings between the blades or
wings.
The arms 6 of the spider for a small wheel may be formed of the same piece of
material as the wings or blades, as shown in Figure 3, the material being cut out
to leave openings as shown in said Figure 3, the arms b of the spider being secured
at their inner ends 6 in any suitable manner to the hub, while their outer ends b¹
form a connection to the wings a, the wings being cut, as shown in Figure 3, and
being bent or curved around as there shown, to have their inner ends lap on and
be secured to the hub. The spider may be formed of an independent piece as
shown in Figures 4 and 5, in which case the outer ends of the wings are turned
down and riveted, or otherwise secured to the rim or wings a¹ of the spider arms,
as shown in Figure 5, the inner ends of the spider arms being continuous with the
centre to which the hub A may be bolted, or otherwise secured.
When the spider is formed as shown in Figures 1 and 2 a greater area of
opening is left than when the spider is formed, as shown in Figure 4, and, if·
desired, the wheel might be formed as shown in Figure 2 and strips be secured to
the rear face to contract the openings, the object being to increase and decrease the
amount of discharge to suit the capacity of the wheel or the degree of exhaust
required.
The wings or blades being curved, as shown, it will be seen that their peri-
pheries c, at the front edge project beyond the actual periphery formed by the rear
face; thereby increasing the diameter of the wheel, the difference between the
circle of the projecting portion c, and the circle of the rear, thus increasing largely
the capacity of the wheel.
The curvature of the wings or blades in the manner shown causes their bent
edge to overlap the rear edge of the preceding wing or blade, forming a passage d'
between the respective wings, which passage decreases in size as it extends
rearward. The passage d thus formed between each two wings or blades extends
the entire distance from the top to the bottom of the said wings or blades
diminishing towards the rear, but leaving an unobstructed passage and one which
will receive air for its entire length and discharge the air'in the same manner, thus
preventing any vacuum around the hub and ensuring an increased capacity for
discharge.
The curving of the wings or blades as shown and described forms buckets by
which the wheel can be as readily used for a force fan as for an exhaust fan, the
shape of the buckets being such. that they will as readily receive and discharge
from the rear as from the front, owing to the divergence produced by bending
them in the manner described. To change the fan from an exhaust to a force fan
all that is necessary to be done is to cross the belt, if a belt is used for driving, or
to reverse the driving power giving the fan a reverse rotation.
The rear edge of the opening in the back or spider coincides in curvature with
the curvature of the blade or wing, and the rear edge of the blade or wing is
secured by rivetting, brazing, or in any other suitable manner, to the rear edge of
the opening with which it coincides. The wings or blades, it will be seen, have a
gradual rearwardly inclined pitch with their lower ends running parallel¨and
rearwardly to the plane of the circumference of the hub, and their upper ends with
a rearwardly and inward pitch producing a wide mouth or opening for the
receiving side, which opening contracts gradually towards the 'delivery side
whereby the air caught by the front side will be drawn in for the entire size of the
opening with a free discharge from the top to the bottom. By giving the receiving
edge a curved projection forward of the plane of the forward end of the hub or
centre, which projection increases gradually in width as it rises from the hub or
'centre to a line in a plane with the forward end of the hub or centre, it will be

page_text: seen that a greater receiving capacity is provided than if the forward edges of the
wings were on a straight diagonal line from the hub to the periphery of the wings.
The diameter for the back or rear face of the wheel being smaller than the
actual diameter formed by the outer ends of the wings or blades, enables the fan
to be set in an opening the diameter of which corresponds to the diameter of the
rear or back, thus enabling the fan to be placed in position with the outer ends of
the wings or blades beyond the circumference of the opening thereby increasing
the capacity of the wheel or fan.
Having now particularly described and ascertained the nature of the said
invention, and in what manner the same is to be performed, as communicated
to me by my foreign correspondent I declare that what I claim is
First. The ventilator fan or wheel, composed of the hub A. and the wings a, the
outer edges, of the wings being connected with each other and describing the
periphery of the rear face of the wheel, in the plane of said face, and the said
wings being curved, substantially as shown, from said point to the hub with the
longest curve on the receiving face and the shortest on the rear face of the wheel,
the inner end of the blades being secured to the hub obliquely to the axis thereof,
whereby the wings will project beyond the periphery of the rear face of the wheel
and thereby increase the diameter of the wheel adjacent to such face, substantially
as described.
Second. The ventilator fan or wheel composed of the hub A and the wings a,
the outer ends of the wings being connected with each other and describing the
periphery of the rear face of the wheel in the plane of said face and the wings
being curved from said point to the hub obliquely to the axis of the hub and secured
to the latter obliquely to its axis, the front edge of one wing overlapping the rear
edge of the preceding wing to form a passage d from the periphery of the wheel to
its hub, decreasing in size from the front to the rear face of the wheel, substantially
as described.
Dated this 97th dow of Databou 1005