Improvements in Exhaust Fans or Blowers.
Year: 1896

page_text: Date of Application, 8th Apr., 1896
Complete Specification Left, 8th Jan., 1897-Accepted, 20th Feb., 1897
PROVISIONAL SPECIFICATION.
[Communicated from abroad by THERON A. RICHARDS, of 75 Fulton Street,
New York, United States of America, Engineer.]
Improvements in Exhaust Fans or Blowers.
I, PHINEAS LAWRENCE, of 63, Farringdon Road, in the County of London,
Merchant, do hereby declare the nature of this invention to be as follows:-
This invention relates to improvements in exhaust fans or blowers, and it has for
its object to provide an apparatus for exhausting air from apartments, or for forcing
air into apartments for ventilating or industrial purposes. In the apparatus, about
to be described, an unobstructed discharge is obtained for the entire body. of air,
which is delivered uniformly from all the blades of the fan during the revolution:
of the fan-wheel, the air being continuously discharged towards the outlet of the
casing from all the blades simultaneously, during the revolution of the fan, so that
the blades are entirely relieved from the injurious effects of back pressure now
experienced in blowers, as ordinarily constructed. By this apparatus, a given
amount of work can be performed with much less expenditure of power than is
usually required for operating exhausters or blowers, as heretofore constructed,
besides which, the apparatus is practically noiseless in its operation, and will not
become obstructed by solid substances that may be drawn into it.
In a blower or exhauster constructed according to this invention, a fan-wheel-
having blades of regular diametrical pitch, carried by a large solid hub, or by a
series of spokes, is mounted to revolve within a casing, and a cup-shaped partition,
disc, or centre plate, is interposed between the outlet of this casing and the inner
central part of the fan wheel. The blades of said fan wheel are adjusted to revolve
between the inner surface of the casing, and close to the outer surface or annular
wall of the cup-shaped partition.
The inlet of the blower casing is directly in the rear of the wheel blades, and the
flow of the air takes place in a direction substantially parallel with the inner walls
of the blower-casing towards the outlet which is arranged centrally of the
apparatus.
The conformation of the wheel blades is such that the air is drawn or forced
through at the same rate at their inner edges as at their outer edges.
Dated this 8th day of April 1896.
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5ª Market Street, Nottingham,
Agent for the Applicant.
COMPLETE SPECIFICATION.
Improvements in Exhaust Fans or Blowers.
I, PHINEAS LAWRENCE, of 63, Farringdon Road, in the County of London,
Merchant, 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, reference being had to the accompanying drawings
and to the letters and figures marked thereon, that is to say :-
This invention relates to improvements in exhaust fans or blowers, and it has

page_text: for its object to provide an apparatus for exhausting air from apartments, or for
forcing air into apartments for ventilating or industrial purposes. In the apparatus
about to be described an unobstructed discharge is obtained for the entire body of
air which is delivered uniformly from all the blades of the fan during the revolution
of the fan-wheel, the air being coutinuously discharged towards the outlet of the
casing from all the blades simultaneously during the revolution of the fan, so that
the blades are entirely relieved from the injurious effects of back pressure now
experienced in blowers, as ordinarily constructed. By this apparatus, a given
amount of work can be performel with much less expenditure of power than is
usually required for operating exhausters or blowers, as heretofore constructed,
besides which the apparatus is practically noiseless in its operation, and will not
become obstructed by solid substances that may be drawn into.it.
In the accompanying drawings, which illustrate the invention,
Fig. 1 is a longitudinal vertical section of an apparatus embodying the
improvements.
Fig. 2 is a vertical section on the line a, a, of Fig. 1, and
Fig. 3 shews, to an enlarged scale, in plan, the hub of a fan wheel with a blade
arranged in connection therewith, as used in the apparatus.
Fig. 4 is a longitudinal vertical section, and 5 a vertical section on the line y, y,
of Fig. 4 shewing a modified form of the apparatus.
Throughout the drawings like letters of reference indicate similar parts.
A is the main frame in which the axle B is journalled, and to the one end of
which axle is secured the fan-wheel K. This wheel comprises a large solid hub k²
and blades k¹, k', having regular diametrical pitch, the same as given to the blades
of propeller wheels. Such pitch is best illustrated in Fig. 3. These blades may
be either riveted to, or cast integral with, the hub 2. Secured to the axle B, is
the driving pulley D which is arranged between two standards a, a, forming part
of the main supporting frame A, and each carrying, at its upper end, a bearing
for the axle B. E is the fan casing and H is a partition or centre plate arranged
between the inlet I and the outlet O of the fan casing. The partition H is cup-
shaped and of the same diameter as the hub of the fan, and the blades are made
to extend forward so as to have their inner edges revolve in close proximity to the
annular wall of said partition. The inlet I of the blower casing is directly in the
rear of the wheel blades and the flow of air takes place in a direction substantially
parallel to the inner walls of the blower casing towards the outlet O. Owing to
the conformation of the blades, the air is drawn or forced through at the same
rapidity at the inner edges of the blades as at their outer edges. For all practical
purposes, there may be substituted for the hub k, a series of spokes to which the
blades would be attached. By arranging all the bearings of the shaft B outside
of the fan casing, they can be protected from dirt and dust, and thus any
interference with or cutting of such bearings by solid substances, which might be
drawn into the fan casing, is avoided; and by making the edges of the blades
straight and adjusting them close to the annular walls of the fan casing and the
partitiou H, the singing noise commonly produced by fans of ordinary construction
is obviated. The partition H is. supported in its position within the fan casing by
the arms J, J, connected with the interior of the casing, as shewn.
It will be noticed that the fan casing E, the fan wheel, and the partition H are
symmetrically constructed, the inlet I, outlet O, fan wheel, and the partition being
arranged concentric with the axis of the main driving shaft B, and the interior of
the front portion of the fan casing being made funnel shaped and curving
gradually towards the outlet O of the casing.
In the modification shewn in Figs. 4 and 5, one of the standards a is provided
with curved arms b to which is bolted the casing of the fan wheel, said casing
being, in this instance, made in two parts E and F connected together by any
suitable means, such as screw bolts passed through lugs. The fan wheel revolves
between the front F of the casing and the disc H, which latter is secured by
arms J to the inner surface of the part E of such casing.

page_text: In the operation of the apparatus the air is drawn into the casing at the front
at I, and is thrown off towards the outlet O by all the blades simultaneously
throughout the wheel, without any impediment to its movement, and is discharged
at the outlet O. The solid disc or partition H at the rear of the wheel within the
casing prevents the air thrown off from the blades of such wheel from flowing or
being drawn backward against the wheel, thus enabling the wheel to continuously
draw in a fresh supply of air and ensuring the movement of the entire body of air
so drawn in towards the outlet O and its free discharge therefrom. A serious
difficulty with the fans and blowers heretofore constructed having either the inlet,
or the outlet, eccentric to the fan wheel, has been that the air during the revolutions
of such wheel would have to be carried around by and in front of the wheel blades
for a considerable distance, thereby retarding the movement of the wheel, causing
back pressure on its blades, and consuming an excess of power. In this construction,
it will be seen, the movement of the air is largely parallel with the wheel blades
and symmetrical at all times with reference to all parts of the fan or blower, and
besides, the disc or centre plate H prevents the backward motión of the air from
the outlet of the blower case towards its inlet. This is an important advantage in
this construction. Owing to the ready and gradual passage of the air through the
apparatus, and the symmetrical construction and operation of the latter, the
working of the apparatus is practically noiseless.
Having now particularly described and ascertained the nature of the inven
tion and in what manner the same may be performed, I declare that what I
claim is:
1. In an exhaust fan or blower, the combination with the casing and a fan
wheel mounted within said casing, of a partition interposed between the outlet of
the casing and the inner central part of the fan wheel, the blades of said fan wheel
being adjusted to revolve between the inner surface of the casing and the partition,
substantially as described.
2. In an exhaust fan or blower, the combination with the casing and a fan
wheel mounted within said casing, of a cup-shaped partition interposed between
the outlet of said casing and the inner central part of the fan wheel, the blades of
said fan wheel being adjusted to revolve along the outer periphery and close to
the outer surface of said cup-shaped partition and close to and along the surrounding
surface of said casing, substantially as described.
3. The improvements in exhaust fans or blowers, substantially as hereinbefore
described and shewn with reference to the annexed drawings.
1007
ERNEST DE PASS,
Chartered Patent Agent,
78, Fleet Street, London, and 5^ Market Street, Nottingham,
Agent for the Applicant.