Improvements in Centrifugal Blowers.
Year: 1894

page_text: Date of Application, 31st July, 1894-Accepted, 1st Sept., 1894
Improvements in Centrifugal Blowers.
I, WILLIAM HENRY HARRISON, of 763 Broad Street, Newark, in the County
of Essex and State of New Jersey, United States of America Expert Accountant
do hereby declare the nature of my 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 the invention is to provide a new and improved centrifugal
blower, which is simple and durable in construction, very effective in operation,
and arranged to form a proper outlet for the air from the fan wheel, to prevent
undesirable compression of air in the wheel and consequent friction and loss of
power.
The invention consists of a fan wheel having series of radial main vanes forming
a passage for the air from the central opening of the wheel to the periphery thereof,
and a set of auxiliary vanes for each main vane and arranged parallel thereto and
extending from the periphery of the wheel to within a short distance of the next
following main vane.
The invention also consists of certain parts and details, and combinations of the
same, as will be hereinafter described and then pointed out in the claims.
Reference is to be had to the accompanying drawings forming a part of this
Specification, in which similar letters of reference indicate corresponding parts in
all the figures.
Figure 1 is a sectional side elevation of the improvement on the line 1-1 of
Figure 2;
Figure 2 is a cross section of the same on the line 2-2 of Figure 1;
Figure 3 is a perspective view of the fan wheel with parts broken out; and
Figure 4 is a sectional perspective view of the same.
The improved blower is provided with a blower casing A, preferably made in the
shape of two conical disks united with each other at their bases, the apexes of the
said disks being formed with air inlet openings A', as plainly shown in Figure 2.
The casing A is supported on a suitably-constructed frame B, and through the
openings A extends centrally the shaft C, journalled in suitable bearings attached
to or forming part of the frame A.
Within the casing A is arranged a fan wheel D having its ends made in the
shape of conical disks D' and D2, corresponding to the shape of the disks of
the casing A, so as to lie close to the interior surface of the said casing, as will
be readily understood by reference to Figure 2. The apexes of the disks D¹
and D are formed with openings corresponding to the openings A' of the casing A,
and the said disks are attached near their apexes to spiders D³ and D' respectively,
secured on the main driving-shaft C, so that the air can freely enter through the
registering openings in the casing A, and the disks D' and D2, to pass to the interior
of the fan wheel D. The latter is provided between the disks D' and D2 with a
series of main vanes E connecting the disks with each other and extending from the
openings in the apexes of the disks to their periphery, as will be readily understood
by reference to Figure 1. Two succeeding main vanes E form a passage for the air
from the central opening of the wheel to the periphery thereof, it being understood
that the bases of the disks D' and D' are located a suitable distance apart, as shown
in Figure 2.
In each of the air passages thus formed between the two succeeding vanes E, are
arranged a number of auxiliary vanes E', extending parallel to one of the said vanes
and extending from one disk D' to the other disk D, the said vanes extending from

page_text: the periphery of the fan wheel to within a short distance of the next main vane, so
as to leave an air passage between this vane and the ends of the auxiliary vanes E
in each of the air passages above referred to.
The current or blast created by the rotation of the fan wheel D is discharged from
the blower casing A at the perimeter of the casing, and for this purpose a tubular
neck or mouth A is formed on the said casing A, set substantially tangential to the
said casing, as will be readily understood by reference to Figure 1.
Now, it will be seen that when the main shaft C is rotated, air is drawn to
the fan wheel D through the openings A¹ in the casing A, and the openings in
the disks D and D2, to pass into the air passages formed between the radial vanes E,
it being understood that the air in its outward movement in each of the said
passages, passes into the air spaces formed between two succeeding individual
auxiliary vanes E', to finally discharge the air into the casing A and through the neck
or mouth A².
By reference to Figure 1, it will be seen that the auxiliary vanes E' on account
of being arranged parallel to one of the main vanes in the corresponding air passage,
decrease in size both in length and width, so that their inner ends increase in distance
from the centre of the wheel, whereby the area of each of the auxiliary vanes is
successively decreased, it being understood that the decrease of the vanes commences
from the auxiliary vane next to its parallel main vane, so that finally the smallest
auxiliary vane is the one nearest the periphery of the fan wheel and next to the
succeeding main vane E.
It will be seen that by this arrangement, the air passing up the space between the
ends of the auxiliary vanes E' and the next main vane E, can readily pass into the
passages formed by the parallel auxiliary vanes, to readily discharge the air at
the periphery of the fan wheel, so that no undesirable compression of air in the
wheel can take place, and a consequent reduction of friction follows, so that there
is no loss of the power applied.
Having now particularly described and ascertained the nature of my said
invention, and in what manner the same is to be performed, I declare that what
I claim is,-
1. In a centrifugal blower, a fan wheel having a series of plane radially diverging
main vanes, forming passages for the air from the center of the wheel to the
periphery thereof, and a set of auxiliary vanes for each main vane and arranged
parallel thereto, and extending from the periphery of the wheel to within a short
distance of the next following main vane, so as to produce a radial passage along
the said main vane, and a series of parallel passages branching off from the said
radial passage, substantially as described.
2. In a centrifugal blower, a fan wheel consisting of two frusto-conical end pieces
placed with their bases adjacent and parallel to each other, and with their contracted
ends facing in opposite directions, trapezoidal main vanes secured between the said
end pieces, and auxiliary vanes extending between the end pieces from the bases
thereof to within a distance from the tapered ends of the end pieces, the said auxiliary
vanes being arranged in step-like fashion between each two main vanes, substantially
as described.
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CT 1 1001
A. M. & WM. CLARK,
53, Chancery Lane, London, Chartered Patent Agents.