Improvements in Centrifugal Fans,
Year: 1898

page_text: Date of Application, 19th Oct., 1898-Accepted, 26th Nov., 1898
COMPLETE SPECIFICATION.
Improvements in Centrifugal Fans,
We, HAMMERSLEY HEENAN, Engineer, 4, Chapel Walks, Manchester, and
WILLIAM GILBERT, Engineer, 47, Victoria Street, Westminster, 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:-
This invention relates to improvements in the construction of fans used for
ventilating mines, increasing the draught in boiler flues and other purposes and
has for its object the provision of means whereby the fan proper is constructed
more rigidly than is usually the case, and also, in fans of large dimensions, to
dispense with the intermediate bearing which is often employed to prevent the
shaft bending under the weight of the fan proper.
In carrying out our invention we provide the tips of the vanes of the fan with
an angular stiffening plate rivetted or bolted to the back of the vane, and
arranged so that a portion of this plate forms a right angle or nearly so with the
Thus, the angular shape of the stiffening plate would prevent the ends of
the vanes from bending back under the influence of centrifugal force, and other
causes, when the fan is running at a high speed.
vane.
In order to facilitate the smooth passage of the air through the fan we continue
these stiffening plates in a curve until they again reach the vane at a point
nearer the axis of the fan. At this point the plate is fixed to the vane.
The vanes in large fans are preferably made in several pieces, the usual number
in the type known as double inlet" being four.
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Between each two pieces is arranged a ring or disc to which the edges of the
vanes are secured by means of suitable angle irons. The central disc is firmly
attached to the shaft, by rivetting or bolting, and also by means of the coned plates
which also prevent the disc buckling. The two outside rings are each preferably
arranged at a distance of about two thirds of the half width of the fan from the
central disc, and on either side of the latter, and, in order to drive these rings
from the shaft without putting undue strain on the central disc and the inner
portions of the vanes, we provide two pairs of stay rods, one pair on either side
of the central disc. These stay rods are tangential to the shaft, and are rivetted
or bolted thereto at the middle, the ends being secured to the side rings.
Thus the driving is effected in an efficient and equal manner, and all un-
necessary straining of the various parts is avoided.
In order that the invention may be more clearly understood, reference is had
to the accompanying sheets of drawings in which Fig. 1, is a view of the fan
proper showing the edges of the vanes. Fig. 2 is a section in a plane at right
angles to Fig. 1. Fig. 3 is a cross section of a fan in position, and Figs. 4
and 5 are details of the tips of the vanes.
As shown in the drawings each vane A is constructed in four parts, a, a, and b, b.
The four pieces are arranged in line but are separated by the central disc C
and the two side rings D. At the tip of the vane is fitted the plate E shown in
detail in Fig. 4, which is formed with the angle e to stiffen the outer edge of the

page_text: vane. The curved part e¹ of the stiffening plate serves to direct the gases or air
as they pass through when the fan is running.
In the modification shown in Fig. 5, the stiffening device consists of a Ziron e
one flange of which is rivetted to the vane and the other to a somewhat differently
shaped curved plate which is notched to pass over the dise C and rings D.
This curved plate serves the same purpose as the one shown in Fig. 4, but is
perhaps more efficient owing to the curvature corresponding to shape of the vane,
or nearly so.
The stiffening plates also ensure the four portions forming the vane being in
line, and the gusset plates F, serve to tie the outer portion of the vanes to the
central disc, and side rings.
The side rings 1) are rigidly connected to the shaft G, by means of the stays H,
which are preferably round iron rods flattened at the middle h, and rivetted or
otherwise secured to the shaft, and also flattened at the ends in a plane at right
angles to the middle part and attached to the side rings in a similar manner.
Our improved shaft G is built up using metal tubes of considerable diameter,
thereby ensuring great strength and rigidity, with comparative lightness of
construction.
The shaft may be constructed in sections of convenient length and the connection
between adjacent sections may be made by a flanged joint, or a circular cover
plate, or the ends may be arranged to overlap (as shown in the drawings) and
well secured together by bolting or rivetting.
Suitable journals J and J (working in bearings preferably of a swivel type)
are secured at each end of the shaft, the construction of the shaft permitting any
intermediate bearing to be dispensed with.
Having now particularly described and ascertained the nature of our inven-1
tion and in what manner the same is to be performed, we declare that what
we claim is:
CLAIMS.
1. In a centrifugal fan the strengthening of the tips of the vanes by means of
angular plates, each provided with a curved sloping portion substantially as
described and shown.
2. In a centrifugal fan constructing the shaft from tubes substantially as
described for the purposes specified.
3. In a centrifugal fan the combination with the tubular shaft and the tangential
stays constructed substantially as described and for the purposes specified
4. In an improved centrifugal fan the combination with the strengthening
plates on the vanes, the tangential stays and the tubular shaft constructed and
operating substantially as described, and shown in the drawings, and for the
purposes specified.
Dated the 13th day of October 1898.
HAMMERSLEY HEENAN,
WILLIAM GILBERT,
Applicants.