IMPROVE- MENTS IN FANS FOR BLOWING, WHICH IMPROVEMENTS ARE ALSO APPLICABLE TO FANS FOR EXHAUSTING, AND TO CENTRIFUGAL PUMPS
Year: 1876

page_text: LETTERS PATENT to William Henry Dugard, of Birmingham, in the County
of Warwick, Rolled Metal Manufacturer, for the Invention of " IMPROVE-
MENTS IN FANS FOR BLOWING, WHICH IMPROVEMENTS ARE ALSO APPLICABLE
TO FANS FOR EXHAUSTING, AND TO CENTRIFUGAL PUMPS."
aled the 5th June 1877, and dated the 20th December 1876.
PROVISIONAL SPECIFICATION left by the said William Henry Dugard at
the Office of the Commissioners of Patents on the 20th December 1876.
WILLIAM HENRY DUGARD, of Birmingham, in the County of Warwick, Rolled
Metal Manufacturer. 'IMPROVEMENTS IN FANS FOR BLOWING, WHICH IMPROVE-
MENTS ARE ALSO APPLICABLE TO FANS FOR EXHAUSTING, AND TO CENTRIFUGAL
PUMPS."
My Invention consists in constructing and arranging the parts of the said fans
and centrifugal pumps in the manner hercin-after described.
I will describe my Invention as applied to a fan for blowing-I construct the
rotating portion of the fan of two rings or discs with central openings. Those discs
are fixed on the fan shaft and concentric therewith by means of arms fixed to the
said discs at one end, and to the fan shaft at the other, so as to admit of the air
entering freely through the central opening in each disc and between the said discs
to their peripheries. These dises are parallel to each other and at right angles to
the shaft, and at a distance from each other corresponding to the desired width of
the fan. Between the two discs passages are formed for conducting the air from the
centre to the periphery. These passages are not radial but are curved in the follow-
ing manner: Starting from the central part of the disc the passage makes a curve
concave to the axis, the said curve proceeding from the centre to the periphery in a
direction contrary to that in which the discs rotate. This curve of the passage
changes about midway in its course, passing into a curve convex to the axis and
terminating in a direction radial to the axis of rotation. The passages have a
gradually diminishing sectional area from the central opening to the periphery. The
space between the passages is filled in or closed, the marginal surface of the filling
parts being parallel to the inner surface of the excentric case of the fan. The fan
rotates in a case the sides of which are as close as possible to the sides of the
[Price 6d1

page_text: revolving portion of the fan consistent with allowing it to rotate without touching.
Openings are formed in the sides of the case corresponding to the central openings
in the rotating parts. The circumference of the case has the figure of an evolute
curve, the distance from the inner surface of the case to the peripheries of the fan
discs increasing in proportion to the number of the openings in the rotating portion
which are discharging air at any given part of the circumference.
The sectional area at the discharge opening from the case equals the sectional
arca of all the passages at the circumference of the rotating part of the fan.
The application of my Invention to fans for exhausting and to centrifugal pumps
differs in no essential respect from its application to fans for blowing.
SPECIFICATION in pursuance of the conditions of the Letters Patent filed by
the said William Henry Dugard in the Great Seal Patent Office on the
14th June 1877.
WILLIAM HENRY Dugard, of Birmingham, in the County of Warwick, Rolled
Metal Manufacturer. "IMPROVEMENTS IN FANS FOR BLOWING, WHICH IMPROVE-
MENTS ARE ALSO APPLICABLE TO FANS FOR EXHAUSTING, AND TO CENTRIFUGAL
PUMPS."
My Invention consists in constructing and arranging the parts of the said fans
and centrifugal pumps in the manner herein-after described.
I will describe my Invention as applied to a fan for blowing-I construct the
rotating portion of the fan of two flat rings or discs with central openings. These
flat rings or discs are fixed on the fan shaft and concentric therewith by means of
arms fixed to the said rings at one end, and to the fan shaft at the other, so as to
admit of the air entering freely through the central opening in each ring and between
the said rings to their peripheries. These rings are parallel to each other and at
right angles to the shaft, and at a distance from each other corresponding to the
desired width of the fan. Between the two rings passages are formed for conduct-
ing the air from the centre to the periphery. These passages are not radial, but are
curved in the following manner -Starting from the central part of the ring the
passage makes a curve concave to the axis, the said curve proceeding from the
centre to the periphery in a direction contrary to that in which the rings rotate.
This curve of the passage changes about midway in its course, passing into a curve
convex to the axis and terminating in a direction radial to the axis of rotation.
The passages have a gradually diminishing sectional area from the central opening
to the periphery. The space between the passages is filled in or closed, the marginal
surface of the filling parts being parallel to the inner surface of the excentric case
of the fun. The fan rotates in a case the sides of which are as close as possible to
the sides of the revolving portion of the fan consistent with allowing it to rotate
without touching. Openings are formed in the sides of the case corresponding to
the central openings in the rotating parts. The circumference of the case has the
figure of an evolute curve, the distance from the inner surface of the case to the
peripheries of the fan rings increasing in proportion to the number of the openings
in the rotating portion which are discharging air at any given part of the circum-
ference.
The sectional arca at the discharge opening from the case equals the sectional
area of all the passages at the circumference of the rotating part of the fan.
The application of my Invention to fans for exhausting and to centrifugal pumps
differs in no essential respect from its application to fans for blowing.
•
Having explained the nature of my Invention, I will proceed to describe with
reference to the accompanying Drawing the manner in which the same may be
performed.
Figures 1 and 2 represent sections taken at right angles to one another of a fan

page_text: for blowing, the parts of which are constructed and arranged according to my
Invention; Figure 3 is a side elevation of the fan with the fan case in section.
The
The same letters of reference indicate the same parts in Figures 1, 2, and 3.
a is the fan shaft driven in any convenient way, and b is the fan case.
rotating part of the fan is constructed of two flat rings or discs c, o, fixed to the boss
on the fan shaft by the radial arms d, d, which are rivetted to the said boss and rings
as represented. Each of the said rings or discs c, c, has a central opening at e inade
in it, and corresponding openings at fare made in the sides of the fan case b. By
means of the said openings f, e, in the centre of the case and fan, air enters freely and
passes between the said rings to their peripheries in the manner herein-after
described. By an examination of Figure 2 it will be seen that the rings c, c, of the
fan work as closely against the sides of the case bas is compatible with perfect
freedom of motion of the said fan rings. Between the fan rings c, c, passages 9, 9,
are formed for conducting the air from the centre of the rings to their peripheries.
The said air passages g, g, in the fan are constructed by arranging and fixing
between the rings c, c, a series of filling-up blocks or parts marked h, h. These
filling up blocks or parts are connected to the rings c, c, at the outer cylindrical
edges of the said blocks by means of angle bars i, i, rivetted to the said blocks and
to the said rings as best seen in Figure 2, and the inner or feather edges of the said
blocks are rivetted to the rings c, c, by angle pieces at h, as seen in Figure 1. Each
of the filling-up blocks or parts h has such a figure that when the said blocks are
arranged and fixed between the rings c, c, the spaces or passages g, g, left between
them have the following curved figure. Starting from the central part of the ring
each of the passages g makes a curve concave to the axis a, the said curve passing
from the centre towards the periphery in a direction contrary to that in which the
rings c, c, rotate; that is, the rings c, c, rotate in the direction indicated by the arrow
at, but the curve just described of the passage g passes in the contrary direction.
The curve of the inner side of the passage changes about midway in its course,
passing into a curve convex to the axis a, as seen in Figure 1.
It will also be seen by an examination of the said Figure 1 that the outer edges
of the filling-in blocks or parts are not arranged concentrically with the edges of
the rings c, c, but are inclined thereto at the angle represented, thereby forming at
the periphery of the fau tapering channels opening into the main air passages g. It
will also be seen that the air conducting passages g have a gradually diminishing
sectional area from the central opening to the periphery of the fan. The circum-
ference of the fan case b has the figure of a snail or evolute curve, the fan being
arranged excentrically in the case b so that the distance from the inner surface of
the case b to the peripheries of the rings c, c, increases in proportion to the number
of passages y in the rotating fan which are discharging air at any given part of the
circumference of the fan; b is the discharge opening from the fan case, the sectional
area of which opening equals the sectional area of all the passages g at the circum-
ference of the rotating part of the fan. The filling-in blocks may be made solid or
hollow.
The revolving portion of the fan or centrifugal pump may in small fans and
pumps be made of cast metal, the passages g, g, and the interior of the blocks h, h,
being cored out, but for fans and pumps of large size I prefer to make the revolving
portions, with the exception of the central boss, of wrought-iron plates rivetted
together.
I construct and arrange the parts of fans for exhausting and centrifugal pumps
substantially in the manner herein-before described and illustrated with respect to a
fan for blowing. In centrifugal pumps the central openings in the case are con-
nected with the suction pipe, and in fans for exhausting the said openings are con-
nected with the suction pipe or flue.
Blowing and exhausting fans and centrifugal pumps made according to my
Invention are more effective in action than ordinary fans and centrifugal pumps.
They are also economical in construction and are less liable to derangement, and con-
sequently are more lasting than ordinary fans and centrifugal pumps.

page_text: Having now described the nature of my Invention and the manner in which the
same is to be performed, I wish it to be understood that I claim as my Invention the
improvements in fans for blowing and exhausting, and in centrifugal pumps, herein-
before described and illustrated in the accompanying Drawing, that is to say, making
the rotating part of the said fans and pumps of two flat rings or perforated discs
fixed on the fan or pump shaft and working closely in the fan or pump case, between
which rings curved air passages of the kind and having the sectional area described
and represented are formed for conducting the air from the centre of the said rings
and case to the peripheries of the said rings, the several rotating parts of the fan or
pump being constructed and arranged substantially as described and illustrated;
also the combination with the rotating parts of the fan or pump of a case having
the figure of a snail or evolute curve, the said fan or pump being arranged
excentrically in the said case substantially as and for the purpose described and
illustrated.
In witness whereof, I, the said William Henry Dugard, have hereunto set my
hand and seal, this Eleventh day of June, in the year of our Lord One
thousand eight hundred and seventy-seven.
Witness,
RICHARD SKERRETT.
Clerk to George Shaw,
Birmingham.
WILLIAM HENRY DUGARD. (L.S.)