Note: Descriptions are shown in the official language in which they were submitted.
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"Fluid Contacting Surfaces and Devices Incorporating Such Surfaces'
This invention relates to fluid-contacting surfaces
and devices incorporating such surfaces, and more particularly
relates to fluid-contacting surfaces and devices which are
arranged to affect, modify or control the flow of fluids, as
for example the fluid-contacting surfaces of stationary deflectors
or rotatable devices such as turbines, impellers or propellers
and the like which may be used ~or a variety of purposes and
applications e.g. as in pneumatic and hydraulic applications.
Conventional design of the fluid-contacting surfaces
of such as impellers, propellers and like devices can be quite
complex and involve relatively high design and production
costs for such devices. It is accordingly an object of the
- present invention to provide an alternative me~ns for generating
or forming a fluid-contacting surface, and a device incorporating
at least one such surface, in a relatively simple but effective
and effiaient manner.
Another object of this invention is to provide a fluid-
conl:acting surface and/or device incorporating at least one
such surface, which may have special purpose applications
and provide more effective fluid flow control than at least many
conventionally formed fluid-contacting surfaces and devices.
Other and more particular objects and advantages of the
present invention will become apparent from the ensuing
description.
According to one aspect of this invention therefor,
a fluid-contacting surface comprises at least a part of that
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surface generated by a generating line extending radially
from a point of origin on an axis and rotated about said
axis from a said point of origin and radially position so
asto sweep through a decreasing angle relative to the axis
as rotation takes place.
In another aspect of the invention, there is provided a
- stationary fluid deflector incorporating the fluid-contacting
surface generated according to the preceding claim.
In a further aspect of the invention, there is provided
an axial flow fluid impeller or propeller incorporating at
least one fluid-contacting surface generated as aforesaid.
The invention further includes the methods of forming
the said generating surface and the said stationary deflector
and/or axial flow fluid impeller or propeller.
Some preferred aspects of the invention will now be
described by way of example and with reference to the accompanying
drawings, i.n which: .
FIGURE 1 is a diagram illustrating the principles
involved in generating a fluid-contacting surface in accordance
with the invention
FIGURE 2: is an axial or end view of a first form of
an impeller or propeller blade Eormed in accordance with the
invention
FIGURE 3: is a view in the direction of arrows III-III
of figure 2
FIGURE 4~: is a view in the direction of arrows IV-IV
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of figure 2
FIGURE lj: is an axial view of ablade part for forming
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the impeller or propeller of fiqures 2, 3 and 4, illustrated
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in a flat form prior to shaping
FIGURE 6: is a perspective view of another form of the impeller
or propeller form in accordance with the invention
FIGURE 7: is a side view in the direction of arrow VII of flgure 6
FIGURE 8: is ~ side view in the direction of arrow VIII of figure
FIGURE 9: is an axial or end view of the arrangement of figure 6
as viewed in the direction of arrow IX
FIGURE 10: is an axial view of one blade part for forming the impell-
er or propeller of figures 6 to 9 inclusive, lllustrated in the flat form
prior to shapins
FIGURE 11: is a side view of a further impeller or propeller similar
to but excluding a modification of the impeller of figures 6 through to
9, and
]FIGURE 12: is a view in the direction of arrows XII-XII of figure 11.
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~ Referring firstly to figure 1 of the drawings, this diagrammatically
illustrates how a fluid-contacting surface in accordance with the present
invention may be generated about a polnt or origin O of an axis of
rotation Z. A generatrix point P defines a radius vector OP, transverse
axis X extends at right angles to the axis of rotation Z and the angle
is formed between the X axis and the projection OQ of the radius vector
OP onto the XY plane, with the a~gle 0 being formed between the radius
vector OP and the ~axis. The parametric equations defining the curve
generated by the point P are where R" represents the magnitude or length
of the radius vector OP:
X = R". sin ~ cos~'
Y = R" sin 9 sin~, and
Z = R" cos ~
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Either of the angles ~ and ~ may be eliminated from the equations by ex-
pressing it as a function of the other.
As seen, in the XY~ co-ordinatesystem the point of origin O is at
the intersection or point of origin of the three co-ordinateaxes, and with
the angle between the true axis of rotation ~and radius vector OP
referred to as ~, the fluid-contacting surfaces generated in accordance
with this invention is defined as the locus of the generatrix line OP
where ~ = f(~) i.e. is some function of the angle ~5 .
For example, where
~ 3
or any other function, including tables of discrete values.
Simply put, the fluid-contacting surface in accordance with this
invention, is any part of that surface generated by the radius vector or
generating line OP rotated about the axis 2} frc~ the point of origin and
s~rept between the transverse axis X through a decreasing angle to lie ad-
jacent ancl parallel the axis ~k The surface may include the full 90
sweep between the transverse axis X and the true axis of rotation ~} or
a part thereof, or the full 180 sweep from adjacent the axis Z to one
side of the point of origin O through the transverse axis X to lie adjac-
ent the axis ~at the opposite side of the point of origin O; and the sur-
face thus formed may be duplicated or otherwise mNltiplied in providing
a plurality of similar fluid-contacting surfaces in continuous or spaced
relationship about the axis of rotation ~e.g. as in providing
fluid-contacting surfaces on a twin or mult:i bladed impeller or propeller.
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The angle through which the radius vector or generating
line OP is swept and the angle of rotation about the axis
~ may be unrelated or each may be a function of the other
such as, for example, directly proportional, according to
the use to which the fluid-contacting surface is to be put.
Similarly ~he va:riance in the angle through which the
generating line OP is swept may be unrelated or directly
proportional to the speed of rotation of the line OP about
the axis ~.
Further, it is envisaged that the generating line OP
can remain of constant length throughout its rotational
and angular sweep relative to the axis ~., so that the said
surface, and any impeller or propeller blade formed thereby or
incorporating such surface, may be swept through an imaginary
sphere or spheroidal form,or the length of the generating
line OP can be varied as it is swept through its prescribed
angle and rotated about the axis ~ from its point of origin O
in forming a fluid-contacting surface or device incorporating
such ~urface arranged to sweep through an alternative required
orm as hereinafter described.
Referring now to figures 2, 3 and 4, the rotatable impeller
or propeller may be constructed with a blade 1 formed from such
as a thin shee.t of metal or other suitable material in initially
flat circular disc form of radius equal to the length of the
generating line OP and providedwith either a single radial slit S
or a small sector R,R' cut out, as iliustrated by way of example
in figure 5 of the drawings; and the whole or part disc form
may then be twi,sted and bent into shape with the radial slit
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(or sector) edges R, R' disposed in opposition 180 apart
to lie on or adjacent the axis of rotation ~ of the impeller
or propeller.
In constructing the impeller or propeller in this manner,
the slit S between the radial edges R, R' of the blade 1 may
be a width such that is is substantially equal to the diameter
of an axial shaft 2 for the impeller or propelIer and to which
the said radial edges R,R' can be secured such as by welding.
Convehtional screw type impellers or propellers are
formed with at least the inner parts of their fluid-contacting
surfaces as al true helix or substantially a true helix about
the axis of rotation, with such helix being maintained
perpendicular to the axis as it progresses longitudinally
thereof; and many propellers are provided with a further helical
twist along their radial axes towards their outer periphery.
It will be seen that in the present invention there is a
subst~mtial difference in construction in that the blade
is simply spirally formed from one point of origin O on the axis
of rot:ation ~ so that from the one medial position on the
transverse axis X where the fluid-contacting surface generating
line OP is disposed perpendicular to the axis of rotation ~,
either side of such perpendicular position the angle of
inclination ~ relative to the axis ~ progressively decreases
as it approaches the axis of rotation ~ until it is positioned
parallel and adjacent thereto i.e. adjacent the longitudinal
surface of the axially disposed shaft 2.
In this ~orm of the invention, a pitch value of n = 2 has
been selected, with the result th,at the blade 1 curves tightly
into the main axis of rotation ~ of the impeller or propeller. In
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figure 2, radial lines 3 represent equal increments of the
angle ~ of figure 1 and the dashed lines 4 join sample points
of equal displacement from the plane of the X and Y axes.
In this arrangement, with rotation of the impeller
and shaft about axis ~ a positive axial thrust on the fluid is
exerted by the fluid-contacting surface of the blade 1 for
efficient and effective operation either in moving the fluid
coaxially or moving such as an aeroplane or boat relative
to the respective fluid ~air or water) in which it is located.
The arrangement shown in figures 2,3 and 4 illustrate
a single blade, but a complementary second blade can be provided
and mounted in complementary diametric opposition, as shown in
broken outline; and it will be seen also that on rotation the
blade 1 or blades 1 will sweep through an imaginary sphere A
as indicated in broken outline in igure 4.
Ref0rring now to figures 6 to 10 of the accompanying
drawings, a twin bladed impeller or propeller is provided with a
dife!rent pitch and conse~uential diferent shape formed as a
result of each blade 1' being constructed from thin sheet metal
initially of disc form as before but with a relatively large
segment S' cut out between radial edges R and R', as shown
in figure 10.
Again and with the ~two blades 1' and their common shaft
2' rotated about the said axis ~, the blades 1' will sweep through
an imaginary sphere A. It will be appreciated however that the
invention is nlDt confined to impellers or propellers in which
the fluid-contacting surface generating line OP is constant, but
by varying the length of such line (e.g. by a gradual increase
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to a peak followed by a gradual decrease) during formation
of the impeller, or by subsequent shaping of the impeller
blades once initially formed as before described, impellers
or propellers of different shapes and sweeping different
shaped volumes c:an be provided to meet the desired situations.
For example, the impeller blades 1' can be shaped so that on
rotation a substantially cylindrical volume may be swept as
indicated in chain dot outline B in figure 7, or the blades 1'
may be shaped so that an ellipsoidal form C is swept by the
impeller blades. In other variations the basic spheroidal form
may be in the main applicable to the medial part of the impeller
or propeller, but segments of the sphere or spheroidal form at the
opposite axial ends may be cut off, or the longitudinal axis
of the impeller or propeller substantially shortened relative
to the true diambter.
Referring now to figures 11 and 12 of the accompanying
drawings, a twin bladed impelIer or propeller may be provided
which is s~stantially similar to the impeller or propeller
previously described with reference to figures 6 to 10 of the
drawings, except that in this arrangement whilst the two blades
1'' are similarly formed from a thin flat disc arrangement, on
assembly or prior to assembly axial end portions are cut out
at T to more particularly separate the hlades 1'' at the shaft
2 " each side of the medial portion 1" a
- Experiments with impellers and impeller blades formed as
aforedescribed in accordance with this invention have shown that
in many instances and on rotation in one direction the formed
impellers will give a far more concentrated axial thrust than
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conventional impellers or similac overall size, similarly powered,
and rotated at the same revolution6. The invention thus has
particular applications in the construction of small and large air
circulation, cooling and ventilating fans and thè like: and it i8
further expected that the invention will have useful applications
in marine propulsion for boats and the like, and/oe the impelling
or pumping of vacious kind6 of fluids, and po6sibly further have
aeronautical applications.
It will be appreciated that varying degrees of efficiency and
effectiveness in operation of devices such as rotary impeller6 and
propellers, ol stationery~movable deflector6 and the like, in
accordance with the invention will result and be dependent on the
extent of rotational and arcuate 6weep of the generating line in
focming the fluid contacting surface concerned. Whilst in some
instances, particularly for stationery deflectors, surprisingly
effective fluid deflection is obtainable with minimal rotational
and/or arcuate sweep of the surface generating line: for most
practical applications the surface generating line will desirably
be required to move through at least twenty percent (20%.) of a
revolution about the axi6 and through a longitudinal arc of at
least 15 degrees.
As before indicated, the invention particularly lends itself
to simplification of manufacture utilizing sheet materials, but it
will b~ appreciated that the invention is not confined in this
respect: and that the impeller, propeller or other blades or
deflecl:ors incorporating the fluid-contacting ~urface or surfaces
in accordance with the invention can be manufactured and formed by
other means.
Particular forms of the invention and its applications have
been de6cribed only by way of example with reference to the
accompanying drawings, and it will be appreciated that other
variations of and modifications to, and applications of, the
invention may take place without departing from ~he scope of the
appended claims.
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