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Патент USA US2112300

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{March 29', 1938.
L. F. MOODY
2,112,300
EPICYCLIC FLUID FLOW APPARATUS
Filed Aug. 28, 1935
4 Sheets-Sheet 1
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O.
INVENTGR
arch 299 193.
L... F. MOODY
EPlCYCLIG FLUID FLOW APPARATUS
Filed Aug. 28? 1935
ENVENTOR
March 29, 1938,
2,112,300
L. F. MOODY
EPICYCLIC FLUID FLOW APPARATUS
4 Sheets-Sheet 3
Filed Aug. 28, 1935
aura v
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'
INVENTQR
arch 29, W38‘,
L, F. MOQDY
2,1123%
EPIGYCLIC FLUID FLOW APPARATUS
Filed Aug. 28, 1955
4
A Sheets-Sheet 4
Patented Mar. 29, 1938
2,112,300
UNITED srares
ATENT OFFIQE
2,112,300
EEECYCIJC FLUIDv FLOW APPARATUS
Lewis Ferry Moody, Princeton, N. J.
Application August '28, 1935, Serial No. 38,162
10 illaims. (Cl. 253-148)
This invention relates generally to ?uid pro~
pelling and ?uid power generating apparatus of hydraulic contour, and mounting the pivots in
the blade type and more particularly to improved bearings carried by the runner hub so that each
5
means for minimizing the possibility of friction
blade is free to rotate with respect to the hub and
between the blades and ?uid ?owing thereover,
the invention being particularly applicable to hy
shaft of the runner. When left free to rotate
relatively to the runner as a whole, each disk will
automatically endeavor to assume that speed of
relative rotation which will give a minimum fric
draulic turbines, pumps and propellers wherein
the hydraulic friction may be of appreciable mag
nitude.
10
‘
The history of hydraulic turbine and pump
practice shows a continued struggle to increase‘the
permissible speeds of rotation of the revolving ele
ment, to make them suited to the speeds attain
able in the electric generators of motors to which
15 they are usually coupled, and to reduce the weight
and cost of the machinery and surrounding
structure. Particularly in adapting the machines
to low heads and large water quantities the ques
tion of speed becomes of major importance, often
20 justifying a- considerable sacri?ce in efficiency to
attain a high speed. The propeller type turbine
and pump using high relative velocities between
the runner blades and the water have accom
plished a notable increase in rotational speed.
25
Employing these high relative velocities, how
tional drag from the working ?uid, thus minimiz
ing the resistance opposing rotation of the run
ner and at the same time minimizing the dis
turbance set up in the ?owing ?uid and loss 'of l0
head due to eddies.
The source of surface friction resistance is in
the boundary layer of ?uid in contact with and
close to a surface along which it ?ows. If the 15
surface can move with the ?uid this source of
loss and turbulence is eliminated. Moreover, the
drag or tangential friction force is closely propor
tional to the square of the relative velocity, so
that if the relative velocity is reduced to one
half its original value, the drag or frictional force 20
is reduced to only about one-quarter of its pre
vious amount. Consequently it is not necessary to
reduce the relative velocity to zero at all points;
but any material reduction in velocity will be re
?ected in a much greater proportional reduction
in friction and loss of energy. The complete run
ner or rotating element of this invention involves
an epicyclic action (sometimes termed a planetary
motion) ~a series of blades or disks which rotate
ever, necessitates a high surface resistance and
loss of head which not only impairs e?iciency,
but erTectually resists any effort toward further
speed increases; and the attempt to reduce this
30 resistance by employing narrow blades of reduced
area has been ineffective beyond a certain‘ point
and if carried too far results in cavitation,‘ pitting relatively to the revolving system at the same
time that the system itself revolves. Any point
and instability and loss of ei?ciency without ma
on a blade traces in space an absolute path which
tcrial increase in speed. I, therefore, have intro
35 duced a method of eliminating a large portion of is epicycloidal in character. It is, of course, nec
essary to modify the blade’s peripheral contour
this loss by a change in the whole method of ac
somewhat to make it circular, thus cutting away
tion between the blades and ?uid. This new prin
ciple is applicable to hydraulic turbines, pumps, its outer corners farther than is usually done in
reversible pump-turbines, air blowers, marine the case of turbinesv and pumps. This is partly
compensated by increasing somewhat the num
40 propellers or any machine utilizing the interac
tion of moving blades and ?owing ?uid; but is ber of blades-—say from four to six or eight, and 40
illustrated here as applied to speci?c machines allowing considerable overlap in the inner por
tions near the hub, which is not objectionable.
or elements, and particularly illustrated in a hy
draulic turbine.
45
,
According to the principle of this invention,
while the conformation of the blades remains
?xed with respect to the hub of the runner or re
volving element, the actual material and, there
fore, the surface of each blade moves backwardly
50 with respect to the motion of the hub and of the
runner as a whole, so that the relative velocity
between ?uid and blade surface is reduced.‘ This
is accomplished by forming the blades ‘as pivoted
circular disks properly cupped or curved in planes
55 containing the pivot axis to provide the proper
The blades are also inclined at a smaller angle,
relatively to a plane normal to the runner axis,
than is usual in turbines and pumps; that is, the
blades are given a smaller pitch than usual, in 45
speaking of a marine propeller. This is per
missible since a higher speed of runner rotation
is to be attained. The new type of runner here
described is particularly adapted to very high
50
speci?c speeds.
Certain portions of the boundary wall of the
?uid passages usually comprising portions of the
stationary elements of a. turbine or pump may
also when desired follow the principle here de
55
2,112,300
2
removable portions permitting the ready assem
scribed, that is, they may be made freely rotat
able to permit them to take up automatically a
motion minimizing the wall resistance of the
?owing medium. The same principle may also
be applied to the conical end or other portions of
the runner or propeller itself, this cone or por
tion being mounted. on a bearing coaxial with
the runner so that it is free to revolve at a speed
different from that of the runner proper.
The principle of the invention will be better
bly or removal of the blade disks.
In Fig. 1 (not shown in Fig. 4) is illustrated the
method of further reducing the resistance to flow
by making the inner wall l8 of the transition
space 4 movable. Although this provision is not
as important as the blade rotation, since the
absolute velocity of flow along this wall is much
less than the relative velocity of the runner
understood by referring to the following de
Wall friction opposing flow and the consequent
scriptions of illustrative embodiments, in which:
turbulence propagated in the flow. The portion
I8 is freely rotatable, supported by the bearings
Fig. l is a sectional elevation of an axial-flow
shown, either ball bearings as indicated or plain
hydraulic turbine runner and surrounding ele
ments;
section of the runner of Fig.
Fig. 2 is a partial
journal bearings.
with central core or cone registering with the
runner. This type is advantageous when unit
Fig. 3 is a section of one of the blades of the
runner of Fig. l in a plane containing the pivot
spacing permits its use, particularly with the
house containing the turbine of Figs. 1-3;
Fig. 5 is a sectional elevation of a diagonal
flow hydraulic turbine runner and surrounding
parts;
Fig. 6 is a sectional elevationrof a horizontal
shaft pump, turbine or reversible pump-turbine;
Fig. 7 is a sectional elevation of a vertical
shaft pump.
'
In the turbine of Figs. 1 to 4 the water enters
30 from the spiral casing I of usual form, passes
between the stay vanes 2, pivoted guide vanes
15
In Fig. 1 the draft tube is of the spreading type
l, on line 2-2 of Fig. 1;
of the blade;
.
20 axis
Fig. 4 is a sectional elevation of the power
25
blades, it may be used in addition to reduce the 10
large diameter hub here required. This hub di
ameter is of the same general proportions as in
many turbines of the Kaplan or adjustable blade
type, and the relatively large size has not been
found prohibitive.
25
In Fig. 4 the same turbine as in Fig. l is shown
in connection with an elbow draft tube. Here,
if desired, the lower conical end IQ of the runner
hub can be made freely rotatable, carried by a
journal bearing on a stub shaft mounted in the 30
bottom wall of the hub.
In Fig. 2, 12 indicates the absolute velocity of
the runner hub and rotating system; q indicates
or wicket gates 3, flows through the transition
space 4, runner 5 and into the draft tube 6. The
the backward relative velocity of the blade disk.
At any point, the effective relative surface velocity
head cover 1 supports the main shaft bearing 8,
35 stuffing box 9, and guide vane operating mecha
nism W. The main shaft H is coupled to, or
continued to form, the shaft I2 of the generator
[3, where it is supported by a thrust and guide
will be 11-11, 1) being the relative velocity of the 35
system or of a non-rotating blade with respect
to the water, or of the water with respect
blade. If at a point in the outer portion
blade q assumes a value of say 42.3% of
effective surface velocity will be 57.7% of
to the
of the
v, the
40
v and
bearing. At its lower end it is bolted to the hub the frictional drag will be only one-third of that
'40 M of the runner 5. This hub carries a series of
with a ?xed blade.
inclined bearings 15 in which are rotatably sup
In Fig. 6 my improved runner is applied to a
ported the pivots E6 of the blades or disks l1. horizontal shaft hydraulic apparatus adapted to
45
These blades have their outermost portions ex
function either as a pump, turbine or reversible
posed to the flowing fluid which drives the run
pump-turbine while in Fig. '7 the runner is ap
45 ner by acting on them. Their inner portions are plied to a vertical shaft pump. The foregoing
within the hollow hub III which is ?lled with idle construction may embody any of the features of
water. The blades or disks pass through slots the other modi?cations, but preferably the Fig.
formed to receive them without touching them, a 6 runner is the same as shown in Fig. 1, while the '
small clearance being provided. It will be un
Fig. 7 runner is the same as Fig. 4 and accord
50 derstood that in passing through the dead water
ingly carries the same reference numbers.
within the hub during their relative rotation the
In Fig. 6 the runner or impeller 5 operates
blades will suffer a certain amount of retarding within a space between two sets of guide vanes,
drag, but less than the forward drag from the 20, 2|. When operating as a pump, vanes 20
active flow outside, so that the blades will auto
are guide vanes directing the flow to the runner
55 matically assume a mean velocity minimizing the
and 2| are diffusion vanes decelerating the ?ow
total drag, or balancing the forward and back
therefrom. When operating as a turbine, the
ward forces. Furthermore, the active surface directions of flow and runner rotation are re
forces near the outermost limits of the runner,
where the blades encounter the highest relative
velocities, will exert a large moment to rotate
the vanes on account of the large effective lever
arm about the pivots, so that the ?nal velocity
of relative rotation will tend to accommodate it
self to the rapidly moving part of the flow. That
65 part of the ?ow near the hub surface will be com
paratively little effected by the blade rotation,
but here the relative velocities and resistances are
very much less than in the region of the blade
“tips” or outermost portions. The net result will
be a material reduction in the average relative
75
velocity between blades and ?owing water, and
a still greater proportional reduction in drag and
loss of head.
The bearings l5 for the pivots are shown with
versed.
.
In Fig. '7, the flow is upward between the guide
or stay vanes 22, through the impeller 5, and the
diffusion vanes 23.
From the foregoing disclosure, it is seen that
I have provided very effective means for mini
mizing frictional resistance between the more
vital portions of the apparatus such as the blades
or a portion of the wall forming the transition
space. It will of course be understood that vari
ous changes in details of construction and ar
rangement of parts may be made by those skilled
in the art without departing from the spirit of
the invention as set forth in the appended claims.
I claim:
1. Fluid apparatus comprising, in combination, 75
2,112,300
a rotor hub rotatable about a ?xed axis and hav
ing overlapping blades directly supported by said
hub, said blades normally rotating in only one
_ direction relative to the hub during rotation
thereof, and means forming a passage in which
said rotor operates.
2. Fluid apparatus comprising, in combination,
a rotor having a hub rotatable about a ?xed axis
and blades supported directly by said hub and
10 continuously movable in one direction relative
thereto during rotation thereof, and means form
ing a ?uid passage in which said rotor is co
axially disposed.
3. Fluid apparatus comprising, in combination,
a rotor hub rotatable about a ?xed axis and hav
ing disc blades supported directly by said hub
and individually rotatable relative thereto dur
ing rotation thereof, and means forming a ?uid
passage in which said rotor is coaxially disposed.
20
4. Fluid apparatus comprising, in combination,
a rotor having a hub rotatable about a ?xed axis
and disc blades supported directly by said hub,
means for supporting the blades for continuous
rotation relative to the hub, and means forming
a fluid passage in which said rotor is coaxially
disposed whereby said disc blades rotate during
?ow of ?uid thereover thereby to minimize sur
face friction between the blades and ?uid.
5. Fluid apparatus comprising, in combination,
a rotor having a hub rotatable about a ?xed axis
and disc blades supported directly by said hub
means for supporting said discs by said hub for
continuous uni-directional rotation! about in
clined axes, and means forming a ?uid passage
in which said rotor is coaxially disposed.
6. Fluid apparatus comprising, in combination,
a rotor having a hub rotatable about a ?xed axis
and blades supported directly by, said hub and
continuously revoluble relative thereto during
40 ?uid ?ow over said blades, the opposite sides of
3
said blades having different contours, and means
forming a ?uid passage in which said rotor is
coaxially disposed.
7. Fluid apparatus comprising, in combination,
a rotor having a circular hub with recesses there
in, disc blades having one portion disposed within 5
said recesses and another portion projecting out
wardly from the surface of said hub, and means
for supporting said blades for continuous uni
directional rotation.
10
‘8. Fluid apparatus comprising, in combination,
a rotor having a circular hub with recesses there
in, disc blades having one portion disposed within
said recesses and another portion projecting out
wardly from the surface of said hub, and means
for supporting said disc blades for continuous ro
tation in the same direction relative to said hub.
9. In a hydraulic turbine, in combination, a
rotatable hub, a series of relatively ?at circular
disks pivotally mounted in said hub and rotatable 20
relatively thereto about axes different from the
axis of rotation of said hub; said disks passing
through slots in the hub wall formed to provide
small clearance around said disks, and the axis
of said disks being inclined in a direction more
nearly perpendicular than parallel to a plane
normal to the axis of rotation of the hub.
10. In a rotary ?uid apparatus, in combination,
a rotatable hub, a series of relatively ?at circular
disks pivotally mounted in said hub and rotatable -
relatively thereto about axes different from the
axis of rotation of said hub; said disks passing
through slots in the hub wall formed to provide
small clearance around said disks, and the axis
of said disks being inclined in a direction at an
angle to the axis of hub rotation when projected
in a plane containing said hub axis, and also in
clined with respect to said plane.
LEWIS FERRY MOODY.
40
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