Title of Invention

ROTOR WHEEL FOR A FRANCIS TURBINE

Abstract Rotor wheel (1) of the Francis turbine comprising a plurality of moving blades (2), each moving blade having an entry edge (2.1) and an exit edge (2.2) which are bent in plan view and/or side view, the bonding of the moving blades having at least one turning point W1, W2, W3; a rotor wheel rim (1.2) and a rotor wheel base (1.1), the moving blades (2) being located between the rotor wheel rim and the rotor wheel base, characterized in that connecting point A of entry edge (2.1) with rotor wheel rim (1.2) lies either on the same vertical line or behind connecting point C of the entry edge (2.1) with rotor wheel base (1) when viewed in direction of rotation (3.1).
Full Text The invention refers to the area of hydraulic machines in particular of
the water turbines of the Francis type of design. To such turbines
increasingly higher demands with regard to the efficiency and working
area are placed. It is desirable to have a variable input with regard to the
water flow volume from extremely partial load operation up to the over
load operation.
Also cavitation problems have continuously engaged the specialists.
Therein the blade geometry plays an important role. Numerous efforts
have been made through corresponding design of the flow path, in
particular of the blades, to reduce the cavitation danger. Only as an
example it is referred to WO 98/05863.
The assignment therefore lies at the base of the invention to design a
rotor wheel for Francis turbine of such type that a high efficiency is
achieved in all possible load ranges and that the cavitation danger is
reduced against known designs of rotor wheels.
According to this invention, the individual blades are designed in fully
definite way. The entry edges-seen in plan view -are bent. Therein it's
course shows a turning point so that two bent sections follow one on top
of the other. Besides the connection points of the entry edge at the rotor
wheel rim and rotor wheel base-seen in side view-are assigned to each
other in a wholly definite way. The connection point of the entry edge at
the rotor wheel base is located namely-seen in direction of rotation-at the
same position as the connection point of the entry edge at the rotor wheel
rim. It can also lie in front of it.
The invention is explained with the help of a drawing more closely.

Therein following is represented in details.
Figure 1 shows a Francis turbine in axial section
Figure 2 shows a section from the rotor wheel of the turbine as
per Figure 1 in magnified scale with line of vision
perpendicular to the axis of rotation of the turbine
(side view).
Figure 3 illustrates again in side view, however perspectively
represented, a second execution design of the
invention.
Figure 4 illustrates in a view analogous to that as per Figure 3
a third execution design of the invention.
Figure 5 shows in perspective representation in a plan view a
fourth execution design of a turbine blade as per
invention.
Figure 6 shows in a view analogous to that as per Figure 5 a
fifth execution design of a turbine blade as per
invention.
Figure 7 shows a rotor wheel as per invention for a Francis
turbine
The Francis turbine shown in Figure 1 is constructed as followingly.
A rotor wheel covers a multiple number of running blades. The rotor
wheel is rotatable around an axis of rotation 3. Rotor wheel 1 is
surrounded by a spiral casing 4.Besides a rim of guide blades 5 is
preconnected to the rotor wheel 1.
The turbine has a suction pipe 6. This covers an entry diffuser 6.1 with

a pipe bend 6.2 connecting to it and a suction box 6.3 again connecting
to it.
Figure 2 is a view perpendicular to the axis of rotation 3 on a moving
blade 2 and if fact on it's entry edge 2.1 -here represented thickened.
The moving blade 2 is located between the rotor wheel base 1.1 and rotor
wheel rim 1.2. It is connected in the area of the mentioned entry edge
2.1 to the rotor wheel base and to the rotor wheel rim that means
mechanically firmly linked, either through welding or as single piece
design. One considers the connection point A of the entry edge 2.1 to
the rotor wheel rim 1.2 and the connection point C of the entry edge 2.1
to the rotor wheel base 1.1. Both the points A and C lie in direction 3.1
of the circulation of the rotor wheel 1 at the same position. In case one
combines both the points A and C through a line with each other, then
this line runs parallel to the axis of rotation 3.
As per invention, connection point C could however also lie before con-
nection point B, consequently in the circulation in direction 3.1 could in
advance lead the connection point B.
Besides one recognizes that the entry edge is bent. In the present case
it shows two turning points.
The second execution design shown in Figure 3 is exactly similar to that
as per Figure 2. One recognizes again the rotor wheel base 1.1 the rotor
wheel rim 1.2 as well as a blade 2 located in between. The entry edge
2.1 shows a turning point. The exit edge 2.2 runs in contrast in straight
line.
One recognizes again the connection point A at which the blade 2 in the
area of it's entry edge 2.1 is connected to the rotor wheel rim 1.2 and
the connection point C at which it is connected to the rotor wheel base

1.1.
The line laid through both the points A and C - here represented in
broken line - runs parallel or nearly parallel to the axis of rotation 3.
The Figure 4 as per execution design, is equal to that as per Figure 3.
However the mentioned link line runs between the connection points A
and C inclined against axis of rotation 3. Both the execution designs are
represented in the Figured 5 and 6 in the plan view. The blade profile
1.1.1 of rotor wheel base 1.1 as well as the blade profile 1.2.1 of the
rotor wheel rim are likewise shown:
In both cases the entry edge 2.1 describes a curve with a turning point.
The curve is approximately S-shaped.
In the Figures 3 to 6 also the connection points of the exit edge 2.2 at
rotor wheel base and rotor wheel rim are represented. The blade 2 is
connected in the area of the exit edge 2.2 to the rotor wheel base 1.1
at point D and to the rotor wheel rim at point B.
The exit edge can have a straight line or bent course. It can be designed
similar or equal, as the entry edge 2.1
Also the one connection point B can -seen in circulation direction- leads
the other connection point D. However reverse is also possible that
consequently connection point D leads the connection point B.

Summary of reference numbers.
1. Rotor wheel
1.1 Rotor wheel base
1.1.1 Profile of rotor wheel base
1.2 Rotor wheel rim
1.2.1 Profile of rotor wheel rim
2. Moving blade
2.1 Entry edge
2.2 Exit edge
3. Axis of rotation
3.1 Direction of circulation
4. Spiral casing
5. Guide blades
6. Suction pipe

6.1 Entry diffuser
6.2 Bend
6.3 Suction box
W1, W2, W3 Turning points
A connection points of the blade in the entry edge area to the
rotor wheel rim.
B Connection point of the exit edge to the rotor wheel rim.
C Connection point of the entry edge to the rotor wheel base.
D Connection point of the exit edge to the rotor wheel base.

-6-
WE CLAIM:
1. Rotor wheel (1) of the Francis turbine comprising
-a plurality of moving blades (2), each moving blade having an entry
edge (2.1) and an exit edge (2.2) which are bent in plan view and/or
side view, the bonding of the moving blades having at least one turning
point W1,W2,W3;
-a rotor wheel rim (1.2) and a rotor wheel base (1.1), the moving
blades (2) being located between the rotor wheel rim and the rotor
wheel base,
characterized in that connecting point A of entry edge (2.1) with rotor
wheel rim (1.2) lies either on the same vertical line or behind
connecting point C of the entry edge (2.1) with rotor wheel base (1.1)
when viewed in direction of rotation (3.1).
2. Rotor wheel as claimed in claim 1, wherein connection point B of the
exit edge (2.2) with rotor wheel rim (1.2) lies on the same vertical line
or in front of or behind connection point D of the exit edge (2.2) with
rotor wheel base (1.1) when viewed in direction of rotation (3.1).
Dated this 4th DAY OF JUNE, 2004.

Rotor wheel (1) of the Francis turbine comprising a plurality of moving blades
(2), each moving blade having an entry edge (2.1) and an exit edge (2.2) which
are bent in plan view and/or side view, the bonding of the moving blades having
at least one turning point W1, W2, W3; a rotor wheel rim (1.2) and a rotor wheel
base (1.1), the moving blades (2) being located between the rotor wheel rim and
the rotor wheel base, characterized in that connecting point A of entry edge
(2.1) with rotor wheel rim (1.2) lies either on the same vertical line or behind
connecting point C of the entry edge (2.1) with rotor wheel base (1) when
viewed in direction of rotation (3.1).

Documents:

299-KOL-2004-FORM 27.pdf

299-kol-2004-granted-abstract.pdf

299-kol-2004-granted-claims.pdf

299-kol-2004-granted-correspondence.pdf

299-kol-2004-granted-description (complete).pdf

299-kol-2004-granted-drawings.pdf

299-kol-2004-granted-examination report.pdf

299-kol-2004-granted-form 1.pdf

299-kol-2004-granted-form 18.pdf

299-kol-2004-granted-form 2.pdf

299-kol-2004-granted-form 26.pdf

299-kol-2004-granted-form 3.pdf

299-kol-2004-granted-form 5.pdf

299-kol-2004-granted-priority document.pdf

299-kol-2004-granted-reply to examination report.pdf

299-kol-2004-granted-specification.pdf

299-kol-2004-granted-translated copy of priority document.pdf


Patent Number 228781
Indian Patent Application Number 299/KOL/2004
PG Journal Number 07/2009
Publication Date 13-Feb-2009
Grant Date 10-Feb-2009
Date of Filing 04-Jun-2004
Name of Patentee VOITH SIEMENS HYDRO POWER GENERATION GMBH & CO. KG.
Applicant Address ALEXANDERSTRASSE 11, 89522 HEIDENHEIM
Inventors:
# Inventor's Name Inventor's Address
1 KACHELE THOMAS SACHSENWEG 8, 89522 HEIDENHEIM
PCT International Classification Number F03B 3/12
PCT International Application Number N/A
PCT International Filing date
PCT Conventions:
# PCT Application Number Date of Convention Priority Country
1 10325698.9 2003-06-06 Germany