FIELD OF THE INVENTION:
The present invention relates to the field of an apparatus and an inspection method to identify a bend of a rotor disc in refurbishment turbines. Particularly, the present invention relates to an apparatus and an inspection method to identify bend of a rotor disc in cases of space constraints between the rotor discs.
BACKGROUND OF THE INVENTION:
Generally, Steam Turbines will come for refurbishment in two cases: 1) After operating for few years may not be able to generate power as per the design condition. 2) Failure during operation. Refurbishment of a turbine includes replacement of damaged blades, removal of the bend of the rotor discs and the rotor, balancing of the rotor etc., The rotor includes integrally formed or attached plurality of rotor discs spaced apart along the axis of the rotor. The distance between the rotor discs is a design requirement to achieve meridional flow path of the steam. To fulfill the design requirement, in some cases, the distance between the rotor discs is ensured to be very less. Further, scaling is also formed on the rotor discs of a turbine as a result of operation over a period of time. So, it is a difficult task to identify a bend of a rotor disc due to scaling and space constraints.
Figure 1 illustrates a perspective view of an apparatus to facilitate in inspection of a bend of a rotor disc in a turbo machine.
According to the prior art, there is provided an apparatus 100 to facilitate in inspection of a bend of a rotor disc in a turbo machine comprising a lever type dial gauge 12, a holding arm 14 and a focus light 16.
The lever type dial gauge 12 includes a measuring means 22, a contact probe 24, a dial 26, a pointer 28 and a bezel 30. The measuring means 22 is provided with a pivot at one end and a dial 26 at other end. The contact probe 24 is coupled to the pivot of the measuring means 22 free in rotation. The pointer 28 is adapted to couple over the dial 26 free in rotation. The bezel 30 is adapted to encompass and coupled to the dial 26 in free rotation.

The holding arm 14 is attached to the lever type dial gauge 12 at one end and to a tool holder of a spindle of a CNC machine at other end.
Figure 2(a) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the distal end of a rotor disc from a rotor.
Figure 2(b) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the proximal end of a rotor disc from a rotor.
The method of inspection of a bend of a rotor disc in a turbo machine in accordance with the prior art involves the steps of:
a) de-scaling of the rotor discs and the rotor;
b) locking of the holding arm 14 to a tool holder of a CNC machine;
c) adapting to touch the contact probe 24 of the lever type dial gauge 12 on the rotor disc at distal end from the rotor and applying a load;
d) rotating the bezel 30 of the lever type dial gauge 12 such that the zero position
of the dial 26 is made in line to the pointer 28 of the lever type dial gauge 12
pointing towards a reading of the dial 26 due to application of the load;
e) taking away the contact probe 24 of the lever type dial gauge 12 from contact of the rotor disc;
f) moving the lever type dial gauge 12 towards the rotor;
g) adapting to touch the contact probe 24 of the lever type dial gauge 12 on the rotor disc at proximal end from the rotor and applying the same load;
h) observing whether the contact probe 24 of the lever type dial gauge 12 touched the rotor disc or not through naked eye of an operator by illuminating the gap between the rotor discs with the help of the focus light 16; and
i) noting down the reading of traverse movement of a spindle of a CNC machine to calculate the degree of bend of the rotor disc.
The contact of the contact probe 24 of the lever type dial gauge 12 at distal end of the rotor disc from the rotor can be viewed clearly by the operator unlike contact of the contact probe 24 of the lever type dial gauge 12 at proximal end of the rotor disc from the rotor.

Therefore, there is felt a need for development of a method to facilitate in inspection of a bend of a rotor disc to overcome the drawbacks of the prior art and thereby provide an accurate and fool proof method.
OBJECTS OF THE INVENTION:
An object of the present invention is to provide a simple and easy method to facilitate in inspection of a bend of a rotor disc in a turbo machine.
Another object of the present invention is to eliminate human error in inspection of a bend of a rotor disc in a turbo machine.
One more object of the present invention is to provide a better viewing method for an operator to inspect a bend of a rotor disc in a turbo machine.
Still another object of the present invention is to provide an effective method to facilitate in inspection of a bend of a rotor disc in a turbo machine in cases of space constraints between the rotor discs.
Further another object of the present invention is to provide an accurate and fool proof method to facilitate in inspection of a bend of a rotor disc in a turbo machine.
SUMMARY OF THE INVENTION:
In accordance with the present invention an apparatus (200) to facilitate in inspection of a bend of a rotor disc in a turbo machine is provided, the apparatus (200) comprising:
(i) a lever type dial gauge (42) comprising a measuring means (62), a contact
probe (64), a dial (66), a pointer (68) and a bezel (70), the measuring means (62) adapted to couple to the dial (66) proximal to its one end and pivotally coupled to the contact probe (64) at its other end, the pointer (68) adapted to couple over the dial (66) in free rotation, the bezel (70) adapted to couple and encompass the dial (66) in free rotation and thereby facilitates in free rotation of the dial (66);

(ii) a dial gauge holding arm (44) adapted to couple to the lever type dial
gauge (42) at its one end and adapted to couple to a tool holder of a spindle of a CNC machine at its other end; and
(iii) a mirror (46) coupled to one end of a mirror holding stick (48) with the
help of a mirror attachment (50) and other end of the mirror holding stick (48) left freely for holding by an operator, the mirror holding stick (48) adapted to place beside the lever type dial gauge (42) with the help of the operator in such a way that the dial (66) and the mirror (46) are parallel and facing each other.
Typically, the contact probe (64) touched at the proximal end of the rotor disc or not is visualized in the image of the mirror (46).
In accordance with the present invention a method to facilitate in inspection of a bend of a rotor disc in a turbo machine is provided, the method comprising the steps of:
(i) descaling a rotor and a plurality of rotor discs integrally formed or attached to
the rotor; (ii) locking of a dial gauge holding arm (44) coupled with a lever type dial gauge
(42) at its one end, to a tool holder of a CNC machine; (iii) adapting to touch a contact probe (64) of the lever type dial gauge (42) on
the rotor disc at distal end from the rotor and applying a load; (iv) rotating a bezel (70) of the lever type dial gauge (42) such that the zero
position of a dial (66) is made in line to a pointer (68) of the lever type dial gauge (42) pointing towards a reading of the dial (66) due to application of the load; (v) taking away the contact probe (64) of the lever type dial gauge (42) from
contact of the rotor disc; (vi) moving said lever type dial gauge (42) towards the rotor; (vii) adapting to touch the contact probe 64 of the lever type dial gauge 42 on the
rotor disc at proximal end from the rotor and applying the same load; (viii) placing a mirror holding stick (48) beside the lever type dial gauge (42)
with the help of an operator in such a way that a mirror (46) is parallel and

facing the dial (66); (ix) observing in the image of the mirror (46) whether the contact probe (64) of the lever type dial gauge (42) touched the rotor disc or not and whether the pointer (68) point towards the zero position of the dial (66) or not because of the application of the load; and (x) noting down the reading of traverse movement of a spindle of a CNC machine to calculate the degree of bend of the rotor disc.
BRIEF DESCRIPTION OF THE DRAWINGS:
The invention will now be described with reference to the accompanying drawings in
which:
Figure 1 illustrates a perspective view of an apparatus to facilitate in inspection of a
bend of a rotor disc in a turbo machine according to the prior art;
Figure 2(a) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the distal end of a rotor disc from a rotor according to the prior art;
Figure 2(b) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the proximal end of a rotor disc from a rotor according to the prior art;
Figure 3 illustrates a perspective view of an apparatus to facilitate in inspection of a bend of a rotor disc in a turbo machine in accordance with the present invention;
Figure 4(a) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the distal end of a rotor disc from a rotor in accordance with the present invention; and
Figure 4(b) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the proximal end of a rotor disc from a rotor in accordance with the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS:
A preferred embodiment will now be described in detail with reference to accompanying drawings. The preferred embodiment does not limit the scope and ambit of the invention. The description provided is purely by way of example and illustration.
Figure 3 illustrates a perspective view of an apparatus to facilitate in inspection of a bend of a rotor disc in a turbo machine.
In accordance with the present invention, there is provided an apparatus 200 to facilitate in inspection of a bend of a rotor disc in a turbo machine comprising a lever type dial gauge 42, a dial gauge holding arm 44, a mirror 46, a mirror holding stick 48, a mirror attachment 50 and a focus light 52.
The lever type dial gauge 42 includes a measuring means 62, a contact probe 64, a dial 66, a pointer 68 and a bezel 70. The measuring means 62 is provided with a pivot at one end and a dial 66 at other end. The contact probe 64 is coupled to the pivot of the measuring means 62 free in rotation. The pointer 68 is adapted to couple over the dial 66 free in rotation. The bezel 70 is adapted to encompass and coupled to the dial 66 in free rotation and thereby facilitates in free rotation of the dial 66.
The dial gauge holding arm 44 is attached to the lever type dial gauge 42 at one end and to a tool holder of a spindle of a CNC machine at other end. The mirror holding stick 48 is provided with the mirror 46 at its one end by means of the mirror attachment 50 and the other end is free to hold by the hand of an operator.
Figure 4(a) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the distal end of a rotor disc from a rotor.
Figure 4(b) illustrates a perspective view of a contact probe of a lever type dial gauge touching at the proximal end of a rotor disc from a rotor.

The method of inspection of a bend of a rotor disc in a turbo machine in accordance with the present invention involves the steps of:
a) de-scaling of the rotor discs and the rotor;
b) locking of the dial gauge holding arm 44 to a tool holder of a CNC machine;
c) adapting to touch the contact probe 64 of the lever type dial gauge 42 on the rotor disc at distal end from the rotor and applying a load;
d) rotating the bezel 70 of the lever type dial gauge 42 such that the zero position
of the dial 66 is made in line to the pointer 68 of the lever type dial gauge 42
pointing towards a reading of the dial 66 due to application of the load;
e) taking away the contact probe 64 of the lever type dial gauge 42 from contact of the rotor disc;
f) moving the lever type dial gauge 42 towards the rotor;
g) adapting to touch the contact probe 64 of the lever type dial gauge 42 on the rotor disc at proximal end from the rotor and applying the same load;
h) placing the mirror holding stick 48 beside the lever type dial gauge 42 with the help of an operator in such a way that the mirror 46 is parallel and facing the dial 66;
i) observing in the image of the mirror 46 whether the contact probe 64 of the lever type dial gauge 42 touched the rotor disc or not and whether the pointer 68 point towards the zero position of the dial 66 or not because of the application of the load; and
j) noting down the reading of traverse movement of a spindle of a CNC machine to calculate the degree of bend of the rotor disc.
Typically, the provision of the mirror 46 facilitates the operator to ensure whether the contact probe 64 of the lever type dial gauge 42 touched the rotor disc or not and whether the same load has been applied at the proximal end of the rotor disc as that of the distal end of the rotor disc or not.
Typically, the difference in the readings of the traverse movement of a spindle of a CNC machine from point of contact at distal end of the rotor disc to point of contact at proximal end of the rotor disc gives the degree of bend of the rotor disc.

Typically, the gap between the rotor discs is illuminated with the help of the focus light 52 for clear vision of the image of the mirror 46 to the operator.
TECHNICAL ADVANCEMENTS:
An apparatus to facilitate in inspection of a bend of a rotor disc in a turbo machine and a method thereof has several technical advantages including but not limited to the realization of:
• a simple and easy method to facilitate in inspection of a bend of a rotor disc in a turbo machine ;
• a method to eliminate human error in inspection of a bend of a rotor disc in a turbo machine ;
• a better viewing method for an operator to inspect a bend of a rotor disc in a turbo machine ;
• an effective method to facilitate in inspection of a bend of a rotor disc in a turbo machine in cases of space constraints between the rotor discs ; and
• an accurate and fool proof method to facilitate in inspection of a bend of a rotor disc in a turbo machine.
Although the invention has been described herein above with reference to the embodiments of the invention, the invention is not limited to the embodiments described herein above. It is to be understood that modifications and variations of the embodiments can be made without departing from the spirit and scope of the invention.

1) An apparatus (200) to facilitate in inspection of a bend of a rotor disc
in a turbo machine, said apparatus (200) comprising :
a) a lever type dial gauge (42) comprising a measuring means (62), a contact probe (64), a dial (66), a pointer (68) and a bezel (70), said measuring means (62) adapted to couple to said dial (66) proximal to its one end and pivotally coupled to said contact probe (64) at its other end, said pointer (68) adapted to couple over said dial (66) in free rotation, said bezel (70) adapted to couple and encompass said dial (66) in free rotation and thereby facilitates in free rotation of said dial (66) ;
b) a dial gauge holding arm (44) adapted to couple to said lever type dial gauge (42) at its one end and adapted to couple to a tool holder of a spindle of a CNC machine at its other end ; and
c) a mirror (46) coupled to one end of a mirror holding stick (48) with the help of a mirror attachment (50) and other end of said mirror holding stick (48) left freely for holding by an operator, said mirror holding stick (48) adapted to place beside said lever type dial gauge (42) with the help of the operator in such a way that said dial (66) and said mirror (46) are parallel and facing each other.

2) An apparatus (200) to facilitate in inspection of a bend of a rotor disc in a turbo machine as claimed in claim 1, wherein said contact probe (64) touched at the proximal end of the rotor disc or not is visualized in the image of said mirror (46).
3) A method of to facilitate in inspection of a bend of a rotor disc in a turbo machine, said method comprising the steps of :

a) descaling a rotor and a plurality of rotor discs integrally formed or attached to said rotor ;
b) locking of a dial gauge holding arm (44) coupled with a lever type dial gauge (42) at its one end, to a tool holder of a CNC machine ;

c) adapting to touch a contact probe (64) of said lever type dial gauge (42) on the rotor disc at distal end from the rotor and applying a load ;
d) rotating a bezel (70) of said lever type dial gauge (42) such that the zero position of a dial (66) is made in line to a pointer (68) of said lever type dial gauge (42) pointing towards a reading of said dial (66) due to application of the load ;
e) taking away said contact probe (64) of said lever type dial gauge (42) from contact of the rotor disc ;
f) moving said lever type dial gauge (42) towards the rotor ;
g) adapting to touch said contact probe (64) of said lever type dial gauge (42) on the rotor disc at proximal end from the rotor and applying the same load ;
h) placing a mirror holding stick (48) beside said lever type dial gauge (42) with the help of an operator in such a way that a mirror (46) is parallel and facing said dial (66) ;
i) observing in the image of said mirror (46) whether said contact probe (64) of said lever type dial gauge (42) touched the rotor disc or not and whether said pointer (68) point towards the zero position of said dial (66) or not because of the application of the load ; and
j) noting down the reading of traverse movement of a spindle of a CNC machine to calculate the degree of bend of the rotor disc.
4) A method to facilitate in inspection of a bend of a rotor disc in a turbo machine as claimed in claim 3, wherein said mirror holding stick (48) is held in position exactly opposite to said dial (66) of said lever type dial gauge (42) with the help of an operator holding at other end.
5) A method to facilitate in inspection of a bend of a rotor disc in a turbo machine as claimed in claim 3 or 4, wherein the gap between the plurality of rotor discs is illuminated with the help of a focus light (52) for clear vision of the image of said mirror (46) to said operator.

6) A method to facilitate in inspection of a bend of a rotor disc in a turbo machine as claimed in claim 3, wherein the difference in the readings of the traverse movement of a spindle of a CNC machine from point of contact at distal end of the rotor disc to point of contact at proximal end of the rotor disc gives the degree of bend of the rotor disc.