DETAILED DESCRIPTION

[0012] FIG. 1 is a partial perspective view of a steam turbine 10 including a rotor assembly 12 and a stator assembly 14. Rotor assembly 12 includes a shaft 16 and a plurality of bucket assemblies 18. Each bucket assemblies 18 include a plurality of buckets 20 arranged in rows extending circumferentially around shaft 16.

[0013] Stator assembly 14 includes a stator 22 and a plurality of nozzle assemblies 28. Nozzle assemblies 28 include a plurality of nozzles 30 arranged in rows extending inward circumferentially around stator 22. Nozzles 30 cooperate with buckets 20 to form a turbine stage and to define a portion of a steam flow path through turbine 10.

[0014] In operation, steam 24 enters an inlet 26 of turbine 10 and is channeled through nozzles 30. Nozzles 30 direct steam 24 downstream against buckets 20. Steam 24 passing through the turbine stages imparts a force on buckets 20 causing shaft 16 to rotate. At least one end of turbine 10 may extend axially away from shaft 16 and may be attached to a load or machinery (not shown), such as, but not limited to, a generator, and/or another turbine. Accordingly, a large steam turbine unit may actually include several turbines that are all co-axially coupled to the same shaft 16. Such a unit may, for example, include a high-pressure turbine coupled to an intermediate-pressure turbine, which is coupled to a low-pressure turbine. In one embodiment, steam turbine 10 is commercially available from General Electric Power Systems, Schenectady, N.Y.

[0015] FIG. 2 is an enlarged schematic cross-sectional view of a portion of turbine engine 10 shown in Figure including rotor assembly 12 and stator assembly 14. Each stator assembly 14 includes a plurality of dovetail slots 32 and channels 33, and at least one radial load pin 34. Dovetail slots 32 are circular or arcuate in configuration when viewed axially and facilitates coupling each nozzle assembly 28 to stator 22. Dovetail slots 32 are defined by a first side slot wall 35 and a second side slot wall 36 and a radially inward slot wall 37. Substantially annular retaining rings 38 extend from each side slot wall 35 and 36. Channels 33 are generally complimentary in shape to load pins 34. In the exemplary embodiment, a pair of channels 33 extend along each inward slot wall 37 configured to receive at least one radial load pin 34.

[0016] Nozzle assemblies 28 include nozzles 30 that each include an airfoil 42 that extends between a radially outer band 44 and a radially inner band 46. Nozzle dovetail 40 extends radially outward from airfoil 42. Airfoil 42 includes a first contoured sidewall 48 and second contoured sidewall 50. First sidewall 48 is convex and defines a suction side of airfoil 42. Second sidewall 50 is concave and defines a pressure side of airfoil 42. Sidewalls 48, 50 are joined at a leading edge 52 and at an axially spaced trailing edge 54 of airfoil 42.

[0017] Nozzle dovetail 40 is generally complimentary in shape to stator dovetail slots 32. Nozzle dovetail 40 includes an upstream side 56 and a downstream side 58. In the exemplary embodiment, upstream side 56 and downstream side 58 are parallel. Nozzle assemblies 28 has a first axial face 60 and an opposite second axial face 62 that each extend between upstream and downstream sides 56, 58. Upstream side 56 includes a side shoulder 64, known as an outer tang, that extends substantially perpendicularly from upstream side 56 and defines an overhang 66. A dovetail tang 68 also extends substantially perpendicularly from the upstream side 56 and is substantially parallel to the side shoulder 64, such that an upstream side slot 70 is defined between dovetail tang 68 and shoulder 64.

[0018] Nozzle assembly downstream side 58 includes a side shoulder 72 that extends substantially perpendicularly from downstream side 58. In an exemplary embodiment, shoulder 72 is substantially co-axially aligned with respect to upstream shoulder 64. Side shoulder 72 defines a downstream side overhang 74. A dovetail tang 76 also extends substantially perpendicularly from the downstream side 58 and is substantially parallel to side shoulder 72, such that a downstream side slot 78 is defined between. In the exemplary embodiment, downstream dovetail tang 76 is substantially co-axially aligned with respect to upstream dovetail tang 68.

[0019] During assembly of stator assembly 14, each respective nozzle assembly 28 is inserted into dovetail slot 32, then circumferentially slid through dovetail slot 32. Nozzle assemblies 28 are then secured to stator 22 by inserting at least one radial load pin 34 into at least one channel 33. Additional nozzle assemblies 28 are then slidably coupled to stator assembly 14 in a similar fashion about stator 22.

[0020] Load pin 34 is substantially elongate, and is disposed in channel 33 having a substantially semi-circular cross-sectional profile. In one embodiment, channel 33 extends from slot wall 37 through dovetail slot 32. Load pin 34 secures each nozzle assembly 28 to stator 22.

[0021] FIG. 3 is an enlarged cross-sectional side view of load pin 34 used in the turbine nozzle assembly 28 shown in FIG. 2. FIG. 4 is an end view of load pin 34 shown in FIG. 3. Load pin 34 includes a first end 100, a second end 102, and a body 104 extending therebetween. Load pin 34 has a substantially semi-circular cross-sectional profile that includes a substantially circular portion 106 with a center point 107 and a radius 108, and a substantially straight portion 110. Load pin 34 further includes a length 112 and a height 114. In the exemplary embodiment, radius 108 is approximately 0.158, length 112 is approximately 0.920, and height 114 is approximately 0.200. In one embodiment, radius 108 is approximately between 0.157 and 0.159, length 112 is approximately between 0.915 and 0.925, and height 114 is approximately between 0.198 and 0.202. In another embodiment, radius 108 is approximately between 0.153 and 0.163, length 112 is approximately between 0.910 and 0.930, and height 114 is approximately between 0.195 and 0.205. In the exemplary embodiment, load pin 34 is fabricated from brass. In another embodiment, load pin 34 is fabricated from bronze. In an alternate embodiment, load pin 34 is fabricated from steel.

[0022] The above-described stator assembly is efficient and cost-effective device. The stator assembly includes a radial load pin that facilitates securing a nozzle assembly to the stator assembly, thus reducing the chances of unpredictable flow path dynamics. Furthermore, the radial load pin is inexpensive and easy to manufacture. As a result, the radial load pin facilitates stabilizing flow path dynamics in an efficient and cost-effective manner.

[0023] Exemplary embodiments of stator and nozzle assemblies are described above in detail. The systems are not limited to the specific embodiments described herein, but rather, components of each assembly may be utilized independently and separately from other components described herein. Each stator and nozzle assembly component can also be used in combination with other stator and nozzle assemblies and turbine components.

[0024] While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.