Patent Application
20130330204
The present application and the resultant patent relate generally to turbo-machinery and more particularly relate to a turbine rotor and blade assembly for use with a steam turbine having a multi-piece locking blade for reduced stress concentrations therein.
Steam turbine airfoils or buckets generally are positioned about a rotor at regular intervals in a bucket assembly. The bucket assembly may be created by inserting the buckets one at a time tangentially into an opening on the rotor and then sliding the buckets circumferentially about the rotor. The buckets may be attached to the rotor by complementary male and female dovetails and other configurations. In order to close the bucket assembly, however, the last bucket must be restrained by a feature other than a dovetail. This last bucket, generally called the locking blade or the closure bucket, may be affixed to the rotor via one or more blade retention screws and the like tapped or screwed into the rotor. Other types of connection means and other types of bucket assemblies also may be used.
Large centrifugal loads may be placed on the buckets and the rotor during operation. Such centrifugal loads and coincident thermally induced loads associated with loading transients may induce stresses in the dovetails and adjacent areas that attach the buckets to the rotor. These stresses may be of sufficient magnitude to impact adversely rotor cycle fatigue life. Of particular concern may be rotor stress concentrations associated with blade retention screws that may be tapped or otherwise inserted directly into the rotor.
There is thus a desire for an improved turbine rotor and blade assembly for a steam turbine and the like. Preferably such an improved turbine rotor and blade assembly may reduce stress concentrations therein for an improved overall rotor fatigue life.
The present application and the resultant patent thus provide herein a turbine rotor and blade assembly for a steam turbine. The turbine rotor and blade assembly may include a rotor, a number of buckets positioned about the rotor, and a locking blade positioned about the rotor. The locking blade may include a multi-piece configuration.
The present application and the resultant patent further provide a multi-piece locking blade for use with a rotor. The multi-piece locking blade may include a base, a first side hook on a first side of the base, and a second side hook on a second side of the base.
The present application and the resultant patent further provide a steam turbine. The steam turbine may include a rotor, a number of buckets positioned about the rotor, and a multi-piece locking blade positioned about the rotor. The multi-piece locking blade may include a base, a first side hook, and a second side hook.
These and other features and improvements of the present application and the resultant patent will become apparent to one of ordinary skill in the art upon review of the following detailed description when taken in conjunction with the several drawings and the appended claims.
Referring now to the drawings, in which like numerals refer to like elements throughout the several views,
In use, a flow of steam 70 passes through the steam inlets 60 and into the sections 15, 20 such that mechanical work may be extracted from the steam by the stages therein so as to rotate the rotor shaft 40. The flow of steam 70 then may exit the sections 15, 20 for further processing and the like. The steam turbine 10 described herein is for the purpose of example only. Steam turbines and/or other types of turbo-machinery in many other configurations and with many other or different components also may be used herein.
As is shown in
As is shown in
In use, the buckets 140 of the rotor and blade assembly 110 may be positioned about the rotor 120 within the dovetail slot 130 as is described above. When all of the buckets 140 have been positioned thereon, the locking blade 170 may be inserted. Specifically, the hooks 240, 250 may be inserted within the locking blade groove 300 in the rotor 120. The base 190 then may be inserted between the hooks 240, 250. The base 190 then may be secured by inserting the side screws 280, 290 between the base screw threads 200, 220 and the hook screw threads 270. The rotor and blade assembly 100 thus may be secure. The rotor and blade assembly 110 also may be disassembled in reverse order.
The locking blade 170 with the multi-piece configuration 175 thus may improve the overall fatigue life of the turbine rotor blade assembly 110. Specifically, the use of the multi-piece configuration 175 may avoid inherent rotor stress concentrations that may be caused by the small radius of a tapped hole when using blade retention screws and the like. Rather, the multi-piece configuration 175 uses the hooks 240, 250 within the locking blade groove 300 of the rotor 120 without requiring the use of screws tapped or otherwise inserted into the rotor 120. The multi-piece configuration 175 thus may improve the fatigue life of the rotor 120 and related components for an extended component lifetime.
It should be apparent that the foregoing relates only to certain embodiments of the present application and the resultant patent. Numerous changes and modifications may be made herein by one of ordinary skill in the art without departing from the general spirit and scope of the invention as defined by the following claims and the equivalents thereof.
