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EP-4442963-B1 - TURBINE BLADE ASSEMBLY AND TURBINE SYSTEM

EP4442963B1EP 4442963 B1EP4442963 B1EP 4442963B1EP-4442963-B1

Inventors

  • CERVETTO, FEDERICO
  • Mata López, Salvador
  • BURDGICK, STEVEN SEBASTIAN

Dates

Publication Date
20260513
Application Date
20240311

Claims (10)

  1. A turbine blade assembly (400) for a rotor groove (410) extending in a circumferential direction defined in a rotor (412) having an axis (A), the turbine blade assembly (400) comprising: a turbine blade (402) including an airfoil (416) and a dovetail (404) coupled to the airfoil (416), the dovetail (404) including a mounting arm (420) and an end surface (422) facing radially inward relative to the axis; and an extension insert (406) including a first end (424) configured to contact the end surface (422) of the dovetail (404) and a second end (426), the second end (426) including at least one of a plurality of positioning legs (428) extending radially inward relative to the axis (A), wherein the dovetail (404) and the extension insert (406) are configured to be positioned in the rotor groove (410) to mount the turbine blade (402) to the rotor (412), characterized in that at least two of the plurality of positioning legs (428) have different lengths.
  2. The turbine blade assembly (400) of claim 1, wherein the mounting arm (420) engages a radially inward facing rotor hook (430) of the rotor groove (410) and the least one positioning leg (428) engages one of a radially outward facing surface (432) of the rotor groove (410) and a planar plate shim (440) between the at least one positioning leg (428) and the radially outward facing surface (432) of the rotor groove (410).
  3. The turbine blade assembly (400) of claim 1, wherein the extension insert (406) has a radial extent larger than 4 millimeters.
  4. The turbine blade assembly (400) of claim 3, further comprising at least one planar plate shim (440) between the at least one positioning leg (428) and the radially outward facing surface (432) of the rotor groove (410), the at least one planar plate shim (440) having a radial extent of no greater than 1.5 millimeter.
  5. The turbine blade assembly (400) of claim 1, further comprising a fixation element (450) locking a position of the extension insert (406) relative to the dovetail (404) of the turbine blade (402).
  6. The turbine blade assembly (400) of claim 5, wherein the fixation element (450) includes a male-female coupler.
  7. The turbine blade assembly (400) of claim 6, wherein a female portion (452) of the male-female coupler is defined in the end surface (422) of the dovetail (404), and a male portion (454) of the male-female coupler extends from the first end (424) of the extension insert (406) and is configured to seat within the female portion (452) in the end surface (422) to lock a position of the extension insert (406) relative to the dovetail (404) of the turbine blade (402).
  8. The turbine blade assembly (400) of claim 5, wherein the fixation element (450) includes a fastener (460) coupling the end surface (422) of the dovetail (404) and the first end (424) of the extension insert (406) together.
  9. The turbine blade assembly (400) of claim 1, wherein the extension insert (406) includes a lighter material than a material of the airfoil (416) and the dovetail (404).
  10. A turbine system comprising a turbine including at least one turbine blade assembly (400) of claim 1.

Description

TECHNICAL FIELD The disclosure relates generally to turbine systems. More specifically, the disclosure relates to a turbine blade and a turbine blade assembly for a turbine system with a dovetail arrangement for an enlarged rotor groove. The present invention relates to a turbine blade assembly and to a turbine system. BACKGROUND Turbine systems include stationary nozzles that direct the flow into rotating blades connected to a rotor. The stationary nozzles (airfoil) are typically called a stationary blade, diaphragm, or nozzle assembly stage. The rotating blades receive steam flow, e.g., combustion gases or steam, from the nozzles that forces the blades to turn the rotor. Blades are generally assembled to the rotor using a base having a dovetail that mates with a groove in the rotor and is forced radially outward using thin, plate shims to help create a tight (packed) assembly. During turbine service outages, certain rotating blade stages may need to be replaced. To ensure proper assembly, the rotor groove may also need to be re-machined to clean up and eliminate any possible damage, e.g., minor cracks or other deformations. The depth of the re-machining of the rotor groove depends on the life consumption of the rotor and may vary between, for example, different locations on the rotor, different blade stages, or different turbine systems. The inside of the rotor groove may be machined to remove, for example, between two and fifteen millimeters, to eliminate any cracked or aged material and increase the lifespan of the rotor. It is a challenge to provide a new blade with a dovetail that fits the new, larger rotor groove, but does not include more weight than the original blade to avoid increased centrifugal forces and stresses on the rotor groove. DE 1 085 643 B discloses a turbine blade assembly with a rotor extending along an axis and having grooves extending in a circumferential direction. Turbine blades can be inserted into the grooves. A positioning leg can extend radially inward relative to the axis of the rotor. The turbine blade assembly disclosed in EP 2 320 030 A1 comprises a rotor having a rotor groove extending in a circumferential direction in which turbine blades are arranged. The root of the turbine blade comprises a radially inward root extension. Between the bottom of the groove and the root extension a spring may be arranged. US 2005/0207892 A1 relates to a turbine blade assembly having a rotor in which a groove extends in circumferential direction. A root portion of a turbine blade can be inserted into the groove. A leaf spring is arranged between the root portion of the rotor blade and the bottom of the blade groove. US 2011/171031 A1 proposes to provide threaded holes inside a root of a rotating turbine blade, which are inclined toward each other. Screws can be threaded therein for projecting out of the root adjacent to a groove bottom of a rotor groove. At the groove bottom inclined flanks are provided, wherein each flank faces one projecting end of a screw. The screws can be adjusted so as to contact the assigned inclined flank. Further turbine blade assemblies are known from GB 279 312 A, US 2009/214349 A1, US 2014/234111 A1, US 2019/218920 A1 and US 4 875 830 A. BRIEF DESCRIPTION The invention refers to a turbine blade assembly according to claim 1. All advantageous aspects of the claimed invention can be combined in any technically possible way. Another aspect of the disclosure includes any of the preceding aspects, and the mounting arm engages a radially inward facing rotor hook of the rotor groove and the least one positioning leg engages one of a radially outward facing surface of the rotor groove and a planar plate shim between the at least one positioning leg and the radially outward facing surface of the rotor groove. Another aspect of the disclosure includes any of the preceding aspects, and the extension insert has a radial extent larger than 4 millimeters. Another aspect of the disclosure includes any of the preceding aspects, and further comprising at least one planar plate shim between the at least one positioning leg and the radially outward facing surface of the rotor groove, the at least one planar plate shim having a radial extent of no greater than 1.5 millimeter. Another aspect of the disclosure includes any of the preceding aspects, and further comprising a fixation element locking a position of the extension insert relative to the dovetail of the turbine blade. Another aspect of the disclosure includes any of the preceding aspects, and the fixation element includes a male-female coupler. Another aspect of the disclosure includes any of the preceding aspects, and a female portion of the male-female coupler is defined in the end surface of the dovetail, and a male portion of the male-female coupler extends from the first end of the extension insert and is configured to seat within the female portion in the end surface to lock a position of the extension insert rela