Rotary kinetic fluid motors or pumps – Including casing part selectively movable relative to fixed...
Reexamination Certificate
1999-05-14
2001-05-01
Look, Edward K. (Department: 3745)
Rotary kinetic fluid motors or pumps
Including casing part selectively movable relative to fixed...
C415S213100, C415S214100
Reexamination Certificate
active
06224332
ABSTRACT:
TECHNICAL FIELD
The present invention relates generally to gas turbines and particularly to gas turbines having inner and outer turbine shell sections. More particularly, the present invention relates to apparatus and methods for installing and aligning the inner shell relative to the outer shell during initial assembly of the turbine, as well as removing the inner shell for maintenance and repair of component parts of the rotor and shell sections in the field and reinstalling the inner shell.
In U.S. Pat. No. 5,779,442, there is disclosed a gas turbine comprised of inner and outer shells. The inner shell carries the first and second-stage nozzles and shrouds, while the outer shell provides structural support therefor as well as support for the nozzles and shrouds of additional stages. Each of the inner and outer shells is comprised of semi-cylindrical upper and lower shell sections joined one to the other along respective horizontal splitlines. As outlined in that patent, the nozzles of the first and second stages are cooled by flowing a thermal medium into and out of the nozzles.
Access to the hot gas path components of the turbine, without removal of the rotor within the inner shell, is accomplished in that patent by disconnecting and removing various piping and fittings associated with the cooling circuit, inserting rollers through access openings in the lower outer shell to transfer the weight of the inner shell to the rollers, removing the pins mounting the inner shell to the outer shell and then removing the upper outer shell, exposing the upper inner shell section for removal. Upon disconnecting the upper inner shell section from the lower inner shell section along the horizontal splitline, the upper inner shell section including its nozzle, shroud and associated piping, can be removed from the turbine, exposing the underlying sections of the rotor. A simulated dummy shell section is then secured to the lower inner shell section at its splitline and the dummy shell and lower inner shell section are rotated 180° to locate the inner shell section above the lower outer shell section. By removing this second inner shell section, the complete inner shell can be removed for maintenance and repair without removal of the rotor.
In that patent, there is also disclosed a rolling fixture which is disposed on the lower outer shell section to facilitate removal and installation of the inner shell relative to the outer shell. The fixture mounts a winch by which the dummy shell section and lower inner shell section can be rotated about the rotor axis to facilitate removal of the lower shell section.
As will also be appreciated from a review of that patent, the inner and outer shells are connected to one another by a pair of axially spaced circumferential arrays of pins interconnecting the inner and outer shells. The pins project radially outwardly from the inner shell and have opposite circumferentially facing flats which cooperate with adjusting screws mounted on the outer shell to adjust the inner shell relative to the outer shell in a plane normal to the axis of rotation.
A new and more advanced gas turbine design has been developed by the assignee hereof which employs axially spaced arrays of rectilinear sockets about the inner shell. Pins projecting from the outer shell into the sockets to support the inner shell from the outer shell and in coaxial alignment with the rotor axis. For a complete disclosure of the geometry of the pins, reference is made to co-pending patent application Ser. No. 08/313,362, of common assignee herewith, the disclosure of which is incorporated herein by reference. These latter support pins are not adjustable by adjusting screws carried by the outer shell as in assignee's prior U.S. Pat. No. 5,779,442. There has thus developed a need for a system for installing and removing the inner shell sections relative to the outer shell and aligning the inner shell relative to the outer shell upon installation.
BRIEF SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, there is provided apparatus and methods for field removal of the inner shell relative to the outer shell without removal of the rotor and for reinstalling new or repaired inner shell sections without removal of the rotor and aligning the inner shell relative to the rotor axis in both radial and axial directions. To accomplish the foregoing, it will be appreciated that the inner and outer shells are connected one to the other by axially spaced, circumferential fore and aft arrays of support pins bolted to the outer shell at locations generally spaced 45° from one another about the outer shell and projecting radially inwardly for reception in recesses at corresponding locations along the inner shell. While eight support pins at each fore and aft axial location are preferred, a few or greater number of support pins may be used and with different circumferential spacing therebetween. For purposes of the present description and convenience only, the location of the pins is described in approximate clock positions about the rotor axis as viewed axially. To remove the inner shell, the support pins at the 5 and 7 o'clock positions, both fore and aft, are removed. An alignment fixture is then attached to and suspended from the lower outer shell section. The alignment fixture generally comprises a rectangular frame having left and right-hand outer shell mounts secured to the lower outer shell section on opposite sides of the rotor axis. The outer shell mounts connect with a depending rectangular frame by respective pairs of alignment rods on each side of the alignment fixture whereby the rectangular frame is supported solely by the pairs of alignment rods. Additionally, a pair of axially extending alignment rods interconnect the rectangular frame and the mounts and a lateral or transversely extending alignment rod interconnects the frame and one of the mounts. The rectangular frame also includes two pairs of cradle pins mounted on inclined tracks for engagement through the lower outer shell section support pin openings at the 5 and 7 o'clock positions and with the recesses in the inner shell normally mounting the support pins interconnecting the inner and outer shells. With the rectangular frame suspended from the mounts secured to the lower outer shell section, and with the cradle pins engaging in the openings of the inner shell, it will be appreciated that the entire weight of the inner shell can be transferred to the cradle pins and supported from the lower outer shell section through the rectangular frame, vertical adjusting rods and mounts.
With the mounts secured to the lower outer shell section and the cradle pins inserted into the recesses of the inner shell, the forward and aft support pins interconnecting the upper outer shell section and the upper inner shell section to one another are removed. Upon removal of the upper support pins, the upper outer shell section is removed, lifting it from the lower outer shell section at the horizontal splitline. Next, the upper inner shell section is removed. The remaining support pins at the 4 and 8 o'clock positions, both fore and aft, are then removed whereby the weight of the lower inner shell section is wholly transferred to the cradle pins, supported in turn through the alignment structure by the lower outer shell section.
To remove the lower inner shell section, roller assemblies are secured to the lower outer shell section. The rollers thereof engage the inner shell at the 4 and 8 o'clock positions. The cradle pins are then backed off, transferring the weight of the lower inner shell section to the lower outer shell section through the roller assemblies. Additional roller assemblies are then secured to the outer shell at the 5 and 7 o'clock positions with their rollers engaging the lower inner shell section. A dummy inner shell section is secured on the lower inner shell section at the splitline. A roller cage is then attached to the lower outer shell section and the dummy shell sect
Bergendahl Peter Allen
Leach David
Phelps Robert Kim
Smith Robert Leroy
Waldo Stuart Forrest
General Electric Co.
Look Edward K.
McAleenan James M.
Nixon & Vanderhye
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