Power plants – Combustion products used as motive fluid – Combined with regulation of power output feature
Reexamination Certificate
1999-10-05
2001-04-17
Casaregola, Louis J. (Department: 3746)
Power plants
Combustion products used as motive fluid
Combined with regulation of power output feature
C060S752000
Reexamination Certificate
active
06216442
ABSTRACT:
BACKGROUND OF THE INVENTION
The present invention relates to a support system for combustion liners in a gas turbine combustion system and particularly relates to supports interconnecting the upstream ends of a combustion liner to the surrounding flow sleeve or other surrounding structure for reducing wear between the contact surfaces of the parts while maintaining axial, circumferential and radial position of the liner.
In an existing system for supporting a liner within a flow sleeve, three equally spaced tab and slot arrangements are disposed about the upstream end of the combustor between the flow sleeve and liner. A tab and slot arrangement is used to ensure proper positioning of the components and to facilitate assembly. However, combustion pressure oscillations and buffeting due to external and internal air flow can result in relative motion between the tab and slot contact surfaces. This relative motion produces wear on the parts. Currently, combustion inspection intervals are determined in part by the amount of wear that can be permitted before repair is required. Extension of the inspection interval is desirable to reduce operation and maintenance costs and to increase machine availability.
Prior attempts at reducing wear focused on using wear-resistant materials and closely controlled clearances and tolerances between contacting surfaces. That design philosophy, however, has not proven completely successful in reducing wear on the combustor supports. It will be appreciated that various design constraints are imposed on the support system between the liner and the surrounding structural components For example, both relative thermal expansion and manufacturing tolerances of the flow sleeve and liner must be accommodated.
BRIEF SUMMARY OF THE INVENTION
In accordance with a preferred embodiment of the present invention, a combustion liner support system for a gas turbine combustor is provided which is highly resistant to relative motion and wear and which accommodates thermal growth and tolerance stack up between the components of the support system. In a preferred embodiment, the support system includes three equally spaced supports circumferentially spaced around the liner. Each support includes a flow sleeve stop secured to the inner surface of the flow sleeve and a liner stop secured to the outer surface of the liner. The flow sleeve stop includes an angled surface, a slot or groove and a female threaded aperture. The liner stop includes an angled surface complementary in shape to the angled surface of the flow sleeve stop and carries a tab for reception in the groove or slot of the flow sleeve stop. The liner stop includes an enlarged opening for receiving the bolt. Upon installation, the liner is received through the open upstream end of the flow sleeve such that the respective inclined surfaces of the flow sleeve stops and liner stops engage one another and the tabs engage in the slots. A pin or bolt receives a coil spring and the bolt is inserted through the liner stop opening for threaded securement in the flow sleeve threaded aperture. The spring cooperates between the bolt head and the liner stop to load the liner stop against the flow sleeve stop angled surface and hence position the liner in an axial downstream direction, maintaining contact between the inclined surfaces of the liner stops and the flow sleeve stops.
By the foregoing described arrangement, a mechanically rigid and zero clearance support system is provided for the forward end of the combustor liner that is resistant to wear and which accommodates thermal growth between the flow sleeve and liner. The angled surfaces and spring combination, in concert with the steady-state aerodynamic loading, provide sufficient downstream force on the liner to prevent separation of the angled surfaces during operation of the turbine. That is, a combination of the spring load and steady-state aerodynamic load exceed all other mechanical and dynamic loads acting on the liner during operation and ensures that the liner and flow sleeve stops remain in contact with one another. Moreover, the installation of the liners within the flow sleeve is accommodated by simple axial mating of the liner stops and the flow sleeve stops.
In a preferred embodiment according to the present invention, there is provided a gas turbine combustor comprising a liner in the combustor defining a combustor axis, a support structure carried by the combustor, a plurality of supports between the support structure and the liner at circumferentially spaced positions about the combustor, each support including a support structure stop having a first surface and a liner stop having a second surface, the support structure stop and the liner stop being secured to the support structure and the liner, respectively, and being oriented such that the first and second surfaces contact one another for supporting axial and radial loads, the support structure stop and the liner stop having respective cooperable guide surfaces for precluding circumferential movement of the support structure stop and the liner stop relative to one another and a spring engaging between the support structure stop and the liner stop for maintaining axial directed loadings on the first and second surfaces.
In a further preferred embodiment according to the present invention, there is provided for use in a combustor having an axis, liner support structure and a liner about the axis, apparatus for connecting the support structure and liner to one another adjacent an upstream end of the combustor, comprising a liner support structure stop, a liner stop for securement to the liner, the support structure stop including a first surface and a threaded aperture, the liner stop having a second surface generally complementary to the first surface of the support structure stop and an opening, the support structure stop and the liner stop being oriented such that the first and second surfaces of the support structure stop and the liner stop contact one another, with the threaded aperture and the opening generally in registration with one another, a bolt extending through the opening and threaded into the aperture, the bolt having a bolt head and a spring about the bolt between the bolt head and the liner stop for biasing the liner stop for movement in a downstream direction to maintain the liner stop second surface in substantial contact with the support structure first surface.
REFERENCES:
patent: 2748567 (1956-06-01), Dougherty
patent: 2858673 (1958-11-01), Wirt
patent: 5323600 (1994-06-01), Munshi
patent: 656012 (1951-08-01), None
Belsom Keith C.
Mohammed-Fakir Abdul-Azeez
Sims Calvin L.
Steber Charles E.
Tegel Daniel R.
Casaregola Louis J.
General Electric Co.
Nixon & Vanderhye
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