Patent Application
20100019460
This invention relates generally to rotary machine technology, and more specifically, to a new gasket construction for a turbine combustor end cover or casing.
Gaskets are typically employed in turbine combustor systems to seal the interface between various combustor components, e.g., combustor end covers and combustor casings, in order to prevent leakage of combustion gases. Currently, such gaskets are composed of graphite serviceable in a range of about 850° F. to 1050° F. in normal environments. However, the graphite gasket material has been known to degrade at temperatures as low as 450° F., apparently due to exposure to combustion gases. There remains a need, therefore, for a gasket construction for use in gas turbine combustion systems that is not subject to the leaking issues currently experienced on a regular basis with graphite gaskets.
In one exemplary but nonlimiting aspect, the present invention relates to a gasket assembly comprising: a core of compressible sealing material, the core having top and bottom surfaces and inner and outer edges; a first cover component enclosing at least the outer edge of the core; and a second cover component enclosing the inner edge of the core and extending into overlapping relationship with the first cover component.
In another aspect, the invention relates to a gasket assembly comprising: a closed periphery core of compressible sealing material, the core having upper and lower planar surfaces and radially inner and outer edges; a first cover component enclosing the radially outer edge and a relatively minor portion of the upper and lower planar surfaces; a second cover component enclosing the radially inner edge and a relatively major portion of the upper and lower planar surfaces, wherein upper and lower sides of the second cover component overlap upper and lower sides of the first cover component; and further wherein free edge portions of the second cover component are formed to include hollow, continuous annular ribs, respectively, projecting away from the closed periphery core.
In still another exemplary but nonlimiting aspect, the invention relates to a method of sealing adjacent, annular bolt flanges on respective machine components comprising: forming an annular gasket groove in one of the bolt flanges; providing an inner core of compressible sealing material; enclosing the inner core with a pair of cover components, one having a radially outer edge and first upper and lower sides, and the other having a radially inner edge and second upper and lower sides that overlap the first upper and lower sides, free end portions of the second upper and lower sides formed to include respective continuous, hollow ribs projecting away from the inner core, the free end portions engageable with the first upper and lower sides; inserting the gasket assembly in the groove; and securing the bolt flanges.
The invention will now be described in connection with the drawings identified below.
With reference initially to
Turning to
A substantially C-shaped second outer cover component 50 having an inner edge 52 and upper and lower sides 54, 56 encloses the inner edge 30 of the core 28, extending over the remaining major portions of the top and bottom surfaces 34, 36 of the core and overlapping the upper and lower sides 42, 44 of the platen ring 38.
The outer cover component 50 is preferably constructed of a softer metal such as copper, and the upper and lower sides 54, 56 thereof are formed with embossments 58, 60 adjacent free edges 62, 64 thereof. The embossments 58, 60 comprise continuous hollow ribs that extend about the entire closed periphery of the gasket. Note that the free edges 62, 64 terminate short of, but adjacent the outer edge 40 of the platen ring 38. Thus, the inner and outer components 38, 50 may be assembled about the core 28 by pushing the inner and outer components 38, 50 over the core 28 from opposite directions such that the upper and lower sides 54, 56 of the outer component 50 overlap the upper and lower sides 42, 44 of the inner component 38.
When installed, the inner edge 52 of the outer cover component 50 and the inner edge 40 of the platen ring 38 will engage the inner and outer walls 22, 24 of the groove 18. When a matching bolt flange of another component (not shown) is applied to the bolt flange 12 and tightened, the gasket assembly 26 will be fully seated in the groove 18, and embossments 42, 44 will be compressed and deformed as needed to conform with surface irregularities on the opposed bolt flanges. At the same time, the graphite core 28 remains fully enclosed and thus protected from harmful combustion gases. Note that the heavier first, inner cover component or platen ring 38 allows the embossments 42, 44 to be compressed onto a solid backing (I.e., the platen ring) as the gasket is installed, preventing damage to the core 28. In addition, by terminating the free edges 62, 64 of the second cover component 50 short of the inner edge 40 of the platen ring 38, space is provided for some radial expansion of the embossed edges under compression, uninhibited by the outer groove wall 24, best appreciated from
The ability of the gasket assembly 26 to conform to surface irregularities and to also protect the inner graphite core 28 from exposure to harsh conditions, substantially eliminates leakage issues experienced with unprotected graphite gaskets.
It will be appreciated that the gasket construction need not be of a closed periphery design, but may also be used where other machine components are joined, with gaskets required only in certain areas thereof.
While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.
