BACKGROUND

1. Field

[0001] The present application relates to gas turbines, and more particularly to a method of attaching a casing component to a combustor component, a clamping ring as well as a combustor arrangement including the clamping ring.

2. Description of the Related Art

[0002] Cylindrical components are typically attached to one another with a flanged joint. In a gas turbine, a casing component, for example, a tophat, is attached to a combustor casing with a plurality of bolts. Through holes are installed in the tophat flange and threaded holes are installed in the combustor casing to accept bolts that are installed through the tophat and into the combustor casing. Typically, approximately 24 holes, each with a corresponding bolt, per combustor casing may be used. Bolts shearing, case thread galling, and improper assembly may result in damage to threaded features and may increase the service time to the combustor casing and the outage time of the gas turbine. Incremental costs to replace the damaged components may also be an issue.

SUMMARY

[0003] Briefly described, aspects of the present disclosure relates to a clamping ring, a combustor arrangement, a method of attaching a casing component to a combustor component, a method for removal of a plurality of radially extending tabs on a combustor component flange, and a method of modification of a plurality of radially extending tabs on a combustor component flange.

[0004] A first aspect provides a clamping ring including a ring body. The ring body includes a top portion extending radially and having a thickness, a plurality of holes circumferentially arranged in the top portion and extending through the thickness, a side portion extending perpendicularly from a radial edge of the top portion and including a circumferential underside surface and a plurality of bayonet hooks protruding from the underside surface and arrangement circumferentially around the underside surface. The clamping ring also includes a plurality of fasteners protruding through a respective hole in the ring body.

[0005] A second aspect provides a combustor arrangement includes a combustor component including a flange, a casing component arranged on the combustor component flange, and a clamping ring. The clamping ring secures the casing component to the combustor component. [0006] A third aspect provides a method of attaching a casing component to a combustor component including arranging the casing component on a flange of the combustor component, installing a clamping device around the outer surface of the casing component, engaging each of a plurality of bayonet hooks of the clamping device with a corresponding mating radially extending tab of a plurality of radially extending tabs of the combustor component flange, and tightening a plurality of fasteners on the clamping device to secure the casing component to the combustor component.

[0007] A fourth aspect provides a method for removal of a plurality of radially extending tabs on a combustor component flange including arranging a machining device on the combustor component flange, aligning a cutting means of the machining device with a cutting depth of a material of each of the plurality of radially extending tabs to be removed, and removing the material of the plurality of radially extending tabs such that at least a portion of each of the plurality of radially extending tabs are removed. [0008] A fifth aspect provides a method for modifying the plurality of radially extending tabs on a combustor component flange. The method includes modifying the material of the plurality of radially extending tabs. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] FIG 1 shows a side view of a casing component attached to a combustor casing with a flanged bolted joint,

[0010] FIG 2 shows an exploded view of a casing component including through holes and the combustor casing including case bolt holes,

[0011] FIG 3 shows a side view of a clamping ring,

[0012] FIG 4 shows a cross sectional view of a bayonet hook,

[0013] FIG 5 shows a side view of the combustion component flange,

[0014] FIG 6 shows a side view of a combustor arrangement, and

[0015] FIG 7 shows a cross sectional view of the combustor arrangement according to FIGs 3 and 6.

DETAILED DESCRIPTION

[0016] To facilitate an understanding of embodiments, principles, and features of the present disclosure, they are explained hereinafter with reference to implementation in illustrative embodiments. Embodiments of the present disclosure, however, are not limited to use in the described systems or methods.

[0017] The components and materials described hereinafter as making up the various embodiments are intended to be illustrative and not restrictive. Many suitable components and materials that would perform the same or a similar function as the materials described herein are intended to be embraced within the scope of embodiments of the present disclosure.

[0018] A method, a clamping ring, and a combustor arrangement to attach a casing component to a combustor casing are provided. For illustrative purposes, the casing component is described hereinafter as a tophat component that attaches to a combustor casing. This method and arrangement could eliminate the threaded features in the combustor casing. Elimination of the threaded features may result in a shorter turnaround time to service the combustor as each time the casing component is removed, a plurality of fasteners need to be removed which potentially can be, for example, 24 bolts per combustor and with 16 combustors per engine typically, approximately 384 bolts may need to be removed. In addition, the elimination of the bolts and the corresponding washers may also have a cost saving by not including this additional hardware. Furthermore, machining the combustor casing in order to include the holes for the fasteners and/or eliminate faulty threads may be dispensed with using the provided arrangement and method. It will be appreciated to one skilled in the art, while the embodiments are described in terms of a tophat, that the attachment method and arrangement may be desirable anywhere a flanged joint arrangement is used. Therefore, any flanged component may be used. [0019] A clamping ring is also provided. The clamping ring may fit around the outer surface of the casing component. The clamping ring includes a plurality of holes into which a plurality of fasteners are inserted and tightened securing the tophat to the combustor component. As the clamping ring includes the plurality of holes instead of the tophat flange, the flange on the tophat may be much narrower than the conventional tophat flange which includes the plurality of holes. The clamping ring may also include a plurality of bayonet hooks that are inserted into clearance slots on the combustor flange.

[0020] FIG 1 illustrates a side view of a conventional attachment (10) of a combustor casing (30) to a tophat component (20). Conventionally, the attachment of the tophat component (20) to a combustor casing (30) uses a flanged joint (40) where the tophat flange (50) is secured by fasteners (60). FIG 2 shows an exploded view of the tophat (20) and the combustor casing (30) with a plurality of bolts (60) before inserting them through the corresponding holes (70) in the tophat (20) and holes in the combustor casing (80). According to this illustration, the bolts (60) are evenly spaced around the circumference of the tophat flange (50).

[0021] FIG 3 illustrates a side view of a clamping ring (100). The clamping ring (100) includes a ring body and a plurality of fasteners (110). The ring body includes a top portion (140) and a side portion (135). The top portion (140) extends radially and includes a thickness. The top portion includes a plurality of holes extending through the thickness and arranged circumferentially around the top portion (140). The side portion (135) extends perpendicularly from a radial edge of the top portion (140) and includes a circumferential underside surface (150). Protruding from the underside surface (150) is a plurality of bayonet hooks (125). In the illustrated embodiment, the plurality of bayonet hooks (125) is located around the circumference of the underside surface (150). [0022] A plurality of fasteners (110) may protrude through a respective hole in the top portion (140). In the illustrated embodiment the plurality of fasteners (110) are arranged around the circumference of the top portion (140). The fasteners may be bolts, screws, rivets, tapered pins, and/or pins. Each of the respective holes in the top portion (140) may include threads into which the fasteners may be, for example, threaded into the ring body.

[0023] As shown in the embodiment of FIG 4, each of a plurality of bayonet hooks (125) may include an L-shaped hook which may be arranged radially or tangentially around the circumference of the clamping ring (100). The L-shaped hook includes a mating surface (160) and an outer surface (170) opposite the mating surface (160). The outer surface includes a length (li).

[0024] Illustrated in FIG 5 is of a combustion component flange (250) on the combustor component (230). In an embodiment, the combustor component flange (250) includes a plurality of radially extending tabs (210) spaced around the circumference of the combustor component flange (250). The radially extending tabs (210) may be evenly or unevenly spaced around the circumference of the combustor component flange (250). Each radially extending tab (210) includes a top surface (240) and a bottom surface (270). The combustion component flange (250) may also include a plurality of clearance slots (220) disposed between adjacent radially extending tabs (210). Each of the plurality of clearance slots (220) in the illustrated embodiment includes a length (1 ₂ ). In an embodiment, the length (1 ₂ ) of each of the clearance slots (220) is at least long enough to accommodate the length (li) of the outer surface (170) of the L-shaped hook. The combustion component flange (250) may include a spigot (200) positioned radially behind the radially extending tab (210), on the interior of the combustion component flange (250). The surface of the spigot (200) is at a different height than a top surface (240) of radially extending tabs (240) in the axial direction (260).

[0025] FIG 6 illustrates an embodiment of a combustor arrangement (300) including a clamping ring (100). The combustor arrangement (300) includes the combustor component (230), a tophat component (320), and the clamping ring (100). The tophat component (320) is arranged on the combustion component flange (250). The clamping ring (100) surrounds an outer surface (310) of the tophat component (320) and secures the tophat (320) to the combustor component (230).

[0026] The tophat component, as shown in FIG 6, (320) comprises a cylindrical element (340) with a bottom surface which may extend to and abut the combustion component flange (250). The bottom surface of the cylindrical element (340) includes a notch which abuts the spigot (200). The tophat (320) also includes a shallow flange on which a fastener may rest.

[0027] In the illustrated embodiment, each of the bayonet hooks (125) engages with a radially extending tab (210) on the combustor component (230) securing the tophat (310) to the combustor component (230). The bottom surface (270) of the radially extending tab (210) may mate with a mating surface (160) of the L-shaped hook such that the bottom surface (270) is in contact with a corresponding mating surface (160). In an embodiment, the overlap of the two surfaces is enough to provide a secure interface so that an appropriate amount of contact pressure exists between the two contacted surfaces (160, 270) without sliding or bending. [0028] When the plurality of fasteners (110) are fastened in the clamping ring (100), the bayonet hooks (125) engage with the radially extending tabs (210) producing a reacting force on the tophat flange forcing it against the combustor component flange (250).

[0029] FIG 7 shows a cross section through the combustor arrangement (300) from the embodiments shown in FIGs 3 and 6. In the illustrated embodiment, the fastener (110) is shown in cross section extending through a respective hole (400) in the top portion (140) of clamping ring (100). When fastened, each fastener (110) abuts the tophat flange (450) and provides a clamping force to assist in securing the tophat (320) to the combustor component (230).

[0030] FIG 7 illustrates an embodiment the engagement (460) of the radially extending tab (210) with the bayonet hook (125) is shown. For the engagement (460), the bottom surface (270) of the radially extending tab (210) is mated with the mating surface (160) of the L-shaped hook (125). [0031] In an embodiment, the spigot (200) on the combustion component flange (250) positioned radially behind the radially extending tab (210), on the interior of the combustion component flange (250). A notch (420) in the tophat (320) may be arranged on the spigot (200) of the combustor component (230) to provide a sealing interface (470). The sealing interface (470) contributes to the overall sealing between the tophat component (320) and the combustor component (230).

[0032] Referring to FIGs 1-7, a method for attaching a casing component, also known as the tophat (320), to a combustor component (230) is also provided. In an embodiment, the tophat component (320) may be loosely arranged on the combustor component flange (250). The notch (420), the radially interior portion of the bottom surface of the tophat (320), may be centered on the spigot (200) portion of the combustor component flange (250). The spigot (200) is a portion of the combustor component flange (250) that is at a different height, in the axial direction (260) than the remaining radially exterior portion of the combustor component flange (250). The spigot (200) helps to keep the tophat (320) centered on the combustor component flange (250) and also contributes to sealing the interface (470). The remaining portion of the bottom surface of the tophat (320) may be disposed on the combustor component flange (250) to the interior of the radially extending tabs (210). This positioning may be seen in FIG 7.

[0033] The clamping ring (100) may be installed around the outer surface (310) of the tophat (320). [0034] In order to engage the plurality of bayonet hooks (125) of the clamping ring (100) with the radially extending tabs (210) of the combustor component flange (250), the plurality of bayonet hooks (125) of the clamping ring (100) may be lined up with a respective clearance slot (220) on the combustor component flange (250). Each bayonet hook (125) would then be inserted into the respective clearance slot (220) on the flange (250) until the mating surface (160) of the bayonet hook (125) would be able to slide past the bottom surface (270) of the radially extending tab (210) in the circumferential direction.

[0035] To provide the engagement, the clamping ring (100) may be rotated. During the rotation, the mating surface (160) makes contact with, is mated with, a corresponding bottom surface (270) of the radially extending tab (210). The rotation would be complete when the bottom surface (160) is in contact with a corresponding mating surface (160) and the overlap of the two surfaces would be enough to provide a secure interface. A secure interface is one in which an appropriate amount of contact pressure exists between the two contacted surfaces (160, 270) without sliding or bending. In the illustrated embodiment shown in the Figures a clockwise rotation would be used. However, one skilled in the art would appreciate that when the bayonet hooks (125) face in the opposite direction to the one shown a counter clockwise direction would be used. [0036] After the plurality of bayonet hooks of the clamping device (100) have mated with the radially extending tabs (210), the plurality of fasteners (110) may then be tightened in order to more fully secure the casing component (320) to the combustor component (230). Fasteners such as bolts, screws, pins, tapered pins or rivets may be inserted through the corresponding holes in the clamping device and may be secured by a nut.

[0037] In the illustrated embodiments the bayonet hooks (125) are shown as extending tangentially in relation to the circumference of the clamping ring (100). However, one skilled in the art would appreciate that the bayonet hooks (125) may also extend radially. [0038] The method provides a quicker way to attach the tophat component (320) to the combustor component (230). Additionally, the method provides a way to attach the tophat component (320) to the combustor component (230) without drilling holes directly into the combustor component (230), which is a costly component, in order to provide holes for the flanged joint (40). In an embodiment where the clamping ring (100) is used instead of a flanged joint (40), the holes are in a removable clamping ring (100) that can easily be removed and repaired instead of in the flanged joint (40).

[0039] A method is also provided to remove the radially extending tabs (210) of a combustor component flange (250). This method could be used in the case that it may be necessary to return to a conventional arrangement (10) from a combustor arrangement (300) of a tophat (320) and a combustor component (230). In order to remove the plurality of radially extending tabs (210), machining may be used. In an embodiment, a machining device is arranged on the combustor component (230). The machining device would include a mill, a laser, a torch, for example. The cutting means of the machining device, such as a laser beam of a laser, may be aligned with a desired cutting depth of a material of the plurality of radially extending tabs (210) to be removed. The cutting means would then be used to remove a portion of the material of the plurality of radially extending tabs (210). In an embodiment, aligned holes may then be drilled into the combustor component (230) and fasteners inserted for attachment of the combustor component (230) to a tophat component (320). In another embodiment, all of the material of the plurality of radially extending tabs (210) may be removed.

[0040] Alternately, the radially extending tabs (210) may be modified instead of completely removed. The modification may include drilling a hole into which a fastener would be placed.

[0041] While embodiments of the present disclosure have been disclosed in exemplary forms, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made therein without departing from the spirit and scope of the invention and its equivalents, as set forth in the following claims.