The present subject matter relates generally to fastener assemblies and, more particularly, to a fastener assembly for coupling a transition piece to a portion of a gas turbine.
In a gas turbine, hot gases of combustion flow from an annular array of combustors through a transition piece for flow along an annular hot gas path. Turbine stages are disposed along the hot gas path such that the hot gases of combustion flow from the transition piece through first-stage nozzles and buckets and through the nozzles and buckets of follow-on turbine stages. The first-stage nozzles typically include an annular array or assemblage of cast nozzle segments each containing one or more nozzle stator vanes per segment. Additionally, an annular retaining ring is typically positioned around the outer circumference of the first-stage nozzles and is configured to support the nozzles radially in the hot gas path of the turbine.
Current transition pieces are configured to be coupled to the retaining ring via a bracket bolted between the retaining ring and an aft frame of the transition piece. However, due to assembly space constraints, physical access to such bracket is typically limited. As a result, the bolts used to secure the bracket between the aft frame and the retaining ring must be inserted within the bracket prior to aligning each transition piece relative to the retaining ring. This can result in the bolts being knocked out and/or falling from the bracket as the transition piece is being installed. Moreover, because a portion of each bolt must extend outside the bracket to permit the bolt to be secured to the retaining ring, the bolts may be damaged (e.g., by rubbing against and/or contacting the retaining ring) during the installation process.
Accordingly, a fastener assembly that allows for a bolt or other fastener to be retained within the bracket and/or retracted within the bracket during installation and/or removal of a transition piece would be welcomed in the technology.
Aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention.
In one aspect, the present subject matter is directed to a system for coupling a transition piece within a gas turbine. The system may generally include a transition piece aft frame and a bracket coupled to the transition piece aft frame. The bracket may define an opening extending between a first end and a second end. In addition, the system may include a fastener having a head positioned proximal to the first end of the opening and a body extending at least partially within the opening. The body may include a shank portion, a threaded portion opposite the shank portion and a recessed portion defined between the shank portion and the threaded portion. The system may also include a retention member positioned within the opening adjacent the recessed portion. The retention member may be configured to engage at least one of the shank portion or the threaded portion as the fastener is moved within the opening. Moreover, the system may include a biasing member positioned within the opening. The biasing member may be configured to bias the head of the fastener away from the first end of the opening.
In another aspect, the present subject matter is directed to a fastener assembly configured for use within an opening defined in a transition piece bracket, wherein the opening extends between a first end and a second end. The fastener assembly may generally include a fastener having a head configured to be positioned proximal to the first end of the opening and a body configured to extend at least partially within the opening. The body may include a shank portion, a threaded portion opposite the shank portion and a recessed portion defined between the shank portion and the threaded portion. The fastener assembly may also include a retention member configured to be positioned within the opening adjacent the recessed portion such that the retention member engages at least one of the shank portion or the threaded portion as the fastener is moved within the opening. In addition, the fastener assembly may include a biasing member engaged against the retention member. The biasing member may be configured to bias the head of the fastener away from the first end of the opening.
In a further aspect, the present subject matter is directed to a fastener assembly configured for use within an opening defined in a component, wherein the opening extends between a first end and a second end. The fastener assembly may generally include a fastener movable within the opening between a retracted position and an attachment position. The fastener may include a body having a shank portion, a threaded portion opposite the shank portion and a recessed portion defined between the shank portion and the threaded portion. The fastener assembly may also include a retention member configured to be positioned within the opening adjacent the recessed portion such that the retention member engages at least one of the shank portion or the threaded portion as the fastener is moved between the retracted position and the attachment position. In addition, the fastener assembly may include a biasing member engaged against the retention member. The biasing member may be configured to bias the fastener towards the retracted position, wherein the threaded portion is at least partially refracted within the opening when the fastener is in the retracted position.
These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents.
In general, the present subject matter is directed to a fastener assembly for coupling a transition piece within a gas turbine. Specifically, in several embodiments, the fastener assembly may include a fastener configured to be coupled between a bracket of the transition piece and another portion of the gas turbine, such as a retaining ring of the gas turbine. For example, the transition piece bracket may define an opening through which the fastener may be inserted and screwed into a corresponding opening defined in the retaining ring. Additionally, in one embodiment, the fastener assembly may include a retention member configured to retain the fastener within the bracket opening, thereby preventing the fastener from falling into the gas turbine as the transition piece is being installed and/or removed. For example, the retention member may be configured to engage portions of the fastener within the opening, thereby restricting the movement of the fastener relative to the bracket. Additionally, in several embodiments, the fastener assembly may include a biasing member configured to retract a portion of the fastener within the opening, thereby protecting the fastener from damage as the transition piece is being installed and/or removed.
Referring now to the drawings,
As shown, the combustor 12 may generally include an internal flow sleeve 18 and a combustion liner 20 substantially concentrically arranged within the flow sleeve 18. The combustion liner 20 may generally define a substantially cylindrical combustion chamber 22, wherein fuel and air are injected and combusted to produce hot gases of combustion. Additionally, both the flow sleeve 18 and the combustion liner 20 may extend, at their downstream ends, to a double walled transition piece 14, including an impingement sleeve 24 and an transition duct 26 disposed radially inwardly from the impingement sleeve 24. In particular, the combustion liner 20 may be coupled at its downstream end to the transition duct 26 such that the combustion liner 20 and the transition duct 26 generally define a flowpath for the hot gases of combustion flowing from the combustor 12 to a first stage nozzle 28 of the gas turbine 10. Moreover, the flow sleeve 18 may be coupled at its downstream end to the impingement sleeve 24 such that the flow sleeve 18 and the impingement sleeve 24 generally define a flowpath for the pressurized air discharged from a compressor (not shown) of the gas turbine 10. For example, the impingement sleeve 24 may define a plurality of cooling holes 30 configured to permit the pressurized air to enter the radial space defined between the transition duct 26 and the impingement sleeve 24. The pressurized air may then flow between the combustion liner 20 and the flow sleeve 18 to an end cap (not shown) of the combustor 12, wherein the air is mixed with fuel and injected into the combustion chamber 22.
As shown in
Additionally, the aft frame 32 may be configured to be coupled to the annular retaining ring 16 of the gas turbine 10. In general, the aft frame 32 may be coupled to the retaining ring 16 using any suitable attachment means and/or method known in the art. For example, in several embodiments, the aft frame 32 may include suitable mounting structure, such as one or more support handles 42, configured to be coupled to the retaining ring 16 via a transition piece bracket 44. Specifically, as shown in
Moreover, as shown in the illustrated embodiment, the transition piece bracket 44 may be configured to extend axially from the support handle(s) 42 towards the retaining ring 16. For example, as particularly shown in
It should be appreciated that the transition piece bracket 44 may generally define any suitable shape and/or have any suitable configuration that permits it to function as described herein. For example, as shown in
It should also be appreciated that, although the transition piece bracket 44 is generally described herein with respect to coupling the aft frame 32 to the retaining ring 16, the bracket 44 may generally be utilized to couple the aft frame 32 to any suitable component of the gas turbine 10. For example, the bracket 44 may be configured to be coupled between the aft frame 32 and a portion of the turbine casing (not shown) of the gas turbine 10 or between the aft frame 32 and any other suitable component of the gas turbine 10.
Referring now to
As shown, the fastener assembly 100 may generally include a fastener 102 (e.g., a bolt or any other suitable mechanical fastener) configured to be received within an opening 104 defined in the transition piece bracket 44. In general, the fastener 102 may include a head 106 and a body 108 extending from the head 106 along a longitudinal axis 110 (
It should be appreciated that, in several embodiments, the head 106 of the fastener 102 may be configured to indirectly engage the outer surface 112 of the transition piece bracket 44. For example, as shown in the illustrated embodiment, a washer 120 may be installed on the fastener 102 such that the head 106 engages the outer surface 112 indirectly (via the washer 120) when the fastener 102 is moved to the attachment position. However, in other embodiments, the head 106 of the fastener 102 may be configured to directly engage the outer surface 112 of the transition piece bracket 44 (e.g., by removing the washer 120) when the fastener 102 is moved to the attachment position.
Additionally, as shown in the illustrated embodiment, the body 108 of the fastener 102 may generally include a shank portion 122 extending from the head 106, a threaded portion 124 opposite the shank portion 122 and a recessed portion 126 defined between the shank portion 122 and the threaded portion 124. In several embodiments, the threaded portion 124 may be configured to be secured within a corresponding threaded opening 128 (
As shown in
Moreover, as shown in the illustrated embodiment, the fastener assembly 100 may also include a retention member 138 configured to be positioned within the opening 104 at a location adjacent to the recessed position 126. Specifically, the retention member 138 may generally be configured to define an inner cross-sectional width 140 (
It should be appreciated that the retention member 138 may generally comprise any suitable object and/or feature that is configured to function as described herein. For example, as particularly shown in
Additionally, the fastener assembly 100 may also include a collar 144 configured to support the retention member 138 within the opening 104. Specifically, in several embodiments, the collar 144 may comprise a hollow, cylindrically-shaped body configured to be inserted and/or secured within the second end 118 of the opening 104. For instance, as shown in
It should be appreciated that the collar 144 may be secured within the opening 104 using any suitable means known in the art. For example, as shown in the illustrated embodiment, the collar 144 may define a threaded end 148 configured to be secured within a corresponding threaded section 150 (
Referring particularly to
It should be appreciated that, although the biasing member 142 is illustrated herein as being a spring, the biasing member 142 may generally comprise any suitable object that is capable of preforming the functions described herein. For example, in an alternative embodiment, the biasing member 142 may simply comprise a mass of elastic material capable of applying a suitable spring force against the fastener 102 in order to move the fastener 102 to the retracted position in the absence of opposing forces.
Additionally, it should be appreciated that, in several embodiments, the present subject matter may also be directed to a method for installing the fastener assembly 100 within the opening 104. Specifically, in one embodiment, the fastener 102 (optionally including the washer 120 installed thereon) may be initially inserted into the first end 116 of the opening 104 until the head 106 engages the outer surface 112 of the transition piece bracket 44. The biasing member 142 may then be installed on the fastener 102, such as by positioning the biasing 142 onto the threaded portion 124 and pushing the biasing member 142 into the opening 104 along the length of the body 108. The retention member 138 may then be installed on and/or around the recessed portion 126. For example, as shown in
Referring now to
It should be appreciated that, although the disclosed fastener assembly 100 has been described herein with reference to coupling a transition piece bracket 44 to a retaining ring 16 of a gas turbine 10, the fastener assembly 100 may generally be utilized to couple any two components together, particularly when it is desirable to retain the fastener 102 within an opening defined in one of the components and/or when it is desirable to retract a portion of the fastener 102 within the opening. Thus, it should be readily understood that the opening 104 described herein may generally be defined in any suitable component.
This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.