Patent Application
20120282083
The subject matter disclosed herein relates to a turbine casing. Specifically, the subject matter disclosed herein relates to a steam turbine casing including a ledge ring partition aperture (or, cutout), allowing for a flush interface between an extraction conduit and a ledge ring.
Conventional turbine casing segments (e.g., in low-pressure, or LP, steam turbine casing segments) include built-up interfaces, commonly referred to as extraction boxes, for connecting extraction conduits to the casing segment. Typically, each extraction conduit has a wider diameter than the axial length of its respective turbine stage. The extraction box provides an interface between the wider extraction conduit and the narrower turbine stage casing segment, such that a desired amount of working fluid (e.g., steam) may be extracted from the desired stage of the turbine.
In some turbine applications, incorporating extraction boxes into the turbine casing may be impracticable. For example, in some cases, extraction boxes may occupy an undesirable amount of space in the casing segment, and may complicate the fabrication of the casing segment.
A turbine casing segment is disclosed. In one embodiment, a turbine casing segment is disclosed including: a plurality of stage segments; a plurality of ledge ring partitions separating the plurality of stage segments, wherein at least one of the plurality of ledge ring partitions has an axially extending aperture therethrough; and a substantially rounded extraction aperture located flush with an inner surface of one of the plurality of stage segments.
A first aspect of the invention includes a turbine casing having a plurality of stage segments; a plurality of ledge ring partitions separating the plurality of stage segments, wherein at least one of the plurality of ledge ring partitions has an axially extending aperture therethrough; and a substantially rounded extraction aperture located flush with an inner surface of one of the plurality of stage segments.
A second aspect of the invention includes a turbine casing segment having: a plurality of stage segments; a plurality of ledge ring partitions separating the plurality of stage segments, wherein a first one of the plurality of ledge ring partitions has an axially extending aperture therethrough; an extraction aperture fluidly connected with an inner surface of one of the plurality of stage segments proximate to the axially extending aperture; and an extraction conduit fluidly connected with the extraction aperture, wherein the extraction conduit and the extraction aperture share a substantially identical inner diameter throughout a length of the extraction conduit.
A third aspect of the invention includes a turbine casing having: an upper casing segment; and a lower casing segment coupled to the upper casing segment, the lower casing segment including: a plurality of ledge ring partitions defining a plurality of stage segments, wherein at least two of the plurality of ledge ring partitions define portions of a first stage segment radially inboard of an adjacent second stage segment; and an extraction aperture located flush with an inner surface of one of the first stage segment or the second stage segment.
These and other features of this invention will be more readily understood from the following detailed description of the various aspects of the invention taken in conjunction with the accompanying drawings that depict various embodiments of the invention, in which:
It is noted that the drawings of the invention are not necessarily to scale. The drawings are intended to depict only typical aspects of the invention, and therefore should not be considered as limiting the scope of the invention. In the drawings, like numbering represents like elements between the drawings.
Aspects of the invention provide for a turbine casing segment, e.g., a steam turbine casing segment including ledge ring partition aperture (or, cutout), allowing for a flush (or continuous, or uninterrupted) interface with an extraction conduit. One particular aspect of the invention provides for a turbine casing segment having an extraction aperture and a corresponding extraction conduit, each with substantially identical inner diameters.
As noted herein, conventional turbine casing segments (e.g., in low-pressure, or LP, steam turbine casing segments) include built-up interfaces, commonly referred to as extraction boxes, for connecting extraction conduits to the casing segment. These extraction boxes have distinct inner dimensions (e.g., length and width) from the extraction conduits to which they are connected. In some turbine applications, incorporating extraction boxes into the turbine casing may be impracticable. For example, in some cases, extraction boxes may occupy an undesirable amount of space in the casing segment, and may complicate the fabrication of the casing segment. Additionally, in some designs, it is desirable to integrate additional extraction conduits, and the use of extraction boxes may violate spacing constraints in such designs.
In one aspect of the invention, a turbine casing segment is disclosed. This turbine casing segment can include: a plurality of stage segments; a plurality of ledge ring partitions separating the plurality of stage segments, wherein at least one of the plurality of ledge ring partitions has an axially extending aperture therethrough; and a substantially rounded extraction aperture located flush with an inner surface of one of the plurality of stage segments. In a second aspect of the invention, a turbine casing segment is disclosed, including: a plurality of stage segments; a plurality of ledge ring partitions separating the plurality of stage segments, wherein a first one of the plurality of ledge ring partitions has an axially extending aperture therethrough; an extraction aperture fluidly connected with an inner surface of one of the plurality of stage segments proximate to the axially extending aperture; and an extraction conduit fluidly connected with the extraction aperture, wherein the extraction conduit and the extraction aperture share a substantially identical inner diameter throughout a length of the extraction conduit.
A third aspect of the invention includes a turbine casing having: an upper casing segment; and a lower casing segment coupled to the upper casing segment, the lower casing segment including: a plurality of ledge ring partitions defining a plurality of stage segments, wherein at least two of the plurality of ledge ring partitions define portions of a first stage segment radially inboard of an adjacent second stage segment; and an extraction aperture located flush with an inner surface of one of the first stage segment or the second stage segment. In this embodiment, ledge ring partitions may define a distinct fluid channel, radially inboard of the casing inner surface (or, wall).
In contrast to conventional turbine casing segments, which employ extraction boxes, aspects of the invention provide for turbine casing segments having an extraction aperture located flush with an inner surface of one of the turbine stage segments. This extraction aperture may be a continuous extension of an extraction conduit configured to extract a working fluid (e.g., steam) from the turbine casing. One aspect of the invention allowing for these flush extraction apertures (and corresponding conduits) is the implementation of ledge ring partitions (or, stage partitions) having apertures, or cutouts extending axially therethrough. These cutouts allow for the placement of extraction apertures flush against the inner surface of the turbine casing and spanning axially between two of the turbine stages.
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In any case, it is understood that aspects of the invention provide for ledge ring partitions 10 having apertures, or cutouts, 11, which allow for extraction conduits 16 that directly contact the inner surface of the turbine stage segments (e.g., the inner surface 14 of lower casing segment 6). Due to the design of the ledge ring partitions, additional extraction conduits (and extraction apertures) may be integrated into the design of the lower casing segment (as compared to the conventional designs), such that a desired amount of steam may be extracted from the lower casing segment without the use of extraction “boxes.” It is understood that conventionally, casing segments may be fabricated (e.g., by fabricating from one or more pieces of material such as a metal), and that reducing the complexity of that fabrication process may improve the end-product yield, and reduce costs. As compared with the conventional extraction box configuration, aspects of the invention may reduce the complexity of fabricating turbine casing segments (e.g., turbine casing segment 6). For example, aspects of the invention may reduce the complexity of fabricating a turbine casing segment (e.g., turbine casing segment 6) because the extraction conduit and extraction aperture have substantially identical inner diameters (thereby eliminating an interface step, or ledge). Additionally, without the additional fabricating required for an extraction “box” (as in conventional casing segments), fabricating of the turbine casing segment 6 disclosed herein may reduce costs and complexity. Even further, additional steam may be extracted from the turbine casing segment 6 employing extraction apertures 12 and conduits 16 that can span axially between more than one casing segment 8.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
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 have 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.
