This invention relates generally to the field of gas combustion turbines, and more particularly to tubing assemblies that supply forced air or steam coolant to transition pieces of a gas turbine.
Gas turbines are well known in the art of power generation. A gas turbine comprises a compressor section where air is pressurized. This air then flows to a plurality of radially arranged combustion chambers in which fuel is combusted to form a hot combustion gas. The hot gas passes through a transition piece into a first stage of a turbine where the enthalpy of the gas is converted into mechanical energy. It is noted that transition piece alternatively is referred to as a “tail pipe” or “transition duct” by some in the field. Prior art references that are hereby incorporated by reference, particularly for the teachings of the structure of transition pieces and for the sources of stresses thereto, are: U.S. Pat. No. 4,422,288 to Steber, issued Dec. 27, 1983; U.S. Pat. No. 5,906,093 to Coslow et al., issued May 25, 1999; U.S. Pat. No. 6,463,742 B2 to Mandai et al., issued Oct. 15, 2002; and U.S. Pat. No. 6,662,568 B2 to Shimizu et al., issued Dec. 16, 2003. Also of interest is U.S. Pat. No. 6,523,352 B1, to Takahashi et al., issued Feb. 25, 2003, incorporated by reference in its entirety.
The transition piece receives hot combustion gases. As such the transition piece and components attached thereto are subject to stress from high temperatures, vibrations, and extreme temperature gradients over long periods of operation. Some gas turbine transition pieces are cooled by forcing air over the outside of the units while other transition pieces contain cooling channels through which forced air or steam flow to cool the transition pieces. The latter types are known generally as forced-cooled transition pieces.
Forced-cooled transition pieces include steam-cooled transition pieces in which steam is supplied to the transition piece via intake (i.e., supply) tubing and in which separate exhaust tubing returns the hotter steam from the transition pieces back to a steam system. For example, one set of steam-cooling operational parameters for cooling a transition piece include: inlet (i.e., supply) steam around 500 degrees Fahrenheit (“° F.”) inlet pressure around 260 pounds per square inch (“psi”) and outlet or exhaust steam temperature around 1000° F.
Prior art piping or tubing assemblies that connect forced cooling fluid supply and return systems to a transition piece are comprised of rigid pipe that is welded at each bend. Forced air and steam are the common force-cooled fluids, and a unitary manifold is a common structure to convey supply side and return side fluids. An example of a prior art welded tubing assembly that transports steam is shown in
Construction of such welded rigid pipe assemblies requires substantial labor. Also, if the fit between manifold and port is not accurate, and/or if there is improper handling during shipping or installation, static loading may be imposed on the tubing assembly that shortens its useful life.
Temperature stresses may arise from the sustained high temperature on a component of the tubing assembly, from exposure to a high temperature gradient along a length of material, or from both. In addition to temperature stresses the transition piece and the tubing assemblies associated with it are subject to vibrations, such as from the varying nature of the combustion, and from related vibrations transferred from the manifold. As noted above, certain stress might accrue from undesirable static loading on the assembly such as when improper handling, by the supplier and/or due to improper installation, strain one or more of the tubing assemblies or their components. As the tubing assemblies or their components having such static loading are then brought up to operational temperature, and remain there for extended operating periods, additional stress from the initial static loading can contribute to the other stresses.
For the figures described herein, unless otherwise indicated like reference numerals refer to the same or similar structures identified in previous figures. Also, as used in the specification and claims, the terms “inlet,” “intake” and “supply” are taken to indicate the same with regard to a tubing assembly, and “outlet,” “return,” and “exhaust” likewise are taken to indicate the same with regard to a tubing assembly.
Also, the terms “replaceable” and “removable” are taken to mean the same thing when referring to tubing assembly components that fluidly communicate with the cooling system in a transition piece. Owing to its removability and ease of replacement, such tubing assembly sections are also termed “field-installable.” The term “field-installable” also applies to certain combinations of the present invention that comprise a transition piece and one or more components of the tubing assembly, such as the replaceable sections for the intake and outlet sides of the forced cooling system. As is disclosed herein, such field-installable combinations provide for ready installation and/or replacement of worn units without a need for extensive welding in situ, and avoids the installation of transition pieces having extensive pre-welded cooling system tubing assemblies. Thus, the terms “replaceable,” “removable” and “field-installable” as applied to these components and assemblies indicates that these are more readily and more easily installed or changed out than known components and assemblies.
One embodiment of the present invention is a flexible tubing assembly for conducting a fluid for forced cooling of a transition piece of a gas turbine where that assembly comprises an inline flexible connector. Another embodiment of the present invention is a removable flexible tubing assembly for conducting a fluid for forced cooling of a transition piece of a gas turbine the assembly being with or without the inline flexible connector. Another embodiment of the present invention is a forced cooling transition assembly in which the transition piece comprises heat transfer channels ending in inlet and outlet chambers and further comprising a tubing assembly connecting to the inlet and outlet chambers that advantageously transfers certain loads to the transition piece and that further comprises a formed tubing bend and a flexible inline connector. Combinations are disclosed that include a transition piece together with a tubing assembly. Specific embodiments of the present invention are described below making reference to figures attached hereto.
While it is recognized that a manifold is most typically used to supply fluid for forced cooling of transition pieces, this component is more generally referred to as a “forced cooling fluid supply.” A forced cooling fluid supply, as used herein, including the claims, is taken to include an apparatuses, such as the manifolds depicted in the figures, that has both delivery and return conduits. A forced cooling fluid supply also is taken to mean an apparatus that separately provides a delivery or a return conduit, so that one such apparatus comprises a supply (i.e., delivery) side, and a second such apparatus comprises a return (i.e., outlet) side with respect communicating cooling fluid with the transition piece.
As seen in
To distinguish from the inlet end 12 and aft end 13, which are for combustion gases, an inlet chamber, such as inlet chamber 14, also is identified as a “cooling inlet chamber,” and an outlet chamber, such as outlet chamber 17, also is identified as a “cooling outlet chamber.”
While not necessarily true for all embodiments of the present invention, the herein described components of the inlet tubing assembly 21 and an outlet tubing assembly 22 are shown as having the same or similar components and relationships there between. Accordingly, discussion of component characteristics of the supply side assembly applies as appropriately to the outlet tubing assembly 22. Where convenient, part identification for similar parts of the respective assemblies are distinguished by the suffix “-I” for inlet tubing assembly components, and by “-O” for outlet tubing assembly components. When no suffix is used for such components, the discussion about such component may apply to either or both of the inlet tubing assembly 21 and an outlet tubing assembly 22. This identification system does not apply to the structures to which the respective assemblies attach at their respective ends, nor to the removable unions as described herein.
Also, it is noted that, depending upon design criteria for a particular transition piece, the design and layout of an inlet tubing assembly may differ substantially from the design and layout of an outlet tubing assembly, and still be within the scope of the present invention. For example, referring to
The inlet tubing assembly 21 receives steam from a steam supply source, shown in
A V-band clamp is one type of removable union 52 that is used in embodiments such as those depicted in
The assemblage of components that comprise the tubing assembly between the two removable unions 52 (either for the inlet or the outlet assemblies) collectively is referred to as a “removable tubing section.” The following describes components of one such assemblage, of an inlet tubing assembly 21 as depicted in
Downstream of the flexible coupling 56-I is a bracing member 58-l having a bore passing through it, to fluidly communicate the cooling fluid to adjacent components, and comprising an integral lateral plate 60-I. The lateral plate 60-I has a hole 61 (behind bolt head 63 in
In general, a bracing member is designed to react out plug loads rather than tubing or other components that are positioned farther away from the source of the plug load force. Because the bracing member 58-I transfers load and is under stress during the operation of the gas turbine it is fabricated to withstand such stress. For example, without being limited, this component may be made by casting, by forging, by machining stock material (which in some embodiments includes the lateral plate 60-I), or by welding together a subassembly comprising rigid pipe or a pipe fitting and the lateral plate. In
Downstream of the bracing member 58-I is a formed tubing bend 64-I, here formed to comprise a U-shaped bend of the inlet tubing assembly 21. This formed tubing bend 64-I has a reduced stiffness compared to standard pipe of comparable size (i.e., 1.75 inch outside diameter tubing size compared to 1.5 inch nominal pipe diameter), where that pipe forms a similar bend with welded fittings. By standard pipe is meant the iron pipe normally used to supply transition piece assemblies with a forced cooling fluid. Standard pipe sizing has been used in the past to supply transition piece assemblies with a forced cooling fluid. To develop proper sizing and other specifications for a formed tubing bend as used herein, one skilled in the art may utilize, for instance, finite element modeling software programs, inputting data relevant to a particular turbine and transition piece. As to the specific example depicted in the
In the embodiment depicted in
As depicted in
As noted above the component structures of the outlet tubing assembly 22 may essentially the same as for the above-described inlet tubing assembly 21. However as shown in
Whereas the inlet tubing assembly 21 is definable as the entire section of tubing between the steam manifold 3 and the inlet chamber 14, the readily removable part of the inlet tubing assembly 21 is a replaceable section, 25 (alternately referred to as a “removable tubing section”) which is comprised of the components between ends 54-I and 70-I (see
As described above for the embodiment in
Further as to a bracing member and how to transfer load from it to the transition piece, the above-described lateral plate 60 is but one of a number of alternatives for a support structure that is integral with or appended to the bracing member. The purpose of such support structure is to transfer loads to the transition piece at a point along the length of the tubing section. The point at which such load is transferred generally is identified by the presence of a load-receiving member that may be integral with or attached to the transition piece. The axial stop backing plate 18, discussed above, is but one example of a load-receiving member. The transferring of load to the transition piece serves to isolate a component of the tubing assembly on one side of the support structure from loads generated on the other side. Depending on the shapes and arrangement of elements, and how they contact or are attached to one another, only axial loads may be transferred, loads from all three dimensions may be transferred, or other combinations of moments and/or forces may be transferred. For example, a support structure may be in the form of a plate as shown in
The shapes of a particular support structure and the shapes of the load-receiving member may vary depending on a number of factors, particularly the desired axes, the anticipated loads, and specified tolerances. For example, not to be limiting, the support structure may be a cylindrical rod having a hole drilled through it, and through this hole passes a pin that extends from a plate affixed to the transition piece. Here, the pin and plate comprise the load-receiving member. Alternatively, a plate or bolt may extend from one side of the bracing member with its end positioned into a groove in the transition piece, where the travel in the groove is limited at one end that serves as an axial stop. Here, the groove, including its side and end walls, comprises the load-receiving member. Alternatively, the support structure may be a groove on the bracing member flanked by two spaced apart ridges, where a yoke extending from the transition piece is positioned between the ridges. Then, upon axial movement the tubing is stopped when the yoke meets one of the ridges. Here, the yoke is the load-receiving member. These and any other mechanical designs for associating the bracing member to the transition piece, for the purpose of providing axial or other force transfer, as known to those of ordinary skill in the art, may be used to adapt such components to transfer loads in order to practice this aspect of the invention. It also is noted that the design may include more than load-receiving member on a transition piece, for example, not to be limiting, a first load-receiving member (such as a backing plate) for contact with the inlet tubing assembly 21, and a second load-receiving member (such as a backing plate) for contact with the outlet tubing assembly 22.
It is appreciated that another aspect of the invention is any one of the tubing assemblies disclosed and described above in combination with the transition piece that is connected thereto. For example, and not to be limiting, the transition piece 5 in
Also, it is noted that in other embodiments certain components of the assemblies disclosed above may be eliminated without detracting from the invention. Without being limiting, one example of such component reduction is shown in
Although the examples disclosed herein are comprised of removable unions at both sides of tubing assemblies, it is noted that other embodiments of the present invention have an inlet or an outlet tubing assembly comprised of a bracing zone (such as bracing member 58-I in
Thus, by virtue of the examples and discussion herein, it is appreciated that one aspect of the present invention is the realization that a way to solve the problems identified in tubing assemblies to transition pieces that provide force-cooling is to provide both a bracing zone and a formed tubing zone. That is, considering only one of the inlet or the outlet tubing assemblies, there is a bracing zone that transfers loads from the tubing assembly to a point on the transition piece (i.e., via the lateral plate 60 of the bracing member 58). And there also is a formed tubing zone comprised of formed tubing that is less rigid than comparable pipe with welded fittings (i.e., the U-shaped formed tubing bend 64). These two zones, in contrast to the tubing assemblies in the art, have compositions imparting different levels of rigidity, and thus may be considered heterogeneous. Such embodiments of the present invention are considered “dual-zone” assemblies. Advantageously in examples provided herein, the formed tubing zone may include a U-shaped bend that is important in redirecting the flow of force-cooling fluid 180 degrees, as is done to comport with standard designs of gas turbines.
Additionally, embodiments may also include a third zone comprising a flexible coupling. This zone, a flexibility zone, is positioned between the bracing zone and the manifold, and is characterized by such coupling's ability to lessen the loads and consequent stress and wear on other components due to its flexibility. More particularly, for instance (not to be limiting), a flexibility zone comprising a flexible coupling provides axial and lateral flexibility. Accordingly, and more generally, the embodiments of the present invention are considered to be comprised of multi-zone tubing assemblies that supply forced-cooled fluids to a transition piece of a gas turbine engine.
It also is appreciated that the term “pipe,” as used herein to describe the parts emanating from the force-cooled fluid supply (i.e., manifold), and the inlet and outlet chambers of the transition piece, which fluidly connect with the removable sections described herein, may include any type of structure or assembly that fluidly transmits the force-cooled fluid in place of the sections of pipe described and illustrated herein. For instance, not to be limiting, a molded transition piece inlet assembly may have a structure to connect to the removable sections described herein which does not literally have a separate piece of pipe welded thereto. Such structure, which may alternately be identified as an “extended port,” is considered to fall within the scope of the functional definition of a “pipe” as used herein.
Further, in view of the advantages of the assemblies described above, including assemblies that are comprised of a transitional piece and two replaceable sections of force-cooling tubing (as depicted in
It is appreciated that the above steps 1–3, and variations of these as are known in the art, more generally is described as “installing a transition piece to join a combustor and turbine first stage.”
Alternatively, it is appreciated that in other instances, a field-installable transition piece assembly 10, comprising a transition piece 5 assembled in combination with the inlet tubing assembly 21 and the outlet tubing assembly 22, may be installed as a single unit.
Further, is it appreciated that another aspect of the present invention is the method of installing either the inlet (supply) or the outlet (return) replaceable tubing sections onto a transition piece, whether on a new transition piece or during replacement of an old tubing assembly on a transition piece installed in a turbine. More particularly, such method for field-installing a supply section comprises:
In the methods described above, it is appreciated that, where there is a flexibility zone comprising a flexible coupling at one end, and a formed tubing zone comprising a formed tubing bend at the other end, with a bracing zone between, the flexibility at each end aids in the fitting in of the respective end to the respective adjoining mating pipe. This occurs both whether or not the bracing zone has first been attached to the transition piece via its support structure. That is, even when the bracing member is secured via its support structure to the transition piece load-receiving member, the flexibility at each end provides for an easier fit-up, with removable or other connectors, to the respective end of the respective adjoining mating pipe.
It should be understood that the examples and embodiments described herein are for illustrative purposes only and that various modifications or changes in light thereof will be suggested to persons skilled in the art and are to be included within the spirit and purview of this application and the scope of the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
4422288 | Steber | Dec 1983 | A |
4819438 | Schultz | Apr 1989 | A |
5819525 | Gaul et al. | Oct 1998 | A |
5906093 | Coslow et al. | May 1999 | A |
6173561 | Sato et al. | Jan 2001 | B1 |
6463742 | Mandai et al. | Oct 2002 | B2 |
6523352 | Takahashi et al. | Feb 2003 | B1 |
6553766 | Shimizu et al. | Apr 2003 | B2 |
6662568 | Shimizu et al. | Dec 2003 | B2 |
6890148 | Nordlund | May 2005 | B2 |
20030167776 | Coppola | Sep 2003 | A1 |
Number | Date | Country |
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0 926 324 | Jun 1999 | EP |
Number | Date | Country | |
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20050279099 A1 | Dec 2005 | US |