Patent Application
20170009658
The present invention generally involves an exhaust gas system. More particularly, the invention relates to an insulation support system for an exhaust gas system.
A gas turbine generally includes, in serial flow order, an inlet system, a compressor, a combustion section and a turbine. Various exhaust gas related components may be disposed downstream from an outlet of the turbine including but not limited to an exhaust gas diffuser, exhaust plenum, a bypass stack, a diverter damper, a heat recovery steam generator (HRSG), etc . . . . The exhaust gas diffuser defines a flow path for routing relatively hot combustion gases away from the turbine. The hot combustion gases may then be routed through the various outer exhaust gas related components.
The exhaust gas diffuser is typically formed by an outer casing or shell and multiple liner sheets that are coupled to an inner surface of the outer casing and that define an outer flow boundary of the flow path. In order to reduce the temperature of the outer casing, insulation, usually in the form of fiber batts, is packed between the inner surface of the outer casing and an inner surface of each liner sheet.
The liner sheets are installed with welded studs that have nuts to clamp down the individual liner sheets. These nuts need to be torqued to a specific value, and then backed off to allow the liner sheet to float in order to allow for varying thermal growth rates of the liner sheets and/or the outer casing. The nuts are tack welded in place to prevent them from backing off. The liner sheets, the welded studs, nuts and liner sheets define an insulation support system
In order to ensure proper installation of the liner sheets and insulation using known insulation support systems as described above, a calibrated torque wrench, skilled labor and a high level of Quality Control are required. Improperly installed nuts that are too tight may restrict the relative movement of the liner sheets, thus potentially resulting in liner sheet buckling. Improperly installed nuts that are too loose may also allow the liner sheets to rattle, thus potentially compressing and decompressing the insulation which may compromise the thermal insulating value of the insulation. Therefore an improved insulation support system would be useful.
Aspects and advantages of the invention are set forth below in the following description, or may be obvious from the description, or may be learned through practice of the invention.
One embodiment of the present invention is an insulation support system for a gas turbine. The insulation support system includes an outer casing having an inner surface and a liner sheet having an inner surface and defining a fastener hole. An insulation gap is defined between the inner surface of the liner sheet and the inner surface of the outer casing. The system further includes a support member that extends from the inner surface of the outer casing to the inner surface of the liner sheet. A threaded fastener is fixedly connected to one of inner surface of the outer casing or the support member and has a fixed depth. The threaded fastener is substantially aligned with the fastener hole of the liner sheet. The system further includes a bolt that extends through the bolt hole of the liner sheet and that threadingly engages with the threaded fastener.
The present invention also includes a gas turbine. The gas turbine includes a compressor, a combustion section disposed downstream from the compressor, a turbine disposed downstream from the combustion section and an exhaust section disposed downstream from the turbine. The exhaust section includes an insulation support system. The insulation support system includes an outer casing having an inner surface and a liner sheet having an inner surface and that defines a fastener hole. An insulation gap is defined between the inner surface of the liner sheet and the inner surface of the outer casing. The system further includes a support member that extends from the inner surface of the outer casing to the inner surface of the liner sheet and a threaded fastener that is fixedly connected to one of inner surface of the outer casing or the support member. The threaded fastener has a fixed depth and is aligned with the fastener hole of the liner sheet. The system also includes a bolt that extends through the bolt hole of the liner sheet and threadingly engages with the threaded fastener.
Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the specification.
A full and enabling disclosure of the present invention, including the best mode thereof to one skilled in the art, is set forth more particularly in the remainder of the specification, including reference to the accompanying figures, in which:
Reference will now be made in detail to present embodiments of the invention, one or more examples of which are illustrated in the accompanying drawings. The detailed description uses numerical and letter designations to refer to features in the drawings. Like or similar designations in the drawings and description have been used to refer to like or similar parts of the invention. As used herein, the terms “first”, “second”, and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, and the term “axially” refers to the relative direction that is substantially parallel to an axial centerline of a particular component.
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 modifications and variations can be made in the present invention without departing from the scope or spirit thereof. For instance, features illustrated or described as part of one embodiment may be used on 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. Although exemplary embodiments of the present invention will be described generally in the context of a liner support system for an exhaust diffuser for a land based power generating gas turbine for purposes of illustration, one of ordinary skill in the art will readily appreciate that embodiments of the present invention may be applied to any type of exhaust gas enclosure or exhaust gas related component such as but not limited to an exhaust gas plenum, a bypass stack, a diverter damper, a heat recovery steam generator (HRSG) and/or a waste heat recovery unit (WHRU). In addition, the exhaust gas enclosure may be associated with any turbomachine type such as a steam turbine, a marine gas turbine or aircraft gas turbine and is not limited to land based power generating gas turbines unless specifically recited in the claims.
Referring now to the drawings, wherein identical numerals indicate the same elements throughout the figures,
The compressed air 18 is mixed with a fuel 20 from a fuel supply system 22 to form a combustible mixture within one or more combustors 24. The combustible mixture is burned to produce combustion gases 26 having a high temperature, pressure and velocity. The combustion gases 26 flow through a turbine 28 of a turbine section to produce work. For example, the turbine 28 may be connected to a shaft 30 so that rotation of the turbine 28 drives the compressor 16 to produce the compressed air 18. Alternately or in addition, the shaft 30 may connect the turbine 28 to a generator (not shown) for producing electricity. Exhaust gases 32 from the turbine 28 flow through an exhaust section 34 that connects the turbine 28 to an exhaust stack 36 downstream from the turbine 28. The exhaust section 34 may include various components, for example, an exhaust diffuser and a heat recovery steam generator (not shown) for cleaning and extracting additional heat from the exhaust gases 32 prior to release to the environment.
A plurality of groups of axially extending support members 44, 46, 48 are arranged in parallel, in the longitudinal direction of the outer casing 40 and may be welded or otherwise fixedly connected to an interior surface 50 of the outer casing. The length of the support members 44, 46, 48 vary depending on their axial location within the exhaust diffuser 38. One or more of the support members 44, 46, 48 may include one or more threaded studs 52. Forward, transverse support members 54, 56 may be provided at the forward end of the outer casing 40. Insulation 58, preferably in the form of fiber batts (only one shown at 58 for simplicity sake), is installed between the support members 44, 46 and 48 along the length of the outer casing 40. The insulation 58 protects the carbon steel outer casing 40 from exhaust gas temperatures which may exceed 1400 degrees F. In other embodiments, the studs 52 may be welded directly to the casing 40.
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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 language of the claims.
