Patent Publication Number: US-8523518-B2

Title: Systems, methods, and apparatus for linking machine stators

Description:
FIELD OF THE INVENTION 
     This invention generally relates to machines and more specifically, to linking or joining machine stators. 
     BACKGROUND OF THE INVENTION 
     Machines, such as turbines, are used in a wide variety of aviation, industrial and power generation applications. Typically, turbine components, such as a compressor or a turbine section of a gas turbine, include a plurality of rotating blades extending from a rotor and a plurality of stationary blades, or stators, extending from a stationary component of the turbine, such as the casing of the turbine. The stators typically extend between the rotating blades of a turbine component. In operation, the stators are typically loaded and unloaded during starting and stopping of the turbine. Additionally, the stators are often subject to small pressure fluctuations during operation. As a result, relative motion or stator rocking may result between the bases of the stators and the casing of the turbine, leading to a flow path within the turbine component that is different than the intended design. This can lead to wear on both the stators and the casing. Additionally, the stator rocking can lead to decreased efficiency, and therefore, decreased power output of a turbine. 
     Attempts have been made to reduce stator rocking by connecting stators together. One solution involves inserting a pin in the base of a first stator that extends into the base of an adjacent stator. Although the connection of stators with pins reduces stator rocking, given the curvature of the turbine casing, stators connected in this manner often have a gap between their bases. These gaps can lead to losses within the turbine component as a portion of the flow path is diverted between adjoining stator bases. 
     Accordingly, there is a need for improved systems, methods, and apparatus for linking, joining, or connecting machine stators. 
     BRIEF DESCRIPTION OF THE INVENTION 
     According to one embodiment of the invention, there is disclosed a bracket for linking stators in a machine. The bracket may include a body portion, a first plurality of extensions, and a second plurality of extensions. The body portion may include a first edge operable to align with a base of a first stator and a second edge opposite the first edge and operable to align with a base of a second stator. The first plurality of extensions may extend from the first edge and may be operable to align with at least one corresponding groove on the base of the first stator. The second plurality of extensions may extend from the second edge and may be operable to align with at least one corresponding groove on the base of the second stator. 
     According to another embodiment of the invention, there is disclosed a machine component that may include a casing that surrounds a rotor, a plurality of stators attached to the casing, and a bracket operable to link at least two of the plurality of stators. The brackets may include a body portion, a first plurality of extensions, and a second plurality of extensions. The body portion may include a first edge operable to align with a base of a first stator and a second edge opposite the first edge and operable to align with a base of a second stator. The first plurality of extensions may extend from the first edge and may be operable to align with at least one corresponding groove on the base of the first stator. The second plurality of extensions may extend from the second edge and may be operable to align with at least one corresponding groove on the base of the second stator. 
     According to yet another embodiment of the invention, there is disclosed a method for linking stators in a machine component. Two stator base members operable to support a respective stator blade may be provided, wherein each of the two base members includes one or more grooves. A bracket may also be provided. The bracket may include a body, a first set of extensions that are receivable by the one or more grooves of a first of the two base members, and a second set of extensions that are receivable by the one or more grooves of the other base member. The two base members may be linked with the bracket within the machine component. 
     Other embodiments, aspects, and features of the invention will become apparent to those skilled in the art from the following detailed description, the accompanying drawings, and the appended claims. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein: 
         FIG. 1  is a cross-sectional view of one example of a gas turbine in which embodiments of the invention may be utilized. 
         FIG. 2  is a exploded view of a compressor portion of the gas turbine, within which embodiments of the invention may be utilized. 
         FIG. 3  is a perspective view of one example stator that may be utilized in association with various embodiments of the invention. 
         FIG. 4  is a perspective view of one example bracket that may be utilized to link two stators in a turbine, according to an illustrative embodiment of the invention. 
         FIG. 5  is a perspective view of two stator bases that have been linked by a bracket in accordance with an illustrative embodiment of the invention. 
         FIG. 6  is a flowchart of one example method for linking stators in a machine, according to an illustrative embodiment of the invention. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Illustrative embodiments of the invention now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, the invention may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout. 
     Disclosed are systems, methods, and apparatus for linking stators in a machine, such as, a turbine. A bracket may be provided that facilitates linking two or more stators together. The bracket may include a body portion, a first plurality of extensions, and a second plurality of extensions. The body portion may include a first edge operable to align with a base of a first stator and a second edge opposite the first edge and operable to align with a base of a second stator. The first plurality of extensions may extend from the first edge and may be operable to align with at least one corresponding groove on the base of the first stator. The second plurality of extensions may extend from the second edge and may be operable to align with at least one corresponding groove on the base of the second stator. When utilized to link the first stator and the second stator, the bracket may facilitate a reduction of vibrations in the first stator and the second stator. Additionally, the body portion of the bracket may form a surface between the first stator and the second stator that facilitates a reduction in airflow between the first stator and the second stator. 
     Embodiments of the invention may be utilized in association with a wide variety of different machines. Examples of machines that may incorporate embodiments of the invention include turbines.  FIG. 1  illustrates a cross-sectional view of one example of a gas turbine  100  in which embodiments of the invention may be utilized. Although a gas turbine  100  is illustrated in  FIG. 1 , embodiments of the invention may be utilized in a wide variety of different turbine designs and turbine types including, but not limited to, gas turbines, steam turbines, and other turbines utilized for various aviation, industrial, and/or power generation applications. 
     With reference to  FIG. 1 , the illustrated gas turbine  100  may include an intake section  102 , a compressor section  104 , a combustor section  106 , a turbine section  108 , and an exhaust section  110 . In general operation, air may enter through the intake section  102  and may be compressed to a predefined or predetermined pressure in the compressor section  104 . At least a portion of the compressed air from the compressor section  104  may be supplied to the combustion section  106 . In the combustion section  106 , the compressed air may be mixed with a fuel and then the combined air and fuel mixture may be combusted. The combustion of the air and fuel mixture in the combustion section  106  may produce hot gases having a relatively high temperature and a relatively high pressure. The hot gases coming out of the combustion section  106  may be expanded in the turbine section  108  of the gas turbine  100 . The turbine section  108  may convert the energy of the hot gases to rotation energy. Following the expansion of the hot gases in the turbine section  108 , relatively low pressure hot gases may be sent out from the gas turbine  100  through the exhaust section  110 . The relatively low pressure hot gases coming out from the exhaust section  110  may be sent out to the atmosphere, to a combined cycle regeneration plant, and/or to a recirculation duct of a heat exchanger. 
       FIG. 2  is a cross-sectional view of a compressor section of a turbine, such as a compressor section  104  of the turbine  100  shown in  FIG. 1 . The compressor section  104  may include a rotor  205  that is driven or rotated by a shaft  210 . The shaft may be driven by a power source, such as, the turbine section  108  of the turbine  100 . The rotor  205  may have a plurality of rotor blades, vanes, or buckets  215  attached to it. The plurality of rotor blades  215  may extend from the outer surface of the rotor  205 . Additionally, the plurality of rotor blades  215  may be arranged in rows along the outer surface of the rotor  205 . 
     Interposed between the rows of rotor blades  215  may be stator blades or vanes  220 . The stator blades  220  may also be arranged in rows and the stator blades  220  may be attached to and extend from a stationary component of the compressor section  104 , such as, the housing or casing of the compressor section  104 . For purposes of this disclosure, the various rows of rotor blades  215  and stator blades  220  may be referred to as stages of the compressor section  104 . Additionally, each of the rows of stator blades  220  may be attached to housing or casing by being inserted into a slot associated with a corresponding row or stage of the compressor section  104 . For example, a respective slot, such as slot  222 , may be provided in the casing for each row or stage of stator blades. 
     The housing or casing of the compressor section  104  may include a plurality of components that may be connected to form a casing around the rotor  205  and the rotor blades  215 . As shown in  FIG. 2 , the housing or casing may include a first component  225  and a second component  230  that may be connected to one another around the rotor  205 ; however, the housing or casing may include any number of components as desired in various embodiments of the invention. As shown, the first component  225  and the second component  230  may each be semi-circular portions that are fitted together to encircle the rotor  205 . For example, the first component  225  and the second component  230  may each have an approximately one hundred and eighty degree (180°) curvature. The two components  225 ,  230  may encircle the rotor  205  when joined or connected together. 
     During operation, as the shaft  210  rotates, air may be compressed as it moves through various stages of the compressor section  104  with the rotor blades  215  and the stator blades  220  directing the air. The movement of the air may place resulting forces on the rotor blades  215  and the stator blades  220 . The rotation of the rotor  205  may create a centrifugal force that minimizes or prevents movement of the rotor blades  215 ; however, relative motion may occur between the stator blades  220  and the casing  225 ,  230 . As explained in greater detail below, embodiments of the invention may be utilized to increase the stability of the stator blades  220  and the bases of the stator blades. 
       FIG. 3  is a perspective view of one example stator  300  that may be utilized in association with various embodiments of the invention. With reference to  FIG. 3 , the stator  300  may include a stator base  305  and a stator blade  310  or stator vane that is connected to the stator base  305 . 
     According to an aspect of the invention, the stator base  305  may include one or more grooves  315  that facilitate the linking or connection of the stator base  305  to one or more other stator bases via a bracket, such as the bracket described in greater detail below with reference to  FIG. 4 . Any number of grooves  315  may be incorporated into the stator base  305  as desired in various embodiments of the invention. As shown in  FIG. 3 , certain embodiments may include a single groove  315  that follows the perimeter of the stator base  305  may be incorporated into the stator base  305 . The groove  315  may be positioned at any height along the stator base  305  as desired. For example, the groove  315  may be positioned at a height that is a relatively short distance below a surface of the stator base  305  to which the stator blade  310  is connected. The groove  315  may facilitate the receipt of a portion of a bracket that is used to link stator bases. For example, as shown in  FIG. 5  and discussed in greater detail below, prongs of a bracket may be inserted into the groove  315  of the stator base  305  on one side of the stator base  305  to link the stator base  305  to an adjacent stator base. Extensions from the bracket may extend into portions of the groove on opposite sides of the stator base  305  while the main body of the bracket extends into a portion of the groove that runs between the portions in which the extensions are received. 
     Although a single groove  315  is illustrated in  FIG. 3 , embodiments of the invention may include any number of grooves in the stator base  305  as desired. For example, in certain embodiments, two grooves may be provided on opposing sides of the stator base  305  and the two grooves may facilitate the receipt of a portion of a bracket that is used to link stator bases. As another example, in other embodiments of the invention, one or more slots or holes may be provided in the body of the stator base  305  to receive a portion of a bracket, such as, one or more corresponding extensions that extend from a main body of a bracket. A wide variety of different grooves and/or slots as well as shapes and configurations may be provided in the stator base  305  as desired to receive a portion of a bracket that facilitates the linking or joining of adjacent stator bases. The embodiments discussed above are provided by way of example only and are not meant to be limiting. 
     The one or more grooves may be formed in the stator base  305  by a suitable machining technique or machining process. Alternatively, the one or more grooves may be formed by a suitable casting technique or casting process during the production or manufacture of the stator bases. If a machining process is utilized, the machining may be conducted during the production or manufacture of the stator base  305  or, alternatively, after the stator base  305  has been manufactured. In this regard, stator bases that are already in use in a turbine or other machine may be retrofitted in order to facilitate linking of the stator bases in accordance with various embodiments of the invention. 
     Additionally, with reference to  FIG. 3 , the stator base  305  may include one or more projections  320  that facilitate securing the stator  300  to the casing or housing of a turbine component, for example, the housing or casing of the compressor section  104  discussed above with reference to  FIGS. 1 and 2 . Any number of projections  320  may be utilized as desired in various embodiments of the invention, for example, two projections. The one or more projections  320  may extend in the same plane from a surface  325  of the stator base  305 . The surface  325  of the stator base  305  from which the one or more projections  320  extend may be referred to as the mounting surface of the stator base  305 . The mounting surface  325  of the stator base  305  may be opposite a surface of the stator base to which the stator blade  310  is connected. To facilitate mounting of the stator  300  to the casing of the compressor section  104 , the stator base  305  may be inserted into a groove or slot (not shown) within the casing and secured within the groove or slot by the one or more projections  320 . The mounting surface  325  of the stator base  305  may have a curvature that corresponds to the curvature of the casing of the compressor section  104 . Additionally, the dimensions of the stator base  305  and stator blade  310 , for example, the curvature (of the mounting surface), size, and width of the stator base  305  and/or the clearance length of the stator blade  310  may be determined as desired based on the dimensions of the casing of the compressor section  104  and/or the row of stator blades or stage of the compressor section  104  that the stator  300  is included in. 
       FIG. 4  is a perspective view of one example bracket  400  that may be utilized to link two stators in a turbine, according to an illustrative embodiment of the invention. The bracket  400  may include a body portion  405  and a plurality of extensions or prongs  415 ,  420 ,  425 ,  430  that extend from the body portion  405 . A first set of extensions or prongs  415 ,  420  may extend from the body portion  405  in a first direction. In operation, the first set of extensions  415 ,  420  may be inserted into one or more corresponding grooves of a first stator base, as explained in greater detail below with reference to  FIG. 5 . Additionally, a second set of extensions or prongs  425 ,  430  may extend from the body portion  405  in a second direction. In operation, the second set of extensions  425 ,  430  may be inserted into one or more corresponding grooves of a second stator base, as explained in greater detail below with reference to  FIG. 5 . In this regard, two adjacent stator bases may be linked or connected by the bracket  400 . Any number of or different types of configurations for extensions or prongs may be utilized as desired in various embodiments of the invention. Additionally, various embodiments of the invention may include a different number of extensions in the first set of extensions and the second set of extensions. 
     According to certain embodiments of the invention, an angle θ may be formed between the first direction in which the first set of extensions  415 ,  420  extend and the second direction in which the second set of extensions  425 ,  430  extend. The angle θ may be an angle that facilitates the alignment of the various sets of extensions with the first and second stator bases. The inner surface of the casing or housing to which the first and second stator bases are connected may be curved or arcuate to facilitate surrounding a rotor. Thus, an angle may be formed between the first and second stator bases as they are connected to the casing or housing. The angle θ formed between the first direction and the second direction may account for the angle between the first and second stator bases. In this regard, the bracket  400  may be utilized to link the first and second stator bases while the first and second stator bases are connected to a casing or housing of a turbine component. The degree of the angle θ may be based at least in part on the curvature of casing or housing, and therefore, may vary in different embodiments of the invention. 
     Additionally, in certain embodiments of the invention, the body portion  405  of the bracket  400  may incorporate the angle θ. The body portion  405  may include portions that extend in different directions to account for the angle θ. Alternatively, the body portion  405  may include a curved portion that accounts for the angle θ. In other embodiments of the invention, at least one of the first set of extensions  415 ,  420  and the second set of extensions  425 ,  430  may extend from the body portion  405  of the bracket at an angle such that the angle θ is formed between the direction of the first set of extensions  415 ,  420  and the direction of the second set of extensions  425 ,  430 . 
     The bracket  400  may be formed from any number of suitable materials as desired in various embodiments of the invention. Examples of suitable materials from which the bracket may be formed include, but are not limited to, metals, metal alloys, ceramic materials, synthetic materials, composites, and/or any combination of these materials. Additionally, the bracket  400  may be formed utilizing a wide variety of different techniques or methods as desired in various embodiments of the invention. For example, the bracket  400  may be machined from one or more pieces of material. As another example, the bracket  400  may be molded as a single piece. As yet another example, various components of the bracket  400  may be molded or machined and then joined or connected together, for example, by a welding process, to form the bracket  400 . 
       FIG. 5  is a perspective view of two stator bases  505 ,  510  that have been linked by a bracket  515  in accordance with an illustrative embodiment of the invention. The two stator bases  505 ,  510  may each include similar components to the stator base  300  illustrated in  FIG. 3  and described above. Additionally, the bracket  515  may be similar to the bracket  400  illustrated in  FIG. 4  above. 
     As shown in  FIG. 5 , the bracket  515  may facilitate the linking of the first stator base  505  and the second stator base  510 . A first set of extensions  520  of the bracket  515  may extend into a groove  525  of the first stator base  505 . Similarly, a second set of extensions  530  of the bracket  515  may extend into a groove  535  of the second stator base. As shown, each stator base  505 ,  510  has a single groove that extends around the perimeter of the stator base  505 ,  510 . Thus, each extension of the first set of extensions  520  may extend into a respective corresponding portion of the groove  525  of the first stator base  505 . For example, a first extension may extend into a first portion of the groove  525  on a first side of the stator base  505  and a second extension may extend into a second portion of the groove  525  on a second side of the stator base  505  opposite the first side of the stator base. Similarly, each extension of the second set of extensions  530  may extend into a respective corresponding portion of the groove  535  of the second stator base  510 . Although the stator bases  505 ,  510  are described and shown as having a single groove, certain embodiments of the invention may include stator bases with multiple grooves, and each groove may be adapted or operable to receive an extension from a bracket. 
     Additionally, as shown in  FIG. 5 , a body portion  540  of the bracket  515  may extend into the groove  525  of the first stator base  505  and/or into the groove  535  of the second stator base  510 . For example, a first portion of the body portion  540  may extend into a corresponding portion of the groove  525  of the first stator base  505 . Similarly, a second portion of the body portion  540  may extend into a corresponding portion of the groove  535  of the second stator base  510 . In this regard, a relatively stronger connection may be facilitated between the stator bases  505 ,  510 . Additionally, the connection formed between the stator bases  505 ,  510  may have a relatively low air flow loss, as explained in greater detail below. 
     In certain embodiments of the inventions, the bracket  515  may be removably connected to the stator bases  505 ,  510  as a result of being inserted into the corresponding grooves  525 ,  535  of the stator bases  505 ,  510 . In other embodiments of the invention, the bracket  515  may be fixedly connected to one or more of the stator bases  505 ,  510  by any number of suitable connection means or connection methods, such as, screws, pins, welding, etc. 
     As a result of linking or connecting stator bases in a turbine component, a relatively semi-rigid ring of stator bases may be formed in a turbine component. The relatively semi-rigid ring of stator bases may be less susceptible to vibrations, stator rocking, and/or relative motion between the stators. As a result, wear on the stators and/or casing may be reduced, leading to relatively greater efficiency of the turbine component. 
     When mounted in a component of a machine, for example, a compressor section of a turbine, the first stator base  505  may be positioned at an angle relative to the second stator base  510 . As a result of this relative angle, a gap  545  may be formed between the first stator base  505  and the second stator base  510 . As shown in  FIG. 5 , the body portion  540  of the bracket  515  used to link the stator bases  505 ,  510  may extend between the stator bases  505 ,  510  within the gap  545 . In this regard, the bracket  515  may provide a surface that reduced or eliminates air or other gases from entering the gap  545 . For example, the bracket  515  may provide a surface slightly below the interior surface of the casing or housing to which the stator bases  505 ,  510  are connected. The surface provided by the bracket  515  may facilitate the decrease of losses due to air or other gases entering the gap  545 , leading to relatively greater efficiency within the turbine component. 
       FIG. 6  is a flowchart of one example of a method  600  for linking stators in a machine, according to an illustrative embodiment of the invention. The method  600  may begin at block  605 . At block  605 , two stator bases utilized in a machine component, for example stator bases  505 ,  510  shown in  FIG. 5 , may be provided. Each of the stator bases  505 ,  510  or base members may include one or more grooves that facilitate linking or connecting the two stator bases  505 ,  510  together with a connection bracket. 
     At block  610 , a bracket, such as, the bracket  515  illustrated in  FIG. 5 , may be provided for linking or connecting the two stator bases  505 ,  510  together. The bracket  515  may include a body and a plurality of extensions that extend from the body. A first set of two or more extensions extending from the body may be receivable by at least a portion of the one or more grooves of the first base member  505 . Similarly, a second set of two or more extensions extending from the body may be receivable by at least a portion of the one or more grooves of the second base member  510 . 
     At block  615 , the two stator bases  505 ,  510  may be linked or connected to one another by the bracket  515  within a machine component. For example, the two stator bases  505 ,  510  may be inserted into a groove or slot within the machine component with the bracket  515  positioned between the two stator bases  505 ,  510 . The bracket  515  may be operable to link the two stator bases  505 ,  510  together. Additionally, the bracket  515  may reduce relative motion or rocking between the two stator bases  505 ,  510  during the operation of the machine component, thereby leading to reduced wear within the machine component and relatively greater efficiency. The bracket  515  may also provide a surface between the two stator bases  505 ,  510  that improves air or gas flow within the machine component by reducing the amount of air or gas that enters a gap between the two stator bases  505 ,  510 . In this regard, the bracket  515  may further improve the efficiency within the machine component. 
     The method  600  may end following block  615 . 
     The operations described in the method  600  of  FIG. 6  do not necessarily have to be performed in the order set forth in  FIG. 6 , but instead may be performed in any suitable order. Additionally, in certain embodiments of the invention, more or less than all of the operations set forth in  FIG. 6  may be performed. 
     A wide variety of different type and shapes of brackets may be utilized as desired in various embodiments of the invention to link or connect one or more stators. The brackets may facilitate the linking or connection of one or more stators to reduce vibration or stator rocking of the one or more stators. Additionally, the brackets may provide a surface that facilitates the decrease of losses due to air or airflow entering the areas between adjacent stator bases. 
     While the invention has been described in connection with what is presently considered to be the most practical and various embodiments, it is to be understood that the invention is not to be limited to the disclosed embodiments, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims. 
     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 in 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.