Abstract:
An adjustable supporting assembly in a fluid driven machine with a rotating shaft includes a housing having a chamber with an inner surface, a stationary flowpath component comprising at least first and second portions, and at least one supporting structure. The stationary flowpath component extends around and radially outward from the shaft to an outer surface. The stationary flowpath component is also disposed within the chamber with the outer surface of the stationary flowpath component adjacent to the inner surface of the housing. The supporting structure supports the first portion of the stationary flowpath component in a first position and is adjustable to other positions. The supporting structure also secures the first and second portions of the stationary flowpath component together.

Description:
This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/107,749 filed on Nov. 10, 1998 which is herein incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     This invention relates generally to a fluid driven machine and, more particularly, to an adjustable supporting assembly for flowpath components in a machine, such as a turbine, and a method thereof. 
     BACKGROUND OF THE INVENTION 
     In a turbine, alignment of stationary flowpath components with respect to rotating flowpath components, such as a shaft or rotor wheel, is crucial. Typically, some spacing must be provided between the stationary and rotating flowpath components. If the alignment is off, then the spacing between the stationary and rotating flowpath components may be to large or to small. If the spacing is to large, then there may be to much leakage of a motive fluid, such as steam, between the stationary and rotating flowpath components and thus a decrease in overall efficiency of the turbine. If the spacing is to small, then the stationary flowpath components may rub against the rotating flowpath components damaging the turbine. 
     Transient temperature differentials typically experienced by the turbine during normal operations make it difficult to properly align and space the stationary flowpath components with respect to the rotating flowpath components. When stationary flowpath components lose alignment with the rotating flowpath components the efficiency of the turbine is decreased and/or the turbine may be damaged. 
     One technique for supporting and centering stationary flowpath components with respect to the rotating shaft involves the use a pair of lug arrangements for the upper half of a diaphragm and another pair of lug arrangements for the lower half of the diaphragm. One example of such a system is disclosed in U.S. Pat. No. 2,247,423 to Webster which is herein incorporated by reference. With this technique, proper centering of the diaphragm requires that the diaphragm&#39;s center coincide with the center or axis of the casing which means that the face of the lower half of the diaphragm be located in a plane through the joint or dividing plane between the casing halves. Lug arrangements on opposite sides of the lower half of the diaphragm are used to achieve this and hold the diaphragm in place in the lower half of the casing. Similarly, lug arrangements on opposite sides of the upper half of the diaphragm are used to locate the face of the upper half of the diaphragm in a plane through the joint or dividing plane between the casing halves. Additionally, the lower half of the diaphragm is centered horizontally in the lower casing half by a vertical pin secured in a groove in the bottom portion of the lower casing half and slidably projecting into a vertical bore in the lower half of the diaphragm. 
     Unfortunately, this technique has some problems. For example, when this technique is used, proper sealing at the split line between halves of the diaphragm is difficult because the lug arrangements are concerned with centering the lower and upper halves of the diaphragm with the face at the split line for the lower and upper casing halves, respectively, and not with forming a tight seal between the diaphragm halves. Additionally, with this technique the diaphragm halves are not properly aligned because they are aligned with respect to the casing, not the shaft. 
     SUMMARY OF THE INVENTION 
     An adjustable supporting assembly in accordance with one embodiment of the present invention in a fluid driven machine with a rotating shaft includes a housing having a chamber with an inner surface, a stationary flowpath component comprising at least first and second portions, and at least one supporting structure. The stationary flowpath component extends around and radially outward from the shaft to an outer surface. The stationary flowpath component is also disposed within the chamber with the outer surface of the stationary flowpath component adjacent to the inner surface of the housing. The supporting structure supports the first portion of the stationary flowpath component in a first position and is adjustable to other positions. The supporting structure also secures the first and second portions of the stationary flowpath component together. 
     An adjustable support in accordance with another embodiment of the present invention in a fluid driven machine with a rotating shaft includes a housing having a chamber with an inner surface, a stationary flowpath component comprising at least first and second portions, and at least one supporting structure. The stationary flowpath component extends around and radially outward from the shaft to an outer surface and is disposed within the chamber with the outer surface of the stationary flowpath component adjacent to the inner surface of the housing. The supporting structure extends through a first passage in the first portion of the stationary flowpath component, past a split line separating the first and second portions of the stationary flowpath component, and into a second passage in the second portion of the stationary flowpath component. The supporting structure adjusts the position of at least the first portion of the stationary flowpath component with respect to the shaft and the inner surface of the housing. 
     An adjustable support in accordance with another embodiment of the present invention in a fluid driven machine with a rotating shaft includes a housing having a chamber with an inner surface, a stationary flowpath component comprising at least first and second portions, at least one supporting structure, and a pin and a notch shaped to mate with the pin. The stationary flowpath component extends around and radially outward from the shaft to an outer surface and is disposed within the chamber with the outer surface of the stationary flowpath component adjacent to the inner surface of the housing The supporting structure is adjustable to alter a position of at least the first portion of the stationary flowpath component with respect to the shaft and the inner surface of the housing. The pin and the notch are located along the inner surface of the housing and the outer surface of the first portion of the stationary flowpath component. A first clearance is defined along at least one side of the pin. 
     A method for adjusting components in a chamber of a housing of a fluid driven machine, the housing having a shaft which rotates about a first axis and is located at least partially within the chamber in accordance with another embodiment of the invention includes a few steps. First, a position of a first portion of a stationary flowpath component with respect to the shaft in the chamber is adjusted with at least one supporting structure. Next, a second portion of the stationary flowpath component is secured to the first portion of the stationary flowpath component with the supporting structure. 
     With the present invention, the apparatus and method for aligning the halves of the stationary flowpath components with respect to the rotating shaft is simplified. Instead of using arrangements which separately adjusted the upper and lower halves of the stationary flowpath components, the present invention uses one arrangement to align both the upper and lower halves of the stationary flowpath component. As a result, the present invention is simpler and quicker to use because only one arrangement needs to be adjusted to align both halves. The simpler design also helps to reduce the overall cost of the alignment mechanism when compared to prior systems. 
     The present invention also provides a tighter seal between the upper and lower halves of the stationary flowpath components which helps to reduce or eliminate leakage between the halves of the stationary flowpath component and thus increase the overall efficiency of the machine. This tighter seal is accomplished by securing the upper and lower halves of the stationary flowpath component together with the same structure which is used to align the lower half (and thus also the upper half) of the stationary flowpath component. 
     Additionally, with the present invention the assembly and disassembly of the machine is also much easier and is less likely to result in damage to the stationary flowpath components. Unlike the prior systems described earlier, with the present invention the upper half of the stationary flowpath component is secured to the lower half of the stationary flowpath component and not to the upper half of the casing. 
     Further, with the present invention both lateral movement along with vertical movement of the stationary flowpath component with respect to the shaft is possible. As a result, more positions for the proper alignment of the stationary flowpath component are possible ultimately resulting in a more efficient machine. In some applications, alignment of the split line for the diaphragm halves is off center with respect to the halves of the casing. 
     Another advantage of the present invention is the ability for the turbine case and flowpath components to grow/shrink thermally and maintain alignment. No rigid connection is used between the two components which would stress or move the components relative to each other if their shape changes. A large enough space/clearance is provide between the inside of the turbine case and outside diameter/surface of the flowpath component. The posts which support the flowpath components are able to slide within pockets in the turbine case. The bottom pin maintains the centering of the turbine and accommodates any vertical difference between the turbine case and flowpath components by sliding within a groove in the flowpath component, yet has a tight side clearance to maintain the steampath component lateral position. 
     Another feature of the present invention is the flowpath component is locked into the turbine case lower half. The weight of the steampath component is not relied on to prevent it from lifting. This lifting of the steampath component can occur during the lifting of the turbine case upper half for maintenance or during turbine operation, with the combination of pressure and temperature effects. A lifting in either case can change the seals at the center of the flowpath component. 
     Yet another advantage of the present invention is the simple machining requirements for making the assembly. The flowpath component has only a partially threaded through hole on each side of the lower half and the post is sized to fit within the tap drill through hole. The post may be a round piece with a notch cut to create a foot like feature which engages in an opening in the turbine case. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a cross-sectional view of turbine with adjustable supports for turbine flowpath components in accordance with the present invention; 
     FIG. 2 is an exploded, perspective view of an adjustable support in accordance with the present invention; 
     FIG. 3 is partial, top, cross-sectional view of an adjustable support in accordance with the present invention; 
     FIG. 4 is a partial, side, cross-sectional view of an adjustable support in accordance with the present invention; 
     FIG. 5 is an enlarged, side, cross-sectional view of a passage in a stationary flowpath component for the adjustable support; and 
     FIG. 6 is an enlarged, not to scale, side, cross-sectional view of a pin and notch in a stationary flowpath component and a housing. 
    
    
     DETAILED DESCRIPTION 
     An adjustable supporting assembly  10  in accordance with one embodiment of the present invention in a machine  12  is illustrated in FIGS. 1 and 2. The machine  12  includes a housing  14  having a chamber  16  with an inner surface  18  and a stationary flowpath component  20 . The present invention provides a number of advantages including simplifying the process for aligning the stationary flowpath component  20  with respect to a shaft  22 , providing both lateral and vertical movement by just turning a threaded bushing. The present invention also provides a tighter seal between the upper and lower halves  20 ( 1 ) and  20 ( 2 ) of the stationary flowpath component  20 . Further, the present invention makes the assembly and disassembly of the housing  14  of the machine  12  easier by securing the upper half  20 ( 2 ) of the stationary flowpath component  20  to the lower half  20 ( 1 ) instead of to an upper half  14 ( 2 ) of the housing  14 . 
     Referring more specifically to FIG. 1, the machine  12  is a turbine in this particular embodiment, although other types of fluid driven machines  12  can be used. The shaft  22  extends along and rotates about axis A—A in the machine  12 . Rotor wheels  24  are mounted on or are integrally formed with the shaft  22  and extend radially outward from the shaft  22  to a radially outermost periphery. 
     The machine  12  also includes the housing  14  or casing which is connected between an inlet casino  26  and an exhaust casing  24 . The housing  14  defines an inner chamber  16  which surrounds the shaft  22 , the rotor wheels  24 , and the stationary flowpath components  20 , which in this particular embodiment are diaphragms although other types of stationary flowpath components  20  can be used. Since in this example the other stationary flowpath components  20  in FIG. 1 are identical to the one described below with reference to FIGS. 2-6, the other stationary flowpath components  20  will not be discussed here. The chamber  16  retains the working or motive fluid in the machine  12 . The direction of flow of a motive fluid, such as steam, in the machine  12  is illustrated by the arrows B in FIG.  1 . 
     Referring to FIGS. 2 and 4, the housing  14  is split into halves  14 ( 1 ) and  14 ( 2 ) along a split line C—C in this particular embodiment, although the housing  14  can be split into more than two parts as needed or desired. The halves  14 ( 1 ) and  14 ( 2 ) of the housing are held together by bolts or other securing devices (not shown). A groove  30  is formed along an inner surface  18  of the chamber  16  in the housing  14  and extends substantially around the inner circumference of the chamber  16  of the housing  14 , although other shapes and configurations for the groove  30  are possible, such as having a discontinuous groove. The groove  30  is designed to receive an outer edge or lip  32  along an outer surface  34  of the stationary flowpath component  20 . Alternatively, a protrusion (not shown) could be formed along the inner surface  18  of the chamber  16  in the housing  14  which fits within a groove (not shown) along an outer surface  34  of the stationary flowpath component  20 . 
     Referring to FIGS. 2,  4 , and  6 , in this particular embodiment one end  42  of a centering pin  36  is designed to fit snugly within a hole  38  formed along the inner surface  18  of the chamber  16  in the housing  14 . The centering pin  36  extends from this hole  38  towards the shaft  22  or shaft opening  40  in the stationary flowpath component  20 . The other end  44  of the centering pin  36  is designed to fit within a matching slot  46  in the outer surface  34  of the stationary flowpath component  20 . In this particular embodiment, a clearance (not to scale)  48  is provided for on each side of the other end  44  of the pin  36  in the outer surface  34  of the stationary flowpath component  20  to permit some rotational movement of the stationary flowpath component  20 , although the other end  44  of the centering pin  36  could be designed to fit snugly within a hole  46  in the outer surface  34  of the stationary flowpath component  20  with a clearance provided for on each side of the one end  42  of the pin  36  in the hole  38  in the housing  14 . Additionally, a space  48  may be provided along only one side of the one or the other end  42  or  44  of the pin  36 . The space or spaces  48  permit some lateral or rotational movement of the stationary flowpath component  20  so that proper alignment can be achieved. In this particular embodiment the space  50  on each side ranges between about 0.000 and 0.002. The centering pin  36  is used to orient one half  20 ( 1 ) of the stationary flowpath component  20  in to the one half  14 ( 1 ) of the housing  14 . 
     Referring to FIGS. 2-6, one of the stationary flowpath components  20  is illustrated. The stationary flowpath component  20  is spaced from and extends radially outward from the shaft  22  to the outer surface  34 . The stationary flowpath component  20  is split into halves  20 ( 1 ) and  20 ( 2 ) along the split line C—C, although the stationary flowpath component  20  can be split into more than two parts as needed or desired. As discussed earlier, in this particular embodiment, the stationary flowpath component  20  has the outer edge or lip  32  along the outer surface  34  which mates with the groove  30  in the housing  14 , although other types of mating arrangements between the outer surface  34  of the stationary flowpath component  20  and the inner surface  18  of the chamber  16  can be used. 
     A pair of passages  50  are formed in one half  20 ( 1 ) of the stationary flowpath component  20 , although the number of passages  50  can vary. Each of the passages  50  extends from the split line C—C for the stationary flowpath component  20 , through a portion of the stationary flowpath component  20 ( 1 ), and out through the outer surface  34  of the stationary flowpath component  20 . A slot or notch  52  is formed in the inner surface  18  of the chamber  16  of the half  14 ( 1 ) of housing  14  adjacent to the opening  54  for each of the passages  50  at the outer surface  34  of the half  20 ( 1 ) of the stationary flowpath component  20 . Each of the passages  50  in this particular example has a threaded portion  56  adjacent the split line C—C and an unthreaded portion  58  below that, although the entire passage  50  could be threaded. The circumference or outer envelope of each of the passages  50  is larger than the circumference or outer envelope of each of the guide posts  60  which are inserted into the passages  50 . 
     Another pair of passages  62  are formed in the other half  20 ( 2 ) of the stationary flowpath component  20 , although the number of passages  62  can vary. Each of these passages  62  also extends from the split line C—C for the stationary flowpath component  20 , through a portion of the half  20 ( 2 ) of the stationary flowpath component  20 , and out through the outer surface  34  of the stationary flowpath component  20 . When the halves  20 ( 1 ) and  20 ( 2 ) of the stationary flowpath component  20  are brought together along the split line C—C, the passages  50  are aligned with the passages  62 . 
     A pair of pockets  64  are also formed in the other half  20 ( 2 ) of the stationary flowpath component  20 , although the number of pockets  64  can vary as needed or desired. Each of the pockets  64  extends in from the outer surface  34  of the stationary flowpath component  20  in the general direction of the shaft  22  and provides access to the passages  62 . 
     As discussed earlier, a guide post  60  is located in each of the passages  50 . The circumference or outer envelope of each of the guide posts  60  is less than the circumference or outer envelope of each of the passages  50 . In this particular embodiment, one end of each of the guide posts  60  has notch or recess  66  cut in adjacent one end to form a lip or foot  68  adjacent the bottom of the post  60 . The lip  68  is shaped to mate with the slot or notch  52  formed in the inner surface  18  of the chamber  16  of the housing  14  adjacent to the opening  54  for each of the passages  50 . 
     A bushing  70  is located in the threaded portion  56  of each of the passages  50 . The bushing  70  has an outer surface with threads which mate with the threads  56  along the inner surface of the passage  50 . When the bushings  70  are threaded into their respective passages  50 , one end of each of the bushings  70  is seated against one end of each of the guide posts  60 . The bushings  70  and guide posts  60  secure the one half  20 ( 1 ) of the stationary flowpath component  20  to the one half  14 ( 1 ) the housing  14  and are used to align the one half of the stationary flowpath component  20  with respect to the shaft  22 . 
     In this particular embodiment, one end of the bushing  70  extends up past the split line C—C for the one half  20 ( 1 ) of the stationary flowpath component  20 , although the bushing  70  could be located below the split line C—C. If a portion of one or both of the bushings  70  extends up past the split line C—C for the one half  20 ( 1 ) of the stationary flowpath component  20 , then the passage or passages  62  in the other half  20 ( 2 ) of the stationary flowpath component  20  are designed to clear with or fit over these portions of the bushings  70 . 
     A bolt  72  or other type of securing device extends from the passage  62  in the other half  20 ( 2 ) of the stationary flowpath component  20  into the passage  50  in the one half  20 ( 1 ) of the stationary flowpath component  20 . In this particular embodiment, the bolt  72  is screwed into a threaded passage  74  into the top of the post  60 . The bolt  72  passes through a clearance hole in the bushing  70  and threads into the post  60 . When the bolt  72  is tightened, the post  60 , bushing  72  upper and lower halves  20 ( 1 ) and  20 ( 2 )of the flowpath component  20  became a rigid assembly. The bolt  72  is used to secure the other half  20 ( 2 ) of the stationary flowpath component  20  to the one half  20 ( 1 ) of the stationary flowpath component  20  and not to the other half  14 ( 2 ) of the housing  14 . By not relying upon the other half  14 ( 2 ) of the housing  14  to hold the other half  20 ( 2 ) of the stationary flowpath component  20  in place, the other half  14 ( 2 ) of the housing  14  is easier to remove and the other half  20 ( 2 ) of the stationary flowpath component  20  is less likely to damaged. Movement of the other half  20 ( 2 ) of the stationary flowpath component  20  can result in seal damage. 
     The operation of one particular embodiment of the adjustable supporting assembly  10  in a machine  12  will be illustrated with reference to FIGS. 1,  2 ,  4 , and  6 . First, the halves  14 ( 1 ) and  14 ( 2 ) of the housing  14  are separated to expose the chamber  16 . Next, one end of a guide post  60  with a lip  68  formed by a notch  66  in the post  60  is secured in a notch  52  in the inner surface  18  of the chamber  16 . 
     Once the guide posts  60  are in place, one half  20 ( 1 ) of the stationary flowpath component  20  is placed in the one half  14 ( 1 ) of the housing  14  with the guide posts  60  being inserted into the passages  50  on opposing sides of the one half  20 ( 1 ) of the stationary flowpath component  20 . Additionally, in this particular embodiment an outer edge  32  on the outer surface  34  of the one half  20 ( 1 ) of the stationary flowpath component  20  is seated within the groove  30  along the inner surface  18  of the chamber  16 . Further, a centering pin  36  is used to generally orient the one half  20 ( 1 ) of the stationary flowpath component  20  in the one half  14 ( 1 ) of the housing  14 . In this particular embodiment, the pin  36  extends from the one half  14 ( 1 ) of the housing  14  into a slot  46  in the outer surface  34  of the one half  20 ( 1 ) of the stationary flowpath component  20  with a clearance  48  adjacent each side of the pin  36 , although other orientations of the pin  36  and hole  46  are possible. 
     Next, the bushings  70  are screwed into the threaded portion  56  of each of the passages  50 . One end of the bushings  70  eventually are seated against one end of the posts  60 . By rotating each of the bushings  70  an equal amount, the one half  20 ( 1 ) of the stationary flowpath component  20  is moved towards or away from the shaft  22  for alignment purposes. By rotating one or the other of the bushings  70 , the half  20 ( 1 ) of the stationary flowpath component  20  is rotated or moved laterally to the right or left with respect to the shaft  22 . The amount of rotation or lateral movement may be limited by the amount of space  48  provided on the side or sides of the centering pin  36 , if a centering pin  36  is used. 
     Next, the other half  20 ( 2 ) of the stationary flowpath component  20  is placed on the one half  20 ( 1 ) of the stationary flowpath component  20  along the split line C—C. The bushings  70  may protrude above the split line C—C extending into the passages  62  in the other half  20 ( 2 ) of the stationary flowpath component  20 . 
     Once the passages  50  and  62  in the halves  20 ( 1 ) and  20 ( 2 ) of the stationary flowpath component  20  are aligned along the split line C—C, the bolt  72  or other securing device is inserted into the passage  62  in the other half  20 ( 2 ) of the stationary flowpath component  20  and is screwed down into the threaded passage  74  in the guide post  60  on each side of the one half  20 ( 1 ) of the stationary flowpath component  20 . This secures the halves  20 ( 1 ) and  20 ( 2 ) of the stationary flowpath components  20  together. 
     Finally, the other half  14 ( 2 ) of the housing  14  is placed over the one half  14 ( 1 ) of the housing  14  and so that an outer edge  32  on the outer surface  34  of the other half  20 ( 2 ) of the stationary flowpath component  20  is seated within a groove  30  along the inner surface  18  of the chamber  16  of the housing  14 . The halves  14 ( 1 ) and  14 ( 2 ) of the housing  14  are then secured together. 
     Having thus described the basic concept of the invention, it will be rather apparent to those skilled in the art that the foregoing detailed disclosure is intended to be presented by way of example only, and is not limiting. Various alternations, improvements, and modifications will occur and are intended to those skilled in the art, though not expressly stated herein. These alterations, improvements, and modifications are intended to be suggested hereby, and are within the spirit and scope of the invention. Accordingly, the invention is limited only by the following claims and equivalents thereto.