Abstract:
A variable nozzle system can comprise a gas inlet ring, an opposing gas outlet ring, an actuation ring, guides, and vanes circumferentially spaced about and disposed between the gas inlet ring and the gas outlet ring. The gas inlet ring, the gas outlet ring, and the vanes can form nozzles, the nozzles being variable by rotation of the vanes about a pivot axis. The plurality of guides can extend from the gas inlet ring, the gas outlet ring, or the actuation ring, and the vanes can be connected to the actuation ring, so that each vane can be rotated by rotation of the actuation ring and by sliding against a respective guide from the plurality of guides. The actuation ring can have a gear rack and can be rotated by rotatable engagement of the gear rack with a pinion attached to the end of a rotatable gear shaft.

Description:
FIELD OF THE INVENTION 
       [0001]    This invention relates generally to radial inflow turbines, and more particularly, to a variable vaned nozzle system for such turbines. 
       BACKGROUND OF THE INVENTION 
       [0002]    A radial turbine is a practical device for converting influent (e.g. gas) pressure and temperature to shaft power. A radial inflow turbine employs an annular inlet surrounding a turbine wheel through which the influent under pressure is directed. To uniformly distribute the influent, vanes are disposed about the annular inlet to create nozzles. Many radial inflow turbines incorporate fixed geometry nozzle vanes, or airfoils, in an attempt to optimally guide the influent entering the rotor. In such cases the principal flow parameters, such as pressure, mass flow rate, and temperature remain in fixed proportion, and cannot be individually controlled. A variable nozzle provides an additional degree of control freedom, permitting independent control over inlet temperature, pressure, and flow through the turbine stage. 
         [0003]    These variable nozzles are often variable through the controlled pivotal motion of the vanes. Changing the stagger angle alters the throat between the vanes and changes the flow angle entering the rotor. The pivotal vanes are typically mounted between mounting rings which are positioned in a housing to either side of the annular inlet. In one example, the vanes are rotated by a series of horizontal and vertical wheels strung together on a cable. One wheel is rotated by a motor shaft connected to a motor. This one wheel, in turn, rotates each other wheel by drawing the cable clockwise or counterclockwise around each wheel. The vanes can rotate, for instance, by being connected to the axis of the wheels that rotate in a plane parallel with the plane of the mounting ring. 
         [0004]    In another device, each vane is attached to a rod which is positioned perpendicular to the influent flow direction. The rods, in a circumferential array, protrude through a movable annular back-wall, and are rotated by a linkage. The vanes in this assembly are adjusted in discrete movements. 
         [0005]    These types of nozzle systems are bulky, with many duplicate parts required to adjust the vanes. The bulkiness or clumsiness of these assemblies can be problematic. The additional parts and more complicated assemblies add to the manufacturing and assembly costs. Also, with the bulky, duplicate parts, sealing the influent flow paths to increase or maintain influent pressure and velocity through the nozzles can be difficult and complicated, or it can add further to the bulkiness. Each opening from the influent flow path that accommodates a part necessary for the vane adjustment is an opening that must be sealed. Duplicate parts create additional areas that need to be sealed Furthermore, these systems are limited or devoid in their adaptability for use with various existing radial inflow turbines because the parts are not easily repositioned or resized to accommodate differently configured or differently sized turbines. 
         [0006]    It would be advantageous to eliminate or reduce duplicate parts or simplify the nozzle adjustment mechanism. 
         [0007]    It would be advantageous to simplify the sealing arrangements and increase the sealing integrity, efficiency, or durability. 
         [0008]    It would be advantageous to lower costs associated with component manufacturing and system assembly. 
         [0009]    It would be advantageous to provide a nozzle assembly that can be easily adapted for use with a variety of existing radial inflow turbines. 
       SUMMARY OF THE INVENTION 
       [0010]    In one embodiment of the invention, a nozzle assembly for adjusting a radial inflow turbine is provided. The nozzle assembly can comprise a gas inlet ring, a gas outlet ring, an actuation ring, a plurality of guides, and a plurality of nozzle vanes. The gas outlet ring can be spaced apart from the gas inlet ring and the gas outlet ring can oppose the gas inlet ring. The actuation ring can have a central axis about which the actuation ring is rotatable with respect to the inlet ring and the outlet ring. The plurality of guides can be connected to at least one of the gas inlet ring, the gas outlet ring, and the actuation ring. The plurality of nozzle vanes can be circumferentially spaced and disposed between the gas inlet ring and the gas outlet ring, with each nozzle vane rotatable about a vane pivot axis with respect to the gas inlet ring and the gas outlet ring, and each nozzle vane in sliding engagement with a respective guide from the plurality of guides. 
         [0011]    In another embodiment of the invention, a variable nozzle system for a radial inflow turbine is provided. The variable nozzle system can comprise a first mounting ring, a second mounting ring, a plurality of vanes, a plurality of nozzles, an actuation ring, a gear rack, and a gear shaft. The second mounting ring can be spaced apart from the first mounting ring and the second mounting ring can oppose the first mounting ring. The plurality of vanes can be circumferentially spaced between the first mounting ring and the second mounting ring, and each vane can have a pivot point around which each vane is rotatable to adjust a plurality of nozzles. Each nozzle in the plurality of nozzles can be defined on four sides by the first mounting ring, the second mounting ring, and two vanes from the plurality of vanes. The actuation ring can have a central axis about which the actuation ring is rotatable with respect to the first mounting ring and the second mounting ring. The actuation ring can also be engaged with each nozzle vane from the plurality of nozzle vanes to drive the rotation of each nozzle vane. The gear rack can be attached to the actuation ring. The gear shaft can extend through the second mounting ring and can have a pinion engageable with the gear rack. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]    For a further understanding of the invention, reference will be made to the following detailed description of the invention which is to be read in connection with the accompanying drawing, where: 
           [0013]      FIG. 1  is a sectioned view of a nozzle assembly according to one embodiment of the invention; 
           [0014]      FIG. 2  is a detailed view of the sectioned view of  FIG. 1 ; 
           [0015]      FIG. 3  is a partially exploded perspective view of the nozzle assembly according to one embodiment of the invention; 
           [0016]      FIG. 4  is sectioned view of a nozzle assembly according to one embodiment of the invention; 
           [0017]      FIG. 5  illustrates an actuation ring, a gear rack, and rollers according to one embodiment of the invention; 
           [0018]      FIG. 6  illustrates an adjustable vane according to one embodiment of the invention; and 
           [0019]      FIG. 7  is a sectioned side view of the vane illustrated in  FIG. 6 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0020]    Referring now to the various figures of the drawings, there is illustrated one embodiment of the present invention. In referring to the various figures, like numerals shall refer to like parts. 
         [0021]      FIG. 1  depicts a cross-section of a nozzle assembly  12  used with a radial inflow turbine.  FIG. 2  is a detailed view of the embodiment depicted in  FIG. 1  highlighting one vane  14  and one adjustable nozzle  26 . Referring to  FIG. 1  and  FIG. 2 , the nozzle assembly  12  can be connected as part of the radial inflow turbine, and the radial inflow turbine can be used with an alternator (not shown) or another type of generator (not shown). The alternator or generator is typically used to convert energy from expanding influent to electrical power. The influent is typically a gas, though it could be one from a variety of fluids. The influent, at a high-temperature and a high-pressure, accelerates from the periphery of an inlet ring  20  and an outlet ring  16 , into the nozzle assembly  12 , directed by adjustable vanes  14 , with a tangential vector, toward a turbine rotor ( 4 , see  FIG. 4 ). A velocity vector of the influent, the mass flow rate of the influent, as well as intensive state properties of the influent such as temperature and pressure, influence the potential energy converted to shaft power, as the rotating turbine is connected to a shaft. The lowered pressure and lowered temperature influent exits the nozzle assembly  12  through the outlet ring  16 , a shroud  52 , and a diffuser  6 . The diffuser  6  is internal to a suction housing  8 . Electrical power converted by the alternator (not shown) can be connected to a load with conventional wiring. 
         [0022]      FIG. 3  is a partially exploded perspective view of the nozzle assembly  12  according to one embodiment of the invention. Referring to the partially exploded view of  FIG. 3 , the vanes  14  surround the turbine rotor  4  (see  FIG. 4 ) in a circumferential array. The vanes  14  are adjustably angled to direct the flow of influent into the rotor with a high degree of tangency. The number of vanes  14  in the nozzle assembly  12  typically varies from  11  to  19 , although other numbers of vanes  14  are conceived and can be used. In the exemplary embodiment illustrated in the figures,  16  vanes  14  are depicted. Turning away from the partially exploded view of  FIG. 1 , and turning momentarily to  FIG. 2  and  FIG. 3 , each vane  14  is positioned between the outlet ring  16  and an inlet ring  20 , creating an adjustable nozzle  26  in the space between each vane, the space bounded as well by the inlet ring  20  and the outlet ring  16 . 
         [0023]      FIG. 6  illustrates an adjustable vane  14  according to one embodiment of the invention, and  FIG. 7  is a sectioned side view of the vane  14  illustrated in  FIG. 6 . Referring to  FIG. 6  and  FIG. 7 , each vane  14  can have a slot  22 , approximately in a head end  24 . The slot  22  can extend completely through the width of the vane  14 , or the slot  22  can extend only partially through the width of the vane  14 . Each vane also has a bore or hole  28  in a tail end  18 . The hole  28  can accept a pin, bolt, screw, or another similar fastening or pivoting device. The shape of the vanes  14  can vary from the shape illustrated in  FIG. 6  and  FIG. 7 , as necessary to achieve desirable influent flow parameters. 
         [0024]    Referring again to  FIG. 1  and  FIG. 2 , through each slot  22  extends a guide  30 . The illustrated guide  30  is a pin or bolt. Each guide  30  is secured to either the inlet ring  20  on one side of its respective vane  14 , or to the outlet ring  16  on the opposite side of its respective vane  14 . Each guide  30  can also be secured to both the inlet ring  20  and the outlet ring  20 , as shown. Each vane  14  can move (e.g. rotate) so that the slot  22  of each vane slides, guided by each respective guide  30 . While each guide  30  illustrated is a pin, other alternative guides  30  are conceived. For instance, one or more rails or posts can extend or project from the inlet ring, the outlet ring, or the actuation ring, into the slot  22  or between vanes  14 , and guide the rotation of each respective vane  14 . 
         [0025]    One or more of the guides  30  can be a bolt  30  to fasten the inlet ring  20  to the outlet ring  16 , with the vanes  14  in between the inlet ring  20  and the outlet ring  16 . In the illustrated embodiment, three of the guides  30  are bolts  30 . The bolts  30  can be double headed or of another variety suitable to fasten securely to one or both of the inlet ring  20 , the outlet ring  16 , or another stationary structure within the nozzle assembly  12 . The bolts  30 , or other bolts used in the assembly, and the position of these bolts can be adapted for use with various existing turbines. For instance, the illustrated embodiment can be modified to use bolts that preexist in various, existing turbines as the bolts  30 , pins  30 , or other fastening or pivoting devices. 
         [0026]    A spacer  32  can be used around each guide pin  30  in each slot  22  in order to provide the appropriate clearance between the inlet ring  20  and the outlet ring  16  so that the vane  14  can move in a plane parallel to the plane of the inlet ring  20  and the outlet ring  16 . If the appropriate dimensional clearance between the inlet ring  20  and outlet ring  16  is not maintained when the vanes  14  are to be moved, then the vanes  14  might be squeezed between the inlet ring  20  and the outlet ring  16 , creating excessive friction that can obstruct proper movement of the vanes  14 . Other mechanisms known in the art can also be used to create a permanent or temporary clearance between the vanes  14  and the inlet ring  20 , and/or between the vanes  14  and the outlet ring  16 , so that the vanes  14  can move when actuated. 
         [0027]      FIG. 4  is a sectioned view of the nozzle assembly  12  according to one embodiment of the invention. Referring to  FIG. 4 , as well as  FIG. 3 , the vanes  14  are actuated, in part, by a connection with an actuation ring  34 . A pivot pin  36  can extend from the hole  28  of each vane to the actuation ring  34 . Each pivot pin  36  has a center axis about which each respective vane  14  rotates. The actuation ring  34  can be locted or sized otherwise in other embodiments, for instance, to accommodate use of the nozzle assembly  12  with various, existing turbines. 
         [0028]      FIG. 5  illustrates the actuation ring  34 , a gear rack  46 , and rollers  42  according to one embodiment of the invention. Referring to  FIG. 5 , the illustrated actuation ring  34  has three cutout sections  40 , with one roller  42  positioned in each cutout section  40  to guide and stabilize the rotational movement of the actuation ring  34 . Each roller  42  rotates about a roller bolt or roller pin  44  which is secured to the actuation ring  34 . This embodiment can be modified depending on the position of the actuation ring  34 . 
         [0029]    The actuation ring  34  also has, or is connected to, the gear rack  46 . The gear rack  46  has gear rack teeth  47  which fit with similar gear shaft teeth (not shown) on an end of a gear shaft  48  (see  FIG. 1  and  FIG. 2 ). A fine match between the gear rack teeth  47  and the gear shaft teeth (not shown) enables fine adjustment of the vanes  14 . 
         [0030]    Referring again to  FIG. 1  and  FIG. 2 , the gear shaft  48  extends through the outlet ring  16 , where the gear shaft  48  can be connected to and operated by (e.g. rotated about an axis of the gear shaft  48 ) an actuator or motor (not shown). A gear spacer  60  can provide support to the gear shaft  48  and help maintain its alignment. A gland  58  can provide a liquid-tight and gas-tight seal between the gear shaft  48  and the outlet ring  16 . Rotation of the gear shaft  48 , through interaction of the gear shaft teeth (not shown) with the gear rack teeth  47 , rotates the gear rack  47  and the actuation ring  34  about a central axis  10  of the nozzle assembly  12 , which is also the center axis of the actuation ring  34 . It is conceived that the center axis of the actuation ring  34  be offset radially from the central axis  10 , for instance, if necessary to adapt the nozzle assembly  12  to connect and work with an existing turbine. 
         [0031]    When the actuation ring  34  rotates, the axes of the pivot pins  36  and the respective holes  28  move rotationally around the central axis  10  along with the actuation ring  34 . The rotational movement of the vanes  14  along with the actuation ring  34 , with respect to the stationary guides  30  and the outlet ring  16 , causes the vanes  14  to rotate and the slots  22  to slide on the guides  30 . 
         [0032]    In an alternate embodiment, the slot  22  can be in the tail end  18 , while the hole  28  can be in the head end  24 . The nozzle assembly  12  can be modified accordingly, particularly including the pivot pins  36  and guides  30 . In this alternative embodiment, the guides  30  can function as, or be modified to function as pivot pins. Likewise, the pivot pins  36  can function as, or be modified to function as guides. When the actuation ring  34  rotates, the pivot pins  36  functioning (or modified to function) as guides move with the actuation ring  34 , causing the vanes  14  to slide on the pivot pins  36  functioning (or modified to function) as guides. Also, the vanes  14  rotate about the holes  28  and the guides  30  functioning (or modified to function) as pivot pins. 
         [0033]    In practical application, the need to adjust the nozzles  26  is dictated by external variables, such as a demand for power, changing input from the fuel source, a natural variation in the supply pressure, and so forth. Methods and means to detect external variables and operate a motor based on the external variable using a digital microprocessor, microcontroller, or other programmable controller are known. 
         [0034]    It is important to seal the nozzle assembly  12  properly in order to maintain pressure integrities and restrict influent flow to the desired path through the nozzle assembly  12 . As such, appropriate seals are used. For instance, the gland  58  provides one such seal. An O-ring or other seal can also be used to seal around each of the guide pins  30 , for instance, if the guide pins  30  extend all the way through the inlet ring  20  or the outlet ring  16 . Other seals and sealing mechanisms can be used as are known in the art and/or would be recognized by one skilled in the art. 
         [0035]    The terminology used herein is for the purpose of description, not limitation. Specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a basis for teaching one skilled in the art to employ the present invention. While the present invention has been particularly shown and described with reference to the exemplary embodiments as illustrated in the drawing, it will be recognized by those skilled in the art that various modifications may be made without departing from the spirit and scope of the invention. Those skilled in the art will also recognize the equivalents that may be substituted for elements described with reference to the exemplary embodiments disclosed herein without departing from the scope of the present invention. Therefore, it is intended that the present disclosure not be limited to the particular embodiment(s) disclosed as, but that the disclosure will include all embodiments falling within the scope of the appended claims.