Abstract:
A tube-type vortex reducer conducts cooling air in a compressor ( 1 ) of a gas turbine. Radial secondary air tubes ( 2 ) are arranged in a disk interspace ( 5 ) and attached to a compressor disk ( 3 ) with their radial outward end sections. The end sections of the secondary air tubes ( 2 ) are attached to a separate carrier ring ( 6 ), which is connected to a compressor disk ( 3 ).

Description:
This application claims priority to German Patent Application DE10310815.7 filed Mar. 12, 2003, the entirety of which is incorporated by reference herein. 
   BACKGROUND OF THE INVENTION 
   This invention relates to a tube-type vortex reducer. More particularly, the present invention relates to a vortex reducer for the conduction of cooling air in a compressor of a gas turbine, with radial secondary air tubes being arranged in a disk interspace and attached to a compressor disk with their radial outward end section. 
   In the state of the art, designs are known in which the secondary air tubes are fitted to corresponding locations on the disks by a pressing, riveting, screwing, snapping or forging process. These designs are disadvantageous in that adequate working space must be provided to enable the secondary air tubes to be installed with suitable tools. Therefore, the secondary air chamber, through which the secondary air enters the secondary air tubes, must be given a relatively large cross-section. This involves high manufacturing costs. Furthermore, the compressor disk may be damaged during the installation of the secondary air tubes. Since this disk is very expensive, risk of damage is a cost-relevant aspect of considerable importance. 
   BRIEF SUMMARY OF THE INVENTION 
   In a broad aspect, the present invention provides a tube-type vortex reducer of the type described at the beginning which, while being simply designed, is easily usable, dependable in operation, and can be produced cost-effectively. 
   It is a particular object of the present invention to provide solution to the above problems by the combination of the features described herein. Further advantageous embodiments of the present invention should be apparent from the description below. 
   The present invention accordingly provides for a secondary air tube, the end section of which is attached to a separate, segmented carrier ring which is separately connected to one of the compressor disks. The vortex reducer according to the present invention has a variety of merits. 
   As a first advantage, the inventive design enables the secondary air tubes to be attached by way of the carrier ring. Their installation immediately on the compressor disks is, therefore, not required. This precludes the compressor disks from being damaged. 
   A further, major advantage lies in the fact that the cross-section of the secondary air chamber can be kept small since no tools or similar equipment for the installation of the secondary air tubes need to be introduced into the secondary air chamber. Generally, this results in an increased stiffness of the compressor disks, which also provides for vibration reduction. The selected assembly method according to the present invention fully precludes disk damage, such as scratches, nicks or the like caused by the peening process, thus avoiding premature failure or rework. 
   It is particularly favorable if the secondary air tubes are attached to the carrier ring by way of a form fit. In a preferred form, this can be accomplished by means of a mounting shoe provided at the end section of the secondary air tubes which can be inserted into a slot of the carrier ring and secured by means of a locking element. This arrangement provides for a high degree of axial stability. It also facilitates assembly to a considerable extent. 
   In a preferred form, the carrier ring according to the present invention is given the shape of an angle section. This increases the inherent stability of the carrier ring and also enables the carrier ring to be provided with bolt holes for attaching the carrier ring to one of the compressor disks by means of axial bolts. The different positions of the slots and the bolt holes provide for an assembly-friendly, space-saving design, with each of the bolt holes being located centrally between adjacent slots. To facilitate assembly, the carrier ring, in accordance with the present invention, can be split into several, for example three, segments. The carrier can be inserted into the disk interspace without straining the segments. 
   For safe retention of the radial inward end section of the secondary air tube, it is particularly favorable to locate it on the compressor disk by means of a form fit. To accomplish this, no separate tooling is required which, again, would require appropriate working space or could lead to damage. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention is more fully described in the light of the accompanying drawings showing preferred embodiments. In the drawings, 
       FIG. 1  (Prior Art) is a schematic partial view of an embodiment according to the state of the art, 
       FIG. 2  (prior Art) is a view analogically to  FIG. 1 , of a further embodiment according to the state of the art, 
       FIG. 3  is a sectional view, analogically to  FIGS. 1 and 2  of a first embodiment of the present invention, 
       FIG. 4  is a partial front view of the arrangement according to the present invention, 
       FIG. 5  is a sectional view along line V—V of  FIG. 4 , 
       FIG. 6  is a sectional view along line VII—VII of  FIG. 4 , 
       FIG. 7  is a front view of the carrier ring in accordance with the present invention, and of individual segments forming this carrier ring, 
       FIG. 8  is a perspective view of the carrier ring in accordance with the present invention, 
       FIG. 9  is an enlarged partial representation of the carrier ring shown in  FIG. 8 , 
       FIG. 10  is a representation, analogically to  FIGS. 8 and 9 , of a first step for the assembly of the secondary air tubes to a carrier ring, 
       FIG. 11  is a representation of a final assembly step performed subsequently to that represented in  FIG. 10 , 
       FIG. 12  is an enlarged representation of the installation of the secondary air tubes by means of a locking element, 
       FIG. 13  is a representation, analogically to  FIG. 12 , of the finally assembled state, 
       FIG. 14  is a perspective partial view of the allocation of the carrier ring to the compressor disks. 
       FIG. 15  is a representation, analogically to  FIG. 14 , with preassembled secondary air tubes, 
       FIG. 16  is a representation, analogically to  FIGS. 14 and 15  with finally assembled secondary air tubes, and 
       FIG. 17  is a simplified sectional view of a portion of an inventive gas turbine, using the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 17  shows a partial sectional view of an inventive gas turbine. Reference numeral  1  shows a compressor comprising rotor blades  11  and stator vanes  12 . The rotor blades  11  are fixed to the compressor disks  3  or  4 , respectively. These form a disk interspace  5  in which several, radial secondary air tubes  2  are arranged. Reference numeral  13  indicates a combustion chamber, while reference numeral  14  designates a turbine in schematic representation. The arrows schematically indicate the route of the secondary air flow. 
     FIGS. 1 and 2  show embodiments according to the state of the art. Obviously, the end sections of the secondary air tubes are riveted, as indicated by the reference numeral  15 . Reference numeral  16  designates an additional carrier disk which represents an additional volume element and is fitted in the disk interspace  5 . 
     FIG. 2  shows a similar embodiment, with a riveted joint again being indicated by the reference numeral  15 . As becomes apparent, a very large secondary air chamber  17  must be provided to allow the riveting tool to be introduced. 
     FIG. 3  shows a first embodiment according to the present invention. As can be seen, the free end of the secondary air tube is located on an angle-section carrier ring  6 . The secondary air chamber  17  can here be very small since no pressing tool needs to be introduced into it. The carrier ring  6  is attached to the compressor disk  3  by means of bolts  18 . The bolt  18  also holds a mounting flange  19  of the further compressor disk  4 . Thanks to the present invention, the carrier ring  6  can be dimensioned and designed such that a very favorable design of the mounting flange  19  can be achieved, resulting in an enlarged, improved radius  20  of said mounting flange  19 . Further, it is possible to minimize a chamber  21  at the radially outward end of the compressor disk  3 . 
     FIG. 4  shows an axial partial view illustrating that the bolts  18  and the secondary air tubes  2  are offset relative to each other in alternation on the circumference. 
     FIG. 5  shows an enlarged partial sectional view along line V—V of  FIG. 4 , showing again in detail the carrier ring  6  and the bolts  18  as well as further locking elements and the nuts required. 
     FIG. 6  shows a sectional view along line VII—VII of  FIG. 4  with the secondary air tubes in the installed state. In particular, a mounting shoe  7 , which is detailed hereinafter, is shown on the end section of each secondary air tube  2 . Furthermore, a locking element  9  for the retention of the mounting shoe  7  is shown, this locking element  9  also being explained hereinafter. 
     FIG. 7  is an axial view of the carrier ring  6  according to the present invention. As can be seen, individual mounting pads  22  with bolt holes  10  for the bolts  18  are provided. 
   As becomes apparent from  FIG. 7 , the carrier ring  6  may include individual segments a, b and c to facilitate installation. Reference numeral  23  indicates the splits, these being located and arranged essentially radially (upper split in  FIG. 7 ) as well as diagonally to the upper split. The large arrows  24  indicate the installation direction of the segments a, b and c. 
     FIG. 8  is a perspective representation of the carrier ring  6  according to the present invention. The figure clearly shows that a slot  8  is provided between adjacent mounting pads  22  into which the mounting shoe  7  of the secondary air tube  2  can be inserted. Reference numeral  25  designates a registering skew, or a chamfered, skewed area of the locking element  9 , which enables the mounting shoe  7  to be accurately fitted. See also,  FIGS. 9 ,  10 ,  12  and  13 . The chamfered area of the locking element  9  faces radially outwardly and is configured to engage a corresponding radially inwardly chamfered area of the mounting shoe  7  of the secondary air tube  2 . This locking engagement secures the secondary air tube  2  in place and prevents the secondary air tube  2  from moving radially inwardly. The radially outwardly and inwardly facing portions can have alternative configurations other than chamfered. 
     FIGS. 10 and 11  show assembly steps, illustrating the manner in which the individual mounting shoes  7  of the secondary air tubes  2  are inserted into the slots  8 .  FIG. 11  shows the finally assembled, inserted state. Subsequently, as shown in  FIG. 12 , the locking element  9  interacts with the mounting shoe  7  to clamp the secondary air tube  2  in place. 
     FIGS. 14 to 16  again show various assembly states in different perspective.  FIG. 14  shows a state in which the carrier ring  6  is fitted between the two compressor disks  3  and  4 .  FIG. 15  shows the pre-assembly of the secondary air tubes  2  (analogically to  FIG. 10 ).  FIG. 16  is a representation of the finally assembled state, analogically to  FIG. 13 . 
   As becomes apparent, in particular, each of the radially inward end sections of the secondary air tubes  2  is provided with a flange  26  (see  FIG. 11 ) which is insertable into a profiled, essentially circular recess  27  (see  FIG. 16 ) of the compressor disk  4 . This arrangement enables the free end sections of the secondary air tubes  2  to be retained effectively. 
   LIST OF REFERENCE NUMERALS 
   
       
         1  Compressor 
         2  Secondary air tube 
         3  Compressor disk 
         4  Compressor disk 
         5  Disk interspace 
         6  Carrier ring 
         7  Mounting shoe 
         8  Slot 
         9  Locking element 
         10  Bolt hole 
         11  Rotor blade 
         12  Stator vane 
         13  Combustion chamber 
         14  Turbine 
         15  Riveted joint 
         16  Carrier disk 
         17  Secondary air chamber 
         18  Bolt 
         19  Mounting flange 
         20  Radius 
         21  Chamber 
         22  Mounting pad 
         23  Split 
         24  Arrow 
         25  Registering skew 
         26  Flange 
         27  Recess