BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic view of an example turbine engine of the present invention;
FIG. 2 illustrates a portion of a cross-section of a typical compressor for the example turbine engine of the present invention;
FIG. 3 is an enlarged view of section 3-3 from FIG. 2, illustrating a portion of example disks which are axially adjacent to one another.
FIG. 4 is a perspective view of a portion of the example disks of the present invention;
FIG. 4A is a top view of a an example knife edge seal inserted on the disk backbone prior to rotation;
FIG. 5 is a perspective view of an example knife edge seal of the present invention;
FIG. 6 is a perspective view of an example lock assembly of the present invention;
FIG. 7 is a cross-section of axially adjacent example disks where the lock assembly of FIG. 6 is in a lock position; and
FIG. 8 is a perspective view of an example knife edge seal for assembly adjacent to the lock assembly of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a schematic view of a turbine engine 10. Air is pulled into the turbine engine 10 by a fan 12 and flows through a low pressure compressor 14 and a high pressure compressor 16. Fuel is mixed with the oxygen and combustion occurs within the combustor 18. Exhaust from combustion flows through a high pressure turbine 20 and a low pressure turbine 22 prior to leaving the engine through the exhaust nozzle 24.
FIG. 2 illustrates a portion of a cross-section of a typical compressor including multiple disks 26 defining a compressor rotor. Each disk 26 rotates about an axis A located along the centerline of the turbine engine 10. A plurality of rotor blades 28 are mounted about the circumference of each of the disks 26. A plurality of stator blades 30 extend between the rotor blades 28 of axially adjacent disks 26, as shown.
Each disk 26 includes a disk rim 32. The disk rim 32 supports the rotor blades 28. A disk backbone 34 extends from each disk rim 32. A knife edge seal 36 is supported and retained by both of retaining flanges 38a and 38b (FIG. 3) which extend from each axially adjacent disk rim 34a and 34b. The knife edge seal segments 36 are preferably formed of the same material as the disk 26 or other materials such as ferrous, nickel, or ceramic materials. The knife edge seal 36 contacts the stator blades 30, as shown, to limit the air circulation within the compressor. In fact, the knife edge seal 36 contacts an abradable honeycomb material 31 associated with the stator blades 30.
FIG. 3 illustrates portions of example disks 26a and 26b which are axially adjacent to one another. A disk backbone 34a on the disk 26a is in contact with a disk backbone 34b of the axially adjacent disk 26b. The disk backbone 34a is preferably welded to the disk backbone 34b, illustrated by weld bead 64. However, the disk backbone 34a and the disk backbone 34b can also be bolted together or secured in another know manner. A retaining flange 38a extends from the disk 26a and a retaining flange 38b extends from the disk 26b. A plurality of knife edge seals 36 are arranged about the circumference of the disk backbones 34a and 34b. Each knife edge seal 36 is supported and retained by both the retaining flanges 38a and 38b.
Referring to FIG. 4, a perspective view of a portion of the disks 26a and disk 26b is shown. Details of the knife edge seals 36 can be seen in FIG. 5. As shown in FIG. 4A, to assemble the knife edge seals 36 lower seal body ears 40 are inserted past the retaining flanges 38a and 38b with the knife edge seal 36 oriented such that ears 40 extend parallel to flanges 38a and 38b. The knife edge seal 36 is then rotated, 90-degrees from the FIG. 4 position, about an edge seal axis E. A knife edge seal 36a which has been inserted between the retaining flanges 38a and 38b and only partially rotated about the edge seal axis E is shown at 100. Once rotated the knife edge seal 36 is prevented from movement past the retaining flanges 38a and 38b. Grooves 42 between the lower seal body ears 40 and the upper seal body 44 engage the retaining flanges 38a and 38b. The upper seal body 44 overlaps the retaining flanges 38a and 38b to minimize leakage past the knife edge seals 36 between the disks 26a and 26b. Knife edges 45 protrude from the upper seal body 44 to contact the stator blade 30. Preferably, there are multiple knife edges 45 extending from each upper seal body 44. Once assembled the knife edge seals 36 mate with each other by tab 41 interlocking with step 43 to provide a rigid structure. The tab 41 is overlapping step 43 to minimize leakage between the knife edge seals 36. Stress placed on disk 26 during compressor operation does not transfer to the knife edge seal 36 because the knife edge seals 36 are separate elements form the disks 26. The arrangement also allows for replacement of individual knife edge seals 36 without requiring an entire new disk 26.
An example of the assembly process of the knife edge seals 36 onto the disk backbones 34a and 34b is described. A lock assembly 46 is inserted between the retaining flanges 38a and 38b. The lock assembly 46, shown in FIG. 6, includes a lock housing 48 and a set screw 50. The lock assembly 46 is assembled in a similar manner to the knife edge seal 36. That is, the lock assembly 46 is inserted past the retaining flanges 38a and 38b and rotated 90-degrees about the edge seal axis E. After the lock assembly 46 is rotated the lock housing 48 interferes with and is prevented from movement past the retaining flanges 38a and 38b. The lock housing 48 has chamfers 52 to provide a surface for contacting the retaining flanges 38a and 38b. During assembly of the knife edge seals 36 the lock assembly 46 remains in a released position.
The process of inserting the lock assemblies 46 and knife edge seals 36 is repeated until all the knife edge seals 36 and lock assemblies 46 have been assembled onto the disk 26. The lock assemblies 46 should be assembled to be spaced from one another about the circumference of the disk backbones 34a and 34b. A plurality of knife edge seals 36 should be located between each lock assembly 46. Slack is left to provide enough room for the last knife edge seal 36 to be assembled. That is, to provide enough space to insert and then rotate the knife edge seal 36 into position.
In one example, there are eight lock assemblies 46. The number of lock assemblies 46 and the number and length of the knife edge seals 36 may vary. One skilled in the art would be able to determine the appropriate numbers and lengths of knife edge seals 36 and lock assemblies 46.
Referring to FIG. 7, once all the knife edge seals 36 have been assembled the slack used for assembly of the final knife edge seal 36 must be reduced to prevent the knife edge seals 36 from shifting and rotating during operation. The lock assemblies 46 can be moved from the released position to the locked position. The set screw 50 on each lock assembly 46 is tightened moving the lock assembly 46 into the lock position. To provide clearance for the protruding set screw 50 the knife edge seals 36b, shown in FIG. 8, adjacent to the lock assemblies 46 each define a lock interfitting portion 54. The lock interfitting portion 54 has a complementary shape to the portion of lock housing 48 which contacts the knife edge seal 36b. When the lock assembly 46 is moved to the locked position the set screw 50 acts against the disk backbone 34a to push the lock housing 48 upward from the disk backbone 34a. The upward movement the lock housing 48 causes the sides of the lock housing 60 to contact the sides 62 of the adjacent knife edge seal 36. The contact pushes the knife edge seals 36 away from each other reducing the slack.
The lock assemblies 46 each include a first interlocking feature 56 and the disk backbone 34a includes a second interlocking feature 58. When the lock assemblies 46 are in the lock position the first interlocking feature 56 and the second interlocking feature 58 lock together to prevent circumferential movement of the lock assemblies 46. In the example shown the first interlocking feature 56 is a rounded end of set screw 50 and the second interlocking feature 58 is a depression in the disk backbone 34a. The second interlocking feature 58 may be a continuous depression or a plurality of depressions spaced around the circumference of the disk backbone 34a at desired location. Of course, the second interlocking feature 58 may be formed in the second disk backbone 34b, or partially formed in both the first and second disk backbones 34a and 34b
Although the example embodiment discloses an arrangement of assembling knife edge seals onto a rotor disk for a compressor the arrangement may be used for any rotor and seal assembly.
Although a preferred embodiment of this invention has been disclosed, a worker of ordinary skill in this art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claims should be studied to determine the true scope and content of this invention.