Nozzle for a turbomachine turbine
View Patent ↗A turbine nozzle for a turbomachine, including inner and outer annular platforms connected together by vanes, the inner platform carrying annular elements of abradable material co-operating with annular wipers of a rotor of the turbomachine to form a labyrinth seal, these elements of abradable material being carried by annular sheet-metal sectors of substantially L-, S-, or C-shaped section that are fastened by brazing or welding at their outer peripheries to the inner platform and at their inner peripheries to the elements of abradable material.
1. A turbine nozzle for a turbomachine, the nozzle comprising:
two annular platforms, respectively an inner platform and an outer platform, interconnected by substantially radial vanes, the inner platform carrying annular elements of abradable material for co-operating with annular wipers of a rotor of the turbomachine to form a labyrinth type seal,
wherein the annular elements of abradable material are carried by annular sheet-metal sectors of substantially L-, S-, or C-shaped section that are mounted radially inside the inner platform and each of which has an outer periphery having a first weld or brazed joint with the inner platform and an inner periphery having a second weld or brazed joint with an element of abradable material or to a piece of sheet metal fastened to an element of abradable material.
2. A nozzle according to claim 1 , wherein each sheet-metal sector includes a radial wall with a cylindrical inner peripheral rim and is fastened via its outer peripheral edge to the inner platform.
3. A nozzle according to claim 2 , wherein the outer periphery of the radial wall of each sheet-metal sector is pressed against and fastened to an inner radial rib of the platform.
4. A nozzle according to claim 2 , wherein each sheet-metal sector includes a cylindrical outer peripheral rim pressed against and fastened to an inside surface of the inner platform.
5. A nozzle according to claim 2 , wherein the abradable material elements are fastened to inside surfaces of the cylindrical rims of the sheet-metal sectors.
6. A nozzle according to claim 2 , wherein each sheet-metal sector includes a rim extending towards the adjacent rotor disks to oppose hot gas escaping towards the rotor.
7. A nozzle according to claim 6 , wherein the rims of the sheet-metal sectors are formed by annular pieces of sheet metal fastened to the sheet-metal sectors by brazing or welding.
8. A nozzle according to claim 1 , wherein the inner platform includes a sectorized cylindrical wall, the sectors of the platform being castings and carrying sealing strips that are welded or brazed at one end on a platform sector and that are pressed in sliding contact at the other end against an adjacent platform sector in register with the sheet-metal sectors carrying the abradable material elements.
9. A turbomachine turbine, comprising at least one nozzle according to claim 1 .
10. A turbomachine, comprising a turbine fitted with at least one nozzle according to claim 1 .