US 3423071 A
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Jan. 21, 1969 H. K. NOREN 3,423,071
TURB INE VANE RETENTION Filed July v17, 1967 BY Z s United States Patent O 6 'Claims ABSTRACT OF THE DISCLOSURE A nozzle vane retention construction adapted principally for use downstream of an annular type combustion chamber in a gas turbine engine. The construction provides both vane retention capability and vane removal and replacement capability.
Background of invention This invention relates to a gas turbine nozzle vane end retaining construction.
In a typical gas turbine engine, the compressor compresses a gas, normally air, and feeds it to a combustion chamber where it is mixed with fuel and burned increasing the pressure of the gas. The high pressure gas leaves the combustion chamber and passes rst through a transition duct and then a first-stage nozzle. From here the gas is passed rearwardly through the turbine sections of the engine and exhausted.
The vanes of the first-stage nozzle ring are the iirst portions of the turbine section to come in contact with the hot gases produced in the combustion chamber. Consequently, these vanes are generally the parts most likely to become burned, eroded or otherwise damaged and are oftentimes found to require frequent replacement. The problem of replacing vanes which have become burnt and of preventing any portions of the damaged vanes from moving through the turbine section and causing damage thereto is aggravated when the combustion chamber is an annular combustion chamber. This is so because with this type of combustion chamber, access to the inner retaining section of the vanes is not possible. Therefore, vane retention at the inner section and vane replacement capability is not compatible.
While the prior art discloses many schemes for vane retention, the prior art constructions apparently did not consider the problem presented by using an annular combustion chamber. In fact, the prior art construction generally defines a construction wherein the inner vane end is bolted to a supporting casing. When an annular combustion burner is used, if the inner ends of the vanes are bolted to a casing, individual vanes cannot be removed because the annular combustion casing prevents access to the bolts. It should therefore be clear that the use of an annular combustion chamber with the prior art constructions would force a choice between either vane retention or vane removal capability.
Summary of the invention It is the primary object of this invention to provide a nozzle vane retaining construction which will facilitate removal and replacement of vanes while being compatible with any type combustion chamber.
The present invention solves a problem existing with prior art vane retention constructions used in conjunction with annular combustion chambers. The construction disclosed herein permits retention of the first-stage nozzle vanes so that if one vane is burned out it will not pass through the turbine, while permitting individual removal and replacement of vanes in an engine that employs an annular type combustion chamber.
3,423,071 Patented Jan. 2l, 1969 ICC The present invention accomplishes the foregoing by using a retaining ring positioned and cooperating with the inner end of the stator vanes. No bolts or other locking means are used at the inner end of the vane; however, the retaining ring and cooperating vane projections on the vane ring are slidably positioned in a channel flange on an inner casing. The nozzle vanes are secured by locking means simultaneously to a removable ring and an outer casing. Therefore, once the removable ring has been detached, the entire vane assemblage is moved axially until the retaining ring and cooperating inner vane projections are free of the channel flange. Once clear, individual vanes can be removed and replaced.
Brie]c description of the drawing The figure is a fragmentary longitudinal sectional View taken through a gas turbine showing the device of the invention.
Description of the preferred embodiment As shown in the gure, hot combustion gases have annular combustion chamber 2 and impinge upon nozzle vane 4, nozzle vane 4 directing the gases into turbine blade 6. Nozzle vane 4, only one of a ring being illustrated, extends between outer casing 8 and inner casing 10.
Outer end 12 of vane 4 includes radially outwardly extending axially spaced flanges 14 and 16. Outer casing 8 includes radially inwardly extending axially spaced flanges 18 and 20, flanges '14 and 1-6 cooperating within and extending across the circumferential groove 19 between flanges 18 and 20. Flange 14, which is the upstream flange, has a plurality of apertures 22 and spaced outwardly from and in ange 18 is a plurality of apertures 24. In abutting relationship to flange 14 and flange 18 is removable ring 26, ring 26 having a plurality of openings 28 in axial alignment with aperture 22 and a second plurality of openings 30 in axial alignment with apertures 24. Locking means 32 passing through both sets of openings and apertures connects ring 26 to the outer vane flange 14 and outer casing flange 18.
Inner end 34 of vane 4 includes axially extending projections 36 and 38, projection 36 extending upstream and projection 38 extending downstream. Positioned in the axial space 40 between projections 36 and 38 and connected to inner end 34 is radially inwardly extending lug 42. Positioned around inner end 34 is retaining ring 44 which includes an L-shaped tab 46 anda radially outward extending tab 48. Tab 46 is the upstream tab on retaining ring 44 and cooperates with axial projection 36 to position and locate the upstream inner end of vane 4. Tab 48 and axial projection 38 are in substantially abutting relationship and together are positioned within channel opening 50 of flange 52 on inner casing 10. Tab 48 and axial projection 38 are slidably movable in and out of flange S2.
In order to remove vane 4 after an engine has been assembled, it is necessary to rst remove ring 26. The entire nozzle vane ring including retainer ring 44 is then free to move axially upstream. Once surface 54 on tab 48 clears surface 56 on channel ange 52, any individual vane 4 will .swing forward or upstream at the outer end 12 and then disengage from the nozzle ring as axial projection 36 passes surface 56.
1. A gas turbine including an annular combustion chamber, an outer casing, an inner casing, a plurality of vanes extending between the Casin-gs downstream of the combustion chamber, said vanes being arranged circumferentially about the engine axis, and a row of blades axially spaced downstream from said vanes, the improvement comprising:
the outer casing having a pair of axially spaced inwardly extending flanges;
a removable ring including a rst locking means for attachment to one of said flanges, said ring and the a plurality of vanes arranged in a circumferentially spaced annular series, the outer end of each of said vanes having a pair of axially spaced outwardly extending anges, the inner end of each of said vanes other ange forming a circumferential groove in 5 having an upstream directed substantially L-shaped which the outer end of the vanes are positioned and llange axially spaced from a downstream directed said ring having a second locking means for posisubstantially L-shaped flange; tioning the outer ends of each of said vanes axially a removable ring having means for attaching said ring and circumferentially; to the upstream outwardly extending ange on the a pair of axially extending projections on the inner end outer end of each of said vanes and means for atof each of said vanes; taching said ring to said outer casing; and an outwardly extending flange on the inner casing, said a retaining ring positioned peripherally of the inner flange defining a forwardly facing channel opening, end of the vanes, said ring having a substantially L- and shaped flange at its upstream end and defining a a retaining ring positioned peripherally of the inner ends rearwardly facing opening and spaced axially thereof the vanes, said ring having an outwardly extendfrom on outwardly extending tab, said upstream diing L-shaped tab defining a rearwardly facing opening rected L-shaped flange being positioned in said openand an outwardly extending tab axially spaced thereing and said downstream directed L-shaped flange from and forming a circumferential groove therebeand outwardly extending tab being substantially adtween in which the axial projections of each of said jacent, said tab and downstream flange being slidably vanes are positioned, the axial projections axially positioned in a forwardly facing flange opening on abutting the tabs on said retaining ring, the outwardly said inner casing. extending tab and the abutting axial projections be- 5. A construction as in claim 4 wherein: ing slidably positioned in said forwardly facing chaneach of said inner ends of said vanes has an inwardly nel opening, said retaining ring causing movement of projecting lug; and the entire vane assembly and permitting individual said retaining ring has a plurality of slots within which vane removal after the removable ring is detached, said lugs cooperate. the entire vane assemblage and retaining ring is moved 6. A construction as in claim 5 wherein: axially and the tab and projection is disengaged from the upstream end of each of said outer vane ends haS said channel opening. a plurality of apertures; 2. Aconstruction aS in claimlwhereint said removable ring has a plurality of openings in the upstream end of each of said outer vane ends has axial alignment with said apertures; and
plurality 0f apertures; said outer vane end is attached to said ring by locking the upstream inwardly projecting flange has a plurality means extending through said opening and said of apertures, spaced radially outwardly from the aperture. apertures in said outer vane ends; the removable ring has a plurality of inner openings in References Cited axial alignment with sfaid apertures in said outer vane UNITED STATES PATENTS end and a plurality o outer openings in axial alignment with said apertures in said radially inwardly 2,605997 8/1952 Lombard et al 253-78 projecting ange; and 2,628,067 2/1953 LOHll'Jald 253-78 locking means extending through both sets of axial 219371000 5/1960 Lfa'dV/lth "c 253-78 alioned openings and apertures 219841454 5/1961 Flon 253-78 g 3. A construction as in claim 1 wherein: 3,062,499 11/1962 Peterson 253-78 each of said inner ends of said vanes has an inwardly 3,075744 1/1963 Peterson 253-78 projectinglug; and 3,363,416 1/1968 Heybyrne et al. 253-78 3,365,173 l/l968 Lynch et al 253-78 said retaining ring has a plurality of slots within which said lugs cooperate. 4. A nozzle vane retaining apparatus for retaining the inner and outer ends of nozzle vanes in an inner and outer casing, respectively, comprising:
EVERETTE A. POWELL, IR., Pl'n'zm'y Examiner.