JP4384786B2 - Gas turbine backplate structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a structure of a back plate installed in a nozzle portion of a gas turbine.
[0002]
[Prior art]
FIG. 4 is a schematic cross-sectional view of a conventional gas turbine backplate structure 90. As shown in FIG. 4, in the conventional gas turbine, a nozzle 91 for discharging combustion gas is supported on a back plate structure 90 fixed to a housing 94, and the back plate structure 90 partitions a passage of combustion gas. A wall surface is formed.
[0003]
[Problems to be solved by the invention]
When heat is transferred from the combustion gas and the back plate structure 90 is thermally expanded, the position of the nozzle 91 changes. When the position of the nozzle 91 fluctuates, the position of the nozzle shroud 97 integral with the nozzle 91 with respect to the turbine 92 fluctuates. When a predetermined clearance (about 1 mm) between the nozzle shroud 97 and the turbine 92 fluctuates, the turbine output is changed. It will cause a decline.
[0004]
Therefore, conventionally, in order to avoid this, the elastic member 93 absorbs distortion due to thermal expansion, and the rigid member 96 is fixed to the housing 94 with a bolt 95 or the like, and a complicated structure that requires labor and cost is employed. Was. Therefore, an object of the present invention is to provide a back plate structure that can avoid a decrease in turbine output due to thermal expansion and can be easily formed.
[0005]
[Means for Solving the Problems]
In order to solve the above-mentioned problems, in the invention of claim 1, in a gas turbine that drives a turbine by discharging combustion gas from a nozzle, an annular nozzle mounting flange is provided on the nozzle, and the nozzle mounting flange is fixed to a housing, A gap is formed between the inner peripheral end of the nozzle mounting flange and the housing to form an annular groove, and the outer peripheral end of the back plate that forms a wall surface that partitions the passage of combustion gas at the annular groove portion in the radial direction. It was slidably held in the axial direction of the turbine shaft so that it could not move, and when the back plate expanded due to heat transfer from the combustion gas, the back plate was allowed to expand radially outward.
[0006]
In the invention of claim 2, in the invention of claim 1, the back plate is formed of sheet metal.
[0007]
Further, in the invention of claim 3, in the invention of claim 1 or claim 2, the inner peripheral end of the back plate can be slid in the radial direction with respect to the housing and cannot be moved in the axial direction of the turbine shaft. I tried to support it.
[0008]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a schematic cross-sectional view of a back plate structure 100 according to the first and second aspects of the present invention. In the back plate structure 100 of FIG. 1, the turbine 3 including the turbine blades 4 with respect to the housing 5 is supported by bearings (not shown).
[0009]
In addition, the annular nozzle mounting flange 8 fixed to the nozzle 2 is configured such that the annular fixing flange 16 and the annular fixing member 17 of the housing 5 are fixed with bolts and nuts (not shown) at equal intervals on the circumference. It is being fixed with respect to the housing 5 by.
[0010]
A nozzle shroud 6 is fixed to the nozzle 2, and the nozzle shroud 6 forms a wall surface that partitions the passage of the combustion gas, and a predetermined clearance (for example, 0... 0) is provided between the nozzle shroud 6 and the turbine blade 4. 5 to 1.0 mm).
[0011]
An annular groove 10 is formed between the housing 5 and the nozzle mounting flange 8. An outer peripheral end 1 a of the back plate 1 integrally formed in an annular shape is inserted into the annular groove 10, and the outer peripheral end 1 a of the back plate 1 is sandwiched between the housing 5 and the nozzle mounting flange 8. Further, the inner peripheral end 1 b of the back plate 1 is fixed to the housing 5 with bolts 7. The housing 5 is provided with screw holes 5a for screwing the bolts 7 at a plurality of positions (for example, eight positions) in the circumferential direction at equal intervals. In the annular groove 10 in which the outer peripheral end 1 a of the back plate 1 is inserted, a gap 11 is formed radially outward from the back plate 1.
[0012]
Since the annular back plate 1 has the outer peripheral end 1a and the inner peripheral end 1b fixed as described above, it cannot move in the axial direction of the rotating shaft 9 of the turbine 3, but heat is transferred from the combustion gas. When the thermal expansion occurs, the gap 11 is formed outward in the radial direction, so that the housing 5 and the nozzle mounting flange 8 can slide.
[0013]
The back plate 1 can be formed by pressing one sheet metal. Moreover, you may manufacture by die-casting.
[0014]
FIG. 3 is a partial sectional schematic view of the back plate structure 110 according to the invention of claim 1. The back plate structure 110 in FIG. 3 is different from the back plate structure 100 in FIG. 1 in that the back plate 1 includes an outer portion 12 and an inner portion 13. The outer peripheral end portion (not shown) of the outer portion 12 is sandwiched between the housing 5 and the nozzle mounting flange 8 similarly to the outer peripheral end portion 1a of the back plate 1 shown in FIG.
[0015]
Further, the inner peripheral end portion 13 a of the inner portion 13 is fixed to the housing 5 with bolts 7. The outer portion 12 and the inner portion 13 are integrally fixed by welding. In this way, the back plate 1 may be configured by integrally fixing the outer portion 12 and the inner portion 13 together.
[0016]
Further, the inner peripheral end portion of the inner portion 13 in FIG. 3 may be clamped by the clamping member 14 and the housing 5 as in an inner peripheral end portion 1b of the back plate 1 in FIG.
[0017]
FIG. 2 is a schematic cross-sectional view of the back plate structure 120 according to the invention of claim 3. The back plate structure 120 of FIG. 2 is different from the back plate structure 100 of FIG. 1 in that the inner peripheral end 1b of the back plate 1 is fixed, and there is no other difference from the back plate structure 100 of FIG. .
[0018]
As shown in FIG. 2, the annular clamping member 14 is fixed to the housing 5 by screwing bolts 7 into screw holes 5 a (only one is shown in FIG. 2) of the housing 5 arranged at equal intervals on the circumference. Has been.
[0019]
An annular groove 15 is formed between the clamping member 14 and the housing 5. The inner peripheral end 1 b of the back plate 1 is inserted into the annular groove 15, and the inner peripheral end 1 b is sandwiched between the housing 5 and the sandwiching member 14. Therefore, both the outer peripheral end 1 a and the inner peripheral end 1 b of the back plate 1 can slide in the radial direction, but cannot move in the axial direction of the rotary shaft 9.
[0020]
As described above, if the inner peripheral end 1b in addition to the outer peripheral end 1a of the back plate 1 is also slidable in the radial direction with respect to the housing 5, the back plate 1 is thermally expanded and deformed, and the passage of the combustion gas is formed. It is possible to more reliably avoid spreading and lowering the output of the turbine 3.
[0021]
【The invention's effect】
According to the first aspect of the present invention, the back plate 1 is sandwiched between the housing 5 and the nozzle 2 (nozzle mounting flange 8) and is slidable radially outward. 1 does not change relative to the housing 5 of the nozzle 2, and the clearance between the turbine blade 4 of the turbine 3 supported by the housing 5 and the nozzle shroud 6 does not change. A decrease in output can be avoided.
[0022]
According to the invention of claim 2, since the back plate 1 is formed of sheet metal, the manufacture becomes easy and the cost can be reduced.
[0023]
According to the invention of claim 3, in addition to the outer peripheral end 1a of the back plate 1, the inner peripheral end 1b is also slidable in the radial direction with respect to the housing 5, so that the back plate 1 is thermally expanded and deformed. Further, it is possible to more reliably avoid the combustion gas passage from expanding and the output of the turbine 3 from decreasing.
[Brief description of the drawings]
1 is a schematic cross-sectional view of a back plate structure according to the invention of claim 1;
2 is a schematic cross-sectional view of a back plate structure according to the invention of claim 3. FIG.
FIG. 3 is a schematic cross-sectional view showing another embodiment of the back plate structure of the invention of claim 1;
FIG. 4 is a schematic sectional view of a back plate structure of a conventional gas turbine.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Back plate 2 Nozzle 3 Turbine 4 Turbine blade 5 Housing 6 Nozzle shroud 7 Bolt 8 Nozzle mounting flange 9 Rotating shaft 10 Annular groove 11 Gap 14 Clamping member 100 Back plate structure

Claims (3)

In a gas turbine that drives a turbine by discharging combustion gas from a nozzle, an annular nozzle mounting flange is provided on the nozzle,
The nozzle mounting flange is fixed to the housing, a gap is formed between the inner peripheral end of the nozzle mounting flange and the housing to form an annular groove, and a wall that partitions the combustion gas passage at the annular groove portion is formed. The outer peripheral end of the plate is slidably slidable in the radial direction and immovable in the axial direction of the turbine shaft,
A back plate structure for a gas turbine, wherein when the back plate expands due to heat transfer from combustion gas, the back plate can expand radially outward. The back plate structure of the gas turbine according to claim 1, wherein the back plate is formed of a sheet metal. The back plate structure of the gas turbine according to claim 1 or 2, wherein an inner peripheral end portion of the back plate is supported so as to be slidable in a radial direction with respect to the housing and not movable in an axial direction of the turbine shaft.

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