JPH04203424A - Blade surface inspection device for gas turbine - Google Patents

Abstract

PURPOSE:To facilitate inspection by hermetically closing an entrance hole with the head section of a bar-like cover, and thereby fitting the tip end of the bar- like cover slidably in an inspection hole in the longer direction of the bar-like cover for a turbine case via a seal ring. CONSTITUTION:A bar-like cover 62 is inserted into an entrance hole 50, it passes through a guide cylinder 54 and it passes through the through hole 56 of a bulkhead 41, so that a land section 64 is thereby fitted in an insertion hole 58 section in such a way as to be freely moved in the longer direction of the cover via a seal ring 66. The head section 63 of the bar-like cover 62 abuts against the upper end surface section around the entrance hole 50 via a packing 67, and it is detachably fixed onto a turbine casing 1 with a fastening bolt 68. When each surface of turbine blades is inspected, the bar-like cover 62 is pulled upward with the fastening bolt 68 removed. A bore-scope (not shown) is inserted into the entrance hole 50, let it pass through the inside of a guide cylinder 53, and also let it pass through a through hole 56, the insertion hole 58, an insertion hole 59 and an insertion hole 60 while being guided by the guide cylinder 53 so as to be inserted into a combustion gas passage S, so that each surface of the turbine blades is thereby inspected.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a Minoh inspection device for a gas turbine.

[Prior art] As a conventional wing surface inspection device, for example, the Japanese Utility Model Publication No. 1-1444
As shown in No. 36, a large inspection window hole is drilled in the outer circumferential wall of the turbine casing, and an insertion hole is formed in which a borescope can be inserted and supported in the turbine case around the turbine blade, and each hole is separately covered with a lid. It is installed.

In addition, both of the holes are formed at positions that avoid interference with the scroll chamber in the turbine casing.
Therefore, the borescope can be inserted into the turbine blade section by passing through the side of the scroll chamber.

As another conventional example, as shown in FIG.
There is a structure in which the outer circumferential wall of the turbine casing 1 is closed by the flange 72 of the lower member 73, and the insertion hole 58 of the turbine case 40 is closed by the flange 74 of the lower member 73. This mold assembly 70
In order to avoid the effects of thermal expansion, a spring 75 is compressed in the cylindrical portion 76 of the upper member 71 so as to be freely compressible in the longitudinal direction of the lid, thereby pressing the collar portion 74 against the upper end surface of the insertion hole 58 for sealing. ing. That is, the spring 75 absorbs thermal expansion and contraction.

[Problems to be Solved by the Invention] In the conventional structure of the former Utility Model Application Publication No. 1-144436, the lid for the inspection window hole in the turbine casing and the lid for the borescope insertion hole in the turbine case are independent from each other. Tightening and sealing must be done independently, which requires time and effort to attach and detach during inspection.

Furthermore, in order to ensure a visual confirmation space for the insertion hole of the turbine case, the opening area of the inspection window hole in the outer circumferential wall of the turbine casing must be increased, which reduces the rigidity of the turbine casing.

Furthermore, since it is necessary to locate the borescope insertion hole and the like while avoiding the scroll chamber, the borescope installation position is limited to the side of the small cross-sectional area of the scroll, and the degree of freedom in the installation position is small.

In the latter structure shown in FIG. 4, the number of parts of the mold assembly 70 itself is large, the structure is complicated, and it takes time and effort to attach and detach each member 71, 73. Further, the shape of the scroll is limited, and the positions where the fitting holes 58 and the like are formed are also greatly limited.

[Means for Solving the Problems] The invention as claimed in claim 1 provides a borescope formed in a turbine case so as to face a turbine blade portion, in order to simplify attachment/detachment work during inspection and improve sealing performance. An insertion hole;
A borescope inlet hole formed in the outer circumferential wall of the turbine casing that accommodates the scroll chamber, and a rod-shaped lid that is insertable from the inlet hole and extends to the fitting hole, and has a brim-shaped head. closes the inlet hole in a sealed state,
The tip of the rod-shaped lid is slidably fitted into the insertion hole of the turbine case in the longitudinal direction of the rod-shaped lid via a seal ring.

The invention as set forth in claim 2, in order to facilitate attachment and detachment work during inspection and expand the degree of freedom in setting the scroll shape, etc.
a borescope insertion hole formed in the turbine case so as to face the turbine blade portion; a borescope inlet hole formed in the outer peripheral wall of the turbine casing that houses the scroll chamber; and a borescope insertion hole that can be freely inserted from the inlet hole. The scroll chamber has a rod-shaped lid that extends up to It forms a small pore.

[Operation] During operation of the turbine, the borescope inlet hole in the outer circumferential wall of the turbine casing and the insertion hole in the turbine case are closed by a rod-shaped lid. That is, the borescope inlet hole on the turbine casing side is closed by the flange-shaped head of the rod-shaped lid, and the insertion hole of the turbine case is closed by the tip of the rod-shaped lid via a seal ring so as to be movable in the lid length direction.

Even if the rod-shaped lid undergoes thermal expansion and contraction, the sealing of the fitting hole portion can be maintained sufficiently.

When inspecting the turbine blade surface, simply remove the rod-shaped cover.
Since the borescope entrance hole and the borescope insertion hole can be opened at the same time, it is necessary to insert the borescope and inspect the container.

[Example] FIG. 1 is an enlarged vertical cross-sectional view of the main parts of a gas turbine in which the present invention is implemented. In FIG. The scroll chamber 3 is formed by the scroll chamber forming wall 2, and is fixedly supported by the support end wall 7 together with the heat shield 5. The combustion gas flow cross-sectional area of the scroll chamber 3 becomes narrower toward the discharge port 33 on the turbine main shaft side. The outer end of the scroll chamber 3 is connected to a combustor 9 via a combustion gas port 8 . The combustor 9 mixes compressed air and fuel from the compressor A and burns the mixture to generate a high temperature.

General purpose combustion gas is generated and supplied to the scroll chamber 3.

The discharge port 33 of the scroll chamber 3 opens parallel to the axial direction toward the combustion gas passage S, and the gas passage S includes various turbine blades, that is, first nozzles W (stationary blades) in order from the upstream side.
34, first turbine rotor IA30, second nozzle blade (stationary blade) 35, second turbine rotor blade 31, third nozzle IA
(Static W) 36, third turbine rotor blade 32, etc. are arranged in this order. Each turbine rotor g3o, 31.32 is fixed to the outer peripheral end of a blade supporting disk 20, 21.22, respectively. 21 and 22 are connected to each other via meshing portions 23 and 24 so that they can rotate together. Disk 20 of first turbine rotor blade 30
is further rotatably connected to a rotating body 25 via a meshing portion 26, and the rotating body 25 is connected to an impeller of the compressor A, and serves as a driving source for compressing air.

The disk 22 of the third turbine rotor blade 32 is further interlocked with the coupling 11 via the meshing part 19, and the coupling 11 is rotatably supported by the bearing housing body 15 via the bearing 12 and the bearing housing 13. Ru.

The turbine main shaft 10 extends to the left in FIG. 1 along the inner peripheral side of the disks 20.21.degree. 22, passes through the compressor A, etc., and is used as a power output shaft for driving a load such as a generator.

An exhaust diffuser 39 is disposed downstream of the third turbine rotor blade 32, and the combustion gas is decelerated within the exhaust diffuser 39.

Each nozzle! 35 and 36 are fixedly supported by a cylindrical turbine case 40 for supporting nozzles on the outer circumferential side thereof, and on the radially outer side of the turbine case 40 there is a cylindrical turbine case 40 where debris is scattered outside in the event that the turbine rotor breaks. A containment ring (cylindrical partition wall) 41 is arranged to prevent this.

In such a turbine, the blade surface inspection device according to the present invention is configured as follows.

A borescope insertion hole 60 is formed in the downstream portion of the radially outer cylindrical portion 35a of the second nozzle 835. A borescope inlet hole 50, through holes 51, 52, through holes 56,
A fitting hole 58 and a through hole 59 are formed.

The name tags 50, 51, 52, 56, 58, and 59 are lined up on the same radius line and the same center line as the borescope insertion hole 60.

A guide cylinder 53 that penetrates the scroll chamber 3 in the radial direction is inserted into a pair of through holes 51 and 52 of the scroll chamber forming wall 2, and one end of the guide cylinder 53 is connected to a portion of the through hole 51 on the radially outer side. The other end of the guide cylinder is fitted into a through hole 52 on the radially inner side so as to be movable in the length direction of the guide cylinder.

A plurality of small holes 54 for cooling the rod-shaped lid are formed in the middle of the guide tube 53.

The rod-shaped M62 for sealingly closing the inlet hole 50 and the insertion hole 58 has a length extending from the entrance hole 50 to the insertion hole 58 and the insertion hole 60, and has a hole at the upper end. A shaped head 63 is integrally provided, and a land portion 64 is integrally provided on the other end side, and an annular structure 65 is formed on the outer periphery of the land portion 64 as shown in FIG. A seal ring 66 is fitted into the annular structure 65.

In FIG. 1, the opening area of the inlet hole 50 is the same as that of the rod-shaped lid 62.
A large hole is not necessary as long as the hole can be inserted with plenty of room.

The rod-shaped lid 62 is inserted through the entrance hole 50, passes through the guide tube 54, passes through the through hole 56 of the partition wall 41, and enters the land portion 64.
is fitted into the fitting hole 58 via the seal ring 66 so as to be movable in the longitudinal direction of the lid.

The head 63 of the rod-shaped lid 62 is inserted into the artificial hole 5 through the packing 67.
0 and is removably fixed to the turbine casing 1 by fixing bolts 68.

In FIG. 3, which shows a sectional view taken along the line ■-■ in FIG. 5
3 is the downstream side of the scroll chamber 3, and is at an angle θ2 (approximately 3
0°).

When inspecting the turbine blade surface, the fixing bolt 68 is removed and the rod-shaped lid 62 is pulled upward. Then, a borescope (not shown) is inserted through the entrance hole 50, and the guide tube 53 is
The through hole 56, the insertion hole 58, the through hole 59, and the insertion hole 60 are guided by the guide cylinder 53.
is inserted into the combustion gas passage S, and each turbine blade surface is inspected.

During operation, compressed air outside the scroll chamber 3 passes through the guide tube 53 and the small hole 54 and is sucked into the scroll chamber 3, so the flow of the compressed air causes the outer periphery of the rod-shaped M62 and the guide tube 53 to be drawn into the scroll chamber 3. The inner periphery is cooled and shielded from the high pressure combustion gas within the scroll chamber 3. Therefore, the thermal expansion of the rod-shaped lid 62 can be suppressed to a small level.

Even if thermal expansion occurs, the land portion 64 is fitted into the fitting hole 58 so as to be movable in the lid length direction via the seal ring 66, so that the thermal expansion is absorbed while maintaining the sealing function sufficiently. be done.

Also, when inserting the borescope during inspection, since the inside of the guide tube 53 is cooled, the influence of heat on the borescope is reduced.

[Effects of the Invention] As explained above, according to the invention of claims 1 and 2 of the present application, one rod-shaped lid 62 connects the borescope fitting hole 58 formed in the turbine case 40 and the outer circumferential wall of the turbine casing 1. Since the borescope entrance hole 50 formed in the borescope is simultaneously closed in a sealed state, during inspection work, both holes 50 and 58 can be opened by simply removing one rod-shaped lid 62. Inspection work is easy.

In addition to the above effects, in the invention according to claim 1, the rod-shaped lid 62
The distal end of the cover is fitted into the inner peripheral surface of the borescope fitting hole 68 via the seal ring 66 so that the cover length can be moved freely. Thermal expansion and contraction of the rod-shaped lid 62 can be absorbed while maintaining sufficient performance.

In other words, the number of parts can be reduced.

In the invention as claimed in claim 2: (1) Since the scroll chamber 3 is supported through the guide tube 53 which is concentric with the borescope artificial hole 50 and the borescope insertion hole 58 and through which the borescope can pass, the turbine casing The borescope entrance hole 50 formed in the outer circumferential wall of 1 is sufficient to have the minimum diameter necessary for inserting the guide tube,
There is no fear that the rigidity of the turbine casing 1 will decrease.

(2) Also, by penetrating and supporting the guide tube 53 through which the borescope can pass through the scroll chamber 3, compared to the conventional case where the scroll chamber is formed to avoid interference with the rod-shaped lid, the rod-shaped The presence of the lid 62 does not restrict the shape or size of the scroll chamber 3, and the degree of freedom in setting the optimal position for forming the borescope insertion hole 58 increases.

(3) Since the guide cylinder 53 is formed with a small hole 54 for cooling, compressed air outside the scroll chamber 3 is
The scroll chamber 3 passes through the inside of the guide tube 53 and the small hole 54.
The flow of the compressed air cools the outer periphery of the rod-shaped lid 62 and the inner periphery of the guide cylinder 53, and shields them from the high-pressure combustion gas within the scroll chamber 3. Therefore, the rod-shaped lid 62
Thermal expansion can be kept small.

[Brief explanation of the drawing]

FIG. 1 is an enlarged cross-sectional view of a main part of a gas turbine to which the invention according to claims 1 and 2 of the present application is applied, FIG. 2 is an enlarged view of the U section in FIG. 1, and FIG. 3 is an enlarged view of - (2) Overall cross-sectional view, FIG. 4 is a vertical cross-sectional view of a conventional example. 1... Turbine casing, 3... Scroll chamber,
30.31.32...Turbine rotor blade, 34,35
゜36...Nozzle 1.50...Borescope inlet hole, 53...Guide cylinder, 58...Borescope insertion hole, 62...Bar-shaped lid, 63...Brim-shaped head, 66...
·Seal ring. Patent Applicant: Yanmar Diesel Co., Ltd. Agent Patent Attorney: Mr. Maeda (and 1 other person) Figure 2, i3, Figure 4

Claims (1)

[Scope of Claims] 1. A borescope insertion hole formed in the turbine case so as to face the turbine blade portion, a borescope inlet hole formed in the outer peripheral wall of the turbine casing that accommodates the scroll chamber, and the inlet hole a rod-like lid that can be freely inserted into the inlet hole, extends to the fitting hole, and has a brim-like head, the head of the rod-like lid sealingly closes the inlet hole; A blade surface inspection device for a gas turbine, characterized in that a rod-like lid of a case is fitted into a fitting hole so as to be slidable in the length direction. 2. A borescope insertion hole formed in the turbine case facing the turbine blade portion, a borescope inlet hole formed in the outer circumferential wall of the turbine casing that houses the scroll chamber, and a borescope inlet hole that can be freely inserted through the inlet hole and that fits into the borescope. A rod-shaped lid that extends to the insertion hole and has a brim-like head is provided, and the scroll chamber has a guide tube that is concentric with the inlet hole and the insertion hole and allows the borescope to pass therethrough, and is supported through the scroll chamber. A gas turbine blade surface inspection device characterized by having a small hole formed therein.