JP4940204B2 - Gas turbine stationary blade - Google Patents

Description

  The present invention relates to a gas turbine stationary blade having a cooling structure therein and a thermocouple for monitoring a wheel space temperature, and more particularly to a gas turbine stationary blade for improving the durability of a thermocouple protective tube for housing a thermocouple. Is.

  Gas turbines are widely used, including installation in combined cycle power plants. Since a gas turbine is exposed to high-temperature combustion gas during operation, a gas turbine provided with a cooling structure inside is generally used. In such a gas turbine stationary blade, it is important to perform a monitoring operation for confirming that the operation state of the high temperature portion of the turbine is normal.

  Thus, conventionally, a technique has been proposed in which a thermocouple is attached to a gas turbine stationary blade, and the ambient temperature in the vicinity of the turbine wheel, ie, the wheel space, which is a high-temperature part is measured and monitored using this thermocouple (for example, Patent Document 1, 2). Here, a conventional example of a gas turbine stationary blade provided with a thermocouple will be specifically described with reference to FIGS. 5 and 6.

  As shown in FIG. 5, the gas turbine stationary blade 1 is a hollow body in which cooling air flows, and a manifold 2 that holds the cooling air is installed therein. The gas turbine stationary blade 1 and the manifold 2 are made of a cobalt-based heat-resistant alloy material or the like.

  Since the thermocouple including the conducting wire is thin, it is accommodated in the thermocouple protection tube 3 in order to prevent damage due to external contact. The thermocouple protection tube 3 penetrates the gas turbine stationary blade 1 and the manifold 2, and the temperature sensing portion (tip portion) is installed in the inner ring of the gas turbine stationary blade 1. By using the thermocouple arranged in this way, it is possible to measure and monitor the atmospheric temperature of the wheel space between the inner ring of the turbine stationary blade 1 and the turbine wheel, and to grasp the operating state of the turbine high temperature section can do.

In addition, as a constituent material of the thermocouple protection tube 3, a material having a lower hardness than a material constituting the gas turbine stationary blade 1 or the like, specifically, a stainless steel material such as SUS304 is mainly used.
JP 2001-98905 A Japanese Patent Laid-Open No. 2004-28036

  By the way, in the gas turbine stationary blade 1, the thermocouple protection tube 3 is held by the outer ring of the stationary blade 1 from the turbine casing side and penetrates the manifold 2 to reach the inner ring of the gas turbine stationary blade 1. Therefore, a through hole 4 for inserting the thermocouple protection tube 3 is formed in the manifold 2. At this time, in order to maintain the cooling performance of the gas turbine stationary blade 1, the thermocouple protection tube 3 and the through hole 4 of the manifold 2 are welded or the like so that the cooling air inside the manifold 2 does not leak from the through hole 4. It may be possible to fix and seal.

  However, during operation of the gas turbine, both the manifold 2 and the thermocouple protective tube 3 are greatly deformed by heat, and because the constituent materials are different, the difference in thermal expansion is large. Therefore, fixing the thermocouple protection tube 3 to the through hole 4 of the manifold 2 is not preferable because excessive stress is generated in the fixed portion.

  Therefore, in practice, as shown in the enlarged view of FIG. 6 (A part of FIG. 5), a clearance is provided between the through hole 4 and the thermocouple protective tube 3, and no excessive stress is applied to both. It has a structure like this. However, it goes without saying that it is desirable to prevent air leakage from the manifold 2 as much as possible. Therefore, the gap between the inner wall surface of the through hole 4 and the outer peripheral surface of the thermocouple protective tube 3 is set as small as possible.

  However, as already described, since both the manifold 2 and the thermocouple protective tube 3 are largely thermally deformed, if the gap between the inner wall surface of the through hole 4 and the outer peripheral surface of the thermocouple protective tube 3 is small, vibration during operation of the gas turbine is caused. Therefore, they cannot deny that they are in contact with each other. In addition, since the thermocouple protection tube 3 is so-called cantilevered, the vibration associated with the gas turbine operation increases in amplitude as it approaches the end, and the outer periphery of the thermocouple protection tube 3 is stronger than the inner wall of the through hole 4. rub against.

  At this time, since the constituent material of the thermocouple protection tube 3 is lower in hardness than the constituent material of the manifold 2, thinning occurs due to wear. Therefore, when the thickness reduction proceeds and the thickness of the remaining thickness of the thermocouple protection tube 3 becomes a specified value or less, replacement is unavoidable. As a result, regarding the gas turbine stationary blade 1 main body, damage due to operation is still small, and even when repair or replacement is not necessary, repair for replacing the thermocouple protection tube 3 is necessary, which increases maintenance costs. Was invited.

  The gas turbine stationary blade 1 is frequently maintained from the viewpoint of ensuring reliability, and the maintenance cost is considerably high. Therefore, replacing the thermocouple protection tube 3 prior to repair or replacement of the gas turbine stationary blade 1 increases the burden of maintenance costs, which is a problem.

  The present invention has been proposed in view of the above circumstances, and its purpose is to extend the service life of the thermocouple protection tube by suppressing wear thinning that occurs in the thermocouple protection tube during gas turbine operation. An object of the present invention is to provide a gas turbine stationary blade that realizes reduction in maintenance cost and is excellent in economic efficiency and reliability.

  In order to achieve the above object, the present invention provides a gas turbine stationary blade provided with a thermocouple for measuring the ambient temperature in the vicinity of the turbine wheel, and the inside of the gas turbine stationary blade is internally cooled. In a gas turbine stationary blade provided with a manifold for holding a medium and a thermocouple protection tube for housing the thermocouple, a through hole is formed in the manifold, and the thermocouple protection tube is formed in the through hole. Is inserted in a portion of the outer peripheral surface of the thermocouple protection tube facing the inner wall surface of the through hole, a thick portion having a thickness in the radial direction of the thermocouple protection tube is provided. Whether the outer peripheral surface of the manifold is installed at a predetermined interval with respect to the inner wall surface of the through hole and is the same material as the thermocouple protective tube or a material whose hardness is smaller than the constituent material of the manifold. It is characterized in that it has been configured.

  In the present invention having the above-described configuration, since the thick portion of the thermocouple protection tube is in contact with the inner wall surface of the through hole of the manifold, even if they are rubbed due to thermal deformation and vibration accompanying gas turbine operation, The thinned portion is a thick portion whose hardness is smaller than that of the same material as the thermocouple protective tube or the constituent material of the manifold, and the thinning due to wear does not reach the thermocouple protective tube. Therefore, the service life of the thermocouple protection tube is extended, and it is not necessary to repair or replace the thermocouple protection tube at an earlier stage than the repair or replacement of the gas turbine stationary blade. As a result, an increase in maintenance cost can be suppressed.

  According to the gas turbine stationary blade of the present invention, a thick portion made of the same material as the thermocouple protection tube or a material whose hardness is smaller than the constituent material of the manifold is provided at a position facing the inner wall surface of the through hole of the manifold. This configuration prevents wear and thinning of the thermocouple protection tube due to friction with the manifold, prolongs the service life of the thermocouple protection tube, reduces maintenance costs, and improves economy and reliability. Can contribute.

(1) First Embodiment [Configuration]
Embodiments according to the present invention will be specifically described below with reference to the drawings. In addition, about the same member as the prior art shown in FIG.5 and FIG.6, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  First, a first embodiment according to the present invention will be described with reference to FIGS. FIG. 1 is a cross-sectional view of a main part of the first embodiment, and FIG. As shown in FIGS. 1 and 2, the outer surface of the thermocouple protection tube 3 facing the inner wall surface of the through hole 4 of the manifold 2 is formed as a thick portion having a thickness in the radial direction of the thermocouple protection tube 3. A cylindrical member 5 is attached.

  The outer cylinder member 5 is made of a stainless steel material such as SUS304 like the thermocouple protection tube 3, and this material has a hardness lower than that of the constituent material of the manifold 2. The thickness dimension of the outer cylinder member 5 is formed so as to be thicker than the expected amount of wear that occurs during the operation period between the periodic inspection and the latest next periodic inspection.

  Furthermore, the outer cylinder member 5 is a separate member from the thermocouple protection tube 3, and is composed of divided members 5a and 5b divided into two equal parts in the circumferential direction as shown in FIG. The outer cylinder member 5 is positioned with respect to the thermocouple protection tube 3 and then fixed to the thermocouple protection tube 3 by welding or the like. At this time, the outer peripheral surface of the outer cylinder member 5 is installed at a predetermined interval with respect to the inner wall surface of the through hole 4 of the manifold 2.

[Function and effect]
The operational effects of the first embodiment having the above-described configuration are as follows. That is, when the outer cylinder member 5 and the inner wall of the through hole 4 come into contact with each other due to thermal deformation and vibration associated with the gas turbine operation, the outer cylinder member 5 is made of a material softer than the constituent material of the manifold 2. The outer cylinder member 5 side, which is a thick part, is worn. Therefore, the frictional force does not reach the outer peripheral surface of the thermocouple protective tube 3, and the outer peripheral surface of the thermocouple protective tube 3 is not reduced by wear.

  Moreover, since the thickness dimension of the outer cylinder member 5 is made thicker than the expected amount of wear that occurs during the operation period between the periodic inspection and the next next periodic inspection, when carrying out the periodic inspection of the gas turbine, The outer cylinder member 5 is thicker than the depth at which the outer cylinder member 5 is thinned by the operation period during the inspection, and the thermocouple protection tube 3 does not contact the through hole 4 of the manifold 2.

  That is, as long as the periodic inspection is performed at an appropriate timing, the through hole 4 of the manifold 2 and the thermocouple protection tube 3 are not in contact with each other, and the thermocouple protection tube 3 may be thinned by the manifold 2 having a high hardness. There is no. Thereby, the thermocouple protection tube 3 can be continuously used without being repaired until the next periodic inspection.

  Further, since the member to be thinned is the outer cylindrical member 5, as long as it is replaced, the thermocouple protective tube 3 is basically not damaged. Therefore, the thermocouple protection tube 3 does not need to be replaced except for a failure, and the operation life of the thermocouple protection tube 3 is prolonged. As a result, maintenance costs can be significantly reduced and excellent reliability can be ensured.

  In addition, since the outer cylinder member 5 can be divided into two parts, that is, the divided members 5 a and 5 b, only the outer cylinder member 5 can be removed without removing the thermocouple protection tube 3 from the stationary blade 1. Further, when a new outer cylinder member 5 is attached, it can be attached to the thermocouple protection tube 3 from an arbitrary position without being fitted from the tip of the thermocouple protection tube 3. Thus, the outer cylinder member 5 is extremely easy to attach to and detach from the thermocouple protection tube 3, and can contribute to a reduction in maintenance costs.

  Further, since the outer peripheral surface of the outer cylinder member 5 has a predetermined interval with respect to the inner wall surface of the through hole 4 of the manifold 2, a clearance can be provided between the through hole 4 and the outer cylinder member 5. Therefore, excessive stress is not applied to the outer cylinder member 5 and the manifold 2 even during operation of the gas turbine, and high safety can be obtained.

(2) Second Embodiment [Configuration]
Subsequently, a first embodiment according to the present invention will be described with reference to FIGS. 3 and 4. FIG. 3 is a cross-sectional view of the main part of the third embodiment, and FIG. 4 is a cross-sectional view taken along the line II-II shown in FIG.

  In the first embodiment, the outer cylinder member 5 is mounted on the thermocouple protection tube 3, and the outer cylinder member 5 rubs against the through hole 4 of the manifold 2, whereas in the second embodiment, The cylindrical member 6 is fitted to the through hole 4 side of the manifold 2 and is characterized in that the inner wall portion of the cylindrical member 6 and the outer peripheral portion of the thermocouple protective tube 3 are rubbed with each other.

  At this time, the tubular member 6 is made of the same material as the thermocouple protection tube 3 or a material having a smaller hardness than the constituent material of the thermocouple protection tube 3 in order to suppress the thinning amount of the thermocouple protection tube 3. Further, on the outer peripheral surface of the thermocouple protection tube 3, a wear-resistant coating 3 a is applied to a portion facing the cylindrical member 6.

  Here, the configuration of the cylindrical member 6 will be described in more detail. That is, as shown in FIGS. 3 and 4, the cylindrical member 6 has a length dimension in which both end portions protrude from the through hole 4 in a state of being fitted into the through hole 4 of the manifold 2, and has a thickness in the radial direction. The dimension is set to be thicker than the expected amount of wear occurring during the operation period between the periodic inspection and the next periodic inspection.

  Moreover, the cylindrical member 6 is comprised from the division members 6a and 6b divided into 2 by the circumferential direction, and the penetration hole 6c is provided in the axial direction. The inner diameter dimension of the insertion hole 6c is larger than the outer diameter dimension of the thermocouple protection tube 3, and the thermocouple protection tube 3 is inserted therein at a predetermined interval. Furthermore, the R-shaped part 7 is installed in the both ends of the insertion hole 6c.

[Function and effect]
The operational effects of the second embodiment having the above-described configuration are as follows. That is, the outer peripheral surface of the thermocouple protection tube 3 comes into contact with the inner wall surface of the insertion hole 6c of the cylindrical member 6 due to thermal deformation and vibration accompanying the gas turbine operation. Since it is made of the same material as that of the constituent material or softer than the thermocouple protection tube 3, the cylindrical member 6 side is mainly worn. Moreover, since the outer peripheral surface of the thermocouple protection tube 3 is provided with the wear resistant coating 3a, the wear amount can be minimized.

  Further, the thickness dimension of the tubular member 6 is the same as that of the outer tubular member 5, and is thicker than the expected wear amount generated in the operation period between the periodic inspection and the next periodic inspection. When the operation is performed, the tubular member 6 is thicker than the depth at which the tubular member 6 is thinned by the operation period between two inspections.

  Therefore, as long as the periodic inspection is performed at an appropriate timing, the thermocouple protection tube 3 and the through hole 4 of the manifold 2 are not in direct contact, and the thermocouple protection tube 3 is thinned by the manifold 2 having a high hardness. There is no worry. As a result, as in the first embodiment, the thermocouple protection tube 3 can be used continuously without being repaired until the next periodic inspection. As a result, the operational life of the thermocouple protection tube 3 can be extended, which can contribute to reduction of maintenance costs and improvement of reliability.

  Furthermore, in the second embodiment, even if the tubular member 6 is thinned, it does not cause contact with the through hole 4 of the hard manifold 2 but is a softer thermocouple protection tube 3 that is softer than the manifold 2. Thinning is gentle because of wear due to contact with Therefore, in addition to the effect of extending the operational life of the thermocouple protection tube 3, the cylindrical member 6 that increases the durability of the thermocouple protection tube 3 is also compared with the outer cylinder member 5 that is in contact with the manifold 2. Thus, the lifetime can be extended.

  Further, the cylindrical member 6 can be divided into two divided members 6a and 6b, which can be easily removed from the through hole 4 of the manifold 2, and also when the new cylindrical member 6 is attached, Just plug it in. Therefore, the attachment and detachment work of the cylindrical member 6 is very easy, and can contribute to maintenance cost reduction.

  Moreover, since the inner wall surface of the cylindrical member 6 has a predetermined interval with respect to the outer peripheral surface of the thermocouple protection tube 3, excessive stress is not applied to the cylindrical member 6 and the thermocouple protection tube 3 even during gas turbine operation. It is possible to obtain high safety. Furthermore, since the R-shaped portions 7 are installed at both ends of the insertion hole 6 c, it is possible to prevent local wear thinning due to the thermocouple protection tube 3 coming into contact with the edge portion of the cylindrical member 6.

(3) Other Embodiments The present invention is not limited to the above-described embodiments, and the shape and material of each member can be selected as appropriate. For example, it is provided at both ends of the insertion hole 6c of the cylindrical member 6. The R-shaped portion may be a chamfered portion, and the installation position may be the end portion on the inner diameter side of the gas turbine stationary blade 1 instead of the both end portions of the insertion hole 6c. Moreover, the division | segmentation number at the time of dividing | segmenting the outer cylinder member 5 or the cylindrical member 6 into plurality can also be changed suitably. Furthermore, the embodiment which forms a thick part integrally with the thermocouple protection tube 3 is also included.

The principal part sectional view of the 1st embodiment of the present invention. Sectional drawing in the II cross section shown in FIG. Sectional drawing of the principal part of the 2nd Embodiment of this invention. Sectional drawing in the II-II cross section shown in FIG. Sectional drawing of the conventional gas turbine stationary blade. Detailed explanatory drawing of the A section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Gas turbine stationary blade 2 ... Manifold 3 ... Thermocouple protective tube 4 ... Through-hole 5 ... Outer cylinder member 5a, 5b, 6a, 6b ... Split member 6 ... Cylindrical member 6c ... Insertion hole 7 ... R shape part

Claims (8)

A gas turbine stationary blade in which a thermocouple for measuring an ambient temperature in the vicinity of the turbine wheel is installed, and a manifold for holding a cooling medium therein and the thermocouple are accommodated in the gas turbine stationary blade. In the gas turbine stationary blade provided with a thermocouple protection tube for
A through hole is formed in the manifold,
The thermocouple protective tube is inserted into the through hole,
In the portion facing the inner wall surface of the through hole on the outer peripheral surface of the thermocouple protection tube, a thick portion having a thickness in the radial direction of the thermocouple protection tube is provided,
The thick portion has an outer peripheral surface set at a predetermined interval with respect to the inner wall surface of the through hole of the manifold, and a material having the same hardness as the thermocouple protection tube or a material having a hardness smaller than that of the manifold. A gas turbine stationary blade comprising:   2. The gas turbine stationary blade according to claim 1, wherein the thick portion is formed so that a thickness dimension thereof is thicker than an expected wear amount generated during an operation period between periodic inspections.   3. The gas turbine stationary blade according to claim 1, wherein the thick portion is a separate member from the thermocouple protective tube and is configured to be divided in a circumferential direction. A gas turbine stationary blade in which a thermocouple for measuring an ambient temperature in the vicinity of the turbine wheel is installed, and a manifold for holding a cooling medium therein and the thermocouple are accommodated in the gas turbine stationary blade. In the gas turbine stationary blade provided with a thermocouple protection tube for
A through hole is formed in the manifold,
A cylindrical member is fitted to the through hole so that both ends protrude from the through hole,
The tubular member is formed with an insertion hole having an inner diameter larger than the outer diameter of the thermocouple protection tube,
The thermocouple protective tube is inserted into the insertion hole,
The gas turbine stationary blade according to claim 1, wherein the cylindrical member is made of the same material as the thermocouple protection tube or a material having a hardness lower than that of the constituent material of the thermocouple protection tube.   5. The gas turbine stationary blade according to claim 4, wherein the cylindrical member is formed so that a thickness dimension in a radial direction is thicker than an expected amount of wear occurring during an operation period between periodic inspections. .   6. The gas turbine static according to claim 4, wherein an R-shaped portion or a chamfered portion is formed at both ends of the insertion hole of the cylindrical member or an end of the gas turbine stationary blade inner diameter side. Wings.   The gas turbine stationary blade according to any one of claims 4 to 6, wherein the cylindrical member is configured to be divided in a circumferential direction.   The gas turbine stationary blade according to any one of claims 4 to 7, wherein a wear-resistant coating is applied to an outer peripheral surface of the thermocouple protection tube.

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