CZ20002686A3 - Turbine nozzle stage having thermocouple guide tube - Google Patents

Abstract

The guide tube (46) is fastened near its opposing the ends in the outer casing (20) and in the inner casing (24) of the section (10) a jet stage. The guide tube (46) has an outer tube a cover (20) and an inner cover (24) having a serpentine shape; passes through the jet vane (16). The insert (42) is located in and is provided with openings (70, 72) for receiving the tubular portions of the guide tube (46). Cooling steam also through the chambers (56, 58) of the insert (42) on the opposite sides of the central chamber (64) of the insert (42) containing the guide tube (46). The opposite ends of the guide tube (46) are mounted in sleeves (70, 72) and further attached to the outer casing (20) and the inner casing (24).

Description

Turbine nozzle stage, thermocouple fitted with a guide tube for

Technical field

The invention relates to the field of turbines, for example ground gas turbines, provided with nozzle stages, and in particular it relates to a guide tube for a thermocouple wire passing through a nozzle stage blade comprising a thermal cooling medium.

BACKGROUND OF THE INVENTION

In turbines, especially ground gas turbines, it is desirable to monitor the temperature in the impeller spaces between the impellers and the partition walls. The thermocouple wires may pass through one of the jet vanes for the purpose of arranging the thermocouple sensing probe to measure the temperature in the impeller space. These thermocouple wires are typically housed in tubes to ensure the integrity of the wire throughout the life of the turbine.

However, in modern gas turbines, the thermal coolant flows through the nozzle vanes in different nozzle stages to cool the nozzle surfaces exposed to hot gases. The preferred cooling medium in one of such modern gas turbines is steam. This steam • ·

flows into the plenum between the outer casing and the outer belt of the jet stage, and then flows through the impingement plate for impingement cooling of the surfaces of the outer belt.

The spent impact steam flows through the holes in the blade extension and further flows radially inwardly of the blade.

Usually, the inserts are used in the cavity space of the nozzle vane into which the cooling steam flows, whereupon the cooling current passes through the holes in the inserts for the impingement cooling of the surfaces of the nozzle vanes ................... ....................

The spent impingement steam then flows radially inwardly into the plenum between the inner casing and the inner belt, then flows through the impingement holes in the impingement plate for impingement chiazenes ^; inner surface of the inner belt. The spent coolant is then returned through one of the cavities in the nozzle vane and through. outer belt and cover.

When using a thermal coolant such as steam, it is essential that the steam does not penetrate the areas of the impeller space or the hot gas path as well as the other areas within the turbine.

However, problems arise when the thermocouple wire is guided through a guide tube through a nozzle vane in which the thermal coolant is present. Due to the sensitivity to thermal differences between the thermocouple guide tube, such as a straight linearly running tube in which the thermocouple wire is housed and the rigid opposing ends of the thermocouple wire. »· · ·

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9 94 49 4 »44 of the thermocouple tube, this tube cannot accommodate the movement responsive to the thermal coolant. In addition, the tube must also be sealed to prevent coolant leaks.

SUMMARY OF THE INVENTION

In accordance with a preferred embodiment of the present invention, the non-rectilinear tube in which the wire of the thermocouple is accommodated passes through sleeves fastened and sealed in the outer housing and the inner housing. This tube is similarly fixed and sealed in the sleeves. In order to allow thermal expansion and contraction of the tube, the tube has a non-rectilinear shape, thereby bending between the outer casing and the inner casing. The tube preferably has a serpentine arrangement so that it can adapt to the heat

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In addition, the cavity in the nozzle vane through which the guide tube extends is provided with an insert to facilitate impingement cooling of the surface of the nozzle vane. In order to accommodate the thermoelectric cell guide tube and its thermal expansion and contraction within the cavity, the insert is provided with a pair of chambers near the suction and pressure sides of the blade. The inserts have through holes in the walls for impingement cooling of the suction and pressure surfaces of the nozzles.

The inner walls of the liner defining the chambers are spaced from each other and are preferably connected by a pair of side walls defining a central chamber in the liner. Preferably, the openings are elongated in the side walls for receiving the serpentine portions of the guide tube. Thus, the guide tube extends from the outer casing through the outer belt to the center chamber of the liner, further out through the opening in one wall of the center chamber, then returns to that center chamber through the opening in the opposite wall and returns to the center chamber. The tube then passes through the inner belt and inner cover.

According to a preferred embodiment of the present invention, the guide tube is attached to the inner housing and the outer housing. This is preferably done by fastening and sealing, for example by welding, the end portions of the tube in the sleeves, which are further fastened and sealed in the covers.

As a result, the serpentine arrangement of the guide tube facilitates the expansion and contraction of the guide tube in the nozzle vane space between the mounting sleeves, while preventing coolant leakage by sealing between the sleeve and the sleeves and between the sleeves and covers in the radial inner and outer end portions of the nozzle.

According to a preferred embodiment of the present invention there is provided a device for guiding a thermocouple over a fixed stage in a turbine having stages including a fixed stage nozzle section having an inner band and an outer band, a plurality of nozzle blades extending between said inner band and outer band, and a cover and an outer cover which respectively overlap said inner belt and the outer belt, comprising:

tube extending through said outer cover, said outer band and vane of said fixed • · it's the ·· ·· · ¹ such that • '♦ 9 9' · '·' · ^f 4 that '* it's a 9999 4 to 9 to 9 to 9 to 9 to 9 to 9 to 9 with this inner band and said tube.

a nozzle stage through said inner casing, the thermocouple wire in said tube extends indirectly through said nozzle vane and attached at its opposite ends to said outer casing and said inner casing, which tube responds to temperature fluctuations by expanding and contracting in space said nozzle vanes, while remaining fixed at its opposite ends to said outer housing and said inner housing.

The guide tube preferably has a serpentine arrangement in the space of the nozzle vane.

Preferably, the nozzle vane is provided with a cavity between said inner band and said outer band, wherein an insert for receiving and flowing a thermal cooling medium is disposed in the cavity, the insert having at least one through hole for receiving a portion of said tube.

Preferably, the liner is provided with a pair of chambers for receiving coolant and openings in the walls of said liner for flowing coolant from the chambers through these openings for impinging cooling the inner surfaces of said blade, said liner having a third chamber between said pair of chambers to receive said tube. said one through opening in the wall defining said third chamber for passing a portion of the tube through said opening.

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Preferably, the third chamber comprises a second wall and a second opening extending through said second wall for passing another portion of said tube.

Preferably, said apertures are radially spaced from one another and are elongated in the radial direction.

Preferably, the device according to the invention comprises a sleeve in an opening in at least one of said inner and outer covers forming a seal, said tube passing through said sleeve and being sealed therein.

Preferably, the device also includes a sleeve in an opening in both said inner housing and said outer housing, said sleeves being fixed and sealed in said guided inner housing in said outer housing, and wherein the tube has its end portions sealed within said sleeves.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will now be explained in more detail by way of examples of specific embodiments thereof, the description of which will be given with reference to the accompanying drawings, in which:

Fig. 1 is a plan view of a nozzle section showing the nozzle vane extension with the cover removed;

Fig. 2 is a partial cross-sectional axonometric view of a nozzle section where some components are removed, the view showing a thermoelectric • ft guide tube.

• · ftftft ft ft · 7 ί ft * ·· · ft ftft ftft ft ftftftft ft ftft ft • ft · ftftft ft · ft • ft ·· ft · ftft ft ft ft ftft ft • ftft ft ft ftft ft ftft ftft of the nozzle an embodiment of the present invention; in accordance with the preferred Fig. 3 is a view along line 3-3 of FIG. 2; in section, whereas the cut is made Fig. 4 is a view along line 4-4 of FIG. 2; in section, whereas the cut is made Fig. 5 is a view in section, whereas the cut is made

along line 5-5 of FIG. 2;

Fig. 6 is a side view of the insert passing through the nozzle vane cavity shown in Fig. 1;

Fig. 7 is an opposite side view of the insert passing through the nozzle vane cavity shown in Fig. 1; and Fig. 8 is a partial cross-sectional view of the insert showing the serpentine guide tube in the insert.

DETAILED DESCRIPTION OF THE INVENTION

Referring to FIG. 2, a nozzle section, generally designated 10, is shown to form one of a plurality of peripheral nozzle section circumferences about the turbine rotation axis. This nozzle section 10 comprises an outer belt 12, an inner belt 14 and a vane 16 lying between the outer belt 12 and the inner belt 14.

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It should be noted here that a plurality of vanes 16 are disposed about the rotor axis and lie in the hot gas path, the outer belt 12 and the inner belt 14 defining portions of the annular hot gas path in the turbine. The front hook 18 extends generally radially outwardly from the outer belt 12 for attachment to structural supports on the turbine frame (not shown) so that the nozzle sections 10 are attached about the turbine axis.

The nozzle section 10 forms part of an improved gas turbine, the nozzle stages being cooled by a thermal medium, which is preferably steam. As shown in Figure 2, the outer belt 12 is provided with a front cover (not shown) and a rear cover 20, the front and rear covers defining a plenum 22 between the outer strip 12 and these covers.

Similarly, the inner band 14, together with the inner housing 24, forms a positive pressure space 26 therebetween. The cooling steam thus flows through the inlet formed in the front cover into the positive pressure space 22. This positive pressure space 22 is also provided with an impact plate 28 having a plurality of apertures. for impingement cooling the outer belt 12.

The spent cooling steam then flows through the holes in the extension 30 and further flows through one or more cavities in the vane. For example, in Figure 1, five cavities 32, 34, 36, 38, and 40 are shown. Cooling steam is preferably supplied to the first, second, and fourth cavities, i.e. cavities 32, 34, and 38, while spent cooling steam is discharged. returning through the third cavity 36.

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Typically, air flows through the fifth cavity 40 for air cooling the trailing edge of the blade. Said cavities are provided with inserts 42, which will be described in more detail below, intended for impingement cooling of the surfaces of the vane.

The cooling steam flowing radially inward through the cavities exits into the internal plenum 26 and flows through the impingement plate 42 for impingement cooling the inner belt 14. The spent impingement cooling steam flows through the aperture in the extension of the vane cavities and then flows back through the cavity 36 into the steam return. Consequently, it should be emphasized that the cooling steam flows in the closed circuit through the nozzle sections.

It is very important that the cooling steam does not penetrate the impeller space, the hot gas path or any other part of the turbine. At the same time, however, it is desirable to provide a thermoelectric cell for monitoring the temperature in the space of the impeller. As a result, it has become necessary to guide the thermocouple over one of the nozzles through which the coolant flows.

As shown in Figure 2, the thermocouple is provided with a wire 44 disposed within a guide tube 46. The guide tube 46 extends between the outer housing 20 and the inner housing 24 and terminates in the temperature sensor 48 in the impeller space.

As shown in Figure 2, the guide tube 46 extends through the second cavity 34 of the vane 16. The guide tube 46 is fastened near its opposite end portions in the outer sleeve 50 and the inner sleeve 52.

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These sleeves 50 and 52 are further attached respectively to the outer cover 20 and the inner cover 24.

The attachment of the tube to the sleeves and the sleeves to the covers is preferably done in each case by welding, with a seal being provided at opposite ends of the guide tube to prevent steam from entering the cavity 34 behind the covers. However, since the guide tube is in a temperature-varying environment, this will lead to thermal expansion and contraction of the guide tube.

In order to accommodate the thermal expansion and contraction of the guide tube 46, the guide tube 46 is shaped so as to extend indirectly through the cavity 42 of the vane. Thus, as shown in Figures 2 and 8, the guide tube 46 has a serpentine shape that allows the guide tube 46 to expand and contract between its fixed end portions relative to the outer housing and the inner housing, and it could thus adapt to thermal differences.

The thermocouple tube is provided with inserts and must not extend into the chambers 56 and 58. The insert 42 in the cavity 34 is formed into two chambers 56 and 58. The walls 40 defining the chamber 56 are provided with holes for impingement cooling steam flow along the convex inner surface. wall blades.

Similarly, the walls 62 defining the chamber 513 are provided with openings along the surface area of the concave side of the vane for impingement cooling the convex vane wall. The chambers 56 and 58 are separated from each other by means of the central chamber 64;

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T »1 · * · * * · * 4 t ♦ 4 · defined by a pair of elongate radially facing walls 66 and 68.

As best shown in Figure 8, the wall 66 is provided with a radial elongate slot 70, while the wall 66 is provided with a radial elongate slot 72. The slots 70 and 72 are offset radially to each other to accommodate the serpentine sections of the guide tube 46. provided with an inner liner 74 and an inner liner 76 that open into the chambers 56 and 58 at opposite ends of the liner.

Consequently, as shown in Figures 2 and 8, the guide tube 46 passes through the opening 75 in the insert upper housing 74 into the central chamber 64. The serpentine guide tube 46 then exits the central chamber 64 through the opening 70 in the wall 66 and returns with the same opening 70 to the central chamber 64.

The guide tube then extends outwardly through aperture 72 and returns through the same aperture 72 to the central chamber 64 near the inner belt 14. Then, the guide tube passes through the lower housing for passage through the sleeve 52 and the inner housing 24.

Due to the serpentine shape of the guide tube, the guide tube is bent so as to accommodate thermal expansion and contraction between its end portions fixed in the sleeves 50 and 52 '. In addition, this bending does not in any way interfere with the insert or the walls of the blade, the insert walls being specially arranged to accommodate the bending movement.

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Although the present invention has been described in connection with an exemplary embodiment which is currently considered to be the most practical and advantageous, it is to be understood that the present invention is not limited to the embodiment described, but is intended to cover the entire embodiment. many modifications and equivalent arrangements are within the spirit and scope of the appended claims.

 Article Dřeš

Claims (6)

PATENT CLAIMS An apparatus for guiding a thermoelectric fixed stage in a turbine having stages including a fixed stage nozzle section having an inner belt (14) and an outer belt (12), a plurality of nozzle blades (16) lying between said inner belt (14) and the outer a strip (12), and an inner cover (24) and an outer cover (20), respectively, overlapping said inner strip (14) and the outer strip (12), comprising: a tube (46) passing through said outer cover (20), said outer band (12) and a jet blade (16) of said fixed nozzle stage, said inner band (14) and said inner cover (24), a thermocouple wire (44) in said tube, said tube extending indirectly through said nozzle blade and attached at its opposite ends to said outer shell and said inner shell, said tube responsive to temperature fluctuations such that it expands and contracts in the space of said nozzle vane while remaining fixed to its opposite ends to said outer cover and said inner cover. Device according to claim 1, characterized in that said tube has a serpentine arrangement in the space of the nozzle blade. 3. The apparatus of claim 1, wherein the nozzle blade is A> ·· a and a and a and a and a and a Aaa aaa aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa -aaaa -aaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa ) for receiving and flowing a thermal coolant, and wherein the insert (42) is provided with at least one through hole (70, 72) for receiving a portion of said tube. The apparatus of claim 3, wherein said liner is provided with a pair of chambers (56, 58) for receiving coolant and apertures in the walls of said liner for flowing coolant from the chambers through said apertures for impinging cooling the inner surfaces of said blade. said insert having a third chamber (64) between said pair of chambers for receiving said tube, said one through opening (70) in the wall (66) defining said third chamber for passage of a portion tube mentioned hole. 5. Equipment according to claim 4., v y z n and more c í s e t í m, that stated third chamber include e second wall (68) and a second opening (70), passing through said second wall (68) for passing another portion of said tube. 6. Apparatus according to claim 5, wherein said apertures are radially disposed relative to one another. 7. The apparatus of claim 1, characterized in that it is elongated in a radial direction. of claim 6, said holes being »» • »». * »; · -i r- t- S?, · * · · · ·· ti ti ti ti ti • those titi you - you the ones you • ti. ti ti the ones you ti ti ti · 8. Equipment according to claim 1, characterized with that contains the sleeve (50, 52) in the opening in at least one of the above internal and external a housing forming a seal, wherein said tube extends through said sleeve and is sealed therein. 9. Equipment according to claim 1, characterized by it means that it contains sleeve (50, 52) in the opening as in the above inner cover, so i in said external cover, wherein said sleeves are fastened and sealed in a guided inner housing in said outer housing, and wherein the tube has its end portions sealed in said sleeves.