RU2631852C2 - Stationary blading for steam turbine, multistage steam turbine and method for manufacturing blade unit - Google Patents

Abstract

FIELD: machine engineering.

SUBSTANCE: stationary blading designed for the last stage of the steam turbine and containing guiding blade units which delimit the annular chamber and each of which contains an elongated blade portion. The mentioned elongated blade portion additionally has a longitudinal channel and an inner portion soldered to the first longitudinal end of the mentioned blade portion and having a through hole forming part of the annular chamber and an inner channel extending from the through hole to the longitudinal channel. The outer part which interacts with the mentioned steam turbine is soldered to the second longitudinal end of the mentioned blade portion. The outer part comprises an outer channel open to the surface of the mentioned steam turbine and to the mentioned longitudinal channel.

EFFECT: simplicity in maintenance or replacement, reliable operation in the presence of wet steam, the design is simple and easier to manufacture.

11 cl, 11 dwg

Description

FIELD OF TECHNOLOGY

This invention relates generally to steam turbines, and in particular to a guide vane intended for a steam turbine, as well as to a method for manufacturing a guide vane.

BACKGROUND OF THE INVENTION

A steam turbine is a turbomachine that converts thermal energy and steam pressure energy into rotational motion, which can be used to perform work. Steam turbines can be used, for example, to drive electric generators or compressors.

In order to improve the efficiency of a steam turbine, steam often undergoes expansion as it passes through a series of stages. Each stage usually comprises a diaphragm with guide vanes and a rotor assembly mounted on a bearing, comprising at least one impeller.

US 3881842 discloses a diaphragm for the last stage of a steam turbine containing welded hollow vanes. Each hollow blade has a groove for removing the liquid phase, with each groove communicating with the interior of the guide vanes. The inner space of the guide vanes communicates only with the annular channel of the rim and with the annular channel of the housing. The rim has openings configured to provide a connection between said channel and a capacitor.

When steam passes through the last stages of a steam turbine, sufficient energy can be absorbed from the steam to condense part of the steam and thus form the so-called wet steam. In addition to the possible corrosive effects, when the wet steam collides with the diaphragm and the guide vanes, this condensate tends to be intense impact on guide vanes and other parts of the diaphragm. As a result, guide vanes and other parts of each diaphragm located in the last stages of a steam turbine can be damaged, for example, by prolonged exposure to wet steam containing a high percentage of condensate.

For modern turbines, the manufacture of diaphragms with guide vanes is expensive, in particular for multi-stage steam turbines containing three or more stages, each of which may contain one or more separate diaphragms with guide vanes.

If the specified diaphragm is damaged, it may be necessary to stop the turbine and remove the damaged diaphragm for routine repair. If it is not possible to carry out the repair on site, it may be necessary to send the entire diaphragm for repair, or alternatively install a completely new stator diaphragm. In the worst case, if replacement is needed, it is necessary to manufacture a new diaphragm with guide vanes. Thus, in addition to the cost of the diaphragm, the costs associated with the long downtime of the steam turbine are added.

Accordingly, there is a need to replace a conventional diaphragm with one that is easy to maintain and / or replace, capable of trouble-free operation in the presence of wet steam, and whose design is simple and easier to manufacture.

SUMMARY OF THE INVENTION

In accordance with one illustrative embodiment, a guide vane for a steam turbine comprises guide vanes that define an annular chamber and each of which comprises a blade profile having a first body part and a second body part soldered to said first body part, and also a longitudinal channel and at least one hole passing through the specified first casing part, or the specified second casing part of the shell of the blade, or both of these casing parts to the specified longitudinal channel, an inner shelf soldered to the first longitudinal end of the specified profile part of the blade and having a through hole forming a part of the specified annular chamber, and an inner channel passing from the specified through hole to the specified longitudinal channel, and an outer shelf soldered to the second longitudinal end of the specified profile of the blade, interacting with the specified steam turbine and having an external channel facing the surface of the steam turbine and in the specified longitudinal th channel. In the guide vanes, the outer shelf may have a first groove configured to interact with a first protrusion on a specified surface of a steam turbine, and a second groove configured to interact with a second protrusion on a specified surface of a steam turbine. Said first groove and second groove may be offset relative to said inner shelf. A groove may be formed in said inner shelf of each blade, forming an annular groove in said guide blade rim, interacting with a metal ring to join said blades together. The specified annular groove may be facing inward to the center of the crown

According to another exemplary embodiment, the steam turbine comprises a rotor assembly comprising at least one impeller, a bearing attached to the rotor assembly and rotatably supported thereto, and a guide blade as described above.

According to another exemplary embodiment, the multi-stage steam turbine comprises a rotor assembly comprising at least one impeller, a bearing connected to the rotor assembly and rotatably supported, a guide vane, as indicated above, for the last stage of the steam turbines.

In accordance with another illustrative embodiment, a method of manufacturing a blade designed for a guide blade in the last stage of a steam turbine and containing a profile part of the blade, an inner shelf and an outer shelf, including soldering the first and second edges of the first body part of the profile part of the blade to the first and second the edges of the second body part of the profile part of the scapula with the formation of a longitudinal channel in the specified profile part of the scapula, making a through hole in the specified the inner shelf, the implementation of the inner channel in the specified inner shelf, passing from the surface of the inner shelf to the specified through hole, soldering the first longitudinal end of the profile of the blade to the specified surface of the inner shelf so that the specified longitudinal channel is open into the inner channel, the execution of the outer channel in the specified outer a shelf extending from the first surface to the second surface of the outer shelf, and soldering the second longitudinal end of the profile of the blade to the specified first the surface of the outer shelf so that the specified longitudinal channel is open to the specified outer channel.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and constitute a part of this specification, show one or more embodiments and explain these embodiments together with the description. In the drawings

FIG. 1 shows a steam turbine;

FIG. 2 shows a perspective view of an illustrative embodiment;

FIG. 3 shows a side view of an illustrative embodiment;

FIG. 4 shows a sectional view of the illustrative embodiment shown in FIG. 2;

FIG. 5-7 show the inside of the illustrative embodiment shown in FIG. 2;

FIG. 8-10 show the outer part of the illustrative embodiment shown in FIG. 2;

FIG. 11 is a flowchart of a method for manufacturing a blade assembly for a guide blade rim according to an illustrative embodiment.

DETAILED DESCRIPTION OF THE INVENTION

The following description of illustrative embodiments is given with reference to the accompanying drawings. The same reference numbers in the various drawings indicate the same or similar elements. The following detailed description does not limit the invention, the scope of legal protection of which is defined in the attached claims. A discussion of the following embodiments for simplicity is performed using terminology and design related to a turbomachine containing a stator and a rotor. However, further embodiments considered are not limited to these illustrative settings and can be used in other settings.

The reference in this description to “one embodiment” or “embodiment” means that a particular feature, structure or characteristic described in relation to an embodiment is included in at least one embodiment of the invention. Thus, the appearance of the wording “in one embodiment” or “in an embodiment” at various places in the description does not necessarily refer to the same embodiment. In addition, specific features, structures, or characteristics may be combined in any suitable manner in one or more embodiments.

To introduce the context necessary for understanding the following discussion of stator guide vanes according to these illustrative embodiments, FIG. 1 schematically shows a turbomachine in the form of a multi-stage steam turbine 400. In the drawing, the steam turbine 400 includes a housing (stator) 420, inside which several diaphragms 430 containing guide vanes are located, and a rotor shaft 450 provided with a number of impellers 440. The shaft 450 is radially supported and axial direction with bearings 480.

During operation, steam enters the steam turbine from the inlet 460, which passes through various expansion stages to the outlet 470 leading to the condenser. In each turbine stage, the steam is directed by the diaphragm 430 to the impeller 440, thereby converting thermal energy and steam pressure energy into rotational energy of the rotor shaft 450, which is used to perform work.

In FIG. 2 shows a portion of a guide vane 12 in accordance with an illustrative embodiment of the present invention. Said crown 12 comprises a group of individual guide vanes 14 extending around the rotor 28 (FIG. 3) in a steam turbine 10. FIG. 2 shows two such blades 14a and 14b.

Each blade 14a, 14b comprises a blade profile 16, as shown in FIG. 2 and FIG. 3. FIG. 4 shows a cross section of said profile portion 16 comprising a longitudinal stiffener 24 and longitudinal channels 26. As further shown in FIG. 4, the profile part 16 can also be made without a stiffening rib 24 and, accordingly, can have a single longitudinal channel 26. As will be described in more detail below, each specified part 16 is made by soldering the first case part 18 of the blade part to the second case part 22 the profile of the blade along the upstream edge 32 and the downstream edge 34 of the blade.

As further shown in FIG. 2-4, each profile part 16 has openings 36 in said part 22, or said part 24, or in both of these parts. In the embodiment shown in FIG. 2-4, each hole 36 is a groove made by electropulse processing. Alternatively, openings 36 may be made by other mechanical processing methods, for example by drilling or milling, or openings 36 may be made during the initial manufacture of said blade shell parts 22 and 24, for example, by means of an insert in a mold.

Each blade 14 comprises an inner flange 38 attached to the first longitudinal end of at least one profile portion 16, as shown in FIG. 2. In the embodiment shown in FIG. 2-4, the inner shelf 38 is soldered to the indicated part 16, as will be described further below. Each inner flange 38 has a through hole 42 extending across the longitudinal axis 46 (FIG. 3) of said portion 16. When each of these assemblies are installed in the steam turbine 10, the through hole 42 forms part of the annular chamber 20 in the guide vanes 12. between the through holes 42 in adjacent blades 14, at least one end of each through hole 42 may be provided with a groove 48 made to accommodate the gasket. In the embodiment shown in FIG. 2-4, the groove 48 is made to accommodate the o-ring.

Each inner shelf 38 also includes at least one inner channel 44, as shown in FIG. 3 extending from the through hole 42 to each longitudinal channel 26. Alternatively, if the stiffening rib 24 ends before the longitudinal end of the profile portion 16, then one inner channel 44 can be opened in both longitudinal channels 26.

Each blade 14 also comprises an outer shelf 52 connected to a second longitudinal end of at least one profile portion 16, as shown in FIG. 2 and 3. Each outer shelf 52 has at least one outer channel 54, which is open in each longitudinal channel 26 and to the inner surface of the steam turbine 10, as shown in FIG. 2, 9, and 10. Furthermore, in the embodiment shown in FIG. 2-4 and 8-10, each outer shelf may have a groove 74 on at least one side thereof. The groove 74 may be arranged to accommodate gaskets for sealing adjacent outer shelves 52 to each other and / or to create a damping effect on the guide vane 12. This crown 12 may be used in one of the last stages of the steam turbine 10, as shown in FIG. 2. During operation, condensate from the wet steam that collides with each blade 14 may enter the longitudinal channel 26 of the profile portion 16 through one of the openings 36. Several paths are available for the condensate to pass inside the blades 14 before it exits from the crown 12 into the place where the condensate is less likely to cause damage to the components of the steam turbine 10. The condensate can pass down in one path, which may contain vanes 14 located above the rotor shaft, through each longitudinal channel 26 and the inner channel 44 through hole 42. Open through holes 42 made in adjacent blades 14, which form an annular chamber 20 extending around a circumference in crown 12, allow said condensate to continuously pass downward by gravity. The condensate may exit the annular chamber 20 and continue to flow downward through the inner channel 44 of the vane 14 located below the rotor shaft of the steam turbine 10. And finally, the condensate may pass through the outer channel 54 to the surface of the steam turbine outside of the guide vane 12 .

In another path, condensate can enter the longitudinal channel 26 of the profile part 16 below the rotor shaft of the steam turbine 10 and exit through the external channel 54 without initial passage through the annular chamber 20 formed by the through holes 42.

Removing condensate from the wet steam passing through the last stages of the steam turbine 10 can prevent damage to the crown 12, as well as to the turbine blades 16 and other downstream components of the steam turbine 10. In addition, the crown 12 allows condensate to collect, which may contain residual heat, for use in other processes.

Some blade assemblies, for example, assemblies located above the rotor shaft of a steam turbine 10, can be made without an external channel 54, for example, to reduce production costs, since the condensate flow going down can eliminate the need for external channels 54 in the blades 14 located above the rotor shaft. In addition, some blades 14 can be made with profile parts 16 that do not have slots, for example, to further reduce production costs. Alternatively, as illustrated in the embodiments shown in FIG. 2-3 and 5-10, the blades 14 can be identical to each other. This circumstance provides a number of advantages. For example, the production process is becoming more unified. In addition, the maintenance of the steam turbine 10 is also more convenient, since during the repair or replacement of one blade 14, made in accordance with an illustrative embodiment, you will need only one part number, since all the blades 14 in the guide blade 12 are the same.

In addition to saving on the costs of diaphragm guides, which may require technical repair or replacement as a whole, the blades 14 are a simple one-piece design that is easier to install and / or replace than standard diaphragm blade guides. As shown in FIG. 2, 3 and 8-10, the outer flange 52 of each blade 14 interacts directly with the steam turbine 10. In particular, each outer flange 52 includes an upstream groove 56 and a downstream groove 58. The steam turbine 10 comprises an upstream protrusion 62 communicating with the groove 56 and the downstream protrusion 64, interacting with the groove 58. The groove 56 is offset closer to the inner part 38 compared to the groove 58. The offset between the grooves 56 and 58 may allow better matching between each blade and the desired vapor path through a steam turb Inu 10, and may also prevent the technician from unintentionally installing the blades 14 in an inappropriate position when assembling or maintaining the guide blade 12.

As shown in FIG. 2 and 3, the outer channel 54 is open to the surface of the steam turbine 10 between the protrusion 62 and the protrusion 64. Note that a chamber 76 is formed between the outer surface of the specified crown 12 and the surface of the steam turbine 10. The chamber 76 can facilitate the convenient collection of condensate that exits the outer channels 54.

In each inner shelf 38 there is a groove 66 forming a continuous annular groove facing the center of said crown 12, as shown in FIG. 2, 3 and 5-7. As shown in FIG. 3, each groove 66 interacts with a metal ring 68 that connects said vanes 14 together.

As seen in FIG. 2, 3 and 5-7, the inner shelf 38 of each blade 14 defines an inner solder pad surrounding the first longitudinal end of each profile portion 16. Also as seen in FIG. 2, 3, and 5-7, the outer shelf 52 of each assembly defines an external solder pad defining a second longitudinal end of each profile portion 16.

The solder pads provide a convenient surface for soldering the longitudinal ends of each profile part 16, and also limit the part of the stage and / or the steam path in the steam turbine 10. Note that from FIG. 2 and 3, it follows that the solder pad of each outer shelf 52 smoothly transitions to the surrounding surfaces of the steam turbine 10.

In the embodiment shown in FIG. 2-4, the body part 18 of the profile part of the blade can be attached to the body part 22 of the profile part of the blade by vacuum soldering. The first and second longitudinal ends of the resulting profile portion 16 can then be vacuum brazed to the inner flange 38 and the outer flange 52 of each blade 14. The equipment used for vacuum brazing of the diaphragm 12 may be standard vacuum brazing equipment, such as, for example discussed in US patent documents No. 4874918 and 4401254, the contents of which are incorporated herein by reference.

Thus, in accordance with the illustrative embodiment shown in FIG. 11, a method (1000) for manufacturing a blade intended for a guide blade and containing a blade profile, an inner shelf and an outer shelf, may include the following steps: soldering (1002) the first and second edges of the first case portion of the blade profile to the first and second edges the second body part of the profile part of the blade with the formation of a longitudinal channel in the profile part; making (1004) a through hole in the inner shelf; the implementation (1006) of the internal channel in the inner shelf passing from the surface of the inner shelf to the through hole; soldering (1008) the first longitudinal end of the profile portion to the surface of the inner shelf so that the longitudinal channel is open into the inner channel; the implementation (1010) of the outer channel in the outer shelf, passing from the first surface to the second surface of the outer shelf; and soldering (1012) the second longitudinal end of the profile portion to the first surface of the outer shelf so that the longitudinal channel is open to the outer channel.

The foregoing illustrative embodiments of the invention are intended to be illustrative in all respects, and not restrictive. Thus, this invention allows many changes in the detailed implementation, which can be extracted by a specialist from the description given in this document. It is intended that all such changes and modifications fall within the spirit and scope of the legal protection of the invention as defined in the following claims. No element, action or indication used in the description of the submitted application should not be construed as important or essential for this invention, unless expressly indicated. In addition, the term used in the singular may contain one or more elements.

Claims (27)

1. The guide vanes (12) for a steam turbine, containing guide vanes (14) that define the annular chamber and each of which contains a blade profile part (16) having a first case part (18) and a second case part (22) soldered to said first case part, as well as a longitudinal channel (26) and at least one hole (36) passing through said first a casing part (18), or said second casing part (22) of the blade shell, or both of these casing parts to the specified longitudinal channel (26), an inner shelf (38) soldered to the first longitudinal end of said blade profile (16) and having a through hole (42) forming a portion of said annular chamber (20) and an inner channel (44) extending from said through hole (42) to the specified longitudinal channel (26), and the outer shelf (52), soldered to the second longitudinal end of the specified profile part (16) of the blades, interacting with the specified steam turbine and having an external channel (54) that extends to the surface of the steam turbine and into the specified longitudinal channel (26). 2. The guide vanes according to claim 1, wherein said outer shelf (52) has a first groove (56) configured to interact with a first protrusion on said surface of a steam turbine, and a second groove (58) configured to interact with a second protrusion on the specified surface of the steam turbine. 3. The guide vanes according to claim 2, wherein said first groove (56) and second groove (58) are offset relative to said inner shelf (38). 4. The guide blade of the crown according to any one of paragraphs. 1-3, in which in the indicated inner flange (38) of each blade (14) there is a groove (66) forming an annular groove in the specified guide vanes, interacting with a metal ring (68) to join together these blades (14). 5. The guide vanes of claim 4, wherein said annular groove faces inwardly to the center of the crown. 6. Steam turbine containing a rotor assembly comprising at least one impeller, a bearing attached to the rotor assembly and designed to be rotatably supported, and guide vanes according to any one of paragraphs. 1-5. 7. A multi-stage steam turbine containing a rotor assembly comprising at least one impeller, a bearing attached to the rotor assembly and designed to be rotatably supported, guide vanes according to any one of paragraphs. 1-5, intended for the last stage of a steam turbine. 8. A multi-stage steam turbine according to claim 7, wherein a first groove (56) is made in the outer flange of each said blade, interacting with the first protrusion on the specified surface of the specified steam turbine. 9. A multi-stage steam turbine according to claim 8, wherein a second groove (58) is made in the outer flange of each said blade, interacting with a second protrusion on said surface of the specified steam turbine. 10. Multistage steam turbine according to any one of paragraphs. 7-9, in which the first groove is facing upstream of the working fluid, and the second groove is facing downstream of the medium inside said turbomachine. 11. A method of manufacturing a blade designed for a guide blade in the last stage of a steam turbine and containing the profile of the blade, the inner shelf and the outer shelf, including soldering the first and second edges of the first body part of the profile part of the blade to the first and second edges of the second body part of the profile part of the blade with the formation of a longitudinal channel in the specified profile part of the blade (1002), making a through hole in said inner shelf (1004), the implementation of the internal channel in the specified inner shelf passing from the surface of the inner shelf to the specified through hole (1006), soldering the first longitudinal end of the profile of the blade to the indicated surface of the inner shelf so that the specified longitudinal channel is open into the inner channel (1008), the implementation of the outer channel in the specified outer shelf, passing from the first surface to the second surface of the outer shelf (1010), and soldering the second longitudinal end of the profile part of the blade to the specified first surface of the outer shelf so that the specified longitudinal channel is open into the specified outer channel (1012).

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