RU2574106C2 - Fixed nozzle blade of steam turbine and membrane of steam turbine - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: fixed nozzle blade of steam turbine and membrane of steam turbine contains aerodynamic part, and internal and external side walls, each is made as single part together with one of side of aerodynamic part. Each side wall, internal and external, has discharge side with arc-like concave surface, passing along full length of the side wall, and suction side with arc-like convex surface passing along full length of the side wall. The arc-like concave surface of internal side wall and arc-line concave surface of external side wall amend respectively the convex surface of internal side wall and arc-like convex surface of external side wall. Another invention of the group relates to membrane of the steam turbine, containing external ring, internal ring, and ring structure out of fixed nozzle blades, located between the internal and external rings, and multiple pairs of removed connections. Each blade is made, as said above, at that at least one of said blades is secured with possibility of dismounting to the second of said blades. Each of removed connections secures with possibility of removal one of blades to each ring of membrane.

EFFECT: group of inventions simplifies the blade dismounting from the membrane of steam turbine.

8 cl, 7 dwg

Description

FIELD OF TECHNOLOGY

This invention relates to a nozzle assembly of a steam turbine or diaphragm. More specifically, this invention relates to a nozzle assembly of a steam turbine comprising a plurality of nozzle elements having arched or "conical" (eg, concave or convex) contact surfaces.

BACKGROUND OF THE INVENTION

Steam turbines contain fixed nozzle elements (or elements with an "aerodynamic profile") that direct the flow of working fluid to turbine blades attached to a rotating rotor. In patent document GB 918692 a nozzle element is described having an aerodynamic part which connects the upper and lower walls extending from it and made with it in one piece. The walls extend from the aerodynamic section in opposite directions, so that the blade has a Z-shape. A complete nozzle assembly is commonly referred to as the diaphragm of a steam turbine. One way to create a diaphragm design is to weld (or alternatively solder) a plurality of individual aerodynamic parts with integrated side walls (“fixed nozzle vanes” or “single elements”) to the inner and outer rings. Each of these single elements has contact surfaces to which adjacent single elements are welded or soldered (in the inner and outer ring). These contact surfaces have a front axial edge (or an edge on the “discharge side”) parallel to the axis of the steam turbine and a rear curved edge (or an edge on the “suction side”). Along with the fact that the modern design of such a single element, containing curved contact surfaces, provides a snug fit of the individual elements with each other, however, curved contact surfaces make it almost impossible to dismantle and repair the individual elements. So, for example, in the patent document US 4025229 described the diaphragm of a steam turbine containing an outer ring, an inner ring and an annular structure of fixed nozzle elements (blades) located between the inner and outer rings of the diaphragm. The blades are attached to the rings with welds, which are permanent and cannot be removed without damaging the blades and / or rings and without violating the integrity of the structure.

SUMMARY OF THE INVENTION

Turbine nozzle elements with tapered contact surfaces are offered. In one embodiment of the present invention, the stationary nozzle blade of a steam turbine comprises an aerodynamic part, an inner side wall made integrally with the first side of the aerodynamic part, an outer side wall made integrally with the second side of the aerodynamic part, each side wall, inner and outer has a discharge side with an arcuate concave surface extending essentially along the entire length of the side wall, and a suction side with an arcuate convex surface, flowing essentially along the entire length of the side wall.

A first aspect of the present invention provides a fixed nozzle blade of a steam turbine comprising an aerodynamic part, an inner side wall integrally formed with the first side of the aerodynamic part, and an outer side wall integrally formed with the second side of the aerodynamic part, each side wall inner and outer, has a discharge side with an arcuate concave surface extending essentially along the entire length of the side wall, and a suction side with an arcuate convex over a path extending essentially along the entire length of the side wall. In this case, the arcuate concave surface of the inner side wall and the arcuate concave surface of the outer side wall complement respectively the arcuate convex surface of the inner side wall and the arcuate convex surface of the outer side wall. This contributes to a simpler extraction of the blades in the axial direction without damaging adjacent blades and without violating the integrity of the structure in which they are installed.

The second aspect of the present invention provides a steam turbine diaphragm comprising an outer ring, an inner ring and an annular structure of fixed nozzle vanes located between the inner and outer rings of the diaphragm, each of these vanes comprising an aerodynamic part, an inner side wall integrally formed with the first side of the aerodynamic part, and the outer side wall made in one piece with the second side of the aerodynamic part, each side wall inside external and external, has a discharge side with an arcuate concave surface extending substantially along the entire length of the side wall, and a suction side with an arcuate convex surface extending substantially along the entire length of the side wall, wherein at least one of said the blades are removably attached to the second of these blades.

A third aspect of the invention provides a steam turbine diaphragm comprising an outer ring, an inner ring and an annular structure of fixed nozzle vanes located between the inner and outer rings of the diaphragm, each of these vanes comprising an aerodynamic part, an inner side wall integrally formed with the first side of the aerodynamic part, and the outer side wall made in one piece with the second side of the aerodynamic part, each side wall inside external and external, has a discharge side with an arcuate concave surface extending substantially along the entire length of the side wall, and a suction side with an arcuate convex surface extending substantially along the entire length of the side wall, wherein at least one of said the blades are attached with the possibility of dismantling to the second of these blades in the axial direction, and many welded joints that are made with the possibility of separation and each of which, essentially, is attached with the possibility of disconnecting one Well, from the indicated blades to the outer or inner ring of the diaphragm.

The attachment of the blade with the possibility of dismantling to the second, adjacent blade (for example, by holding it with friction or removable welded joints) and to the diaphragm rings (with the help of removable welded joints, such as tack welds) increases the reliability of fixing the blade in the structure while simplifying its removal without damaging the blades and / or diaphragm rings and without violating the integrity of the structure.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of the present invention will be more apparent from the following detailed description of its various aspects in combination with the accompanying drawings, which depict various embodiments of the present invention and in which:

figure 1 shows a top view of the nozzle assembly of a steam turbine;

 figure 2 shows a perspective view of a nozzle assembly of a steam turbine;

figure 3 shows a partial perspective view of the diaphragm of a steam turbine;

4 shows a perspective view of a fixed nozzle blade of a steam turbine in accordance with an embodiment;

5 and 6 show perspective views of a plurality of stationary nozzle blades of a steam turbine in accordance with embodiments;

7 shows a partial perspective view of the diaphragm of a steam turbine in accordance with an embodiment.

Note that the drawings of the present invention are not to scale. These drawings are intended to depict only typical aspects of the present invention and therefore should not be construed as limiting the scope of legal protection of this invention. In these drawings, the same reference numbers indicate the same elements.

DETAILED DESCRIPTION OF THE INVENTION

As indicated above, aspects of the present invention provide a nozzle element of a steam turbine with a tapered contact surface. More specifically, aspects of the present invention provide a nozzle assembly for a steam turbine comprising a plurality of nozzle elements with arched or "conical" (eg, concave or convex) contact surfaces. Said arched contact surfaces may allow individual nozzle elements to be removed and / or repaired while maintaining substantially the integrity of the nozzle assembly structure.

Turning to the drawings, where FIGS. 1 and 2 show a nozzle assembly 100 for a steam turbine (not shown). Figure 1 shows a top view of the assembly 100, while Figure 2 shows schematically the assembly 100 in a perspective view. The assembly 100 comprises a fixed nozzle vane 10 having at least one aerodynamic part 12 comprising an inner side wall 14 and an outer side wall 16. The assembly 100 further comprises an inner ring 18 and an outer ring 20. Under the words “inner” and “outer” in This document refers to the radial position relative to the rotor (not shown), to which the inner end of the aerodynamic part 12 is attached via the inner ring 18. The inner ring 18 and the inner side wall 14 (and similarly outwardly The e-ring 20 and the outer side wall 16) are connected together at the contact surface 80, which in this document refers to the entire area on which the rings and side wall are adjacent and connected to each other. The inner ring 18 and the inner side wall 14 (and similarly, the outer ring 20 and the outer side wall 16) are joined together by welding (or alternatively by soldering) at several points on the contact surface 80 (FIG. 1). It should be understood that, as set forth herein, soldering may be performed instead of welding. It is known in the art that welding and brazing can be used to join metals. It is also known that welding can be performed by metal alloying, usually with the addition of filler. In contrast to welding, soldering usually does not include melting of the base metals to be joined and, as a rule, is performed at a lower temperature. Despite the fact that metal joints are considered as “welded joints” in this document, it should be understood that these metal joints can be considered as “soldered joints” as an option.

In Fig. 1, multiple welding zones of the contact surface 80 both on the input (front) side of the aerodynamic part 12 and on the output (rear) side of the aerodynamic part, which are welded together, are generally shown as welds 90 in Fig. 1 and 2. Each contact surface 80 between the rings 18, 20 and the side walls 14, 16 may contain a mechanical radial stop 19, which maintains the aerodynamic part 12 in a proper radial position during welding and prevents shrinkage of the weld. Each contact surface 80 may further comprise a mechanical axial stop 17 which supports the aerodynamic part 12 in a proper axial position and adjusts the longitudinal depth of the weld. These mechanical stops 17, 19 have a connection consisting of a number of male stepped protrusions interacting with the corresponding female stepped protrusions of the complementary part, as will be described in more detail below.

In FIG. 3, the assembly 100 shown in FIG. 2 further comprises a plurality of fixed nozzle vanes 10 located in the diaphragm portion (the entire diaphragm is not shown for clarity of image). As shown in the drawing, the side walls 14, 16 of the blades 10 may have angled contact surfaces 34 (for example, a “sharply curved” contact surface containing two surfaces located at obtuse angles). These angled surfaces 34 make it possible to arrange the plurality of fixed nozzle vanes substantially flush with each other in the assembly 100. As shown in the drawing, the vanes 10 are held between the inner side wall 18 and the outer side wall 20 by a plurality of welds 90.

4 shows a fixed nozzle blade 110 of a steam turbine in accordance with an embodiment. The blade 110 may comprise an aerodynamic part 112, an inner side wall 114 and an outer side wall 116. As shown in the drawing, the inner side wall 114 may be integral with the first side of the aerodynamic part 112 (for example, may be machined from a forged blank or bar, welding, casting, soldering, etc.), and the outer side wall 116 may be integral with the second side of the aerodynamic part 112 (for example, can be performed by machining from forged th workpiece or bar, welding, casting, soldering, etc.). Each side wall 114 and 116, internal and external, may have a discharge side 124 and a suction side 126. The terms "discharge side" and "suction side" refer respectively to the discharge side and the suction side of the aerodynamic part 112. As is known in the art, the discharge side of the aerodynamic part 112 is a high pressure side designed to direct the flow of the working fluid through the blade 110 As is additionally known in the art, the suction side of the aerodynamic part 112 is a low pressure side substantially opposite one hundred discharge rons. Each discharge side 124 may have an arcuate concave surface 134, and each suction side 126 may have an arcuate convex surface 136. In one embodiment, the concave surface 134 may extend substantially along the entire length L of the side wall 114, 116, respectively, and the convex surface 136 may extend substantially along the entire length L of the side wall 114, 116, respectively. In one embodiment, the concave surface 134 of the inner side wall 114 has an arc radius substantially equal to the arc radius of the convex surface 136 of the inner side wall 114. In addition, in this embodiment, the concave surface 134 of the outer side wall 116 and the convex surface 136 of the outer side wall 116 may have a substantially equal arc radius. Additionally, in this embodiment, the concave surfaces 134 of the inner side wall 114 and the outer side wall 116, respectively, can have an arc length substantially equal to the arc length of the concave surfaces 136 of the inner side wall 114 and the outer side wall 116, respectively.

In accordance with FIG. 4, in one embodiment, the concave surface 134 of the inner side wall 114 and the concave surface 134 of the outer side wall 116 complement respectively the convex surface 136 of the inner side wall 114 and the convex surface 136 of the outer side wall 116. That is, in a device containing more one fixed nozzle blade 110 of the steam turbine (Fig.5 - 7), the convex surface 136 of the inner side wall 114 of the first blade 110 complements the concave surface 134 of the inner side wall 114 of a second similar atki 110. Similarly, the convex surface 136 of the outer sidewall 116 of the first steam turbine blade 110 complements the concave surface 134 of the outer sidewall 116 of the second blade 110 similar to the steam turbine. It should be understood that the term “complement” (complements) used in this document refers to the interaction of surfaces in which part of these surfaces can be essentially flush with each other. For example, in one embodiment, the surfaces on the discharge side (concave) and the surfaces on the suction side (convex) can be located in the diaphragm of the steam turbine (Fig. 7) so that each of the corresponding (inner, outer) concave surfaces of the first blade 110, essentially located at the same level with the corresponding (internal, external) convex surfaces of the second blade 110. The relationship between the surfaces on the discharge side and the surfaces on the suction side is further discussed with reference d in FIGS. 5 to 7.

Figures 5 and 6 show a structural configuration comprising a plurality of substantially identical fixed nozzle blades 110 of a steam turbine. In this configuration, the blades 110 can be arranged so that their complementary surfaces (concave surfaces 134 and convex surfaces 136, respectively) are substantially flush with each other. Such a solution can provide, inter alia, an efficient supply of steam to the aerodynamic parts 112 and mechanical strength. FIG. 6 shows a configuration comprising the steam turbine blades 110 shown in FIG. 5, together with additional substantially similar blades forming part of the diaphragm of the steam turbine (diaphragm rings not shown). As described with reference to FIG. 5 and more clearly shown in FIG. 6, a part of the diaphragm of a steam turbine can be made by placing the complementary conical surfaces of the blades 110 flush with each other. As will be described with reference to Fig.7, in a more complete diaphragm, the blades 110 can be attached to each other in the axial direction (indicated by the symbol "A") with the possibility of dismantling. The specified connection with the possibility of dismantling will allow you to remove in the axial direction one or more blades 110 from this site without significant violation of the structural integrity (for example, welded joints 190) of the remaining part of this site.

7 shows a portion of the diaphragm 200 of a steam turbine in accordance with an embodiment. Part of the diaphragm 200 may comprise a plurality of stationary nozzle blades 110 of the steam turbine arranged substantially so that the complementary surfaces are flush with each other, as described with reference to FIGS. 5-6. In addition, the part of the diaphragm 200 may comprise an inner ring 118 of the diaphragm and the outer ring 120 of the diaphragm, which can be essentially similar to the inner and outer rings (18 and 20) shown and described with reference to figures 1 to 3. In the completed diaphragm (not shown for clarity), the blades 110 may form a tseobraznuyu structure between the inner ring 118 and outer ring 120 of the diaphragm. With this arrangement, the blades 110 can be attached to each other with the possibility of dismantling. In addition, the blades 110 can be attached essentially, with the possibility of detaching to at least one of the inner ring 118 and the outer ring 120 of the diaphragm using removable welds 190. That is, if the blade 110 is not attached to at least one ring, inner 118 or outer 120, the blade 110 can be removed from the diaphragm 200 without destroying the welded joints 190 of one or more adjacent blades 110.

In the assembly 100 shown in FIG. 3, when fully assembled and welded (or alternatively soldered) to the ring-shaped design of the blades 10, individual blades 10 cannot be removed from the assembly 100 without removing a plurality of blades 10 (and their corresponding welded joints 90 or soldered joints ) This is because the angled contact surfaces 34 (FIG. 3) of the blades 10 prevent the adjacent blades 10 from moving even when the weld 90 is removed. More specifically, as shown in FIG. 3, the angled contact surfaces 34 of the blades 10 prevent the movement of these blades in the axial direction (A). In contrast, the blades 110 in the embodiment (for example, shown in Fig.7) are attached to each other with the possibility of dismantling. That is, each blade 110 that is not attached by welding to one ring, inner 118 or outer 120, can be removed or inserted between two fixed (for example, welding) blades 110 in the axial direction (A). In other words, in the diaphragm 200 of the steam turbine, each blade 110 can be axially mounted for dismounting to the adjacent blade 110. In addition, in one embodiment, each blade 110 is substantially removably attached to at least one ring, inner 118 or outer 120, with only a plurality of removable welds 190 (or alternatively solder joints).

A vane 110 having conical (concave, convex) contact surfaces, as set forth herein, may allow individual vanes 110 to be removed from the assembly (e.g., steam turbine diaphragm 200) by removing (e.g., mopping, machining and / or heating) only those welded joints 190 (or soldered joints) that are associated with a particular extractable blade. Such a solution may provide, inter alia, faster and more efficient repair, replacement and / or refinement of individual blades 110.

The terminology used in this document is used only to describe specific embodiments and is not intended to limit this description. It is understood that the singular forms used in this document also encompass the plural forms, unless the context clearly indicates otherwise. It should also be understood that the terms “contains” and / or “comprising” used in this description determine the presence of these properties, integers, steps, operations, parts and / or elements, but do not exclude the presence or addition of one or more other properties, whole numbers, steps, operations, parts, elements and / or combinations thereof.

In this description, examples are used that describe the invention, containing preferred embodiments, as well as enabling any person skilled in the art to practice the invention, including the creation and use of any devices or systems, as well as the implementation of any appropriate methods. The scope of legal protection of this invention is defined by the claims, while it may include other examples that are obvious to experts in this field of technology. It is understood that such other examples fall within the scope of legal protection of a given claims if they contain structural elements that do not differ from the elements described in the claims, or if they contain equivalent structural elements with insignificant differences from the elements described in the claims.

List of elements

10 Fixed nozzle blade

12 Aerodynamic part

14 Inner side wall

16 Outer side wall

17 Mechanical axial emphasis

18 Inner ring

19 Mechanical radial stop

20 outer ring

34 Angled

80 contact surface

90 Welded joints

100 Nozzle assembly

110 Fixed nozzle blade

112 Aerodynamic part

114 Inner side wall

116 Outer side wall

118 Inner aperture ring

120 Outer diaphragm ring

124 discharge side

126 Suction side

134 arcuate concave surface

136 Arched convex surface

190 Removable welds

200 diaphragm steam turbine

L Sidewall length

A Axial direction

Claims (8)

1. A fixed nozzle blade (110) of a steam turbine, comprising:
aerodynamic part (112),
the inner side wall (114), which is made in one piece with the first side of the aerodynamic part (112), and
the outer side wall (116), which is made in one piece with the second side of the aerodynamic part (112),
each side wall, internal and external, (114, 116) has a discharge side (124) with an arcuate concave surface (134) extending substantially along the entire length (L) of the side wall, and a suction side (126) with an arcuate a convex surface (136) extending substantially along the entire length (L) of the side wall,
wherein the arcuate concave surface (134) of the inner side wall (114) and the arcuate concave surface (134) of the outer side wall (116) complement respectively the arcuate convex surface (136) of the inner side wall (114) and the arcuate convex surface (136) of the outer side walls (116). 2. A fixed nozzle vane (110) according to claim 1, wherein the arcuate concave surface (134) of the inner side wall (114) and the arcuate convex surface (136) of this wall (114) have a substantially equal arc radius. 3. The fixed nozzle blade according to claim 2, wherein the arcuate concave surface (134) of the outer side wall (116) and the arcuate convex surface (136) of this wall (116) have a substantially equal arc radius. 4. The fixed nozzle blade (110) according to claim 1, wherein the arcuate concave surface (134) of the inner side wall (114) and the arcuate convex surface (136) of this wall (114) have a substantially equal arc length. 5. The fixed nozzle vane (110) according to claim 1, wherein the arcuate concave surface (134) of the outer side wall (116) and the arcuate convex surface (136) of this wall (116) have a substantially equal arc length. 6. The diaphragm (200) of a steam turbine, comprising:
outer ring (120),
inner ring (118),
an annular structure of fixed nozzle blades (110) located between the inner ring (118) of the diaphragm and the outer ring (120) of the diaphragm, each of these blades (110) containing: the aerodynamic part (112),
the inner side wall (114), made in one piece with the first side of the aerodynamic part (112), and
the outer side wall (116), made in one piece with the second side of the aerodynamic part (112),
wherein each side wall, inner and outer (114, 116), has a discharge side (124) with an arcuate concave surface (134) extending substantially along the entire length (L) of the side wall, and a suction side (126) with an arcuate a convex surface (136) extending substantially along the entire length (L) of the side wall,
moreover, at least one of these blades (110) is mounted with the possibility of dismantling to the second of these blades (110) in the axial direction (A), and
a plurality of pairs of removable compounds (190), each of which, with the possibility of extraction, attaches one of the said blades (110) to one ring of the diaphragm - external (120) or internal (118). 7. The diaphragm (200) according to claim 6, in which each pair of removable connections (190) essentially maintains an axial position of a removable fixed nozzle blade (110) that is removably attached. 8. The aperture (200) according to claim 6, wherein the arcuate concave surface (134) of the inner side wall (114) and the arcuate convex surface (136) of this wall (114) have a substantially equal arc length, and the arcuate concave surface (134) the outer side wall (116) and the arched convex surface (136) of this wall (116) have a substantially equal arc length.

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