WO1998004810A1

WO1998004810A1 - Turbine installation with pushing element and pushing element for a turbine installation

Info

Publication number: WO1998004810A1
Application number: PCT/DE1997/001546
Authority: WO
Inventors: Heinrich Oeynhausen; Axel Remberg
Original assignee: Siemens Aktiengesellschaft
Priority date: 1996-07-24
Filing date: 1997-07-22
Publication date: 1998-02-05
Also published as: ES2165623T3; EP0914543A1; JP2001508146A; DE19629933C1; ATE206502T1; PT914543E; CN1225705A; DE59704804D1; EP0914543B1; RU2185516C2; CN1091209C; JP3898229B2

Abstract

A turbine installation (1), in particular a steam turbine installation, has at least two partial turbines (2, 3a, 3b, 3c) having each a turbine rotor (5) which extends along a main axis (4) and an inner housing (7, 8a, 8b, 8c) that receives the guide blades (6). At least one inner housing (8a, 8b, 8c) can be moved in the axial direction, and a thermally expanding pushing element (9) is provided to ensure its axial displacement. The pushing element (9) has a first expanding component (10a) and a second expanding component (10b) joined by a coupling component (11). The coupling component (11) moves by mechanical and/or hydraulic means the second expanding component (10b) in the axial direction over a distance which is larger than the thermal expansion and/or axial displacement of the first expanding component (10a). Also disclosed is a pushing element (9).

Description

description

Turbine system with thrust element and thrust element

The invention relates to a turbine system, in particular a steam turbine system with at least two sub-turbines, each of which has a turbine runner extending along a main axis, the turbine runner being rigidly connected to one another. Each turbine section has an inner housing that accommodates the guide vise, at least one of the inner housings being displaceable in the axial direction. A thermally expanding thrust element is provided for an axial displacement of this inner housing. The invention further relates to a thrust element per se.

DE 35 22 916 AI describes a turbo set with at least one low-pressure partial turbine having an outer housing and an inner housing coaxial therewith and with at least one high-pressure and / or medium-pressure partial turbine arranged coaxially and upstream of the low-pressure partial turbine. The shafts of the partial turbines are rigidly coupled together to form a shaft train. Upstream of the low-pressure turbine section there is an axial bearing for the shaft train, which defines a reference plane from which the axial shaft expansion and displacement originate. The inner housing is connected by means of thrust-transmitting coupling rods to the axially movably mounted end of an axially adjacent partial turbine housing or to a turbine bearing housing. The coupling rods are led out through a wall of the outer housing by means of sealing elements which also allow limited transverse movement, in a heat-mobile and vacuum-tight manner. A turbine bearing upstream of the low-pressure part turbine defines a second reference plane, from which the axial expansion and displacement of the part-turbine housing supported on this turbine bearing and the one coupled to it

Part turbine housing take their exit. This results in an axial displacement of the shaft train and the partial turbo housing with practically the same axial expansion and in the same direction, with only minimal axial play between adjacent rotor and guide vane rings. The thrust transmission by means of the coupling rods is placed in the area of thrust-transmitting turbine bearings. In addition, a vacuum-tight bushing of the coupling rods is structurally combined with a horizontally heat-moveable claw bearing of the inner casing of the low-pressure turbine. The claw arms of the inner housing extend in the direction parallel to the shaft and lie on the supports of the associated bearing housing with slidable support and guide surfaces. The coupling rods are non-positively coupled to the claw arms in the area of the turbine bearings, in particular a membrane seal for a vacuum-tight bushing with an outer ring flange on an end face of the outer housing of the low-pressure turbine part and an inner ring flange on a part of the turbine bearing housing part is connected in a vacuum-tight manner. The arrangement of the sealing elements between the seating surfaces on the outer housing end wall and on the bearing housing, that is to say between parts of only slight relative displacement, means that the larger thermal displacements of the inner housing are decoupled from the sealing elements.

DE-AS 1 216 322 describes a steam or gas turbine with a plurality of partial turbines arranged coaxially one behind the other, the shafts of which are rigidly coupled to one another and at least one of whose housings is axially displaceable and is coupled to a stationary partial turbine housing or bearing block. The turbine low pressure housings each consist of an outer and an inner housing. The inner casing of the low-pressure turbine is coupled to an adjacent partial turbine casing or a bearing block by means of a linkage which is passed through the wall of the outer casing in a vapor-tight and heat-moving manner. The linkage can be a single rod which is sealed in the outer housing wall by an axially and radially flexible bellows. The linkage can continue to consist of three axially there are rows of hinged, hinged rods, the middle one of which is axially movable in a bushing with a sliding fit. Such a linkage should result in an axial displacement of the housing, by means of which the axial play between the rotor and the housing is kept as constant as possible. In order to change the size of the axial play, it is possible to change the length of the linkage by changing its temperature. This change in temperature is carried out by additional thermal stress on the boom using steam or a liquid.

Such a change in the size of the axial play, in which hot steam is passed through a tube, is described in GB-PS 1,145,612. An axially expandable tube is connected on each of its end faces to a rod, which in turn is fastened to the inner casing of a low-pressure turbine part. An axial displacement of the inner housing relative to a turbine runner is made up of the respective expansion of the inner housing, the expansion of the coupling rods and the expansion of the expansion tubes. The thermal expansion of the inner casings that are coupled to one another is defined starting from a fixed point which is arranged on the outer casing of the most upstream low-pressure sub-turbine. This starting point of the thermal expansions of the inner housing differs from the starting point of the thermal expansions of the rotor, which is defined in a bearing located further upstream. The expansion pipes are connected to the corresponding outer casings of the low-pressure turbine sections via respective compensators, so that the absolute expansion of the system consisting of the inner casing and coupling rods must be absorbed by the compensators. In order to ensure that the expansion of the turbine rotor and the system of inner housing and coupling rod are largely constant, steam must be fed to the expansion tubes in a predetermined manner. This steam must either be removed from the steam process or made available separately. be put. A control and monitoring system is also required, which, depending on the operating state of the steam turbines, feeds the steam to the expansion tubes to compensate for the axial play.

The object of the invention is to provide a turbine system in which an axial play between the rotor and the inner housing remains below a predeterminable value in a simple manner, in particular without complex control and monitoring systems. Another object of the invention is to provide a corresponding thrust element for reducing the axial play between the turbine rotor and the inner housing of a turbine system.

The object directed to a turbine system is achieved in that a thermally expanding thrust element is provided on an inner housing which is displaceable in the axial direction for axial displacement and which has a first expansion component and a second expansion component which are connected to one another via a coupling component. This coupling component mechanically and / or hydraulically effects an axial displacement of the second expansion component that is greater than an axial displacement and / or axial thermal expansion of the first expansion component.

The coupling element is preferably a mechanical lever. This lever can be rotated about a fixed point, the first expansion component and the second expansion component also being rotatably connected to the lever at a respective connection point. The distance between the second connection point and the fixed point is greater than the distance between the first connection point and the fixed point. A displacement of the first connection point caused by a thermal expansion and / or a displacement of the first expansion component thus causes the mechanical lever to rotate about its fixed point. Since the lever arm of the second expansion component, ie the distance between the second connection point and the fixed point, is larger than the lever arm of the first expansion component, the mechanical lever causes an axial displacement of the second expansion component, which is rectified and larger than the axial displacement of the first connection point.

In this way, in particular in the case of an arrangement of three low-pressure sub-turbines which are used for high performance at low cooling water temperatures in a steam turbine system, the relative expansion of the third low-pressure inner housing with respect to the turbine rotor is kept so low that between the stationary guide vanes and the rotating ones Blades even under full load of the steam turbine system the axial play remains below a predeterminable value. The axial play can be set to a value which essentially corresponds to the axial play of the other low-pressure sub-turbines by the choice of the corresponding rectified lever arms. This means that all low-pressure turbines can be designed identically.

Of course, it is possible to connect all the low-pressure partial turbines arranged one after the other in the axial direction via a thrust element with the simple articulation mechanism described. Through a suitable choice of the lever arms and thus a corresponding transmission ratio, axial movements can be generated for each of the low-pressure partial turbines, which reduce the relative expansion to the turbine rotor by a predeterminable value. In particular, the relative expansions can each be set to be constant. It is also possible to connect individual low-pressure turbines using rigid thrust elements without a mechanical or hydraulic displacement amplifier.

A coupling component that mechanically and / or hydraulically strengthens the axial displacement and / or axial expansion of the first expansion component in the same direction can be implemented in a structurally simple manner, requires no complicated monitoring and regulating device and Steam supply via additional lines. With such a coupling component, a reduction in the axial play between guide vanes and rotor blades of a turbine system is thus achieved with little constructional and operational expenditure, as a result of which the efficiency of the turbine system can be increased.

The thrust element, together with a support of a bearing supporting the inner housing, is preferably passed through a seal of an outer housing surrounding the inner housing. The seal preferably has a sealing bellows which can be expanded in the axial direction. With the joint implementation, there is a reduction in the number of openings in the outer housing and thus a structural simplification.

Preferably, an axial expansion joint, comprising the thrust element with a displacement amplifier (lever), an inner housing or a plurality of inner housings and optionally thrust elements without a displacement amplifier (coupling rods), and the interconnected turbine rotors have a common axial fixed point. In the case of an expansion joint consisting of the outer casing of a medium-pressure sub-turbine and the inner casing of two or more low-pressure sub-turbines, this axial fixed point is preferably a turbine bearing arranged in the axial direction in front of all the partial turbines and used to support the outer casing of the medium-pressure sub-turbine.

The task aimed at a thrust element for reducing different axial expansion between two components which can be expanded independently of one another along a main axis, in particular turbine rotor and inner housing of a turbine system, is achieved by a thrust element with a first expansion component, a second expansion component and a coupling component. The coupling component is preferably a mechanical lever which can be rotated about a fixed point and on which the first expansion component and the second expansion component are on the same Side of the lever are rotatably connected at a respective connection point. The second connection point is further apart from the fixed point than the first connection point. As a result, as a result of the leverage effect when the first connection point is displaced, the second connection point is amplified, which is thus displaced further in the axial direction than the first connection point. The thrust element can also have a hydraulic displacement amplifier, for example formed by a hydraulic channel tapering along the main axis, at the ends of which the first expansion component and the second expansion component are connected. A displacement of the first expansion component in the direction of the tapering of the hydraulic channel causes a displacement of an incompressible hydraulic fluid arranged therein into the tapering part. Due to the constant volume, the hydraulic fluid penetrates further into the tapered part than was displaced by the first expansion component. This results in an increase in displacement due to the incompressible hydraulic fluid.

A turbine system with a thrust element is explained in more detail using the exemplary embodiment shown in the drawing. Show it:

1 shows a longitudinal section through a steam turbine system, FIG. 2 shows a longitudinal section through a bearing between two low-pressure partial turbines with a thrust element, and FIG. 3 shows a plan view of the thrust element according to FIG. 2.

1 shows a steam turbine system 1 with a high-pressure sub-turbine 23, a medium-pressure sub-turbine 2 and three substantially identical low-pressure sub-turbines 3a, 3b, 3c arranged one behind the other along a main axis 4. The low-pressure sub-turbines 3a, 3b, 3c are connected to the medium-pressure sub-turbine 2 in terms of flow technology by means of a steam supply 24. The medium-pressure turbine section 2 has an external housing 22 on. Each low-pressure turbine part 3a, 3b, 3c has a respective inner housing 8a, 8b, 8c and an outer housing 14 surrounding the inner housing 8a, 8b, 8c. Each inner housing 8a, 8b, 8c carries the guide vanes 6 for low-pressure steam application. In each inner housing 8a, 8b, 8c there is a respective turbine rotor 5 which extends along the main axis 4 and which carries the low-pressure rotor blades 27. The medium-pressure turbine section 2 has an inner housing 7. A bearing 15 is arranged between the medium-pressure sub-turbine 2 and the first low-pressure sub-turbine 3a and between the respectively adjacent low-pressure sub-turbines 3a, 3b, 3c. This bearing 15 serves both to support the turbine runner 5 and the respective inner housing 8a, 8b, 8c. A bearing 15a is also provided between the high-pressure sub-turbine 23 and the medium-pressure sub-turbine 2 for mounting the turbine rotors of these sub-turbines 2, 23. In the area of the support of the inner housings 8a, 8b, 8c of the respective bearings 15, a coupling rod 9a is guided parallel to the main axis 4. A respective coupling rod 9a connects the medium-pressure turbine section 2 to the first low-pressure turbine section 3a and the mutually adjacent inner casings 8a, 8b, 8c of the low-pressure turbine sections 3a, 3b, 3c to one another. The outer housing 22, the inner housing 8a, 8b, 8c and the coupling rods 9a, 21 connecting them form an expansion joint which, when exposed to hot steam, extends axially in the direction of the main axis 4. This expansion joint thus formed has a fixed point 20, which is located on the bearing 15a between the high-pressure turbine section 23 and the medium-pressure turbine section 2. The size of the thermal expansion calculated from this fixed point 20 along the main axis 4 is represented by the expansion line 25. A corresponding expansion line 26 of the rigidly interconnected turbine rotors 5 of the medium-pressure sub-turbine 2 and the low-pressure sub-turbines 3a, 3b, 3c is also shown. By connecting the low-pressure part turbines 3a, 3b, 3c to form an expansion joint in combination with the outer housing 22 of the medium-pressure part turbine 2 the individual thermal expansions are used to shift the inner housings 8a, 8b, 8c in the direction of a generator (not shown) along the main axis 4. All thermal expansions of the inner housings 8a, 8b, 8c are thus added up along the main axis 4, as a result of which the relative expansion to the rigidly connected turbine rotors 5 is reduced. A comparison between the expansion lines 25 and 26 shows that there is still a difference in expansion over the entire length of the turbine system 1 between the turbine rotors 5 and the inner housing 8c of the last low-pressure sub-turbine 3c. This difference in expansion causes a different axial play between the guide blades 6 and the blades 27 of each low-pressure turbine part 3a, 3b, 3c.

By using a thrust element 9 shown in more detail in FIGS. 2 and 3 with an increase in the displacement of an inner housing 8a, 8b, 8c of a low-pressure partial turbine 3a, 3b, 3c, such an expansion difference can be reduced significantly by a predeterminable value. Such a thrust element 9 can be arranged as a replacement for a coupling rod 9a between the medium-pressure sub-turbine 2 and the first low-pressure sub-turbine 3a and between adjacent low-pressure sub-turbines 3a, 3b, 3c. It is preferably arranged between the last two low-pressure turbine sections 8b, 8c. The thrust element 9 has an essentially rod-shaped first expansion component 10a and a likewise essentially rod-shaped expansion component 10b. These expansion components 10a, 10b are connected to one another in an articulated manner via a coupling component 11. As can be seen in FIG. 3, the coupling component is a mechanical lever which can be rotated about a fixed point 12. At a respective connection point 13a, 13b, each of the expansion components 10a, 10b is rotatably connected to the expansion component 11 in the direction of the main axis 4 by means of pins (not shown). The connection point 13a is closer to the fixed point 12 than the connection point 13b. The connection point 13a lies between the connection point 13b and the fixed point 12, so that a displacement of the connection point 13a in the direction of the main axis 4 requires a greater displacement of the connection point 13b in the direction of the main axis 4. The expansion components 10a, 10b penetrate a respective bearing 15 and, together with a respective bearing area 28b, 28c, are guided through the respective outer housing 14 of the corresponding low-pressure partial turbine 3b, 3c. This procedure is carried out in a gastight manner by means of a respective seal 16, the seal 16 having a sealing bellows 18 which can be stretched in the direction of the main axis 4. The inner housing 8b, in which the expansion component 10a is screwed, rests on the support 28a. Correspondingly, the inner housing 8c rests on the support 28b, and the expansion component 10b is firmly screwed into a corresponding claw 17 of this inner housing 8c.

Depending on the position of the connection points 13a, 13b to the fixed point 12, the coupling component 11 can be used to set a corresponding displacement gain by a predeterminable value.

The coupling component 11 thus realizes a displacement amplification in a structurally simple and largely maintenance-free manner without a complex control, checking and pipe system, as would be necessary in the case of displacement amplification by means of a temperature increase due to steam.

The invention is characterized by a thrust element in a turbine system with a plurality of partial turbines, by means of which a displacement amplification is achieved mechanically and / or hydraulically. The thrust element preferably has a coupling component, which represents a mechanical lever, on the articulated two push rods with different, but on the same side lying with respect to a fixed point lever arms. A displacement amplification of the displacement of an inner casing of a partial turbine generated in the axial direction allows the axial play to be reduced between the blades of a turbine rotor and the guide blades of the inner casing. In addition to using essentially identical inner housings, this also means increasing the efficiency of the entire turbine system. The turbine system is preferably a steam turbine system with a high-pressure partial turbine, a medium-pressure partial turbine and two or more, in particular three, low-pressure partial turbines. Of course, such a thrust element is also suitable for reducing the axial play in a gas turbine system with several partial turbines.

Claims

claims

1. turbine system (1), in particular steam turbine system, with at least two partial turbines (2, 3a, 3b, 3c), each of which has a turbine runner (5) extending along a main axis (4), which turbine runner (5) are rigidly connected to one another, and an inner housing (8a, 8b, 8c) accommodating the guide vanes (6), at least one of the inner housings (8a, 8b, 8c) being displaceable in the axial direction and for an axial displacement of this inner housing (8a, 8b, 8c) Thermally expanding thrust element (9) is provided, characterized in that the thrust element (9) has a first expansion component (10a) and a second expansion component (10b), which are connected to one another via a coupling component (11), the coupling component ( 11) mechanically and / or hydraulically, an axial displacement of the second expansion component (10b) is greater than a thermal expansion and / or axial displacement of the first expansion component (10a) rkt.

2. Turbine system (1) according to claim 1, wherein the coupling element (11) is a mechanical lever rotatable about a fixed point (12), with which the first expansion component (10a) and the second expansion component (10b) at a respective connection point (13a, 13b) are rotatably connected, and the second connection point (13b) is further apart from the fixed point (12) than the first connection point (13a).

3. Turbine system (1) according to one of the preceding claims, in which at least one with the thrust element (9) connected partial turbine (3a, 3b, 3c) has an outer casing (14) surrounding the inner casing (8a, 8b, 8c), the Thrust element (9) and a support (28a, 28b) of a bearing (15) supporting the inner housing (8a, 8b) are guided together through a seal (16).

4. Turbine system (1) according to one of the preceding claims, in which an axial expansion composite comprising the thrust element (9) and the interconnected turbine rotors (5) have a common axial fixed point (20).

5. Turbine system (1) according to one of the preceding claims with a medium-pressure partial steam turbine (2) and at least two low-pressure partial steam turbines (3a, 3b) which are arranged along the main axis (4), the inner housing (8a, 8b) Low-pressure partial steam turbines (3a, 3b) are connected to the thrust element (9).

6. Turbine system (1) according to claim 5, in which the medium-pressure partial steam turbine (2) has an outer housing (22), which has a thrust connection (21) with the inner housing (8a) of the low-pressure partial steam turbine arranged downstream in the axial direction ( 3a) is connected, and a bearing (15a) connected to the outer housing (22) forms the axial fixed point (20) for axial thermal expansion.

7. thrust element (9) for reducing different axial expansions between two components that can be expanded independently of one another along a main axis (4), in particular turbine rotor (5) and inner housings (7, 8a, 8b, 8c) of a turbine system, with a first expansion component (10a) , a second expansion component (10b) and a coupling element (11), the coupling element (11) being a mechanical lever which can be rotated about a fixed point (12) and with which the first expansion component (10a) and the second expansion component (10b) of a respective connection point (13a, 13b) are rotatably connected, and the second connection point (13b) is further apart from the fixed point (12) than the first connection point (13a).