EP3165772A1 - Inner part for a turbomachine, turbomachine and method for mounting - Google Patents

Abstract

The invention relates to an inner part (IP) of a turbomachine (TCO) for arrangement in an outer housing (OC) of the turbomachine (TCO), the inner part (IP) having parts of a rotor (RO) provided for rotation in operation and elements of a stator (STA) formed as operating parts; wherein the rotor (RO) extends along an axis (X). In addition, the invention relates to a turbomachine with the inner part and a method for mounting the turbomachine. In the interest of a simplified and damage-free mounting, the invention proposes that the inner part (IP) is designed such that the rotor (RO) moves axially relative to the stator (STA) from a first axial position (AP1) to a second axial position (AP2). is wherein in the first axial position (AP1) at at least two axially spaced locations each extending in the circumferential direction (CD) support shoulder (SPS) respectively on the stator (STA) and on the rotor (RO) are each provided radially concentrically opposite, so the rotor (RO) and the stator (STA) can be supported radially relative to one another by means of the support shoulders (SPS), wherein the support shoulders (SPS) are designed such that in the second axial position (AP2) the support shoulders (SPS) of the rotor (RO) and the stator (STA) are not radially opposite one another.

Description

The invention relates to an inner part of a turbomachine for mounting in an outer casing of the turbomachine, the inner part having parts of a rotor provided for rotation in operation and elements of a stator formed as operating parts, the rotor extending along an axis. In addition, the invention relates to a turbomachine with the inner part and a method for mounting the turbomachine.

Turbo compressor and method of the type defined above are already in the patent application EP 2 045 472 A1 known. The method of assembling the turbomachine described in this patent application provides that an inner part of the turbomachine comprising the rotor and a stator as a finished assembled module is axially inserted into a circumferentially undivided outer casing. The insertion opening into the pot-shaped outer housing, which may also be referred to as a pot housing, is closed axially after reaching the end position of the inner part by means of a frontal lid.

In general, the axial end faces of the outer housing or frontal cover are each provided with a passage opening through which one shaft end of the rotor is axially led out of the outer housing. This shaft end can serve on the one hand for supporting the rotor and on the other hand for transmitting torques in front of or on the rotor of the turbomachine. In the region of the lead out of the shaft, a shaft seal is usually provided for sealing the gap between the opening contour and the shaft surface of the rotor or rotor.

As part of the assembly, the shaft end is used on an axial side of the attachment of a so-called horsetail, which can also be referred to as an extension. The horsetail is essentially an axial extension of the rotor at an axial shaft end. This extension is the support of the inner part against gravity in the phase of axial insertion into the cup-shaped outer housing, in which the inner part is already partially inserted into the outer housing, but the axial shaft end (without extension), which leads the insertion, not yet the axial frontal opening of the outer housing protrudes. In order to still intercept the inner part in terms of weight with respect to the outer housing, so that the inner part can be inserted without damage into the outer housing, this extension, which can be designed as a so-called horsetail (axially divisible) takes this vertically oriented load, so that the inner housing largely acting without friction normal force acting on the outer housing can be inserted axially. It is also conceivable that only a partial relief of the contact surface between the outer housing and the inner part takes place and the normal force between these two components by means of the horsetail is lowered only in the sense of a reduction in friction. The term "horsetail" results from the fact that this axial extension can be disassembled into axial sections. This extension serves to support the inner part until the leading end of the shaft exits axially from the opposite housing outlet or opening. After exiting the shaft or the runner can be caught directly.

A disadvantage of the known method is that a special effort must be made to support the stator relative to the rotor of the inner part, so that it does not come to uncontrolled contacts and power transmissions between the rotor and the stator. Is the inner part by means of the horsetail at least on one axial side indirectly over the rotor in its entirety at least on one side supported or raised, loads at least a part of the weight of the stator of the inner part on the points of the rotor, where it comes opposite the stator as a result of small game first to a contacting pad. As a rule, there is a large number of shaft seals in each turbomachine, which can be designed, for example, as labyrinth seals. Regardless of the respectively executed shaft seal type in the turbomachine, it is most likely to contact the contact area in the area of the shaft seals, because the radial clearances are the least executed in the interest of the lowest possible secondary flows. At the same time, the shaft seals in particular are components that are very sensitive, since, for example, in the case of the labyrinth seal, narrow sealing strips-or, in a two-dimensional view, sealing tips-are often used which are not suitable for transmitting large forces. Other components of the stator and the rotor are not designed to accommodate the large weight forces of each adjacent module in the rule. In order to avoid this uncontrolled partially punctiform at least line-shaped support between these heavy components of the inner part, a fixation in the radial direction between the rotor and the stator is usually provided, which is adapted to control the weight of the stator relative to the rotor controlled. These precautions are complex and sometimes cumbersome in the assembly. These precautions must be carried out, for example, that on the introductory movement leading side of the inner part of these precautions can be removed through the axially frontal opening of the outer housing. This need may require special precautions on the outer housing, which can be costly to manufacture and expensive to install and handle.

The invention has set itself the task, the cost and effort in the context of assembly for the purpose of supporting the stator relative to the rotor of the inner part of a turbomachine while not increasing the risk of damage.

To achieve the object of the invention, an inner part of the type defined above is proposed with the additional features of claim 1. In addition, the invention proposes a turbomachine and a method for assembling the turbomachine according to the respective claims. The respective dependent claims contain advantageous developments of the invention.

Information such as radial, axial or tangential or circumferential direction always relate to an axis of the rotor, which coincides with the axis of rotation of the rotor during operation, unless stated otherwise. Components with identical function and essentially identical design are identically denoted and in the exemplary embodiments generally identically referenced.

The inner part of a turbo-machine according to the terminology of the invention is a component which can generally include all parts of the rotor, but need not necessarily comprise. The inner part includes next to some of the rotor surrounded standing components, which are referred to here as a stator.

A preferred application of the invention relates to turbomachines designed as radial machines, in which a radial deflection takes place between the individual stages of the rotor in the stator. This radial deflection takes place by means of a circumferentially extending channel surrounding the rotor. These deflections are collectively referred to as return stages and usually include so-called intermediate floors, which are formed divided at least in an axially non-divisible rotor in the circumferential direction in a parting line. These intermediate floors arranged axially between the individual wheels of the rotor usually have shaft seals (the term "shaft seal" means in the context this document sealing elements of the stator and / or the rotor, such as a labyrinth seal, this term refers to the shaft seal as a whole, continuem means "shaft seal" sealing a gap between a rotor and a stator, not only on a housing outlet but possibly also on others Axial sections of the machine) that prevent flow of process fluid that is either compressed or expanded by the turbomachine toward lower pressure conditions. The quality of this shaft seal directly affects the extent of unwanted secondary flows, so that, for example, the radial clearance of this shaft seal is a primary factor influencing the efficiency of such a turbomachine.

In the case of an axially separable rotor, it is also possible not to form the return stages or intermediate floors in the circumferential direction and to gradually join together the stator with the rotor to form an inner part in a stacking working process.

The individual intermediate floors may be combined axially and radially by means of a shell divided over circumferentially in the circumferential direction or shared by adjacent intermediate floors, so that the stator of the inner part forms a unit which is firmly joined together and attached to one another. Alternatively, the individual intermediate floors may be fastened to one another in their part-joint plane by means of fastening elements and be combined axially relative to one another in another, if appropriate, manner. In any case, the inner part has an at least provisionally firmly assembled stator, so that the inner part forms a transportable unit for itself. The rotor is in this case in the inner part therefore arranged positively, because the wheels (this document uses the terms "impeller" and "wheels" synonym both individually and in compound terms) of the rotor in the return stages of the stator prevent an axial unlimited mobility.

Within the limits of the axial mobility, it is provided according to the invention that the stator is axially movable from a first axial position to a second axial position relative to the stator. In the first axial position, a support shoulder extending in the circumferential direction is respectively provided on the stator and on the rotor radially concentrically opposite at two axially spaced locations, so that the rotor and the stator can be supported radially relative to one another by means of this support shoulder. At least on the rotor, these support shoulders should be rotationally symmetrical, so that the support of the stator by means of the rotor relative to the weight of the stator is possible regardless of the circumferential position of the rotor. Particularly preferably, the support shoulder extends in the circumferential direction rotationally symmetric in the stator, so that, for example, a lifting of the entire inner part while attaching the stop means on the stator is possible, so that the rotor can be raised indirectly via the stator of the inner part.

Particularly preferably, the abutment shoulders on the rotor are each located on a hub-side wheel disc of an impeller. Here, the blades act on the wheel disc as stiffening ribs and prevent buckling of the wheel disc under the load.

Alternatively, the abutment shoulder can also be provided on a cover plate of the impeller, in which case the forces must be transferred from the weight of the stator via impeller blades between the wheel disc and the cover plate of the respective impeller. This must be taken into account when designing the blades.

Particularly preferably, the support shoulder is provided at each of the outermost radial end of the wheel disc or the cover plate, so that does not create a separate paragraph in example, the wheel disc additional axial space requirement.

The axial displaceability from the first axial position to the second axial position of the rotor relative to the stator of the inner part is expediently also made possible by an axially wider wheel side space, so that the wheel disk axially engages in the extended width of the Radseitenraums axial displacement, so that the Anlageschulter in the first axial position when engaged in the Radseitenraum wheel disc of the stator relative to the contact shoulder of the rotor is preferably located at the radially outer end of the wheel disc of the impeller. This procedure also has the advantage that in the case of a stepped cover labyrinth, this shaft seal provides sufficient axial play in the case of the wheel-disk-side displacement direction.

Particularly preferably, the wheel disc in the region of the abutment shoulder rotationally symmetrical - convex in cross-section - be formed so that it comes over a part of the circumference slight force-induced elastic deformations of the wheel or the stator in the region of the respective abutment shoulder to a substantially linear support. Line-shaped here means that the extent of the support surface is longer in the circumferential direction than in the axial direction. Alternatively, the abutment shoulder can also be rotationally symmetrical conical - in cross section obliquely to the axis or axis of rotation - each be formed, so that the two abutment shoulder surfaces are oriented parallel to each other in axially parallel alignment of the stator and the rotor. The cone bevel should in this case preferably be oriented such that the rotor is pressed against the stator with a pressure force perpendicular to the axis in the direction of an axial stop of the slope of the cone, so that an uncontrolled sliding of the abutment shoulders is excluded.

An advantageous development of the invention provides that the axial relative position of the stator and the rotor of the inner part can be fixed to each other by means of at least one fastening element. For this it is possible that the axial Relative position on an axial side by means of a securing element in a boundary region between the stator and the rotor, which is accessible from the outside, is fixed to at least one circumferential position by means of the securing element. For this purpose, for example, the rotor or the shaft of the rotor can be radially clamped by the fastening element, wherein the fastening element simultaneously contacts an axial reference surface of the stator, so that an axial movement is blocked at least unidirectionally, preferably bidirectionally, between the rotor and the stator. A complete backup of the axial position can also follow by means of two such fasteners.

Preferably, the axial end faces of the outer housing or frontal cover are each provided with a passage opening, through which in each case a shaft end of the rotor can be axially guided out of the outer housing. This shaft end can serve on the one hand for permanent or transitional mounting of the rotor and on the other hand for transmitting torques in front of or on the rotor of the turbomachine.

The inventive method provides that initially the outer housing is provided. Subsequently, an axial extension in the sense of the above-mentioned horsetail to the rotor at a shaft end is mounted rigidly so that the inner part raised by the extension - or intercepted in terms of weight - can be. Here it is sufficient if the inner part can be raised at least on one axial side. It is not necessary that the entire inner part can be raised as a free end of this axial extension. In any case, the connection between the extension and the shaft end must be rigid, so that the torques or bending moments arising from the transverse force can be transmitted to an axially spaced support of the extension. Subsequently, the inner part is inserted by means of the extension in the outer housing, wherein the rotor is located to the stator of the inner part in the first axial position. It is expedient here if the axial extension or the horsetail guides this insertion movement and is axially supported by a frontal axial opening of the outer housing of this extension, so that a normal force between the inner part and the outer housing is at least reduced during the insertion process. After complete insertion, the rotor can be offset axially relative to the stator of the inner part in the second axial position. This axial displacement of the rotor relative to the stator can take place with the aid of the horsetail, wherein the stator of the inner part in the outer housing, the rotor is relieved of the weight and the rotor can be maneuvered without this additional load in the second axial position.

Figur 1

einen schematischen Längsschnitt durch eine erfindungsgemäße Turbomaschine beim axialen Einführen des Innenteils in das Außengehäuse,

Figur 2

eine schematische Darstellung von Auflageschultern zwischen einem Rotor und einem Stator eines Innenteils in einem Längsschnitt an der Radscheibenseite,

Figur 3

ein Detail der Figur 2, dort mit III bezeichnet,

Figur 4

ein Ausschnitt aus der Figur 2, in dem der Rotor sich gegenüber dem Stator in einer zweiten Axialposition befindet,

Figuren 5 bis 7

jeweils eine schematische Darstellung von Schritten des erfindungsgemäßen Verfahrens zur Montage einer erfindungsgemäßen Turbomaschine mit einem erfindungsgemäßen Innenteil.

In the following the invention with reference to a specific embodiment with reference to drawings is described in detail. Show it:

FIG. 1

a schematic longitudinal section through a turbomachine according to the invention during the axial insertion of the inner part in the outer housing,

FIG. 2

a schematic representation of support shoulders between a rotor and a stator of an inner part in a longitudinal section on the Radscheibenseite,

FIG. 3

a detail of FIG. 2 , labeled III there,

FIG. 4

a section of the FIG. 2 in that the rotor is in a second axial position with respect to the stator,

FIGS. 5 to 7

in each case a schematic representation of steps of the method according to the invention for mounting a turbomachine according to the invention with an inner part according to the invention.

The figures each show longitudinal sections in a schematic representation, wherein the sectional plane extends along an axis X which is identical to the axis of rotation of a rotor RO. Geometrical data usually refer to axis X unless otherwise stated. The description of the figures applies across all figures, unless reference is made to a specific figure.

FIG. 1 shows a part of a turbomachine TCO with an inner part IP. The inner part IP is in FIG. 1 by means of an axial extension EXT mounted on a shaft end SHE of the rotor RO in an outer housing OC introduced in the axial direction. As well as in the FIGS. 6, 7 As can be seen, the inner part IP comprises parts of a rotor RO provided for rotation during operation of the turbo-machine TCO and elements of a stator STA designed as stationary parts during operation. The inner part IP is a transportable unit, which is preferably assembled at the point of commissioning of the turbomachine TCO with the outer housing OC. The outer housing OC is formed as a circumferentially undivided so-called pot housing. On at least one axial side of the outer housing is frontally provided with an axial opening, so that the inner part IP can be axially inserted into the outer housing OC. On the inner part IP, a cover COV is preferably pushed axially onto a shaft end SHE of the rotor RO and attached there, so that this cover COV is also positioned with the axial insertion of the inner part IP for the purpose of attachment to the outer housing OC. The rotor RO comprises a shaft SH and a plurality of impellers IMP or impeller shrunk onto the shaft. The stator STA comprises a plurality of return stages BST, which are provided between the individual impellers IMP designed as radial impellers and which each have a fluidic return channel which extends radially outward from the latter Impeller IMP deflected flow of a process fluid back to radially inward deflected. In a manner not shown, the return stages are equipped with aerodynamic guiding means, guide vanes for directing the flow of the process fluid. In one, as shown here, not axially dismountable, so built rotor, in which the wheels are shrunk onto a solid undivided shaft or otherwise secured, the return stages BST, which are also referred to as intermediate floors, provided with a parting line, which in a level which is substantially parallel to the axis X. To summarize the return stages BST is also provided with a parting line holder CR (this holder may also be referred to as an inner housing) is provided, the return stages BST in the desired axial and Secures radial position to each other. Alternatively, the return stages BST are attached directly to each other or attached, eg. screwed together.

The individual stages of the turbomachine TCO are sealed to one another by means of at least one shaft seal SSL. In the exemplary embodiment, the shaft seal seals SSL between a cover plate CW of the impeller IMP and the stator STA. The impeller IMP has, in addition to the cover plate on blades BL and a wheel HW. By means of the wheel disc HW, the impeller IMP is fixed to the shaft SH of the rotor RO with a shaft-hub connection. The attachment secures the impeller IMP in axial, radial and tangential (against twisting) direction.

The rotor RO is designed to be displaceable relative to the stator STA between a first axial position AP1 and a second axial position AP2. For this purpose, a corresponding Axialspielauslegung the shaft seals SSL is provided and the Radseitenräume WSR, which are fixed an axial clearance between the wheels IMP and the stator STA, are axially prepared accordingly. In the first axial position AP1 are located at two axially spaced locations (AL1, AL2) each extending in the circumferential direction CD Support shoulder SPS respectively on the stator STA and on the rotor RO each radially concentrically opposite, so that the rotor RO and the stator STA are supportable radially to each other by means of the support shoulders SPS. In the second axial position SPS of the rotor RO and the stator STA no longer radially opposite, so that a sufficient radial clearance for the operation taking into account the rotor dynamics of the turbomachine TCO is given. In the case of the bearing of the support shoulders SPS of the rotor RO and the stator STA together, the rotor RO is in its operation substantially concentric with respect to its axis of rotation, possibly somewhat eccentric, because it related a certain radial play between the support shoulders SPS of the stator STA and the rotor RO on the diameter there.

In the FIGS. 5, 6 and 7 In each case, steps of the method according to the invention for mounting the turbomachine TCO are reproduced. FIG. 5 shows the provision of the outer housing OC. FIG. 6 shows how in the context of step b) an extension EXT has been attached axially to a shaft end SHE of the rotor RO of the inner part IP. The inner part IP has already been partially inserted axially into the outer housing OC, wherein the axial extension EXT leads the insertion movement axially. Step d) is in the FIG. 7 shown schematically, wherein the Figures 3 . 4 show in their detailed reproduction the radial abutment of the abutment shoulders SPS against each other in the first axial position AP1 at the two axial points AL1, AL2. The FIG. 7 also shows that the cover COV of the outer housing OC is moved axially together with the inner part IP in its end position before it is fastened by means of fastening elements to the outer housing OC.

The shaft end SHE, which follows the axial movement, is held in the radial position by means of a support SUP '. In addition, or alternatively, the inner part can also be supported by the stator STA by means of a support SUP '. Because it becomes complex in heavier designs to absorb the torque from the weight force over the shaft, As a rule, the support via the inner part IP is then preferred.

Claims (6)

Inner part (IP) of a turbomachine (TCO) for arrangement in an outer casing (OC) of the turbomachine (TCO),
the inner part (IP) having parts of a rotor (RO) provided for rotation in operation and elements of a stator (STA) formed as operating parts, the rotor (RO) extending along an axis (X),
characterized in that
the inner part (IP) is formed such that the rotor (RO) is movable axially relative to the stator (STA) from a first axial position (AP1) to a second axial position (AP2),
wherein in the first axial position (AP1) at at least two axially spaced locations each extending in the circumferential direction (CD) support shoulder (SPS) respectively on the stator (STA) and on the rotor (RO) are each provided radially concentrically opposite, so the rotor (RO) and the stator (STA) can be supported radially relative to one another by means of the support shoulders (SPS), wherein the support shoulders (SPS) are designed such that in the second axial position (AP2) the support shoulders (SPS) of the rotor (RO ) and the stator (STA) are not radially opposite one another. Inner part (IP) according to claim 1,
wherein the radially opposite pairs of support shoulders (SPS) have at least one support shoulder (SPS), which is convexly spherical or conical. Inner part (IP) according to claim 1,
wherein at least one support shoulder (SPS) on the rotor on a hub-side wheel disc (HW) or a cover plate (CW) of an impeller (IMP) is formed. Turbomachine (TCO) with an inner part (IP) according to claim 1,
comprising the outer housing (OC). Turbomachine (TCO) according to claim 2,
wherein the outer housing (OC) in the circumferential direction undivided with a parting line (SP) substantially perpendicular to the axis (X) is designed as a pot housing. Method for assembling a turbomachine according to at least one of claims 4 or 5, characterized by the following steps: a) providing the outer housing (OC), b) attaching an axial extension (EXT) to the rotor (RO), which is rigidly attached to a shaft end (SHE), so that the inner part (IP) can be raised by means of the extension (EXT) against the weight, c) axial insertion of the inner part (IP) by means of the extension into the outer housing (OC), wherein the rotor (RO) to the stator (STA) is in the first axial position (AP1), d) Moving the rotor (RO) relative to the stator (STA) in the second axial position (AP2).

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