DE102022130285A1 - Turbomachinery and processes - Google Patents

Abstract

The invention relates to a turbomachine (1) with a housing (2) and a rotor (3) which is mounted on the housing (2) with a first main bearing arrangement (5) and a second main bearing arrangement (6) so as to be rotatable about an axis of rotation (4) running in an axial direction (x). The first main bearing arrangement (5) has a first bearing surface (5a) formed on the rotor (3) and a first bearing device (5b) arranged on the housing (2) and interacting with the first bearing surface (5a). The second main bearing arrangement (6) has a second bearing surface (6a) formed on the rotor (3) and a second bearing device (6d) arranged on the housing (2) and interacting with the second bearing surface (6a). The rotor (3) comprises at least one turbo impeller (8b). According to the invention, the rotor (3) has at least one functional section (8) comprising the turbo impeller (8b), a first bearing section (11) detachably connected to the functional section (8), and a second bearing section (12) detachably connected to the functional section (8) and/or the first bearing section (11). The first bearing surface (5a) is arranged on the first bearing section (11) and the second bearing surface (6a) on the second bearing section (12).

Description

The invention relates to a turbomachine with a housing and a rotor mounted on the housing with a first main bearing arrangement and a second main bearing arrangement so as to be rotatable about an axis of rotation running in an axial direction. The first main bearing arrangement has a first bearing surface formed on the rotor and a first bearing device arranged on the housing and interacting with the first bearing surface. The second main bearing arrangement similarly has a second bearing surface formed on the rotor and a second bearing device arranged on the housing and interacting with the second bearing surface. The rotor also comprises at least one turbo impeller.

A turbomachine is a power machine that can convert the pressure and flow energy of a fluid (process fluid) into a rotary movement of the rotor - and/or vice versa. These are in particular turbo compressors, turbo pumps, expanders or turbines and the like. In order to enable the rotary movement of the rotor on the housing with as little friction and wear as possible, at least a first and a second main bearing arrangement are provided. This is designed to absorb the weight of the rotor as well as other static and dynamic forces that arise during regular operation of the turbomachine. These can also be caused, for example, by pressure differences in the process fluid along the rotor, by pressure and/or speed changes.

The higher the (intended) speed of the rotor on the housing, the more precise and effective the bearing must be. Uncontrolled contact between the rotor and the housing at speeds of several tens of thousands of revolutions per minute can lead to catastrophic failure and destruction of the turbomachine.

In addition to the design of the bearing, the shape of the turbo impeller is also essential for the manufacture of a turbo machine. The turbo impeller forms the flow-active part of the rotor, in which the mechanical interaction with the process fluid takes place. In order to optimize this interaction, the flow guidance devices arranged on it, such as guide vanes or flow channels, must be precisely shaped. The turbo impeller also makes up a significant proportion of the mass of the rotor. As a result, a particularly even mass distribution must be maintained to prevent imbalances. The surfaces of turbo impellers are also sometimes subsequently treated (in particular refined and/or coated) in order to reduce the friction of the process fluid and to reduce negative effects on the material of the rotor - for example due to corrosion. As a result, the manufacture of the turbo impeller is very complex and costly.

In order to withstand the high loads that occur and to ensure that a turbo impeller is positioned precisely, turbo impellers are often irreversibly connected to the rotor - for example by shrinking. Turbo impellers are also occasionally made from the solid material of the rotor. In any case, the disadvantage is that if just one component - for example a bearing - is damaged or if there is a subsequent change in the design of the turbo machine, the rotor must be completely replaced. This is very costly and resource-intensive.

Against this background, the invention is based on the task of making the use of turbomachines more flexible and more resource-efficient.

The subject matter of the invention and the solution to this problem is a turbomachine according to claim 1, an operating method according to claim 8, and a method for retrofitting a turbomachine according to claim 9. Preferred embodiments are specified in the dependent subclaims.

Based on the generic turbomachine, the invention provides that the rotor has at least one functional section comprising the turbo impeller, a first bearing section detachably connected to the functional section and a second bearing section detachably connected to the functional section and/or the first bearing section. The first bearing surface is arranged on the first bearing section and the second bearing surface on the second bearing section. The invention provides for a modular structure of the rotor. Both the first main bearing arrangement, the second main bearing arrangement and the functional arrangement with the turbo impeller are each manufactured separately as a module, which can be manufactured, maintained, repaired or replaced independently of the other components. This means that it is not necessary to manufacture a completely new turbo impeller if only one bearing device is damaged or needs to be replaced by a different bearing variant.

Within the scope of the invention, the functional section and/or the bearing sections can each be designed in several parts. However, it is preferably provided that the functional section, the first The bearing section and/or the second bearing section are each formed as one piece or in one piece - ie they are not assembled in a way that can be dismantled non-destructively.

The first bearing surface and the second bearing surface can be designed perpendicular to the axial direction and/or rotationally symmetrical about the axis of rotation without limiting the invention. Both the first bearing surface and the second bearing surface can be provided to absorb radial and/or axial forces. The first main bearing arrangement and the second main bearing arrangement can thus each be designed as an axial bearing, as a radial bearing or as a combined axial-radial bearing.

For example, a bearing surface can be designed in sections as the surface of a bearing disk, which serves as a component of an axial bearing. Alternatively or additionally, the bearing surface can also be designed - at least in places - as a cylindrically symmetrical outer surface of a shaft section, which serves to radially support the rotor.

The functional section can also be designed in one or more parts. In particular, the functional section can have a central shaft, in particular a hollow shaft, to which the bearing sections can be detachably connected. The at least one turbo impeller is designed or arranged on the shaft.

Without limiting the invention, the turbo impeller can be forged, milled from solid material or manufactured using additive manufacturing. The turbo impeller can also comprise a plurality of turbine blades which are attached to a carrier. This carrier can be formed as a separate component or as a section of a central shaft.

According to a preferred embodiment, the first main bearing arrangement is of a type selected from the group of fluid-lubricated bearings, magnetic bearings or gas bearings. These bearing types offer a reliable and efficient way of mounting the rotor of a turbomachine on the housing with low friction.

In the narrower sense, a fluid bearing is understood to be a liquid-lubricated bearing, particularly an oil-lubricated bearing. A bearing gap is formed between the bearing device and the bearing surface, into which a fluid is introduced as a lubricant. The support can be designed as a hydrostatic plain bearing, a hydrodynamic plain bearing or a hybrid form.

In a magnetic bearing, the bearing surface is at least partially made of a ferromagnetic or magnetizable or magnetized material. The bearing device comprises one or more controlled electromagnets, which exert forces on the bearing surface depending on the position and speed of movement of the rotor. This enables a contact-free and lubricant-free main bearing.

The application defines a gas-lubricated bearing as a fluid bearing in which a gaseous lubricant serves as support between the bearing device and the bearing surface. This can be air, the process fluid guided through the turbo impeller and/or an inert gas. In particular, a bearing of the type known as a "foil bearing" - also referred to as a "foil-air bearing" - can be used. This is a special form of hydrodynamic bearing in which a metal foil arrangement is positioned in the bearing gap near the bearing surface. This can include both smooth and structured, in particular wave-shaped, areas to optimize the flow properties.

According to a preferred embodiment, the second main bearing arrangement can alternatively or additionally be of a type selected from the group of fluid-lubricated bearings, magnetic bearings or gas bearings. The first main bearing arrangement and the second main bearing arrangement are particularly preferably of the same bearing type. This has the particular advantage of the two main bearing arrangements behaving in the same way during operation. In addition, synergy effects can be used, since the supply and control devices of the two main bearing arrangements can be designed together. For example, in the case of an oil-lubricated bearing, the two main bearing arrangements can share a common oil sump and a common oil pump. A common control and power supply is also possible with magnetic bearings.

According to a particularly preferred embodiment, the functional section is arranged in the axial direction between the first bearing section and the second bearing section. The two bearing sections do not touch each other directly and are only indirectly connected to each other via the functional section. The arrangement of the bearing sections on both sides makes it easier to absorb bearing forces. This makes it easier to absorb tilting moments and centrifugal forces of the turbo impeller and to introduce them into the housing.

Preferably, the rotor is completely supported on the housing by the first main bearing arrangement and the second main bearing arrangement (in the axial direction and radial direction). No further bearings are required for operation. Even if these can provide radial and/or axial support to a certain extent, mechanical connections for driving or driving the turbomachine are not to be understood as "bearings" in the sense of the invention. For example, a drive or driven shaft connected axially to the rotor at the end or a pinion formed on the rotor that meshes with a gear are not bearings in the narrow sense.

The turbo arrangement can also contain safety bearings that are not effective during normal operation. These serve as a backup in particular when starting up or shutting down the turbo machine and/or in the event of a sudden failure of the main bearing arrangements in order to prevent damage to the turbo machine. The safety bearings can in particular be designed as rolling bearings, in particular needle bearings, which have no contact with the rotor during normal operation, since the main bearing arrangements keep it at a corresponding distance.

According to a particularly preferred embodiment, the first bearing section and the second bearing section do not have a turbo impeller, in particular no flow-active parts directly attached to them. With a larger number of bearing sections, this particularly preferably applies to all bearing sections. A flow-active part is to be understood as a device which is effective for converting flow energy in cooperation with the process fluid. According to this preferred variant, the functional separation between the functional section and the bearing sections is deepened. When the bearings are modified, maintained or repaired, only the bearing sections are affected. Accordingly, the flow-active parts are concentrated in one or more functional sections.

Preferably, no bearing surfaces are arranged on the functional section. This applies not only to the first main bearing arrangement and the second main bearing arrangement, but preferably to all bearings of the turbomachine that are active during normal operation and very particularly preferably to all bearings of the turbomachine, including any backup and auxiliary bearings.

The rotor preferably has a torsionally rigid connection, in particular by means of a Hirth toothing or a micro-clamping. The torsionally rigid connection is preferably formed between the functional section and at least one bearing section and/or between the bearing sections. The torsionally rigid connection makes it possible to transfer torque from one section to the other section. In addition, an unintentional loosening of the connection between two sections can also be prevented. For example, the functional section and at least one adjacent bearing section can be clamped together in the axial direction by at least one clamping bolt. This clamping bolt is in particular formed coaxially to the axis of rotation. The torsionally rigid connection of the two adjacent sections can prevent the clamping bolt from becoming unintentional.

Hirth gearing is a rotationally periodic form-fitting profile with which the connecting partners - two adjacent sections - lie flat against each other. The contact surfaces are not aligned perpendicular to the axis of rotation, at least in sections. As a result, a relative twist would be converted into an at least partial axial displacement. If this axial offset is prevented - for example by clamping devices or clamping bolts - the relative twist is also prevented at the same time.

The invention also relates to a method for operating a turbomachine as described above. According to the invention, the rotor (in particular in normal operation) is supported in the axial direction and/or perpendicular to the axial direction (in the radial direction) exclusively by the first main bearing arrangement, the second main bearing arrangement and optionally further main bearing arrangements which do not act directly on the functional section. At the same time, the process medium is guided exclusively through flow-active parts, in particular the turbo impeller, which are not arranged on the bearing sections but only on one or more functional sections. The functional separation of the rotor into several detachably connected sections facilitates both the manufacture and the repair or overhaul and upgrading of the turbomachine.

The invention also relates to a method for overhauling a previously described turbomachine. This is particularly preferably a used turbomachine that has already been used. The method can also be applied to turbomachines that have already been completed but have not yet been used - for example because the design and/or regulatory requirements have subsequently changed.

According to the invention, the first bearing section is detached from the rotor and replaced by at least one alternative bearing section. This makes it possible to replace an existing bearing with little effort and manufacturing costs. Within the scope of the invention, it is particularly not necessary to manufacture the rotor from scratch. This has significant economic advantages, particularly due to the high costs of manufacturing a turbo impeller. The corresponding modification of the turbo machine is also significantly accelerated.

Preferably, within the scope of the method according to the invention, the housing is first opened and the rotor is at least partially removed from the housing. Furthermore, the detachable connection between the first bearing section and the functional section and, if applicable, between the first bearing section and the second bearing section is released. An alternative bearing section is then detachably connected to the functional section and, if applicable, to the second bearing section. The alternative bearing section preferably has geometrically identical connection ends with which it rests against the adjacent sections. The overhauled rotor is then reinserted into the housing and the housing is subsequently closed.

The overhaul of the turbomachine provided for in the invention can have several motives. For example, a bearing section can be replaced after damage to the bearing surface. Suspected or actual wear due to a long period of operation can also be a reason for replacing the bearing section. In this case, the first bearing section is replaced in particular by an identical alternative bearing section in order to restore the original properties.

It is also possible to improve the properties of the first main bearing arrangement while retaining the first bearing device. For example, the alternative bearing surface on the alternative bearing section can have a different surface treatment compared to the first bearing section. With identical geometry, it is possible, for example, to achieve greater surface hardness or lower friction coefficients. Alternatively or additionally, further surface optimizations, such as structuring or profiling, can also be introduced.

According to a particularly preferred embodiment of the invention, it is provided that the first main bearing arrangement is of a first bearing type and that the alternative bearing section has an alternative bearing surface for an alternative main bearing arrangement which is of a different bearing type. As a result, within the scope of the method according to the invention it is possible to change the bearing type of the first main bearing arrangement with relatively little effort. In particular, the first bearing device is simultaneously replaced by an adapted alternative bearing device.

The first bearing arrangement is particularly preferably of the fluid bearing type, in particular an oil-lubricated plain bearing, and is replaced by the other type, in particular a magnetic bearing or gas bearing type. The reason for this is that oil-lubricated plain bearings are currently the most widely used. They are very efficient and comparatively inexpensive.

The invention makes it possible to switch to a different type of bearing in the future - if this is useful. This could be the case, for example, if suitable lubricants - especially petroleum-based ones - are difficult to obtain or are disproportionately expensive, or if they cannot be used due to regulatory restrictions. The same applies if higher purity requirements are subsequently imposed on the process fluid and the entry of foreign substances such as lubricants must be reliably prevented. In this case, a contactless magnetic bearing or a process gas-flushed gas bearing (foil bearing) is advantageous. The invention therefore makes it possible not to have to commit to a particular type at this point in time, but to be able to adapt the turbomachine to the circumstances as required, without having to remanufacture the entire rotor.

The invention is explained below with reference to a figure showing an exemplary embodiment. This shows schematically the structure of a turbomachine according to the invention.

The turbomachine 1 comprises a housing 2, indicated only by dashed lines, with a rotor 3, which is mounted on the housing 2 so as to be rotatable about an axis of rotation 4 running in an axial direction (x). A first main bearing arrangement 5 and a second main bearing arrangement 6 are provided for mounting.

The first main bearing arrangement 5 has a first bearing surface 5a formed on the rotor 3 and a first bearing device 5b arranged on the housing 2 and interacting with the first bearing surface 5a. The first main bearing arrangement 5 is in the exemplary embodiment as a pure radial bearing with a cylindrically symmetrical bearing surface around the rotor 3. tion axis 4 is formed first bearing surface 5a.

In the exemplary embodiment, the second main bearing arrangement 6 is designed as a combined axial-radial bearing. It has a second bearing surface 6a and a third bearing surface 6b and a fourth bearing surface 6c, which interact with a second bearing device 6d. The fourth bearing surface 6c is also designed as a radial bearing surface cylindrically symmetrical about the rotation axis 4. The second bearing surface 6a and the third bearing surface 6b are each formed as outer surfaces of a bearing disk 7 aligned perpendicular to the rotation axis 4.

The first main bearing arrangement 5 and the second main bearing arrangement 6 are only indicated schematically and are intended to be of the type of oil-lubricated fluid bearing in the embodiment shown. This particularly also represents the state before an overhaul according to the invention.

The rotor 3 further comprises a first functional section 8, which consists of a hollow shaft 8a and a turbo impeller 8b shrunk onto it.

Furthermore, a second functional section 9 is provided, which comprises a second hollow shaft section 9a and a rotor 9b formed thereon, which is intended for interaction with the stator 10 of an electrical machine. The electrical machine can act as an electric motor and/or generator in order to convert rotational energy of the rotor 3 into electrical energy - and vice versa.

According to the invention, the rotor 3 has a first bearing section 11 and a second bearing section 12 in addition to the first functional section 8. The first bearing section 11 is indirectly connected via the second functional section 9 and the second bearing section 12 is detachably connected directly to the first functional section 8. For this purpose, Hirth gears 13 are formed at the transitions between the bearing sections 11, 12 and the functional sections 8, 9. Furthermore, the sections 8, 9, 11, 12 of the rotor 3 are clamped together by a clamping bolt 14 in the direction of the axis of rotation 4. The clamping bolt 14 has a bolt head 14a, which rests on the end of the second bearing section 12 and is secured at the axially opposite end by a clamping nut 14b.

By loosening the clamping bolt 14, it is possible to separate the sections 8, 9, 11, 12 of the rotor 3 from each other. These can then be serviced and/or replaced separately.

Claims (10)

Turbomachine (1) with a housing (2) and a rotor (3) mounted on the housing (2) with a first main bearing arrangement (5) and a second main bearing arrangement (6) so as to be rotatable about an axis of rotation (4) running in an axial direction (x), wherein the first main bearing arrangement (5) has a first bearing surface (5a) formed on the rotor (3) and a first bearing device (5b) arranged on the housing (2) and interacting with the first bearing surface (5a), wherein the second main bearing arrangement (6) has a second bearing surface (6a) formed on the rotor (3) and a second bearing device (6d) arranged on the housing (2) and interacting with the second bearing surface (6a), and wherein the rotor (3) comprises at least one turbo impeller (8b), characterized in that the rotor (3) has at least one functional section (8) comprising the turbo impeller (8b), a first bearing section (11) detachably connected to the functional section (8), and a first bearing section (11) detachably connected to the functional section (8). the functional section (8) and/or the first bearing section (11) has a second bearing section (12) connected thereto and that the first bearing surface (5a) is arranged on the first bearing section (11) and that the second bearing surface (6a) is arranged on the second bearing section (12). Turbomachine (1) after Claim 1 , characterized in that the first main bearing arrangement (5) is of a type selected from the group fluid-lubricated bearing, in particular oil-lubricated bearing, magnetic bearing or gas bearing, in particular foil bearing. Turbomachine (1) after Claim 1 or 2 , characterized in that the second main bearing arrangement (6) is of a type selected from the group fluid-lubricated bearing, in particular oil-lubricated bearing, magnetic bearing or gas bearing, in particular foil bearing. Turbomachine (1) after Claim 2 and 3 , characterized in that the first main bearing arrangement (5) and the second main bearing arrangement (6) are of the same type. Turbomachine (1) according to one of the Claims 1 until 4 , characterized in that the functional section (8) is arranged in the axial direction (x) between the first bearing section (11) and the second bearing section (12). Turbomachine (1) according to one of the Claims 1 until 5 , characterized in that the the first bearing section (11) and the second bearing section (12) do not have an impeller, in particular no flow-active parts directly attached thereto. Turbomachine (1) according to one of the Claims 1 until 6 , characterized in that the rotor (3) has a torsionally rigid connection, in particular by a Hirth toothing or a micro-clamping. Method for operating a turbomachine (1) according to one of the Claims 1 until 7 , characterized in that the rotor (3) is supported exclusively by the first main bearing arrangement (5), the second main bearing arrangement (6) and possibly further main bearing arrangements which do not act directly on the functional section (8), in the axial direction (x) and/or perpendicular to the axial direction, ie in the radial direction. Method for overhauling a turbomachine (1) according to one of the Claims 1 until 8th , characterized in that the first bearing section (11) is detached from the rotor (3) and replaced by at least one alternative bearing section. Procedure according to Claim 9 , characterized in that the first main bearing arrangement (5) is of a first bearing type, in particular of the fluid bearing type, and that the alternative bearing section has an alternative bearing surface for an alternative main bearing arrangement which is of a different bearing type, in particular of the magnetic bearing or gas bearing type.

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