EP2386767B1 - Helico-axial pump and method for bearing a rotor in a helico-axial pump - Google Patents

Description

The invention relates to a helico-axial pump for pumping multiphase mixtures and a method for mounting a rotor in a helico-axial pump.

When pumping multiphase mixtures, such as crude oil, which contains natural gas as well as oil and often also water and solids such as sand, the problem arises that the efficiency of the pump devices used decreases with increasing gas content in the multiphase mixture. For example, in the case of low gas densities, the use of pump devices with radial impellers is no longer possible or no longer economical from a volumetric gas / liquid ratio of greater than 0.04 to 0.06. In conventional conveying systems, when the gas content is higher, the gaseous phase of the multiphase mixture is first separated from the liquid and the two phases are then conveyed separately under different conveying conditions. Such a separation of the liquid and gaseous phase of the multiphase mixtures is dependent on the special conditions of use at the location of the promotion and not always possible or economical. Special pumping or compression devices have therefore been developed to reduce the volumetric gas / liquid ratio of the multiphase mixtures to be conveyed to such an extent that a conventional pumping device can then be used for further conveying, for example a displacement pump, a rotary pump or a jet pump.

Such pumping or compression devices for multiphase mixtures with an increased gas content are, for example, already from the US 2001/005483 A1 , the GB-A-1 561 454 , the EP 0 486 877 or the U.S. 5,961,282 known.

For example, the hybrid pump is according to U.S. 5,961,282 a system for compressing a multiphase mixture which, in addition to a liquid phase, can in particular comprise a considerable proportion of gas. The pump includes a multi-stage axial flow pump to reduce the relative gas proportion, i.e. the axial flow pump is used to increase the density of the multiphase mixture so that it can finally be pumped from a lower level to a higher level by another conventional centrifugal pump, for example from the bottom of the Marine to an oil rig, ship, or land-based facility.

document US 2002/0187037 A1 shows a hybrid pump system for conveying a multi-phase mixture consisting of a production pump which can be supplemented with several modularly connectable compression pumps. The compression pump includes a multi-stage axial flow pump to reduce the relative gas proportion so that it can then be pumped to a higher level with greater efficiency by a conventional centrifugal pump.

As already mentioned, the helico-axial pump acting as a compressor comprises a rotor with several compression stages, in practice for example with up to sixteen or more stages, so that the multiphase mixture gradually changes from a relatively low density to a high relative Volume fraction of gas can be compressed up to a highly compressed multiphase mixture with such a high density that the highly compressed mixture can be conveyed further with a conventional feed pump.

A known compression stage K 'of a rotor 2' of a helico-axial pump 1 'is shown schematically in FIG Figures 1a and 1b shown, where for clarity in Figure 1b a section II of a section according to Fig. 1a is shown parallel to the longitudinal axis A '.

Each compression stage K 'comprises a rotating impeller 3' with screw 31 ', the rotating impeller 3' resembling a short Archimedean screw, and an adjoining stator 4 'consisting of a plurality of static, i.e. non-rotating blades 41' . Impeller 3 'and stator 4' are mounted in relation to a common pump shaft 5 'in such a way that the impeller 3' is set in rotation by the pump shaft 5 'in the operating state, while the stator 4' is caused by the rotary movement of the pump shaft 5 ' is decoupled and therefore does not rotate with respect to the impeller 3 '. The pump shaft 5 'extends along a longitudinal axis A'. The majority of the compression stages K 'are arranged in series one behind the other in an essentially tubular pump housing 6'.

The rotating screw 31 'conveys the multiphase mixture M' in the direction of the arrow, for example from an in Figures 1a and 1b previous compression stage K ', not shown, in the stator 4', whereby kinetic energy is converted into pressure energy in the stator 4 ', which leads to the compression of the multiphase mixture M'.

In order to obtain a sufficiently high compression of the multiphase mixture M ', in practice, as already mentioned, a larger number of for example up to sixteen or even more compression stages K', each consisting of an impeller 3 'and a stator 4' in Series are provided, which inevitably leads to a considerable length of the helico-axial pump 1 '.

The decisive disadvantage of such long rotors 2 'formed from a multiplicity of compression stages K' is therefore that they are very difficult to control in terms of vibration. In the interior of the tubular pump housing 6 ', these long rotors 2' form an oscillatable system which can in particular form various transverse oscillation modes which can be so intense that the Pump can no longer be operated at a specified number of revolutions or in a certain field of rotation. In addition, the efficiency of the pumps 1 'can also be reduced and in the worst case even damage to the pump 1' is to be feared if the rotor 2 'begins to vibrate so strongly and uncontrollably that parts of the rotor 2' such as the impellers 3 'come into contact, for example, with the pump housing as a result of the oscillating movement. The type and intensity of the vibrations of the rotor 2 'depends not only on the special geometry but also on the operating state of the pump 1', the multiphase mixture M 'to be pumped, the speed of the pump 1' and other known and sometimes not exactly known parameters so that it is hardly possible to get the problems with the damaging vibrations of the rotor 2 'under control simply by adapting the geometrical relationships of known pumps 1' or by using new materials.

There is a clear desire for pumps with an ever increasing number of compression stages so that multiphase mixtures with an ever higher proportion of gas can be compressed better and better, i.e. to ever higher pressures, so that the multiphase mixture compressed in this way is more reliable and over ever greater pressure or pressure levels. Height differences can be pumped further.

The object of the invention is therefore to propose a helico-axial pump for pumping multiphase mixtures, in which the damaging vibrations of the rotor are largely avoided and the vibrations of the rotor are reduced or damped to a predeterminable level, so that on the one hand an improved running of the Rotor can be achieved in the operating state and the pump can be operated on the other hand at speeds or in a field of rotation in which the from the state Helico-axial pumps known from the art cannot be operated due to the damaging vibrations of the rotor described above. In addition, the new pump should alternatively or simultaneously be equipped with more compression stages than is possible with the pumps previously known in the prior art, in which the length of the pump and thus the maximum number of compression stages are limited by the vibrations of the rotor in the operating state is.

The subjects of the invention that achieve this object are characterized by the features of the independent claims of the respective category.

The dependent claims relate to particularly advantageous embodiments of the invention.

The invention thus relates to a helico-axial pump for pumping a multiphase mixture according to claim 1, which helico-axial pump comprises a rotor rotatably mounted in a pump housing about a longitudinal axis, with a first partial rotor and a second partial rotor, the first partial rotor and the second partial rotor comprises a compression stage with a helico-axial impeller and a stator for compressing the multiphase mixture. According to the invention, a hydrodynamic stabilization bushing with a stabilization surface is provided and configured between the first partial rotor and the second partial rotor in such a way that a stabilization gap is formed in front of the stabilization surface, so that in the operating state a hydrodynamic stabilization layer can be formed from a stabilization medium in the stabilization gap.

It is therefore essential for the invention that a hydrodynamic stabilization bushing with a stabilization surface is provided in the pump housing, so that a stabilization gap is formed in front of the stabilization surface, in which stabilization gap a hydrodynamic stabilization layer is formed when the pump is in operation.

The rotor dynamics are therefore decisively improved by the present invention, because the damping and rigidity of the oscillatable rotor system are decisively increased by the stabilization layer.

The damaging vibrations of the rotor are largely avoided by the formation of the stabilization layer in the stabilization gap in front of the stabilization surface of the stabilization bushing and are reduced or damped at least to a predeterminable tolerable amount, so that the pump can also be operated at one speed or in a specific field of rotation where this has hitherto no longer been possible without using the stabilizing layer according to the invention. In addition, a higher efficiency of the pump and a smoother, improved run of the rotor in the operating state can possibly even be achieved. Of course, this ultimately means that not only can energy be saved for operating the pump, but also the maintenance intervals can be extended, which means that the associated costs can be drastically reduced and, at the same time, the service life of the pump is significantly increased.

Another particular advantage is that the invention makes it possible for the first time to design pumps with a much higher number of compression stages than was previously possible. Up to now, the possible number of compression stages was limited by the massively increasing vibrations of the rotor with the increasing number of compression stages. With the invention, the rotor can be safely stabilized practically at any length.

In the case of a helico-axial pump according to the invention, the stabilization layer in the stabilization gap along the essentially axially extending stabilization surface of the hydrodynamic stabilization bushing forms quasi automatically, so that in a simple embodiment, which, however, is of particular importance in practice, apart from a suitable setting of the Size or the shape of the stabilization gap or the stabilization bushing and / or its stabilization surface, no further structural measures need to be undertaken.

If the geometry of the stabilization gap in a helico-axial pump according to the invention is set according to the requirements, a pressure difference between the multiphase mixture located in the first partial rotor and the one located in the second partial rotor forms in the operating state across the stabilization gap such that a specifiable flow of multiphase mixture from the second partial rotor via the stabilization gap back to the first partial rotor is automatically established, whereby a stabilization layer for stabilizing or damping the damaging vibrations of the rotor is automatically formed.

The degree, that is to say the strength of the damping, can be adapted in a simple manner depending on the technical requirements or specifications in a helico-axial pump according to the invention. This can be done, for example, by a suitable choice of the geometry, for example the geometric shape or width of the stabilization gap.

A helico-axial pump according to the invention is designed in the form of a so-called back-to-back arrangement. The person skilled in the art understands a back-to-back arrangement to be an arrangement of two pump rotors in series, which thus forms a pump with two pressure stages. The medium to be pumped is fed to the first pressure stage via a suction opening of the pump, the medium passing through the first pressure stage in a first axial direction, the pressure of the medium to be pumped being increased to a first intermediate pressure. From the first pressure stage, the medium is then fed to the second pressure stage via a channel system in such a way that the medium passes through the second pressure stage in a second axial direction, which is opposite to the first axial direction of the first pressure stage. In the second pressure stage that becomes The medium is then brought to the desired final pressure and discharged from the pump via a pressure opening for further use.

It is essential for the back-to-back arrangement of the pumps known from the prior art that the direction of flow of the medium in the first pressure stage is opposite to the direction of flow in the second pressure stage. In the known pumps, the back-to-back arrangement serves exclusively to at least partially compensate for the enormous thrust forces which act in the axial direction on the bearings of the pump shaft and thus to relieve the bearings. The enormous axial thrust forces are due to the fact that in these pumps known from the prior art, very high pressures with very large components are generated in the axial direction.

Vibrations of the pump rotor play a very subordinate role here because the rotors themselves usually do not have a large axial extension and / or only consist of one compression stage and / or an additional mechanical bearing, for example a mechanical bearing, between the first pressure stage and the second pressure stage Ball bearing is provided that additionally mechanically supports the pump rotor in the middle.

Since the axial pressure components of helico-axial pumps are rather small compared to other conventional pumps, the thrust forces that act in the axial direction on the bearings of the helico-axial pump do not play a decisive role. For this reason, a back-to-back arrangement for helico-axial pumps has so far hardly been considered, because the known advantage of the back-to-back arrangement cannot actually be used with helico-axial pumps.

The essential finding of the invention is therefore that the back-to-back arrangement can be used successfully in the case of helico-axial pumps if a stabilizing bushing according to the invention is provided between the first partial rotor and the second partial rotor so that Due to the pressure gradient between the first partial rotor and the second partial rotor in the stabilization gap, a stabilization layer can form from the stabilization medium, which is particularly preferably the multiphase mixture to be pumped itself, so that the vibrations of the rotor are dampened to a predetermined, harmless level by the stabilization layer.

According to the invention, the first partial rotor and the second partial rotor are thus provided in a back-to-back arrangement in the pump housing such that the multiphase mixture can be fed to a first input compression stage of the first partial rotor via a suction opening, a first annular space and a second annular space, and via a first output compression stage can be removed again from the first partial rotor into a first cross channel. From the first cross channel, the multiphase mixture can then be fed via a third annular space to a second input compression stage of the second partial rotor and can be discharged again from the second partial rotor via a second output compression stage via a second cross channel, a fourth annular space and a pressure opening from the helico-axial pump. The first output compression stage and the second output compression stage are each arranged adjacent to the stabilization bushing.

As will be explained in more detail later in the drawings, the stabilizing bushing is designed and arranged on the rotor in such a way that the stabilizing gap is formed between the stabilizing bushing and the pump housing. Simultaneously or alternatively, however, the stabilizing bushing can be designed and arranged on the rotor in such a way that the stabilizing gap is formed between the stabilizing bushing and the rotor.

In an exemplary embodiment that is also important in practice, a hydrodynamic stabilizing element with a stabilizing surface is also provided and configured in such a way that the Stabilization gap is formed so that in the operating state a hydrodynamic stabilization layer can be formed from the stabilization medium in the stabilization gap, the additional stabilization element preferably being a cover ring which surrounds the helico-axial impeller in the circumferential direction so that the stabilization gap is formed between the cover ring and the pump housing . Such a cover ring can be provided on all helico-axial impellers of a rotor, or only on selected individual impellers, which of course makes the manufacture of the rotor significantly less complex and cheaper.

In another important embodiment of the present invention, the additional stabilizing element is provided in the form of a stabilizing sleeve between two adjacent compression stages on the rotor. A stabilization sleeve can be provided between all adjacent compression stages of a rotor, whereby particularly good damping of the vibrations of the rotor can be achieved, especially with very high loads, or only between individual selected pairs of compression stages, which of course means that the manufacture of the rotor is significantly less becomes complex and cost-effective.

The stabilization sleeve can be designed and arranged on the rotor in such a way that the stabilization gap is formed between the stabilization sleeve and the pump housing, and / or the stabilization sleeve can also be designed and arranged on the rotor in such a way that the stabilization gap is formed between the stabilization sleeve and the rotor . In particular, both variants can be implemented on one and the same rotor, as a result of which particularly smooth running and particularly good damping of the rotor vibrations can be achieved in certain cases.

If the geometry of the stabilization gap of the additional hydrodynamic stabilization element in a helico-axial pump according to the invention is set according to the requirements, a pressure difference between the multiphase mixture, which is at a higher pressure level and that which is at a lower pressure level, forms in the operating state above the stabilization gap is located in such a way that a predeterminable flow of multiphase mixture is automatically set via the stabilization gap from the higher pressure level back to the lower pressure level, which automatically creates a stabilization layer for additional stabilization or damping of the damaging vibrations of the rotor.

To form the hydrodynamic stabilization layer, however, additional measures can also be taken, especially if the vibrations that occur are very strong or if the damping is dependent on certain operating parameters, such as the load under which the pump is operated, or depending on the Speed should be set.

Thus, it is particularly preferred to use an already more highly compressed multiphase mixture, which is taken from a compression stage in which the multiphase mixture is already more compressed than it is compressed in the stage in which it is used to form the stabilization layer. As an alternative or at the same time, however, a multiphase mixture compressed in the same compression stage can be used to form the hydrodynamic stabilization layer, as can be seen, for example, on the basis of FIG Fig. 4 will be explained in detail. For this purpose, special channels or lines can be provided in or on the pump housing, for example, which connect a feed opening for feeding the multiphase mixture into the stabilization gap with the pressure outlet of a prescribable compression stage.

It goes without saying that the stabilization medium for the formation of the stabilization layer can in special cases also be made available from other external sources, for example from a pressure accumulator or from a pump, which the medium for the formation of the stabilization layer under a predeterminable, in particular under provides a controllable and / or adjustable pressure for introduction into the stabilization gap. Also, the stabilization medium for forming the stabilization layer does not necessarily have to be the multiphase mixture to be pumped, but can also be a different stabilization medium, e.g. an oil, water or another liquid or gaseous stabilization medium or fluid.

It is also possible, for example, for the pressure of the multiphase mixture introduced into the stabilization gap to be controlled and / or regulated by means of a valve known per se. It is also possible, for example, to feed the multiphase mixture simultaneously or alternatively from different compression stages to the stabilization gap, whereby the pressure in the stabilization gap and thus the degree of damping or the stiffness of the oscillating rotor can be adjusted very easily and very flexibly to different requirements and can be adapted to changing operating conditions.

As will be explained later using the drawings using particularly preferred exemplary embodiments, the stabilization gap can be formed on the additional stabilization element and of course also on the stabilization bushing, for example between the stabilization surface and the pump housing and / or can also be provided between the stabilization surface and the rotor .

In a particularly preferred embodiment of the present invention, a feed channel can be provided which is designed and arranged in such a way that, in order to form the hydrodynamic stabilization layer in the stabilization gap, a multiphase mixture under a predeterminable pressure and, as a result, a predeterminable amount of multiphase mixture through the feed channel to the stabilization gap can be fed in, the feed channel preferably being provided in a split ring.

For example, the stabilization element can be designed as a stator with a feed channel, the feed channel being designed and arranged on the stator in such a way that, for the formation of the hydrodynamic stabilization layer in the stabilization gap, a predeterminable amount of a stabilization medium, in particular a multiphase mixture, through the feed channel under a predeterminable pressure Stabilization gap can be fed.

In a further embodiment, the feed channel can be arranged and designed on the pump housing in such a way that a predeterminable amount of stabilization medium, in particular a multiphase mixture, can be fed through the feed channel to the stabilization gap in order to form the hydrodynamic stabilization layer in the stabilization gap.

Or a feed channel is arranged and designed on the rotor in such a way that a predeterminable amount of stabilization medium, in particular a multiphase mixture, can be fed through the feed channel to the stabilization gap in order to form the hydrodynamic stabilization layer in the stabilization gap.

As already mentioned, in a helico-axial pump according to the invention, the stabilizing medium, in particular the multiphase mixture, can particularly preferably be supplied to the supply channel from a compression stage are supplied at which a higher pressure level prevails than at that compression stage to which it is supplied as a stabilizing medium. Alternatively or simultaneously, however, a multiphase mixture compressed in the same compression stage can also be used to form the hydrodynamic stabilization layer.

Finally, the invention also relates to a method for the hydrodynamic mounting of a rotor of a helico-axial pump according to the present invention. According to the invention, a hydrodynamic stabilization bushing with a stabilization surface is provided and designed in the pump housing in such a way that a stabilization gap is formed along the essentially axially extending stabilization surface, so that in the operating state a hydrodynamic stabilization layer is formed from a stabilization medium in the stabilization gap for hydrodynamic bearing of the rotor.

Fig. 1a

eine Kompressionsstufe einer aus dem Stand der Technik bekannten helico-axialen Pumpe;

Fig. 1b

eine Pumpe gemäss Fig. 1a teilweise im Schnitt;

Fig. 2

ein Ausführungsbeispiel einer erfindungsgemässen helico-axialen Pumpe in Back-to-Back Anordnung;

Fig. 3

eine Detaildarstellung der Back-to-Back Anordnung gemäss Fig. 2 im Betriebszustand;

Fig. 4

ein Ausführungsbeispiel mit einem zusätzlichen hydrodynamischen Stabilisierungselement in Form eines Deckrings;

Fig. 5a

ein Ausführungsbeispiel der Fig. 4 mit zusätzlicher Einspritzung am Deckring;

Fig. 5b

das Ausführungsbeispiel der Fig. 5a mit Einspritzung unter höherem Druck;

Fig. 6a

ein drittes Ausführungsbeispiel gemäss Fig. 4 mit Einspritzung am Stator;

Fig. 6b

ein anderes Ausführungsbeispiel gemäss Fig. 6a ohne Deckring am helico-axialen Laufrad;

Fig. 6c

ein weiteres Ausführungsbeispiel gemäss Fig. 6b mit Einspritzung aus dem Rotor;

Fig. 7a

ein viertes Ausführungsbeispiel gemäss Fig. 4 mit Stabilisierungshülse und Einspritzung;

Fig. 7b

ein anderes Ausführungsbeispiel gemäss Fig. 7a ohne Deckring am helico-axialen Laufrad.

The invention is explained in more detail below with reference to the drawing. It shows in a schematic representation:

Fig. 1a

a compression stage of a helico-axial pump known from the prior art;

Figure 1b

a pump according to Fig. 1a partly in section;

Fig. 2

an embodiment of a helico-axial pump according to the invention in a back-to-back arrangement;

Fig. 3

a detailed representation of the back-to-back arrangement according to Fig. 2 in operating condition;

Fig. 4

an embodiment with an additional hydrodynamic stabilization element in the form of a cover ring;

Figure 5a

an embodiment of the Fig. 4 with additional injection on the cover ring;

Figure 5b

the embodiment of Figure 5a with injection under higher pressure;

Figure 6a

a third embodiment according to Fig. 4 with injection on the stator;

Figure 6b

another embodiment according to Figure 6a without cover ring on the helico-axial impeller;

Figure 6c

another embodiment according to Figure 6b with injection from the rotor;

Figure 7a

a fourth embodiment according to Fig. 4 with stabilizing sleeve and injection;

Figure 7b

another embodiment according to Figure 7a without cover ring on the helico-axial impeller.

Based on the Figures 1a and 1b The prior art described has already been described in detail at the beginning, so that a further discussion of the Figures 1a and 1b superfluous.

At this point, it should also be pointed out that, in order to better differentiate the invention from the prior art, those reference symbols in the drawings which relate to features or embodiments from the prior art are provided with an apostrophe, while reference symbols to features according to the invention Embodiments do not have an apostrophe.

Based on Fig. 2 a first embodiment of a helico-axial pump according to the invention in a back-to-back arrangement is to be explained schematically.

The helico-axial pump 1 for pumping a multiphase mixture M according to Fig. 2 comprises a rotor 2 rotatably mounted in a pump housing 6 about a longitudinal axis A, with a first partial rotor 21 and a second partial rotor 22. The rotor 2 is driven by a drive 1000, which is an electric motor 1000, for example. The first partial rotor 21 and the second partial rotor 22 for compressing the multiphase mixture M each comprise several compression stages K with a helico-axial impeller 3 and a stator 4. According to the present invention, a hydrodynamic stabilizing bushing 70 with a stabilizing surface 700 is located between the first partial rotor 21 and the second partial rotor 22 are provided that a stabilization gap 8 is formed in front of the stabilization surface 700, so that a hydrodynamic stabilization layer S can be formed from a stabilization medium in the stabilization gap 8 when the pump 1 is in the operating state.

The Fig. 3 shows a detailed representation of the back-to-back arrangement according to FIG Fig. 2 in the operating state of the helico-axial pump 1. As can be clearly seen, the first partial rotor 21 and the second partial rotor 22 are arranged in a back-to-back arrangement on a common pump shaft 5 in the pump housing 6. The first partial rotor 21 and the second partial rotor 22 are separated from one another by the stabilizing bushing 70. The multiphase mixture M is fed via a suction opening 101, a first annular space R1 and a second annular space R2 to a first input compression stage K1E of the first partial rotor 21 and discharged again via a first output compression stage K1A from the first partial rotor 21 into a first cross channel KR1 from the first partial rotor 21. Coming from the first cross channel KR1, the multiphase mixture M is then fed via a third annular space R3 to a second input compression stage K2E of the second partial rotor 22 and via a second output compression stage K2A from the second partial rotor 22 via a second cross channel KR2, a fourth annular space R4 and a pressure opening 102 is discharged from the helico-axial pump for further use. In order to obtain a maximum pressure difference ΔP across the stabilization bushing 70 and thus ensure the formation of an optimal stabilization layer S in the stabilization gap 8, the first output compression stage K1A and the second output compression stage K2A are each arranged adjacent to the stabilization bushing 70.

In the example of Fig. 3 the stabilizing bushing 70 is designed and arranged on the rotor 2 in such a way that the stabilizing gap 8 is formed between the stabilizing bushing 70 and the pump housing 6. As later, completely analogous to the Figures 6a to 7b will be explained in more detail, the stabilizing bushing 70 can alternatively or even simultaneously be designed and arranged on the rotor 2 in such a way that the Stabilization gap 8 is formed between the stabilization bushing 70 and the rotor 2.

Based on Fig. 4 , which shows a section with two adjacent compression stages K of a rotor 2 according to the invention in a schematic representation, an embodiment with an additional hydrodynamic stabilization element in the form of a cover ring will be briefly discussed.

The rotor 2 of the helico-axial pump 1 is rotatably mounted in the pump housing 6 about a longitudinal axis A. The rotor 2 comprises the compression stages K with a helico-axial impeller 3 and a stator 4 in order to compress the multiphase mixture M in a manner known per se.

In addition to the in Fig. 4 Stabilization sleeve 70 according to the invention, not explicitly shown, has a hydrodynamic stabilization element 7, 71 with a stabilization surface 700 provided in the pump housing 6 and configured in such a way that a stabilization gap 8 is formed in front of the stabilization surface 700 so that in the operating state a hydrodynamic stabilization layer S from the multiphase mixture is also here M is formed in the stabilization gap 8. In the present example the Fig. 4 the additional stabilization element 7 is a cover ring 71 which surrounds the helico-axial impeller 3 in the circumferential direction, so that the stabilization gap 8 can be formed between the cover ring 71 and the pump housing 6.

For the sake of clarity, only one or two compression stages K are shown in each of the following figures. Even if it is possible in principle that a helico-axial pump 1 comprises only a single compression stage K, a helico-axial pump 1 according to the invention, ie the first partial rotor 21 and the second partial rotor 22, will in practice comprise a multiplicity of compression stages K , for example up to sixteen compression stages K or even significantly more compression stages K, which are preferably arranged one behind the other in series along the longitudinal axis A, so that a sufficient overall compression of the multiphase mixture M can be generated in a manner known per se, and the multiphase mixture M compressed in this way, for example can be promoted with a downstream pressure pump to a higher level and / or over long distances for further processing. In the embodiment according to Fig. 4 We formed the stabilization layer S from the stabilization medium M in the stabilization gap 8 in that the multiphase mixture M, as shown symbolically by the double arrow M, is fed from the left to the left compression stage K as shown and is compressed by this in a known manner, which of course also is accompanied by a corresponding increase in pressure, which is also established as the pressure difference ΔP across the helico-axial impeller 3 compression stage K.

Due to the pressure difference ΔP, as indicated by the small curved arrows M, from the higher pressure level on the right in the illustration, the multiphase mixture M is pressed into the stabilization gap 8, whereby the hydrodynamic stabilization layer S is automatically formed between the stabilization surface 700 of the cover ring 7 and the pump housing 6, whereby the oscillations of the rotor 2 or the partial rotors 21, 22 are damped and the running of the rotor 2 is stabilized.

It goes without saying that in a rotor 2 the cover ring 71 can either be formed on all helico-axial impellers 3 of the rotor, or only on certain selected helico-axial impellers 3. Otherwise, depending on the application or depending on the special Requirements of the cover ring 71 completely cover a helico-axial impeller 3 or a certain predeterminable area of the circumference of the helico-axial impeller 3.

Based on Figure 5a is a second embodiment according to Fig. 4 shown schematically, which differs from that of the Fig. 4 differs in that an injection of the stabilization medium M is provided on the cover ring 71 of the helico-axial impeller 3. Here, stabilization medium M is additionally introduced through the feed channel 400, 402 into the stabilization gap 8 to form the stabilization layer S. It goes without saying that here too, as in the discussion of the Fig. 4 described, a pressure difference .DELTA.P is set over the helico-axial impeller 3 in the operating state, whereby the stabilization layer S is already partially formed. By using the injection of stabilization medium M under increased pressure through the supply channel 400, 402, however, an even better stabilization layer S can be built up in the stabilization gap 8, so that even very long rotors 2 or very heavily loaded rotors 2 are still sufficiently damped and safely stored can be.

In principle, stabilization medium can also be injected into the stabilization gap S of the stabilization bushing 70.

The embodiment of Figure 5b differs from that of the Figure 5a only because the stabilization medium M is injected on the cover ring 71 of the helico-axial impeller 3 under a significantly higher pressure than in the example of FIG Figure 5a . This can be clearly seen from the fact that the stabilization medium M at Figure 5b According to the illustration, it is pressed out of the stabilization gap 8 both to the left, ie in the direction of a compression stage K with a lower pressure level, and to the right, ie also in the direction of a compression stage with a higher pressure level.

In contrast, the example is Figure 5a the pressure with which the stabilization medium M is introduced through the supply channel 400, 402 into the stabilization gap 8 to form the stabilization layer S. becomes significantly smaller than in Fig. 3a . This can be clearly seen from the fact that the stabilization medium M at Fig. 3 According to the illustration, it can enter the stabilization gap 8 from the right, ie from a compression stage with a higher pressure level.

As already described, the stabilization medium M can be made available by an external pressure accumulator or an external pump; however, it is preferably made available by another compression stage K, which has a higher pressure level.

Using the schematic Figure 6a is a third embodiment according to Fig. 4 shown with an injection of the stabilization medium on the stator 4. Here, a feed channel 400, 401 in the form of a bore is provided on the stator 4, for example on a blade of the stator 4, or a separate feed channel 400, 401 can also be provided, which is as in Figure 6a shown, extends through the pump housing 6 to the stabilization gap 8, so that between the rotor 2 and the stabilization surface 700 of the stator 4 formed as a stabilization element 73, a stabilization layer S made of stabilization medium M, which in the specific example of Figure 6a Multiphase mixture M is from a different compression stage, can be formed.

In Figure 6b is another embodiment according to Figure 6a shown, which differs from that of the Figure 6a differs only in that no cover ring 71 is provided on the helico-axial impeller 3. Such a simplified construction can, for example, always be used successfully when the stabilization of the rotor 2 by the stabilization layer S on the stator 4 is already sufficient.

Figure 6c shows a further variant of the embodiment according to Figure 6b . Here, the stabilization medium M is not supplied via a supply channel 400, 401 through the pump housing 6, but rather by injection of the stabilization medium M takes place through a supply channel 400, 403 which is formed in the rotor 2. For this purpose, the rotor 2 can, for example, have a hollow rotor shaft or suitable channels or lines can be formed in the rotor shaft through which the stabilization medium M, for example multiphase mixture M, can be fed from a compression stage K at a higher pressure level.

The Figure 7a shows a fourth, different embodiment according to FIG Fig. 4 , in which an additional stabilization sleeve 72 is provided between two adjacent compression stages K, the stabilization medium M being injected into the stabilization gap 8 through a feed channel 400, 402 guided through the pump housing 6. Such an arrangement is particularly suitable when a very high stability or damping of the rotor 2 has to be achieved. In this case, the injection into the stabilization gap 8 can in principle also be analogous to Figure 6c take place through the rotor shaft of the rotor 2. It is also as shown in Figure 7b Of course, it is also possible, as shown, that the cover ring can be dispensed with on all or on various helico-axial impellers 3.

In special cases, it is of course also possible that, as an alternative or in addition to the stabilizing sleeve 72 between two adjacent compression stages K, a stabilizing sleeve 72 can also be provided within a compression stage K between the helico-axial impeller 3 and the stator 4. The person skilled in the art immediately understands that a stabilizing sleeve 72 does not have to be provided at each or between each pair of compression stages K.

It goes without saying that all of the above-described exemplary embodiments of the invention are only to be understood as exemplary or exemplary and the invention is determined exclusively by the following claims.

Claims (10)

1. A helico-axial pump for conveying a multiphase mixture (M), which helico-axial pump includes a rotor (2) rotatably journalled about a longitudinal axis (A) in a pump housing (6) and having a first part rotor (21) and a second part rotor (22), wherein the first part rotor (21) and the second part rotor (22) includes a compression stage (K, K1E, K1A, K2E, K2A) having a helico-axial impeller (3) and a stator (4) for the compression of the multiphase mixture (M), wherein a hydrodynamic stabilization bush (70) having a stabilization surface (700) is provided and arranged between the first part rotor (21) and the second part rotor (22) such that a stabilization gap (8) is formed along the substantially axially extending stabilization surface (700) so that in the operating state a hydrodynamic stabilization layer (S) can be formed from a stabilization medium in the stabilization gap (8), wherein a first output compression stage (K1A) of the first part rotor (21) and a second output compression stage (K2A) of the second part rotor (22) are each arranged adjacent to the stabilization bush (70), wherein the first part rotor (21) and the second part rotor (22) are provided in a back-to-back arrangement in the pump housing (6), characterized in that the multiphase mixture (M) can be supplied via an intake opening (101) to a first annular space (R1) and a second annular space (R2) of a first input compression stage (K1E) of the first part rotor (21) and can be discharged again via a first output compression stage (K1A) from the first part rotor (21) into a first cross-passage (KR1), and the multiphase mixture (M) can be supplied from the first cross-passage (KR1) via a third annular space (R3) to a second input compression stage (K2E) of the second part rotor (22) and can be discharged again via a second output compression stage (K2A) from the second part rotor (22) via a second cross-passage (KR2), a fourth annular space (R4), and a pressure opening (102) from the helico-axial pump.
2. A helico-axial pump in accordance with one of the claims 1, wherein the stabilization bush (70) is provided and arranged at the rotor (2) such that the stabilization gap (8) is formed between the stabilization bush (70) and the pump housing (6); and/or wherein the stabilization bush (70) is provided and arranged at the rotor (2) such that the stabilization gap (8) is formed between the stabilization bush (70) and the rotor (2).
3. A helico-axial pump in accordance with any one of the preceding claims, wherein a hydrodynamic stabilization element (7, 71, 72, 73) having a stabilization surface (700) is provided and is arranged such that the stabilization gap (8) is formed along the substantially axially extending stabilization surface (700) so that in the operating state a hydrodynamic stabilization layer (S) can be formed from the stabilization medium in the stabilization gap (8).
4. A helico-axial pump in accordance with claim 3, wherein the hydrodynamic stabilization element (7, 71, 72, 73) is a cover ring (71) which surrounds the helico-axial impeller (3) in the peripheral direction so that the stabilization gap (8) is formed between the cover ring (71) and the pump housing (6); and/or wherein the hydrodynamic stabilization element (7, 71, 72, 73) is a stabilization sleeve (72) so that the stabilization gap (8) is formed between the stabilization sleeve (72) and the pump housing (6).
5. A helico-axial pump in accordance with any one of the preceding claims, wherein a supply passage (400, 401, 402, 403) is provided which is provided and arranged so that a pre-definable quantity of stabilization medium (M), in particular multiphase mixture (M), is supplyable through the supply passage (400, 401, 402, 403) to the stabilization gap (8) for the formation of the hydrodynamic stabilization layer (S) in the stabilization gap (8), wherein the supply passage (400, 401, 402, 403) is preferably provided in a gap ring (9).
6. A helico-axial pump in accordance with any one of the claims 3 to 5, wherein the stabilization element (7, 71, 72, 73) is the stator (4) having a supply passage (401) which is provided and arranged at the stator (4) such that a pre-definable quantity of stabilization medium (M) can be supplied through the supply passage (401) to the stabilization gap (8) for the formation of the hydrodynamic stabilization layer (S) in the stabilization gap (8).
7. A helico-axial pump in accordance with any one of the preceding claims, wherein a supply passage (402) is provided and arranged at the pump housing such that a pre-definable quantity of stabilization medium (M) can be supplied through the supply passage (402) to the stabilization gap (8) for the formation of the hydrodynamic stabilization layer (S) in the stabilization gap (8).
8. A helico-axial pump in accordance with any one of the preceding claims, wherein a supply passage (403) is provided and arranged at the rotor (2) such that a pre-definable quantity of stabilization medium (M) can be supplied through the supply passage (403) to the stabilization gap (8) for the formation of the hydrodynamic stabilization layer (S) in the stabilization gap (8).
9. A helico-axial pump in accordance with any one of the claims 5 to 8, wherein the stabilization medium (M) is supplied to the supply passage (400, 401, 402, 403) from a compression stage (K) at which a higher-pressure level is present.
10. A method for the hydrodynamic journalling of a rotor (2) a helico-axial pump (1) in accordance with any one of the claims 1 to 9, characterized in that the hydrodynamic stabilization bush (70) having the stabilization surface (700) is provided and arranged in the pump housing (6) such that a stabilization gap (8) is formed along the substantially axially extending stabilization surface (700) so that the hydrodynamic stabilization layer (S) is formed from the stabilization medium in the stabilization gap (8) for the hydrodynamic journalling of the rotor (2).

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