Multiphase pump of the screw spindle pump type

Abstract

A multiphase pump of the screw spindle pump type, including a spindle housing with a spindle packet, received therein, including a drive spindle and at least one idler spindle meshing therewith, via which spindle packet a fluid to be delivered is able to be delivered from a suction side, at which the fluid is under a suction pressure, to a pressure side, at which the fluid is under an increased outlet pressure. The drive spindle and the idler spindle are each mounted rotatably in the spindle housing via bearings. The bearings are hydrodynamic plain bearings in which the drive spindle and the idler spindle are received via a bearing gap. A feed device for feeding a fluid lubricating medium at a higher pressure than the suction pressure is provided in each bearing gap.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] The present application claims priority of DE 10 2025 111 974.0, filed Mar. 27, 2025, the priority of this application is hereby claimed, and this application is incorporated herein by reference.BACKGROUND OF THE INVENTION

[0002] Such a multiphase pump is used for delivering a mixture of different media. This may be, for example, a mixture of a liquid and a gas, i.e., for example, a water / gas mixture or an oil / gas mixture, or a mixture consisting of two different liquids, i.e., for example, a water / oil mixture or a water / sand / oil mixture. Usually, such a multiphase pump is embodied in the form of a screw spindle pump. Such a screw spindle pump comprises a spindle housing which is usually received in an external housing and in which a spindle packet is arranged. This spindle packet comprises a drive spindle, which is connected to an externally arranged drive motor. Also provided is at least one idler spindle, wherein both the drive spindle and the idler spindle have a corresponding spindle profile and the spindle profiles mesh with one another such that the drive spindle conjointly drives the idler spindle, via which the fluid, i.e. in this case the mixture, is delivered. Frequently, provision is also made of two idler spindles that are arranged next to the drive spindle in a manner offset through 180° and both mesh with the latter. Via this spindle packet, the fluid to be delivered is delivered from a suction side, at which the fluid is present with a starting pressure, to a pressure side, at which it is present with a starting pressure and where it is then withdrawn.

[0003] The spindle, regardless of whether it is the drive spindle or the or each idler spindle, is mounted rotatably in the spindle housing in each case via corresponding bearing means. These bearing means are usually rolling bearings, which are received in corresponding bearing seats on the spindle housing and are arranged on a corresponding bearing seat of the respective spindle. The rolling bearings are sealed off via corresponding sealing rings from the actual interior of the spindle housing, in which the fluid to be delivered is present. Depending on the design, it is also possible for a transmission to be provided, via which the spindles are coupled, for example in the case of a dual flow embodiment of such a pump. Sometimes, the rolling bearing can also be intended to be sealed off toward this side via additional sealing rings. During operation, leaks can occur in the region of these sealing planes when the sealing rings become worn or are damaged in some other way. Appropriate repair is necessary. However, this is not always possible or sometimes possible only with great difficulty, for example when the multiphase pump is used under water and is difficult to access.SUMMARY OF THE INVENTION

[0004] The invention is based on the problem of specifying a multiphase pump that is improved compared therewith.

[0005] To solve the problem, the invention provides, in the case of a multiphase pump of the type mentioned at the beginning, that the bearing means are hydrodynamic plain bearings in which the drive spindle and the idler spindle are received via a bearing gap, wherein a feed device for feeding a fluid lubricating medium at a higher pressure than the suction pressure is provided in each bearing gap.

[0006] The multiphase pump according to the invention is distinguished by the fact that the spindle is supported via hydrodynamic plain bearings, i.e. no longer via corresponding rolling bearings. For lubrication of the plain bearings, according to the invention, a liquid lubricating medium is actively introduced or injected at an appropriately high pressure into the bearing gap. As a result, a hydrodynamic pressure is built up in the bearing, which absorbs and seals off the hydraulic force. The pressure at which the lubricating medium is introduced is higher than the suction pressure, i.e. the pressure at which the fluid to be delivered is drawn in, and so, via the lubricating medium, a corresponding lubricating film can build up in the bearing. As a result of this support via hydrodynamic plain bearings that is provided according to the invention, separate sealing elements in the form of the described sealing rings or the like are accordingly not required for bearing sealing, but rather, the support via hydrodynamic plain bearings allows wear-free support in conjunction with sufficient sealing in the bearing region with respect to the spindle housing interior and with respect to the spindle housing exterior. In other words, even a multiphase pump that is difficult to access or is no longer accessible can be operated in a wear-free manner for a long time with regard to the spindle support.

[0007] According to a first variant of the invention, the lubricating medium may be formed by the delivered fluid, which is withdrawn at the pressure side and fed to the plain bearings. According to this configuration, the delivered fluid itself, which is in any case already at a corresponding high outlet pressure, or the liquid phase of the fluid is consequently used in order to realize bearing lubrication, i.e. a liquid portion of the fluid is, as it were, branched off from the pressure chamber or from the pressure side and is conducted to the corresponding plain bearings and introduced into the bearing gap there. Since the fluid or the liquid portion is already at the outlet pressure, which is much higher than the suction pressure, the fluid can consequently be introduced or injected into the bearing gap without the use of an additional pump or the like. The actual pressure at which the fluid is injected is much higher than the suction pressure; it may, but does not have to correspond to the outlet pressure. This configuration of the invention consequently provides, as it were, internal, integrated lubrication of the plain bearing planes without the use of an additional lubricating medium.

[0008] In a development of this configuration of the invention, a channel structure may be provided, via which the fluid is conducted from the pressure side to the bearing gaps. This channel structure may, depending on the configuration, pass through the spindle housing or a cover placed on the spindle housing, i.e. be integrated, as it were, in the housing, this having the advantage that, to realize the channel structure, no additional lines need to be provided. Alternatively, the channel structure can also be realized, at least in part, by separately laid lines. For example, channel portions can be realized in the spindle housing or in a cover placed on the spindle housing, which channel portions lead directly into the respective bearing gap, wherein these channel portions are adjoined by correspondingly laid lines that lead from the pressure side to the corresponding connection points to the channel portions. The lubricating medium injected into the bearing gap is distributed in the bearing gap, wherein the bearing gap is adjoined, on one side, regularly by a region at lower pressure, usually the suction pressure, and to the other side by a region at higher pressure, usually the outlet pressure. The lubricating medium now flows to the low-pressure region, i.e. ultimately the suction region, which, depending on the configuration of the multiphase pump or, respectively, the arrangement of the respective plain bearing, is located in the interior of the spindle housing and, therein, in the region of the fluid inlet, or outside the spindle housing, for example in the region of the attachment of the drive spindle to the drive motor or the like. Flow into the high-pressure region generally does not take place, since the injection pressure is generally somewhat lower than the pressure of the fluid in this high-pressure region or corresponds at most thereto.

[0009] As an alternative to the above-described variant, in which the fluid coming, as it were, from the pressure region is conducted directly to the bearing points, another variant of the invention provides that the lubricating medium is formed by the delivered fluid, which is fed via an external feed line that is connected to the multiphase pump and comes from a separation device. The delivered fluid, i.e. the multiphase mixture, is conducted from the pump first of all to a separation device, which is above ground in the case of underwater use of the multiphase pump. In this separation device, at least the liquid phase is separated from the gas phase. The liquid phase, i.e., for example, the oil or oil / water mixture, is then used as lubricating medium and conducted back to the multiphase pump via a corresponding feed line and injected at the bearing points. To this end, the multiphase pump may again have an integrated channel structure, which is formed or integrated, for example, in the spindle housing or in a housing cover or the like, and to which the feed line is connected via suitable connection means. Within this channel structure, the fluid fed from the outside is then distributed to the bearing points. Alternatively, it is possible here too, of course, for corresponding lines to be laid on the pump side, to which lines the external feed line is connected and via which lines the lubricating medium is distributed to the bearing points. Here too, the fluid itself or a liquid phase of the fluid is consequently used as lubricating medium, i.e., a separate lubricant is again not used. To feed the fluid from the outside, preferably a separate pump is required in this case, via which the corresponding pressure is built up in the fluid, such that the latter can be injected at the desired pressure into the bearing gap as long as the fluid is not yet under a sufficient pressure.

[0010] Such a separate lubricating medium can, however, likewise be used. In a further variant of the invention, the lubricating medium may be a lubricant, in particular an oil, which is conducted from a lubricant reservoir to the plain bearings. This lubricant reservoir is external to the multiphase pump, i.e. it is connected via an external feed line connected to the multiphase pump. Located in this lubricant reservoir is, for example, the oil that is injected into the bearing gaps. For feeding, a separate pump is required here too, in order to introduce the lubricant or, respectively, oil at the correspondingly high injection pressure into the bearing gap. Again, an integrated channel structure can be provided at the multiphase pump, i.e. distribution channels integrated in the spindle housing or in a housing cover, etc., wherein the external feed line is connected to this channel structure. Alternatively, it is also possible for corresponding feed lines to be provided at the multiphase pump, which are connected to the external feed line and via which the lubricant or, respectively, oil is then distributed. Even if a small amount of the separate lubricant can pass into the fluid to be delivered, this amount is negligible, and therefore does not change the properties of the fluid.

[0011] In a development of the invention, provision may be made for each plain bearing to be formed via a bearing bushing, wherein the lubricating medium is able to be fed either via a radial feed channel, which runs through the spindle housing and leads out at a radial opening in the bearing bushing. Alternatively, the lubricating medium can also be feedable axially out of a volume which is delimited between the spindle housing via a housing cover and in which the lubricating medium is present at the higher pressure. Each plain bearing is thus formed via a bearing bushing which has a cylindrical outer bearing seat with which it is received in a corresponding receptacle in the spindle housing or in a housing cover, etc. The respective bearing gap is formed, for the spindle passing through, at the inner circumference. The feed into this bearing gap can now take place in different ways. On the one hand, the bearing bushing itself may be provided with at least one radial opening, which in turn communicates with a radial feed channel that leads out at the opening in the bearing bushing. Via this radial feed channel, the lubricating medium that is under increased pressure is radially fed and is injected via the opening radially into the bearing gap, where it is distributed to both sides. As described, the higher outlet pressure is present on one side of the bearing gap and the lower suction pressure is present on the other side, wherein the lubricating medium injected radially, for example substantially centrally with respect to the length of the bearing gap, is distributed to both sides in the bearing gap. While, toward the outlet pressure side, the lubricating medium is held back via the fluid present there at the outlet pressure, the lubricating medium can flow toward the suction side out of the bearing gap, wherein there is a continuous refeed of lubricating medium via the radial injection. Alternatively, it is conceivable for the lubricating medium to also be conducted axially from a volume, in which the lubricating medium is present at a correspondingly higher pressure, into the bearing gap, which it then flows through to the other side, i.e. the suction region or, respectively, the region at lower pressure. Such a volume can be delimited, for example, via a cover, wherein the fluid to be delivered, for example, is present at its outlet pressure in this volume. Via this, hydraulic thrust compensation is realized, via which one or both idler spindles, which are axially movable per se, while the drive spindle is axially fixed in position, are axially supported, i.e. a supporting pressure is built up there, which prevents an excessive axial movement of the or each idler spindle. This fluid that is under correspondingly high pressure is used at the same time as a lubricating medium in that it is pressed or, respectively, flows axially into the bearing gap, resulting from its high pressure. After passing through the bearing gap, it passes into the suction region and is delivered again.

[0012] In this case, it is conceivable, depending on the configuration of the multiphase pump, for the drive spindle and the at least one idler spindle to be supplied on one side via a radially fed lubricating medium and on the other side via an axially fed lubricating medium in the respective bearing gap.

[0013] In one development of the invention, provision may be made for at least the or each bearing bushing which supports the drive spindle or the idler spindle in the region of the pressure side to have an annular groove which is provided at the inner circumference and leads into an axially extending outlet channel that communicates with a pump region in which there is a lower pressure than the outlet pressure. This variant relates to the bearing bushings which serve to support the spindle ends that are located next to the pressure region, i.e. next to the pressure outlet of the spindle housing. Bearing bushings that are arranged in this position are supplied with the lubricating medium via the respective radial opening, i.e. the lubricating medium is injected radially into the bearing gap. From there, it is distributed, as described, to both sides, wherein it cannot flow into the pressure region, i.e. the interior of the spindle housing, since the high outlet pressure prevails there. Via the annular groove, which is provided according to the invention and is provided at the inner circumference of the bearing bushing in the region of the bushing end that faces the pressure region, a pressure recess is realized, such that the lubricating medium can flow counter to the outlet pressure into the recess, from which, i.e. the annular groove, it flows into the axial outlet channel and from the latter into a pump region that adjoins toward the other side and exhibits a lower pressure, i.e. a region where, as it were, the suction pressure is applied. Such an annular groove is not absolutely necessary in bearing bushings that support the respective other ends of the spindles, since the lubricating medium is introduced preferably axially into the bearing gap there and flows through the latter. At the same time, however, the radial injection can also be provided on this side.

[0014] With regard to the specific configuration of the multiphase pump, two variants are conceivable. It may be a single flow pump, which has one inlet into the spindle housing and one outlet out of the spindle housing. Alternatively, it may also be a dual flow pump, in which both the inlet spindle and the outlet spindle have two spindle portions which work in opposite directions to one another, which work on a common outlet out of the spindle housing, but to which separate inlets are assigned. Independently thereof, each of the spindles is mounted via two plain bearings in the region of the respective spindle ends.

[0015] The drive spindle itself leads out of the spindle housing with a shaft portion and is sealed off via a sealant from the spindle housing or a cover placed on the spindle housing. This region, i.e. the spindle feedthrough through the housing, is the only region in which corresponding sealants need to be provided in the multiphase pump according to the invention. Usually, the drive spindle has a corresponding, cylindrical spindle region with which it is received in a corresponding bore of a housing cover. In this region, a throttle gap to be sealed is usually formed, wherein, for example, an additional sealing ring or a plurality of sealing rings may be connected axially downstream of this region, or seal cartridges or the like, since it is also possible for specific separate bearing planes or magnetic couplings or the like to be provided in this region.

[0016] The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of the disclosure. For a better understanding of the invention, its operating advantages, specific objects attained by its use, reference should be had to the drawings and descriptive matter in which there are illustrated and described preferred embodiments of the invention.BRIEF DESCRIPTION OF THE DRAWING

[0017] In the drawings:

[0018] FIG. 1 shows a basic illustration, in section, of a first embodiment of a multiphase pump according to the invention,

[0019] FIG. 2 shows a basic illustration, in section, of a bearing bushing for forming a hydrodynamic plain bearing for a spindle of the multiphase pump from FIG. 1,

[0020] FIG. 3 shows an enlarged partial view of the multiphase pump from FIG. 1 in the region of the pressure side,

[0021] FIG. 4 shows an enlarged partial view of the multiphase pump from FIG. 1 in the region of the suction side,

[0022] FIG. 5 shows a basic illustration, in section, of a second embodiment of a multiphase pump according to the invention in the form of a dual flow pump,

[0023] FIG. 6 shows an enlarged partial view of the bearing region of a spindle of the multiphase pump from FIG. 5, and

[0024] FIG. 7 shows a basic illustration, in section, of a third embodiment of a multiphase pump according to the invention.DETAILED DESCRIPTION OF THE INVENTION

[0025] FIG. 1 shows a basic illustration of a multiphase pump 1 according to the invention in a sectional view. The multiphase pump 1 comprises a spindle housing 2, which is received in an external housing 3 on which an inlet connection piece 4 and an outlet connection piece 5 for a fluid to be delivered, for example in the form of an oil / gas mixture, are provided. Received in the spindle housing 2 is a spindle packet 6, comprising a drive spindle 7, which leads with a shaft portion 8 out of the spindle housing 2 and out of the external housing 3 in order to be connected to a drive motor, and at least one idler spindle 9, wherein it is also possible for two such idler spindles to be provided. The drive spindle 7 and the idler spindles 9 each have a spindle profile, wherein the spindle profiles mesh with one another. The idler spindle 9 is in this case conjointly driven by the axially positionally fixed drive spindle 7, it is not itself axially positionally fixed, and so can move slightly axially.

[0026] The spindle housing 2 is closed, on one side, the pressure side D, where the fluid is thus present and discharged at the high outlet pressure, via a cover 10 that has been screwed onto the external housing 3 and which is followed by a further bearing cover 11, in which the shaft portion 8 is supported via a suitable rolling bearing 12. Provided on the outer side is a further cover 13, via which a volume 14 is delimited in which, as will be described below, the fluid to be delivered is present at the outlet pressure in order to form, on this side, hydraulic thrust compensation via which the idler spindle 9, which, as described, is not axially positionally fixed, is axially supported.

[0027] Both the drive spindle 7 and the idler spindle 9 are supported at both ends via respective hydrodynamic plain bearings 15, 16 and 17, 18, respectively, wherein each plain bearing 15, 16, 17, 18 is formed via a bearing bushing 19, 20, 21, 22 through which the drive spindle 7 and the idler spindle 9 pass with a corresponding bearing portion. Between the inner wall of each respective bearing sleeve 19-22 and the outer circumference of the respective bearing portion of the drive spindle 7 and the idler spindle 9, a narrow bearing gap is formed, into which a lubricating medium is injected under increased pressure in order, in this way, to form a hydrodynamic lubricating film via which the drive spindle 7 and the idler spindle 9 are supported. In order to make this possible, a corresponding channel structure is provided, which is realized via suitable channel portions that are formed integrally in the spindle housing 2 and optionally in the external housing 3 or a cover 10. This channel structure makes it possible to branch off fluid that is under the outlet pressure, or a liquid phase thereof, from the pressure side D, i.e. ultimately the outlet of the spindle housing 2, and to feed it to the bearing bushings 19, 20, via which the two spindles are supported on the pressure side D, and also to the two bearing bushings 21, 22 which are located on the other side and via which the two spindles are supported on the suction side S.

[0028] FIG. 2 shows an example of a bearing bushing, wherein in this case, by way of example, the bearing bushing 20 is shown, which will also be discussed below with reference to FIG. 3. The design is identical with regard to the bearing bushing 19; the two bearing bushing 21, 22 may be embodied somewhat differently.

[0029] The bearing bushing 20 (as stated, the following information also applies in particular with regard to the bearing bushing 19) is a hollow-cylindrical component, which has an outer bearing seat 23 by way of which the bearing bushing 20 fits in a corresponding bearing seat of the spindle housing 2. The axial position is defined by a stop collar 24. Via the inner wall 25, the above-described bearing gap is defined.

[0030] A radial opening 26 is provided, at which a corresponding channel portion of the described channel structure opens out such that, via this opening 26, a lubricating medium that is under a corresponding pressure, in the example shown the delivered fluid that is withdrawn at the outlet of the spindle housing 2, or the liquid phase, can be injected radially into the bearing gap. This injected lubricating medium is distributed in the bearing gap to both sides, as FIG. 2 shows. To the left-hand side, the lubricating medium can flow away readily, since this side, which is next to the cover 10, is adjoined by a region in which the suction pressure pS prevails. On the opposite side, i.e. toward the interior of the spindle housing 2, the outlet pressure pA prevails. In order nevertheless to also allow fluid to flow to this side, an encircling annular groove 27 is formed at the inner circumference 25 and leads into an axial outlet channel 28 that is in turn open toward the low-pressure side at the suction pressure pS. This makes it possible to form a pressure recess on the side, facing toward the spindle interior, of the respective bearing bushing, into which the fluid fed via the opening 26 can flow.

[0031] The two bearing bushings 21, 22 that are arranged on the opposite side of the spindle do not require such a radial opening 26 since they are supplied axially with the fluid which is present in the volume 14 and is present, as described, at the outlet pressure, this being discussed below.

[0032] FIG. 3 shows an enlarged partial view of the multiphase pump 1 in the pressure region D. What is shown is the bearing bushing 19, via which the drive spindle 7 is supported, and the bearing bushing 20, via which the idler spindle 9 is supported. Corresponding flow arrows are indicated in relation to the bearing bushing 20. Partially illustrated is a part of the channel structure 29, with which the pressurized fluid is fed out of the pressure region D, said fluid being injected via the opening 26 into the bearing gap 30. In this region, the channel structure 29 can run for example radially through the external housing 3 and / or the spindle housing 2. It is distributed, as illustrated by the larger flow arrows P1, to the left and flows into the low-pressure region, which is also designated S here for the sake of simplicity, i.e. the suction region. As the smaller flow arrows P2 show, a certain part also flows in the direction of the pressure region D; it passes into the radial groove 27, which forms a recess, and via the outlet channel 28 again into the suction region S. In this way, the corresponding bearing pressure can be built up on this side. The structure of the support via hydrodynamic bearings is, of course, the same in the bearing gap of the bearing bushing 19.

[0033] FIG. 4 shows a partial view of the other side of the multiphase pump 1. Shown here are the two opposite ends of the drive spindle 7 and of the idler spindle 9, which are supported via the bearing bushings 21, 22 in the region of the suction side S. As described, this region is closed via the cover 13; via the latter, the volume 14 is formed in which the outlet pressure prevails, i.e. there is, again, as it were, a pressure region D here. Here too, the flow arrows are indicated with regard to the bearing bushing 22. Here too, the flow arrows P1 show the fluid flow, although this runs only axially through the bearing gap 31 there, i.e. the lubricating medium, i.e. the fluid under the outlet pressure, is introduced into the bearing gap 31 axially from the right-hand end of the latter and flows out at the left-hand end into the suction region S, where it is delivered further again.

[0034] In this way, support via integrated hydrodynamic, wear-free bearings can be realized via the integrated channel structure with which a part of the fluid or of the liquid phase is withdrawn at the outlet pressure pA from the outlet of the spindle housing 2 and is conducted to the bearing points or, respectively, the bearing gaps.

[0035] FIG. 5 shows an embodiment of a multiphase pump 1 according to the invention, which is embodied as a dual flow screw spindle pump. It again comprises a drive spindle 7, which is guided with its shaft portion 8 out of the pump housing, where a drive motor is intended to be connected. Also provided is an idler spindle 9, which meshes with the drive spindle 7. Each of the two spindles has two spindle profile portions, which run in opposite directions for each spindle, however. This has the result that, in the present case, there are two suction sides S, which are realized at the ends in the spindle housing 2, which, here too, is enclosed by an external housing 3, and a central pressure side D, in which the two opposite spindle portions of the spindles 6, 7 work. The structure of a such a dual flow multiphase pump 1 is known in principle.

[0036] Provided here are two terminal covers 10, via which the spindle housing 2 is respectively closed and which have been screwed onto the external housing 3. Placed on each of the covers 10 is a further cover 13, via which the respective terminal axial housing closure is realized. In these corresponding volumes 32, a low pressure prevails in each case, which corresponds ultimately to the suction pressure or inlet pressure. These are collection spaces in which any leakage fluid is collected.

[0037] Here too, the ends, on both sides, of the respective spindle 6, 7 are supported via corresponding hydrodynamic plain bearings 15, 16, 17, 18, which are realized in the form of corresponding bearing bushings 19, 20, 21, 22.

[0038] Here too, as indicated by the arrows P3, a lubricating medium, again preferably the fluid under the outlet pressure pA that is withdrawn from the pressure region D, is fed radially into the respective bearing gap of the bearing bushing 19–22 in order to form the hydrodynamic lubricating film there.

[0039] In this regard, FIG. 6 illustrates an enlarged partial view which shows the bearing bushing 19. What is shown is the cover 10, through which a channel portion 33 of a corresponding channel structure 29 runs, wherein, of course, such a channel portion 33 is also provided on the other pump side. The fluid injected radially via the latter, see the arrows P3, then runs through the opening 26 in the bearing bushing 19 and is distributed to both sides. In this case, it can be distributed to both sides since there is a respective suction region S, i.e. a region at low pressure, on both sides of the bearing gap 29. The fluid flowing away to the left is then delivered via the spindle packet 4, and the fluid flowing away to the right is collected in the respective volume 32 and from there is delivered via a return line (not shown in more detail) back into the regular suction region.

[0040] It should be noted that – synonymously for the configuration according to FIGS. 1 to 4 as well – the individual bearing bushings 19, 20 and 21, 22, respectively, arranged on a respective side may, but do not have to, each have a separate lubricant feed. Rather, it is also conceivable for them to communicate with one another such that lubricating medium fed via one bearing bushing is also supplied the other bearing bushing.

[0041] Although FIG. 5 shows a dual flow multiphase pump without a transmission, it is alternatively also conceivable to arrange a transmission on the left-hand side according to the illustration in FIG. 5 instead of the cover 13 provided there, via which transmission the drive spindle 7 is coupled to the idler spindle 9, wherein, of course, this transmission is likewise covered in an imprinted manner via a suitable transmission cover.

[0042] Finally, FIG. 7 shows a further embodiment of a multiphase pump 1 according to the invention, which, in terms of its structure, is comparable with the multiphase pump from FIG. 1. Provided again is a spindle housing 2 and an external housing 3, wherein a spindle packet 6 having a drive spindle 7 and an idler spindle 9 is again provided in the spindle housing 2. Here too, the drive spindle 7 is supported by plain bearings via two bearing bushings 19, 21 and the idler spindle 9 is supported by plain bearings via two bearing bushings 20, 22. For the structure and the other design features, including with respect the bearing bushings, etc., reference is made to the information provided for FIG. 1.

[0043] In contrast to the configuration according to FIG. 1, in which the supply of the bearing gap of the hydrodynamic plain bearings takes place, as it were, from the multiphase pump 1 itself, after a part of the delivered fluid delivered at the outlet pressure pA from the spindle housing 2, or of the liquid phase, is branched off and is conducted via the channel structure to the bearing gaps and injected there, in the configuration according to FIG. 7, an external supply with a lubricating medium is provided. In the basic illustration according to FIG. 7, a separation device 34 is provided, which is arranged outside the multiphase pump 1 and to which the fluid, for example an oil / gas mixture, delivered by the multiphase pump 1 and withdrawn via the outlet connection piece 5, is fed, this taking place via a feed line 35. In the separation device 34, the mixture is separated into a liquid phase and a gaseous phase, wherein the liquid phase, or a part thereof, is received for example in a tank 36. From this tank 36, optionally via a pump 37 shown here, the fluid, i.e. the lubricating medium, is initially withdrawn via a line 38 and is then fed via a specific feed line 39 to the volume 14, out of which it flows axially through the bearing gap of the two adjacent bearing bushings 21, 22, as already described with reference to FIG. 4, and is also conducted via the feed lines 40 to the bearing bushings 19, 20, where it is injected radially into the respective bearing gap. In this case, a supply with the lubricating medium thus takes place from the outside, wherein the lubricating medium has again been taken from the delivered fluid, but, as stated, externally in the separation device 34.

[0044] As an alternative to the configuration according to FIG. 7, it is also possible, as lubricating medium, for a separate lubricating medium, for example an oil, to be fed, which does not originate or has not been separated from the delivered fluid. It may thus be an additional, separate lubricating medium, which is fed from a suitable tank via a pump. The basic structure of the supply with the lubricating medium corresponds to the one described in FIG. 7, apart from the feed line 35, which would not be required in this case. Instead of the separation device 34, a corresponding supply device having a corresponding lubricating medium reservoir together with a pump would thus be provided in this configuration.

[0045] All the embodiments have in common that no separate sealing means in the form of sealing rings in the region of the spindle bearings need to be provided in the interior of the pump housing, since support and sealing take place only via the hydrodynamic plain bearings and the injected lubricating medium. Only the drive shaft 7 needs to be supported suitably with its shaft portion 8 and to be sealed off via corresponding sealants with respect to the actual spindle housing 2 or the external housing 3 or the terminal cover 10, wherein, in this regard, different, well-known sealants such as standard seals, sealing cassettes or the like can be used.

[0046] While specific embodiments of the invention have been shown and described in detail to illustrate the inventive principles, it will be understood that the invention may be embodied otherwise without departing from such principles.

Claims

1. A multiphase pump of the screw spindle pump type, comprising a spindle housing with a spindle packet, received therein, comprising a drive spindle and at least one idler spindle meshing therewith, via which spindle packet a fluid to be delivered is able to be delivered from a suction side, at which the fluid is under a suction pressure, to a pressure side, at which the fluid is under an increased outlet pressure, wherein the drive spindle and the idler spindle are each mounted rotatably in the spindle housing via bearing means, wherein the bearing means are hydrodynamic plain bearings in which the drive spindle and the idler spindle are received via a bearing gap, wherein a feed device for feeding a fluid lubricating medium at a higher pressure than the suction pressure is provided in each bearing gap.

2. The multiphase pump according to claim 1, wherein the lubricating medium is formed by the delivered fluid, which is withdrawn at the pressure side and fed to the plain bearings.

3. The multiphase pump according to claim 2, wherein a channel structure is provided, via which the fluid is conducted from the pressure side to the bearing gaps.

4. The multiphase pump according to claim 1, wherein the lubricating medium is formed by the delivered fluid, which is fed via an external feed line that is connected to the multiphase pump and comes from a separation device.

5. The multiphase pump according to claim 1, wherein the lubricating medium is a lubricant, in particular an oil, which is conducted from a lubricant reservoir to the plain bearings.

6. The multiphase pump according to claim 5, wherein the lubricant reservoir is connected via an external feed line that is connected to the multiphase pump.

7. The multiphase pump according to claim 1, wherein each plain bearing is formed via a bearing bushing, wherein the lubricating medium is able to be fed either via a radial feed channel, which runs through the spindle housing or a housing cover and leads out at a radial opening in the bearing bushing, or is able to be fed axially out of a volume which is delimited between the spindle housing via a housing cover and in which the lubricating medium is present at the higher pressure.

8. The multiphase pump according to claim 7, wherein at least the or each bearing bushing which supports the drive spindle or the idler spindle in the region of the pressure side has an annular groove which is provided at the inner circumference and leads into an axially extending outlet channel that communicates with a pump region in which there is a lower pressure than the outlet pressure.

9. The multiphase pump according to claim 1, wherein it is a single flow or a dual flow pump, wherein the drive spindle and the idler spindle are each supported via two plain bearings.

10. The multiphase pump according to claim 1, wherein the drive spindle leads out of the spindle housing with a shaft portion and is sealed off via a sealant from the spindle housing or a cover placed on the spindle housing.

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