EP2626564B1 - Pump, separation device for a pump, and a rotor shaft for a pump - Google Patents

Description

The invention relates to a pump for conveying a pump fluid comprising an ingredient, a separation device and a rotor shaft for a pump according to the preamble of claims 1, 5 and 6. In the prior art it is a well-known measure to use the rotating parts of pumps to lubricate the pumping medium itself, which has the obvious advantage that no special lubricant has to be made available for these lubricating applications. This can be of particular advantage if the provision of the lubricant, for example for the lubrication of a rotating pump rotor shaft carrying a pump rotor, is only possible with particular difficulties. Another advantage is that a shaft seal can be dispensed with on the non-drive side by using a self-lubricating or product-lubricated bearing, since the shaft no longer has to be led out to the atmosphere. In addition to a large number of other applications, pumps for pumping multi-phase mixtures, such as for pumping crude oil, are prominent examples. Such pumps often have to be in very poorly accessible locations are operated, often many hundreds of meters, even up to a few thousand meters below the sea surface, where the pumps must be operated reliably under extreme conditions for considerable periods of time.

It goes without saying that the pumps should require as little maintenance as possible in such or other poorly accessible locations and, in particular, should have as little need as possible for externally supplied operating materials, such as, for example, special lubricating oil. As far as the necessary lubrication of such pumps is concerned, the use of the medium to be pumped as a lubricant is the method of choice, since the medium to be pumped is of course available in the pump anyway, in practically any quantities, so that no lubricant has to be provided separately from the outside and the lubricant does not have to be replaced after a certain period of operation because fresh and unused lubricant is always available from the medium to be pumped itself.

From the WO 91/12412 A1 it is known to filter part of a pump fluid with a filter and to use the filtered pump fluid as a lubricant.

From the DE 1 653 738 it is known to filter part of a fuel contaminated with a solid and to feed it back into the gaps of the pump at a higher pressure so that the solid cannot penetrate into the gaps.

From the CH 672 005 A5 a self-priming centrifugal pump with a cell flushing system and an associated separation chamber is known. With a fixed surface F and a collecting nozzle D for the cell rinsing, gas can be removed from the conveying medium.

From the US-RE-26740 a pump with a separate centrifugal separator is known, in which the cleaned liquid from the centrifugal separator can be fed into the pump as a lubricant.

From the EP 0 447 106 A2 A cooling pump for a reactor is known in which particles from the liquid can be thrown from a liquid for cooling the bearings by means of a rotating separating element into a recess ("annular deadend cavity").

But also in other applications where the pumps are easily accessible, for example, the use of the medium to be pumped as a lubricant has great advantages, because no separate lubricant has to be made available, which makes the pumps more cost-effective in operation and often simpler in terms of equipment power. A large part of the maintenance work associated with the lubrication and the downtimes are eliminated, i.e. the maintenance intervals are extended because, not least, the regular replacement of the corresponding lubricant is no longer necessary.

A problem that has not been adequately solved so far occurs, however, when pumping such pumping media, for example with a multiphase mixture which, in addition to crude oil, also contains natural gas and often also water and, above all, harmful solids such as sand. The additional Indeed, ingredients are often rather harmful for lubricating applications. The expert immediately understands that, for example, hard ingredients such as sand can have a massive negative effect on lubrication. For example, if a lubricant contaminated with sand is used to lubricate a rotor shaft of an impeller, the sand in the lubricant can cause considerable damage to the parts to be lubricated because the hard grains of sand damage the surfaces of the components to be lubricated, which are often made of relatively soft metal which can ultimately lead to failure of the pump.

It is therefore known in the prior art to particularly harden those parts which are lubricated with a lubricant contaminated with sand, for example, so that the sand contained in the lubricant cannot damage the surfaces, or to at least reduce the wear of the corresponding parts reduce the fact that justifiable long downtimes, i.e. economically justifiable maintenance intervals, can be achieved.

The hardening of the corresponding parts, e.g. the rotor shaft of an impeller of the pump or the static or rotating counterparts and bearing components that form the rotor shaft bearing is of course a measure that is on the one hand very complex and therefore expensive and ultimately does not actually solve the problem because even the Hardened parts cannot withstand the abrasive load over time, e.g. from sand contained in the lubricant. Another point is that, for example, the width of the lubricant gap between the rotating and / or static parts of the bearings often cannot be reduced to the desired level, because otherwise the harmful influence of hard, non-compressible ingredients such as sand would be so great that premature wear and tear of the corresponding bearings would be inevitable. Because the bearing gaps cannot be optimally adjusted due to such restrictions, the running smoothness of the stored parts can be negatively influenced, and by If the lubricant gaps are not set optimally, harmful vibrations can occur in the operating state, which can ultimately also lead to premature wear.

However, not only solid ingredients but also liquid or gaseous ingredients can negatively affect the lubricating behavior because, for example, the viscosity, i.e. the viscosity of the pump fluid used as a lubricant is poorly or not at all suitable for use as a lubricant.

The object of the invention is therefore to propose a pump for conveying a pump fluid comprising an ingredient, in which the medium to be pumped can be used simultaneously to lubricate rotating parts of the pump, in particular to lubricate the rotor shaft of the pump rotor, the prior art known harmful effects of the ingredients on the lubrication process are largely avoided. Another object of the invention is to provide a separation device and a rotor shaft for such a pump.

The subject matter of the invention which achieves this object is characterized by the features of claims 1, 5 and 6. The dependent claims relate to particularly advantageous embodiments of the invention.

The invention thus relates to a pump for conveying a pump fluid comprising an ingredient, wherein in the operating state the pump fluid provided under an inlet pressure on a low pressure side of the pump can be conveyed to a high pressure side of the pump by means of a pump rotor rotatably mounted in a pump stator about an axis of rotation. The pump rotor is designed and arranged in a shaft bearing via a rotor shaft that between the rotor shaft and the shaft bearing a lubricating film from a lubricating fluid formed from the pump fluid can be formed in a lubricating ring gap. According to the invention, a separation device rotating with the rotor shaft is provided on the rotor shaft, with which a predeterminable amount of the ingredient can be separated from the pump fluid by means of a centrifugal force in order to provide the lubricating fluid.

It is therefore essential for the invention that a separation device is provided on the rotor shaft with which a predeterminable amount of the ingredient, often sand in practice, can be separated from the pump fluid by means of centrifugal force in the operating state. For this purpose, the pump fluid to be conveyed by the pump, for example crude oil loaded with sand, which is conveyed from a raw source by the pump to a collecting store, can be conveyed from the high pressure side of the pump into a chamber of the separation device that rotates with the rotor axis at the end of the rotor axis . The pump fluid in the rotating separation device is exposed to the centrifugal forces acting there due to the rotation and is conveyed to the outside, for example into an outer annular chamber of the separation device. Due to the higher density of the sand compared to the liquid portion of the pump fluid, the sand will accumulate under the centrifugal force at the outer edge of the annular chamber of the separation device, so that a phase of the pump fluid that is highly enriched with sand is formed at the outer edge of the annular chamber a corresponding discharge opening is preferably discharged back to the low-pressure side of the pump and is not used for lubrication, for example the rotor shaft. The pumping fluid that is to be used for the lubrication is withdrawn from a further inner diameter of the annular chamber of the separation device, where a phase of the pumping fluid with a low sand concentration has accumulated.

It goes without saying that in this way, of course, fluid ingredients, such as, for example, liquid or viscous ingredients of high density, which the pump fluid contains, can also be used with the separation device according to the invention in a manner analogous to e.g. Let the sand separate so that, for example, the portion of the pump fluid that is to be used for lubrication has a predetermined suitable viscosity, which is not too high, for example, because more viscous portions can be removed with the separation device.

So that a flow or a ratio of the flows of the pump fluid heavily loaded with the constituent through the discharge opening on the one hand and the pump fluid largely cleaned of the constituent flowing through the annular gap between the rotor shaft and shaft bearing on the other hand is reliably ensured, a suitable geometry of the flowed through cross-sections.

Thus, the present invention makes it possible for the first time to separate not only solid ingredients but also liquid or gaseous ingredients that negatively affect the lubricating behavior from the pump fluid to be conveyed in such a way that a phase of the pump fluid that has been sufficiently purified of ingredients is provided can be used to lubricate rotating parts of the pump, the harmful effects of the ingredients on the lubrication process known from the prior art being largely avoided. Depending on the exact composition and consistency of the pump fluid or the ingredients, mixing or dissolution phenomena, for example, can also be relevant, which can further positively influence the separation process. For example, it is possible for gas fractions to be dissolved in higher viscoses and / or in fluid constituents of higher density or, for example, enclosed in the form of bubbles and thus also to be separated off by the separation device according to the invention. Of course Other processes known per se can also contribute to the separation device not only being able to separate components with a higher density but also those with a lower density, because they are carried along by the components with a higher density.

As already mentioned, in an exemplary embodiment which is particularly preferred in practice for supplying the pump fluid comprising the ingredient, in particular sand, the separation device is connected to the high-pressure side of the pump via a supply line. The feed line can, for example, be an integral part of the pump housing, in particular a bore or bore-like connection opening running in the pump housing or pump stator, or the feed line can also be implemented as a separate line that connects the high-pressure side with the separation chamber.

In particular, the separation device, which rotates with the rotor shaft about the axis of rotation, comprises an outer annular chamber, on which annular chamber an essentially tangentially oriented separation opening is provided for separating the constituents, the separation opening being particularly preferably connected to the low-pressure side of the pump via a separation line for discharging a solid is. Of course, the separation line can also be an integral part of the pump housing, in particular a bore or bore-like connection opening running in the pump housing or pump stator, or the separation line can also be implemented by a separate line that connects the separation opening of the separation chamber with the low-pressure side of the Pump connects, or connects to some other point with low pressure, the ingredient, so in practice often sand or another liquid or gaseous fluid component of the pump fluid, preferably, but not necessary as explained above, a higher density than the phase of the pump fluid used as the lubricating fluid.

For example, so that the shaft bearing in which the rotor shaft of the pump is mounted can be optimally supplied with the phase of the pump fluid that has been cleaned of the constituent for lubrication, the lubricating ring gap is flow-connected to the separation device, in particular by means of a lubricant opening, in such a way that it is at least partially freed from the constituents Lubricating fluid can be supplied to the lubricating ring gap for lubricating the shaft bearing via the lubricant opening.

In a special exemplary embodiment, an additional lubricant line can be provided in such a way that a predeterminable amount of lubricating fluid can be discharged from the separation device and can be used to feed a further lubrication point of the pump. Of course, the lubricant line can also be an integral part of the pump housing, in particular a bore or bore-like connection opening running in the pump housing or pump stator, or the lubricant line can also be implemented by a separate line that connects the separation device of the separation chamber with the further lubrication point in the pump connects.

Depending on the application and exemplary embodiment, the separation device can either be detachably connected to the rotor shaft, wherein the separation device can in particular be configured as a separation disk that can be screwed to the rotor shaft. It is of course also possible that the separation device is an integral part of the rotor shaft, wherein the separation device can in particular be a separation disk integrally connected to the rotor shaft.

The invention further relates to a separation device for a pump according to the invention, wherein the separation device is particularly preferably designed as a separation disk that can be screwed to a rotor shaft of the pump.

In practice, the separation device comprises in particular an outer annular chamber, on which annular chamber a preferably essentially tangentially oriented separation opening is provided for separating an ingredient, in particular sand.

Finally, the invention also relates to a rotor shaft for a pump with a separation device of the present invention, the separation device being particularly preferably releasably connectable to the rotor shaft.

Fig. 1a

ein Ausführungsbeispiel einer erfindungsgemässen Pumpe mit Separationsscheibe;

Fig. 1b

die Separationsscheibe der Pumpe gemäss Fig. 1a im Detail;

Fig. 1c

das Wellenlager der Pumpe gemäss Fig. 1a im Detail;

Fig. 2

eine andere Variante eines Wellenlagers einer erfindungsgemässen Pumpe.

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

Fig. 1a

an embodiment of a pump according to the invention with a separation disk;

Figure 1b

the separation disk of the pump according to Fig. 1a in detail;

Figure 1c

the shaft bearing of the pump according to Fig. 1a in detail;

Fig. 2

another variant of a shaft bearing of a pump according to the invention.

Based on Fig. 1a A particularly preferred exemplary embodiment of a pump according to the invention with a separation device in the form of a separation disk will be discussed below, wherein Figure 1b the separation disc and Figure 1c the construction of the shaft bearing of the pump according to Fig. 1a show a little more in detail.

The pump according to the invention, which is designated in its entirety with the reference number 1 in the following, is used quite generally and in particular in the special exemplary embodiment Fig. 1a for conveying a pump fluid 2 comprising an ingredient 21. The ingredient 21 in the example of FIG Figures 1a to 1c is essentially sand, which acts as an impurity in the pump fluid 2 is present in intolerable quantities. The pump fluid 2 here is crude oil, which is available at an inlet pressure P1 on a low-pressure side LP of the pump 1 and, in the operating state, is conveyed to a high-pressure side HP of the pump 1 by means of a pump rotor 4 rotatably mounted in a pump stator 3 around an axis of rotation A according to the arrow P . The pump rotor 4 is designed in such a way and arranged via a rotor shaft 5 in a shaft bearing 6 that a lubricating film 20 from a lubricating fluid 200 formed from the pump fluid 2 can be formed between the rotor shaft 5 and the shaft bearing 6 in a lubricating ring gap 21. According to the invention, a separation device 7 is provided on the rotor shaft 5, with which a predeterminable amount of the ingredient 21 can be separated from the pump fluid 2 by means of a centrifugal force in order to provide the lubricating fluid 200 in the operating state.

As in Fig. 1a Shown schematically, the separation device 7, which is designed as a separation disk screwed to the rotor shaft 5 of the pump 1 with screws 70, via a supply line 8 with the high pressure side HP of the Pump 1 connected. The separation disk is covered by a cover D through which the pump fluid 2 is supplied to the separation disk.

According to Fig. 1a or. Figure 1b who have favourited the separation disc of the Fig. 1a shows again somewhat more precisely in detail, the separation disk rotating with the rotor shaft 5 about the axis of rotation A comprises an outer annular chamber 71, an essentially tangentially oriented separation opening 72 being provided on the annular chamber 71 for separating the ingredient 21. The separation opening 72 is connected to the low-pressure side LP of the pump 1 via a separation line 9 for discharging the solids 21, that is to say in the present example for discharging the sand enriched in petroleum. The sand has a higher density than the lubricating fluid 200 which, as will be explained further below, is finally used to lubricate the rotor shaft 5.

So that the lubricating fluid 200 can be provided for lubricating the rotor shaft 5 in the shaft bearing 6, the lubricating ring gap 21 is flow-connected to the separation device 7 by means of a lubricant opening 22 in such a way that the lubricating fluid 200 from which the sand is at least partially freed is fed to the lubricating ring gap 21 for lubricating the shaft bearing 6 via the Lubricant opening 22 can be supplied.

Furthermore, a lubricant line 10 is provided in such a way that a predeterminable amount of lubricating fluid 200 can be discharged from the separation disk, in particular for feeding additional lubricant points of the pump 1, which additional lubricant points are not explicitly shown for reasons of clarity. It is even possible that the lubricating fluid 200 branched off via the lubricant line 10 is used to lubricate further system parts that are outside the pump 1 or are not part of the pump 1.

As in Figure 1c The separation device 7, that is to say here the separation disk, is shown schematically somewhat more clearly Fig. 1a as already briefly mentioned, releasably connected to the rotor shaft 5.

In another exemplary embodiment, however, it is of course also possible for the separation device 7 to be an integral part of the rotor shaft 5 and, for example, schematically on the basis of FIG Fig. 2 shown, the separation device 7 is in particular a separation disk integrally connected to the rotor shaft 5. The embodiment according to Fig. 2 differs from the in Figure 1c illustrated embodiment only in that the separation disk is integrally connected to the rotor shaft 5 and, moreover, no additional lubricant line 10 is provided because in the example of Fig. 2 the Lubricant 200 only for lubricating the rotor shaft 5, and is not required at any other point.

In all the exemplary embodiments shown here in the figures, the separation line 9 is designed as an integral component in the pump stator 3, but can also be routed as a separate additional separation line, for example on the outside of the housing of the pump.

It goes without saying that all of the exemplary embodiments of the invention described above are only to be understood as exemplary or exemplary and that the invention particularly, but not exclusively, includes all suitable combinations of the exemplary embodiments described.

Claims (12)

1. Separation device (7) for separating a pump fluid (2) delivered by a pump (1), the pump fluid comprising a constituent (21); wherein the separation device (7) is attachable to a rotor shaft (5) which is mounted in the pump (1) so as to be rotatable about an axis of rotation (A) in a shaft bearing (6), characterized in that in the operating state of the pump (1) the separation device (7) rotates with the rotor shaft (5); that in the operating state of the separation device (7) a predeterminable quantity of the constituent (21) and of a lubricating fluid (200) is separated from the pump fluid (2) by means of a centrifugal force; and that the separation device (7) is adapted and suitably designed to supply the lubricating fluid (200) separated from the pump fluid (2) to a lubricating gap located between the rotor shaft (5) and the shaft bearing (6) of the pump (1).
2. Separation device (7) according to claim 1, wherein the separation device (7) is in the form of a separation disc which can be screwed to the rotor shaft (5) of the pump (1).
3. Separation device (7) according to claim 1, wherein the separation device (7) is an integral part of the rotor shaft (5), or the separation device (7) is in particular a separation disc integrally connected to the rotor shaft (5).
4. Separation device (7) according to one of the preceding claims, wherein the separation device comprises an outer annular chamber (71), on which annular chamber (71) a substantially tangentially oriented separation opening (72) is provided for the separation of the constituent (21), in particular sand.
5. Rotor shaft (5) for a pump (1) for the pumping of pumping fluids (2) comprising a constituent (21), the rotor shaft comprising a separation device (7) according to claims 1-4, wherein

   - the rotor shaft (5) comprises a pump rotor (4); and wherein

   - the rotor shaft (5) is suitably designed to be received by the shaft bearing (6) located in a pump stator (3) of the pump (1); and further

   - the rotor shaft (5) is adapted and suitably designed so that a lubricating fluid (200) formed in the operating state can be fed from the separation device (7) to the lubricating ring gap.
6. Pump (1) for delivering a pump fluid (2) comprising a constituent (21), the pump (1) comprising:

   - a separation device (7) according to claims 1 - 4 and

   - a rotor shaft (5) according to claim 5
   wherein, in the operating state, the pump fluid (2) provided at an inlet pressure (P1) on a low-pressure side (LP) of the pump is supplied by means of a pump rotor (4) rotatable about an axis of rotation (A) mounted to a bearing in a pump stator (3) to a high pressure side (HP) of the pump.
7. Pump (1) according to claim 6, wherein the separation device (7) is connected to the high-pressure side (HP) of the pump via a feed line (8) for feeding the pump fluid (2) comprising the constituent (21) to the separation device (7).
8. Pump (1) according to claim 6, wherein the separation opening (72) for discharging the constituent (21) is connected to the low-pressure side (LP) of the pump via a separation line (9),
9. Pump (1) according to one of claims 6 - 8, whereby the constituent (21) has a higher density than the lubricating fluid (200) and / or the constituent (21) is a solid, in particular sand.
10. Pump (1) according to one of the claims 6 - 9, wherein the lubricating annular gap is connected to the separation device (7) by means of a lubricant opening (22) in such a way that that the lubricating fluid (200) at least partially freed from the constituent (21) can be fed to the lubricating gap for lubricating the shaft bearing (6) via the lubricant opening (22).
11. Pump (1) according to one of claims 6-10, wherein a lubricant line (10) is provided in such a way that a predeterminable amount of lubricating fluid (200) can be supplied from the separation device (7), in particular for feeding a further lubrication point of the pump.
12. Pump (1) according to claim 8, wherein the separator line (9) is formed as an integral component in the pump stator (3).

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