EP3108145B2 - Rotary machine and method for heat exchange in a rotary machine - Google Patents

Description

The invention relates to a rotary machine for conveying a fluid and a method for heat exchange in such a machine according to the preamble of the independent patent claim of the respective category.

Rotary machines, such as pumps, are used to convey fluid media in a wide variety of technological fields. In the hydrocarbon processing industry, pumps play an important role in the entire processing chain, which usually starts at the oil or gas field, and often have to work under technically very demanding conditions. When pumping crude oil, for example, it is possible for the medium to be pumped to be at very high temperatures of up to 200°C. Such high temperatures place great demands on the pump and in particular on the mechanical seals in such a pump.

Mechanical seals are commonly used to seal the shaft which carries the impeller of the pump and which is driven by the drive unit such as a motor. These seals are intended to prevent the fluid to be pumped from escaping on or along the shaft. Typically, mechanical seals are designed as face or slide ring seals, which include a stator and a rotor. The rotor is connected to the shaft in a rotationally fixed manner, while the stator is fixed with respect to the pump housing in such a way that it is secured against rotation. During the rotation of the shaft, the rotor and the stator slide against each other, which results in a high mechanical load on these parts. For the proper operation of such mechanical seals, it is necessary for these seals not to be subject to excessive thermal loads in the operating state. Therefore, the mechanical seals must be cooled, especially in the case of such fluids that are pumped at high temperatures. Too high a temperature in the area of the mechanical seal can lead to material degradation on the sliding surfaces or other parts of the seal, damage to the secondary seals, unwanted phase transitions in the fluid to be pumped or thermally induced changes in the shaft, e.g. B. Bends.

Conversely, in applications in which the fluid to be conveyed is very cold, for example in cryogenics when conveying liquefied gases, the mechanical seals must be warmed up or heated in order to ensure proper operation.

Depending on the application, it must therefore be ensured that the mechanical seal or its surroundings are cooled or heated, i.e. kept in the correct temperature range via heat exchange.

Two possibilities are known in the state of the art for this heat exchange at mechanical seals, ie the dissipation or the supply of heat. In the first method, a heat exchange jacket is provided in the vicinity of the mechanical seal, which is a cooling jacket for dissipating heat or a heating jacket for supplying heat, depending on the application. This jacket includes a cavity that surrounds the mechanical seal in the form of an annular space, for example, and through which a fluid heat carrier flows, which supplies or dissipates the heat. The cavity has no connection to the space in which the mechanical seal is arranged, so that there is no direct contact between the heat transfer medium and the mechanical seal. With this type of heat dissipation or heat supply, external auxiliary systems, e.g. B. used an external pump to promote the fluid heat transfer medium in the cavity of the heat exchange jacket and to circulate the heat transfer medium.

The second option for heat exchange is based on direct contact of the mechanical seal with a fluid heat transfer medium and is usually referred to as "flushing". In this case, the mechanical seal, or at least parts thereof, is directly subjected to a fluid heat transfer medium in order to withdraw heat from it or to supply heat to it. For this type of heat exchange, it is known to circulate the fluid heat carrier in a closed circuit, which then comprises an external heat exchanger, to which the heat carrier releases the heat absorbed by the mechanical seal (cooling of the seal), or to which the heat carrier transfers the absorbs heat, which it supplies to the mechanical seal (heating of the seal). The circulation of the heat carrier is driven by an external pump. As an alternative or in addition to the external pump, an impeller can also be provided, e.g. on the mechanical seal, which is driven by the rotation of the shaft and circulates the fluid heat carrier.

As an alternative to the closed flushing systems, it is also known to use open systems in which the heat transfer medium is not circulated in a closed circuit but is taken from a source and, after passing through the pump, is discharged, for example a sewage disposal system. With these open systems, there is usually no need for an external heat exchanger.

It is also known to provide pumps with two separate cooling systems that work independently of one another, one of which works with a cooling jacket and one of which is designed as a flushing system. The two systems can be operated with different heat carriers. However, such solutions are very complex in terms of apparatus, cost-intensive and usually require a large amount of space.

Proceeding from this state of the art, it is therefore an object of the invention to propose a rotary machine with a new heat exchange system for a mechanical seal that is simple in terms of apparatus and provides efficient cooling or heating even at high temperature loads due to the heat or cold of the fluid to be conveyed of the mechanical seal. In particular, the rotary machine should be suitable for high-temperature applications in which the fluid to be pumped is very hot. Furthermore, it is an object of the invention to propose a corresponding method for the heat exchange in a rotary machine.

The objects of the invention that solve this problem are characterized by the features of the independent patent claims of the respective category.

According to the invention, a rotary machine for conveying a fluid according to claim 1 is proposed.

According to the invention, it is therefore proposed to combine a heat exchange system that works according to the flushing principle with a heat exchange system that works with a jacket to form a common overall system in which only one fluid heat carrier is circulated, the circulation of which is driven by the rotary machine itself . This heat exchange system thus combines the advantages of two heat exchange systems without the need for external circulation devices such as external pumps. This results in a very simple, compact and efficient solution in terms of apparatus, with which even large amounts of heat can be reliably removed from the area of the mechanical seal (cooling) or fed to this area (heating).

Due to the high efficiency of the heat exchange, the rotary machine according to the invention is also particularly suitable for high-temperature applications in which the fluid to be conveyed can have temperatures of up to 200° C. or more.

In a preferred exemplary embodiment, the rotating machine is designed as a pump, with the drive unit comprising a motor which is arranged in a motor housing.

It is advantageous if the impeller is arranged in a pump housing which is connected to the motor housing to form an overall housing, so that the pump including the motor is enclosed in a single housing. This compact design, which is closed off from the outside, allows the pump to be operated even under difficult environmental conditions.

Depending on the application, it can be advantageous if the rotary machine works in a vertical arrangement. It is then preferred that the drive unit is arranged above the pump unit in the normal position of use, because then the drive unit is not loaded by the weight of the impeller.

A further advantageous measure with regard to cooling, lubricating and protecting the drive unit, e.g. against the fluid to be pumped, is if the motor housing is filled with a sealing liquid during operation.

The sealing liquid is then particularly preferably provided as the fluid heat carrier.

In terms of apparatus, it is advantageous if the impeller for circulating the heat carrier is driven by the drive unit and is preferably provided on the side of the drive unit facing away from the impeller.

A preferred use of the rotary machine is for conveying hot fluids, the temperature of which is at least 150°C.

According to the invention, a method according to claim 9 is also proposed for heat exchange in a rotary machine for conveying a fluid.

We ask you to delete paragraphs 21, 29 and 64.

The advantages of this method correspond to those that have already been explained in connection with the rotary machine according to the invention.

In a preferred embodiment, the common heat exchange system is a refrigeration system.

The method is particularly suitable when the rotary machine is a pump, the drive unit comprising a motor which is arranged in a motor housing, the fluid heat carrier being used as a sealing liquid with which the motor housing is filled and the impeller preferably being driven by the drive unit is driven.

It is an advantageous measure if the fluid heat carrier is a water-based liquid, because these liquids are generally inexpensive, have sufficient heat capacity and are not harmful to the environment. In particular, mixtures of water and glycol are suitable as a fluid heat carrier.

The method according to the invention is particularly suitable for high-temperature applications in which the fluid to be pumped has a temperature of at least 150°C.

Further advantageous measures and refinements of the invention result from the dependent claims.

Fig. 1:

eine schematische Darstellung eines Ausführungsbeispiels einer erfindungsgemässen Rotationsmaschine ausgestaltet als Pumpe, und

Fig.2:

eine schematische, teilweise geschnitte Darstellung einer mechanischen Dichtung mit Komponenten des Wärmetauschsystems.

The invention is explained in more detail below both in terms of apparatus and in terms of process technology using an exemplary embodiment and using the drawing. In the schematic drawing show, partly in section:

Figure 1:

a schematic representation of an embodiment of a rotary machine according to the invention designed as a pump, and

Fig.2:

a schematic, partially sectioned representation of a mechanical seal with components of the heat exchange system.

In the following description of a rotary machine according to the invention and a method according to the invention for heat exchange, reference is made, by way of example, to the application that is particularly important in practice, that the rotary machine is a pump. However, it goes without saying that the invention is not limited to such cases, but also includes all other rotary machines in which a mechanical seal is provided for shaft sealing. The rotary machine can also be a compressor, a turbine or a generator, for example.

Furthermore, with regard to the heat exchange with an exemplary character, it is assumed that the heat exchange is cooling, in which heat is therefore withdrawn from the system. It goes without saying that the invention also includes applications in the same way in which the heat exchange is heating, ie applications in which heat is supplied to the system.

1 1 shows, in a very schematic representation, a rotary machine which is designed as a pump and is denoted overall by the reference numeral 1. The pump 1 includes a drive unit 2 with a motor 21 which is arranged in a motor housing 22 and is designed here as an electric motor. The motor 21 has a motor shaft 25 which is the rotor of the electric motor.

The pump 1 also includes a pump unit 3 with a pump housing 32 in which an impeller 31 is provided for conveying a fluid. The impeller 31 is arranged on a shaft 5 which is connected to the motor shaft 25 by means of a coupling 9 and is thus driven by the motor 21 and rotated about its longitudinal axis A ( 2 ) is relocated.

The motor housing 22 and the pump housing 32 are firmly connected to one another, for example screwed together with several screws, and thus form an overall housing 4 for the drive unit 2 and the pump unit 3
The shaft 5 and the motor shaft 25 are mounted in a number of axial bearings 7 and radial bearings 8 in a manner known per se.

The pump unit 3 also includes an inlet 33, through which the fluid to be pumped is sucked into the pump housing 32 by the action of the impeller 31, and an outlet 34 through which the fluid to be pumped is pushed out.

To seal the shaft 5, two mechanical seals 6 are provided in the pump, namely a first one, which seals the shaft 5 at the boundary between the pump unit 3 and the drive unit 2, so that the fluid to be pumped cannot flow along the shaft 5 into the drive unit 2 and a second, which is provided below the impeller 31 according to the illustration and which prevents the fluid to be pumped from penetrating along the shaft 5 into a bearing space 35 which is provided below the impeller 31 according to the illustration and in which one of the radial bearings 8 is arranged.

The exemplary embodiment of the rotary machine according to the invention explained here is a multi-stage process pump for high-temperature applications in which the fluid to be pumped has very high temperatures of, for example, 150° C., 180° C., 200° C. or even more. Such high temperatures can occur, for example, in natural gas or oil production, because there are oil fields in which the oil is present at temperatures below 200°C.

In particular, the embodiment described here is designed as a subsea (subsea) pump that is mounted on the seabed and operates there, z. B. for oil or gas production. Especially with such applications, an extremely compact design and the highest possible operational safety and reliability are essential.

As is usual with subsea applications, the Pump 1 designed in a vertical arrangement with the drive unit 2 on top, ie in 1 the pump 1 is shown in its usual position of use. The motor housing 22 of the drive unit 2 is filled with a sealing liquid 23 in a manner known per se, which is used to cool the mechanical and electrical components of the motor 21 and for lubrication. The storage space 35 arranged below the impeller 31 is also filled with the sealing liquid 23 .

In 2 one of the mechanical seals 6 is shown in a highly simplified and schematic manner. Mechanical seals per se are well known to those skilled in the art and therefore do not require any further explanation here. For this reason and because it is sufficient for understanding, in 2 many details such as the fixations of the parts of the seal 6 or secondary seals, z. B. O-rings, not shown.

Typically, mechanical seals are designed as face or slide ring seals, which include a stator 61 and a rotor 62 . The rotor is connected to the shaft 5 in a rotationally fixed manner, while the stator 61 is fixed in relation to the overall housing 4 or in relation to the pump housing 32 in such a way that it is secured against rotation. Thus, during the rotation of the shaft 5, the rotor 62 and the stator 61 slide against each other.

It is essential for the proper functioning of the mechanical seals 6 that the seal 6 does not become too hot (in the case of high-temperature applications) or too cold (in the case of low-temperature applications). For this purpose, according to the invention, a new method for the heat exchange with the mechanical seal 6 is proposed, which is now based on the in the 1 and 2 illustrated embodiment is explained.

A first heat exchange system 41 and a second heat exchange system 42 are provided—here cooling systems—which are connected to form a common heat exchange system 40 . This integrated heat exchange system 40 is used to cool the mechanical seals 6.

The first heat exchange system 41 for cooling the mechanical seal 6 is a so-called flushing system, in which the mechanical seal 6 or at least parts thereof is or are acted upon directly by a fluid heat carrier—here a coolant. Like this 2 shows, the mechanical seal 6 is arranged in a sealing space 63, which is designed, for example, as an annular space and surrounds the shaft 5. The heat transfer medium is introduced into this sealing space 63 through an inlet opening 64 . Furthermore, an outlet opening (not shown) is provided on the sealing space 63 through which the heat carrier can leave the sealing space 63 again. The outlet opening is arranged, for example, rotated by 45° or by 90° with respect to the longitudinal axis A in relation to the inlet opening 64 . During operation of the pump 1, the sealing chamber 63 is essentially completely filled with the heat carrier, i.e. the same amount of coolant (heat carrier) flows through the inlet opening 64 into the sealing chamber 63 as flows out of the sealing chamber 63 through the outlet opening. The heat exchange - here the cooling - thus takes place through the direct contact of the heat transfer medium with the mechanical seal 6, in which the heat transfer medium extracts heat from the seal 6 and thus cools it.

The second heat exchange system 42 for cooling the mechanical seal 6 includes a heat exchange jacket 421, which is a cooling jacket 421 in the present exemplary embodiment. With this type of heat exchange, there is no direct physical contact between the mechanical seal 6 and the heat transfer medium, in this case the coolant. The cooling jacket 421 includes a cavity 422 which is designed, for example, as an annular space and surrounds the entire shaft 5 . An inlet 423 is provided, through which the heat transfer medium is introduced into the cavity 422, and an outlet 424, through which the heat transfer medium leaves the cavity 422. During operation, the cavity 422 is completely filled with the heat carrier that is circulated through the cavity 422 . With this type of heat exchange or cooling, there is no direct physical contact between the heat transfer medium and the mechanical seal 6.

Like this particular out 1 As can be seen, the cooling jacket 421 is in each case arranged on the hotter side of the mechanical seal 6, ie on the side of the seal 6 in which the higher temperature prevails in the operating state. The pump housing 32 is in the operating state, with the exception of the storage space 35 with the fluid to be pumped - so for example with the hot oil - filled. In particular, the fluid to be conveyed in the vicinity of the seal 6 is also cooled by the cooling jacket 421 , ie for example also in the gap 51 which leads to the seal 6 . This cooling of the fluid to be conveyed in the immediate vicinity of the mechanical seal 6 also significantly reduces the heat input into the seal 6 by the fluid to be conveyed, which corresponds to a cooling of the seal 6 .

According to the invention, the first heat exchange system 41 and the second heat exchange system 42 are now connected to form the integrated common heat exchange system 40 . The consequence of this is that there must be a common fluid heat transfer medium for the common heat exchange system 40 . While different fluid heat carriers could also be used for these two separate systems in the case of separate first and second heat exchange systems, the solution according to the invention requires a common fluid heat carrier which, for example, can be the same heat carrier as that of the first or second heat exchange system.

The sealing liquid 23 , which is also used for lubricating and cooling the motor 21 or the drive unit 2 , is particularly preferably provided as the fluid heat carrier for the common heat exchange system 40 . This has the advantage that only a single liquid has to be provided, which is used both as a sealing liquid 23 and as a fluid heat carrier for the heat exchange system 40 . Especially for subsea applications, this measure has a very positive effect in terms of the equipment required.

Water-based liquids such as a mixture of water and glycol are particularly suitable as a fluid heat transfer medium.

Like this in 1 is shown, the common heat exchange system 40 is designed as a closed system, ie as a cooling system or a cooling circuit, in which the fluid heat transfer medium is circulated. An impeller 44 is provided for the circulation of the heat transfer medium, which is arranged on the motor shaft 25 and is thus driven by the drive unit 2, specifically by the rotation of the motor shaft 25 of the motor 21.

The impeller 44 conveys the heat transfer medium via a main line 45 to a heat exchanger 43 in which the heat transfer medium releases the heat absorbed at the mechanical seal 6 or in the drive unit 2 or in the storage space 35 and is thereby cooled. A plurality of lines now branch off from the main line 45 downstream of the heat exchanger 43, first a first line 451, through which the heat carrier enters the motor housing 22, as symbolically indicated by the arrow on the line 451. The heat carrier fills the motor housing and serves as a sealing liquid 23.

A second line 452 branches off from the main line 45 further downstream, through which the heat transfer medium reaches the cooling system for the mechanical seal 6 . The second line 452 in turn branches into a branch leading to the inlet 423 ( 2 ) of the cooling jacket 421, and into a branch leading to the inlet port 64 of the seal chamber 63. From the outlet opening (not shown) from the sealing chamber 63 and the outlet 424 of the cavity 422 of the cooling jacket 421, the fluid heat carrier reaches the return line 46 via respective lines, which are combined to form line 461.

Finally, the main line 45 merges into a third line 453, through which the heat carrier reaches the cooling system for the lower mechanical seal 6 according to the illustration. The third line 453 in turn branches into a branch leading to the inlet 423 ( 2 ) of the cooling jacket 421, and into a branch leading to the inlet port 64 of the seal chamber 63. In the exemplary embodiment described here, this sealing space 63 is connected to the storage space 35 so that the heat transfer medium can also reach the storage space 35 via the same line that leads to the inlet opening 64 of the sealing space 63 . From the outlet opening from the sealing chamber 63 and the outlet 424 of the cavity 422 of the cooling jacket 421, the fluid heat carrier reaches the return line 46 via respective lines, which are combined to form line 462.

The heat carrier returns through the return line 46 to the area of the impeller 44, which drives the circulation of the heat carrier in the closed cooling circuit. The heat transfer medium introduced into the motor housing 22 via the first line 451 is also recirculated by the action of the impeller 44, as indicated by the arrow with reference number 463.

The impeller 44 for circulating the fluid heat carrier is preferably on the side of the drive unit 2 or provided on the side of the motor 21 facing away from the impeller 31 .

In this way, the first heat exchange system 41 for the mechanical seals 6 and the second heat exchange system 42 for the mechanical seals 6 are connected to form a common heat exchange system 40, which thus forms an integral heat exchange system for the mechanical seals 6. At the same time, the common heat exchange system 40 also serves to supply the motor housing with the sealing liquid 23, which is identical to the fluid heat transfer medium.

As is customary, particularly in subsea applications or in subsea pumps, the sealing liquid 23 in the motor housing 22 is kept under a higher pressure than the fluid to be pumped in the pump housing 32. The pressure of the sealing liquid 23 in the motor housing 22 is, for example, 20-25 bar higher than the pressure in the pump housing 32.

The method according to the invention and the rotary machine according to the invention are suitable for a large number of applications. They are particularly suitable for high-temperature applications and especially for those in the subsea area. Designed as a pump, the rotary machine according to the invention can be used to pump oil, gas, seawater or so-called "produced water". The pump can be designed as a single-phase, multi-phase or hybrid pump with the impellers correspondingly adapted to it. Both configurations as single-stage as well as multi-stage pumps are possible.

In particular for undersea applications, the solution proposed according to the invention, thanks to its integrated heat exchange system, represents an efficient, reliable, simple to use and compact option for cooling or heating mechanical seals.

As already mentioned, a vertical arrangement is preferred in an embodiment of the pump as a submersible pump, in which the drive unit 2 above the Pump unit 3 is arranged. Of course, horizontal arrangements are also possible, in which the drive unit 2 and the pump unit 3 are arranged next to one another. Such an arrangement is often preferred when the pump is not used in submarine operation but, for example, on land, or on ships or on drilling platforms.

As already mentioned, the rotary machine according to the invention and the method according to the invention are also suitable for low-temperature applications, for example for pumping liquid gases in cryogenics. In such applications, the mechanical seals are warmed or heated by the heat carrier. The heat exchanger 43 then serves to supply heat to the heat transfer medium, which heat is then transported to the mechanical seals in the same way. In such applications, the heat exchange jacket of the second heat exchange system is then arranged on the colder side of the mechanical seal 6, ie on that side of the mechanical seal 6 which faces the lower temperature range in the operating state.

Claims (13)

1. A rotary machine for conveying a fluid, having a drive unit (2) for driving a shaft (5), having an impeller (31) arranged at the shaft (5) for conveying the fluid, having at least one mechanical seal (6) arranged in a sealing space (63) for sealing the shaft (5), having a first and a second heat exchange system (41; 42) for cooling or for heating the mechanical seal (6); wherein the first heat exchange system (41) is configured for the direct application of a fluid heat carrier at the mechanical seal (6) and the second heat exchange system (42) comprises a heat exchange jacket (421), wherein the heat exchange jacket (421) comprises a hollow space (422) which can be flowed through by a fluid heat carrier without direct contact with the mechanical seal (6), wherein the rotary machine is configured as a subsea pump, and the first and the second heat exchange systems (41; 42) form a common heat exchange system (40) which is configured as a closed system in which a common fluid heat carrier can be circulated, wherein a fan wheel (44) is provided for the circulation of the fluid heat carrier in the heat exchange system (40), characterized in that the fan wheel (44) conveys the heat carrier via a main line (45) to a heat exchanger (43), wherein the common heat exchange system (40) comprises a line (452) which branches away from the main line (45) downstream of the heat exchanger (43) and branches into a branch which leads to an inlet (423) of the heat exchange jacket (421) as well as into a branch which leads to an inlet opening (64) of the sealing space (63), wherein the heat exchange system (40) further comprises a return line (46) and the return line (46) is connected via respective lines to an outlet opening of the sealing space (63) and to an outlet (424) of the hollow space (422), and wherein the heat carrier again arrives in the region of the fan wheel (44) through the return line (46).
2. A rotary machine in accordance with clam 1, which is configured as a pump, wherein the drive unit (2) comprises a motor (21) which is arranged in a motor housing (22).
3. A rotary machine in accordance with claim 2, in which the impeller (31) is arranged in a pump housing (32) which is connected to the motor housing (22) to form a common housing (4).
4. A rotary machine in accordance with any one of the preceding claims, in which the drive unit (2) is arranged above the pump unit (3) in the normal position of use.
5. A rotary machine in accordance with any one of the claims 2 to 4, in which the motor housing (22) is filled with a sealing liquid (23) in the operating state.
6. A rotary machine in accordance with claim 5, in which the sealing liquid (23) is provided as the fluid heat carrier.
7. A rotary machine in accordance with any one of the preceding claims, wherein the fan wheel (44) is driven for the circulation of the heat carrier by the drive unit (2) and is preferably provided at the side of the drive unit (2) disposed remote from the impeller (31).
8. Use of a rotary machine in accordance with any one of the preceding claims, for the conveyance of hot fluids whose temperature amounts to at least 150°C.
9. A method for the heat exchange in a rotary machine for conveying a fluid, the rotary machine having a drive unit (2) for driving a shaft (5), an impeller (31) arranged at the shaft (5) for conveying the fluid, as well as at least one mechanical seal (6) arranged in a sealing space (63) for sealing the shaft (5), in which method the mechanical seal (6) is cooled or heated with a first and a second heat exchange system (41; 42), wherein the mechanical seal (6) is directly applied with a fluid heat carrier by means of the first heat exchange system (41); and a heat exchange jacket (421) comprises a hollow space (422), which hollow space (422) is flowed through by a fluid heat carrier without direct contact with the mechanical seal (6) in the second heat exchange system (42), wherein the rotary machine is configured as a subsea pump, and the first and the second heat exchange systems (41; 42) are connected to a common heat exchange system (40) which is configured as a closed system in which a common fluid heat carrier is circulated and the fluid heat carrier is circulated in the heat exchange system by a fan wheel (44), characterized in that the fan wheel (44) conveys the heat carrier via a main line (45) to a heat exchanger (43), wherein the common heat exchange system (40) comprises a line (452) which branches away from the main line (45) downstream of the heat exchanger (43) and branches into a branch which leads to an inlet (423) of the heat exchange jacket (421) as well as into a branch which leads to an inlet opening (64) of the sealing space (63), wherein the heat exchange system (40) further comprises a return line (46) and the return line (46) is connected via respective lines to an outlet opening of the sealing space (63) and to an outlet (424) of the hollow space (422), and wherein the heat carrier again arrives in the region of the fan wheel (44) through the return line (46).
10. A method in accordance with claim 9, wherein the common heat exchange system is a cooling system.
11. A method in accordance with one of the claims 9 or 10, wherein the rotary machine is a pump, wherein the drive unit (2) comprises a motor (21) which is arranged in a motor housing (22), wherein the fluid heat carrier is used as a sealing liquid (23) with which the motor housing (22) is filled and wherein the fan wheel (44) is preferably driven by the drive unit (2).
12. A method in accordance with any one of the claims 9 to 11, wherein the fluid heat carrier is a water-based liquid.
13. A method in accordance with any one of the claims 9 to 12, wherein the fluid to be conveyed has a temperature of at least 150°C.

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