A fluid flow system, and a method of assembling the fluid flow system

Abstract

The present invention relates generally to a fluid flow system comprising a pump, such as for pumping of liquefied gasses from the cargo hold of a ship. The fluid flow system further comprises - a first elongated pipe having a first end and a second end, wherein the first elongated pipe is comprised of a plurality of elongated pipe segments each having a first end and a second end opposite to the first end of the pipe segment, - a motor shaft extending inside the first elongated pipe from a motor to an impeller, - a plurality of spaced apart motor shaft supports having a portion defining a bearing for providing sideways support for the motor shaft wherein each pipe segment comprises one spacer having a plurality of motor shaft supports arranged apart from one another in the longitudinal direction of the first elongated pipe or wherein each pipe segment comprises several spacers each having at least one motor shaft support arranged apart from one another in the longitudinal direction of the first elongated pipe.

Description

[0001] A fluid flow system, and a method of assembling the fluid flow system

[0002] The present invention relates generally to a fluid flow system comprising a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, a first elongated pipe having a first end and a second end, wherein the first elongated pipe is comprised of a plurality of elongated pipe segments each having a first end and a second end opposite to the first end of the pipe segment, a motor at the first elongated pipe end, a pump impeller at the second elongated pipe end, a motor shaft extending inside the first elongated pipe from the motor to the impeller, for rotating the pump impeller, and a plurality of spaced apart motor shaft supports having a portion defining a bearing for providing sideways support for the motor shaft.

[0003] Such as a fluid flow system which can be used for offshore or land-based application, for fluid tanks or inline applications and for a variety of fluids.

[0004] Background of the invention

[0005] Fluid flow systems of the aforementioned type are used both onshore and offshore. In certain applications they are being referred to as deep well pumps. In deep well pumps, the pump, defined by the pump impeller, is arranged in a fluid reservoir below the motor. Deep well pumps may be used for e.g. extracting hydrocarbons from natural deposits, to load or unload cargo tanks, and for conveying fuel from one or more of a fuel tank and cargo tank to an engine. When used on board a ship, the pump impeller is placed close to the bottom of one or more of a fuel tank and cargo tank within the fluid reservoir.

[0006] Deep well pumps may in some cases be used for conveying liquefied gasses such as liquid petroleum gas (LPG), liquefied natural gas (LNG), methane, ethanol, methanol, ammonia, liquefied carbon dioxide (LCO2), and liquefied nitrogen (LiN). As will be understood, deep well pumps generally comprise rotating parts, such as the motor shaft and the impeller, and non-rotating parts, such as the pipes. The deep well pump, including the motor shaft, may extend over long lengths or relatively long lengths, making it essential to control vibrations of the motor shaft. This is usually achieved using motor shaft supports with portions defining bearings. The motor shaft supports are attached to a coaxial elongated first pipe or a coaxial first pipe enclosing or surrounding the motor shaft, also referred to as a support pipe. These shaft supports are conventionally mounted in flanges used for connecting individual segments of the elongated first pipe, whereby the number of bearings is limited to essentially correspond to the number of such flange connections or segments. In such a case, high quality bearings must be used due to the limited number of available motor shaft supports. This leads to high costs and may not fully solve problems relating to controlling the natural frequencies and mode shapes of the system. Especially in high vibration cases, such as when running the motor shaft at high RPM, having a minimal distance between bearings corresponding to the length of the segments of the first pipe may be inadequate.

[0007] Summary of the invention

[0008] In view of the aforementioned problems, associated with the prior art, a first aspect of the present invention relates to an improved fluid flow system comprising one or several spacers having a first and a second end being arranged between the first elongated pipe and the motor shaft, each supporting at least one shaft support with a portion defining at least one bearing for the motor shaft. The first elongated pipe is comprised of several pipe segments serially connected, such as by flange connections. The spacers facilitate the mounting of several motor shaft supports within the length of a pipe segment, either by mounting one spacer having several motor shaft supports in each pipe segment or by mounting several spacers each having at least one motor shaft support within the length of each pipe segment. The spacers thereby allow motor shaft supports to be positioned independently from any features of the first elongated pipe, such as the connections between pipe segments of the first elongated pipe. The spacers thereby facilitate the positioning of several motor shaft supports within a single pipe segment, thereby facilitating a solution to the above-mentioned problems.

[0009] The fluid flow system may be used for cargo operations on a ship, for one or more of fuel supply to an engine, and fuel supply to a generator. The fluid flow system may alternatively be used onshore for one or more of pumping fluids at low temperature and pumping fluids at high pressure.

[0010] The bearings of the motor shaft supports are preferably a plain bearing but use of other bearing types such as one or more of ball-, roller-, liner-, and needle bearings may be foreseen.

[0011] The impeller pump of the fluid flow system may e.g. be a centrifugal pump of any orientation, such as a vertical pump, such as a horizontal pump.

[0012] The spacers are positioned, and optionally fixed, inside the first elongated pipe, to thereby support and position the shaft supports, which in turn provide the sideways support for the motor shaft. Each spacer may comprise several individual spacer units or be a single unit. Having the spacer as a single unit eases assembly of the spacers with the motor shaft supports. Having the spacer be comprised of several spacer units may increase manufacturability and may enable using the same spacer unit components for pipes of different diameters. If the spacer is comprised from spacer units, these units may conveniently be assembled via the motor shaft supports, thereby limiting the number of parts needed. The spacers may have varying lengths, depending on one or more of the length(s) of the pipe segments and the amount of motor shaft supports needed in the first elongated pipe. The spacers may be manufactured as elements separate from the shaft supports and configured with a seat for the shaft supports. The spacers or spacer units may comprise means for securing the motor shaft support to the spacer. The means for seating and / or securing the motor shaft supports to the spacer may be arranged at varying intervals throughout the length of the individual spacers, so as to control and adjust the mode shapes and natural frequencies of the motor shaft. The seats may in other embodiments be arranged at arbitrary points along the length of the spacers.

[0013] The spacers may in a preferred embodiment comprise at least one rail, such as two rails, with each rail being a spacer unit. The rail may be one or more of a bend, welded, bolted, cast and / or extruded profile. The rail material may be selected based on the fluid pumped by the fluid flow system. The rail may have means for one or more of seating and fixing one or several motor shaft supports. The rail may have a central flat surface with two bordering surfaces oriented at an angle to the central flat surface. The bordering surfaces may be flat or curved. The rail may alternatively define a curved surface. The means for securing the one or several motor shaft supports may by way of example be apertures matching apertures on the motor shaft supports, for inserting bolts, pins, screws, rivets or similar means. The apertures on one or more of the spacers and shaft supports may be threaded.

[0014] In this preferred embodiment, the spacers may be confined to a segment of the first elongated pipe, by mounting seating rings in the connections between pipe segments. The seating rings create shelves on at least a part the internal circumference of the first elongated pipe, thereby preventing the spacers from passing these shelves. Thereby, motor shaft supports may be mounted in locations that are dependent on features of the spacers but independent of any features of the first elongated pipe. This effect may alternatively be achieved by fixing the rails to the first elongated pipe such as by a press fit, or fixating means. The fixating means may by way of example be one or more of welding, bolts and adhesives. In this case, a curved or bended profile or curved or bended sheet metal structure can be used, which acts like a spring and limits the relative movement, such as rotation, of the rail to the first elongated pipe.

[0015] The seating rings may be fixed to the inside of the first elongated pipe such as by one or more of a press fit, welding, bolts, adhesives and clamping them in the flanges connecting the pipe segments. It is noted that the movement of the seating ring relative to the first elongated pipe can be limited and controlled by any type of contact between the seating ring and the first elongated pipe. When securing the seating rings by one or more of a press fit, welding and adhesives, the seating rings may be mounted independently of connections between pipe segments.

[0016] The seating rings may rigidly confine the spacers, or the spacers may be able to drift at least translationally in the longitudinal direction of the first elongated pipe between two seating rings. The spacers may be radially confined by the first elongated pipe by an interference, transition, or clearance fit.

[0017] The spacers space the motor shaft supports along the longitudinal direction of the first elongated pipe. The spacers thereby allow the motor shaft supports to be positioned optimally in terms of one or more of number of bearings, natural frequencies and shape modes of the motor shaft.

[0018] The profile may, by way of example, be made by one or more of metal extrusion, polymer extrusion, and bending of sheet metal.

[0019] The profile may be made of one or more of aluminium, steel, titanium, and polyether ether ketone.

[0020] The fit between the spacers and the surrounding first pipe can be either an interference, transition, or clearance fit and may be used to reinforce the pipe against mechanical and thermal loads, such as sloshing and contraction or expansion due to rapid temperature changes.

[0021] The spacers may be tubular structures, extending at least partially around the motor shaft’s circumference. The spacers may alternatively be in the form of threaded bars extending parallel to the motor shaft or in the form of smaller shelves covering at least part of the motor shaft’s circumference.

[0022] The spacers may be fastened to other similar or dissimilar spacers to form longer spacer sections. The spacers can be secured to the first pipe and / or secured to another non-rotating component using methods such as one or more of bolts, pins, screws, welding, spot welding, adhesives, finger joint connections, press-fitting, and threads.

[0023] The spacers may be placed onto the internal surface of the first pipe or there may be a gap between the first pipe and the spacers. Whether the spacers are placed onto the internal surface or with a gap between the first pipe and the spacers may be chosen based on consideration of thermal conductivity between the components and the coefficients of thermal expansion and contraction of the components. For instance, if the components have similar coefficients of thermal expansion and contraction, it may be advantageous to have no gap between the spacers and the first elongated pipe to provide good thermal conductivity and a uniform contraction and expansions of both components. If on the other hand they have dissimilar coefficients of thermal expansion and contraction, it may be advantageous to have a gap between them to accommodate their dissimilar changes during cooling or heating,

[0024] The shaft supports may be seated at one or more of the ends of the spacers and on the spacers using one or more features such as shelves, apertures, threaded apertures, and threaded sections. A shaft support may be seated on one or several spacers. The shaft supports may be mounted to their seatings using one or more methods such as bolts, pins, screws, welding, spot welding, adhesives, finger joint connections, press-fitting, and threads.

[0025] The shaft supports may in one embodiment comprise a first ring intended for being seated onto the spacers with one or several arms extending from the internal surface of the first ring to a second ring with the bearing portion being on the internal surface of the radius of the second ring. In another embodiment, the shaft support may be a single disk with a hole defining the bearing portion of the shaft support, possibly with additional holes for circulating lubricant.

[0026] One or more of the shaft support and the portion defining the bearing may be made from a self-lubricating material such as oil impregnated bronze, various polymers, or a suitable polymer.

[0027] The shaft support and bearing may be manufactured as an integral unit or be made as an assembly. In another embodiment the bearing may be a layer coated onto the shaft support. The shaft support, bearing and spacer may in one embodiment be manufactured as a single integral unit.

[0028] A second elongated pipe coaxial with the first pipe may be provided, where the second pipe defines a fluid flow conduit extending from the pump impeller to the first end of the motor shaft. In another embodiment the second elongated pipe defining a fluid flow conduit is placed alongside the first pipe either in parallel or at an angle to the first pipe. The first pipe may be configured for allowing a portion of the pumped fluid to pass along its length, such as for lubrication of the bearings.

[0029] The disclosed invention allows for seating shaft supports comprising bearings at a distance from one another which may be independent of any features of one or more of the first and of the second elongated pipe, where provided, such as flanges or other assemblies of pipe segments The various components of the fluid flow system will have different mass, heat capacity, thermal conductivity, and thermal expansion, all of which can independently cause issues when loading or unloading fluids that are colder or significantly colder than ambient temperature, such as liquefied gasses. The rapid temperature changes in the pump environment can cause significant thermomechanical loading of the pump system. Especially the support pipe and pump housing are prone to cool at a faster rate than the rotating components inside them, such as the impeller. Concerns about the impeller and the non-rotating components colliding due to thermal contraction of the non-rotating components may be a limiting factor for loading and unloading rate of the transported fluid. The spacers may, by selecting appropriate materials contribute to the total heat capacity of the non-rotating components near the impeller and thus may enable a faster introduction of cold fluids into the pump environment.

[0030] In particular, a preferred embodiment wherein the spacers comprise a tubular structure and forming a lining of the first elongated pipe is particularly advantageous in providing a fast introduction of cold fluids into the pump environment, relative to known prior art.

[0031] The spacers can be made from one or more of metals, polymers, ceramics, composites, functionally graded materials, carbon, graphite, and glass. Especially suitable or specific materials from some of the material groups include:

[0032] • Metals: carbon steel, stainless steel, chrome steel, bronze, phosphor bronze, oil-impregnated bronze, aluminium, brass.

[0033] • Polymers: Plastics such as nylon, PTFE (Polytetrafluoroethylene), UHMWPE (Ultra-High-Molecular-Weight Polyethylene).

[0034] • Composites: A combination of materials like PTFE, POM (Polyoxymethylene), and fiberglass, offering tailored properties for specific applications. Ceramics: Materials such as silicon nitride (Si3N4) or zirconia (ZrO2), hybrid ceramics.

[0035] The shaft supports can be arranged and secured independently of any features of the pipe in which they are placed and can be deployed as preassembled bearing units comprising the spacers and the shaft supports. The shaft supports may also be preassembled with the pipe segments.

[0036] The bearings may in a preferred embodiment be made from or lined with a carbon graphite materials selected from various grades, including resin-impregnated, electrographite, and metal-impregnated types (such as tungsten-, copper-, or antimony-impregnated carbon graphite). These materials typically exhibit a Brinell hardness in the range of 20-60 HB 5 / 62.5, such as 40 HB5 / 62.5; however, depending on the specific composition and processing method, certain grades may achieve hardness values up to 120 HB 5 / 62.5 — or even higher. The final material selection is based on application-specific requirements, including load capacity, temperature resistance, wear performance, chemical compatibility, and self-lubricating properties.

[0037] In a second aspect, the invention relates to a method of assembling the fluid flow system, wherein spacers, with the shaft support seated, are inserted one by one into the first elongated pipe, or into segments thereof. The assembling may comprise inserting a seating ring, bearing, and / or shaft support in the flange of a pipe segment, securing a new pipe segment to the flange connection and inserting the spacer with motor shaft supports into the pipe segment. This method may be repeated until the first pipe is fully assembled. Alternatively, the spacers may be inserted so as to be stacked on top of each other.

[0038] The spacers may also, in one embodiment of the assembling method, be joined to form a larger assembly of several spacers with seated shaft supports which are then inserted one by one into the first elongated pipe or into segments thereof. In a flange connection between two elongated pipe segments, there may be a seating ring or bearing assembly. This can be combined with a spacer into the bearing assembly to form an internal support for the motorshaft and to place the bearings around the rotating shaft.

[0039] In a third aspect, the present invention relates to a method of pumping a fluid, preferably liquefied gas, from a fluid container of a vessel, such as the cargo hold of a ship, the method comprising:

[0040] -providing the system according to the first aspect of the invention; and -activating said system so as to initiate said pumping.

[0041] In a fourth aspect, the present invention relates to use of the system according to the first aspect or the method of assembling such system according to the second aspect, for pumping of a fluid, preferably liquefied gas, from a fluid container of a vessel, such as the cargo hold of a ship.

[0042] It is to be understood, that any of the first and second aspect may be combined with other aspects of the invention.

[0043] Brief description of the drawings

[0044] Fig. 1 is a cross-sectional side view of a prior art fluid flow system

[0045] Fig. 2a shows an embodiment of the fluid flow system of the present invention with the system placed in conjunction with a cargo hold, with fig 2b showing an enlarged partial view of the system.

[0046] Fig. 3a is a view similar to fig, 2a, shows a cargo hold, such as the cargo tank of a ship, where a cargo pipe is placed parallel to the first elongated pipe of fig. 2a. fig 3b is an enlarged view of the system similar to figure 2b. Figs. 4a and 4b shows an embodiment of a spacer where a shaft support is seated and secured in one end of the spacer and its cross section. Fig 4c show an embodiment where the spacer, shaft support, and bearing are an integral unit

[0047] Figs. 5a and 5b shows an embodiment of the spacer with several seating places for shaft supports which may be secured to the spacer and its cross section,

[0048] Fig. 6a shows an embodiment of the spacer unit with several seating places for shaft supports which may be secured to the spacer unit. Fig. 6b show an isometric view of four spacer units arranged as to constitute a single spacer and fig. 6c show a top view of the spacer unit,

[0049] Figs. 7a and 7b shows an embodiment of the spacer comprised of thread bars each defining a spacer unit and its cross section.

[0050] Fig. 8 shows an example of an assembly method of the elongated pipe with the spacers and shaft supports.

[0051] Fig. 9a shows a spacer comprised of two spacer units in the form of rails with a plurality of motor shaft supports mounted in the spacer and fig 9b shows a section of such a spacer.

[0052] Figs. 10a and 10b show a side and top view of a section of a spacer similar to the spacer of fig. 9a.

[0053] Detailed description The invention will now be explained in more detail below by reference to preferred embodiments.

[0054] Fig. 1 shows a conventional deep well fluid flow system 1 which may be applied in a ship’s hold (not shown), where motor shaft supports 29 and bearings 4 are arranged at each connecting flange 26 for connecting individual segments 6’ of the first elongated pipe 6 to each other. The motor shaft 8 may as shown be an assembly of shaft segments.

[0055] Figs. 2a-3b show distinct embodiments of the claimed fluid flow system 1 including a pump, such as for discharge of liquefied gasses from the cargo hold of a ship, comprising a first elongated pipe 6 having a first end 5 and a second end 7. The first elongated pipe 6 is comprised of pipe segments 6’ each having a first and a second end opposite to each other. The fluid flow system 1 further comprises a motor 9 at the first end of the first elongated pipe 5, a pump impeller 10 at the second end 7 of the first elongated pipe. The motor 9 is connected to the impeller 10 by a rotationally driven motor shaft 8, driven for rotation by the motor 9, extending inside the first pipe 6 from the motor 9 to the impeller 10. A plurality of spaced apart shaft supports 29 with bearings 4 are mounted inside the first elongated pipe for supporting the motor shaft 8 in the radial direction along its length. The motor shaft supports 29 are mounted to one or several spacers 2 arranged between the first elongated pipe 6 and the motor shaft 8, each supporting at least one of the shaft supports 29. Each pipe segment 6’ contains either one spacer 2 supporting several motor shaft supports 29 or several spacers 2 supporting at least one motor shaft support 29. The motor shaft 8 may, as shown in fig. 1 be an assembly of individual segments (not shown in figs. 2 and 3). Fluid may also be discharged at the first end 5 of the of the first elongated pipe 6.

[0056] The motor 9 may be a motor assembly comprising the motor 9, which comprises a stator and a rotor, a bearing house, a static seal and motor housing which in some embodiments might be integrated to be a part of the bearing house.

[0057] In fig. 2a the fluid flow system 1 is shown having a majority of its length inside the cargo tank 16 of a ship in the cargo cavity 18 such as being for its most part submerged in the cargo cavity 18. The fluid flow system 1 shown in this figure comprises a second pipe 12. The second pipe 12 is also termed a cargo pipe and is used for pumping a fluid, such as a liquefied gas, via the pump impeller 10. The second pipe 12 is arranged coaxial to the motor shaft 8 and the first pipe 6 and inside the first pipe 6. The first pipe 6 and second pipe 12 may be assembled from a plurality of segments having connecting flanges 26, 30. Both the first pipe 6 and the second pipe 12 may be used for pumping the fluid or only one of them may be used for pumping the fluid. Alternatively, the two pipes may be used for pumping dissimilar fluids.

[0058] In figs. 3a and 3b, the second pipe 12 is arranged alongside the first pipe 6. A sealing component 20 is arranged between the impeller housing 14 and the first pipe 6 holding the spacers 2, shaft supports 29, and bearings 4 to keep these components separated from the pumped fluid.

[0059] The spacers 2, which may each be an assembly of several spacer units 3 (see figs. 6, 7, 9, or 10), may be placed inside the first pipe 6 to define a lining of the first elongated pipe 6. The shaft supports 29 with bearings 4 are distributed along the length of the motor shaft 8. The motor shaft supports 29 are seated in the spacers 2 at a distance that is less than the distance between the connecting flanges 26 of the segments 6’ of the first elongated pipe 6. The seatings 24 may be formed as shelves on the inside of the spacers 2, apertures in the spacers 2 or at the end of the spacers 2. The impeller 10 is used for pumping the fluid during operation of the system. The impeller 10 is driven by the rotating the motor shaft 8 which is coupled to the motor 9. The impeller 10 is arranged at the end of the motor shaft 8 inside an impeller housing 14. Figs. 4-7 show various embodiments of the spacers 2 and spacer units 3. In fig. 4 the spacer 2 is a single cylindrical tube with a means of securing a shaft support 22 thereto, using e.g. pins, bolts, screws or adhesives. The shaft support seat 24 is at the end of the spacer 2. The securing means on the bearing 28 is shown on the shaft support 29 and is in this embodiment holes for securing means such as pins, bolts and screws. In the embodiment shown on fig 4c the spacer 2, shaft support 29 and bearing 4 form an integral unit or is an integral unit.

[0060] The spacers 2 may, by way of example, have a length (I) of 200-2000 mm, such as 250-300 mm, such as 350-450 mm, such as 700-800 mm, such as 1000-1500 mm.

[0061] The spacers 2 may, by way of example, have an outer diameter (0) of 5-500 mm, such as 5-150 mm.

[0062] Fig. 6 shows an embodiment wherein the spacer 2 and the shaft support 29 is an assembly of several spacer units 3 which collectively support one or several shaft supports 29. Each spacer unit 3 only covering a part of the internal circumference of the first elongated pipe 6.

[0063] In fig. 6 the spacer 2 has several individual seatings 24 for the shaft supports 29, in the form of shelves on the inside of spacer units 3 and a seat 24 at the end of the spacer units 3. Each seating 24 has a securing means 22 for the shaft support 29 such as pins, screws, bolts, adhesives, welding, or spot welding.

[0064] Figs. 7a and 7b show an embodiment in which the spacer 2 comprises several threaded bars, each defining a spacer unit 3. In this embodiment the shaft support 29 can be seated at an arbitrary position along the length of the spacer 2 and may be secured by internal threads in the shaft support 29. Several shaft supports 29 are seated and secured on the spacer 2. The seating place 24 of the shaft support 29 are in this embodiment continuous along the length of the spacer 2. The length of the spacer 2 in this embodiment may correspond to the length of the first elongated pipe 6 (not shown on this figure).

[0065] The invention also relates to a method of assembling the fluid flow system 1 , as shown in fig. 8, wherein spacers 2 with shaft supports 29 are inserted one by one along arrow A into the first pipe 6, or into a segment 6’ thereof. In the embodiment shown on fig. 8 the spacers 2 are stacked on top of each other. Alternatively, the spacers 2 may be supported in the first pipe 6 at predetermined locations such as by ledges or seating rings (not shown). One or more of the seating rings and ledges may be secured in the connecting flanges 26 of the pipe segments 6’ of the first elongated pipe 6 or secured to the inside of the first elongated pipe 6. The spacers 2 may be secured vertically at the first end 5 of the first elongated pipe 6 or at the corresponding end of the segments 6’.

[0066] Figs 9a and 9b show a preferred embodiment of the spacer 2 wherein the spacer 2 is comprised of two spacer units 3. Each spacer unit 3 comprises a rail. The spacer 2 seats a plurality of motor shaft supports 29 each housing a bearing 4. The motor shaft supports 29 are spaced in the longitudinal direction of the first elongated pipe 6 (not shown on these figures) by the spacer 2. The motor shaft supports 29 are seated in the spacer 2 by screws inserted thorough apertures in the spacer 2 and into matching apertures of the shaft supports 29.

[0067] Figs, 10a and 10b shows a section the same preferred embodiment as shown in figs 9a and 9b viewed from the radial and axial direction of the first elongated pipe 6 (not shown on this figure) respectively. The screws used for seating the motor shaft supports 29 are best seen from fig. 10a. The first elongated pipe 6 may be comprised of a plurality of pipe segments 6’connected by flanges 26. The spacers 2 of figs. 9a-1 Ob may advantageously be confined by seating rings mounted in the flanges 26 connecting the plurality of pipe segments 6’. The seating rings define shelves on the internal circumference of the first elongated pipe 6 which confine each spacer 2 to a single pipe segment 6’. The spacer 2 has a plurality of motor shaft supports 29, and this arrangement enables the mounting of several motor shaft supports 29 within the length of a single pipe segment 6’.

[0068] As may be seen from the drawings in general, all embodiments of the invention facilitate the positioning of several motor shaft supports 29 within the length of a single pipe segment 6’. The length of the pipe segment 6’ is defined as the length between a first and a second end of the pipe segment 6’. The second end of the pipe segment 6’ is opposite to the first end of the pipe segment 6’ in the longitudinal direction of the first elongated pipe 6.

[0069] In a preferred embodiment the spacers are seated between two seating rings each mounted in flanges 26 connecting pipe segments 6’ and each spacer comprises seating for several shaft supports 29. In this preferred embodiment the spacers are made of two rails which define spacer units 3 and collectively contribute to define the spacer 2. The rails are made from metal, either by metal extrusion or sheet metal processing. In this preferred embodiment the first elongated pipe 6 extends inside a second elongated pipe 12 and fluid is pumped in both pipes.

[0070] In another preferred embodiment the spacers are seated between two seating rings each mounted in flanges 26 connecting pipe segments 6’ and each spacer comprises seating for several shaft supports 29. In this preferred embodiment the spacers are made of two rails which define spacer units 3 and collectively contribute to define the spacer 2. The rails are made from metal, either by metal extrusion or sheet metal processing. In this preferred embodiment the first elongated pipe 6 extends inside a second elongated pipe 12 and fluid is only transported in the second elongated pipe. Lubricant may be circulated in the first elongated pipe 6.

[0071] In another preferred embodiment the spacers are seated between two seating rings each mounted in flanges 26 connecting pipe segments 6’ and each spacer comprises seating for several shaft supports 29. In this preferred embodiment the spacers are made of two rails which define spacer units 3 and collectively contribute to define the spacer 2. The rails are made from metal, either by metal extrusion or sheet metal processing. In this preferred embodiment the first elongated pipe 6 extends in parallel to a second elongated pipe 12 and fluid is pumped in the second elongated pipe 12. Lubricant may be circulated in the first elongated pipe 6.

[0072] In another preferred embodiment the spacers are bolted to seatings each mounted in flanges 26 connecting pipe segments 6’ and each spacer comprises seating for several shaft supports 29. In this preferred embodiment the spacers are made of two rails which define spacer units 3 and collectively contribute to define the spacer 2. The rails are made from metal, either by metal extrusion or sheet metal processing. In this preferred embodiment the first elongated pipe 6 extends inside a second elongated pipe 12 and fluid is pumped in both pipes.

[0073] In another preferred embodiment the spacers are welded to seatings each mounted in flanges 26 connecting pipe segments 6’ and each spacer comprises seating for several shaft supports 29. In this preferred embodiment the spacers are made of two rails which define spacer units 3 and collectively contribute to define the spacer 2. The rails are made from metal, either by metal extrusion or sheet metal processing. In this preferred embodiment the first elongated pipe 6 extends inside a second elongated pipe 12 and fluid is pumped in both pipes.

[0074] The following is an itemized list of embodiments A and B, according to the invention:

[0075] Item A1 ) A fluid flow system (1 ) including a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, comprising

[0076] - a first elongated pipe (6) having a first end (5) and a second end (7), wherein the first elongated pipe (6) is comprised of a plurality of elongated pipe segments (6’) each having a first end and a second end opposite to the first end of the pipe segment (6’),

[0077] - a motor (9) at the first end (5) of the first elongated pipe,

[0078] - a pump impeller (10) at the second end (7) of the first elongated Pipe,

[0079] - a motor shaft (8) extending inside the first elongated pipe (6) from the motor (9) to the impeller (10), for rotating the pump impeller,

[0080] - a plurality of spaced apart motor shaft supports (29) having a portion defining a bearing (4) for providing sideways support for the motor shaft (8), wherein each pipe segment (6’) comprises one spacer (2) having a plurality of motor shaft supports (29), such as 2-20 motor shaft supports, arranged apart from one another in the longitudinal direction of the first elongated pipe (6).

[0081] Item A2) A fluid flow system (1 ) including a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, comprising

[0082] - a first elongated pipe (6) having a first end (5) and a second end (7), wherein the first elongated pipe (6) is comprised of a plurality of elongated pipe segments (6’) each having a first end and a second end opposite to the first end of the pipe segment (6’), - a motor (9) at the first end (5 of the first elongated pipe (6)),

[0083] - a pump impeller (10) at the second end (7) of the first elongated pipe (6)

[0084] - a motor shaft (8) extending inside the first elongated pipe (6) from the motor (9) to the impeller (10), for rotating the pump impeller,

[0085] - a plurality of spaced apart motor shaft supports (29) having a portion defining a bearing (4) for providing sideways support for the motor shaft (8), wherein each pipe segment (6’) comprises several spacers (2) each having at least one motor shaft support (29) arranged apart from one another in the longitudinal direction of the first elongated pipe (6).

[0086] Item A3) The fluid flow system according to any preceding item A, wherein each spacer (2) is located between two seating rings or bearing assemblies, such as seating rings mounted in flanges (26) connecting pipe segments (6’), configured to prevent the spacers (2) from moving past the seating rings in the longitudinal direction of the first elongated pipe (6) thereby confining each spacer (2).

[0087] Item A4) The fluid flow system (1 ) according to any preceding item A, wherein at least one of the spacers (2) are comprised from two spacer units (3) with each spacer unit (3) being defined by a rail extending in the longitudinal direction of the first elongated pipe (6).

[0088] Item A5) The fluid flow system according to any preceding item A, wherein at least one spacer (2) is comprised of a plurality of spacer units (3), held together by at least one shaft support (29) and / or bearing (4).

[0089] Item A6) The fluid flow system (1 ) according to item A1 , wherein the first elongated pipe (6) extends inside a second elongated pipe (12) configured for transporting the fluid, with or without a portion of the fluid being transported inside the first elongated pipe (6).

[0090] Item A7) The fluid flow system (1 ) according to item A1 , wherein a second elongated pipe (12) is connected to the impeller housing (14) and is used for transporting the fluid, with the second elongated pipe (12) alongside, and optionally at an angle to, the first elongated pipe (6).

[0091] Item A8) The fluid flow system (1 ) according to any of the previous item A, said spacers (2) being stacked upon each other in said first elongated pipe (6) and each supporting a plurality of said shaft supports.

[0092] Item A9) The fluid flow system (1 ) according to any of the preceding item A, wherein the spacers (2) each define tubular structures preferably forming a lining of the first elongated pipe (6).

[0093] Item A10) The fluid flow system (1 ) according to any of the preceding item A, wherein said spacers (2) including a plurality of said shaft supports (29) are secured to the first elongated pipe (6), such as to the inside of the first elongated pipe (6), by bolts, pins, screws, welding, spot welding, adhesives, finger joint connections, press-fitting, and / or threads.

[0094] Item A11 ) The fluid flow system (1 ) according to any preceding item A, wherein the spacer (2) and shaft support (29) form an integral unit.

[0095] Item A12) The fluid flow system (1 ) according to any preceding item A, wherein the spacer (2), shaft support (29) and bearing (4) form an integral unit.

[0096] Item A13) The fluid flow system according to any preceding item A, wherein the spacers (2) and shaft support (29) allow for the circulation of a lubricant for the bearings (2). Item A14) The fluid flow system (1 ) according to any of the preceding item A, wherein at least some of the spacers (2) are assembled from a plurality of spacer units (3) which collectively support one or several bearings (4).

[0097] Item A15) The fluid flow system (1 ) according to any of the preceding item A, wherein the spacers (2) are configured with seatings and / or securing means (24) for one or several bearings (4), such as at the end of the spacer (2), such as on the inside of the spacer (2), such as threaded section on the inside of the spacer (2).

[0098] Item A16) The fluid flow system (1 ) according to any of the preceding item A, wherein the spacers (2) have a length (I) of 200-2000 mm, such as 250-300 mm, such as 350-450 mm, such as 700-800 mm, such as 1000-1500 mm.

[0099] Item A17) The fluid flow system (1 ) according to any of the preceding item A, wherein the spacers (2) have an outer diameter (0) of 5-500 mm, such as 5- 150mm.

[0100] Item A18) The fluid flow system according to any of item A1 , A2, A3 or A9, wherein the spacer (2) is comprised of one or several continuous structures, such as at least one threaded bar, allowing for the shaft supports (29) to be secured at an arbitrary point along the spacer (2).

[0101] Item A19) A method of assembling the fluid flow system (1 ) according to any of the previous item A, wherein the spacers (2), preferably with associated shaft supports (29), are inserted into the first pipe (6), or into segments (6’) thereof, either one by one or as assemblies. Item A20) The assembling method according to item A19, comprising the steps of mounting a pipe segment (6’) of the first elongated pipe (6), inserting a seating ring or bearing assembly into a flange (26) of the pipe segment (6’), connecting a new pipe segment (6’) to the previous pipe segment (6’), inserting a spacer (2) having a plurality of motor shaft supports (29), and repeating this method until the desired length of the first elongated pipe (6) is reached.

[0102] Item A21 ) The assembling method of item A19 or A20, wherein the spacers (2) are secured and / or confined in the longitudinal direction of the first pipe at the first (5) and / or second end (7) of the first elongated pipe (6).

[0103] Item B1 ) A fluid flow system (1 ) including a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, comprising

[0104] - a first elongated pipe (6) having a first (5) and a second end (7)

[0105] - a motor (9) at the first end (5)

[0106] - a pump impeller (10) at the second end (7)

[0107] - a motor shaft (8) extending inside the first elongated pipe (6) from the motor (9) to the impeller (10), for rotating the pump impeller,

[0108] - a plurality of spaced apart motor shaft supports (29) with a bearing (4) supporting the motor shaft (8) along its length, characterized in the flow system (1 ) comprising one or several spacers (2) arranged between the first elongated pipe (6) and the motor shaft (8), each supporting at least one motor shaft support (29) with a portion defining a bearing (4).

[0109] Item B2) The fluid flow system (1 ) according to item B1 , wherein the first elongated pipe (6) extends inside a second elongated pipe (12) configured for transporting the fluid, with or without a portion of the fluid being transported inside the first elongated pipe (6). Item B3) The fluid flow system (1 ) according to item B1 , wherein a second elongated pipe (12) is connected to the impeller housing (14) and is used for transporting the fluid, with the second elongated pipe (12) alongside, or at an angle to, the first elongated pipe (6).

[0110] Item B4) The fluid flow system (1 ) according to any of the previous item B, including a plurality of spacers (2) wherein the spacers (2) are stacked upon each other.

[0111] Item B5) The fluid flow system (1 ) according to any of the preceding item B, wherein the spacers (2) each define tubular structures preferably forming a lining of the first elongated pipe (6).

[0112] Item B6) The fluid flow system (1 ) according to any of the preceding item B, wherein the spacers (2) are secured to the first elongated pipe (6), such as by bolts, pins, screws, welding, spot welding, adhesives, finger joint connections, press-fitting, and / or threads.

[0113] Item B7) The fluid flow system (1 ) according to any preceding item B wherein the spacer (2) and shaft support (29) form an integral unit.

[0114] Item B8) The fluid flow system (1 ) according to any preceding item B wherein the spacer (2), shaft support (29) and bearing (4) form an integral unit.

[0115] Item B9) The fluid flow system according to any preceding item B in which the spacers (2) and shaft support (29) allow for the circulation of a lubricant for the bearings (2). Item B10) The fluid flow system (1 ) according to any of the preceding item B, wherein at least some of the spacers (2) are assembled from a plurality of spacer units (3) which collectively support one or several bearings (4).

[0116] Item B11 ) The fluid flow system (1 ) according to any of the preceding item B, wherein the spacers (2) are configured with seatings (24) for one or several bearings (4), such as at the end of the spacer (2), such as on the inside of the spacer (2), such as threaded section on the inside of the spacer (2).

[0117] Item B12) The fluid flow system (1 ) according to any of the preceding item B, wherein the spacers (2) have a length (I) of 200-2000 mm, such as 250-300 mm, such as 350-450 mm, such as 700-800 mm, such as 1000-1500 mm.

[0118] Item B13) The fluid flow system (1 ) according to any of the preceding item B, wherein the spacers (2) have an outer diameter (0) of 5-150 mm.

[0119] Item B14) The fluid flow system according to any of item Bs 1 , 2, 3 and 9, wherein the spacer (2) is comprised of continuous structures, such as at least one threaded bar, allowing for the shaft supports (29) to be secured at an arbitrary point along the spacer (2).

[0120] Item B15) A method of assembling the fluid flow system (1 ) according to any of the previous item Bs, wherein the spacers (2), preferably with associated shaft supports (29), are inserted into the first pipe (6), or into segments (6’) thereof, either one by one or as assemblies so as to be stacked on top of each other.

[0121] Item B16) The assembling method of item B15 wherein the spacers (2) are secured in the vertical direction at the first (5) and / or second end (7) of the first elongated pipe (6). References

[0122] 1 fluid flow system

[0123] 2 spacer

[0124] 3 spacer unit

[0125] 4 bearing

[0126] 5 first end of first elongated pipe

[0127] 6 first elongated pipe

[0128] 6’ segment of first elongated pipe

[0129] 7 second end of first elongated pipe

[0130] 8 motor shaft

[0131] 9 motor

[0132] 10 impeller

[0133] 12 second elongated pipe

[0134] 14 Impeller housing

[0135] 16 tank

[0136] 18 cargo cavity

[0137] 20 sealing component

[0138] 22 securing means for shaft support

[0139] 24 shaft support seat

[0140] 26 flange of first elongated pipe

[0141] 28 securing means on shaft support

[0142] 29 shaft support

[0143] 30 flange of second elongated pipe

[0144] 31 arm

[0145] 50 first end of spacer

[0146] 52 second end of spacer

Claims

26Claims1 . A fluid flow system (1 ) including a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, comprising- a first elongated pipe (6) having a first end (5) and a second end (7), wherein the first elongated pipe (6) is comprised of a plurality of elongated pipe segments (6’) each having a first end and a second end opposite to the first end of the pipe segment (6’),- a motor (9) at the first end (5) of the first elongated pipe (6),- a pump impeller (10) at the second end (7) of the first elongated pipe (6),- a motor shaft (8) extending inside the first elongated pipe (6) from the motor (9) to the impeller (10), for rotating the pump impeller (10),- a plurality of spaced apart motor shaft supports (29) having a portion defining a bearing (4) for providing sideways support for the motor shaft (8), wherein each pipe segment (6’) comprises one spacer (2) having a plurality of motor shaft supports (29), such as 2-20 motor shaft supports (29), arranged apart from one another in the longitudinal direction of the first elongated pipe (6).

2. A fluid flow system (1 ) including a pump, such as for pumping of liquefied gasses from the cargo hold of a ship, comprising- a first elongated pipe (6) having a first end (5) and a second end (7), wherein the first elongated pipe (6) is comprised of a plurality of elongated pipe segments (6’) each having a first end and a second end opposite to the first end of the pipe segment (6’),- a motor (9) at the first end (5 of the first elongated pipe (6)),- a pump impeller (10) at the second end (7) of the first elongated pipe (6)- a motor shaft (8) extending inside the first elongated pipe (6) from the motor (9) to the impeller (10), for rotating the pump impeller (10),- a plurality of spaced apart motor shaft supports (29) having a portion defining a bearing (4) for providing sideways support for the motor shaft (8), wherein each pipe segment (6’) comprises several spacers (2) each having at least one motor shaft support (29) arranged apart from one another in the longitudinal direction of the first elongated pipe (6).

3. The fluid flow system according to any preceding claim, wherein each spacer (2) is located between two seating rings or bearing assemblies, such as seating rings mounted in flanges (26) connecting pipe segments (6’), configured to prevent the spacers (2) from moving past the seating rings in the longitudinal direction of the first elongated pipe (6) thereby confining each spacer (2).

4. The fluid flow system (1 ) according to any preceding claim, wherein at least one of the spacers (2) are comprised from two spacer units (3) with each spacer unit (3) being defined by a rail extending in the longitudinal direction of the first elongated pipe (6).

5. The fluid flow system according to any preceding claim, wherein at least one spacer (2) is comprised of a plurality of spacer units (3), held together by one or more of at least one shaft support (29) and at least one bearing (4).

6. The fluid flow system (1 ) according to claim 1 , wherein the first elongated pipe (6) extends inside a second elongated pipe (12) configured for transporting the fluid, with or without a portion of the fluid being transported inside the first elongated pipe (6).

7. The fluid flow system (1 ) according to claim 1 , wherein a second elongated pipe (12) is connected to the impeller housing (14) and is used for transporting the fluid, with the second elongated pipe (12) alongside, and optionally at an angle to, the first elongated pipe (6).

8. The fluid flow system (1 ) according to any of the previous claim, said spacers (2) being stacked upon each other in said first elongated pipe (6) and each supporting a plurality of said shaft supports.

9. The fluid flow system (1 ) according to any of the preceding claims, wherein the spacers (2) each define tubular structures preferably forming a lining of the first elongated pipe (6).

10. The fluid flow system (1 ) according to any of the preceding claims, wherein said spacers (2) including a plurality of said shaft supports (29) are secured to the first elongated pipe (6), such as to the inside of the first elongated pipe (6), by one or more of bolts, pins, screws, welding, spot welding, adhesives, finger joint connections, press-fitting, and threads.11 . The fluid flow system (1 ) according to any preceding claim, wherein the spacer (2) and shaft support (29) form an integral unit.

12. The fluid flow system (1 ) according to any preceding claim, wherein the spacer (2), shaft support (29) and bearing (4) form an integral unit.

13. The fluid flow system according to any preceding claim, wherein the spacers (2) and shaft support (29) allow for the circulation of a lubricant for the bearings (2).2914. The fluid flow system (1 ) according to any of the preceding claims, wherein at least some of the spacers (2) are assembled from a plurality of spacer units (3) which collectively support one or several bearings (4).

15. The fluid flow system (1 ) according to any of the preceding claims, wherein the spacers (2) are configured with one or more of seatings and securing means (24) for one or several bearings (4), such as at the end of the spacer (2), such as on the inside of the spacer (2), such as threaded section on the inside of the spacer (2).

16. The fluid flow system (1 ) according to any of the preceding claims, wherein the spacers (2) have a length (I) of 200-2000 mm, such as 250- 300 mm, such as 350-450 mm, such as 700-800 mm, such as 1000- 1500 mm.

17. The fluid flow system (1 ) according to any of the preceding claims, wherein the spacers (2) have an outer diameter (0) of 5-500 mm, such as 5-150mm.

18. The fluid flow system according to any of claims 1 , 2, 3 or 9, wherein the spacer (2) is comprised of one or several continuous structures, such as at least one threaded bar, allowing for the shaft supports (29) to be secured at an arbitrary point along the spacer (2).

19. A method of assembling the fluid flow system (1 ) according to any of the previous claims, wherein the spacers (2), preferably with associated shaft supports (29), are inserted into the first pipe (6), or into segments (6’) thereof, either one by one or as assemblies.3020. The assembling method according to claim 19, comprising the steps of mounting a pipe segment (6’) of the first elongated pipe (6), inserting a seating ring or bearing assembly into a flange (26) of the pipe segment (6’), connecting a new pipe segment (6’) to the previous pipe segment (6’), inserting a spacer (2) having a plurality of motor shaft supports (29), and repeating this method until the desired length of the first elongated pipe (6) is reached.21 . The assembling method of claim 19 or 20, wherein the spacers (2) are secured and / or confined in the longitudinal direction of the first pipe at one or more of the first (5) and second end (7) of the first elongated Pipe (6).

22. A method of pumping a fluid, preferably liquefied gas, from a fluid container of a vessel, such as the cargo hold of a ship, the method comprising:-providing the system according to any of claims 1-18 of the invention; and-activating the system so as to initiate the pumping.

23. Use of the system according to any of claims 1 - 18, for pumping of a fluid, preferably liquefied gas, from a fluid container of a vessel, such as the cargo hold of a ship.

Images