Improved high-performance pump

Abstract

A high-performance pump (1, 1') for a first cryogenic fluid is described, comprising a casing (2) which develops along a flow direction of the first cryogenic fluid, at least one impeller (5) and a shaft (A) connected and adapted to actuate the at least one impeller (5). The casing (2) comprises a first portion (3) and a second portion (4), the second portion (4) being adapted to contain the shaft (A) and which the at least one impeller (5) protrudes from, the first portion (3) being in extension of the second portion (4) at the at least one impeller (5). At least the first portion (3) of the casing (2) comprises a main through- duct (9) comprised between an inlet (8) of the pump (1, 1') and the at least one impeller (5), the main duct (9) being adapted to bring the first cryogenic fluid from the inlet (8) to the at least one impeller (5). An external wall (10) defines the main duct (9), this external wall (10) comprising a layered structure and at least one first hollow layer (11). The at least one first hollow layer (11) is provided along the longitudinal development of the first portion (3) of the casing (2) in the flow direction of the first cryogenic fluid. A related system is also provided, comprising said pump and at least one connected electric motor, and, possibly, a turbine or any component, sub-system or system adapted to supply the mechanical energy to a shaft of the pump. (Fig. 1)

Description

[0001] Title: Improved high-performance pump

[0002] DESCRIPTION

[0003] Field of application

[0004] The present invention relates to an improved high-performance pump for maintaining the optimal operating conditions, in particular in the case in which the working flow is represented by a cryogenic fluid.

[0005] The “cryogenic fluids” referred to in the present document are the refrigerated liquefied gases (for example, but not only, oxygen, nitrogen, argon) or the liquid phase of liquefied gases. In general, both the so-called “refrigerated” fluids such as ammonia for example, and the true “cryogenic” fluids with a very low operating temperature are taken into consideration.

[0006] This invention finds an application in particular in the space field, where cryogenic fluids are often used.

[0007] The following description is made with reference to this field of application with the only purpose of simplifying the exposition thereof.

[0008] Prior art

[0009] As it is well known, in the field of liquid-propellant rocket propulsion pumps play a key role.

[0010] Electric pumps or turbopumps will be indifferently indicated below with the term pumps.

[0011] They have the task of pumping propellants from the tanks thereof up to the high-pressure combustion chamber of rocket motors.

[0012] In these high-performance pumps, both in current propulsion and energy systems and in those currently in development, refrigerated and / or cryogenic fluids or propellants, such as liquid oxygen, liquid methane, liquid hydrogen, are frequently used.

[0013] In the following description, the refrigerated liquefied gases (for example, but not only, oxygen, nitrogen, argon) or the liquid phase of liquefied gases will be extensively indicated with “cryogenic fluids”. In general, both the so-called “refrigerated” fluids such as ammonia for example, and the true “cryogenic” fluids with a very low operating temperature are taken into consideration.

[0014] The use of pumps also allows to reduce the storage pressure of the cryogenic fluids and accordingly the total mass of the tanks thereof as well.

[0015] As mentioned, a primary function of the pump is to transport a volumetric flow rate of fluid increasing the pressure thereof to a specified pressure level. The required work is transferred from the shaft to the fluid through rotating parts (for example an axial bladed stage, or an impeller, or a combination of axial stage and centrifugal impeller, or a multistage combination based on the two previous ones; in general at least one impeller) which increase the total pressure.

[0016] Then a bladed or non-bladed diffuser and a volute collect and decelerate the fluid by converting the kinetic energy thereof into static pressure.

[0017] The fluid pressure is thereby increased between the inlet section and the discharge section of the pump.

[0018] The fluid “domain” is contained between the rotating parts, comprising for example shaft, bladed axial stage, impeller, bearings and sealing elements, and the stationary parts, such as for example the suction housing, or casing, the rear housing, or casing, other bearings and sealing elements which define the primary and secondary flow paths.

[0019] When adopting cryogenic fluids, the transport, handling and storage thereof are very important. The cooling process, or “quenching”, is the initial step of the cryogenic fluid transport which provides a heat transfer process with liquid-vapor phase change characterized by a so-called “boiling curve”.

[0020] The pump then undergoes a so-called “chilldown” process, i.e. a step of removing the thermal energy stored in the walls of the pump which must contact the cryogenic fluid, to prevent this thermal energy from being absorbed by the liquid cryogen used in propulsion and energy systems.

[0021] This “chilldown” step is very important in systems which operate with cryogenic fluids, in particular liquid hydrogen.

[0022] During the pump operation one of the most frequent problems is represented by cavitation phenomena.

[0023] Cavitation is a phenomenon which occurs when the local absolute static pressure of a fluid drops below the fluid vapor pressure and, as a result, vapor bubbles appear. When the bubbles are conveyed downstream, they reach a point in which the pressure increases again above the vapor pressure, they collapse and create a sudden and very high pressure pulse.

[0024] Cavitation is generally a detrimental process which can involve damages to the surfaces of the materials close to the area in which the bubbles collapse, a considerable degradation of the pump performances, a negative influence both on the steady-state fluid flow and on the non- stationary or dynamic flow response and vibrations.

[0025] Since the fluid vapor pressure depends on temperature, the thermal management becomes crucial to avoid, or at least limit, cavitation as well.

[0026] Particularly in cryogenic cavitation flows, where the liquid-vapor density ratio is low and the operating point is close to the boiling point, the thermal effects play an important role in altering the dynamics of the cavitation bubbles or cavitating flow. The currently used solutions, although effective and widely used, are still not perfectly efficient in terms of temperature and pressure management to prevent problems of this type from occurring.

[0027] The technical problem of the present invention is thus to devise a technical solution which solves the current drawbacks existing in the prior art.

[0028] Object of the invention is also to provide a solution which allows to reduce the number of components adapted to control the above parameters.

[0029] A further object of the invention is to provide a solution which can be implemented through an efficient technology.

[0030] Finally, object of the invention is to provide a solution which can be both more effective but at the same time also more economic compared to current prior art solutions.

[0031] Summary of the invention

[0032] The solution idea underlying the present invention is to provide a solution which allows to insulate in terms of temperature the cryogenic working fluid passing in a high-performance pump, substantially mitigating the influences of the external environment through the walls of the pump itself.

[0033] Based on this solution idea the technical problem is solved by a high- performance pump for a first cryogenic fluid comprising a casing which develops along a flow direction of the first cryogenic fluid, at least one impeller and a shaft connected and adapted to actuate this at least one impeller.

[0034] The casing comprises a first portion and a second portion, the latter being adapted to contain the shaft and which the at least one impeller protrudes from, whereas the first portion is in extension of the second portion at the at least one impeller. At least the first portion of the casing comprises a main through-duct comprised between an inlet of the pump and the at least one impeller, the main duct being adapted to bring the first cryogenic fluid from the inlet to the at least one impeller, and an external wall defining this main duct.

[0035] The external wall comprises a layered structure and at least one first hollow layer, this at least one first hollow layer being provided along the longitudinal development of the first portion of the casing in the flow direction of the first cryogenic fluid.

[0036] The at least one impeller could consist of several parts: one or more inducers and / or impellers. In the case of hydrogen as a cryogenic fluid, a multi-stage machine is generally required.

[0037] Advantageously, the present solution allows the main duct through which the working fluid passes in cryogenic conditions to be insulated from the external influence which could cause the temperature thereof to vary and compromise the operation also due to the occurrence of cavitation problems.

[0038] In an embodiment, at least one connection branch downstream of the at least one impeller is provided, this branch being adapted to convey a first fraction of the first cryogenic fluid into the first hollow layer.

[0039] Advantageously, the present solution allows the hollow layer to be filled with a small quantity of the same cryogenic fluid, so that possible external influences which would lead to the increase in the internal temperature are absorbed by this small quantity of cryogenic fluid which changes phase, without affecting the temperature of the working fluid in cryogenic conditions in the main duct.

[0040] Nothing prevents to provide a branch and a related bleed carried out in a different position, with a possible different fluid flowing direction.

[0041] In fact, in an alternative embodiment, at least one connection branch upstream of the at least one impeller is provided, this branch being adapted to convey a first fraction of the first cryogenic fluid into the first hollow layer.

[0042] Advantageously, the present solution is productively simplified, a path of the first hollow layer encompassing the wall of a volute of the casing not being provided.

[0043] Alternatively, the first hollow layer provides an alternative inlet to supply a second cryogenic fluid, which is different from the first cryogenic fluid, to the first hollow layer.

[0044] Advantageously, the present solution allows to select a possible different second cryogenic fluid to be intended for the insulation of the main duct, this second cryogenic fluid being selected depending on different operating, structural or contingent cost requirements.

[0045] Still alternatively, the external wall is made with the first hollow layer under vacuum conditions.

[0046] Advantageously, the present solution does not require to provide accesses to the hollow layer, but is in any case efficient given the optimal thermal insulation ensured by an intermediate layer under vacuum conditions.

[0047] Still alternatively, the first hollow layer is filled with insulating material.

[0048] Advantageously, the present solution can be optimized with respect to specific application requirements, by varying the adopted insulating material.

[0049] According to a further embodiment, the external wall comprises a second hollow layer, which is preferably parallel to the first hollow layer.

[0050] Advantageously, the present solution allows to insulate the main duct even more efficiently but also to select different combinations of insulating materials depending on the different needs. In a preferred embodiment, the external wall is made with the second hollow layer filled with thermally insulating material.

[0051] The thermally insulating material can be selected for example, but not limitedly, from bubble glass, PTFE, which has also a structural function, perlite powder, aerogel, etc.

[0052] Advantageously, this second layer, generally placed further outside the external wall with respect to the first layer, removes, for example, a vaporization condition of cryogenic fluid which can flow in this first layer.

[0053] Alternatively, a second purge branch adapted to convey a second fraction of first cryogenic fluid into the second hollow layer is provided.

[0054] Advantageously, the present solution, always adopting the recovery of part of the first cryogenic fluid constitutes a double barrier for the main duct, with a possible double vaporization of cryogenic fluid in the two hollow layers.

[0055] Alternatively, a second inlet for the second hollow layer is provided, this second inlet being adapted to allow the introduction of a second cryogenic fluid, which is different from the first cryogenic fluid.

[0056] Advantageously, the present solution allows to select and match different cryogenic fluids depending on the operating needs.

[0057] Still alternatively, the external wall is made with said second hollow layer under vacuum conditions.

[0058] Advantageously, vacuum constitutes an optimal thermal insulation shield for the main duct.

[0059] Obviously, nothing prevents to combine, depending on the requirements, the various embodiments described which do not put any constraint in this regard, or with other obvious alternatives thereof.

[0060] According to a further embodiment, the external wall comprises an insulating layer which is adjacent to the first hollow layer or to the second hollow layer and opposite to the main duct.

[0061] Advantageously, the present solution further insulates in an optimal manner said main duct in which the working fluid flows in cryogenic conditions and this solution can be independently applied both in the case in which a second hollow layer is also present and in the case in which only the first hollow layer is present.

[0062] In fact, nothing prevents to provide different combinations of the layers of the above-described external wall.

[0063] According to an embodiment of the invention, the at least one first hollow layer is made with a solution of continuity in the first portion and in the second portion of the casing.

[0064] Advantageously, the present solution allows to insulate the working fluid in cryogenic conditions along the entire development of the pump.

[0065] Alternatively, nothing prevents to provide a different solution in the second portion of the casing, as well as nothing prevents to combine different embodiments according to the present invention between the two portions of the casing.

[0066] According to a further aspect of the invention, a system comprising a pump according to the above description is provided, and at least one electric motor comprising an external case comprising an external wall with a layered structure which is similar to that of the pump.

[0067] Advantageously, it is possible to extend and associate the insulation properties of the present invention even to the external case of the at least one electric motor connected to the pump.

[0068] Preferably, the system further comprises at least one turbine, or any component, sub-system or system adapted to supply mechanical energy to at least one shaft of said one or more pumps. The features and advantages of the pump according to the invention will be apparent from the following description of exemplary embodiments given by way of non-limiting examples with reference to the attached drawings.

[0069] Brief description of the drawings

[0070] In the drawings:

[0071] Figure 1 schematically shows a high-performance pump according to the present invention;

[0072] Figure 2 shows a cross-sectional view of the pump of Figure 1;

[0073] Figure 3 shows a cross-sectional view of an alternative of the pump of Figure 1 ;

[0074] Figure 4 shows a first embodiment of an external wall of a first portion of the casing of the pump of Figure 1 with an exemplary and nonlimiting direction of a flow in a hollow layer;

[0075] Figure 5 shows a second embodiment of an external wall of a first portion of the casing of the pump of Figure 1 ;

[0076] Figure 6 shows a third embodiment of an external wall of a first portion of the casing of the pump of Figure 1 ;

[0077] Figure 7 shows a fourth embodiment of an external wall of a first portion of the casing of the pump of Figure 1 ;

[0078] Figure 8 shows a fifth embodiment of an external wall of a first portion of the casing of the pump of Figure 1 ;

[0079] Figure 9 shows a schematic view of a pump according to the invention connected to an electric motor.

[0080] Detailed description With reference to the figures, in particular to Figures 2 and 3, a pump manufactured according to the present invention is described, globally indicated with 1, 1’.

[0081] It should be noted that the figures are schematic views and are not drawn to scale, but are instead drawn so as to emphasize the important features of the invention. Furthermore, in the figures, the different pieces are schematically represented, the shape thereof may vary depending on the desired application. Moreover, particular devices illustrated in a figure in relation to an embodiment can also be used in one or more embodiments illustrated in the other figures.

[0082] Furthermore, elements which are structurally and functionally identical in the different figures, and in particular similar to the above-described prior art solutions, are indicated below with the same alphanumeric references.

[0083] In the following description, relative terms such as “above”, “below”, “upwards”, “downwards” will be used, referring to the figures only to simplify the exposition thereof.

[0084] Finally, indications of particular geometries (circular, rectangular) or of the arrangement of the elements (parallel, orthogonal, contiguous) as well as the term “substantially” are always to be understood in relation to physical and not geometrically abstract elements, and thus the tolerances introduced by the transition from a pure mathematical / geometrical world to the real world must always be taken into consideration.

[0085] The pump 1, in the exemplary embodiment of Figure 2, comprises a casing 2 comprising a first portion 3 and a second portion 4 removably coupled to each other by coupling means, such as for example bolts, on a transverse coupling surface, being it transverse or not, to the flow direction F of a working fluid passing through the pump 1.

[0086] Advantageously, this simplifies a disassembly of the pump, which is a useful feature especially during maintenance.

[0087] Obviously, nothing prevents to provide an embodiment in which the first portion 3 and the second portion 4 are made as a single piece, without the need for any subsequent mutual coupling, depending on the contingent manufacturing and operating needs for each application.

[0088] In the present embodiment an electric pump is mainly described, but nothing prevents, as mentioned, to apply the same solution in a turbopump.

[0089] The working fluid is represented by a cryogenic fluid, for example liquid hydrogen, which maintains this state thereof at a temperature of about 20 K.

[0090] The second portion 4 of the casing 2 is adapted to contain a shaft A to which at least one impeller 5 which protrudes from this second portion 4 is connected.

[0091] The at least one impeller 5 could consist of several parts: one or more inducers and / or impellers. In the case of hydrogen as a cryogenic fluid a multi-stage machine is generally required.

[0092] The shaft A is combined with related suitable support elements 6 with related sealing elements 7.

[0093] The first portion 3, in the present exemplary and non-limiting embodiment, is coupled to the second portion 4 at said at least one impeller 5.

[0094] The working fluid is introduced through at least one inlet 8 into a main through-duct 9 of the first portion 3 of the casing 2, which brings said working fluid at the at least one impeller 5.

[0095] According to the present invention, the main duct 9 is defined by an external wall 10 with a layered structure. Specifically, according to the embodiment which is visible in the sectional view of Figure 2, the external wall 10 comprises therein a first hollow layer 11 which develops in the first portion 3 of the casing 2 longitudinally, and preferably but non limitedly, in a parallel manner with respect to the flow F of the cryogenic fluid along the pump 1.

[0096] The first hollow layer 11 can consist of a single layer or of different longitudinal cavities, which are axisymmetric or asymmetric, in the geometry of the casing 2.

[0097] This first hollow layer 11 is adapted to create a discontinuity in the external wall 10 to insulate the working fluid in cryogenic conditions which flows in the main duct 9 with respect to the outside of the first portion 3 of the casing 2, so as to thermally insulate the main duct 9 and avoid temperature variations which would involve problems both clearly for maintaining the cryogenic fluid in ideal temperature conditions, and for the related pressure variations with the implications explained above in terms of cavitation.

[0098] In other words, the present solution allows to limit the heat conduction from the external environment, maintain the working fluid within a minimum temperature range specified by the application requirements and maintain the structural integrity of the pump 1 during the entire life cycle.

[0099] Even more specifically, according to the embodiment as always visible in the sectional view in Figure 2, downstream of the at least one impeller 5 a branch 12 of the flow which flows through the pump 1 is provided, which conveys a first fraction of the cryogenic fluid into the first hollow layer 11.

[0100] Nothing prevents to provide a branch and a related bleed carried out in a different position.

[0101] In fact, in an alternative embodiment, represented in Figure 3, a pump 1’ is provided, comprising at least one connection branch 12’ upstream of the at least one impeller 5, this branch 12’ being always adapted to convey a first fraction of the first cryogenic fluid into the first hollow layer 11.

[0102] Advantageously, the present solution is productively simplified, a path of the first hollow layer 11 encompassing the wall of a volute of the casing not being provided.

[0103] Figure 4 represents a generic flowing direction of the cryogenic fluid, but it is also possible to have different configurations with a different fluid flowing direction with respect to what is depicted in Figure 4.

[0104] With the above-envisaged solutions, therefore, the first hollow layer 11 is filled with cryogenic fluid, which flows in the present embodiment, as can be seen, in parallel, or however along the direction of the flow which flows inside the first hollow layer 11 , with respect to the cryogenic fluid in the main duct 9. Nothing prevents to provide a different development direction of the first hollow layer 11.

[0105] This small quantity of fluid flows at the same temperature as the fluid operating in the pump 1.

[0106] Any heat flow coming from the external environment through the pump 1 , 1 ’ is thereby mitigated by the change of state of this small quantity of fluid without affecting the operating conditions of the fluid in the flow path in the main duct 9. This allows, as mentioned, to avoid any increase in temperature in the cryogenic fluid which flown in the main duct 9 and to have a temperature gradient, or temperature difference, which is zero or substantially zero.

[0107] In fact, it is recalled that, considering the surface of the main duct 9 lapped by the moving cryogenic fluid, if a difference exists between the temperature of the surface of the wall TO and that of the fluid Tl, i.e. if it is TO>T1, a heat flow is established between the wall and the fluid according to the model: Q=hAAT where h is a coefficient of proportionality which is called convective conductance and which depends on the fluid physical properties, on the flow dynamics and on the wall geometry. This type of heat transport is defined as thermal convection, or to be more precise, average conductance given the variability of the parameter h.

[0108] Preferably, the material of the external wall 10 interposed between the main duct 9 and the first hollow layer 11 is selected so as to maintain the temperature gradient, or temperature difference, at zero or substantially zero.

[0109] This further limits the possibility to increase the temperature of the fluid in the main duct 9, and thus any change of state which could lead to the creation of vapor bubbles and start cavitation.

[0110] According to an alternative not shown, the first hollow layer 11 provides an alternative inlet, to supply a second cryogenic fluid, which is different from the working one, i.e. the first cryogenic fluid, to the first hollow layer 11.

[0111] In other words, in this case, the same cryogenic fluid which is flowing inside the main duct 9 of the pump 1, 1’ is not adopted, but a second cryogenic fluid is introduced through an alternative inlet, not connected to the main flow.

[0112] This solution may be preferred in the case in which it is desired to adopt a second cryogenic fluid which is different from the first cryogenic fluid, or in case of different contingent manufacturing requirements with specific simplifications.

[0113] Still furthermore, according to a further alternative not shown, the external wall 10 is made so as to have a vacuum condition in the first hollow layer 11.

[0114] This embodiment allows to have a good thermal insulation, although it is lower than what is proposed in the previous alternatives, of the fluid which flows in the main duct 9 with respect to the outside of the external wall 10, also with a simplification in terms of manufacturing. Still furthermore, according to a further alternative not shown, the first hollow layer 11 is filled with insulating material.

[0115] Advantageously, the present solution may be optimized with respect to specific application requirements, by varying the adopted insulating material.

[0116] As visible in Figures 5-7, according to different embodiments of the invention, the external wall 10 comprises a second hollow layer 13, which is preferably parallel, or coaxial to the first hollow layer 11.

[0117] The presence of a second hollow layer 13 obviously amplifies the insulation effects of the main duct 9 and of the related cryogenic fluid which flows therein with respect to the external environment.

[0118] In order to optimize the operation, according to an embodiment schematically shown in Figure 5, the second hollow layer is filled with thermally insulating material.

[0119] The thermally insulating material can be selected for example, but not limitedly, from bubble glass, PTFE, which has also a structural function, perlite powder, aerogel, etc.

[0120] This solution, for example when in combination with the first described embodiment, delays the evaporation condition of the working fluid which flows inside the first hollow layer 11 , and therefore forms a further shield for the temperature variations determined by the conditions outside the pump 1, 1’.

[0121] According to an alternative embodiment, shown in the schematic drawing of Figure 6, downstream of the at least one impeller 5 and the branch 12 of the working flow, a second purge branch is provided, adapted to convey a second fraction of first cryogenic fluid into the second hollow layer 13.

[0122] In this case too, nothing prevents to provide a different generic flowing direction of the cryogenic fluid. Therefore, this solution exploits the same principle of the first embodiment, i.e. the change of state of a small quantity of fluid so as not to affect the operating conditions of the fluid in the main duct 9, doubling the effects with the adoption of two layers 11, 13.

[0123] According to an alternative embodiment, shown in the schematic drawing of Figure 7, the external wall 10 is made with the second hollow layer 13 under vacuum conditions.

[0124] In other words, the features proposed in the first embodiment and in one of the alternatives thereof are here combined, in order to exploit on the one hand an optimal thermal insulation and on the other a better manufacturing effectiveness.

[0125] The material which is present between the first hollow layer 11 and the second hollow layer 13 and the material adopted for the outermost layer of the external wall 10, which is adjacent to the second hollow layer 13 and opposite to the main duct 9, may be equal or different, depending on the features of the cryogenic fluid acting as a working fluid and on the related needs in terms of thermal insulation.

[0126] In the embodiment represented in the schematic drawing of Figure 8, the outermost layer of the external wall 10 consists of a layer 14 of insulating material, a material which can be selected for example from glass fiber, PTFE, which has also a structural function, aerogel, etc. However, in an alternative not represented, this layer 14 of insulating material can be adopted even in the presence of only the first hollow layer 11 , without necessarily the presence of the second hollow layer 13.

[0127] In the selection of an insulating material, nothing prevents to alternatively adopt a cover of a layer of material by means of a powder, a foam or different particles which give these thermal insulation features to this layer.

[0128] In addition, nothing prevents to combine various above-described solutions, even increasing the number of layers provided in the external wall 10.

[0129] For example, it is possible to adopt a second layer 13 under vacuum conditions with an insulating layer 14, or even differently associate the various above-described layers.

[0130] Furthermore, in an embodiment not represented, the pump 1 can provide that at least the first hollow layer 11 continues with a solution of continuity both in the first portion 3 and in the second portion 4, ensuring a thermal insulation of the cryogenic fluid which flows in the pump 1 along the entire longitudinal development thereof up to the outlet thereof, i.e. up to the coupling interface with a motor, with a second pump, or with a turbine, or any component, sub-system or system adapted to supply the mechanical energy to the shaft.

[0131] Obviously, nothing prevents to provide a different solution in the second portion 4 of the casing 2, as well as nothing prevents to combine different embodiments according to the present invention between the first portion 3 and the second portion 4 of the casing 2.

[0132] The new design according to the present invention of the casing 2 of the pump 1, according to the different embodiments described or obvious alternatives thereof, can be manufactured through a traditional CNC numerical control machining process, i.e. a “subtractive” manufacturing process which uses computerized controls and machine tools to remove layers of material from a rough piece, a process which is generally more complex and more expensive, or through an additive manufacturing process.

[0133] According to a further aspect of the invention, as visible in Figure 9, a system 15 is provided, comprising a pump 1 according to the above description with exemplary reference to what is described in Figure 2, and at least one electric motor 16 comprising an external case comprising an external wall with a layered structure which is similar to that of the pump. Advantageously, it is possible to extend and associate the insulation properties of the present invention even to the external case of the at least one electric motor 16 connected to the pump 1, 1’.

[0134] It is emphasized that the pump 1, 1’ according to the present invention allows to overcome the drawbacks of known solutions, primarily it ensures maintaining the optimal thermal, fluid dynamic and pressure working conditions for the working fluid in cryogenic conditions which flows inside the pump 1, 1’.

[0135] Moreover, advantageously, it is possible to save in terms of time in the manufacturing of a similar solution compared to the adoption of a more complex manufacturing equipment of the currently available prior art solutions.

[0136] Compared to the latter, a greater economy of the overall system at the end of all expected manufacturing costs may be found as well.

[0137] Furthermore advantageously, a smaller number of overall components is found, which has an impact not only on costs but also on overall robustness, maintenance, reliability, etc.

[0138] Moreover, it is possible to find a certain adaptability of the possible alternatives depending on the specific requirements, alternatives which find an immediate application through a programming variation according to the above-exemplified manufacturing modes.

[0139] Obviously, in order to meet contingent and specific requirements, a person skilled in the art will be allowed to bring several modifications and alternatives to the above-described pump, all comprised in the scope of protection of the invention as defined by the following claims.

[0140] For example, different materials may be adopted depending on the operating and cost requirements of each specific application, as well as the solution according to the attached claims may be adopted in different types of pumps compared to those represented here, also depending on the future technological development of the space sector, or of that concerning cryogenic pumps, or other sectors of application of the present invention.

[0141] Moreover, as mentioned, it is possible to combine the various above- described layers relative to the external wall 10, in order to achieve different features depending on the specific and contingent requirements of the desired application.

Claims

CLAIMS1. A high-performance pump (1, 1’) for a first cryogenic fluid comprising: a casing (2) which develops along a flow direction of said first cryogenic fluid; at least one impeller (5); a shaft (A) connected and adapted to actuate said at least one impeller (5); said casing (2) comprising a first portion (3) and a second portion (4), said second portion (4) being adapted to contain said shaft (A) and which said at least one impeller (5) protrudes from, said first portion (3) being in extension of said second portion (4) at said at least one impeller (5); at least said first portion (3) of said casing (2) comprising: a main through-duct (9) comprised between an inlet (8) of said pump (1, 1’) and said at least one impeller (5), said main duct (9) being adapted to bring said first cryogenic fluid from said inlet (8) to said at least one impeller (5); an external wall (10) defining said main duct (9), said external wall (10) comprising a layered structure and at least one first hollow layer (11), said at least one first hollow layer (11) being provided along the longitudinal development of said first portion (3) of said casing (2) in the flow direction of said first cryogenic fluid.

2. The pump (1) according to claim 1, comprising at least one connection branch (12) downstream of said at least one impeller (5), said branch (12) being adapted to convey a first fraction of said first cryogenic fluid into said first hollow layer (11).

3. The pump (1’) according to claim 1, comprising at least oneconnection branch (12’) upstream of said at least one impeller (5), said branch (12’) being adapted to convey a first fraction of said first cryogenic fluid into said first hollow layer (11).

4. The pump (1, 1’) according to claim 1, wherein said first hollow layer (11) provides an alternative inlet to supply a second cryogenic fluid, which is different from said first cryogenic fluid, to said first hollow layer (11).

5. The pump (1, 1’) according to claim 1, wherein said external wall (10) is made with said first hollow layer (11) under vacuum conditions.

6. The pump (1, 1’) according to claim 1, wherein said first hollow layer (11) is filled with insulating material.

7. The pump (1, 1’) according to any one of claims 1 to 6, wherein said external wall (10) comprises a second hollow layer (13), which is preferably parallel or coaxial to said first hollow layer (11).

8. The pump (1, 1’) according to claim 7, wherein said external wall (10) is made with said second hollow layer (13) filled with thermally insulating material.

9. The pump (1) according to claim 7, comprising a second purge branch adapted to convey a second fraction of first cryogenic fluid into said second hollow layer (13).

10. The pump (1, 1’) according to claim 7, comprising a second inlet for said second hollow layer (13), said second inlet being adapted to allow the introduction of a second cryogenic fluid.

11. The pump ( 1 , 1 ’) according to claim 7, wherein said external wall (10) is made with said second hollow layer (13) under vacuum conditions.

12. The pump (1, 1’) according to any one of claims 1 to 11, wherein said external wall (10) comprises an insulating layer (14) which is adjacent to said first hollow layer (11) or to said second hollow layer (13) and opposite to said main duct (9).

13. The pump (1, 1’) according to any one of claims 1 to 12, wherein said at least one first hollow layer (11) is made with a solution of continuity in said first portion (3) and in said second portion (4) of said casing (2).

14. A system (15) comprising one or more pumps (1, 1’) according to any one of claims 1 to 13, and at least one electric motor (16) comprising an external case comprising an external wall with a layered structure which is similar to said pump ( 1 , 1 ’) .

15. The system (15) according to claim 14, further comprising at least one turbine, or any component, sub-system or system adapted to supply mechanical energy to at least one shaft (A) of said one or more pumps (1, !’)•

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