DESCRIPTION

Field of the invention

The present invention has as its object a turbomachine and an apparatus comprising said turbomachine. The present invention is in the field of the turbomachines which comprise at least a portion, for example one or more stages, of “bladeless” type, or without vanes. Preferably, the present invention is in the field of turbomachines used in the field of apparatuses for the conversion of energy, for example but not necessarily apparatuses configured for realizing refrigeration cycles.

State of the art

There are known turbomachines without vanes (bladeless) which use rotors provided with spiral channels wherein passes a working fluid to obtain an energy exchange between said working fluid and said rotor.

For example, the document CN201610943536 shows a steam turbine which comprises a spiral channel connected integrally with a rotor.

The document US2655868 shows a centrifugal pump comprising a rotor in which it is fashioned a spiral channel with at least a helical spiral.

The document US2544154 shows a tubular turbine which comprises a variable diameter conduit having a plurality of convolutions disposed as helix.

The document ES2365663A1 shows a turbine which comprises radial ridges among which are fashioned openings of passages obtained in the turbine and inclined.

The document US4603549A shows a turbine motor having helical tubes.

Object of the invention

In this field, the Applicant set itself the objective of using the principle of “bladeless” turbomachines “bladeless” to propose a more compact and efficient turbomachine and usable in different fields for the conversion of energy.

The Applicant set itself in particular the purpose of proposing a turbomachine integrating different stages and/or functions (for example: expander and compressor or different stages of expansion and/or compression).

The Applicant set itself also the purpose of proposing a compact and then easily positionable turbomachine in apparatuses for the conversion of energy. i The Applicant set itself also the purpose of proposing a structurally easy and then also relatively cheap and reliable turbomachine.

Summary of the invention

The Applicant has found that these objectives and purposes can be obtained by realizing a turbomachine according to the present invention, of the type claimed in the attached claims and/or described in the following aspects.

In particular, the turbomachine according to the present invention integrates a traditional bladed turbomachine with a turbomachine without vanes, or of “bladeless” type.

According to a first aspect, the present invention is related to a turbomachine, comprising: a case; a rotor positioned in the case so that it can rotate with respect to the case around its own longitudinal axis; wherein the rotor comprises:

- at least one blading mounted on the rotor and arranged in a respective transit volume bounded between the rotor and the case for the passage of a first working fluid;

- at least one helical conduit developing in loops around the longitudinal axis and extending between at least one inlet and at least one outlet for the passage of a second working fluid; wherein said at least one helical conduit is radially internal with respect to said at least one blading and has loops with gradually increasing or decreasing radial dimensions from the inlet towards the outlet.

The transit volume is the passage occupied by the blading and through which passes the first working fluid while it interacts with the blading and with any statoric parts of the turbomachine.

According to a second aspect it is relative to an apparatus for the conversion of energy comprising a turbomachine according to the preceding first aspect and/or second one or more of the aspects hereinafter described.

In the present description and in the attached claims, with the term “blading” is generally intended an assembly of elements or an appropriately shaped element which rotates/rotate with the rotor and which interacts/interact with the working fluid to transform the energy of the fluid into the mechanical energy of rotation of the rotor or vice versa. Unless otherwise specified therefore the blading can comprise vanes, blades, lobes, the profile of a screw, scroll geometry, etc., and can act as an expander/turbine or compressor/pump. The Applicant has verified that the integration of the traditional bladed turbomachine with the bladeless turbomachine, according to the invention shown in the claims and in the listed aspects, allows to realize a multiplicity of functions of expansion and/or compression with minimum overall dimensions.

The Applicant has verified that the compactness of the turbomachine according to the invention allows its easy installation in apparatuses for the conversion of energy of different type and dimension.

The Applicant has also verified that the turbomachine according to the invention is, further than compact also structurally easy and then also reliable and relatively cheap.

The Applicant has furthermore verified that the turbomachine according to the invention allows to improve the efficiency of apparatuses wherein it is installed.

Further aspects of the invention are listed below.

In an aspect, said at least one blading and said at least one helical conduit are integral to each other and rotate together around the longitudinal axis.

In an aspect, said at least one blading is disposed on a radially outer surface of the rotor.

In an aspect, said at least one helical conduit is radially internal with respect to said at least one blading.

In an aspect, said at least one helical conduit is radially internal with respect to said radially outer surface.

In an aspect, the rotor is a solid body and said at least one helical conduit is fashioned in the solid body.

In an aspect, the rotor is realized in metal, for example steel, stainless steel (for example, martensitic or austenitic), alloys of nickel, aluminum, or in plastic, in composite or organic materials, depending on the use.

In an aspect, the rotor is realized by means of 3D printing, casting, machining, for example by milling or EDM (Electrical Discharge Machining) depending on the material chosen for its fabrication.

In an aspect, the rotor comprises at least two sectors firmly joined together, for example by welding or diffusion bonding or mechanical connections.

In an aspect, in each of the sectors is fashioned at least a tract of said at least one helical conduit.

In an aspect, said at least one inlet is located on the radially outer surface of the rotor.

In an aspect, the turbomachine comprises a shaft integral with the rotor.

In an aspect, the shaft is rotatably supported in the and/or by the case.

In an aspect, bearings are interposed between the case and the shaft for permitting to the rotor to rotate in the case.

In an aspect, the rotor is located at an end of the shaft and therefore supported overhanging in the case. In an aspect, the rotor is located between opposite ends of the shaft, each end being supported in the case.

In an aspect, the shaft is connected to an electric motor and/or to an electric generator.

In an aspect, the shaft supporting the rotor is the shaft of the motor and/or of the electric generator which passes through the case.

In an aspect, the shaft is rotatably supported by bearings of the motor or of the electric generator.

In an aspect, the rotor comprises a first part supporting the blading and a second part defined by a shaft or comprising a shaft or fitted on a shaft.

In an aspect, the first part and the second part are separated elements and connected to each other, optionally through screws, welds or Hirth teeth.

The realization in two parts allows to optimize the production and the costs.

For example, the second part can be realized with 3D printing and the first part through milling. The first and the second part can be realized with the same material or in different materials, for example in such a way as to optimize the strength according to their different load and temperature conditions. The realization of the rotor with the first part and the second part allows to thermally disconnect the two parts. For example, in case of turbopumps for space propulsion: the second part (inner) would be at - 200 °C whereas the first part (outer) at 600 °C. Furthermore, in this way it is possible to intervene (carry out an upgrade) on already existing turbomachines, for example, on refrigeration compressors, by modifying the compressors already functioning and adding directly the “bladeless” part.

The two disconnected parts are free to move in a limited way the one with respect to the other, for example along the Hirth, and these relative movements allow to avoid breakings two to thermal stresses which, in case of realization in a solid body, are related to the prevented deformations.

The realization of the rotor in two parts allows also to optimize the maintenance: it is possible to replace the two parts singularly.

In an aspect, said at least one helical conduit is obtained in the first part or in the second part or is obtained both in the first part and in the second part.

In an aspect, the first part is fitted on the shaft.

In an aspect, a plurality of first parts are fitted on a common shaft so as to realize a plurality of turbomachines.

In an aspect, the helical conduits of the turbomachines are connected to each other in series or in parallel.

In an aspect, the transit volumes of the turbomachines are connected to each other in series or in parallel.

In an aspect, the rotor has at least one empty portion to lighten said rotor. In an aspect, said at least one empty portion is inner to the rotor or fashioned on an outer surface of the rotor.

In an aspect, the rotor or at least a part thereof has a honeycomb structure, for example realized through 3D printing.

In an aspect, said at least one outlet is located on a head surface of the rotor.

In an aspect, said at least one inlet is located near a first end of the rotor.

In an aspect, said at least one outlet is located near a second end of the rotor opposite the first end.

In an aspect, the rotor comprises a plurality of helical conduits.

In an aspect, the rotor has a plurality of inlets of the helical conduits, one for each conduit or also a plurality of inlets for each conduit.

In an aspect, the rotor has a plurality of outlets of the helical conduits, one for each conduit or also a plurality of outlets for each conduit.

In an aspect, different helical conduits are positioned in different axial areas of the rotor.

In an aspect, different helical conduits are positioned in same axial areas of the rotor.

In an aspect, said at least one helical conduit has a constant or variable section of passage along its own development.

In an aspect, the section of said at least one helical conduit has a circular or triangular or elongated or T-shape.

In an aspect, different helical conduits have respective inlets or outlets disposed near a central axial portion of the rotor and respective outlets or inlets disposed on opposite ends of the rotor or of the shaft.

In an aspect, the rotor has inlet series of the helical conduits.

In an aspect, each series comprises a plurality of inlets circumferentially disposed around the rotor.

In an aspect, each series is in fluid connection with a respective helical conduit and at least some of said helical conduits join together or remain separated until said at least one outlet.

In an aspect, the series are positioned in different axial positions.

In an aspect, the rotor has circumferential surfaces with different diameters and each series is positioned on one of said circumferential surfaces.

In an aspect, said at least one blading comprises a plurality of vanes.

In an aspect, said at least one inlet and/or said at least one outlet is/are disposed between vanes of the blading so as to modify a boundary layer of the first working fluid.

In an aspect, said at least one blading defines at least one profile of a screw.

In an aspect, said at least one blading in the transit volume defines one or is part of a for example bladed, lobe, screw, spiral or also scroll type compressor or a pump. In an aspect, said at least one blading in the transit volume defines one or is part of a bladed expander. In an aspect, said at least one helical conduit is an expander without vanes (bladeless), for example a turbine without vanes.

In an aspect, said at least one helical conduit is a compressor or a pump without vanes (bladeless).

In an aspect, the bladed expander is a turbine, optionally an axial, radial or radial/axial or axial/radial mixed flow turbine.

In an aspect, the bladed compressor is a radial, axial or radial/axial or axial/radial mixed flow compressor.

In an aspect, said at least one blading located in the transit volume and said at least one helical conduit are part of a same circuit and the first working fluid and the second working fluid are the same working fluid.

In an aspect, said at least one blading located in the transit volume and said at least one helical conduit are part of separated circuits and the first working fluid and the second working fluid can be different fluids.

In an aspect, the first working fluid is a gas, a steam, a liquid, for example a coolant, oxygen, hydrogen. In an aspect, the second working fluid is a gas, a steam, a liquid, for example liquid oxygen, hydrogen, liquid hydrogen.

In an aspect, the case has a diffuser placed around the rotor and in fluid communication with an outlet of the transit volume.

In an aspect, the case has a diffuser placed around the rotor and in fluid communication with the outlet of said at least one helical conduit.

In an aspect, the case has a distributor placed around the rotor and in fluid communication with an inlet in the transit volume.

In an aspect, the case has a distributor placed around to the rotor and in fluid communication with the inlet of said at least one helical conduit.

In an aspect, the diffuser and the distributor are side by side and separated the one from the other by a septum of the case.

In an aspect, the distributor comprises a plurality of directional blades, optionally said blades are orientable and the turbomachine is adapted to work with partial or variable loads.

In an aspect, the distributor is configured for inserting the second working fluid through one or more of the inlet series according to the load (so as to work with partial or variable loads).

In an aspect, the case comprises a plurality of statoric vanes cooperating with said at least one blading in the transit volume.

In an aspect, the apparatus for the conversion of energy is a refrigeration apparatus or heat pump. In an aspect, the turbomachine is used as turbocharger in a gas cycle (gas turbines or turbogas) or in a steam cycle (as turbopump).

In an aspect, said turbomachine is a turbine or a compressor or a turbocharger or a turbopump.

In an aspect, the refrigeration apparatus comprises:

- at least one condenser;

- at least one evaporator;

- at least one turbomachine according to the preceding aspect, i.e. a turbocharger;

- an electric motor connected to the rotor of the turbomachine;

- ducts connecting said at least one condenser, said at least one evaporator and said at least one turbomachine to form a refrigeration circuit; wherein the ducts connect said at least one condenser and said at least one evaporator to said at least one turbomachine so as to compress a working fluid circulating in the refrigeration circuit before it enters said at least one condenser and to expand said working fluid before it enters said at least one evaporator.

In an aspect according to the preceding aspect, said at least one evaporator has an inlet and an outlet, said at least one condenser has an inlet and an outlet; the blading in the transit volume defines a or is part of a compressor and said at least one helical conduit is a expander; the outlet of the condenser is connected to the inlet of said at least one helical conduit and the inlet of the condenser is connected to an outlet of the transit volume; the outlet of the evaporator is connected to an inlet of the transit volume and the inlet of the evaporator is connected to the outlet of said at least one helical conduit.

The Applicant has verified that the adoption of the turbomachine (turbocharger) according to the invention in the refrigeration apparatus allows to reduce the consumptions and/or to increase the refrigeration power (or heat generation power if used as a heat pump), i.e. to improve the efficiency.

The Applicant has also verified that, if the turbomachine is a turbopump for aerospatial propulsors, it allows a saving of dimensions (is more compact), of weight and, given that there are liquids, the pump without vanes according to the invention has a better performance than the traditional bladed pumps.

Brief description of figures

Other characteristics and advantages will be clearer from the detailed description of the preferred but non-exclusive embodiments, of a turbomachine according to the present invention and of an apparatus comprising said turbomachine.

This description will be hereinafter indicated with reference to the attached drawings, given only as indicative purpose and, therefore, non-limiting, wherein:

- Figure 1 is a sectional view of a turbomachine according to the present invention; - Figure 2 is a tridimensional view of the turbomachine of figure 1 ;

- Figure 3 is an exploded view of the turbomachine thereof in figures 1 and 2 in an assembling step;

- Figure 4 is a rear view of the rotor of the turbomachine of the preceding figures;

- Figure 5 shows schematically a refrigeration apparatus according to the invention;

- Figure 6 shows a refrigeration cycle carried out by the apparatus of figure 5 compared with a traditional refrigeration cycle;

- Figure 7 is a sectional view of a variant of the turbomachine according to the invention;

- Figure 8 is a sectional view of another variant of the turbomachine according to the invention;

- Figure 9 is a sectional view of another variant of the turbomachine according to the invention;

- Figure 10 is a sectional view of another variant of the turbomachine according to the invention;

- Figures from 11 to 14 schematically show embodiments of rotors of the turbomachine according to the invention;

- Figure 15 is a schematic rear view of a rotor of the turbomachine according to the invention;

- Figure 16 shows another variant of the turbomachine of figure 1 ;

- Figures from by 17 to 26 show other variants of the rotor implementable in a turbomachine according to the present invention.

Detailed description of preferred embodiments of the invention

With reference to the attached figures, with 1 it has been overall indicated a turbomachine according to the present invention.

In the embodiment shown in figures from 1 to 3, this turbomachine 1 is a turbocharger which integrates a centrifugal compressor with axial/radial mixed flow and a turbine without vanes i.e. of “bladeless” type.

The turbomachine 1 comprises a case 2 which comprises a central portion 3 which delimits a housing for a rotor 4 and a sleeve 5 which extends overhanging from a side of the central portion 3. A tubular body 6 develops overhanging from a side of the central portion 3 opposite to the one connected to the sleeve 5.

The rotor 4 comprises a cylindrical base 7 with circular section with higher diameter which thins out in a distal portion 8 with circular section of lower diameter. A radially outer surface 9 of the rotor 4 diverts from the distal end 8 towards the cylindrical base 7 and brings a blading defined by a plurality of vanes 10 with heights that decrease from the distal end 8 towards the cylindrical base 7. The vanes 10 are curved and follow the profile of the radially outer surface 9. A wall of the case 2 is positioned near the vanes 10 and delimits together with the radially outer surface 9 of the rotor 4 a transit volume 11 for the passage of a first working fluid. A section of said volume of passage decreases by moving from the distal end 8 towards the cylindrical base 7, i.e. starting from an inlet 12 of the transit volume 11 towards an outlet 13 of said transit volume.

The rotor 4 is a solid body and has furthermore a helical conduit 14 obtained inside it. The helical conduit 14 develops in loops around a longitudinal axis “X-X” of the rotor 4 or rotation axis of the rotor 4. The helical conduit 14 has a plurality of inlets 15 defined by respective holes fashioned on the radially outer surface of the rotor 4 near the cylindrical base and an outlet 16 fashioned on a head surface of the distal portion 8 of the rotor 4. For example but not necessarily, the outlet 16 is axial, i.e. parallel to the longitudinal axis “X-X”.

The helical conduit 14 develops in loops around to the longitudinal axis “X-X” and extends between the plurality of inlets 15 and the outlet 16 according to a plurality of loops which have gradually decreasing radial dimensions starting from the inlets 15 towards the outlet 16. The inlets 15 are for example all connected to the first loop of greater dimensions, as shown in Figure 4.

The helical conduit 14 is radially internal with respect to the blading and to the radially outer surface 9 of the rotor 4 and is configured for allowing the passage of a second working fluid.

The helical conduit 14 uses also the friction force exchanged between an inner surface of said helical conduit 14 and the second working fluid to transfer power/force between said fluid and the rotor 4. The turbomachine 1 comprises a shaft 17 integral with the rotor 4 and developing from the cylindrical base 7 coaxially to the longitudinal axis “X-X”. The shaft 17 is installed in the sleeve 5 of the case 2 through bearings 18 so that it can rotate around the longitudinal axis “X-X”. The bearings 18 support the shaft 17 and support overhanging the rotor 4 in the case 4, being disposed only on a side of the rotor 4 whereas the distal portion 8 is not supported by the case 4 but protrudes overhanging.

In embodiment variants, the rotor 4 can be connected to a motor and/or to an electric generator.

In these variants, the shaft 17 can also be the shaft of the motor/generator which passes through an opening in the case 2 and carries the rotor 4. In these variants, the shaft is then supported by bearings of the motor/generator instead of bearings 18 placed in the case 4.

The rotor 4 is a solid body and then the vanes 10 and the helical conduit 14 are integral to each other and, when the rotor 4 rotates, rotate together around the longitudinal axis “X-X”.

The central portion 3 of the case 2 delimits a diffuser 19 and a distributor 20 disposed around the cylindrical base 7. The diffuser 19 surrounds and is in fluid communication with the outlet 13 of the transit volume 11 . The distributor 20 surrounds and is in fluid communication with the inlets 15 of the helical conduit 14. The diffuser 19 and the distributor 20 are fashioned in a loop 21 located around the cylindrical base 7 and are separated the one from the other by a septum 22. The septum 22 is connected to a radially peripheral wall of the loop 21 and has a radially internal edge thereof placed in proximity of the cylindrical base 7. The edge is provided with a gasket or a mechanical seal which prevents leakages between the diffuser 19 and the distributor 20. Optionally, in the diffuser 19 are placed fixed blades 23 and in the distributor 20 are placed directional blades 24. The directional blades 24 can be oriented as a function of the flow rate and the turbomachine 1 is so adapted to work with partial or variable loads.

Radial supports 25 disposed in the tubular body 6 carry an internal tubular body 26 positioned in front of the distal portion 8 and coaxial to the longitudinal axis “X-X” of the rotor 4 to receive the second working fluid exiting from the outlet 16 of the helical conduit 14 and allow its leakage from the case 2 through a first outlet 27 from said case 2.

A first inlet 28 in the case 2 is bounded between the tubular body 6 and the internal tubular body 26 and allows to the first working fluid to enter through the inlet 12 of the transit volume 11 . The loop 21 has a respective second inlet 29 in the case 2 which inserts in the distributor 20 and a second outlet 30 for the leakage of the first working fluid from the diffuser 19. Then, the first working fluid axially enters in the case 2 through the first inlet 28, passes through the transit volume 11 with the vanes 10, flows in the diffuser 19 and then exits from the second outlet 30. The second working fluid enters along a direction substantially perpendicular to the longitudinal axis ‘X-X” in the second inlet 29 of the case 2, passes in the distributor 20, flows through the helical conduit 14, and exits axially through the first outlet 27.

As it will be more evident hereinafter, the vanes 10 in the transit volume define the axial/radial mixed flow centrifugal compressor and the helical conduit 14 defines the turbine “bladeless”.

In the example of embodiment of figures 1 - 4, the case 2 is formed by a first body and a second body. The first body comprises the tubular body 6, the internal tubular body 26, the radial supports 25, the central portion 3 with the loop 21 and the septum 22. The second body comprises the sleeve 5 and a rear wall 31 from which protrudes the sleeve 5 and which closes the first body.

The turbomachine 1 can be mounted by inserting the shaft 17 with the bearings 18 in the sleeve 5 and then by axially approaching between them the first body to the second body with the rotor 4 and joining the rear wall 31 to the first body, as shown in figure 3.

In realization variants, not shown, the case 2 can be instead divided into two halves according to a plane which contains the longitudinal axis “X-X”.

Figure 5 schematically shows a refrigeration apparatus 32 in which it is used the turbomachine 1 above described. In this figure 5, the turbomachine 1 is schematically represented. Said turbomachine 1 is a turbocharger. The blading in the transit volume 11 defines the compressor and the helical conduit 14 is the “bladeless” expander, i.e. the turbine. The refrigeration apparatus 32 comprises the turbomachine 1, one evaporator 33, one condenser 34. The shaft 17 of the rotor 4 of the turbomachine 1 is connected to an electric motor 35. Conduits connect between them the turbocharger 1 , the evaporator 33 and the condenser 34 and contain a working fluid, a cooling fluid, so as to form a refrigeration circuit and to define the refrigeration apparatus 32 configured for actuating a refrigeration cycle.

The first working fluid and the second working fluid indicated with different names in the detailed description of the turbomachine 1 of figures 1 - 4 coincide, i.e. only one working fluid circulates in the refrigeration circuit of figure 5 and then through the axial/radial mixed flow centrifugal compressor and through the helical conduit 14 which defines the turbine “bladeless”.

In figure 5 the evaporator 33 has an inlet 36 and an outlet 37, the condenser 34 has an inlet 38 and an outlet 39.

The outlet 39 of the condenser 34 is connected to the second inlet 29 of the case 2 and then to the inlets 15 of the helical conduit 14 and the inlet 38 of the condenser 34 is connected to the second outlet 30 of the case 2 and then to the outlet 13 of the transit volume 11 . The outlet 37 of the evaporator 33 is connected to the first inlet 28 of the case 2 and then to the inlet 12 of the transit volume 11 and the inlet 36 of the evaporator 33 is connected to the first outlet 27 of the case 2 and then to the outlet 16 of the helical conduit 14. The working fluid circulating in the refrigeration circuit is compressed in the compressor actuated by the electric motor 35 before entering in the condenser 34 and is expanded in the “bladeless” expander/turbine before it enters in the evaporator 33.

The attached figure 6 shows the refrigeration cycle actuated by the apparatus 32 according to the invention here described (continuous line) and a refrigeration cycle actuated by a traditional apparatus (dashed line), wherein instead of the turbocharger 1 of the present invention there is a compressor and a lamination/expansion valve, i.e. instead of in the turbine according to the invention, the working fluid is expanded through the lamination/expansion valve.

According to the traditional cycle, the working fluid is compressed in the compressor from A to B, then cools and condenses in the condenser from B to C, then expands in the lamination valve from C to D and evaporates in the evaporator from D to A.

According to the cycle operated by the apparatus 32 of the invention, the working fluid is compressed in the compressor from A to B, then cools and condenses in the condenser 34 from B to C, then expands in the “bladeless” turbine from C to D’ and evaporates in the evaporator 33 from D’ to A.

As it can be seen, the two cycles are substantially superimposed except in the zone/step of expansion C-D, C-D’ so the area enclosed by the refrigeration cycle operated by the apparatus 32 according to the invention is greater than the area enclosed by the traditional cycle, so it involves a specific work greater in absolute value. Furthermore, it comes closest to an ideal cycle. The Applicant has observed which already in small domestic applications and with a turbine of performance higher than 60%, the invention allows to reduce the consumptions of about the 20-25%, further than increase the refrigeration power of a few percentage points (up to 15-20%). These benefits become more significant the greater are the performance of the turbine and the difference of temperature between the hot source and the cold source.

Figure 7 is a sectional view of a variant of the turbomachine 1 according to the invention which differs from the turbomachine shown in figures 1 - 4 because the rotor 4 is not supported overhanging. In fact, the shaft 17 comprises furthermore an end 40 which extends starting from the distal portion 8 of the rotor 4 and is supported in the case 2 by bearings 18 housed in a body 41 in its turn supported by radial supports 42 disposed in the tubular body 6. The helical conduit 14 extends also within said end 40 of the shaft 17 and ends on the ending side of said end 40 placed at the internal tubular body 26. Figure 8 is a sectional view of another variant of the turbomachine 1 according to the invention which differs from the turbomachine shown in figures 1 - 4 because the compressor is of axial flow type, i.e. vanes 10 radially develop starting from the distal portion 8 of the rotor 4 with decreasing heights from the inlet 12 towards the outlet 13 of the transit volume 11 .

Another variant, not shown, has the structure of the compressor of figure 8 and the end 36 of the shaft 17 supported by bearings 18 as in figure 7.

Also the variants of figures 7 and 8 can comprise a case 2 divided as in figure 3 or divided according to a plane which contains the longitudinal axis “X-X”.

Figure 9 is a sectional view of another variant of the turbomachine 1 according to the invention which differs from the turbomachine shown in figures 1 - 4 for the arrangement of the second inlet 29 and of the second outlet 30 on the case 2. The second inlet 29 is arranged diametrically opposite with respect to the second outlet 30 and the flows of the inlet working fluid in inlet in the second inlet 29 and in outlet from the second outlet 30 are substantially radial with respect to the longitudinal axis “X-X”. In another variant, not shown, the second inlet 29 and the second outlet 30 are side by side so as the flows are always radial.

Figure 10 is a sectional view of another variant of the turbomachine 1 according to the invention which differs from the turbomachine shown in figures 1 - 4 for the presence of a passage 43 for atmospheric air fashioned between two distinct loops, one which delimits the diffuser 19 which surrounds and is in fluid communication with the outlet 13 of the transit volume 11 and the other which delimits the distributor 20 which surrounds and is in fluid communication with the inlets 15 of the helical conduit 14. The same passage 43 can also be obtained between the second inlet 29 and the second outlet 30 which are side by side so as the inlet and outlet flows are radial. In other embodiments falling within the scope of the present invention the arrangement and the geometry of the blading in the transit volume 11 and also the number and the arrangement of the helical conduits 14 may differ from those described above.

For example, the blading in the transit volume defines an expander instead of a compressor and the helical channel defines a compressor or a pump instead of an expander. In this case, the diffuser is in fluid communication with the outlet of the helical conduit and the distributor is in fluid communication with the inlet in the transit volume.

For example, said blading is subdivided in different sections with different functions and each comprising one or more stages (see figure 11 which shows two turbines with vanes 10 and a “bladeless” compressor defined by the helical conduit 14). The case 2 can comprise a plurality of statoric vanes 44 the vanes 10 cooperating in the transit volume 11 (for example as in figure 11). Said blading can define at least one profile of a screw instead of comprising a plurality of different vanes.

If the helical channel is used as a compressor, then the loops have gradually increasing radial dimensions starting from the inlet or inlets 15 towards the outlet 16 or the outlets 16 (see figure 11 ).

The rotor 4 can also comprise a plurality of helical conduits 14 which extend into the same axial zones of the rotor 4, i.e. for example along the whole axial development of it as in figure 13 (which shows a compressor with vanes 10 and two “bladeless” turbines each defined by a respective helical conduit 14), or which extend in different axial zones of the rotor 4 (see figure 12 which shows two turbines with vanes 10 two “bladeless” turbines each defined by a respective helical conduit 14).

Each helical conduit 14 can have one inlet 15 or a plurality of inlets 15 and/or one outlet 16 or a plurality of outlets 16. The inlet 15 or the inlets 15 can be arranged at a first end of the rotor 4 or in an intermediate zone thereof, as for example in figure 12. Similarly, the outlet 16 or the outlets 16 can be arranged at a second end of the rotor 4 or in an intermediate zone thereof.

The outlet or the outlets 16 can be oriented parallel to the longitudinal axis “X-X” (axial outlets) or can have an angle of inclination with respect to said longitudinal axis “X-X”.

The rotor 4 can also be lightened by removing unnecessary material both externally and internally. For example, the portion of the rotor 4 radially located inside with respect to the loops of the helical conduit 14 (or of the helical conduits), i.e. where the loops are not present, can be lightened by removing material and obtaining one or more empty rooms. The rotor or at least a part thereof can furthermore have a honeycomb structure so as to lighten it and at the same time ensure an adequate rigidity thereof.

Regardless of the specific geometry adopted, the material with which the turbomachine 1 is realized is chosen according to the specific requirement. For example, the rotor 4 is realized in metal, for example steel, martensitic or austenitic stainless steel, alloys of nickel, aluminum, or also in plastic material, composite or organic materials.

If the rotor is in metal, it is preferable to realize it by casting, through mechanical machining, such as milling or electroerosion (EDM - Electrical Discharge Machining) or also 3D printing. If the rotor is in plastic material, it can for example be realized through 3D printing.

The rotor 4 can be realized in a solid body or in a plurality of sectors 45 then joined together, as schematically shown in figure 14. In each sector 45 is obtained a tract of the channel or of the helical channels 14. Each of the sectors 45 can be produced by casting, through mechanical machining, such as milling or electroerosion or 3D printing. If realized in metal, these sectors 45 are for example joined together through welding or diffusion bonding or through other mechanical connections.

Furthermore, the rotor 4 can be geometrically studied and realized to optimize the inlet or the inlets 15 and/or the outlet or the outlets 16. For example, as shown in figure 15, an outer surface of the rotor 4 forms, at least at the inlets 15, steps so that said inlets 15 are fashioned on surfaces of the rotor 4 which are not coaxial to the longitudinal axis “X-X”. The inlets 15 are not oriented along radial directions but form an angle other than zero with respect to radial directions passing by the respective inlet point. Furthermore, the section of passage of each helical channel 14 can take on different dimensions and shapes (for example circular, triangular, elongated, T-shaped, etc.) and be constant or vary along its development.

Figure 16 shows another variant of the turbomachine of figure 1 which differs from the turbomachine of figure 1 because the case 2 comprises an auxiliary loop 46 arranged at the end of the tubular body 6. The first inlet 28 is obtained on said auxiliary loop 46 and the radial supports 25 are not present. In this way the case 2 is easier (there are no radial supports 25) and is completely prevented that the flow entering the compressor mixes with the fluid exiting from the turbine.

The turbomachine 1 according to the invention can furthermore be used in apparatuses different than the above-described refrigeration apparatus. For example, the turbomachine 1 can be used as turbocharger in a gas cycle (gas turbine or turbogas) or in a steam cycle (as turbopump).

For example in possible embodiments, the blading located in the transit volume 11 and the helical conduit 14 are part of separated circuits and the first working fluid and the second working fluid are different fluids which circulate in said separated circuits. The first working fluid can be used for rotating the turbine defined from the blading located in the transit volume 11 and thus actuating the compressor defined by the helical channel 14 and compressing the second working fluid. Depending on the specific application, the shaft of the turbomachine 1 according to the invention can be connected to an electric motor, as above shown, or to a generator or to a motogenerator. The turbomachine 1 according to the invention can furthermore be used with fluids of different types, for example viscous fluids (i.e. with dynamic viscosity higher than 10’ ¹ Pa s), Newtonian or nonNewtonian fluids, in hydroelectricity, with gas or steam or liquids.

Figure 17 shows another variant of the rotor 4 provided with three inlet series 15. The rotor has three circumferential surfaces with different diameters and axially side by side. Each series is positioned on one of the three circumferential surfaces. The inlets 15 of each series are connected to a respective helical conduit 14. The distributor 20, not shown in figure 17, is structured and configured for inserting the second working fluid through the inlets of one, two or of all the three series as a function of the flow rate. The turbomachine 1 is then adapted to work with variable loads.

Figures 18, 19 and 20 show variants wherein the rotor 4 is formed by a first part 47 carrying the blading and by a second part 48. The first part 47 and the second part 48 are separated elements and connected to each other, for example through screws and/or welds and/or Hirth teeth.

In figure 18, the second part 48 is the shaft 17 and the first part 47 is fitted on the second part 48. Furthermore, the helical conduit 14 is entirely fashioned in the first part 47 and around the shaft 17. The rotor 4 of figure 19 differs by the one of figure 18 because the helical conduit 14 is partly fashioned in the first part 47 and partly in the shaft 17. The inlets 15 are on the first part 47 and the outlet 16 is on the end of the shaft 17. In not shown embodiments, a single shaft 17 can carry multiple first parts 47 so as to realize a plurality of turbomachines 1. For example, the helical conduits 14 of the turbomachines 1 are connected to each other in series or in parallel and/or the transit volumes 11 of the turbomachines 1 are connected to each other in series or in parallel.

The second part 48 of the rotor 4 of figure 20 (turbopump) comprises a portion with greater diameter on which are disposed the outlets 16 and from which extends overhanging the shaft 17. The helical conduit 14 is entirely fashioned in the second part 48 and defines a pump. The inlet 15 is placed on the end of the shaft 17. The first part 47 carries the vanes 10 defining a turbine and has a central passage which houses the shaft 17 of the second part 48. The first part 47 is leaning against the portion with greater diameter and to it connected through a Hirth tooth 50 (toothed ring obtained on the first part 47 and toothed ring obtained on the portion with greater diameter). A plate 51 with toothed ring is furthermore screwed on the end of the shaft 17. The plate 51 engages with a toothed ring fashioned on the first part 47 (another Hirth tooth 50) and closes the first part between the portion with greater diameter and said plate 51 .

In a variant embodiment, not shown, the outlets 16, instead of on the peripheral edge of the portion with greater diameter, are placed on a side of said portion with greater diameter opposite the side from which extends overhanging the shaft 17. The outlets 16 of the pump defined by the helical conduit 14 are axial but can also be axial/radial. In this way, it is possible to better separate the flow of the first working fluid from flows of the second working fluid if they are at very different temperatures.

In other variants, not shown, the first part 47 is as the one of figure 20, the second part 48 is similar to the one of figure 20 but does not comprise the shaft 17 and in its turn the second part 48 is fitted on a shaft.

Figures 21 and 22 show examples of lightened rotors 4, i.e. wherein are fashioned empty portions 49. The rotor 4 of figure 21 is similar to the one of figures 1 and 3 but it has furthermore been fashioned a recess 49 in the portion not occupied by the helical conduit 14.

The rotor 4 of figure 22 is double (the helical conduit 14 is present but is not shown), as the ones of figures 11 and 12, and each blading is as the one of the rotor 4 shown in figures 1 and 3. A central portion of the rotor 4 has in section a rhomboid shape and the central inner portion is empty.

Figure 23 shows a rotor 4 similar to the one of figure 12 (two turbomachines 1 with vanes 10). Differently from figure 12, the helical conduit 14 is only one and has an inlet 15 located between vanes 10 of subsequent stages of a first turbomachine 1 and an outlet 16 located between vanes 10 of subsequent stages of a second turbomachine 1 . Figure 24 shows an enlargement of the outlet 16 and shows the speeds of the first fluid in proximity of a radially outer surface of the rotor 4. Figure 25 shows an enlargement of the inlet 15 and shows the speeds of the first fluid in proximity of the radially outer surface of the rotor 4. In this case, the first fluid and the second fluid are the same fluid and, as it can be noted, the extraction or the insertion of the fluid to the base of the vanes 10 energizes or draws the boundary layer so as to limit the formation of vortexes and increase the performance of the turbomachine 1.

Figure 26 shows a rotor 4 with only one blading, wherein the helical conduit 14 has an axial inlet 15 and an outlet 16 placed between vanes 10 of subsequent stages. In this case, the second fluid which passes in the helical conduit 14 is used for energizing the boundary layer of the first fluid. For example, the first fluid is a natural gas and the second fluid is hydrogen.

List of elements turbomachine 1 case 2 central portion 3 of the case rotor 4 sleeve 5 tubular body 6 cylindrical base 7 distal portion 8 radially outer surface 9 vanes 10 transit volume 11 inlet 12 transit volume outlet 13 transit volume helical conduit 14 inlets 15 helical conduit outlet 16 helical conduit shaft 17 bearings 18 diffuser 19 distributor 20 loop 21 septum 22 fixed blades 23 directional blades 24 radial supports 25 internal tubular body 26 first outlet 27 first inlet 28 second inlet 29 second outlet 30 rear wall 31 refrigeration apparatus 32 evaporator 33 condenser 34 electric motor 35 inlet 36 condenser outlet 37 condenser inlet 38 evaporator outlet 39 evaporator end 40 shaft body 41 radial supports 42 passage 43 for atmospheric air statoric vanes 44 sectors 45 auxiliary loop 46 first part 47 second part 48 empty portion 49

Hirth tooth 50 plate 51