Centrifugal radial turbine with parallel flows

Abstract

A centrifugal radial turbine with parallel flows comprises a case (2), a single rigid shaft (6) mounted in the case (2) and having a first end and a second end supported in the case (2), a rotor disk (9; 9A, 9B) mounted solidly on the single rigid shaft (6). First rotor vanes (13) are arranged on a first face (11) of the rotor disk (9; 9A, 9B) and in a first volume delimited in the case (2) and second rotor vanes (14) are arranged on a second face (12) of the rotor disk (9; 9A, 9B) and in a second volume delimited in the case (2). A working fluid entering through an inlet duct (39) or through a first inlet duct (25) and a second inlet duct (26) flows according to parallel flows through the first volume and the second volume and exits through an outlet duct (28) or through a first outlet duct (28A) and a second outlet duct (28B).

Description

[0001] DESCRIPTION

[0002] “Centrifugal radial turbine with parallel flows”

[0003] Field of the finding

[0004] The present invention has as its object a centrifugal radial turbine with parallel flows. As centrifugal radial turbine (in English “radial outflow turbine”) is intended a driving turbomachine wherein the fluid flow with which it exchanges energy is mainly directed in a radial direction with respect to the axis of rotation of the turbine and from the center toward the periphery of the turbine.

[0005] Preferably but not exclusively, the present invention refers to radial expansion turbines used in apparatuses for energy production by means of the water-steam Rankine cycle or organic Rankine cycle (ORC).

[0006] The present invention specifically refers to a double centrifugal radial turbine with parallel flows integrated into a single casing.

[0007] Background of the finding

[0008] The public document WO2018007909A1 shows an assembly of turbines comprising a first turbine provided with a first shaft and with a first rotor, a second turbine provided with a second shaft and with a second rotor and a flexible joint connected to a first front face of the first rotor and to a second front face of the second rotor to transmit the rotation of the first shaft to the second shaft or vice versa.

[0009] The document US5071312A shows a plurality of rotor disks and stator disks attached to a fixed shaft. The rotor disks are mounted on the shaft so that they can rotate with respect to the shaft and are constrained to each other to rotate all together with respect to that shaft.

[0010] The document WO2019123243A1 shows a turbine provided with a single rotor disk carried at the end of a shaft and supported cantilevered by a group of bearings.

[0011] The patent document FR525845A describes a radial turbine with two rotor discs and corresponding stators mounted on a shaft housed in a casing that has two opposite inlets and a common exhaust duct for the fluid discharged from both discs. The Applicant has noted that the centrifugal radial turbines of the above shown type are improvable under several aspects, particularly in relation to their compactness, constructive simplicity, robustness and stress resistance.

[0012] The Applicant has noted that the turbine shown in WO2018007909A1 is not actually a single turbine with parallel flows, but rather the coupling, via the elastic joint, of two separate and distinct turbines working with separate roto-dynamics.

[0013] The Applicant has noted that the turbine shown in US5071312A is structurally very complex and with difficult balancing, since all the rotors are carried by a rotating casing.

[0014] The Applicant has noted that the turbine shown in WO2019123243A1 may be subject to high vibrations as the rotor disk is supported cantilevered.

[0015] The Applicant has then perceived the need for realizing a centrifugal radial turbine with parallel flows that allows to overcome the drawbacks of the above-mentioned known turbines.

[0016] The Applicant has perceived the need for realizing a centrifugal radial turbine with parallel flows that allows also to:

[0017] - dispose of large volumetric flow rates by avoiding the use of turbines in parallel;

[0018] - reduce plant elements, such as piping and instruments, with respect to turbines in parallel;

[0019] - simplify the plant layout;

[0020] - reduce the realization and installation costs with respect to turbines in parallel;

[0021] - reduce the vibrations;

[0022] - change the support elements (bearings) and / or carry out maintenance of support elements without emptying the plant;

[0023] - eventually eliminate possible thrust compensation systems.

[0024] The Applicant has found that the above-mentioned objectives and others can be achieved by a centrifugal radial turbine with parallel flows that comprises a case, a single rigid shaft mounted in the case and having a first end and a second end supported in the case, at least one rotor disk solidly mounted on the single rigid shaft. First rotor vanes are arranged on a first face of the rotor disk and in a first volume delimited in the case and second rotor vanes are arranged on a second face of the rotor disk and in a second volume delimited in the case. A working fluid entering through an inlet duct or through a first inlet duct and a second inlet duct flows according to parallel flows through the first volume and the second volume and exits through an outlet duct or through a first outlet duct and a second outlet duct.

[0025] The Applicant has in particular found that the above-mentioned objectives and others can be achieved by a centrifugal radial turbine with parallel flows according to the attached claims and / or the following aspects.

[0026] More specifically, according to a 1stindependent aspect, the present invention refers to a centrifugal radial turbine with parallel flows, comprising: a case; a single rigid shaft mounted in the case and having a first end and a second end, opposite the first end, supported in the case so that the single rigid shaft can rotate around an its own main axis; at least one rotor disk solidly mounted on the single rigid shaft, coaxial to the main axis and comprising at least one array of first rotor vanes arranged on a first face of said at least one rotor disk and around the main axis, wherein leading edges of the first rotor vanes face the main axis, and at least one array of second rotor vanes arranged on a second face of said at least one rotor disk and around the main axis, wherein leading edges of the second rotor vanes face the main axis; wherein the case delimits a first volume housing said first rotor vanes and having a first inlet located at the single rigid shaft and a first outlet radially peripheral; wherein the case delimits a second volume housing said second rotor vanes and having a second inlet located at the single rigid shaft and a second outlet radially peripheral. The case comprises: an inlet duct in fluid communication with the first inlet and with the second inlet or a first inlet duct in fluid communication with the first inlet and a second inlet duct in fluid communication with the second inlet, so that a working fluid entering through the inlet duct or through the first inlet duct and the second inlet duct flows according to parallel flows through the first volume and the second volume and exits through the first outlet and the second outlet; an outlet duct in fluid communication with the first outlet and with the second outlet or a first outlet duct in fluid communication with the first outlet and a second outlet duct in fluid communication with the second outlet.

[0027] The Applicant has first verified that the turbine according to the invention allows to dispose of large volumetric flow rates while resulting very compact and robust. The compactness has a positive effect on the simplification of the plant layout. The Applicant has also verified that the turbine according to the invention allows to contain the vibrations with respect to the turbines with cantilevered (over-hung) disk because the shaft is single and supported at both its own ends.

[0028] The Applicant has also verified that the turbine according to the invention results structurally simple and relatively low-cost to produce.

[0029] Further aspects of the invention are described below.

[0030] In a 2ndaspect according to the 1staspect, the single rigid shaft is made in one piece. In a 3rdaspect according to one of the preceding aspects, the case comprises: a first stator placed in front of the first face and a second stator placed in front of the second face.

[0031] In a 4thaspect according to the preceding aspect, the first stator comprises at least one array of first stator vanes arranged in the first volume, around the main axis and in a radially inner position with respect to said at least one array of first rotor vanes; the second stator comprises at least one array of second stator vanes arranged in the second volume, around the main axis and in a radially inner position with respect to said at least one array of second rotor vanes.

[0032] In a 5thaspect according to one of the preceding aspects, said at least one rotor disk is a single rotor disk and the first face and the second face are opposite faces of the single rotor disk.

[0033] In a 6thaspect according to the preceding aspect, the first stator and the second stator are placed on axially opposite sides of the single rotor disk.

[0034] In a 7thaspect according to one of the aspects 1 to 4, said at least one rotor disk comprises a first rotor disk having the first face and comprising said at least one array of first rotor vanes and a second rotor disk having the second face and comprising said at least one array of second rotor vanes.

[0035] In an 8thaspect according to the preceding aspect and to the aspect 4, the first face and the second face face each other and the first stator and the second stator are axially arranged between the first rotor disk and the second rotor disk.

[0036] In a 9thaspect according to the aspect 7 and to the aspect 4, the first face and the second face face opposite parts and the first stator and the second stator are placed on axially opposite sides of the first rotor disk and of the second rotor disk.

[0037] In a 10thaspect according to one of the aspects 7 to 9, the first rotor disk has first through openings obtained in radially inner positions with respect to said at least one array of first rotor vanes and the second rotor disk has second through openings obtained in radially inner positions with respect to said at least one array of second rotor vanes.

[0038] In a 11thaspect according to one of the aspects 7 to 10, a first axial stage comprises one array of first axial rotor vanes arranged on a radially peripheral edge of said first rotor disk.

[0039] In a 12thaspect according to the preceding aspect, the first axial stage comprises one array of first axial stator vanes flanked by the first axial rotor vanes and mounted on the case.

[0040] In a 13thaspect according to the aspect 11 or 12, a second axial stage comprises one array of second axial rotor vanes arranged on a radially peripheral edge of the second rotor disk.

[0041] In a 14thaspect according to the preceding aspect, the second axial stage comprises one array of second axial stator vanes flanked by the second axial rotor vanes and mounted on the case.

[0042] In a 15thaspect according to one of the preceding aspects, said at least one array of first rotor vanes and said at least one array of second rotor vanes are symmetrical with respect to a plane of symmetry orthogonal to the main axis.

[0043] In a 16thaspect according to one of the preceding aspects, the case is symmetrical with respect to a plane of symmetry orthogonal to the main axis and / or the first and the second rotor disk are symmetrical with respect to the plane of symmetry orthogonal to the main axis.

[0044] In a 17thaspect according to one of the preceding aspects, the centrifugal radial turbine is substantially symmetrical with respect to a plane of symmetry orthogonal to the main axis.

[0045] The Applicant has verified that in such a way it is possible to eliminate any thrust compensation systems since the “mirrored / twin” structures are self-balancing.

[0046] In an 18thaspect according to one of the preceding aspects, the case delimits a first annular inlet chamber developing around the main axis, flanking the first inlet and in fluid communication with the first inlet and a second annular inlet chamber developing around the main axis, flanked by the second inlet and in fluid communication with the second inlet.

[0047] In a 19thaspect according to the preceding aspect, the first annular inlet chamber is connected to the first inlet duct and the second annular inlet chamber is connected to the second inlet duct. In a 20thaspect according to the preceding aspect when the aspect 18 is according to the aspect 10, wherein the first annular inlet chamber is connected to the first inlet duct through the first through openings and the second annular inlet chamber is connected to the second inlet duct through the second through openings.

[0048] In a 21staspect according to the aspect 19 or 20, the case delimits an annular outlet chamber developing around the main axis, axially interposed between the first annular inlet chamber and the second annular inlet chamber and in fluid communication with the first outlet and the second outlet.

[0049] In a 22ndaspect according to the preceding aspect, the annular outlet chamber develops around the first volume and the second volume.

[0050] In a 23rdaspect according to the aspect 21 or 22, the annular outlet chamber is connected to the outlet duct.

[0051] In a 24thaspect according to one of the aspects 1 to 23, the case delimits an annular inlet chamber developing around the main axis and in fluid communication with the first inlet and with the second inlet.

[0052] In a 25thaspect according to the preceding aspect when is according to the aspect 10, wherein the annular inlet chamber is in fluid communication with the first inlet and with the second inlet through the first through openings and the second through openings.

[0053] In a 26thaspect according to the preceding aspect, the annular inlet chamber is connected to the inlet duct.

[0054] In a 27thaspect according to the aspect 24, 25 or 26, the case delimits a first annular outlet chamber developing around the main axis and in fluid communication with the first outlet and a second annular outlet chamber developing around the main axis and in fluid communication with the second outlet.

[0055] In a 28thaspect according to the preceding aspect, the first annular outlet chamber develops around the first volume and the second annular outlet chamber develops around the second volume.

[0056] In a 29thaspect according to the aspect 27 or 28, the first annular outlet chamber is connected to the first outlet duct and the second annular outlet chamber is connected to the second outlet duct.

[0057] In a 30thaspect according to one of the aspects 1 to 29, a first support assembly is mounted in the case and is operatively interposed between a first end of the single rigid shaft and the case, a second support assembly is mounted in the case and is operatively interposed between a second end of the single rigid shaft and the case. In a 31staspect according to the aspect 30, the first support assembly and the second support assembly are configured to allow a rotation of the single rigid shaft in said case.

[0058] In a 32ndaspect according to the aspect 30 or 31 , said at least one rotor disk is axially interposed between the first support assembly and the second support assembly.

[0059] In a 33rdaspect according to one of the aspects 30 to 32, the case comprises a central body of substantially cylindrical outline and coaxial to the main axis, a first sleeve integral to the central body, coaxial to the main axis and developing away from a first end face of the central body; a second sleeve integral to the central body, coaxial to the main axis and developing away from a second end face of the central body; wherein the first support assembly is housed in the first sleeve and the second support assembly is housed in the second sleeve.

[0060] In a 34thaspect according to the preceding aspect, the first sleeve has a first open end configured to allow the extraction of the first support assembly from said first sleeve and from the single rigid shaft; and / or the second sleeve has a second open end configured to allow the extraction of the second support assembly from said second sleeve and from the single rigid shaft.

[0061] In a 35thaspect according to the preceding aspect, a first removable cover closes the first end and a second removable cover closes the second end.

[0062] In a 36thaspect according to the preceding aspect, the first cover or the second cover has a central bore for the passage of the single rigid shaft and its connection to a generator.

[0063] In a 37thaspect according to the preceding aspect, the single rigid shaft has a first shoulder facing a first circular sealing element mounted in the case and a second shoulder facing a second circular sealing element mounted in the case.

[0064] In a 38thaspect according to the preceding aspect, a first sealing ring provided with the first circular sealing element is installed around the single rigid shaft in proximity of a first shoulder and a second sealing ring provided with the second circular sealing element is installed around the single rigid shaft in proximity of a second shoulder. In a 39thaspect according to the preceding aspect, a first actuator is operatively coupled to the first sealing ring for moving it between a rest position, wherein the first circular sealing element is spaced from the first shoulder, and an operative position, wherein the first circular sealing element leans against the first shoulder; a second actuator is operatively coupled to the second sealing ring for moving it between a rest position, wherein the second circular sealing element is spaced from the second shoulder, and an operative position, wherein the second circular sealing element leans against the second shoulder.

[0065] When the centrifugal radial turbine with parallel flows is not operative and the single rigid shaft does not rotate, the first and the second sealing ring are brought to their respective operative positions so as to isolate the first volume and the second volume from the outer environment and to be able to do maintenance on the first support assembly or on the second support assembly.

[0066] In a 40thaspect according to one of the preceding aspects, the single rigid shaft has an annular relief, wherein the single rigid shaft is inserted in a central bore of said at least one rotor disk and wherein said at least one rotor disk is attached to the annular relief, optionally through screws or bolts.

[0067] In a 41staspect, the present invention refers to an organic Rankine cycle plant (Organic Rankine Cycle - ORC) comprising a centrifugal radial turbine with parallel flows according to one or more of the preceding aspects.

[0068] In a 42ndaspect according to the preceding aspect, the organic Rankine cycle plant comprises: a condenser, a pump, an evaporator and said centrifugal radial turbine with parallel flows; wherein the condenser, the pump, the evaporator and the centrifugal radial turbine with parallel flows are connected by piping to define a closed circuit; wherein the single rigid shaft is mechanically coupled to an electric generator.

[0069] In a 43rdaspect according to the aspect 41 or 42, wherein the organic Rankine cycle plant is implemented in a geothermal plant or in a biomass plant or in a heat recovery system from industrial processes or from turbine engines or in a liquid natural gas (LNG) regasification plant or in a concentrating solar power plant (CSP).

[0070] Further features and advantages will appear more from the detailed description of preferred, but not exclusive, embodiments of a centrifugal radial turbine with parallel flows according to the present invention. Description of figures

[0071] This description will be set forth below with reference to the attached drawings, provided for illustrative purposes only and, therefore, not limiting, in which:

[0072] ■ Figure 1 shows a section according to an axial plane of a centrifugal radial turbine with parallel flows according to the present invention;

[0073] ■ Figure 1 A is an enlargement of a portion of the turbine of figure 1 ;

[0074] ■ Figures 2 - 5 show respective variants of the centrifugal radial turbine with parallel flows according to the present invention;

[0075] ■ Figure 6 shows schematically an organic Rankine cycle plant comprising the centrifugal radial turbine according to the invention.

[0076] Definitions

[0077] In the present description and in the attached claims, the terms “axial”, “radial” and “circumferential” all refer to the main axis and single rotation axis of the turbine.

[0078] In the present description and in the attached claims, as “centrifugal radial turbine” is intended a driving turbomachine wherein the fluid flow with which it exchanges energy is directed mainly in a radial direction with respect to the axis of rotation of the turbine and from the center to the periphery of the turbine.

[0079] Detailed description

[0080] With reference to the mentioned figures, with reference number 1 has been overall indicated a centrifugal radial turbine with parallel flows. The turbine 1 comprises a case 2 provided with a central body 3 of substantially cylindrical outline and coaxial to a main axis “X-X”. The case 2 comprises also a first sleeve 4 integral to the central body 2, coaxial to the main axis “X-X” and developing away from a first end face of the central body 2 and a second sleeve 5 integral to the central body 2, coaxial to the main axis “X-X” and developing away from a second end face of the central body 2. The case 2 is substantially symmetrical with respect to a plane of symmetry “P” orthogonal to the main axis “X-X”. In the example embodiment shown in figure 1 , the case 2 is formed by multiple portions bolted between them that will be described hereinafter.

[0081] The turbine 1 comprises a single rigid shaft 6 mounted in the case 2, made in one piece and having a first end and a second end, opposite the first end, supported in the case 2 so that the single rigid shaft 6 can rotate around the main axis “X-X”. In particular, a first support assembly 7 is mounted in the first sleeve 4 and is operatively interposed between a first end of the single rigid shaft 6 and said first sleeve 4. A second support assembly 8 is mounted in the second sleeve 5 and is operatively interposed between a second end of the single rigid shaft 6 and said second sleeve 5. The first and the second support assembly 7, 8 are shown only schematically in figure 1 , comprise radial bearings and seals and are configured to allow a rotation of the single rigid shaft in the case 2.

[0082] A rotor disk 9 is mounted solidly on the single rigid shaft 6. In particular, the single rigid shaft 6 comprises an annular relief 10, the rotor disk 9 has a central bore. The single rigid shaft 6 is inserted in the central bore of the rotor disk 9 and a portion next to the central bore is abutted against the annular relief 10 and attached to said annular relief 10 through screws or bolts. The rotor disk 9 is mounted about at half of the single rigid shaft 6 and is axially interposed between the first support assembly 7 and the second support assembly 8.

[0083] The rotor disk 9 has a first face 11 and a second face 12 opposite the first face 11 . On the first face 11 are installed six arrays of first rotor vanes. The first rotor vanes 13 of each array are arranged around the main axis “X-X”. The arrays of first rotor vanes 13 are concentric to each other. Leading edges of the first rotor vanes 13 face the main axis “X-X” to define the typical structure of a centrifugal radial turbine. Analogously, on the second face 12 are installed six arrays of second rotor vanes 14. The second rotor vanes 14 of each array are arranged around the main axis “X- X”. The arrays of second rotor vanes 14 are concentric to each other. Leading edges of the second rotor vanes 14 face the main axis “X-X”. The rotor disk 9, the arrays of first rotor vanes 13 and the arrays of second rotor vanes 14 are symmetrical with respect to the mentioned plane of symmetry “P”.

[0084] The rotor disk 9 is housed in a seat delimited internally by a first portion 2A of the case 2. A first stator is housed too in said seat and is placed in front of the first face 11 . The first stator comprises six arrays of first stator vanes 15 concentric to each other and arranged in an alternating way, along radial directions, with respect to the arrays of first rotor vanes 13. A second stator is housed in the seat and is placed in front of the second face 12. The second stator comprises six arrays of second stator vanes 16 concentric to each other and arranged in an alternating way, along radial directions, with respect to the arrays of second rotor vanes 14. The first stator and the second stator are located on axially opposite sides of the single rotor disk 9. The seat and the rotor disk 9 delimit a first volume that houses the first rotor vanes 13 and the first stator vanes 15 and extends between a first inlet 17 located at the single rigid shaft 6 and a first outlet 18 radially peripheral. As it can be seen, the first inlet 17 allows the inlet of a working fluid along directions substantially parallel to the main axis “X-X” (axial inlet) and the shape of the inlet together with the first stator vanes 15 housed therein address the fluid toward radial directions.

[0085] In an analogous way, the seat and the rotor disk 9 delimit a second volume that houses the second rotor vanes 14 and the second stator vanes 16 and extends between a second inlet 19 located at the single rigid shaft 6 and a second outlet 20 radially peripheral. As it can be seen, the second inlet 19 allows the inlet of a working fluid along directions substantially parallel to the main axis “X-X” (axial inlet) and the shape of the inlet together with the second stator vanes 16 housed therein address the fluid to radial directions.

[0086] The case 2 delimits a first annular inlet chamber 21 developing around the main axis “X-X” and a second annular inlet chamber 22 developing around the main axis “X- X”. The first annular inlet chamber 21 is flanked by the first inlet 17 and is connected to the first inlet 17 through a plurality of first oblique ducts 23 (figure 1A). The second annular inlet chamber 22 is flanked by the second inlet 19 and is connected to the second inlet 19 through a plurality of second oblique ducts 24 (figure 1A).

[0087] The case 2 of figure 1 comprises a first inlet duct 25 in fluid communication with the first annular inlet chamber 21 and then with the first inlet 17. The case 2 of figure 1 comprises a second inlet duct 26 in fluid communication with the second annular inlet chamber 22 and then with the second inlet 19.

[0088] The case 2 delimits an annular outlet chamber 27 that develops around the main axis “X-X”, is axially interposed between the first annular inlet chamber 21 and the second annular inlet chamber 22 and surrounds the first outlet 18 and the second outlet 20. The case 2 of figure 1 comprises an outlet duct 28 in fluid communication with the annular outlet chamber 27 and then with the first outlet 18 and the second outlet 20.

[0089] The annular outlet chamber 27 and the first and second outlet 18, 20 are obtained in a second annular portion 2B that is part of the case 2 and is joined to the first portion 2A through screws. The first annular inlet chamber 21 and the second annular inlet chamber 22 are delimited by respective third portions 2C of the case 2 and by outer surfaces of the first portion 2A and of the second annular portion 2B. These third portions 2C carry also the first and the second inlet duct 25, 26.

[0090] The working fluid that enters through the first inlet duct 25 and the second inlet duct 26 flows in the first annular inlet chamber 21 and in the second annular inlet chamber 22, through the first oblique ducts 23 and the second oblique ducts 24, flows then according to parallel flows through the first volume and the second volume and exits through the first outlet 18 and the second outlet 20, the annular outlet chamber 27 and the outlet duct 28.

[0091] The first sleeve 4 is bolted to the first portion 2A of the case 2 and has a first open and resealable end through a first removable cover 29. The first open end is configured to allow the extraction of the first support assembly 7 from the first sleeve 4 and from the single rigid shaft 6 to carry out maintenance operations.

[0092] The second sleeve 5 is bolted to the first portion 2A of the case 2 and has a second open and resealable end through a second removable cover 30. The second removable cover 30 is provided with a central bore 31 and the single rigid shaft 6 exits through said central bore 31 to allow its connection to a generator, not shown. The second open end is configured to allow the extraction of the second support assembly 8 from said second sleeve 5 and from the single rigid shaft 6 to carry out maintenance operations.

[0093] A first sealing ring 32 provided with a respective first circular sealing element 33 (for example an O-ring) is installed around the single rigid shaft 6 in proximity of a first shoulder 34 of the single rigid shaft 6. The first sealing ring 32 is axially arranged between the first support assembly 4 and the first volume. The first shoulder 34 faces the first circular sealing element 33.

[0094] A second sealing ring 35 provided with a respective second circular sealing element 36 (for example an or-ring) is installed around the single rigid shaft 6 in proximity of a second shoulder 37 of the single rigid shaft 6. The second sealing ring 35 is axially arranged between the second support assembly 4 and the second volume. The second shoulder 37 faces the second circular sealing element 36.

[0095] A first actuator is operatively coupled to the first sealing ring 32 to move it between a rest position, wherein the first circular sealing element 33 is spaced from the first shoulder 34 (as in figures 1 and 1 A), and an operative position, not shown, wherein the first circular sealing element 33 leans against the first shoulder 34. Analogously, a second actuator is operatively coupled to the second sealing ring 35 to move it between a rest position (as in figures 1 and 1 A), wherein the second circular sealing element 36 is spaced from the second shoulder 37, and an operative position, not shown, wherein the second circular sealing element 36 leans against the second shoulder 37.

[0096] The first actuator and the second actuator, not shown, can for example be of mechanical, electromechanical and / or pneumatic type.

[0097] The embodiment of figure 2 differs from the one of figures 1 and 1A since it comprises a first rotor disk 9A and a second rotor disk 9B. The first rotor disk 9A has the first face 11 with the arrays of first rotor vanes 13. The second rotor disk 9B has the second face 12 with the arrays of second rotor vanes 14. The first face 11 and the second face 12 face each other and are separated by an annular inlet chamber 38 that develops around the main axis “X-X” and is in fluid communication with the first inlet 17 and with the second inlet 19 in proximity of the single rigid shaft 6 and with a single inlet duct 39. The first stator is axially arranged between the first rotor disk 9A and the annular inlet chamber 38. The second stator is axially arranged between the second rotor disk 9B and the annular inlet chamber 38. The first and the second rotor disk 9A, 9B are symmetrical with respect to the plane of symmetry “P”. The centrifugal radial turbine 1 as a whole is substantially symmetrical with respect to the above-mentioned plane of symmetry “P”.

[0098] The case 2 delimits a first annular outlet chamber 27A that develops around the main axis “X-X” and around the first volume and is in fluid communication with the first outlet 18 and with a first outlet duct 28A. The case 2 delimits a second annular outlet chamber 27B that develops around the main axis “X-X” and around the second volume and is in fluid communication with the second outlet 20 and with a second outlet duct 28B. The first annular outlet chamber 27A and the second annular outlet chamber 27B are located on the opposite sides of the annular inlet chamber 38.

[0099] Unlike figures 1 and 1A, the single rigid shaft 6 exits from the first removable cover 29.

[0100] The embodiment of figure 3 differs from the one of figures 1 and 1A since it comprises a first rotor disk 9A and a second rotor disk 9B with the first face 11 and the second face 12 facing each other, as the embodiment of figure 2. Unlike the embodiment of figure 2, the first and the second annular outlet chamber 27A, 27B are juxtaposed and interposed between the first rotor disk 9A and the second rotor disk 9B. Furthermore, the first annular inlet chamber 21 and the second annular inlet chamber 22 are located on opposite sides of said first and second annular outlet chamber 27A, 27B.

[0101] The first annular inlet chamber 21 is on the side of the first rotor disk 9A opposite with respect to the first face 11 and to the first volume and, likewise, the second annular inlet chamber 22 is on the side of the second rotor disk 9B opposite with respect to the second face 12 and to the second volume.

[0102] The first rotor disk 9A has first through openings 40A obtained in radially inner positions with respect to the first rotor vanes 13 which connect the first annular inlet chamber 21 with the first inlet 17. The second rotor disk 9B has second through openings 40B obtained in radially inner positions with respect to the second rotor vanes 14 which connect the second annular inlet chamber 22 with the second inlet 19.

[0103] The embodiment of figure 4 differs from the one of figure 2 since the first face 11 of the first rotor disk 9A and the second face 12 of the second rotor disk 9B face opposite sides. The first stator and the second stator are located on axially opposite sides of the first rotor disk 9A and of the second rotor disk 9B. The annular inlet chamber 38 is connected to the first inlet 17 and to the second inlet 19 through first through openings 40A obtained in the first rotor disk 9A and second through openings 40B obtained in the second rotor disk 9B.

[0104] The embodiment of figure 5 differs from the one of figure 2 since it is furthermore present a first axial stage comprising one array of first axial rotor vanes 41 A arranged on a radially peripheral edge of the first rotor disk 9A and one array of first axial stator vanes 42A flanked by the first axial rotor vanes 41 A and mounted on the case 2. Analogously, is furthermore present a second axial stage comprising one array of second axial rotor vanes 41 B arranged on a radially peripheral edge of the second rotor disk 9B and one array of second axial stator vanes 42B flanked by the second axial rotor vanes 41 B and mounted on the case 2.

[0105] The centrifugal radial turbine with parallel flows 1 according to one of the abovedescribed embodiments can be used in an organic Rankine cycle plant 100 (Organic Rankine Cycle - ORC) as the one schematically shown in figure 6. The organic Rankine cycle plant 100 shown comprises: a high-pressure condenser 101 , a low- pressure condenser 102, a pump 103, an evaporator 104 and said centrifugal radial turbine with parallel flows 1. The high-pressure condenser 101 , the low-pressure condenser 102, the pump 103, the evaporator 104 and the centrifugal radial turbine with parallel flows 1 are connected in series by pipelines configured to define a closed circuit. The single rigid shaft 6 of the centrifugal radial turbine with parallel flows 1 is mechanically coupled to an electric generator 105. This organic Rankine cycle plant can for example be implemented in a geothermal plant or in a biomass plant or in a system for heat recovery from industrial processes or from turbine engines or in a liquid natural gas (LNG) regasification plant or in a concentrating solar power plant (CSP).

[0106] List of elements

[0107] 1 centrifugal radial turbine with parallel flows

[0108] 2 case

[0109] 2A first portion

[0110] 2B second annular portion

[0111] 2C third portions

[0112] 3 central body

[0113] 4 first sleeve

[0114] 5 second sleeve

[0115] 6 single rigid shaft

[0116] 7 first support assembly

[0117] 8 second support assembly

[0118] 9 rotor disk

[0119] 10 annular relief

[0120] 11 first face

[0121] 12 second face

[0122] 13 first rotor vanes

[0123] 14 second rotor vanes

[0124] 15 first stator vanes

[0125] 16 second stator vanes

[0126] 17 first inlet

[0127] 18 first outlet

[0128] 19 second inlet

[0129] 20 second outlet

[0130] 21 first annular inlet chamber 22 second annular inlet chamber

[0131] 23 first oblique ducts

[0132] 24 second oblique ducts

[0133] 25 first inlet duct

[0134] 26 second inlet duct

[0135] 27 annular outlet chamber

[0136] 28 outlet duct

[0137] 28A first outlet duct

[0138] 28B second outlet duct

[0139] 29 first removable cover

[0140] 30 second removable cover

[0141] 31 central bore

[0142] 32 first sealing ring

[0143] 33 first circular sealing element

[0144] 34 first shoulder

[0145] 35 second sealing ring

[0146] 36 second circular sealing element

[0147] 37 second shoulder

[0148] 38 annular inlet chamber

[0149] 39 inlet duct

[0150] 40A first through openings

[0151] 40B second through openings

[0152] 41 A first axial rotor vanes

[0153] 41 B first axial stator vanes

[0154] 42A second axial rotor vanes

[0155] 42B second axial stator vanes

[0156] 100 organic Rankine cycle plant

[0157] 101 high pressure condenser

[0158] 102 low pressure condenser

[0159] 103 pump

[0160] 104 evaporator

[0161] 105 electric generator

[0162] X-X main axis

[0163] P plane of symmetry

Claims

CLAIMS1 . Centrifugal radial turbine with parallel flows, comprising:- a case (2);- a single rigid shaft (6) mounted in the case (2) and having a first end and a second end, opposite the first end, supported in the case (2) so that the single rigid shaft (6) can rotate around its own main axis (X-X);- a rotor disk (9) solidly mounted on the single rigid shaft (6), coaxial to the main axis (X-X) and comprising at least one array of first rotor vanes (13) arranged on a first face (11 ) of said rotor disk (9) and around the main axis (X-X), wherein leading edges of the first rotor vanes (13) face the main axis (X-X), and at least one array of second rotor vanes (14) arranged on a second face (12) of said rotor disk (9) and around the main axis (X-X), wherein leading edges of the second rotor vanes (14) face the main axis (X-X); wherein the case (2) delimits a first volume housing said first rotor vanes (13) and presenting a first inlet (17) located at the single rigid shaft (6) and a first outlet (18) radially peripheral; wherein the case (2) delimits a second volume housing said second rotor vanes (14) and presenting a second inlet (19) placed at the single rigid shaft (6) and a second outlet (20) radially peripheral; wherein the case (2) comprises: an inlet duct (39) in fluid communication with the first inlet (17) and the second inlet (19) or a first inlet duct (25) in fluid communication with the first inlet (17) and a second inlet duct (26) in fluid communication with the second inlet (19), so that a working fluid entering through the inlet duct (39) or through the first inlet duct (25) and the second inlet duct (26) flows according to parallel flows through the first volume and the second volume and exits through the first outlet (18) and the second outlet (20); an outlet duct (28) in fluid communication with the first outlet (18) and the second outlet (20) or a first outlet duct (28A) in fluid communication with the first outlet (18) and a second outlet duct (28B) in fluid communication with the second outlet (20);a first stator arranged in front of the first face (11 ) and a second stator arranged in front of the second face (12); wherein said rotor disk is a single rotor disk (9) and wherein the first face (11 ) and the second face (12) are opposite faces of the single rotor disk (9); wherein the first stator and the second stator are positioned on axially opposite sides of the single rotor disk (9).

2. Turbine according to claim 1 , wherein the single rigid shaft (6) is made in one piece.

3. Turbine according to claim 1 or 2, said centrifugal radial turbine (1 ) is symmetrical with respect to a plane of symmetry (P) orthogonal to the main axis (X- X).

4. Turbine according to claim 1 or 2 or 3, wherein the single rigid shaft (6) has an annular projection (10), wherein the single rigid shaft (6) is inserted into a central hole of said rotor disk (9), and wherein said rotor disk (9) is fixed to the annular projection (10).

5. Turbine according to one of claims 1 to 4, wherein said at least one array of first rotor vanes (13) and said at least one array of second rotor vanes (14) are symmetrical with respect to a plane of symmetry (P) orthogonal to the main axis (X- X) and wherein the case (2) is symmetrical with respect to said plane of symmetry (P).

6. Turbine according to any one of claims 1 to 5, wherein the case (2) bounds a first annular inlet chamber (21 ) developed around the main axis (X-X), flanking the first inlet duct (17) and in fluid communication with the first inlet duct (17) and a second annular inlet chamber (22) developed around the main axis (X-X), flanking the second inlet duct (19) and in fluid communication with the second inlet duct (19); wherein the first annular inlet chamber (21 ) is connected to the first inlet duct (25) and the second annular inlet chamber (22) is connected to the second inlet duct7. Turbine according to claim 6, wherein the case (2) delimits an annular outlet chamber (27) developing around the main axis (X-X), axially interposed between the first annular inlet chamber (21 ) and the second annular inlet chamber (22) and in fluid communication with the first outlet (18) and the second outlet (20); wherein the annular outlet chamber (27) develops around the first volume and the second volume; wherein the annular outlet chamber (27) is connected to the outlet duct (28).

8. Turbine according to any of claims 1 to 7, comprising: a first support assembly (7) mounted in the case (2) and operatively interposed between the first end of the single rigid shaft (6) and the case (2); a second support assembly (8) mounted in the case (2) and operatively interposed between the second end of the single rigid shaft (6) and the case (2); the first support assembly (7) and the second support assembly (8) being configured to allow a rotation of the single rigid shaft (6) in said case (2); wherein said rotor disk (9) is axially interposed between the first support assembly (7) and the second support assembly (8).

9. Turbine according to claim 8, wherein the case (2) comprises a central body(3) of substantially cylindrical outline and coaxial to the main axis (X-X), a first sleeve(4) integral with the central body (3), coaxial to the main axis (X-X) and developing away from a first end face of the central body (3); a second sleeve (5) integral to the central body (3), coaxial to the main axis (X-X) and developing away from a second end face of the central body (3); wherein the first support assembly (4) is housed in the first sleeve (7) and the second support assembly (8) is housed in the second sleeve (5).

10. Turbine according to claim 9, wherein the first sleeve (4) has a first open end configured to allow the removal of the first support assembly (7) from said first sleeve (4) and from the single rigid shaft (6); and the second sleeve (5) has a second open end configured to allow the removal of the second support assembly (8) from said second sleeve (5) and from the single rigid shaft (6).

11. Turbine according to claim 10, comprising a first removable cover (29) that closes the first end, and a second removable cover (30) that closes the second end.

12. Turbine according to claim 11 , wherein the first removable cover (29) or the second removable cover (30) has a central hole (31 ) for the passage of the single rigid shaft (6) and its connection to a generator.

13. T urbine according to any one of the claims 1 to 12, wherein the single rigid shaft (6) has a first shoulder (34) facing a first circular sealing element (33) mounted in the casing (2), and a second shoulder (37) facing a second circular sealing element (36) mounted in the casing (2); wherein a first sealing ring (32) provided with the first circular sealing element (33) is installed around the single rigid shaft (6) in proximity to the first shoulder (34), and a second sealing ring (35) provided with the second circular sealing element (36) is installed around the single rigid shaft (6) in proximity to the second shoulder (37).

14. Turbine according to claim 13, wherein a first actuator is operatively coupled to the first sealing ring (32) to move it between a rest position, in which the first circular sealing element (33) is spaced apart from the first shoulder (34), and an operative position, in which the first circular sealing element (33) rests against the first shoulder (34); wherein a second actuator is operatively coupled to the second sealing ring (35) to move it between a rest position, in which the second circular sealing element (36) is spaced apart from the second shoulder (37), and an operative position, in which the second circular sealing element (36) rests against the second shoulder (37).

15. Organic Rankine cycle plant, comprising: a condenser (101 , 102), a pump (103), an evaporator (104), and a centrifugal radial turbine with parallel flows (1 ) according to at least one preceding claims; wherein the condenser (101 , 102), the pump (103), the evaporator (104), and the centrifugal radial turbine with parallel flows (1 ) are connected by piping to define a closed circuit; wherein the single rigid shaft (6) is mechanically coupled to an electric generator (105).

Images