Geared turbomachinery system having at least three impellers with non-parallel rotation axes

Abstract

Integrally geared turbomachinery system (200) comprising a wheel gear (90) configured to rotate around a rotating axis (R) and at least a couple of pinion shafts (10, 20) mechanically coupled to the wheel gear (90). A first pinion shaft (10) is configured to be mechanically coupled to the wheel gear (90) and to rotate around a first axis (X) parallel to the rotating axis (R) at a first rotating speed and a second pinion shaft (20) is configured to be mechanically coupled to the first pinion shaft (10) and to rotate around a second axis (Y) at a second rotating speed; the first axis (X) and the second axis (Y) are non-parallel.

Description

TITLEGEARED TURBOMACHINERY SYSTEM HAVING AT LEAST THREE IMPELLERS WITH NON-PARALLEL ROTATION AXESDESCRIPTIONTECHNICAL FIELD

[0001] The subject-matter disclosed herein relates to an integrally geared turbomachinery system having at least three impellers with non-parallel rotation axes.BACKGROUND ART

[0002] Known integrally geared turbomachinery systems consist of a central low-speed wheel (known as “bull gear”) and multiple pinion gears on the outside of it driving a plurality of high-speed shafts, in particular pinion shafts. Typically, standard integrally geared turbomachinery systems have a plurality of pinion shafts, each pinion shaft driving one or two overhung impellers (i.e. two impellers located at the opposite ends of the shaft). It is important to note that each pinion shaft has a rotation axis which is parallel to the rotation axis of the bull gear.

[0003] Currently, increasing the number of impellers of the system, which results in increasing the number of high-speed shafts, leads to increase the vertical footprint of the system. In fact, not only the impellers have a certain spatial footprint, but also each impeller may require one of more of: volute, inlet guide vane unit and vaned or vaneless diffuser. Therefore, in order to ensure the proper space for each impeller, the pinion shafts are coupled to the low-speed wheel at different angular positions, hence increasing the vertical footprint of the machine. For example, if a four-shaft system is provided and a0° angular reference of the low-speed wheel is settled at the upper point of the intersection of a vertical plane with the wheel, a first high-speed shaft would be typically coupled to the low-speed wheel at a 90° angular position, a second high-speed shaft would be typically coupled at a -90° angular position, a third high-speed shaft would be typically coupled at a 30° angular position and a fourth high-speed shaft would be typically coupled at a -30° angular position.

[0004] However, from the point of view of transportability, the vertical dimension of the system is the most critical. In fact, generally the system is transported by wheel and is subjected to road dimensions and infrastructures dimensions (in particular the height of bridges).

[0005] Therefore, it would be desirable to have a multi-shaft integrally geared turbomachinery system with lower vertical footprint.SUMMARY

[0006] According to an aspect, the subject-matter disclosed herein relates to an integrally geared turbomachinery system which comprises a wheel gear, configured to rotate around a rotating axis, and a couple of pinion shafts mechanically coupled to the wheel gear. A first pinion shaft is configured to be mechanically coupled to the wheel gear and to rotate at a first rotating speed around a first axis parallel to the rotating axis, while a second pinion shaft is configured to be mechanically coupled to the first pinion shaft and to rotate at a second rotating speed around a second axis, the first axis and the second axis being non-parallel.BRIEF DESCRIPTION OF THE DRAWINGS

[0007] A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the followingdetailed description when considered in connection with the accompanying drawings, wherein:Fig. 1 shows a longitudinal view of a (partial) schematic diagram of an integrally geared turbomachinery system of the prior art,Fig. 2 shows an axial view of a schematic diagram of an integrally geared turbomachinery system of the prior art enclosed in a casing,Fig. 3 shows a longitudinal view of a (partial) schematic diagram of an embodiment of an innovative integrally geared turbomachinery system, andFig. 4 shows an axial view of a schematic diagram of an innovative integrally geared turbomachinery system enclosed in a casing.DETAILED DESCRIPTION OF EMBODIMENTS

[0008] According to an aspect, the subject-matter disclosed herein relates to an integrally geared turbomachinery system comprising a wheel gear, which is configured to rotate around a rotating axis, and at least a couple of pinion shafts, which are mechanically coupled to the wheel gear. The first pinion shaft is configured to be mechanically coupled (in particular directly coupled) to the wheel gear and to rotate around a first axis parallel to the rotating axis at a first rotating speed, while the second pinion shaft is configured to be mechanically coupled to the first pinion shaft and to rotate around a second axis at a second rotating speed, the first axis and the second axis being non-parallel.

[0009] Reference now will be made in detail to embodiments of the disclosure, examples of which are illustrated in the drawings. The examples and drawing figures are provided by way of explanation of the disclosure and should not be construed as a limitation of the disclosure. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present disclosure without departing from the scope or spiritof the disclosure. In the following description, similar reference numerals are used for the illustration of figures of the embodiments to indicate elements performing the same or similar functions. Moreover, for clarity of illustration, some references may be not repeated in all the figures.

[0010] Referring now to the drawings, Fig. 1 is a longitudinal partial view (in particular a partial top-view) of a schematic diagram of a known integrally geared turbomachinery system 100 and Fig. 2 is an axial view of schematic diagram of a known integrally geared turbomachinery system enclosed in a casing; Fig. 3 is a longitudinal partial view (in particular a partial top-view) of a schematic diagram of an embodiment of an innovative integrally geared turbomachinery system and Fig. 4 is an axial view of schematic diagram of an embodiment of an innovative integrally geared turbomachinery system enclosed in a casing. For the sake of clarity, it is to be noted that Figures 1 and 3 show only a partial schematic diagram of a system: in fact, Figs. 1 and 3 are partial longitudinal views (i.e. longitudinal views of a half of the system) in which only the rotating parts of the system are shown.

[0011] The innovative integrally geared turbomachinery systems herein disclosed essentially differs from the prior-art integrally geared turbomachinery system 100 (see e.g. Fig. 1 and Fig. 3) in that the system has at least one pinion shaft which is mechanically coupled to the wheel gear and rotates around an axis which has a different direction with respect to the rotation axis of the wheel gear (i.e. the pinion shaft rotates around an axis which is non-parallel with respect to the rotation axis of the wheel gear). According to the innovative integrally geared turbomachinery systems herein disclosed, the system may have a smaller vertical development compared to known solutions and therefore may be enclosed in a smaller casing. Moreover, it is to be noted that the casing is typically vertically splitted along split line(s) which is at each axis of the pinion shafts (i.e. each split line of the casing is defined by anhorizontal plane which contains the axis of at least one pinion shaft). Thus, the disclosed solution allows further to reduce the number of split lines of the casing as advantageously the axis of more pinion shafts may lie on the same horizontal plane (see e.g. Fig. 2 and Fig. 4).

[0012] In Figure 3 there is shown, for example and without limitation, an embodiment of an innovative integrally geared turbomachinery system generally indicated with reference numeral 200. The system 200 comprises a wheel gear 90, configured to rotate around a rotating axis R, and a couple of pinion shafts 10 and 20, configured to be mechanically coupled to the wheel gear 90. As it will be apparent from the following, the pinion shafts 10 and 20 may be directly and / or indirectly coupled to the wheel gear 90; in particular, a first pinion shaft 10 is directly coupled to the wheel gear 90 while a second pinion shaft 20 is indirectly coupled to the wheel gear 90.

[0013] With non-limiting reference to Fig. 3, the wheel gear 90 may be driven by a drive shaft 80 which rotates around a rotation axis R or the wheel gear 90 may drive the drive shaft 80 in order to rotate around the rotation axis R. As already mentioned, the first pinion shaft 10 is configured to be mechanically coupled, in particular directly coupled, to the wheel gear 90 and to rotate around a first axis X (i.e. the rotation axis X of the first pinion shaft) at a first rotational speed; it is to be noted that the first axis X is parallel to the rotating axis R of the wheel gear 90. In particular, the first pinion shaft 10 has a pinion portion 11 which is configured to cooperate with the wheel gear 90, more in particular the pinion portion 11 engages a peripheral toothing of the wheel gear 90; in other words, the wheel gear 90 transmits a motion to the first pinion shaft 10.

[0014] As it will be better described in the following, the second pinion shaft 20 is configured to be mechanically coupled, in particular directly coupled, to the first pinion shaft 10 and to rotate around a second axis Y at a secondrotating speed. In other words, the mechanical coupling between the first pinion shaft 10 and the second pinion shaft 20 allows the transmission of a motion by the first pinion shaft 10 to the second pinion shaft 20. In particular, the second pinion shaft 20 is indirectly mechanically coupled to the wheel gear 90. It is to be noted that the first rotating speed of the first pinion shaft 10 and the second rotating speed of the second pinion shaft may be the same rotating speed or may be different rotating speeds, in particular depending on the means for performing the mechanical coupling.

[0015] According to the solution herein disclosed, the first axis X of the first pinion shaft 10 and the second axis Y of the second pinion shaft 20 are nonparallel. In particular, with non-limiting reference to Fig. 3, the first axis X and the second axis Y may be perpendicular (i.e. the first axis X and the second axis Y define an angle of 90°); however, according to other embodiments not shown in the figures, the first axis X and the second axis Y may define an angle less than 90° or greater than 90° (but less than 180°).

[0016] With non-limiting reference to Fig. 3, the system 200 further comprises a first bevel gear 51 mechanically coupled to the first pinion shaft and a second bevel gear 52 mechanically coupled to the second pinion shaft 20. Advantageously, the first bevel gear 51 and the second bevel gear 52 are mechanically coupled to each other so that the first bevel gear 51 is configured to transmit motion to the second bevel gear 52, more in particular to the second pinion shaft 20.

[0017] Advantageously, the first pinion shaft 10 comprises a first impeller 31 and a second impeller 32 which are respectively mechanically coupled at a first end and at a second end of the first pinion shaft 10. It is to be noted that the fist impeller 31 and the second impeller 32 may be a compressor and / or an expander configured to respectively compress a fluid flow and / or expand a fluid flow. Advantageously, the first impeller 31 and the second impeller 32are configured to rotate around the first axis X of the first pinion shaft 10 at the first rotating speed; even more advantageously, the first rotating speed is an optimal rotating speed of the first impeller 31 and / or the second impeller 32 (i.e. a rotating speed adapted to maximize the efficiency of the first impeller and / or the second impeller).

[0018] Advantageously, the second pinion shaft 20 comprises a third impeller 33 mechanically coupled at a first end of the second pinion shaft 20, in particular at the opposite end with respect to the second bevel gear 52. It is to be noted that the third impeller 33 may be a compressor or an expander configured to respectively compress a fluid flow or expand a fluid flow, as it will be better described in the following. Advantageously, the third impeller 33 is configured to rotate around the second axis Y of the second pinion shaft 20 at the second rotating speed; even more advantageously, the second rotating speed is an optimal rotating speed of the third impeller 33 (i.e. a rotating speed adapted to maximize the efficiency of the third impeller).

[0019] As already mentioned, the first impeller 31, the second impeller 32 and the third impeller 33 are configured to process a fluid flow, in particular to compress and / or expand a fluid flow; it is to be noted that the fluid flow processed by the first impeller 31, the fluid flow processed by the second impeller 32 and the fluid flow processed by the third impeller 33 may be the same fluid flow and / or different fluid flows. It is also to be noted that, for the purpose of the present disclosure, “different fluid flows” means fluids which may have different compositions and / or different mass flow, for example due to fluid extractions or fluid injections.

[0020] According but not limited to the embodiment shown in Fig. 3, the first impeller 31 and the second impeller 32 are equally spaced with respect to the third impeller 33. In other words, the second pinion shaft 20, in particular the second axis Y of the second pinion shaft 20, may be located at the middle ofthe first pinion shaft 10.

[0021] With non-limiting reference to Fig. 3, the system 200 further comprises at least one bearing 41, 42 and 43 for each pinion shaft 10 and 20, in particular mechanically coupled to the pinion shafts 10 and 20 and configured to axially support the pinion shafts 10 and 20. In particular, Fig. 3 shows two bearings 41 and 42 mechanically coupled to the first pinion shaft 10 and one bearing 43 mechanically coupled to the second pinion shaft 20; however, the number of the bearings for each pinion shaft may be different.

[0022] Advantageously, with non-limiting reference to Fig. 4, the system 200 further comprises a casing 210 configured to enclose the wheel gear 90 and the pinion shafts 10 and 20, more advantageously a plurality of pinion shafts 10 and 20. The casing 210 is further configured to allow the flowing of the fluid flows to and from the first impeller 31, the second impeller 32 and the third impeller 33.

[0023] As already mentioned, the system 100 may comprise a plurality of pinion shafts 10 and 20 having the first axis X of each first pinion shaft 10 at a different angular position with respect to the wheel gear 90. For example, Fig. 4 shows schematically a side section view of the system 200 enclosed in the casing 210 having a couple of pinion shafts 10 located respectively at -90° and +90°. It is to be noted that the system 200 may comprise a different number of first pinion shafts 10, for example four pinion shafts 10; advantageously, the angular positions of the first shafts 10 are located in an upper section of the system 200 with respect to the rotating axis R. According to a possibility, the angular positions of the first shafts 10 are equally spaced.

Claims

CLAIMS1. Integrally geared turbomachinery system (200) comprising a wheel gear (90) configured to rotate around a rotating axis (R) and at least a couple of pinion shafts (10, 20) mechanically coupled to the wheel gear (90), wherein a first pinion shaft (10) is configured to be mechanically coupled to the wheel gear (90) and to rotate around a first axis (X) parallel to the rotating axis (R) at a first rotating speed, wherein a second pinion shaft (20) is configured to be mechanically coupled to the first pinion shaft (10) and to rotate around a second axis (Y) at a second rotating speed, the first axis (X) and the second axis (Y) being non-parallel.

2. The integrally geared turbomachinery system (200) of claim 1, further comprising a first bevel gear (51) mechanically coupled to the first pinion shaft (10) and a second bevel gear (52) mechanically coupled to the second pinion shaft (20), wherein the first bevel gear (51) is configured to transmit motion to the second bevel gear (52).

3. The integrally geared turbomachinery system (200) of claim 1, further comprising at least a first impeller (31), a second impeller (32) and a third impeller (33), wherein the first impeller (31) is located at a first end of the first pinion shaft (10) and rotates around the first axis (X), wherein the second impeller (32) is located at a second end of the first pinion shaft (10) and rotates around the first axis (X), and wherein the third impeller (33) is located at a first end of the second pinion shaft (20) and rotates around the second axis (Y).

4. The integrally geared turbomachinery system (200) of claim 1, wherein the first axis (X) and the second axis (Y) lie on a same horizontal plane.

5. The integrally geared turbomachinery system (200) of claim 1, wherein the first rotating speed and the second rotating speed are different.

6. The integrally geared turbomachinery system (200) of claim 1, further comprising at least one bearing (41, 42, 43) for each pinion shaft (10, 20), the bearings (41, 42, 43) being mechanically coupled to the pinion shafts (10, 20) and being configured to axially support the pinion shafts (10, 20).

7. The integrally geared turbomachinery system (200) of claim 3, wherein the first impeller (31) and the second impeller (32) are equally spaced with respect to the third impeller (33).

8. Integrally geared turbomachinery system (200) of claim 1, comprising a plurality of pinion shafts (10, 20), wherein the first axis (X) of the first pinion shaft (10) of each couple of pinion shafts (10, 20) is at different angular positions with respect to the wheel gear (90).

9. Integrally geared turbomachinery system (200) of claim 8, wherein the different angular positions are equally spaced.

10. Integrally geared turbomachinery system (200) of claim 3, further comprising a casing (210) configured to enclose the wheel gear (90) and the pinion shafts (10, 20) and to allow the flowing of fluid flows to and from the first impeller (31), the second impeller (32) and the third impeller (33).

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