Coupling joint for interconnecting and transmitting rotational torque between adjacent impeller bodies in turbomachine

Abstract

Improved coupling joints configured to interconnect and transfer torque between adjacent impeller bodies in a turbomachine are provided. A plurality of impeller bodies are stacked on the tie bolt. Respective coupling joints are defined by features in adjacent impeller bodies to couple the adjacent impeller bodies to each other. The coupling joint involves a pair of corresponding axial engagement surfaces and a pair of corresponding radial engagement surfaces defining a coupling pilot fit. A torque transmitting device is interposed between the axial engagement surface and the radial engagement surface. The pair of axial engagement surfaces in operation define a compression joint effective to form a seal between the pair of axial engagement surfaces to prevent leakage of process fluid handled in a compressor section of the turbomachine. This allows a separate sealing arrangement to be eliminated, otherwise, for example, may involve a sleeve with an O-ring or the like.

Description

Background Art

[0001] The disclosed embodiments relate generally to the field of turbomachinery, and more particularly to an improved coupling joint configured for interconnecting and transferring torque between adjacent rotatable impeller bodies in a turbomachine.

[0002] Turbomachinery is widely used in the oil and gas industry, for example, for compressing process fluids, converting thermal energy into mechanical energy, liquefying fluids, etc. One example of such a turbomachinery is a compressor, such as a centrifugal compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Figure 1 A partial isometric view of one non-limiting embodiment of a portion of a rotor structure showing a rotatable impeller body such as may be used in industrial applications involving turbomachinery, such as but not limited to compressors (eg, centrifugal compressors, etc.).

[0004] Figure 2 is a partial cross-sectional view showing the arrangement of the tie bolts of the impeller body.

[0005] Figure 3 is an isometric view of mutually facing features of adjacent impeller bodies which combine to form a coupling joint to couple respective adjacent impeller bodies to one another and to transfer torque between adjacent impeller bodies of a turbine.

[0006] Figure 4 is a partial isometric view of certain structural features that may be arranged in combination to define a torque transfer arrangement between respective adjacent impeller bodies.

[0007] Figure 5 is a diagram used to conceptualize the nature of the engagement formed between corresponding features of a torque transmitting device.

[0008] Figure 6 is a partial cross-sectional view showing an axial joint surface of a tapered coupling joint.

[0009] Figure 7 and Figure 8 are respective isometric views showing views of the two-piece assembly relative to one another at the mid-span section of the tie bolts in an exemplary back-to-back configuration of the impeller body. DETAILED DESCRIPTION

[0010] As will be appreciated by those skilled in the art, turbomachinery such as a centrifugal compressor may include a rotor in a tie bolt configuration (also referred to in the art as a through bolt or tie rod configuration) The tie bolts are arranged to support a plurality of rotatable impeller bodies that are, for example, arranged in combination to form a compressor section of the turbomachine.

[0011] The inventors of the disclosed embodiments have recognized that in certain known rotor designs involving tie bolts, where the tie bolts, for example, may involve considerable lengths and may further involve high rotational speeds, there may be certain technical challenges associated with such rotor structures, such as tie bolt resonance and / or rotor imbalance that may be caused by deflection or radial displacement of the tie bolts relative to the rotor structure.

[0012] The disclosed embodiments utilize an improved coupling joint configured for interconnecting and effectively transmitting rotational torque between adjacent impeller bodies in a turbine. Certain structures involved in the disclosed embodiments (e.g., structures involving mutual engagement surfaces configured to partially form a coupling guide fit (also referred to in the art as a spigot joint)) effectively interconnect adjacent impeller bodies without involving a straight-tooth Hirth coupling or a curvic coupling between corresponding adjacent impeller bodies. That is, the disclosed embodiments can operate without a straight-tooth Hirth coupling or a curvic coupling to interconnect adjacent impeller bodies to each other.

[0013] Before describing in detail any disclosed embodiments, it should be understood that the application of the disclosed concepts is not limited to the details of construction and arrangement of components set forth in this specification or shown in the following drawings. The disclosed concepts may be implemented by other implementations and may be practiced or performed in various ways. Furthermore, it should be understood that the words and terminology used in the present invention are for descriptive purposes and should not be considered limiting.

[0014] Various techniques related to systems and methods will now be described with reference to the accompanying drawings, wherein the same reference numerals represent the same elements throughout. The accompanying drawings discussed below and the various embodiments for describing the principles of the present invention in this patent document are intended to be illustrative only and should not be interpreted as limiting the scope of the present invention in any way. It will be appreciated by those skilled in the art that the principles of the present invention can be implemented in any suitably arranged device. It should be understood that the functions described as being performed by certain system elements can be performed by one or more elements. Similarly, for example, an element can be configured to perform functions that can be described as being performed by a plurality of elements. Many innovative teachings of the present application will be described with reference to exemplary non-limiting embodiments.

[0015] It should be understood that the words or phrases used herein should be interpreted broadly unless explicitly limited in some examples. For example, the terms "include", "have" and "include" and their derivatives are meant to include but are not limited to. The singular forms "one", "an" and "the" are also intended to include plural forms, unless the context clearly indicates otherwise. In addition, the term "and / or" used in the present invention refers to and covers any and all possible combinations of one or more items in the relevant listed items. The term "or" is inclusive, meaning and / or, unless the context clearly indicates otherwise. The phrases "associated with..." and "associated with it" and their derivatives can mean including, included in, interconnected with, included in, connected to, or connected with, connected to, or connected with, communicated with, collaborated with, interlaced, juxtaposed, close to, bound to, or bound with, have, have... characteristics, etc. In addition, although multiple embodiments or configurations can be described herein, any features, methods, steps, components, etc. described with respect to one embodiment are equally applicable to other embodiments without specific statements to the contrary.

[0016] In addition, although the terms "first", "second", "third", etc. can be used to refer to various elements, information, functions or actions in the present invention, these elements, information, functions or actions should not be limited by these terms. On the contrary, these digital adjectives are used to distinguish between different elements, information, functions or actions. For example, the first element, information, function or action can be referred to as the second element, information, function or action, and similarly, the second element, information, function or action can be referred to as the first element, information, function or action, without departing from the scope of the present invention.

[0017] Additionally, the term "adjacent" is intended to mean that an element is in contact with another element in operation, unless the context clearly indicates otherwise. Additionally, the phrase "based on" is intended to mean "based at least in part on," unless otherwise clearly indicated. The terms "about" or "substantially" or similar terms are intended to encompass variations in values ​​within the standard industry manufacturing tolerance for that dimension. If no industry standard is available, a variation of 20% will fall within the meaning of these terms unless otherwise indicated.

[0018] Figure 1 A partial isometric view of one non-limiting embodiment of the disclosed rotor structure 100 is shown, which may be used in industrial applications involving turbomachinery, such as, but not limited to, compressors (eg, centrifugal compressors, etc.).

[0019] In an exemplary embodiment, a plurality of impeller bodies 102 are stacked adjacent to each other on tie bolts 104 ( Figure 2 ). To simplify the explanation, Figure 1Only two impeller bodies 102 are shown in FIG. In an example embodiment, as set forth in greater detail below, respective coupling joints 106 are defined by respective adjacent ones of the plurality of impeller bodies 102 to interconnect and transfer torque between the adjacent impeller bodies.

[0020] In one embodiment, the rotor shaft 105 ( Figure 2 ) may be secured to one end of the tie bolt 104. A second rotor shaft (not shown) may be secured to the other end of the tie bolt. The rotor shaft may be referred to in the art as a stub shaft. It should be understood that in certain embodiments, more than two rotor shafts may be included. Without limitation, the coupling techniques described herein in conjunction with the coupling joint 106 may be used to interconnect the following components to one another: adjacent impeller bodies; impeller bodies and rotor shafts; or adjacent rotor shafts. That is, although the following description focuses on interconnection and torque transfer between adjacent impeller bodies, generally such coupling joints may be equally effective for interconnection and torque transfer between any of the various rotatable components associated with the rotor structure of the turbine, such as interconnection and torque transfer between an impeller body and an adjacent rotor shaft. It should also be understood that the disclosed embodiments may be used without limitation and regardless of the specific arrangement of the impeller bodies, which may include, for example, a straight-through arrangement of the impeller bodies or a back-to-back arrangement of the impeller bodies.

[0021] In an example embodiment, Figure 1 As schematically shown in FIG. 1 , each corresponding coupling joint may be defined by a pair of corresponding axial engagement surfaces 108, which may extend between a radial outer diameter (do) and a radial inner diameter (di). In an example embodiment, the radial outer diameter (do) of the pair of corresponding axial engagement surfaces 108 may constitute the radial outermost diameter of the corresponding coupling joint 106. The pair of corresponding axial engagement surfaces 108 extending to a position constituting the radial outermost diameter of the corresponding coupling joint 106 is conducive to improving the rotor bending stiffness and overall improving the rotational dynamics performance of the rotor structure.

[0022] like Figure 1 As further schematically shown in FIG. 1 , in an example embodiment, the respective coupling joints 106 may be further defined by a pair of corresponding radial engagement surfaces 110. Figure 4 As can be better understood in FIG. 1 , one of the pair of corresponding radial engagement surfaces 110 can be defined by an axial protrusion 112 from one of the adjacent impeller bodies, and the other of the pair of corresponding radial engagement surfaces 110 can be defined by an axially extending hole 114 in the other of the adjacent impeller bodies. The axially extending hole 114 is configured to receive the axial protrusion 112. It should be understood that the pair of corresponding radial engagement surfaces 110 form a coupling guide fit between the corresponding adjacent impeller bodies 102.

[0023] In an exemplary embodiment, the torque transfer device 116 is further defined by the corresponding adjacent impeller body 102. Figure 1 , the torque transfer device 116 is interposed between the pair of corresponding axial engagement surfaces 108 and the pair of corresponding radial engagement surfaces 110. In one embodiment, a small radial gap or clearance may be located between the pair of corresponding axial engagement surfaces 108 and the pair of corresponding radial engagement surfaces 110.

[0024] As in Figure 3 As can be better understood in the embodiment of the present invention, the torque transmitting device 116 includes a plurality of circumferentially elongated tabs 120 extending from one of the adjacent impeller bodies 102 and a plurality of apertures 122 each correspondingly configured to receive a corresponding elongated tab 120 of the plurality of circumferentially elongated tabs. In an exemplary embodiment, the plurality of circumferentially elongated tabs 120 and the plurality of apertures 122 are each spaced apart in the circumferential direction of the torque transmitting device 116.

[0025] In an exemplary embodiment, the number of apertures 122 may be greater than the number of circumferential elongated tabs. This arrangement facilitates flexibility in handling alignment tolerances between respective apertures 122 and respective elongated tabs 120. For example, this will allow for finer timing intervals between respective apertures 122 and respective circumferential elongated tabs 120, and provide more flexibility to find additional angular position options for appropriately interconnecting respective apertures 122 and respective circumferential elongated tabs 120, compared to an arrangement in which the number of circumferential elongated tabs 120 is equal to the number of respective apertures 122.

[0026] like Figure 5 As shown, each circumferentially elongated tab 120 has a cross-section (e.g., a non-circular cross-section of the circumferential elongation (schematically represented by double-headed arrow 126)) configured to increase the shear area relative to a circular area of ​​a given thickness, for example, in the radial direction of the torque transmitting device 116 (schematically represented by arrow 124). In an example embodiment, each respective circumferentially elongated tab 120 is configured to provide a surface engagement with a corresponding surface of a respective receiving aperture 122 at an arcuate segment (schematically represented by curved arrow 128) of the respective circumferentially elongated tab 120. This arrangement effectively suppresses a centering effect that may otherwise occur between respective adjacent impeller bodies 102, for example, if the receiving aperture 122 does not have a circumferentially elongated cross-section that matches the circumferentially elongated tab 120. It will be appreciated that the centering function between respective adjacent impeller bodies 102 can be achieved by the radial engagement surface 110.

[0027] In an example embodiment, Figure 6As shown, a respective one of the pair of corresponding axial engagement surfaces 108 has a taper (schematically represented by angle α) that facilitates relatively more uniform surface contact pressure between the pair of corresponding axial engagement surfaces as one surface travels toward the radial outer diameter of the coupling joint. For example, as the rotor rotates, the heel 102′ ( Figure 1 ) tends to be larger than the toe 102" ( Figure 1 ) grows more radially, and the taper is arranged to inhibit the axial engagement surface 108 from separating at a position corresponding to the radial outer diameter (do).

[0028] Figure 7 and Figure 8 1 are respective isometric views showing views relative to each other of an assembly 200 that may be located at a mid-span section of a tie bolt 104 in an example back-to-back configuration of an impeller body. In an exemplary embodiment, the assembly 200 includes a first subassembly 202 defining a tolerance ring carrier having a radially inner portion 204 configured to engage the mid-span section of the tie bolt. The tolerance ring carrier 202 has a radially outer portion 206 connected to a second subassembly 210 that defines a dividing wall spacer. In a non-limiting embodiment, the tolerance ring carrier 202 is secured to the dividing wall spacer by a pilot fit.

[0029] As further shown, the tolerance ring carrier 202 has a spring biasing mechanism 212 configured to adjust the radial stiffness at the mid-span section of the tie bolt 104. The spring biasing mechanism may be selected from various forms of biasing mechanisms, such as tolerance rings, wave springs, C-springs, and leaf springs.

[0030] In one exemplary embodiment, the tolerance ring carrier 202 includes a plurality of first grooves 214 extending radially inwardly from an outer diameter of the tolerance ring carrier. Figure 8 ). Additionally, the divider wall spacer 210 includes a plurality of second grooves 216 extending radially outward from an inner diameter of the divider wall spacer 210. In one non-limiting embodiment, the plurality of first grooves 214 are spaced apart circumferentially of the tolerance ring carrier, and the plurality of second grooves are spaced apart circumferentially of the divider wall spacer 210. In one example embodiment, each respective groove 214 of the plurality of first grooves is circumferentially inserted between adjacent grooves 216 of the plurality of second grooves. The plurality of second grooves 216 extending radially outward from the inner diameter of the divider wall spacer 210 effectively allows the divider wall spacer 210 to grow as if it had a larger bore. Similarly, the plurality of first grooves 214 extending radially inward from the outer diameter of the tolerance ring carrier effectively accommodates additional radial growth of the tolerance ring carrier 202.

[0031] It should be understood that the dual subassembly design forming assembly 200 is configured such that, for example, the radial growth of the dividing wall spacer 210 at the outer diameter matches the radial growth of the adjacent impeller body. In addition, the radial growth of the tolerance ring carrier 202 should be selected so as not to exceed the allowable preload range of the spring biasing mechanism 212.

[0032] In operation, when the tie bolts have been appropriately subjected to a high level of tension to hold the impeller body together, the pair of corresponding axial engagement surfaces 108 ( Figure 1 ) form a compression joint between each other. The compression joint effectively defines a seal between a pair of corresponding axial joint surfaces 108 at each corresponding coupling joint 106 to prevent leakage of the process fluid processed in the compressor section of the turbine.

[0033] In operation, the parallelism, flatness and perpendicularity of the interengaging axial faces can be properly controlled, which helps prevent angular misalignment and allows the rotor to be designed with a relatively large rotor diameter, thereby increasing rotor stiffness.

[0034] As described above, in operation, the interengaging surfaces effectively form a metal-to-metal seal that prevents process fluid from entering the tie bolt area and thereby allows for the elimination of discontinuous sealing components, such as a sleeve with an O-ring or similar discontinuous sealing device.

[0035] In operation, the torque transfer device having the elongated tabs provides technical advantages, for example, over at least certain known designs involving dowel pins, which in turn involve cumbersome precision fixtures for installation. In addition, the elongated tabs of the present invention allow for a relatively large cross-sectional shear area compared to the shear cross-section (e.g., circular cross-section) provided, for example, by dowel pins, which relatively have a reduced shear area and would reduce the amount of torque that can be transferred through the rotor shaft of a given turbine. Thus, the disclosed embodiments are believed to provide more flexibility, for example, in relation to drive through applications.

[0036] Although at least one exemplary embodiment of the present disclosure has been described in detail, those skilled in the art will appreciate that various changes, substitutions, variations, and improvements may be made herein without departing from the scope of the invention in its broadest form.

[0037] Nothing in this application should be read as implying that any particular element, step, act, or function is an essential element that must be included within the scope of the claims. The scope of the patented subject matter is limited only by the claims that are issued. Furthermore, unless a participle is followed by the exact words "means for...", none of the claims are intended to involve a means-plus-function claim construction.

Claims

1. A turbine having a rotor structure, comprising: Tighten the bolts; a plurality of impeller bodies stacked adjacent to each other on the tie bolts; a respective coupling joint defined by respective adjacent impeller bodies among the plurality of impeller bodies to couple the respective adjacent impeller bodies to each other, the respective coupling joint being defined by: a pair of corresponding axial engagement surfaces extending between a radially outer diameter and a radially inner diameter, wherein the radially outer diameter of the pair of corresponding axial engagement surfaces comprises a radially outermost diameter of the respective coupling joint; and a pair of corresponding radial engagement surfaces, one of the pair of corresponding radial engagement surfaces being defined by an axial projection of one of the adjacent impeller bodies and the other of the pair of corresponding radial engagement surfaces being defined by an axially extending bore in the other of the adjacent impeller bodies, the axially extending bore being configured to receive the axial projection; as well as A torque transfer device is further defined by the respective adjacent ones of the plurality of impeller bodies, the torque transfer device being interposed between the pair of corresponding axial engagement surfaces and the pair of corresponding radial engagement surfaces.

2. The turbine according to claim 1, wherein: The pair of corresponding axial engagement surfaces and the pair of corresponding radial engagement surfaces form a coupling guide fit between the respective adjacent impeller bodies.

3. The turbine according to claim 1, wherein: The torque transmitting device includes a plurality of circumferentially elongated tabs projecting from one of the adjacent impeller bodies and a plurality of apertures each respectively configured to receive a corresponding one of the plurality of circumferentially elongated tabs.

4. The turbine according to claim 2, wherein: Each circumferentially elongated tab has a cross-section configured to increase shear area relative to a circular area of ​​a given thickness in a radial direction of the torque transmitting device.

5. The turbine according to claim 4, wherein: Each respective circumferential elongated tab is configured to provide surface engagement with a corresponding surface of a respective receiving aperture at an arcuate segment of the respective circumferential elongated tab.

6. The turbine according to claim 3, wherein: The plurality of circumferentially elongated tabs and the plurality of apertures are each spaced apart in a circumferential direction of the torque transmitting device.

7. The turbine according to claim 6, wherein: The number of the apertures is greater than the number of the circumferential elongated tabs.

8. The turbine according to claim 3, wherein: The circumferential elongated tabs are each integrally constructed to form a single piece with the impeller body from which they protrude.

9. The turbine according to claim 1, wherein: A respective one of the pair of corresponding axial engagement surfaces has a taper configured to inhibit separation of the axial engagement surfaces at the radial outer diameter during operation of the turbine.

10. The turbine according to claim 1, wherein: The plurality of impeller bodies includes impeller bodies arranged back to back.

11. The turbine of claim 10 further comprising an assembly at the mid-span section of the tie bolts, the assembly comprising a first subassembly defining a tolerance ring carrier, the tolerance ring carrier having a radially inner portion configured to engage the mid-span section of the tie bolts, the tolerance ring carrier having a radially outward portion connected to a second subassembly defining a dividing wall spacer.

12. The turbine according to claim 11, wherein: The tolerance ring carrier has a spring biasing mechanism configured to adjust the radial stiffness at a mid-span section of the tie bolt.

13. The turbine according to claim 12, wherein: The spring biasing mechanism is selected from the group consisting of a tolerance ring, a wave spring, a C-spring and a leaf spring.

14. The turbine according to claim 12, wherein: The tolerance ring carrier includes a plurality of first grooves extending radially inward from an outer diameter of the tolerance ring carrier.

15. The turbine according to claim 14, wherein: The dividing wall spacer includes a plurality of second grooves extending radially outward from an inner diameter of the dividing wall spacer.

16. The turbine according to claim 15, wherein: The plurality of first grooves are spaced apart in the circumferential direction of the tolerance ring carrier, and wherein the plurality of second grooves are spaced apart in the circumferential direction of the partition wall spacer, wherein each respective groove of the plurality of first grooves is circumferentially inserted between adjacent grooves of the plurality of second grooves.

17. The turbine of claim 1, wherein: The plurality of impeller bodies include impeller bodies arranged in a straight-through manner.

18. The turbine of claim 1, wherein: The plurality of impeller bodies define a compressor section of the turbomachine, and wherein the pair of corresponding axial engagement surfaces form a compression joint therebetween that effectively defines a seal therebetween to prevent leakage of a process fluid processed in the compressor section of the turbomachine.

19. The turbine according to claim 1, wherein: The turbomachine is a centrifugal compressor.

20. The turbine of claim 1, further comprising a rotor shaft at one end of the tie bolt, and a corresponding coupling joint defined by the rotor shaft and an impeller body adjacent the rotor shaft, wherein: The other of the respective coupling joints is arranged to couple the respective impeller body and the rotor shaft to each other.

Images