Compressor rotor with a sealing element

Abstract

A compressor rotor for a turbomachine, such as a compressor, is provided. The disclosed embodiments may benefit from a sealing element arranged to prevent process fluid handled by the compressor from passing over corresponding face tooth couplings. The sealing element may be attached to an adjacent rotor component (e.g., an adjacent impeller body) by a sliding fit connection or an interference fit connection with one of the adjacent components, and the sealing element may be attached to another adjacent rotor component by an elastically flexible frustoconical inner surface of the sealing element, the elastically flexible frustoconical inner surface allowing the sealing element to be placed in a spring-loaded state that generates a biasing force for circumferentially clamping onto a frustoconical outer surface of another adjacent rotor component. This arrangement facilitates user-friendly assembly / dismantling of the sealing element relative to the adjacent rotor components.

Description

Background Art

[0001] The disclosed embodiments generally relate to the field of turbomachinery and, more particularly, to rotor mechanisms for turbines, such as compressors.

[0002] Turbomachinery is widely used in the oil and gas industry, such as for performing compression of process fluids, conversion of thermal energy into mechanical energy, fluid liquefaction, etc. An example of such turbomachinery is a compressor, such as a centrifugal compressor. BRIEF DESCRIPTION OF THE DRAWINGS

[0003] Figure 1 A partial cross-sectional view illustrating a non-limiting embodiment of the disclosed rotor structure as may be used in industrial applications involving turbomachinery, such as but not limited to centrifugal compressors.

[0004] Figure 2 An enlarged cross-sectional view illustrating a non-limiting embodiment of the disclosed seal element for a compressor rotor and two adjacent rotor components to which the seal element is attached. The seal element is capable of moving between a first position (e.g., a pre-assembled position) and a second position (e.g., an assembled position). Figure 2 An illustration of the disclosed seal element in the pre-assembled position.

[0005] Figure 3 An illustration of the Figure 2 disclosed seal element shown in

[0006] Figure 4 is Figure 2 and Figure 3 a superposition of which illustrates the dashed outline of the seal element ( Figure 3 ) in the assembled position. The dashed outline of the seal element is superimposed on the seal element shown in Figure 2 in the pre-assembled position.

[0007] Figure 5 An enlarged cross-sectional view illustrating another non-limiting embodiment of the disclosed seal element and two adjacent rotor components to which the seal element is attached. The seal element is capable of moving between the pre-assembled position and the assembled position. Figure 5 An illustration of the disclosed seal element in the pre-assembled position.

[0008] Figure 6 An illustration of the Figure 5 disclosed seal element shown in

[0009] Figure 7 is Figure 5 and Figure 6superposition thereof, which illustrates the dashed outline of the sealing element when in the assembled position ( Figure 6 ). The dashed outline of the sealing element is superimposed on the Figure 5 sealing element shown in the pre-assembled position. DETAILED DESCRIPTION

[0010] As will be understood by those skilled in the art, turbomachinery, such as a centrifugal compressor, may involve a rotor with a tension bolt structure (also known as a through-bolt or tie-rod structure in the art), where the tension bolts support a plurality of impeller bodies, and where adjacent impeller bodies may be interconnected with each other by an elastic averaging coupling technique, such as an end-face tooth coupling or a flexure coupling. These connector types use different forms of planar gear teeth (straight and curved, respectively) to form a secure connection between two components.

[0011] These couplings and associated structures can be subjected to widely varying forces (e.g., centrifugal forces), such as changing from an initial rotor speed of zero revolutions per minute (RPM) to a maximum rotor speed (e.g., as may be involved in tens of thousands of RPM). Additionally, these couplings and associated structures may be exposed to contaminants and / or by-products that may be present in the process fluid handled by the compressor. If so exposed, such couplings and associated structures may potentially be affected in a manner that can impact their long-term durability. For example, a combination of carbon dioxide (CO2), liquid water, and high pressure levels can result in the formation of carbonic acid (H2CO3), a compound that can cause corrosion, rusting, or pitting of certain steel components. Physical debris may also be present in the process fluid, which can potentially affect the function and durability of the end-face tooth coupling and associated structures if allowed to reach them.

[0012] In view of the foregoing considerations, the inventors have recognized that achieving consistent high performance and long-term durability in a centrifugal compressor, for example, may involve appropriately covering the corresponding end-face tooth couplings with a suitable sealing structure to prevent the process fluid handled by the compressor from passing over the corresponding end-tooth face couplings, and thus improving the problems discussed above.

[0013] In the following detailed description, various specific details are set forth to provide a thorough understanding of these embodiments. However, those skilled in the art will understand that the disclosed embodiments may be practiced without these specific details, that aspects of the present invention are not limited to the disclosed embodiments, and that aspects of the present invention may be practiced in various alternative embodiments. In other instances, methods, processes, and components that will be well understood by those skilled in the art are not described in detail to avoid unnecessary and cumbersome explanations.

[0014] In addition, various operations may be described as a number of discrete steps performed in a manner that aids in understanding embodiments of the present invention. However, unless otherwise indicated, the order of the described steps should not be construed as implying that these operations need to be performed in the order in which they are presented, nor should it be construed that these operations are even order-dependent. Further, repeated use of the phrase "in one embodiment" does not necessarily refer to the same embodiment, but the phrase may refer to the same embodiment. It should be noted that the disclosed embodiments need not be construed as mutually exclusive embodiments, as those skilled in the art may appropriately combine aspects of these disclosed embodiments according to the needs of a given application.

[0015] Figure 1 FIG. shows a partial cross-sectional view of a non-limiting embodiment of the disclosed rotor compressor 100 as may be used in industrial applications involving turbomachinery, such as but not limited to a compressor (e.g., a centrifugal compressor, etc.).

[0016] In one disclosed embodiment, the tension bolt 102 extends along the rotor axis 103 between a first end and a second end of the tension bolt 102. To avoid visual clutter, only one end of the tension bolt is shown, and for the purposes of this disclosure, the structure and / or operational relationships associated with each end of the tension bolt 102 are the same. The rotor shaft 104 may be fixed to the first end of the tension bolt 102. A second rotor shaft may be fixed to the second end of the tension bolt (as noted above, neither the second end of the tension bolt nor the second rotor shaft is shown). A rotor shaft may be referred to in the art as a stub shaft. It will be understood that in some embodiments, more than two rotor shafts may be involved.

[0017] A plurality of impeller bodies may be disposed between the rotor shafts and the plurality of impeller bodies are supported by the tension bolt 102. For simplicity of illustration, only a portion of the first impeller body 1061 and the second impeller body 1062 are shown in Figure 1 FIG. For example, the rear side portion of the first impeller body 1061 is mechanically coupled to the inlet side of the second impeller body 1062 by a face gear coupling 108 for rotation about the rotor axis 103. In the illustrated embodiment, additional face gear couplings 109 may be used to mechanically couple the inlet side of the impeller body 1061 and the adjacent rotor shaft 104, respectively. It will be understood that the foregoing arrangement of the impeller bodies and the face gear couplings is merely an example and should not be construed in a limiting sense.

[0018] Sealing elements 120 are attached to the respective outer surfaces of any two adjacent impeller bodies (e.g., adjacent impeller bodies 1061, 1062). The sealing elements 120 can be arranged (e.g., along 360 degrees) to span the circumferential extension spacing 126 between the adjacent impeller bodies 1061, 1062 to prevent process fluid handled by the compressor from passing through on the respective face gear couplings 108. Similarly, sealing elements 130 are attached to the respective outer surfaces of the impeller body and an adjacent rotor shaft (e.g., impeller body 1061 and adjacent rotor shaft 104) to prevent process fluid handled by the compressor from passing through on the face gear coupling 109.

[0019] As will be elaborated in more detail below, the sealing element 120 is capable of moving between a first position (pre-assembly position) and a second position (assembly position). The aforementioned movable feature of the sealing element 120 equally applies to the sealing element 130. Figure 2 The sealing element 120 is illustrated in the first position, and Figure 3 the sealing element 120 is illustrated in the second position.

[0020] Figure 4 is Figure 2 and Figure 3 a superposition of, which illustrates the profile (schematically indicated by the dashed line) of the sealing element ( Figure 3 ) in the assembled position, which profile is superposed on the sealing element in the pre-assembled position shown in Figure 2 .

[0021] As can be better understood in Figure 2 and Figure 3 , for example, the sealing element 120 can have a first end 121 mechanically coupled to a second rotor component 106” and a second end 123 mechanically coupled to a first impeller body 106’. Generally, the second rotor component 106” can be any given rotor component, such as a second impeller body, a rotor shaft, or a balance piston, which is adjacent to the first impeller body 106’ and is mechanically connected to the first impeller body 106’ through a face gear coupling for rotation about the rotor axis, as discussed above in the context of Figure 1 . Thus, regardless of whether the second rotor component 106” is an impeller body, a rotor shaft, or a balance piston, the following description can apply similarly. For simplicity of illustration, the face gear coupling that connects the first impeller body 106’ to the second rotor component 106” is not illustrated in Figures 2 to 7 .

[0022] By way of non - limitation, the first impeller body 106’ may define a frustoconical outer surface 140 having a first angle, the first angle being fixed relative to the rotor axis. The second end 123 of the sealing element 120 may define a frustoconical inner surface 142 having a second angle, the second angle being elastically variable relative to the rotor axis and thus variable relative to the frustoconical outer surface 140.

[0023] As can be understood in Figure 2 In a first position (e.g., a pre - assembled position), the first angle of the frustoconical outer surface 140 and the second angle of the frustoconical inner surface 142 are such that the frustoconical surfaces 140, 142 are allowed to contact each other at point 144, for example, which may define an initial contact point of the second end 123 of the sealing element 120 with the frustoconical outer surface 140. As can be understood in Figure 3 In a second position (e.g., an assembled position), the first angle of the frustoconical outer surface 140 and the second angle of the frustoconical inner surface 142 are such that the frustoconical surfaces 140, 142 are allowed to form a surface - to - surface engagement, as schematically represented by the double arrow 146.

[0024] That is, when the sealing element 120 moves together with the second rotor component 106” in a direction opposite to the first axial end 121 of the sealing element 120 towards the first impeller body 106’ and engages with the frustoconical outer surface 140 of the first impeller body 106’, the frustoconical inner surface 142 of the sealing element 120 elastically flexes, for example, in response to an axial compressive load applied by the second rotor component 106” relative to the first impeller body 106’. The flexure of the frustoconical inner surface 142 of the sealing element 120 causes the sealing element to be in a spring - loaded state, which in turn generates a biasing force arranged to circumferentially clamp onto the frustoconical outer surface 140 of the first impeller body 106’. It will be understood that, for example, for maintenance operations, the sealing element 120 can be moved from the second position (assembled position) to the first position, which in this case will allow the user - friendly removal and / or replacement of the sealing element 120.

[0025] As Figures 2 to 3 As shown in, the second rotor component 106” may include a cylindrical outer surface 141, wherein the first end 121 of the sealing element 120 may be attached to the cylindrical outer surface 141 by a slip fit or by an interference fit (an interference fit may also be referred to as a press fit in the art), and, for example, this may involve a shrink - fit technique for attaching the first end 121 of the sealing element 120 to the cylindrical outer surface 141 of the second rotor component 106”.

[0026] In a non-limiting embodiment, a first circumferentially extending groove 160 may be provided in the frustoconical outer surface 140 of the first impeller body 106', and a first sealing member 162 may be positioned in the groove 160 to form a seal between the frustoconical outer surface 140 of the first impeller body 106' and the sealing element 120.

[0027] In a non-limiting embodiment, a second circumferentially extending groove 170 may be provided in the cylindrical outer surface 141 of the second rotor member 106", and a second sealing member 172 may be positioned in the groove 170 to form a seal between the cylindrical outer surface 141 of the second rotor member 106" and the sealing element 120.

[0028] Non-limitingly, the sealing member 162 or the sealing member 172 may be an O-ring sealing member, a C-ring sealing member, a leaf-shaped sealing member, an omega-shaped sealing member, a metal sealing member, a metal fabric sealing member or other sealing member. The O-ring sealing member may include an elastic material or a non-elastic material, such as a PTFE (polytetrafluoroethylene) material. As will be understood by those skilled in the art, the metal fabric seal may include a high-temperature resistant material such as metal, ceramic or polymer fibers that can be woven, knitted or otherwise pressed into the fabric layer.

[0029] As may be Figure 4 understood, the angle θ schematically represents the angle at which the frustoconical inner surface 142" of the sealing element 120 will flex to circumferentially clamp onto the frustoconical outer surface 140 of the first impeller body 106' when in the second position (e.g., the assembled position). The frustoconical inner surface 142' represents the sealing element 120 in the first position, where the frustoconical inner surface 142' is at an angle that allows the frustoconical surfaces 140, 142' to contact each other at point 144.

[0030] In a non-limiting embodiment, as Figures 2 to 3 shown, the first impeller body 106' may define a first outer surface 148 having a first profile, the second rotor member 106" may define a second outer surface 150 having a second profile, and the sealing element 120 may define an outer surface 122 that provides a continuous profile transition between the first profile and the second profile.

[0031] In Figures 2 to 3In the illustrated embodiment, the outer surface 122 of the sealing element 120 may include a curved profile transition between a first profile defined by the first outer surface 148 of the first impeller body 106' and a second profile defined by the second outer surface of the second rotor member 106". That is, the profile transition defined by the outer surface 122 of the sealing element 120 may include a single type of profile geometry, such as a curved profile geometry.

[0032] In contrast, in Figures 5 to 6 the illustrated embodiment, the outer surface 122' of the sealing element 120' may include a cylindrical profile extending from a first end 121 of the sealing element 120' to a point 125 (which is located between the first end 121 and the second end 123 of the sealing element 120'), at which point the outer surface 122' of the sealing element 120' changes to a non-cylindrical profile, such as a curved profile. That is, the profile transition defined by the outer surface 122' of the sealing element 120' may include two different types of profile geometries, such as a cylindrical profile and a curved profile.

[0033] The other structural and / or operational features described above in the context of the sealing element 120 in Figures 2 to 4 also apply to the sealing element 120'. For example, the sealing element 120' is capable of moving between a first position (pre-assembled position) and a second position (assembled position). Figure 5 illustrates the sealing element 120' in the first position, and Figure 6 illustrates the sealing element 120' in the second position. Figure 7 is Figure 5 and Figure 6 a superposition of, which illustrates the profile (schematically represented by a dashed line) of the sealing element 120' ( Figure 6 ) in the assembled position, which profile is superposed on the sealing element 120' shown in Figure 5 in the pre-assembled position. Thus, these structural and / or operational features have been described in sufficient detail in the context of Figures 2 to 4 and will not be repeated here so as to spare the reader from tedious and pedantic repetition.

[0034] In operation, the disclosed embodiments use a sealing element that is suitably arranged to cover the face gear coupling and effectively prevent process fluid handled by the compressor from passing over the corresponding face gear coupling, and thereby prevent the face gear coupling and associated structures from potentially being exposed to contaminants, chemical by-products, and / or physical debris.

[0035] In operation, the disclosed embodiments allow for user-friendly assembly of the sealing element onto the respective outer surfaces of any two adjacent rotor components, such as adjacent impeller bodies or a rotor shaft and an adjacent impeller body. Additionally, the disclosed embodiments allow for user-friendly disassembly of the sealing element from the respective outer surfaces of any two such adjacent rotor components, which, for example, facilitates maintenance operations.

[0036] Although the embodiments of the present disclosure have been disclosed in an exemplary form, it will be apparent to those skilled in the art that many modifications, additions, and deletions can be made to the embodiments of the present disclosure without departing from the scope of the invention and its equivalents as set forth in the appended claims.

Claims

1. A compressor rotor, comprising: A tension bolt that extends along the rotor axis; A first rotor shaft coupled to the tension bolt; A second rotor shaft coupled to the tension bolt; A first impeller body disposed between the first rotor shaft and the second rotor shaft, the first impeller body including a frustoconical outer surface having a first angle relative to the rotor axis; A second impeller body disposed between the first rotor shaft and the second rotor shaft; A face gear coupling positioned to couple the first impeller body and the second impeller body for rotation about the rotor axis; and A sealing element having a first end coupled to the second impeller body and a second end defining a frustoconical inner surface having a second angle, the second angle being variable relative to the rotor axis, the sealing element being movable between a first position and a second position, in the first position, the first angle of the frustoconical outer surface and the second angle of the frustoconical inner surface permit the frustoconical surfaces to contact each other at a point, in the second position, the first angle of the frustoconical outer surface and the second angle of the frustoconical inner surface permit the surfaces to form a surface-to-surface engagement.

2. The compressor rotor according to claim 1, wherein, The first impeller body defines a first outer surface having a first profile, the second impeller body defines a second outer surface having a second profile, and the sealing element defines an outer surface that provides a continuous transition between the first profile and the second profile.

3. The compressor rotor according to claim 2, wherein, The outer surface of the sealing element includes a cylindrical profile that extends from the second end of the sealing element to the point where the outer surface of the sealing element transitions to a non-cylindrical profile.

4. The compressor rotor according to claim 1, wherein, The second impeller body includes a cylindrical outer surface, wherein the first end of the sealing element is attached to the cylindrical outer surface by a slip fit or an interference fit.

5. The compressor rotor according to claim 4, further comprising a first circumferentially extending groove and a first sealing member, the first circumferentially extending groove being located in the frustoconical outer surface of the first impeller body, and the first sealing member being positioned in the first circumferentially extending groove to form a seal between the frustoconical outer surface of the first impeller body and the sealing element.

6. The compressor rotor according to claim 5, wherein, The first sealing member in the first circumferentially extending groove is an O-ring.

7. The compressor rotor according to claim 5, further comprising a second circumferentially extending groove and a second sealing member, the second circumferentially extending groove being located in the cylindrical outer surface of the second impeller body, and the second sealing member being positioned in the second circumferentially extending groove to form a seal between the cylindrical outer surface of the second impeller body and the sealing element.

8. The compressor rotor according to claim 7, wherein, The second sealing member in the second circumferentially extending groove is an O-ring.

9. The compressor rotor according to claim 1 further includes another end face tooth coupler and another sealing element. The another end face tooth coupler is positioned to couple a corresponding one of the first rotor shaft and the second rotor shaft to an adjacent impeller body. The adjacent impeller body includes a frustoconical outer surface having a first angle relative to the rotor axis. The another sealing element has a first end coupled to the corresponding rotor shaft and a second end defining a frustoconical inner surface having a second angle that can vary relative to the rotor axis. The another sealing element is movable between a first position and a second position. In the first position of the another sealing element, the first angle of the frustoconical outer surface of the adjacent impeller body and the second angle of the frustoconical inner surface of the corresponding rotor shaft allow the frustoconical surfaces to contact each other at a point. In the second position of the another sealing element, the first angle of the frustoconical outer surface and the second angle of the frustoconical inner surface allow the surfaces to form a surface-to-surface engagement.

10. The compressor rotor according to claim 9, wherein, The adjacent impeller bodies define a first outer surface having a first profile, the respective rotor shafts define a second outer surface having a second profile, and the other sealing element defines another outer surface that provides a continuous transition between the first profile of the adjacent impeller bodies and the second profile of the respective rotor shafts.

11. The compressor rotor according to claim 10, wherein, The respective rotor shafts include a cylindrical outer surface, wherein the first end of the other sealing element is attached to the cylindrical outer surface by a slip fit or an interference fit.

12. The compressor rotor according to claim 11 further includes a first circumferentially extending groove and a first sealing member. The first circumferentially extending groove is located in the frustoconical outer surface of the adjacent impeller body. The first sealing member is positioned in the first circumferentially extending groove to form a seal between the frustoconical outer surface of the adjacent impeller body and the another sealing element.

13. The compressor rotor according to claim 12, wherein, The first sealing member in the first circumferentially extending groove is an O-ring.

14. The compressor rotor according to claim 12 further includes a second circumferentially extending groove and a second sealing member. The second circumferentially extending groove is located in the cylindrical outer surface of the corresponding rotor shaft. The second sealing member is positioned in the second circumferentially extending groove to form a seal between the cylindrical outer surface of the corresponding rotor shaft and the another sealing element.

15. The compressor rotor according to claim 14, wherein, The second sealing member in the second circumferentially extending groove is an O-ring.

16. The compressor rotor according to claim 7 or claim 14, wherein, The first sealing member and / or the second sealing member is selected from the group consisting of an O-ring sealing member, a C-ring sealing member, a leaf sealing member, an omega sealing member, a metal sealing member, and a metal fabric sealing member.

17. A centrifugal compressor includes the compressor rotor according to any one of the preceding claims.

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