Disclosed embodiments relate generally to the field of turbomachinery, and, more particularly, to a rotor structure in a turbomachine, such as a compressor, and, even more particularly, to a rotor structure with a seal assembly and method in connection with same.
Turbomachinery is used extensively in many industries, such as for performing compression of a process fluid, conversion of thermal energy into mechanical energy, fluid liquefaction, etc. One example of such turbomachinery is a compressor, such as a centrifugal compressor.
As would be appreciated by those skilled in the art, turbomachinery, such as centrifugal compressors, may involve rotors of tie bolt construction (also referred to in the art as thru bolt or tie rod construction), where the tie bolt supports a plurality of impeller bodies and where adjacent impeller bodies may be interconnected to one another by way of elastically averaged coupling techniques, such as involving Hirth couplings or curvic couplings. These coupling types use different forms of face gear teeth (straight and curved, respectively) to form a robust coupling between two components. It will be appreciated that disclosed embodiments may be practiced with pins, tabs or any other mechanical connection that can transmit torque between adjacent rotor components. That is, disclosed embodiments are not limited to Hirth couplings or curvic couplings.
These couplings and associated structures may be subject to greatly varying forces (e.g., centrifugal forces), such as from an initial rotor speed of zero revolutions per minute (RPM) to a maximum rotor speed, (e.g., as may involve tens of thousands of RPM). Additionally, these couplings and associated structures, for example, may define interior cavities in the rotor that may be exposed to contaminants and/or byproducts that may be present in process fluids processed by the compressor. In applications where toxic chemical compounds are part of the process fluid, leakage of process fluid from the rotor into the atmosphere must be appropriately inhibited.
At least in view of the foregoing considerations, the present inventors have recognized that attaining consistent high performance and long-term durability in turbomachinery, such as a centrifugal compressor, may involve appropriately sealing and guiding safely out of the rotor process fluid that may leak into the rotor during operation of the compressor.
Disclosed embodiments may, without limitation, be implemented in turbomachinery that involves a stepped tie bolt, where respective ends of the tie bolt may extend into an atmospheric pressure side of the turbomachinery. Disclosed embodiments are designed to, in a cost-effective and reliable manner, prevent process fluid, which may leak into the rotor and may flow along the tie bolt from leaking out of the rotor end to the atmosphere.
In the following detailed description, various specific details are set forth in order to provide a thorough understanding of such embodiments. However, those skilled in the art will understand that disclosed embodiments may be practiced without these specific details that the aspects of the present invention are not limited to the disclosed embodiments, and that aspects of the present invention may be practiced in a variety of alternative embodiments. In other instances, methods, procedures, and components, which would be well-understood by one skilled in the art have not been described in detail to avoid unnecessary and burdensome explanation.
Furthermore, various operations may be described as multiple discrete steps performed in a manner that is helpful for understanding embodiments of the present invention. However, the order of description should not be construed as to imply that these operations need be performed in the order they are presented, nor that they are even order dependent, unless otherwise indicated. Moreover, repeated usage of the phrase “in one embodiment” does not necessarily refer to the same embodiment, although it may. It is noted that disclosed embodiments need not be construed as mutually exclusive embodiments, since aspects of such disclosed embodiments may be appropriately combined by one skilled in the art depending on the needs of a given application.
In one non-limiting embodiment, rotor shaft 104 may define a conduit 114 through rotor shaft 104. Conduit 114 may be fluidly connected to chamber 111 to pass the fluid to, for example, first space 110. In one non-limiting embodiment, the conduit 114 through rotor shaft 104 has a first opening 116 at a radially-inward surface of rotor shaft 104 to provide fluid communication with chamber 111. Conduit 114 has a second opening 118 at a radially-outward surface of rotor shaft 104 to provide an outlet to the fluid.
As may be appreciated in
One non-limiting functionality that may be provided by seal assembly 108 is to inhibit the flow of the fluid to, for example, an atmospheric pressure side of the compressor. Another non-limiting functionality that may be provided by seal assembly 108 (e.g., in conjunction with conduit 114) is to guide the flow of the fluid to a desired location (e.g., first space 110), where the leakage can be detected, such as by way of leak detector 112. This latter functionality is utilized in the event there is a breach, for example, in a first O-ring 120 of seal assembly 108 that allows the fluid to pass into chamber 111 and in turn to conduit 114.
In one non-limiting embodiment, seal assembly 108 comprises first O-ring 120 circumferentially disposed about rotor shaft 104. The first O-ring 120 may be disposed at a first pressure side of chamber 111. In this non-limiting embodiment, seal assembly 108 further comprises a second O-ring 122 (and optionally may include further O-rings 122) circumferentially disposed about rotor shaft 104. The second O-ring 122 may be disposed at a second pressure side of chamber 111. The first pressure side of chamber 111 (e.g., the side to which the first O-ring 120 is exposed to) may be at a higher pressure compared to the second pressure side of chamber 111 (e.g., the side to which second O-ring 122 is exposed to). By way of example, the first pressure side of chamber 111 may correspond to the pressurized process side of the compressor and the second pressure side of chamber 111 may correspond to the atmospheric pressure side of the compressor.
In one non-limiting embodiment, as shown in
Without limitation, dry fluid seal system 130 may involve a tandem seal configuration involving stationary and rotatable sealing elements. Dry fluid seal system 130 may be disposed at a radially-outward segment of rotor shaft 104 and, as suggested above, may be used to provide a venting outlet 132 to fluid that otherwise would leak from chamber 111 to space 110. In one non-limiting embodiment, conduit 114 is fluidly connected to dry fluid seal system 130 to inhibit passage of the fluid to the atmospheric pressure side of the turbomachine. In one non-limiting embodiment, leak detector 112 (
In one non-limiting embodiment, a potential malfunction that may arise in connection with dry fluid seal system 130 may be evaluated based on a condition of the first O-ring 120. For example, if the potential malfunction occurs while the first O-ring 120 is in a first condition, (e.g., an intact condition of first O-ring 120, as shown in
By way of comparison, if the potential malfunction occurs while the first O-ring 120 is in a second condition, (e.g., a ruptured first O-ring 120, as schematically shown in
In one non-limiting embodiment, rotor shaft 104 may include a groove 158 configured to receive an O-ring 160 circumferentially disposed about rotor shaft 104 to seal the open end 156 of cap 150. A further O-ring 162 may be circumferentially disposed about rotor shaft 104 to provide an initial sealing point to fluid that, if left unimpeded by O-ring 162, would flow from the pressurized process side of the compressor towards the end portion 154 of tie bolt 102, such as by way of a space 164, e.g., clearance gap, between tie bolt 102 and rotor shaft 104. In this embodiment, space 164 at least in part constitute the chamber separated by the seal assembly (e.g., made up in this embodiment by cap 150 and O-rings 156, 162) from first space 110.
In one non-limiting embodiment, a thrust collar 170 may be connected to cap 150 to circumferentially engage the open end 156 of cap 150 so that, for example, the portion of the rotor shaft 104 abutting the open end 156 of cap 150 is engaged by way of a circumferential compressive force provided by thrust collar 170. That is, the open end 156 of cap 150 may be compressively affixed to the abutting portion of the rotor shaft 104. In one non-limiting embodiment, a surface 172 of the trust collar 170 that engages the open end 156 of cap 150 has a frustoconical shape, as may be appreciated in zoomed-in view 180.
In this embodiment, first space 110 may be at the atmospheric pressure side of the turbomachine, and a leak detector 182, such as a pressure-measuring device to detect a cyclical pressure variation, and/or a gas-monitor probe, may be disposed proximate the open end of the cap to generate the indication of leakage of the fluid, in the event O-rings 160 and 162, each malfunctions. For example, presuming an orifice develops at a certain circumferential location of O-ring 160, then during each revolution of the rotor, the pressure-measuring device would sense a pressure increase due to leakage of the process fluid through such orifice. Similarly, the gas-monitor probe may be selected to detect the presence of certain molecules present in the process fluid and this detection would provide an indication of leakage of fluid from the open end of the cap.
As can be appreciated in
In one non-limiting embodiment, as shown in
In one non-limiting embodiment, as shown in
In operation, disclosed embodiments permit appropriately sealing and guiding safely out of the rotor leakage of process fluid that may develop during operation of the compressor. In operation, disclosed embodiments can inhibit the flow of leakage fluid to, for example, an atmospheric pressure side of the compressor and can guide the flow of leakage fluid to a desired location, where the leakage can be detected by way of a leak detector. In operation, certain disclosed embodiments may use a seal assembly to provide indications useful to identify root causes of non-conformance that can develop in connection with a dry fluid seal system.
Filing Document | Filing Date | Country | Kind |
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PCT/US2021/053739 | 10/6/2021 | WO |