Patent Application
20100239419
The present disclosure relates to fluid machinery, and more particularly to high pressure casings for such machinery.
Fluid machinery, such as centrifugal compressors, typically include a casing for containing working components, such as one or more impellers mounted on a rotatable shaft. The casing includes one or more inlets for directing fluid inwardly toward the compressor working components and one or more outlets for directing pressurized fluid outwardly from the casing for subsequent processing or ultimate usage. Further, compressor casings often include one or more openings to provide access to maintain or repair components of the compressor, for example, shaft bearings, etc. Such access openings must be closed by a hatch or cover during normal compressor use.
Since a variety of compressors are operated at relatively high pressure, the access covers are required to resist this high pressure, and are therefore often relatively thick, require the machining of a protrusion for mounting the cover, and are typically secured by a relatively large number of fasteners or bolts. Since these compressors may operate in hostile environments such as subsea applications, the cover bolts could be subject to deterioration, which may lead to failure of the entire compressor.
Embodiments of the disclosure may provide a closure device having at least one access opening. The closure device may include a cover member movably disposed within an interior chamber of the casing so as to be slidably displaceable along a central axis between an open and a closed position, the cover member being spaced at least partially axially from the access opening in the open position so as to permit access to the interior chamber and generally extending across and substantially obstructing the at least one access opening in the closed position. Further, the cover member may generally extend across and substantially obstructs the access opening in the closed position.
Embodiments of the disclosure may further provide a compressor casing assembly. The casing assembly may include a casing having a central axis, an inner surface defining an interior chamber, an opposing outer surface, and at least one access opening extending generally radially between the casing inner and outer surfaces, and a closure device including a cover member movably disposed within the interior chamber so as to be slidably displaceable generally along the central axis between an open and a closed position, the cover member being spaced at least partially axially from the access opening in the open position so as to permit access to the interior chamber and generally extends across and substantially obstructs the access opening in the closed position.
Embodiments of the disclosure may further provide a closure device for a high pressure compressor casing, the casing having a central axis, an inner surface defining an interior chamber, an opposing outer surface, and an access opening extending between the casing inner and outer surfaces. The closure device may include a retainer body disposed within the casing interior chamber generally adjacent to the access opening and having a central bore. A cover member is movably disposed within the central bore of the retainer body so as to be slidably displaceable generally along the casing central axis between an open and a closed position. The cover member is spaced at least partially axially from the access opening in the open position so as to permit access to the interior chamber and generally extends across and substantially obstructs the access opening in the closed position.
The present disclosure is best understood from the following detailed description when read with the accompanying Figures. It is emphasized that, in accordance with the standard practice in the industry, various features are not drawn to scale. In fact, the dimensions of the various features may be arbitrarily increased or reduced for clarity of discussion.
It is to be understood that the following disclosure describes several exemplary embodiments for implementing different features, structures, or functions of the invention. Exemplary embodiments of components, arrangements, and configurations are described below to simplify the present disclosure, however, these exemplary embodiments are provided merely as examples and are not intended to limit the scope of the invention. Additionally, the present disclosure may repeat reference numerals and/or letters in the various exemplary embodiments and across the Figures provided herein. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various exemplary embodiments and/or configurations discussed in the various Figures. Moreover, the formation of a first feature over or on a second feature in the description that follows may include embodiments in which the first and second features are formed in direct contact, and may also include embodiments in which additional features may be formed interposing the first and second features, such that the first and second features may not be in direct contact. Finally, the exemplary embodiments presented below may be combined in any combination of ways, i.e., any element from one exemplary embodiment may be used in any other exemplary embodiment, without departing from the scope of the disclosure.
Additionally, certain terms are used throughout the following description and claims to refer to particular components. As one skilled in the art will appreciate, various entities may refer to the same component by different names, and as such, the naming convention for the elements described herein is not intended to limit the scope of the invention, unless otherwise specifically defined herein. Further, the naming convention used herein is not intended to distinguish between components that differ in name but not function. Further, in the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to.” All numerical values in this disclosure may be exact or approximate values unless otherwise specifically stated. Accordingly, various embodiments of the disclosure may deviate from the numbers, values, and ranges disclosed herein without departing from the intended scope.
In an exemplary embodiment, the plurality of casing access openings 4 may be spaced circumferentially about the central axis AC, and spaced in generally equal angular increments that are generally axially aligned. However, the casing openings 4 may alternatively be unevenly angularly spaced and/or axially spaced apart, or the casing 1 may include only a single opening 4. In any of these cases, the cover member 12 is configured (e.g., sized and shaped, etc.) so as to extend across and completely cover all of the plurality of access openings 4 in the closed position PC. Further, each opening 4 may be generally rectangular and have two circumferential edges 4a, 4b and axial edges 4c, 4d, one circumferential edge 4a being located proximal to a casing section inner end 5a, as discussed in further detail below.
More specifically, the cover member 12 may include an annular body extending circumferentially about the central axis AC and may have opposing axial ends 12a, 12b, a central bore 15 extending between the two ends 12a, 12b, and an outer circumferential surface 16 extending axially between the ends 12a, 12b. The central bore 15 is sized to receive compressor components, such as a section of a main compressor shaft, shaft bearings, etc. (none shown), with clearance, such that the shaft is rotatable within the body and the body is axially displaceable along the shaft. The outer surface 16 is disposeable against section 2a of the casing inner circumferential surface(s) 2 adjacent to the access openings 4, such that the outer surface 16 generally seals against such adjacent surface section 2a of the casing 1, such sealing being assisted by radially-outward expansion of the body when subjected to high operating pressures inside the casing. Thereby, the cover member 12 seals or substantially prevents fluid flow through the one or more access openings 4.
Due to the fact that the cover outer surface 16 seals radially outwardly against the casing inner surface 2, the cover member 12 is located radially or diametrically inward of the casing 1 and is thus subjected to lesser stress (e.g., hoop shear) generated by high pressure fluid in the interior chamber CC in comparison with the casing 1. Also, the cover member 12 is at least partially supported by the casing sections against which the body outer surface 16 seals. For these reasons, the cover member 12 may be formed with a lesser thickness (tM) in comparison with the casing thickness (tC), as indicated in
Although the cover member 12 may include a one-piece annular body, it may alternatively be formed of a generally arcuate body (not illustrated) having at least a partially circumferential surface. In an alternative exemplary embodiment, the cover member 12 may be formed with a generally rectangular or other polygonal or complex-shaped tubular body shaped to match a corresponding shape of the casing inner surface 1.
Referring particularly to
Referring now to
More specifically, the retainer 22 may have opposing first and second axial ends 22a, 22b and may be located such that the first end 22a is located generally aligned with the outer circumferential edge 4a of each access opening 4. Further, the retainer 22 may be configured to retain the cover member 12 so as to limit axial movement of the member 12 between the open and closed positions PO and PC. Although not illustrated, an axial stop may be provided to limit the axial range of motion of the cover member 12. In one embodiment, the axial stop may include a radially outward projection on the cover member 12 or alternatively may include a radially inward projection on the retainer 22 or the inner surface of the casing section 5. In an exemplary embodiment, the projection could be a turned step or a radial bolt.
Specifically, the retainer 22 may have a central bore 23 configured to receive the cover member 12 such that at least a portion of the cover member 12 is or remains disposed within the central bore 23 in both the open and closed positions PO and PC, so that the cover member 12 and the retainer 22 may be always coupled together. Furthermore, the retainer 22 may also provide an internal bearing surface 24 against which the cover member outer surface 16 may slide during displacement between the open and closed positions PO, PC, as best shown in
In an exemplary embodiment of the present disclosure, the casing 1 may further have a generally radial shoulder surface 7 facing generally away from the access opening(s) 4 and the retainer body 22 may have a generally radial contact surface 26 disposed against the casing shoulder surface 7 so as to locate the coupled cover member 12 to move between the desired positions PO and PC. The shoulder surface 7 may also prevent axial displacement of the retainer 22 in a direction generally toward the access openings 4, thereby avoiding the potential for the retainer 22 from “dislodging” and displacing along, or in the direction of the axis Ac to a position where the one of more access openings 4 are obstructed.
Referring again to
In an exemplary embodiment, the first casing section 5 may include the one or more access openings 4 and the retainer member 22 may be disposed within the second casing section 6 generally adjacent to the casing section inner end 6a, with the cover member 12 being movable across the interface IC. That is, the cover member 12 may be disposed substantially within the second casing section 6 in the open position PO and may be at least partially disposed within the first casing section 5 in the closed position PC. Further, the casing first section 5 may include the shoulder surface 7, which may be spaced axially inwardly from the casing section first end 5a. As such, when the retainer 22 is positioned with the radial retainer contact surface 26 disposed against the casing shoulder surface 7, the retainer 22 may be partially disposed within the first casing section 5 and thus extend across the interface IC, thereby serving to increase the structural integrity of the casing 1 at the interface IC.
Referring particularly to
In an alternative exemplary embodiment, the cover member 12 may be manually moveable (i.e., when pressure in the chamber CC is at ambient pressure) between the open and closed positions PO, PC, such that the body 12 may be pushed or pulled by a compressor operator or maintenance person when it is desired to access the interior chamber CC through the openings 4. However, the closure device 10 may alternatively include an actuator or mechanism (not shown) configured to displace the cover member 12 between the two positions PO, PC, such as for example, a threaded rod and nut mechanism, a motor driven spindle, a hydraulic cylinder, etc.
Although the closure device 10 of the present disclosure is specifically described and depicted as being used in a high-pressure casing of a centrifugal compressor assembly, the closure device 10 may be used with any other high or low pressure casing assembly, such as for example, a low pressure centrifugal compressor, a reciprocating compressor or any other type of fluid machinery.
The foregoing has outlined features of several embodiments so that those skilled in the art may better understand the detailed description that follows. Those skilled in the art should appreciate that they may readily use the present disclosure as a basis for designing or modifying other processes and structures for carrying out the same purposes and/or achieving the same advantages of the embodiments introduced herein. Those skilled in the art should also realize that such equivalent constructions do not depart from the spirit and scope of the present disclosure, and that they may make various changes, substitutions and alterations herein without departing from the spirit and scope of the present disclosure.
