TITLE OF THE INVENTION Rotary Separator Drum Seal

The present invention relates to fluid machinery, and more particularly to seal assemblies for rotary fluid separators.

Rotary separators for separating solids from fluids, liquids from gases, or/and gases or liquids of varying density are known. Such rotary separators typically include a rotatable tubular body or "drum" having a central bore with inlet and outlet ends. With this structure, fluid flow enters the inlet end and passes through the bore, such that heavier fluids (e.g., liquids) are directed outwardly onto a drum inner surface, and generally pass through openings therethrough for collection, while the lighter fluids (e.g., gas) pass through an outlet end of the drum. Typically, fluid flow out of the drum outlet is directed into one or more passages, such as an inlet of a compressor or an outlet pipe of a "stand alone" separator device. To prevent inflow of inlet fluids to the outlet flow, and thus preventing remixing of separated fluids (e.g., liquids), the drum outlet end is normally sealed against a static member located adjacent to the drum. Such a static member may be a partition wall (e.g., diaphragm) in a fluid machine, an inlet wall of a compressor, a casing wall of a stand alone separator, etc. As there must be some clearance between the drum end and the static member to allow free rotation of the drum, the seal between the drum and static member is typically non-contact. However, with previously known seal designs, there is a risk of undesired separated fluids (e.g., liquids) from passing through the clearance space and back into the outlet fluid stream.

SUMMARY OF THE INVENTION

In one aspect, the present invention is a seal assembly for a fluid machine including a casing and a shaft disposed within the casing so as to be rotatable about a central axis. The seal assembly comprises a static member generally fixedly disposed within the casing and having an end surface and a rotatable member coupled with the shaft and spaced axially from the static member. The rotatable member has an axial end with a generally radial end surface extending circumferentially about the shaft axis, the rotatable member end surface being located adjacent to and facing the static member end surface such that a clearance space is defined generally between the two end surfaces. The rotatable member further has a plurality of openings extending generally axially inwardly from the rotatable

member end surface and spaced circumferentially about the shaft axis such that land surface sections are defined on the end surface. The land surface sections or/and the openings are configured to at least generally prevent fluid flow radially inwardly through the clearance space. In another aspect, the present invention is a compressor comprising a casing, a shaft disposed within the casing so as to be rotatable about a central axis, and at least one impeller mounted on the shaft and disposed within the casing, the at least one impeller having an inlet and an outlet. A static member is generally fixedly disposed within the casing and has an end surface and a separator member coupled with the shaft and spaced axially from the static member. The separator member has an axial end with a generally radial end surface extending circumferentially about the shaft axis, the separator member end surface being located adjacent to and facing the static member end surface such that a clearance space is defined generally between the two end surfaces. The compressor further includes at least one and preferably all of the following "sealing" elements: 1) a plurality of openings extending generally axially inwardly from the separator member end surface and spaced circumferentially about the shaft axis such that land surface sections are defined on the end surface, at least one of the land surface sections and the openings being configured to at least generally prevent fluid flow through the clearance space; 2) at least one outer generally annular ridge extending from an inner circumferential surface of the static member and toward an outer circumferential surface of the separator member; 3) at least one inner generally annular ridge extending from an outer circumferential surface of the static member and toward an inner circumferential surface of the separator member; 4) inner and outer generally annular wall sections each extending generally axially from the static member axial end and toward the separator member, the inner and outer annular wall sections defining a generally annular pocket configured to receive a portion of the separator outlet end; and 5) a generally annular deflector portion extending generally axially and generally radially outwardly from the axial end and extending circumferentially about the shaft central axis, the deflector portion being spaced radially outwardly from the static member end surface and having an angled surface facing generally toward the central axis and away from the static member end surface.

In a further aspect, the present invention is a seal assembly for a fluid machine including a casing and a shaft disposed within the casing so as to be rotatable about a central axis. The seal assembly includes a static member generally fixedly disposed within the casing and having an axial end with an end surface and inner and outer generally

annular wall sections each extending generally axially from the static member axial end and toward the separator member. The end surface extends between the inner and outer annular wall sections and the two wall sections defining a generally annular pocket. A rotatable member is coupled with the shaft and is spaced axially from the static member and has inner and outer circumferential surfaces and axial end with a generally radial end surface extending circumferentially about the shaft axis. The rotatable member end surface being located adjacent to and facing the static member end surface such that a clearance space is defined generally between the two end surfaces and a portion of the rotatable member axial end is disposed within the static member pocket. Further, the static member also includes at least one inner generally annular ridge extending radially outwardly from the static member inner annular wall section toward the rotatable member inner surface, the inner annular ridge being configured to provide a labyrinth seal for at least generally inhibiting fluid flow between the static member inner annular wall section and the rotatable member inner surface. Also, the static member includes at least one outer generally annular ridge extending radially inwardly from the static member outer annular wall section toward the rotatable member outer surface, the outer annular ridge being configured to provide a labyrinth seal for at least generally inhibiting fluid flow between the static member outer annular wall section and the rotatable member outer surface.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS The foregoing summary, as well as the detailed description of the preferred embodiments of the present invention, will be better understood when read in conjunction with the appended drawings. For the purpose of illustrating the invention, there is shown in the drawings, which are diagrammatic, embodiments that are presently preferred. It should be understood, however, that the present invention is not limited to the precise arrangements and instrumentalities shown. In the drawings:

Fig. 1 is an axial cross-sectional view of a combination separator and compressor device including a seal and fluid handling assembly in accordance with the present invention;

Fig. 2 is an enlarged, broken-away axial cross-sectional view of an upper half of the separator/compressor, showing a more detailed view of the separator and compressor; Fig. 3 is a more enlarged, broken-away axial cross-sectional view of the separator and a static member forming a compressor inlet;

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Fig. 4 is a greatly enlarged, broken-away axial cross-sectional view of an interface between the separator member and the static member;

Fig. 5 is an even more greatly enlarged, broken away view of a portion of the separator member and the static member, shown spaced apart to better illustrate portions of the seal;

Fig. 6 is a broken-away, side plan view of a separator end surface taken at line 6-6 of Fig. 5;

Fig. 7 is a very greatly enlarged, broken-away axial cross-sectional view of the seal at the interface between the separator and static member; and Fig. 8 is a broken-away, perspective view of portions of the separator member and the static member.

DETAILED DESCRIPTION OF THE INVENTION Certain terminology is used in the following description for convenience only and is not limiting. The words "right", left", "lower", "upper", "upward", "down" and

"downward" designate directions in the drawings to which reference is made. The words "inner", "inwardly" and "outer", "outwardly" refer to directions toward and away from, respectively, a designated centerline or a geometric center of an element being described, the particular meaning being readily apparent from the context of the description. Further, as used herein, the word "connected" is intended to include direct connections between two members without any other members interposed therebetween and indirect connections between members in which one or more other members are interposed therebetween. The terminology includes the words specifically mentioned above, derivatives thereof, and words of similar import. Referring now to the drawings in detail, wherein like numbers are used to indicate like elements throughout, there is shown in Figs. 1-8 a seal assembly 10 for a fluid machine 1, preferably a compressor 2 with a rotatable separator 3 located at the inlet 4a of a first (or sole) compression stage 4, as described below. The fluid machine 1 preferably includes a casing 5 and a shaft 6 disposed at least partially within the casing 5 so as be rotatable about a central axis 6a. The seal assembly 12 basically comprises a rotatable member 12, a static member 16, and one or more "sealing elements" formed in or on the static member 12 or the static member 16, as described below. More specifically, the static member 16 is generally fixedly disposed within the casing 5 and has an axial end 18 with an end surface 19 extending circumferentially about the axis 6a. The rotatable

member 12 is coupled with the shaft 6 and spaced axially from the static member 12, the rotatable member 12 having an axial end 14 with a generally radial end surface 15 extending about the axis 6a and located generally adjacent to and facing the static member end surface 19 such that a clearance space Sc is defined between the two surfaces 15, 19. Further, the seal assembly 10 includes at least one and preferably all of the following "sealing" elements/components:

1) a plurality of openings 20 in the end surface 15 of the rotatable member 12 forming labyrinth teeth for sealing the clearance space Sc; 2) one or more outer annular ridges 34 extending inwardly from an inner circumferential surface 29 of the static member 16 toward an outer surface 58b of the rotatable member 12, or/and one or more inner annular ridges 32 extending outwardly from an outer circumferential surface 27 of the static member 16 and toward an inner surface 58a of the static member 12, so as to form labyrinth seal between the two surfaces 29/58b or/and 31/58a;

3) a "pocket" 30 formed in the static member axial end 18 for receiving a portion 58 of the rotatable member axial end 16; and

4) an annular deflector wall 36 extending from the static member axial end 18 and spaced radially outwardly from the rotatable member for deflecting flow from the interface Is between the rotatable and static member end surfaces 15, 19.

Although preferably including all four of the above elements or components, the seal assembly 12 of the present invention may include any one or more of these elements/components, e.g., only the rotating "radial" labyrinth teeth formed by the rotatable member end openings 20.

Referring to Figs. 4-7, the plurality of openings 20 of the rotatable member 12 are formed in the axial end 14 such that each opening 20 extends generally axially into the rotatable member 12 from the member radial end surface 15 and spaced circumferentially about the end surface 15. Preferably, each one of the plurality of openings 20 of the rotatable member 12 is formed as a generally circular hole 23 having an enclosed inner end 23, but may have any other appropriate shape (e.g., elliptical) or/ and may be formed as a "through hole" (no alternatives shown). Further, the openings 20 are preferably arranged in at least first and second generally circular rows of openings 20, most preferably three rows Ri, R ₂ , R ₃ (see Fig. 6), such that the openings 20 "occupy" a

substantial portion of the member end surface 15. The second row R ₃ of openings 20 are spaced radially outwardly from the first row Ri of openings 20 and the third row R ₃ of openings 20 is spaced radially outwardly from both the first and second rows Ri, R ₂ . Preferably, each opening 20 in the first row Ri of openings 20 is generally radially aligned with a separate one of the openings 20 of the second row Ri and a separate opening 20 of the third row R ₃ . However, the openings 20 may be alternatively arranged such that the openings 20 in the two or more rows R _# are radially non-aligned or "staggered".

Further, the openings 20 define a plurality of land sections or "lands" 22 between the openings 20 on the end surface 15, which are slidably displaceable generally against the static member end surface 19 during rotation of the rotatable member 12. The lands 22 and/or the openings 20 are configured to at least generally prevent fluid flow through the clearance space Cs between the rotatable and static members 12, 16, respectively. Specifically, the lands 22 and openings 20 are configured to provide a "radial" labyrinth seal 21 between the rotatable member end surface 15 and the static member end surface 19, in which the lands 22 function as "labyrinth teeth". In other words, the outer ends 22a of each land or tooth 22 is located in close proximity to the static member end surface 19, so as to limit the space available for flow between the facing end surfaces 17, 19, and the openings 20 act as chambers for "capturing" any fluid penetrating past the lands/teeth 22 for subsequent ejection by centrifugal forces generated by the rotation of the member 12. Specifically, each one of the plurality of openings 20 is configured to collect liquid directed into the opening 20 and to subsequently direct collected liquid out of the opening 20 and radially outwardly away from the central axis 6a during rotation of the rotatable member 12. That is, at least a portion of any liquid entering between the lands 22 and the static member end surface 19 tends to be pulled into the openings 20 during rotation of the rotatable member 12, both preventing the particular liquid portion from flowing through the clearance space Sc (Fig. 7) and acting as a barrier against further liquid flow through the space Sc-

As best shown in Fig. 6, the lands 22 include both radially-extending or radial portions 24 and circumferentially-extending or circumferential portions 25. The land radial portions 24 are each configured to direct or "sling" liquid contacting the land radial portion 24 radially outwardly from the central axis 6a during rotation of the rotatable member 12. Also, the land circumferential portions 25 are configured to direct liquid contacting the circumferential portions 25 either towards a proximal radial portion 24 for

subsequent "slinging" out of the clearance space Sc, or into at least one of the plurality of openings 20 so as to generally prevent liquid flow through the clearance space Sc.

Thus, centrifugal forces act on liquid captured in the openings 20 or disposed on the lands 22 such that the liquid is directed radially outwardly away from central axis 22. Specifically, centrifugal force causes the land radial portions 24 to sling liquid located therein radially outwardly, as described above, and also tending to push liquid in the openings 20 onto the lands 22. That is, centrifugal force causes liquid located in the openings 20 to flow in a radially outward direction out of the opening 20 and onto adjacent land portions 24 or 25 for subsequent slinging therefrom. Referring now to Figs. 4, 5 and 7, the seal assembly 10 preferably further comprises a first, inner annular wall section 26 and a second, outer generally annular wall section 28 spaced radially outwardly from the first annular wall section 26, each annular wall section 26, 28 extending generally axially from the static member axial end 18 and generally toward the rotatable member 12. The inner wall section 26 has an outer circumferential surface 27 and the outer annular wall section 28 has an inner circumferential surface 29, the inner and outer wall surfaces 27, 29 defining a generally annular pocket 30 (Fig. 5) sized to receive a portion 58 of the rotatable member axial end 14, as described below. Preferably, the seal assembly 10 further comprises at least one generally annular ridge 32 extending outwardly from the inner wall section 26 and at least one and preferably a plurality of generally annular inner ridges 34 extending inwardly from the outer wall section 26, each ridge 32, 34 extending circumferentially about the central axis 6a. The inner and outer annular ridges 32, 34 each extend toward the rotatable member portion 58 located in the pocket 30 and are configured to provide inner and outer "circumferential" labyrinth seals 33, 35, respectively, between the annular wall sections 26, 28 and the rotatable member 12.

More specifically, the inner ridge(s) 32 are configured to provide an inner circumferential labyrinth seal 33 to generally prevent or at least inhibit flow through an inner annular clearance space SAci (Fig. 7) between the inner annular wall section 26 and an inner circumferential surface 58a of the rotatable member 12. Further, the outer ridge(s) 34 are configured to provide an outer circumferential labyrinth seal 35 preventing/inhibiting flow through an outer annular clearance space SAco (Fig. 7) between the outer annular wall section 28 and an outer circumferential surface 58b of the rotatable member 12.

Although depicted in the drawings as having labyrinth ridges or teeth 32, 34 formed by providing annular grooves in the inner and outer annular walls 26, 28 (e.g., by cutting, milling, etc.), the ridges/teeth 32, 34 may alternatively be formed by providing annular projections extending outwardly from remaining wall sections (e.g., casting, molding, etc.) or in any other appropriate manner. Further, although the drawings depict the inner ridge 32 as being of generally uniform size and having generally V-shaped axial cross-sections and the outer ridges as having generally rectangular axial cross-sections (see, e.g., Fig. 5), the ridges/teeth 32, 34 may have any appropriate shape, such as for example, generally semi-circular, or may be "staggered" or unevenly spaced. Referring to Figs. 3-5, the seal assembly 10 also preferably comprises a deflector portion or "deflector" 36 extending axially and radially outwardly from the static member outer wall section 28. The deflector 36 is generally annular and extends generally axially and generally radially outwardly from the static member axial end 18, and extends circumferentially about the shaft central axis 6a. The deflector 36 is spaced radially outwardly from the static member end surface 19 and has an angled surface 38 facing generally toward the central axis 6a and away from the static member end surface 19. With this structure, the deflector surface 38 is configured to generally deflect any liquid contacting the surface 38 in a direction generally away from the rotatable member axial end 30. As such, the deflector 36 functions to at least generally inhibit or prevent liquid located externally of the rotatable member 12 from entering the clearance space Sc.

Preferably, the deflector 36 also has an outer angled surface 39 facing generally radially outwardly and away from the central axis 6a, which preferably has a slope (not indicated) that is less "steep" as compared to the inner angled surface 38. The outer angled surface 39 acts to deflect the main fluid stream flowing externally of the rotatable member 12 generally upward and away from the interface Is between the rotatable and static members 12, 14.

As discussed above, although the seal assembly 10 preferably includes all of the above-noted components, specifically the axial holes 20 and lands 22 providing a radial labyrinth seal 21, the inner and outer annular walls with annular ridges forming labyrinth seals, and the outer deflector 36, the seal assembly 10 of the present invention may include any one or more of such components. That is, a seal assembly 10 in accordance with the present invention may only include a radial labyrinth seal 21, only the inner and outer circumferential labyrinth seals 33, 35, just the deflector 36, etc., or any combination of two of these components (e.g., radial labyrinth seal 21 and inner circumferential seal 33, etc.)

Referring to Figs. 1 and 2, the rotatable member 12 and the static member 16 form a fluid handling assembly 40 for the fluid machine 1, most preferably portions of a rotary separator 3 and an adjacent "transition" member 44 between the rotary separator 3 and a subsequent device or component (e.g., a compressor impeller, an outlet pipe, etc.). As discussed above, the fluid machine 1 is preferably a compressor 2 that includes one or more compression stages 4, each stage 4 including an impeller 8 mounted to the shaft 6 and each impeller 8 having an inlet 8a and an outlet 8b. The casing 5 has an interior chamber Cc and the rotor shaft 6 extends generally centrally and longitudinally through the chamber Cc. However, the fluid machine 1 may alternatively be any other appropriate fluid handling device, such as for example, a "stand alone" rotary separator, etc., in which a rotatable member interfaces or seals against a static member.

Referring to Figs. 2-5, with the preferred application described above, the rotatable member 12 is preferably at least part of a rotary separator 3 including a generally tubular body 50 mounted to the rotor shaft 6 so as to be rotatable therewith. The tubular body 50 has opposing inlet and outlet ends 52, 54, the outlet end 54 providing the axial end 14 sealing against the static member 16, and a central bore 56 extending between the two ends 52, 54. The tubular body 50 has a central axis 51, which is generally collinear with the machine central axis 6a, and inner and outer circumferential surfaces 53A, 53B, respectively, extending circumferential Iy about the axis 51. Most preferably, the tubular body or "drum" 50 includes two axially spaced apart, connected body sections 5 IA, 5 IB; specifically a first, generally circular cylindrical portion 51 A providing the inlet end 52 and a second, generally conical section 5 IB providing the outlet end 54. The drum conical section 51 B has an inner diameter (not indicated) that tapers from a greater value proximal to the cylindrical section 52 to a lesser value generally proximal to the outlet end 54, such that separated liquid is forced in a direction toward the inlet end 52. As best shown in Fig. 3, the drum conical section 5 IB further has a circumferential collection groove 55 and a plurality of liquid outlet through holes 57 extending radially outwardly from the groove 55, through which separated liquid passes for subsequent collection. Further, as indicated in Fig. 5, the body conical section 5 IB also includes a radially-outwardly extending, generally circular portion 58 at the outlet end 54, as discussed above, which provides substantially circular, inner and outer surface sections 58a, 58b against which seals the one or more inner and outer annular ridges 32, 34, respectively.

Referring to Figs. 2-5, the static member 16 is preferably at least a portion of an impeller inlet wall 60 fixedly disposed within the casing 5, but may alternatively be a

partition wall or "diaphragm" located between the separator outlet end 54 and an impeller inlet wall (structure not shown). The inlet wall 60 preferably includes a generally conical ring-like body 62 with first and second axial ends 64, 65, respectively: The first end 64 provides the static member axial end 18 as described above, and the second end 65 is connected with a diaphragm wall 70 that partially defines fluid passages 72 for the first compression stage 4 (see Fig. 2). The static inlet wall 62 includes at least one passage 66 extending inwardly from the static member axial end 18, preferably a central through hole or bore 68 extending completely through the body 62 between the body ends 64, 65. Further, the static member bore 68 is fluidly coupled with the separator bore 56 such that fluid flow F through the separator bore 56 enters the at least one static member passage 66/bore 68 for subsequent handling, preferably compression within the first compression stage 4. Further, a de-swirl vane member 76 is preferably mounted within the central static member bore 68, which functions to de-swirl and circumferentially distribute fluid flow entering the first compression stage 4, as best shown in Figs. 3 and 8. The de-swirl vane member 76 includes a plurality of angled vanes 80 which divide the bore 68 into a plurality of separate flow passages 82 fluidly connected with the inlet 8a of the first or single impeller 8.

Referring to Figs. 2 and 5, with the preferred compressor inlet application described above, the seal assembly 10 also preferably includes at least one and preferably a plurality of fluid passages 78 (only one shown) extending at least partially axially through the static member 16 and spaced circumferentially about the axis 6a. Each fluid passage 78 has an inlet 78a fluidly coupled with an impeller outlet and an outlet 78b extending through the static member end surface 19. As such, each fluid passage 78 is configured to direct fluid from the associated impeller 8 generally into the clearance space Sc- Specifically, each passage 78 is configured to direct a "purge" flow f _P of compressed gas, preferably drawn from the impeller outlet 8b of the first compression stage 4, into the clearance space Sc- The purge flow fp from the passages 78 create a positive pressure at the interface Is between the rotatable member 12 and the static member 16, which forces liquids away from the entrance(s) to the seal area to thereby prevent "ingestion" of liquids within the seal assembly 10.

It will be appreciated by those skilled in the art that changes could be made to the embodiments described above without departing from the broad inventive concept thereof. It is understood, therefore, that this invention is not limited to the particular embodiments

disclosed, but it is intended to cover modifications within the spirit and scope of the present invention as generally defined in the appended claims.