Sealing arrangement for axially split turbomachines

Abstract

An axially-split turbomachine comprising a casing comprised of a first casing portion and a second casing portion, forming a housing for a rotor arranged for rotation therein. The rotor comprises a shaft and at least one impeller mounted on the shaft. The casing comprises at least one shaft passageway through which the shaft extends from the interior of the casing towards the exterior of the casing. The sealing arrangement comprises a linear sealing member, extending between the first and the second casing portions. The sealing arrangement further comprises at least one sealing ring portion surrounding said at least one shaft passageway. The sealing ring portion and the linear sealing member form a continuous sealing body.

Claims

1. An axially-split turbomachine comprising: a casing comprising a first casing portion with a first contact surface and a second casing portion with a second contact surface; a sealing arrangement between the first casing portion and the second casing portion; a rotor arranged for rotation in the casing, the rotor comprising a shaft and at least one impeller mounted on the shaft; and at least one shaft passageway through the casing, the shaft extending through the shaft passageway, wherein the sealing arrangement comprises: a linear sealing member, extending between the first contact surface and the second contact surface, and at least one sealing ring portion surrounding the at least one shaft passageway, wherein the at least one sealing ring portion and the linear sealing member form a continuous sealing body.

2. The turbomachine of claim 1, further comprising a plurality of bolts connecting the first casing portion and the second casing portion to one another, wherein the linear sealing member is arranged between the rotor and the bolts.

3. The turbomachine of claim 1, further comprising at least one mechanical seal sleeve arranged in the at least one shaft passageway, the shaft extending through the mechanical seal sleeve, wherein the sealing ring portion is arranged around the mechanical seal sleeve.

4. The turbomachine of claim 3, wherein the mechanical seal sleeve comprises an external annular groove, partly housing the sealing ring portion.

5. The turbomachine of claim 3, wherein: the casing further comprises two shaft passageways, arranged at opposite ends of the casing, two end portions of the shaft extending through the two shaft passageways, a mechanical seal sleeve is arranged in each shaft passageway, between the casing and the shaft, the sealing arrangement comprises two sealing ring portions, each being arranged around a respective one of the mechanical seal sleeves, and the sealing ring portions are connected to the linear sealing member, forming a continuous sealing arrangement therewith, the continuous sealing arrangement surrounding the rotor and the two mechanical seal sleeves.

6. The turbomachine of claim 1, wherein the linear sealing member comprises two linear sealing portions connected to one another by at least one the sealing ring portion.

7. The turbomachine of claim 5, wherein each sealing ring portion is connected to the linear sealing member by respective T joints.

8. The turbomachine of claim 5, wherein each mechanical seal sleeve comprises an external annular groove, partly housing the respective sealing ring portion.

9. The turbomachine of claim 1, wherein: at least one of the first contact surface and the second contact surface comprises a groove, and the linear sealing member is partially housed in the groove.

10. The turbomachine of claim 1, wherein both the first contact surface and the second contact surface are provided with respective grooves, and the linear sealing member is at least partly housed in the grooves.

11. The turbomachine of claim 1, wherein the at least one shaft passageway comprises an annular groove, the at least one sealing ring portion being at least partly housed in the annular groove.

12. The turbomachine of claim 5, wherein each shaft passageway comprises a respective annular groove, and wherein the sealing ring portions are at least partly housed in the respective annular grooves.

13. The turbomachine of claim 2, further comprising at least one mechanical seal sleeve arranged in the at least one shaft passageway, the shaft extending through the mechanical seal sleeve, wherein the sealing ring portion is arranged around the mechanical seal sleeve.

14. The turbomachine of claim 13, wherein the mechanical seal sleeve comprises an external annular groove, partly housing the sealing ring portion.

15. The turbomachine of claim 14, wherein: the casing further comprises two shaft passageways, arranged at opposite ends of the casing, two end portions of the shaft extending through the two shaft passageways, a mechanical seal sleeve is arranged in each shaft passageway, between the casing and the shaft, the sealing arrangement comprises two sealing ring portions, each being arranged around a respective one of the mechanical seal sleeves, and the sealing ring portions are connected to the linear sealing member, forming a continuous sealing arrangement therewith, the continuous sealing arrangement surrounding the rotor and the two mechanical seal sleeves.

16. The turbomachine of claim 4, wherein: the casing further comprises two shaft passageways, arranged at opposite ends of the casing, two end portions of the shaft extending through the two shaft passageways, a mechanical seal sleeve is arranged in each shaft passageway, between the casing and the shaft, the sealing arrangement comprises two sealing ring portions, each being arranged around a respective one of the mechanical seal sleeves, and the sealing ring portions are connected to the linear sealing member, forming a continuous sealing arrangement therewith, the continuous sealing arrangement surrounding the rotor and the two mechanical seal sleeves.

17. The turbomachine of claim 6, wherein each sealing ring portion is connected to the linear sealing member by respective T joints.

18. The turbomachine of claim 6, wherein each mechanical seal sleeve comprises an external annular groove, partly housing the respective sealing ring portion.

19. The turbomachine of claim 7, wherein each mechanical seal sleeve comprises an external annular groove, partly housing the respective sealing ring portion.

20. The turbomachine of claim 6, wherein each shaft passageway comprises a respective annular groove, and wherein the sealing ring portions are at least partly housed in the respective annular grooves.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) A more complete appreciation of the disclosed embodiments of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying drawings, wherein:

(2) FIG. 1 illustrates a schematic front view of a centrifugal pump;

(3) FIG. 2 illustrates a sectional view according to II-II of FIG. 1, with portion removed;

(4) FIG. 3 illustrates an enlargement of one of the shaft passageways provided in the casing of the pump of FIGS. 1 and 2;

(5) FIG. 4 illustrates an enlarged perspective view of the shaft passageway with the mechanical seal sleeve removed;

(6) FIG. 5 illustrates a perspective view of a portion of the sealing arrangement according to one embodiment of the present disclosure;

(7) FIG. 6 illustrates an enlarged schematic cross section of the linear sealing member arranged between the two contact surfaces of the casing portions.

DETAILED DESCRIPTION

(8) The following detailed description of the exemplary embodiments refers to the accompanying drawings. The same reference numbers in different drawings identify the same or similar elements. Additionally, the drawings are not necessarily drawn to scale. Also, the following detailed description does not limit the invention. Instead, the scope of the invention is defined by the appended claims.

(9) Reference throughout the specification to “one embodiment” or “an embodiment” or “some embodiments” means that the particular feature, structure or characteristic described in connection with an embodiment is included in at least one embodiment of the subject matter disclosed. Thus, the appearance of the phrase “in one embodiment” or “in an embodiment” or “in some embodiments” in various places throughout the specification is not necessarily referring to the same embodiment(s). Further, the particular features, structures or characteristics may be combined in any suitable manner in one or more embodiments.

(10) As will become apparent from the following detailed description of embodiments of the subject matter to which the present disclosure refers, an axially-split turbomachine is provided, comprising a casing comprised of a first casing portion and a second casing portion, forming a housing for a rotor arranged for rotation therein. The rotor comprises a shaft and at least one impeller mounted on the shaft. The casing comprises at least one shaft passageway, through which the shaft extends from the interior of the casing towards the exterior of the casing. The sealing arrangement comprises a linear sealing member, extending between the first and the second casing portions. The sealing arrangement further comprises at least one sealing ring portion surrounding said at least one shaft passageway. The sealing ring portion and the linear sealing member form a continuous sealing body.

(11) FIG. 1 illustrates a schematic front view of a centrifugal pump 1. The centrifugal pump comprises a casing 3 having a first casing portion 5 and a second casing portion 7. The two casing portions 5 and 7 match along an axial plane P-P, containing the rotation axis A-A of the rotor of the pump 1.

(12) Each casing portion 5, 7 comprises a respective contact surface. Reference number 5A designates the contact surface of the first casing portion 5 and reference number 7A indicates the contact surface of the second casing portion 7.

(13) The two casing portions 5 and 7 are connected to one another by means of a plurality of bolts 9 and nuts. The bolts 9 are pre-loaded and generate a contact pressure between the two contact surfaces 5A, 7A and a sealing arrangement provided there between. The sealing arrangement will be described in greater detail later on.

(14) The bolts 9 extend through holes 11 (see FIG. 2) provided in the two casing portions 5 and 7. The bolts 9 and respective holes 11 are distributed on both sides of a rotor housing 13 formed by the two casing portions 5, 7. The rotor housing 13 houses a rotor 15. In some embodiments, the rotor 15 comprises a shaft 17 and a plurality of impellers 19 keyed on the shaft 17 and rotating therewith.

(15) According to some embodiments, both opposite terminal or end portions of the shaft 17 extend through respective first and second passageways 21, 23 formed in the casing.

(16) Mechanical seal sleeves 25 and 27 are arranged in the two passageways 21 and 23. The terminal shaft portions extend through the respective mechanical seal sleeves and are supported by respective bearings 29, 31 arranged in opposite end portions of the casing 3.

(17) A sealing arrangement labeled 33 as a whole is arranged between the two opposite contact surfaces 7A, 5A of the two casing portions 7 and 5. The sealing arrangement 33 can be comprised of a first linear sealing member 35 and two sealing ring portions 37, 39.

(18) In some embodiments the linear sealing member 35 has a circular cross-section. In other embodiments the linear sealing member can have an elliptical cross-section. In yet further embodiments the linear sealing member can have a polygonal cross-section.

(19) The ring sealing portions 37, 39 can have a cross section similar to or identical to the cross section of the linear sealing member 35.

(20) The linear sealing member 35 can be comprised of two linear sealing portions provided on opposite sides of the rotor housing 13. Each linear sealing portion extends between the rotor housing 13 and the bolts 9 and respective holes 11. The two sealing ring portions are arranged between the two linear sealing portions of the linear sealing member and form a continuous sealing arrangement therewith.

(21) The linear sealing member 35 fluidly separates the rotor housing 13 from the bolts 9 preventing leakage from the interior of the pump towards the bolts.

(22) In some embodiments the two contact surfaces 5A, 7A can be planar and the linear sealing member 35 can be simply placed between the two facing planar surfaces 5A, 7A. In other embodiments at least one of the two opposing contact surfaces 5A, 7A can be provided with a linear groove at least partly housing the linear sealing member 35. As shown particularly in FIG. 4, in this embodiment the contact surface 7A formed by the second casing portion 7 is provided with a groove 41 extending between the rotor housing 13 and the holes 11 through which the bolts 9 extend. The linear sealing member 35 is partly housed in the groove 41.

(23) A similar groove can be provided on the opposing contact surface 5A.

(24) The enlargement of FIG. 6 illustrates a local cross-section according to a plane orthogonal to the planar contact surfaces 5A, 7A. FIG. 6 illustrates the groove 41 provided in the contact surface 7A and an opposing groove 43 provided in the contact surface 5A. As can be appreciated from FIG. 6, in this embodiment the linear sealing member 35 has a substantially circular cross-section. The diameter of the linear sealing member 35 and the depth of the two grooves 41, 43 are dimensioned so that when the casing portions are placed one on top of the other, the bolts 9 are tightened, the two casing portions 5, 7 are in contact with one another along the contact surfaces 5A, 7A and/or the linear sealing member 35 is compressed therebetween. By tightening the bolts, the linear sealing member 35 will be compressed and elastically deformed in the seat formed by the grooves 41, 43. A high contact pressure will be established between the linear sealing member 35 and the surfaces of grooves 41, 43. Since the surface of contact between the sealing member 35 and the casings portions 5, 7 is small, a high contact pressure between the sealing member 35 and the casing portions can be achieved with a small tensile stress along the bolts 9.

(25) In other embodiments a groove can be provided only in one of the two opposing contact surfaces 5A, 7A, the other one of the two surfaces being planar. In yet further embodiments, both contact surfaces 5A, 7A can be planar, and the linear sealing member 35 can be positioned there between. Using a groove 41 or 43 or both makes positioning of the sealing arrangement and assembling the turbomachine casing easier.

(26) As can best be seen in FIG. 2, the linear sealing member 35 forms a single body with the two sealing ring portions 37, 39 surrounding the mechanical seal sleeves 25 and 27.

(27) The enlargement of FIG. 5 shows one of the two sealing ring portions 37, 39 and the connection thereof with the adjacent portions of the linear sealing member 35. The components 35, 37/39 are joined at respective T-shaped joints shown at 47.

(28) Each sealing ring portion 37, 39 surrounds the respective mechanical seal sleeves 25 and 27 and is arranged between the respective mechanical seal sleeve and the inner surface of the respective passageway 21, 23, formed by the two casing portions 5 and 7.

(29) In some embodiments the outer surface of the mechanical seal sleeve 25, 27 can be provided with an annular groove 49 (see FIG. 3). The sealing ring portion 37/39 is partly housed in the respective annular groove 49 of the corresponding mechanical seal sleeve 25, 27.

(30) In some embodiments the groove 49 can be omitted. In this case the sealing ring portion 37, 39 will simply be mounted on the cylindrical outer surface of the respective mechanical seal sleeve.

(31) In some embodiments the inner surfaces of the two casing portions 5 and 7 forming the respective passageways 21 and 23 can be provide with respective semi-annular grooves 51 (see FIG. 4). The sealing ring portions 37, 39 are in this case partly housed in the annular groove which is formed by the two semi-annular grooves 51 upon mounting of the two casing portions 5 and 7 one on top of the other. In other embodiments, the inner surface of the passageway 21, 23 can be smooth, i.e. devoid of the semi-annular grooves 51. In this case the sealing ring portion 37, 39 will be simply mounted in contact with the cylindrical surface of the passageway.

(32) When one, the other or both the annular and semi-annular grooves 49, 51 are provided, the depth of the grooves and the cross-sectional dimensions of the sealing ring portions 37, 39 are selected so that the sealing ring portions 37, 39 are squeezed and compressed upon locking of the bolts 9, thus providing a sealing effect around the mechanical seal sleeve 25, 27. A concentrated contact pressure is generated on the limited surface of contact between the two sealing ring portions 37, 39 and the mechanical components in contact therewith, namely the outer surface of the mechanical seal sleeves 25, 27 and the inner surface of the passageways 21, 23.

(33) As can best be appreciated from FIG. 4, the semi-annular grooves 41 (if present) are aligned with the corresponding grooves 41 and 43 provided on the contact surfaces 7A, 5A respectively. To prevent damages of the sealing arrangements at the joining area where the linear sealing member 35 is connected to the respective sealing ring portion 35, 37, the grooves 41, 43 and the semi-annular grooves 51 of the passageways are joined to one another along a rounded edge 55, thus avoiding damages and scraps of the sealing member during case assembling

(34) In some embodiments the two sealing portions 37, 39 can be manufactured separately from the two portions of the linear sealing member 35. The four components, namely the two portions of the linear sealing member 35 and the two sealing ring portions 37, 39 can be connected to one another in a subsequent manufacturing step, for example by gluing, welding, or in any other suitable manner. This greatly simplifies the manufacturing process and prevents the need for a complex mold, which would be required for manufacturing the sealing arrangement 35, 37, 39 as a single monolithic component. This option, however, is not excluded.

(35) The sealing arrangement 35, 37, 39 provides a continuous sealing around the entire inner housing 13 of the centrifugal pump. The linear sealing member 35 provides a radial sealing between the bolts 9 and the inner housing 13 where the rotor 15 is arranged, the linear sealing member 35 developing between the holes 11 through which the bolts 9 extend and the volutes formed in the casing 3. The two sealing portions 37, 39 provide an axial sealing effect at the opposing ends of the shaft 17, around the mechanical seal sleeves 25, 27.

(36) The small surface of contact between the sealing arrangement and the mechanical parts of the turbomachine results in a limited pre-load required to achieve a sufficient and reliable sealing.

(37) While the disclosed embodiments of the subject matter described herein have been shown in the drawings and fully described above with particularity and detail in connection with several exemplary embodiments, it will be apparent to those of ordinary skill in the art that many modifications, changes, and omissions are possible without materially departing from the novel teachings, the principles and concepts set forth herein, and advantages of the subject matter recited in the appended claims. Hence, the proper scope of the disclosed innovations should be determined only by the broadest interpretation of the appended claims so as to encompass all such modifications, changes, and omissions. In addition, the order or sequence of any process or method steps may be varied or re-sequenced according to alternative embodiments.