US2605045A - Sealing arrangement for closed centrifugal separators - Google Patents

Description

July 29, 1952 G. J. STREZYNSKI 2,605,045

SEALING ARRANGEMENT FOR CLOSED CENTRIFUGAL SEPARATORS Filed June 20, 1951 INVENTOR. Geo/ye f Lizf ezy/rski wad/7% 0% Patented July 29, 1 952 SEALING ARRANGEMENT FOR CLOSED CENTRIFUGAL SEPARATORS George J. Strezynski, Poughkeepsie, N. Y., as-

signor to The De Laval Separator Company,- New York, N. Y., a corporation of New Jersey Application June 20, 1951, Serial No. 232,517

14 Claims.

sages of the rotating separator bowl are coupled to relatively stationary feed or discharge pipes, respectively.

The prior art has offered numerous sealing arrangements for the inlet and discharge paths of closed centrifugal separators. Most of these arrangements are aimed at making the couplings from the stationary pipes, where they contact the rotating bowl, movable or flexible so as to partake of the lateral deviations and angular or tilting movements of the centrifugal bowl incident to its rotation. In some instances, the couplings include sealing collars or sleeves of rubber-like material secured to the stationary structure or pipes and closely surrounding central feed and discharge tubes of the rotating bowl. However, these rubber-like seals require rather frequent replacement due to wear and, moreover, are unsuitable when a component of the feed has a chemical action upon the rubber-like material and thus tends to destroy it. It has also been proposed to use concentric metal sealingrings engaging the bowl around central discharge passages and movable on bellows forming the flow connections to the stationary discharge pipes. This arrangement, however, is quite cumbersome. Furthermore, in both the rubber sleeve and the bellows arrangements, the sealing pressure against the bowl can be adjusted, if at all, only with considerable difiiculty.

The present invention has for its principal object the provision of an arrangement for sealing the inlet or discharge paths of closed centrifugal separators, which overcomes the above-mentioned difficulties with prior arrangements for this purpose.

The new sealing arrangement comprises a nonrotating sealing head having a member which terminates in an annular sealing surface complementary to and engaging a sealing surface of the separator bowl, a pivotal supporting member for the head preferably disposed centrally of the sealing surfaces and on the bowl axis, to permit the sealing head to follow the tilting'movements of the bowl in its rotation, and an adjustable connection between the pivotal support and the stationary structure of the centrifuge, for adjusting the pivotal support in a direction parallel to the bowl axis to regulate the pressure between the sealing surfaces. The annular inter-engaging sealing surfaces surround and seal a space through which a passage in the sealing head communicates with 'arpassage in the bowl, to provide a feed or discharge path between the bowl and a stationary pipe connected to the head. I :i

For a better understanding of the invention, reference may be had to the accompanying drawing in which the single figure is a vertical sectional view of a centrifugal separator showing the upper part of the separator bowl, thesealing head and the pivotal support mounted in operating position in accordance with the invention.

Referring to the drawing, the separator bowl, shown generally at I, is supported on a stationary structure for rotation about an axis. The particular mounting for the bowl and the details of the separating chamber in the bowl and the feed passage thereto; are not shown on the drawing, as they may be conventional. Theseparator bowl has a neck 5 surrounding the neck 6 of a top disc in the bowl, the annular members 5 and 6 being arranged concentrically with the bowl axis so as to define inner and outer discharge passages and 8, respectively, for discharging two separated, comp nents from the separating chamber. At the top of the bowl, the extremities of members 5 and 6 terminate in a common plane so as to form annular concentric surfaces 9 normal to the bowl axis.

The sealing head 2, which is non-rotating, comprises a casting ID of any suitable material and having outwardly extending discharge passages or conduits I I and I2. As will be evident from ,the drawing, passages II and I2 communicate with inner passage I and outer passage 8 of the bowl, respectively, whereby the separated materials from the bowl are conveyed separately through the head. Flexible piping I3 and I4 may be secured to the head around the discharge passages II and .I2, respectively-so as to convey the separated materials to the desired locations. The head has circular depending bottom members terminating in annular concentric sealing surfaces I5 surrounding the entrance ends of the passages I I and I2, respectively. The surfaces I5 are complementary to andengage corresponding sealing surfaces of thebowl I.

.In the embodiment'shown in the drawing, the sealing surfaces of the bowl are formed by annular discs I6, I! secured to the respective annular surfaces 9 at the top of the bowl. These discs are in sliding engagement with the sealing surfaces I5, respectively, of the head to provide a substantially liquid-tightl coupling of the passages l-I I and 8-I2. The material chosen for these discs will, of course. depend upon the mixture to be separated by the centrifuge. For example, when chloroform is one of the constituents to be separated, it is advisable to use Teflon discs, since rubber, the usual sealing medium, is attacked chemically by chloroform. Alternatively, a bi-metallic arrangement could be used wherein -stellite or a similar material is bonded to one pair of the surfaces 9 and I5 and another suitable metal is plated or secured to the other pair.

In order to maintain a sealing pressure between the surfaces |5-|6 and |5||, and support the sealing head laterally, a pivotal support 3 is provided for the sealing head 2. The pivotal support 3 engages in a central depression or recess l8 formed in the head and located on the rotation axis of the bowl. The pivotal support includes a cylindrical adjusting device l9 threaded at for insertion in the stationary structure, part of which is indicated at 4, the device l9 having a reduced stem portion 20. A hollow cup-or supporting member 2| has at the top a central opening loosely receiving the stem 26 and surrounded by a shoulder 22. The'lower portion of the cup tapers downward and fits into a downwardly tapered part of the recess Hi, the reduced end of the cup engaging the head at the bottom of the recess. However, the recess has a sharper taper than the cup, to provide a clearance around-the cup above its reduced end, as shown at 23. A biasing element is interposed between shoulder's 22-28 of the cup 2| and device l9, respectively, and is shown in the form of a compression spring coiled around the stem 20. The threaded part 20' and the spring 25 form an adjustable yielding connection between the pivotal supporting member 2| and the stationary structure 4, for regulating the pressure between the sealing surfaces l5-|6 and-lS-H.

A hand wheel 21, integral with adjusting device I9, is provided for imparting rotary motion thereto. As will be apparent from the drawing, the rotation of the device it increases or decreases the force applied by the biasing spring 25 and thus determines the pressure with which the cup or pivotal supporting member 2| will bear on the head 2 in depression l8. This arrangement' has the advantage that the actual pressure at the sealing surfaces |5|8 and l5-l1 may be'manually adjusted while the centrifuge is in operation, so that there is no need to stop the centrifuge for this purpose.

With the new construction, substantially no leakage will take place at the sealing surfaces |5-||i and'|5l'|. In order to prevent re-mixture of separated components due to any such leakage, and to recover the leakage, annular grooves 29 are formed in the sealing surfaces |5 of the head,'these grooves surrounding the entrance ends of the passages H and i2, respectively. The grooves 29 are interconnected by branch ducts 30 of an outlet duct 3|l in the sealing head 2. A fitting or nipple 3| secured to the body l0 serves to connect the duct 30* to a source of vacuum (not shown). In this way, any leakage between the sealing surfaces |5 -|6 and |5-|'| may be collected and returned to the centrifugal bowl in the feed stream.

The sealing head 2 may also be supported laterally by a cushioning mount 32 in the form of a rubber-like ring closely surrounding the circular depending portion of the head and interposed betweenthe latterand a part 33 of the stationary frame of the centrifuge. The cushion 4 32 permits some lateral movement of the head 2 and also tilting thereof with the bowl.

It will be understood from the drawing that the entrance or lower end of passage I2 in the sealing head is annular and overlies the outer annular passage 8 of the bowl, as shown at l2. This annular passage portion |2 surrounds the centrally located entrance end of the other passage in the head and merges around the latter passage and recess IS, with the main portion of the passage l2, as indicated by the dotted line l2". The entrance or lower end of passage overlies the central passage I of the bowl and merges with the main portion of passage through a lateral throat Il In the operation of the centrifuge, the rotat mg rings l6 and ll of the bowl can slide on the respective sealing surfaces iii of the head 2, to

accommodate lateral displacements of the bowl incident to its rotation. The sealing head itself can also undergo limited lateral movement against the cushion 32, by reason of the loose fit between the centering cup or pivotal support 2| and the fixed stem 29. The cushion 32 and the cup 2| allow the sealing head to tilt so as to follow the angular movements of the bowl during its rotation, while maintaining a tight engagement of the sealing surfaces l5|8 and |5|'|. This tilting of the head occurs about the lower portion of the stem 23 as a fulcrum and is yieldingly opposed by the spring 25, which tends to resist tilting of the cup relative to stem 20. The clearance 23 also allows some tilting of the head relative to the cup, in addition to facilitating a firm wedging action of the cup in the recess l8. The cup 2| could, of course, be made integral with the stem 28, in which case the head tilting would depend upon the clearance 23, but in either case the cup will act as a pivotal supporting member for the head. The sealing head 2 may be readily removed from the centrifuge, for cleaning, etc., by simply unscrewing the member l9 from the frame part i and disconnectingthe flexible pipes |3|4 from the head.

While the invention has been specifically described and illustrated in connection with the outlet of the centrifuge, it will be understood that the arrangement can also be applied to the inlet of the centrifuge with equal facility and with the same advantages.

I claim:

1. In a centrifuge having a stationary structure and a centrifugal bowl supported by said structure for rotation about an axis, the bowl having an annular sealing surface concentric with the axis and forming a passage communieating with the interior of the bowl, the combination of a sealing head having a member termimating in an annular surface in sealing engagement with said first surface and at least partly defining a passage in the head communicating with the bowl passage, a pivotal supporting member engaging the head and on which the head is tiltable relative to the stationary structure and an adjustable connection between the pivotal supporting member and said structure for regulating the sealing pressure between said surfaces.

2. A combination according to claim 1, in which said adjustable connection includes a yielding biasing element urging the pivotal supporting member against the head.

3 A combination according to claim 1, in which the pivotal supporting member is located centrally of said surfaces and on the bowl axis.

4. A combination according to claim 1, comprising also a yielding lateral support for the head at least partly surrounding the head and interposed between the head and the stationary structure.

5. A combination according to claim 1, in which the head has a recess disposed on the bowl axis and receiving the pivotal supporting member.

6. A combination according to claim 1, in which the head has a tapered recess, the pivotal supporting member being tapered and fitting into the tapered recess.

'7. A combination according to claim 1, in which the head has a tapered recess, the pivotal supporting member bein tapered and fitting into the tapered recess with a clearance around the enlarged portion of the tapered supporting member.

8, A combination according to claim 1, in which said connection includes an adjustment device on the stationary structure, the pivotal supporting member being itself pivotable on said device.

9. A combination according to claim 1, in which said connection includes an adjustment device on the stationary structure, the pivotal supporting member being itself pivotable on said device, and a yielding biasing element between the adjustment device and said supporting member for urging the pivotal supporting member against the head and opposing pivoting movement of said supporting member relative to the adjustment device.

10. In a centrifuge having a stationary structure and a centrifugal bowl supported by said structure for rotation about an axis, the bowl having an annular sealing surface concentric with the axis and forming a passage communicating with the interior of the bowl, the combination of a sealing head having a member terminating in an annular surface in sealing engagement with said first surface and at least partly defining a passage in the head communicating with the bowl passage, a pivotal supporting member engaging the head and on which the head is tiltable relative to the stationary structure, and a yielding connection between the pivotal supporting member and said structure, including a biasing element acting on the supporting member'to urge said surfaces together.

11. In a centrifuge having a stationary structure and a centrifugal bowl supported by said structure for rotation about an axis, the bowl having an annular sealing surface concentric with the axis and forming a passage communicating with the interior of the bowl, the combination of a sealing head having a member terminating in an annular surface in sealing engagement with said first surface and at least partly defining a passage in the head communicating with the bowl passage, and a pivotal supporting member connected to the stationary structure and engaging the head centrally of saidsurfaces and on the bowl axis, the head being tiltable on said supporting member relative to the stationary structure.

12. In a centrifuge having a stationary structure and a centrifugal bowl supported thereon for rotation about an axis, the bowl having annular sealing surfaces concentric with the axis and forming a central passage and also an outer annular passage communicating with the bowl interior, the combination of a sealing head having members terminating in annular concentric surfaces in sealing engagement with said bowl surfaces, respectively, and at least partly defining a central passage and an outer passage communicating, respectively, with said central passage and said outer passage of the bowl, said outer passage of the head surrounding said central passage of the head and merging into a main lateral passage in the head, said last central passage leading laterally away from said main lateral passage, a pivotal supporting member engaging the head above said central passage therein and on which the head is tiltable relative to the stationary structure, and a biasing connection between the supporting member and the stationary structure for urging the head against said bowl surfaces.

13. A combination according to claim 12, in which the head has an annular groove in each of said concentric sealing surfaces of the head, the head also having a vacuum passage communicating with said grooves.

14. A combination according to claim 12, in which the head has a central recess overlying the central passage therein and partly surrounded by said outer passage of the head, the pivotal supporting member engaging the head in said recess.

GEORGE J. STREZYNSKI.

REFERENCE S CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number

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