GB2097072A - Mounting a sealing element - Google Patents

Mounting a sealing element Download PDF

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Publication number
GB2097072A
GB2097072A GB8210522A GB8210522A GB2097072A GB 2097072 A GB2097072 A GB 2097072A GB 8210522 A GB8210522 A GB 8210522A GB 8210522 A GB8210522 A GB 8210522A GB 2097072 A GB2097072 A GB 2097072A
Authority
GB
United Kingdom
Prior art keywords
ring
inner ring
shaft
sealing
screws
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
GB8210522A
Other versions
GB2097072B (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Crane Packing Ltd
Original Assignee
Crane Packing Ltd
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Crane Packing Ltd filed Critical Crane Packing Ltd
Priority to GB8210522A priority Critical patent/GB2097072B/en
Publication of GB2097072A publication Critical patent/GB2097072A/en
Application granted granted Critical
Publication of GB2097072B publication Critical patent/GB2097072B/en
Expired legal-status Critical Current

Links

Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/36—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member connected by a diaphragm or bellow to the other member
    • F16J15/363—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member connected by a diaphragm or bellow to the other member the diaphragm or bellow being made of metal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16D—COUPLINGS FOR TRANSMITTING ROTATION; CLUTCHES; BRAKES
    • F16D1/00—Couplings for rigidly connecting two coaxial shafts or other movable machine elements
    • F16D1/06—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end
    • F16D1/08—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key
    • F16D1/09—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial clamping due to axial loading of at least one pair of conical surfaces
    • F16D1/093—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial clamping due to axial loading of at least one pair of conical surfaces using one or more elastic segmented conical rings forming at least one of the conical surfaces, the rings being expanded or contracted to effect clamping
    • F16D1/095—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial clamping due to axial loading of at least one pair of conical surfaces using one or more elastic segmented conical rings forming at least one of the conical surfaces, the rings being expanded or contracted to effect clamping with clamping effected by ring contraction only
    • F16D1/096—Couplings for rigidly connecting two coaxial shafts or other movable machine elements for attachment of a member on a shaft or on a shaft-end with clamping hub; with hub and longitudinal key with radial clamping due to axial loading of at least one pair of conical surfaces using one or more elastic segmented conical rings forming at least one of the conical surfaces, the rings being expanded or contracted to effect clamping with clamping effected by ring contraction only the ring or rings being located between the shaft and the hub
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/3404—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member and characterised by parts or details relating to lubrication, cooling or venting of the seal
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16J—PISTONS; CYLINDERS; SEALINGS
    • F16J15/00—Sealings
    • F16J15/16—Sealings between relatively-moving surfaces
    • F16J15/34—Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/3464—Mounting of the seal

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mechanical Sealing (AREA)

Abstract

A shaft seal including a sealing element 5 and a drive ring assembly 8 for mounting the sealing element with respect to a shaft, for rotation therewith; the drive ring assembly comprising a pair of concentric rings 9, 15 one mounted within the bore of the other, a plurality of circumferentially spaced radial clamping screws 13 in screw threaded engagement with the outer ring, so that they may be tightened against the outer surface 18 of the inner ring 15, the abutting surfaces of the screws and the inner ring being mutually inclined, so that tightening of the screws against the inner ring 15 will cause the inner ring to move axially towards a shoulder 11 in the bore of the outer ring 9, so as to compress a sealing ring 19 positioned between the shoulder 11 and the opposed end of the inner ring 9, thereby causing the sealing ring 19 to expand radially into sealing engagement with the opposed surfaces of the shaft 1 and the outer ring 9, while at the same time said screws 13 deform the inner ring into clamping engagement with the shaft 1. <IMAGE>

Description

SPECIFICATION Shaft seal This invention relates to shaft seals and in particular to a method of securing the sealing element associated with the shaft, to the shaft; in a manner such as to provide drive to the sealing element.
Hitherto the sealing elements of shaft seals which are associated with the shaft, have been attached to the shaft by means of a ring or collar which in turn is secured to the shaft by means of a plurality of circumferentially spaced radial clamping screw, these screws being tightened against the shaft to clamp the ring or collar thereto. With this method of securing the sealing element to the shaft, the clamping screws indent the surface of the shaft, making removal of the sealing element difficult and also necessitating the removal of any burrs so caused, so as not to damage the sealing elements when refitting the seal. Independent sealing means is also required between the shaft and the ring or collar.
According to one aspect of the present invention a shaft seal includes a sealing element and a drive ring assembly for mounting the sealing element with respect to a shaft, for rotation therewith; said drive ring assembly which is adapted to be mounted around a shaft comprising; an outer ring, the bore of which is enlarged towards one end, so that a radially or substantially radially extending shoulder is provided part way along its length; a radially deformable inner ring co-axial with the outer ring and located in the enlarged bore portion thereof; and a sealing ring located in the enlarged bore portion of the outer ring between the shoulder thereof and the opposed end of the inner ring; a plurality of circumferentially spaced radial screws engaging in corresponding threaded holes in the portion of the outer ring surrounding the inner ring, so that they may be tightened against the outer surface of the inner ring, the engaging surfaces of the screws and the inner ring being mutually inclined, so that tightening of the screws against the inner ring, when the assembly is positioned about a shaft, will force the inner ring to move axially towards the shoulder of the outer ring, thereby compressing the sealing ring positioned therebetween and causing the sealing ring to expand radially into sealing engagement with the opposed surfaces of the shaft and the outer ring, while at the same time said screws deform the inner ring into clamping engagement the shaft.
Preferably each of the radial screws engage an inclined portion of the outer surface of the inner ring, this inclined portion being positioned axially between the axes of the screw and the shoulder of the outer ring, so that tightening of the screw will cause axial movement of the inner ring towards the shoulder, while at the same time applying a radial clamping load to the inner ring. The outer surface may be provided with a series of inclined surface portions which are positioned circumferentially to coincide with the circumferential positions of the radial screws.
Such inclined surface portions may be in the form of conical depressions, which may for example be pressed in the inner ring or be in the form of counter-sunk holes. Alternatively, the inclined surface may be provided by a circumferential "V" section groove.
In order to permit radial deformation of the inner ring, a split ring may be used. alternatively, a closed ring of relatively light cross-section which is sufficiently flexible to permit the necessary deformation of the ring onto the shaft under the load applied by the radial screw, may be used.
Where a split ring is used in order to ensure a fluid tight seal, a closed back-up ring may be provided between the sealing ring and the split inner ring.
In order to provide secure location of the outer ring with respect to the shaft, the inner ring should be a tight fit within the bore of the outer ring, when the drive ring assembly is clamped upon the shaft. Where this is not the case, and the only contact between the inner and outer rings is via the radial screws, it is possible that the outer ring may be rocked relative to the inner ring. In order to avoid this problem, and also the need to produce the inner and outer rings to very close tolerances, the bore of the outer ring and the outer surfaces of the inner ring may be conical tapering towards the shoulder of the outer ring.In this manner as the inner ring moves axially towards the shoulder of the outer ring in order to compress the sealing ring, the opposed surfaces of the inner and outer ring is assembled on a shaft, the inner and outer rings will be brought into continuous circumferential engagement and the outer ring will thus be rigidly mounted with respect to the inner ring and the shaft.
The invention is now described, by way of example only, with reference to the accompanying drawings, in which: Figure 1 shows diagrammatically, in cross section along line I-I in Figure 2, a bellows seal formed in accordance with the present invention; Figure 2 shows a partial end view of the seal, shown in Figure 1; and Figure 3 shows diagrammatically in cross section an alternative form of drive ring assembly for a seal formed in accordance with the present invention.
As illustrated in the accompanying drawings, a mechanical face seal between a rotary shaft and housing 2 comprises an annular seat member 3 which is sealed into a recess in the housing 2 by an expanded graphite ring 4.
The sealing member 5 associated with the shaft 1, is held in contact with the seat 3 by means of a retaining ring 6 and metal bellows unit 7, the metal bellows unit 7 being welded to and acting against a drive ring assembly 8, in conventional manner.
The drive ring assembly 8 comprises an outer ring 9 having a bore which is slightly greater in diameter than the diameter of the shaft 1 at the end to which the bellows unit 7 is secured. The bore opens to form a recessed intermediate portion 10 with a radially extending shoulder 11 and has a conical rearward portion 12. A plurality of circumferentially spaced radial clamping screws 1 3 are provided in corresponding screw threaded holes 14 in the portion of the ring 9 having the conical bore 12. A longitudinally split ring 15, having a parallel bore slightly greater in diameter than the diameter of the shaft 1 and having a conical outer surface 16, which corresponds with the conical portion 1 2 of the bore of the outer ring 9, is located within the conical portion 12 of the bore of the ring 9.A plurality of counter-sunk holes 1 7 are provided in the split ring 15, these holes 1 7 corresponding circumferentially in position to the clamping screws 13, but being axially misaligned so that each of the screws 1 3 will engage the innermost sloping side 1 8 of one of the counter-sunk holes 17.
An expanded graphite packing ring 1 9 is located in the recessed portion 11 of the bore of ring 9 and a back-up ring 20 is located between this packing ring 1 9 and the inner end of the split ring 15.
In order to assemble the bellows seal described above, the seat 3 is secured to the housing 2 and sealed thereto by means of the expanded graphite ring 4, in known manner. The sealing member 5, with the retaining ring 6, bellows unit 7 and drive ring assembly 8, are then positioned on the shaft 1 and when in position, the drive ring assembly 8 is clamped and sealed to the shaft 1 by means of clamping screws 14. As each of the screws 14 are tightened against the sloping side 1 9 of the counter-sunk hole 1 7 associated therewith, the split ring 1 5 is moved axially with respect to the outer ring 9, towards the shoulder 11.As the split ring 1 5 moves axially with respect to the outer ring 9 the conical surfaces 12 and 1 6 are brought into continuous circumferential engagement, thereby clamping the outer ring 9 with respect to the split ring 1 5. At the same time, the split ring 1 5 is forced by the screws 13 into engagement with the shaft 1 , thereby clamping the whole assembly in position on the shaft 1. The axial movement of the split ring 1 5 also compresses the packing ring 1 9 axially between the shoulder 11 and the back-up ring 20, thus causing the packing ring 1 9 to expand radially against the surface of of the shaft 1 and the bore 10 of the ring 9, to provide a fluid tight seal.
In the shaft seal arrangement described above, the drive ring assembly 8 is clamped to the shaft 1 over the whole of the surface area of the bore of the split ring 1 5. As a result, there will be no distortion of the shaft 1 which will present difficulties when replacing the sealing member 5, as would occur with seals used hitherto in which the clamping is provided by the point contact of the ends of radial clamping screws, with the shaft.
By using expanded graphite packing rings 4 and 19, for sealing both the seat 3 and the drive ring assembly 8, the seal described above can be used safely over a wide range of temperatures.
In the embodiment illustrated in Figure 3, the outer ring 9 is provided with a plain cylindrical counter-bore 25. A closed inner ring 26 of L shaped section, having an inwardly directed flange 28, is machined to a close fit within the counterbore 25 of the outer ring 9. The inner ring 26 is provided with a series of pressed conical depressions 29 in its cylindrical surface, these conical depressions 29 being positioned such that they co-act with a series of radial screws 13, which are provided in screw threaded holes 14, in a counter-bore portion of the outer ring 9, in a manner similar to the counter-sunk holes 19 described with reference to the embodiment shown in Figure 1.
As illustrated in Figure 3, the drive ring assembly is mounted upon a shaft 1 with the inner ring 26 within the counter-bore 25 of the outer ring 9 and an expanded graphite sealing ring 1 9 is positioned between the shoulder 11 of the outer ring 9 and the flange portion 28 of the inner ring 26. As the flange portion 28 is continuous, there is no need in this embodiment for the back-up ring 20 used in the embodiment shown in Figure 1.
As the radial screws 13 are tightened against the inclined surface of the conical depressions 29, the inner ring will be moved axially towards.the shoulder 11 of the outer ring, thereby compressing the sealing ring 1 9.to provide a seal between the opposed surfaces of the shaft and the outer ring 9. At the same time, the inner ring 26 is deformed radially, so that the conical depressions 29 will be brought into clamping engagements with the shaft 1.
While in this embodiment, the inner ring 26 is only clamped to the shaft 1 over a relatively small areas, in comparison with the embodiment illustrated in Figure 1, distortion of the shaft will still be much smaller than that resulting from the use of radial screws clamping directly onto the shaft, as was done in the past.
Various modifications may be made without departing from the present invention. For example, while in the embodiments described above, inclined surfaces are provided on the outer surface of the inner ring, alternatively the radial screws may be provided with conical end portions which engage vertical portions of the inner ring. Also while the drive ring assembly described has been used in conjunction with metal bellows units, the assembly may be used for other types of mechanical face seals which use seal envelopes other than bellows units. The drive ring assembly may also be used for retaining the seat 3, where this is mounted for rotation with the shaft 1 rather than in fixed relationship to the housing, or in order to seal, for example, a sleeve to a shaft.

Claims (11)

1. A shaft seal including a sealing element and a drive ring assembly for mounting the sealing element with respect to a shaft, for rotation therewith; said drive ring assembly which is adapted to be mounted around a shaft comprising: an outer ring the bore of which is enlarged towards one end, so that a radially or substantially radially extending shoulder is provided part way along its length; a radially deformable inner ring co-axial with the outer ring and located in the enlarged bore portion thereof; and a sealing ring located in the enlarged bore portion of the outer ring between the shoulder thereof and the opposed end of the inner ring; a plurality of circumferentially spaced radial screws engaged in correspondingly threaded holes in the portion of the outer ring surrounding the inner ring, so that they may be tightened against the outer surface of the inner ring, the engaging surfaces of the screws and the inner ring being mutually inclined, so that tightening of the screws against the inner ring, when the assembly is positioned about a shaft, will force the inner ring to move axially towards the shoulder of the outer ring, thereby compressing the sealing ring positioned therebetween and causing the sealing ring to expand radially into sealing engagement with the opposed surfaces of the shaft and the outer ring, while at the same time said screws deform the inner ring into clamping engagement with the shaft,
2.A shaft seal according to Claim 1 in which each screw engages an inclined portion of the outer surface of the inner ring, said inclined portion being disposed on the side of the axes of the screw nearest to the shoulder of the outer ring,
3. A shaft according to Claim 2 in which each inclined portion of the surface of the inner ring, is provided by a conical depression in the inner ring, a series of conical depressions being provided in the inner ring corresponding circumferentially to the positions of the screws.
4. A shaft seal according to Claim 2 in which the inclined portion of the surface of the inner ring is provided by a circumferential "V" section groove.
5. A shaft seal according to any one of the preceding claims in which the inner ring is split in order to permit radial deformation.
6. A shaft seal according to Claim 5 in which an annular back-up ring is provided between the sealing ring and the split inner ring.
7. A shaft seal according to any one of the preceding claims in which the bore of the outer ring and the outer surface of the inner ring are conical, reducing in diameter towards the shoulder of the outer ring, so that as the inner ring is moved axially towards the shoulder of the outer ring, the opposed surfaces of the inner and outer rings will be brought together into continuous circumferential engagement, thereby clamping the outer ring with respect to the inner ring and thus with respect to the shaft.
8. A shaft seal according to any one of claims 1 to 4, in which the inner ring is formed from a closed ring of light cross-section.
9. A shaft seal according to any one of the preceding claims in which the sealing ring is made from expanded graphite material.
10. A shaft seal according to any one of the preceding claims in which a metal bellows unit is secured at one end to the outer ring of the drive ring assembly and at the other end to a sealing element.
11. A shaft seal substantially described herein, with reference to and as shown in, Figures 1 and 2 of the accompanying drawings.
1 2. A shaft seal substantially as described herein with reference to, and as shown in Figure 3 of the accompanying drawings.
GB8210522A 1981-04-21 1982-04-08 Mounting a sealing element Expired GB2097072B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB8210522A GB2097072B (en) 1981-04-21 1982-04-08 Mounting a sealing element

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
GB8112403 1981-04-21
GB8210522A GB2097072B (en) 1981-04-21 1982-04-08 Mounting a sealing element

Publications (2)

Publication Number Publication Date
GB2097072A true GB2097072A (en) 1982-10-27
GB2097072B GB2097072B (en) 1985-01-23

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Family Applications (1)

Application Number Title Priority Date Filing Date
GB8210522A Expired GB2097072B (en) 1981-04-21 1982-04-08 Mounting a sealing element

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Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2258019A (en) * 1991-07-24 1993-01-27 Crane John Uk Ltd Mechanical face seals
GB2260378A (en) * 1991-10-10 1993-04-14 Aes Eng Ltd Mechanical seals
US5544897A (en) * 1993-08-19 1996-08-13 A. W. Chesterton Co. Cartridge seal having a high contact pressure seal and means for intersleeve adjustment including quench fluid delivery
CN1081766C (en) * 1997-05-27 2002-03-27 Smc株式会社 Valve seal mechanism
WO2017099647A1 (en) 2015-12-11 2017-06-15 Roplan Holding Ab A holding device for application of a sealing element on a shaft

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2258019A (en) * 1991-07-24 1993-01-27 Crane John Uk Ltd Mechanical face seals
US5332235A (en) * 1991-07-24 1994-07-26 John Crane Uk Limited Mechanical face seals
GB2260378A (en) * 1991-10-10 1993-04-14 Aes Eng Ltd Mechanical seals
US5344164A (en) * 1991-10-10 1994-09-06 Aes Engineering Limited Mechanical seals
GB2260378B (en) * 1991-10-10 1995-07-05 Aes Eng Ltd Mechanical seals
US5544897A (en) * 1993-08-19 1996-08-13 A. W. Chesterton Co. Cartridge seal having a high contact pressure seal and means for intersleeve adjustment including quench fluid delivery
CN1081766C (en) * 1997-05-27 2002-03-27 Smc株式会社 Valve seal mechanism
WO2017099647A1 (en) 2015-12-11 2017-06-15 Roplan Holding Ab A holding device for application of a sealing element on a shaft
CN108368886A (en) * 2015-12-11 2018-08-03 洛普兰控股公司 Holding meanss for being applied in sealing element on axis
EP3387279A4 (en) * 2015-12-11 2019-08-14 Roplan Holding AB A holding device for application of a sealing element on a shaft
CN108368886B (en) * 2015-12-11 2020-09-08 洛普兰控股公司 Retaining device for applying a sealing element to a shaft

Also Published As

Publication number Publication date
GB2097072B (en) 1985-01-23

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PCNP Patent ceased through non-payment of renewal fee