CA1049583A - Sealing means - Google Patents
Sealing meansInfo
- Publication number
- CA1049583A CA1049583A CA242,956A CA242956A CA1049583A CA 1049583 A CA1049583 A CA 1049583A CA 242956 A CA242956 A CA 242956A CA 1049583 A CA1049583 A CA 1049583A
- Authority
- CA
- Canada
- Prior art keywords
- assembly
- carrier
- packing
- flexible carrier
- soft packing
- 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.)
- Expired
Links
Landscapes
- Sealing Devices (AREA)
Abstract
ABSTRACT
A sealing means for insertion between the shaft and housing of a pump in which the seal is constituted by a soft packing enclosed in a flexible carrier which has on its outer surface a fluid dispersion arrangement, the soft packing being radially loaded by hydraulic fluid. The packing and carrier may be enclosed in a metal sleeve and holes may be provided through the packing and/or carrier wall.
A sealing means for insertion between the shaft and housing of a pump in which the seal is constituted by a soft packing enclosed in a flexible carrier which has on its outer surface a fluid dispersion arrangement, the soft packing being radially loaded by hydraulic fluid. The packing and carrier may be enclosed in a metal sleeve and holes may be provided through the packing and/or carrier wall.
Description
~0495~3 The invention relates to a stuffing box assembly and especially to soft-packed seals suitable for use in sealing pumps, mixers, compressors, valves and the like.
The traditional practice in sealing machinery subject to fluid leakage is to arrange that shafts or the like project from the machinery through a cylindrical housing. The sealing arrangement is then disposed in the annular space between the housing and the shaft, being`essentially in sealing connection with both the shaft and the housing. More specifically when soft packing is used as the sealing means, the annular space is filled with soft packing and its associated spacing pieces and adaptors, said soft packing being in contact with both the bore of the housing and of the shaft. The packing i5 then loaded by means of an adjustable gland plate positively posi- -tioned relative to the face of the housing. An axial loading is produced in the packing in the direction of the axis of the shaft and housing. The packing is then deformed by the axial load both axially and radially so that the existing contacts between the packing, housing bore and shaft become sealing `
~0 contacts resisting the tendency of fluid to leak from the machinery. The disadvantages of the conventional soft packed stuffing box outlined above are uneven loading in the axial length of the packing, difficulties in the replacement of the `
packing and where the shaft revolves, uneven shaft wear and frequent ad~ustment of the gland plate.
It has been proposed to provide a soft packed seal of a radially-loaded nature, the radial loading being effected by a fluid medium.
~, .:
~49S83 : However, the construction of seal employed in such proposal is difficult to instal and the loading fluid distri-bution is non-uniform, and it is an ohject of the present invention to obviate or mitigate these drawbacks.
According to the present invention there is provided a stuffing box assembly comprising a shaft rotatably mounted within a housing, a soft packing formed as a cylindrical sleeve, surrounding the shaft, an encapsulating flexible elastomeric cylindrical imperforate carrier surrounding the soft packing and having at each end an inturned end flange abutting the adjacent end of the soft packing, a rigid sleeve surrounding the flexible carrier in contiguous relationship therewith, spaced formations on the cylindrical surface of the flexible carrier to define therebetween and the rigid sleeve a passage-way for dispersion over the surface of the flexible carrier of a loading fluid, and axially spaced radially extending holes ;
in said soft packing for penetration of a fluid to be sealed into the soft packing.
: ' ~3 .
1049S~3 The soft pac~ing and flexible carrier may be diamet-rically split in an axial direction.
The sealing means according to the present invention permits a uniform radial loading of the packing; a reduction in the frequency of adjustment of the packing; standardisation of the paclcing arrangement for a given size of shaft or other determining factor; easier adjustment; and simpler replacement ~ -of a worn packing.
An embodiment of the present invention will now be described by way of example, with reference to the accompanying drawing, in which: -Fig. 1 is a diagrammatic section of a stuffing box assembly suitable for use with a pump; -Fig. 2 is a fragmentary view of a modification of the stuffing box assembly shown in Fig. 1. ``
In Figure 1, the stuffing box assembly comprises a ~;
pump shaft 1 surrounded by a housing 2. It is desired to pre-vent leakage of fluid through the annular . . :
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~049S83 space 3 between the housing 2 and the shaft 1 which is rotatable.
A packing 4 of, for example, an asbestos composite is arranged around the shaft 1 and is encapsulated in a carrier 5 of a flex- -ible nature. The packing 4 may be preformed to a cylindrical shape and may consist of a single component or be split along the axis of the shaft to provide two or more components. Simi-larly, the carrier 5 is axially split to match the packing 4 and is constructed of an elastomeric flexible material, such for example, as synthetic rubber. The carrier 5 is also provided with circumferential and/or axial pro~ections 6, grooves or -other arrangements on its outer circumferential surface to faci-litate distribution or dispersion of a loading fluid. The carrier 5 is located in a metal sleeve 7 against an inwardly turned lip 8.thereof at the fluid or inner end, the sleeve 7 being in contiguous contact with the carrier 5 along its inner diameter. The radial thickness of the sleeve 7 is so arranged that it is easily accommodated within the annular space 3. The sleeve 7 may alternatively or additionally be provided loading ;;
fluid dispersion arrangements.
The sleeve 7 is of greater length than the carrier 5 and has a radially outwardly directed flange 9 at its outer end.
The flange 9 is sealed against the face of the housing 2 by a ;
gasket 10, and is held in position by a gland plate 11, an '0'-ring 12 being interposed between the gland plate 11 and flange 9. The sleeve 7 may, if desired, be located on the gland plate 11 by a spigot arrangement for ease of location and fitting.
Alternatively, the spigot arrangement may be omitted and the carrier 5 may be the same length as the plate 7, the packing 4 being appropriately dimensioned.
1(~49583 The gland plate 11 is held positively in relation to the housing
The traditional practice in sealing machinery subject to fluid leakage is to arrange that shafts or the like project from the machinery through a cylindrical housing. The sealing arrangement is then disposed in the annular space between the housing and the shaft, being`essentially in sealing connection with both the shaft and the housing. More specifically when soft packing is used as the sealing means, the annular space is filled with soft packing and its associated spacing pieces and adaptors, said soft packing being in contact with both the bore of the housing and of the shaft. The packing i5 then loaded by means of an adjustable gland plate positively posi- -tioned relative to the face of the housing. An axial loading is produced in the packing in the direction of the axis of the shaft and housing. The packing is then deformed by the axial load both axially and radially so that the existing contacts between the packing, housing bore and shaft become sealing `
~0 contacts resisting the tendency of fluid to leak from the machinery. The disadvantages of the conventional soft packed stuffing box outlined above are uneven loading in the axial length of the packing, difficulties in the replacement of the `
packing and where the shaft revolves, uneven shaft wear and frequent ad~ustment of the gland plate.
It has been proposed to provide a soft packed seal of a radially-loaded nature, the radial loading being effected by a fluid medium.
~, .:
~49S83 : However, the construction of seal employed in such proposal is difficult to instal and the loading fluid distri-bution is non-uniform, and it is an ohject of the present invention to obviate or mitigate these drawbacks.
According to the present invention there is provided a stuffing box assembly comprising a shaft rotatably mounted within a housing, a soft packing formed as a cylindrical sleeve, surrounding the shaft, an encapsulating flexible elastomeric cylindrical imperforate carrier surrounding the soft packing and having at each end an inturned end flange abutting the adjacent end of the soft packing, a rigid sleeve surrounding the flexible carrier in contiguous relationship therewith, spaced formations on the cylindrical surface of the flexible carrier to define therebetween and the rigid sleeve a passage-way for dispersion over the surface of the flexible carrier of a loading fluid, and axially spaced radially extending holes ;
in said soft packing for penetration of a fluid to be sealed into the soft packing.
: ' ~3 .
1049S~3 The soft pac~ing and flexible carrier may be diamet-rically split in an axial direction.
The sealing means according to the present invention permits a uniform radial loading of the packing; a reduction in the frequency of adjustment of the packing; standardisation of the paclcing arrangement for a given size of shaft or other determining factor; easier adjustment; and simpler replacement ~ -of a worn packing.
An embodiment of the present invention will now be described by way of example, with reference to the accompanying drawing, in which: -Fig. 1 is a diagrammatic section of a stuffing box assembly suitable for use with a pump; -Fig. 2 is a fragmentary view of a modification of the stuffing box assembly shown in Fig. 1. ``
In Figure 1, the stuffing box assembly comprises a ~;
pump shaft 1 surrounded by a housing 2. It is desired to pre-vent leakage of fluid through the annular . . :
' ~'' ''~' ,.
"' ', ' ~
.... : ., .
- 4 - ~
~049S83 space 3 between the housing 2 and the shaft 1 which is rotatable.
A packing 4 of, for example, an asbestos composite is arranged around the shaft 1 and is encapsulated in a carrier 5 of a flex- -ible nature. The packing 4 may be preformed to a cylindrical shape and may consist of a single component or be split along the axis of the shaft to provide two or more components. Simi-larly, the carrier 5 is axially split to match the packing 4 and is constructed of an elastomeric flexible material, such for example, as synthetic rubber. The carrier 5 is also provided with circumferential and/or axial pro~ections 6, grooves or -other arrangements on its outer circumferential surface to faci-litate distribution or dispersion of a loading fluid. The carrier 5 is located in a metal sleeve 7 against an inwardly turned lip 8.thereof at the fluid or inner end, the sleeve 7 being in contiguous contact with the carrier 5 along its inner diameter. The radial thickness of the sleeve 7 is so arranged that it is easily accommodated within the annular space 3. The sleeve 7 may alternatively or additionally be provided loading ;;
fluid dispersion arrangements.
The sleeve 7 is of greater length than the carrier 5 and has a radially outwardly directed flange 9 at its outer end.
The flange 9 is sealed against the face of the housing 2 by a ;
gasket 10, and is held in position by a gland plate 11, an '0'-ring 12 being interposed between the gland plate 11 and flange 9. The sleeve 7 may, if desired, be located on the gland plate 11 by a spigot arrangement for ease of location and fitting.
Alternatively, the spigot arrangement may be omitted and the carrier 5 may be the same length as the plate 7, the packing 4 being appropriately dimensioned.
1(~49583 The gland plate 11 is held positively in relation to the housing
2 by retaining bolts 13 or similar, and is arranged to project into the sleeve 7 so that it is in abutment with the carrier 5 as indicated at 14. A passageway 15 is arranged in the gland -plate 11 to facilitate the transfer of a loading fluid from a convenient point on the gland plate to the annular space 16 between the sleeve 7 and the carrier 5. Several such passageways may be arranged between this annular space and convenient points -~
on the gland plate. One of the passageways 15 is provided with a pressure relief valve 17 to prevent overload of the assembly.
It is preferred that the relief pressure of the valve 17 be set to a value that is close to and slightly in excess of the loading fluid pressure.
~ In Figure 2, a series of axially and circumferentially spaced holes 4A are provided which extend radially through the packing 4 to prevent undue pressure build up and permit a free transfer-of fluid from the shaft area into the packing. Similarly, a series of axially and circumferentially spaced holes 5A are provided which extend radially through the carrier 5. These holes 4A and/or 5A prevent undue pressure build up between the carrier 5 and the packing 4, for example, due to heat, and, when the holes 4A and 5A are both provided, allow access of the loading fluid from the annular spaces 16 to the interface between the carrier 5 and the packing. However, in accordance with the invention, only the holes 4A are provided.
. , ''`
`~
' :. . . , . : : .
~04~S83 In operation, the loading fluid, for example grease or hydraulic fluid, is injected into the passageway 15 or one or more thereof under pressure. The fluid flows into the annular space 16 between the sleeve 7 and the carrier 5 being uniformly dispersed around the outer diameter of the carrier 5. In the -embodiment in accordance with the invention, i.e. when holes 5A ~
are not used, leakage of the loading fluid is sufficiently pre- -vented by the radial sealing effect of the sleeve 7 and the gland plate 11 with the end faces of the carrier 5. The pres-sure of the loading fluid is transmitted vla the carrier 5 to the packing 4 and the shaft 1. As the pressure is evenly dis- -tributed over the carrier 5 then the pressure between the shaft 1 and the packing 4 is substantially uniform over the contact area of the packing.
Replacement of the packing 4 is by way of loosening bolts 13, sliding the gland plate 11 away from the housing 2 and then extracting the sleeve 7 with the packing 4 and carrier 5 within it. Having relocated the packing 4 and carrier 5 exter-nal to the housing 2 the sleeve 7 may then be returned into the ~-housing 2, a~ the used packing 4 and carrier 5 having been removed from the shaft 1 and been replaced by a similar unused set. The sleeve 7 is then returned over the packing 4 and carrier S and the entire unit relocated by returning the gland plate 11 to its ori~inal position, finally retaining the assembly by the bolts 13. Throughout the replacement operation care must be taken to ensure that the seal 12 and gasket 10 are not dam~
aged and are satisfactorily repositioned.
.- - .
.: ' . , ' , .
-`.. ---` ~49~83 Tt will be appreciated that the above arrangemen~
of packing assembl~ is b~ way of example and other arrangernents , of simila~ nature, utilisin~ the basic packing and carrier arrangement can be desi~ned.
In a modirication, the sleeve 7 and its fl~nges 8 and 9 are oinitted, the interior of the pump housin~ 2 being suitably configured to take the place, and serve the function, of the plate 7.
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on the gland plate. One of the passageways 15 is provided with a pressure relief valve 17 to prevent overload of the assembly.
It is preferred that the relief pressure of the valve 17 be set to a value that is close to and slightly in excess of the loading fluid pressure.
~ In Figure 2, a series of axially and circumferentially spaced holes 4A are provided which extend radially through the packing 4 to prevent undue pressure build up and permit a free transfer-of fluid from the shaft area into the packing. Similarly, a series of axially and circumferentially spaced holes 5A are provided which extend radially through the carrier 5. These holes 4A and/or 5A prevent undue pressure build up between the carrier 5 and the packing 4, for example, due to heat, and, when the holes 4A and 5A are both provided, allow access of the loading fluid from the annular spaces 16 to the interface between the carrier 5 and the packing. However, in accordance with the invention, only the holes 4A are provided.
. , ''`
`~
' :. . . , . : : .
~04~S83 In operation, the loading fluid, for example grease or hydraulic fluid, is injected into the passageway 15 or one or more thereof under pressure. The fluid flows into the annular space 16 between the sleeve 7 and the carrier 5 being uniformly dispersed around the outer diameter of the carrier 5. In the -embodiment in accordance with the invention, i.e. when holes 5A ~
are not used, leakage of the loading fluid is sufficiently pre- -vented by the radial sealing effect of the sleeve 7 and the gland plate 11 with the end faces of the carrier 5. The pres-sure of the loading fluid is transmitted vla the carrier 5 to the packing 4 and the shaft 1. As the pressure is evenly dis- -tributed over the carrier 5 then the pressure between the shaft 1 and the packing 4 is substantially uniform over the contact area of the packing.
Replacement of the packing 4 is by way of loosening bolts 13, sliding the gland plate 11 away from the housing 2 and then extracting the sleeve 7 with the packing 4 and carrier 5 within it. Having relocated the packing 4 and carrier 5 exter-nal to the housing 2 the sleeve 7 may then be returned into the ~-housing 2, a~ the used packing 4 and carrier 5 having been removed from the shaft 1 and been replaced by a similar unused set. The sleeve 7 is then returned over the packing 4 and carrier S and the entire unit relocated by returning the gland plate 11 to its ori~inal position, finally retaining the assembly by the bolts 13. Throughout the replacement operation care must be taken to ensure that the seal 12 and gasket 10 are not dam~
aged and are satisfactorily repositioned.
.- - .
.: ' . , ' , .
-`.. ---` ~49~83 Tt will be appreciated that the above arrangemen~
of packing assembl~ is b~ way of example and other arrangernents , of simila~ nature, utilisin~ the basic packing and carrier arrangement can be desi~ned.
In a modirication, the sleeve 7 and its fl~nges 8 and 9 are oinitted, the interior of the pump housin~ 2 being suitably configured to take the place, and serve the function, of the plate 7.
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'' .
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, .' , -' ~ . .
i~ 8 ~ ... .
- ~r - - ,, " ~ ' ., ' ,~ ~ ,.,
Claims (9)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A stuffing box assembly comprising a shaft rotatably mounted within a housing, a soft packing formed as a cylindrical sleeve surround the shaft, an encapsulating flexible elastomeric cylindrical imperforate carrier surrounding the soft packing and having at each end an inturned end flange abutting the adjacent end of the soft packing, a rigid sleeve surrounding the flexible carrier in contiguous relationship therewith, spaced formations on the cylindrical surface of the flexible carrier to define therebetween and the rigid sleeve a passageway for dispersion over the surface of the flexible carrier of a loading fluid, and axially spaced radially extending holes in said soft packing for penetration of a fluid to be sealed into the soft packing.
2. An assembly as claimed in claim 1 in which the soft packing and the flexible carrier are axially split along the axis of the sleeve.
3. An assembly as claimed in claim 1 in which spaced formations on the cylindrical surface of the flexible carrier are a series of circumferential and/or axial grooves in the carrier's outer surface.
4. An assembly as claimed in claim 1 in which the rigid sleeve is of greater length than the flexible carrier and has a radially outwardly-directed flange detachably securable to a gland plate, which has passageways for introducing the loading fluid to the outer diameter of the flexible carrier, one of the passageways being connected to a pressure relief mechanism at its outer end.
5. An assembly as claimed in claim 4 in which the pressure relief mechanism is a pressure relief valve.
6. An assembly as claimed in claim 1 or 2 in which a fluid dispersion arrangement is provided on the inner surface of the rigid sleeve.
7. An assembly as claimed in claim 4 in which an O-ring is interposed between the gland plate and the flange.
8. An assembly as claimed in claim 7 wherein the flange is sealed against the face of the housing by a gasket.
9. An assembly as claimed in claim 8 in which the plate is fixed to the housing by retaining bolts.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA242,956A CA1049583A (en) | 1976-01-05 | 1976-01-05 | Sealing means |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA242,956A CA1049583A (en) | 1976-01-05 | 1976-01-05 | Sealing means |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1049583A true CA1049583A (en) | 1979-02-27 |
Family
ID=4104897
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA242,956A Expired CA1049583A (en) | 1976-01-05 | 1976-01-05 | Sealing means |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1049583A (en) |
-
1976
- 1976-01-05 CA CA242,956A patent/CA1049583A/en not_active Expired
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