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
  • F16J15/3404—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
  • F16J15/3408—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 at least one ring having an uneven slipping surface
  • F16J15/3412—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 at least one ring having an uneven slipping surface with cavities
  • F16J15/342—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 at least one ring having an uneven slipping surface with cavities with means for feeding fluid directly to the face
• • 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
  • F16J15/3436—Pressing means
  • F16J15/3448—Pressing means the pressing force resulting from fluid pressure
• • 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
  • F16J15/3472—Means for centering or aligning the contacting faces

Definitions

• This invention relates to a rotary mechanical face seal of the type used to provide a seal between two members when one is moving in rotation relative to the other, for example a seal between the stationary wall of a housing of a pump or engine and a shaft extending through the wall.
• Such mechanical seals are used to prevent leakage of fluid between the shaft and the housing while permitting rotation of the shaft.
• the invention is herein described with emphasis on a mechanical seal for use to prevent leakage of a fluid under a pressure higher than atmospheric pressure from a housing containing the fluid to atmospheric pressure outside the housing.
• upstream is herein used to mean a pressure on the high pressure side of a leakage path or potential leakage path of the fluid.
• fluid pressure herein refer to the difference between the pressure inside and outside the housing and assume atmospheric pressure outside the housing and a higher than atmospheric pressure in the fluid. It will however be understood that in other embodiments of the invention apparatus generally similar to that to be described may be used when pressure outside the housing is higher than that inside the housing.
• a tubular passage through which a shaft extends coaxially, a stationary seal seat mounted to and providing a seal with the passage, a drive ring mounted for rotation with the shaft and a ring element surrounding the shaft between the seat and the drive ring.
• the ring element is typically extended in the axial direction and has a ring face which is urged against the stationary seat face by springs acting between the drive ring and the ring element with a force sufficient to prevent leakage across a primary seal interface between the rotating ring face of the ring element and of the seat face of the stationary seal seat.
• the drive ring extends into the annular recess and provides a surface which permits limited sliding movement of the ring element with respect thereto in the axial direction while substantially maintaining the alignment of the ring element.
• An 0-ring seal grooved in the drive ring forms a secondary seal between the ring element and the drive ring and an O-ring between the drive ring and the shaft prevents leakage along the shaft surface.
• the present invention stems from the suprising discovery that a very light hydraulic loading urging the ring element against the stationary seal seat will suffice to maintain a seal at fluid pressures upstream of the primary interface of up to in excess of 2000 psi and without seizure if the seal member is damped against movement away from the seal face.
• Preferred embodiments of the invention provide a seal which is substantially self-aligning, which withstands high pressures, which is effective over a wide range of pressures and which is relatively inexpensive to manufacture and install in comparison especially with previously available high pressure rotary seals.
• the invention consists in a mechanical seal apparatus for providing a seal between two members when one member is rotating relative to the other said apparatus comprising: a seal seat fixedly mounted to and sealed with one of said members, said seal seat having a seat face, a ring element having a ring face adapted in the operating position of the ring element to bear against said seat face to provide a primary seal at the interface therebetween, said ring element being mounted to the other of said members by means permitting tanslational movement of said ring face towards or away from said seat face while maintaining a seal between the ring element and said other member; and wherein said ring element in order to move away from its operating position must displace a non-compressible fluid from a sealed chamber having a restricted aperture means permitting inlet and outlet of said fluid from said chamber.
• the invention consists in apparatus according to the first aspect wherein said chamber is in communication with a location at the ring element ring face which is between the upstream (as herein defined) and the downstream (as herein defined) edge of the primary interface.
• Figures 1 to 2 and 4 to 6 are schematic diagrams showing a portion of various embodiments, each different from the other, of a seal assembly in diametric section.
• Figure 3 shows a part of the embodiment of Figure 2, viewed in the axial direction.
• Figure 7 shows a preferred embodiment of the invention in section.
• Figure 8 shows a part end view of a ring element being a part of the embodiment shown in Figure 7. Best mode of carrying out the Invention
• the embodiment is a mechanical seal permitting rotation of shaft 1 with within a housing 2 in which oil at a pressure P greater than atmospheric pressure A is maintained.
• Shaft 1 extends to outside housing 2 which is at atmospheric pressure A.
• the seal comprises an annular seal seat member 21 having a seat face 22 and sealed by means (not shown) with housing 2.
• the seal further comprises a ring element 3 and a drive ring 4.
• Drive ring 4 is mounted to shaft 1 and comprises a generally cylindrical member sleeved oh shaft 1 and having an annular space defined between an inner cylindrical collar 40 adjacent to shaft 1 and an outer cylindrical collar 42 spaced radially apart therefrom.
• the annular space is thus between a first cylindrical surface 41 on the radially outer side of inner collar 40 and a second cylindrical surface 43 on the inner side of outer cylindrical collar 42.
• the annular space of drive ring 4 so defined is closed at one end by a wall 44 of drive ring 4 and is open at an end 45 which faces seat face 22.
• Ring element 3 is interposed between seat face 22 and drive ring 4 and surrounds shaft 1.
• Ring element 3 has a ring face 31 which in the working position of ring element 3 is in abutment with seat face 22 at a common interface which is the primary seal interface.
• the opposite end of seal ring element 3 is annular, having an outer annular surface 32 and an inner annular surface 33 and is housed within the annular space defined between walls 41 and 43 of drive ring 4.
• Drive ring 4 is mounted to shaft 1 by suitable means, for example, by threaded engagement therewith.
• First seal means being an "O" ring 51, grooved in drive ring 4 at its innermost circumference, provide a seal between drive ring 4 and shaft 1 preventing leakage of fluid under a pressure P greater than atmospheric pressure A upstream from seal along the shaft outer circumference towards the outer circumference towards the atmospheric pressure.
• a second seal means being an "O" ring 52 is grooved in first cylindrical surface 41 of inner cylindrical collar 40 of drive ring 4 and extends between collar 41 and the outer annular surface 33 of ring element 3.
• a third seal means being an "O" ring 53 grooved in drive ring 4 extends between second cylindrical collar 42 of drive ring 4 from the second cylindrical surface 43 to outer surface 32 of ring element 3.
• a narrow passageway 8, or preferably a plurality of passageways provides an inlet and outlet communicating between the interior of the sealed chamber and are under pressure P surrounding the drive ring 4 when the apparatus is in use.
• Pin means 11 having one end received in a blind hole in drive ring 4 and having the other pin and received in a blind hole of ring element 3 are adapted to drive ring element 3 in rotation with shaft 1 while permitting axial movement of ring element 3.
• "O" rings 52 and 53 also permit limited movement in the axial direction of ring element 3.
• the sealed chamber becomes filled with oil under pressure and urges the ring element into engagement with the stationary seal seat at a primary seal interface of surface 22 and surface 31.
• any tendancy of the ring element to move away from the seat face requires displacement of fluid from the sealed chamber through narrow passageway 8 and is resisted by the fluid in the sealed chamber.
• Forces acting to maintain the ring element 3 in abutment with the seat increase as the pressure in the fluid increases, that is to say as the pressure against which the seal is effective increases.
• the area of surface 34 may be small in comparison with that of the primary seal interface.
• springs 13 may be interposed between drive ring 4 and ring element 3.
• Figure 2 is similar to that shown in Figure 1 but differs in that passageways 8 extend in an axial direction through ring element 3 and communicate with a location on ring face 31 of ring element 3 between the outer radial and inner radial circumference thereof of ring face 3.
• a groove 35 more clearly visable in Figure 3 is recessed in the ring face 31 at a radius intermediate the inner and outer radial edge thereof.
• One or more passageways 8 (of which four are shown in Figure 3) communicate between groove 35 and the chamber defined between walls 34 and 44 ( Figure 2) .
• Ring element 3 is stepped diameter on its internal surface having a greater diameter at the ring face 33 than at the opposite end 34.
• the step indicated at 36 occurs between seals 52 and 54.
• Drive ring 3 is stepped on surface 41 in the opposite sence as indicated at 46.
• a sealed chamber is defined between surfaces 33 and surface 41 between seals 54 and 52 and including stepped surfaces 36 and 46.
• Communication between the chamber so defined and fluid at pressure P surrounding ring element 3 is by at least one passage means 8 extending in a radial direction through ring element 3.
• - li ⁇ lt should be noted that in this embodiment the chamber defined between surfaces 34 and 44 is not a sealed chamber containing a fluid and may communicate with atmosphere for example via a passageway (not shown) on shaft 1.
• the force acting on the ring element 3 with a component tendency to urge it towards seat face 21 in the embodiment of Figure 4 acts on a very small annular area of drive ring 3 at step 36.
• drive ring 4 defines an annular space between inner cylindrical surface 43 of outer collar 42 and shaft 1.
• a thrust element 9 which is also of generally annular shape is housed within the annular space between shaft 1 and cylindrical surface 43.
• End wall 44 has ⁇ equiangularly spaced blind holes 14 drilled therein to receive springs 91 which bear against flange 93 of the thrust element and urge it into abutment with ring element 3 at wall 34, in turn urging ring face 31 against seat face 21.
• Thrust element 9 does not seal with shaft 1.
• the outer annular surface 92 of thrust element 9 acts similarly to surface 41 of the embodiment of Figure 4. It is similarly stepped between "O" ring seals 54 and 52 with ring element 3.
• a sealed chamber is provided between seals 54 and 52 the stepped outer surface 92 of thrust element 9 and a stepped inner surface 33 of ring element 3 communication with fluid at pressure P is via grooves 8 for preference communicating with ring face 31.
• FIGS. 7 and 8 show in more detail a preferred embodiment and the same numerals are used to describe the embodiment as are used to describe similar parts of earlier embodiments.
• the chamber defined between surfaces 33, 92 and "0" rings 52, 54 communicates with ring face 3 by two passageways 8.
• the passageways intercommunicate at the ring face by a coaxial groove 35 as also shown in the embodiment described with reference to Figure 3.
• Figures 7 and 8 also show drive pins 11 which extends from a recess in drive ring 4 through flange 93 of thrust element 9 and into a cavity of ring element 3.
• Three drive pins 11 are provided at equiangular spacing.
• Springs 13 maintain ring face 31 in contact with seat face 22 when fluid in the apparatus is substantially not under pressure.
• Figure 6 illustrates an embodiment in which a sealed chamber is provided between drive ring face 44, seal 53 and face 34 of ring element 3.
• inlet and outlet of fluid to the chamber is at an annular gap at the periphery of the chamber.
• a passage thru shaft 1 communicates with the space defined between seals 52, 51 and 53 and has no significant effect on the normal working of the seal.
• Figure 9 illustrates an embodiment in which the ring element has a collar which sleeves the drive ring and in which the sealed chamber is defined between shaft 1 drive ring wall 44, ring element wall 34 and seal 53.
• the seal interface preferably has a carbon seat member and a steel face ring.
• seal may be modified for situations in which a pressure within the housing is lower than that outside the housing and that the elements described herein as mounted to the rotating member may in other embodiments be exchanged with those mounted to the stationary member without departing from the invention herein described.
• the invention has industrial application in pumps, motors, compressors and generally when leakage of fuild between a shaft and stationary parts.

Landscapes

• Engineering & Computer Science (AREA)
• General Engineering & Computer Science (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Fluid Mechanics (AREA)
• Mechanical Sealing (AREA)

Applications Claiming Priority (2)

Publications (2)

Family

ID=3768408

Family Applications (1)

Country Status (6)

Families Citing this family (1)

Citations (8)

Family Cites Families (2)

• 1981
  • 1981-01-13 ZA ZA00810208A patent/ZA81208B/xx unknown
  • 1981-01-15 EP EP19810900206 patent/EP0044317A4/fr not_active Withdrawn
  • 1981-01-15 WO PCT/AU1981/000007 patent/WO1981002052A1/fr not_active Application Discontinuation
  • 1981-01-15 BR BR8105996A patent/BR8105996A/pt unknown
  • 1981-01-15 JP JP50038781A patent/JPS56501892A/ja active Pending
  • 1981-01-16 IT IT8183305A patent/IT8183305A0/it unknown

Patent Citations (8)

Also Published As

Similar Documents

Legal Events