CA1187128A - Grooved mechanical face seal - Google Patents

Grooved mechanical face seal

Info

Publication number
CA1187128A
CA1187128A CA000410428A CA410428A CA1187128A CA 1187128 A CA1187128 A CA 1187128A CA 000410428 A CA000410428 A CA 000410428A CA 410428 A CA410428 A CA 410428A CA 1187128 A CA1187128 A CA 1187128A
Authority
CA
Canada
Prior art keywords
face
seal ring
rotating
shaft
seal
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
Application number
CA000410428A
Other languages
French (fr)
Inventor
Richard F. Salant
Clinton A. Boyd
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.)
Hughes Tool Co
Original Assignee
Hughes Tool Co
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 Hughes Tool Co filed Critical Hughes Tool Co
Application granted granted Critical
Publication of CA1187128A publication Critical patent/CA1187128A/en
Expired legal-status Critical Current

Links

Classifications

    • FMECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F16ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
    • F16JPISTONS; CYLINDERS; SEALINGS
    • F16J15/00Sealings
    • F16J15/16Sealings between relatively-moving surfaces
    • F16J15/34Sealings between relatively-moving surfaces with slip-ring pressed against a more or less radial face on one member
    • F16J15/3404Sealings 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
    • F16J15/3408Sealings 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
    • F16J15/3412Sealings 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
    • F16J15/3416Sealings 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 at least one continuous groove

Landscapes

  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mechanical Sealing (AREA)
  • Structures Of Non-Positive Displacement Pumps (AREA)

Abstract

ABSTRACT OF THE DISCLOSURE

A seal assembly of the mechanical face seal type has features to reduce leakage across the faces. The seal assembly includes a stationary seal ring through which a rotating shaft passes. A rotating seal ring is mounted around the shaft for rotation therewith. A spring urges the rotating seal ring into contact with the stationary seal ring. A plurality of concentric, nonintersecting grooves are placed on the face of the stationary seal ring to enhance sealing.

Description

_CKGROUND oF THE INVEN~ ON

Large volume su~mersible pumps, cornmonly us~d ir. oil well production, have a submersible electrical. motor knat rotates a shaft. The sllaft extends through a seal sec-ti.on into a centrifugal pump for rotating the pum~. In the seal sectlon, there are several parti~ions through which the shaft passes.. At the entranc~ and exit of ~he seal section and in the partitions, mechani.cal face seals are mounted to seal the interior from exterior well fluid.
A t~pical rnechanlcal ace seal has an annular stationar,y m~mber that is mounted to the wall structure.
A rotatiny seal mem~er is coupled to th~ shaft to ro~ate with the shaft. The rotating seal member has a face that is urged into contact witll the stationary face by means of a coil spring. ~ pressure compensator in the motor secti.on or seal section provides a low pressure differential between the interiox lubricant and the exterior well fluid. The seal membexs reduce lubricant leakage to the exterior, and well fluid leakage into the pump ~rom the ex~erior.
Normally, the faces of the rotating and stationary seal rings are planar, smooth surfaces. For differing reasons, proposals have been made in the prior art -to apply various configurations of grooves to the faces of mechanical face seals in general.

7~

_I ARY OF THE INVENTION

In this invention, the seal assembl~ has a stationar~
seal ring rixe~ to ~all structure. A ro-ta-tillcJ sea1 ring is fixecl to the s~laft for rotation therewith. A spring uryes the rotating sea:L ring into rota~inc3 contac-t with the stationary seal ring. The stationar~ face has at least one concentric groove formed in it. This groove is e~ty, and defines a closed annular cavity in contact wi-th the opposite face. Preferably a nun~ber of concentric grooves, each spaced apart by planar annular surfaces, are located on the stationary face.

~ ~ ~7~
'I
~I~IEI;' D~SCRIl''rlON Ol''r~l~ Di~Ai~lNGS

i~'iq. 1 is a view of a seal asciembly constructe~ in accordance ~lith thi.s invention.
Fiy. 2 is a view of the seal assembly oE E~iy.
mounted in a submersible pump.
Fiy. 3 is a view of th~ ~ace of ~he sta~ionary seal ring of the seal assernbly of Fig. 1.
Fiq. 4 is a sectional view of the s~ationa~y seal ring of ~he seal assembly of Fig. 1, taken alonq the line IV-IV of Fiq. 3.

7~

Dli,'SCl~lPTLON O~ TIIE. PRE:E`l:RR~D EMB()DI~I-ENT

Referring to Fi~. 2, a submersible pump lL is show~
partially. Suhmercible pump 11 includes an electrical motor 13 wAich rotates a shaft 15. Shaft 15 extends throuyh a seal sec~ion 17 and i~to a cen-trifugal pump 19.
A number of partitions 21 are located in seal section 17, definin~ separate chambers. Mechanical fac~ seal assemblies 23 scal the sha~t 15 at each parti~,ion and also at the ends of the seal section. The motor 13 and the seal sec~ion 17 are filled with a lubricating oil. A
~ellows 25, shown located below motor 13, equalizes the pressure of the interiors of the motor 13 and seal section 17 with ~.he exterior well fluid pressure, Some or all of thc partitions 21 and ends of seal section 17 will have seal assemblies 23 as shown in Fig.
1. Each partition 21 and end of seal section 17 has a passage 27 exten~ing through it for receiving shaft 15.
Bushings (not shown~ are located in the passage 27 to serve as bearings and maintain shaft 15 in alignment.
A stationary seal ring 29 is mounted at th~ entrance of passaye 27 of the wall structure or partition 21. The exterior of stationary seal ring ~'3 is sealed by an O-riny 31. Stationary seal rinc~ 29 is of a hard material such as cera~ic. Stationary seal ring 29 has a face 33 that faces away fxom passa~e 27. A5 shown in Figs. 3 and 4, face 33 is planar and free of any cavities but for a plurality of grooves 35 formed in the face. Grooves 35 are concentric with the axis of stationary seal ring 29. Grooves 35 are shown yenerally squarc in transverse cross-section although this is not essential. The width at the surface o~ ea-h yroove 35 i~ about the same as -~he dep~h. ~lso, the land 37, which is the annular planar surface betwe~n each groove 35, is about the same radial width as the radial width of ea h groove 35. Face 33 is free of any channels, passages or yrooves other than groove 35, so ~hat each groo~ 35 is ~ closed circular channel free of intersections With other cavities.

~8~

Grooves 35 al^e very sm~lll in radial wid-th and very shallow. l~owever, the ~:aclial ~1id-th of groove 35 ~hould be ' no smallt~r than the ~hickness of the fluid flim betw~en station.lry se.~i rirly 2'3 and rotatin(~ al ring 39.
Althouyh t}le rotating ring of a mechanical seal is urged into contac~ ~ith the stat:ionary face, modern seals are desi,yned such that a very thin fluid film is maintc-~irlfcl between the faccs to prevent wear. The thickness of thi~
fi,lM is of the order o~ 0.0001 inch. The upper lirllit o~
the groove wid~,h an~ dep~h is not critical, but ~ust be within practical limits for ease in manuracturing and use, and allow th~ normal limits of face pressure for mechani~:al face seals.
The other portions of seal assembly 23 are conventional. These portions include a rotating seal ring 39 that is softe~r than ~tationary seal ring 29 al,d preferably carbon. Seal ring 39 has a planar, smooth face ~hat rotates in sliding contact against the facc 33 of ~he stationary seal ring 29. Contact of rotatincJ sc.ll rincJ 39 against face 33 results in an empty, closed annular s~ace at each groove 35. The rluid rilm between the f~ces is prevented from leaking into the grooves by the action of surface tension forces. A collar 41 s~cures an clastomeric boot 43 to rotating seal ring 39. Boot 43 fits tightly around shaft 15 to provide sealincJ. The inner diameter of rotating seal ring 39, as well as the inner diameter of stationary seal ring 29, is larger than the diameter of the shaft 15, providing a clearance. ~oot 43 seals liquid from passiny through these clearances. A
coil spring 45 is compressc~ bet~t~en collar 41 and a circul~r flan~e 47. ~ ret~linir,g ring ~19 in a groove ir:
shaft 15 locate~. flc.nc3e 4~.
Coil spring 45 will exert a force against rotating seal ring 39, which presses against stationary seal riny 29, resulting in a face pressure that is the force divi,ded by the contacting surface areas of seal rinys 29 and ~9.
Coil spring 45 is conven~ional,ly sized t,o provide 10 to 40 psi (pounds per r,q-lare inch) pressure of rota-ting seal y~

r ny 39 clgainst sta~ionary seal rin~ 29. The op~imu~n range is 20 to 3U psi, pre.l~erihl~ 24 L)ii.. Mi.n:Lmul~ ~tn maXi~lllm face r~ressures can al~;o ta~.c :into (~c~co~ t rOtatiOrlal Sr)e~'d',. ~t c`l t`,~pical. .^,t.ltior~]. .;E)~e~ ~ 3~l50 revolution s ~jeL min~lle, thc: m.i n il~nn; ~n~ mums ~ re .'35 psi foot/c;ec. (l-,oun-l~ pcr square inC}I X f~et C3:LVi.CleCI '~y seconds~, arld '3~ psi -feet/~.;ec. fo;- a ceranlic stal:iGIlary seal rincJ 29 and carbon rot.atin~ seal rinc~ 39. Gencra~ly, h.,gher rotational speeds require 1ess spring ~orce than lower speeds.
Th~ rnaximum r;umber and ~axirnum widths oE cjrooves 35 must not cause the face prcssures to exceed the maximum limits mentioned. Grooves 35 reduce the contactin~
surface area of seal rings 29 and 39, and thus increase the pressure for a selected sprinc3 45. For a low pressure lS differential acros.s the .seals of less than 5 psi, a .. ingle cJroov~ 35 is 1~a~i~1e ~Jith a radic~l width ~rom 0.003 to 0.020 inch for a contacting face 39 with a radial ~liclth of 0.1.]5 inch. For hi~her ~iffcrential prcssure, 5~20 psi, a plurality of concentric grooves is preferably used with radial widths preferably from 0.003 to 0.005 inch for the same face widthx. The preferred depth of grooves 35 is 0.005 inch. Each land 37 is pr~ferably 0.005 to O.OlO
inch in radial width. The number of grooves 35 may feasibly range from about l to 14, preferably 8-14, for th~ above dimension of seal face 39. ~ preferrecl seal 29 for the above face dimensions of seal rin~ 39 has ei~ht yrooves 35 of 0.005 inch width with lands 37 of O.OlO inch wldth.
In operation, motor 13 will r(j-tate shaft 15, which in turn rotates pump l9. Normally a mix-ture of oil and water will ~e :locatecl on the cxterior of seal sec~.ion 17, with lubricant in the interior~ Bellows 25 will reduce the pressure clifferenti.al. between the interior and the exterior. Rotating seal ring 39 will rotate in unison with shaft lS, while s~ation~ry seal ring 29 remaills fixcd to partition ~l. The sl:iding contact of the faces of the rotating seal rinc~ 39 and stationary seal ring 29 serve to '7~

reduce leakage of lubricant past the seal assembly ~ o thc exterior sholll,d internaL pressure e~:ce~cl ~he ~:t~r;la' pressure. Also, thc COl'lt.lC'ti,I'.CJ Laces of the statiOr.~fy seal rin~ 2~ .~nd rotatinJ seal ring ~9 se~rve to recillce leakage of well Eluicl into ~he interio~ of -the ~eal section 17 should the external pressure exceed -thc internal pressure.
I,aboratoLy tes~,i.ng has indicated that the (3rooves 35 enhance the ability oE the seal assembly to p~event leakage. Testing indica-tes tha~ leakage of well 11uid into the seal' section may be completely eliminate~ for a fairly lon~ durat:Lon, while conventional mechanical Eace scals always leak ~o some extent. The reasons ~or ~he irnproved resu~s are not completely underst,,oc,~. ro,si}~l,y the grooves provide a gas trap, improved lubricating of the contactinc~ faces, or a mearls to produce a uni~orm circular path fluid as opposcd to the random flow movelllent in conventional seal faces, or a combination of all of these.
The invention has significant advantages. The grooves enhance sealing, reducing the entry of well fluid in~o the seal section and thc egress of lubricant. This may increase the duration that a pump can operate without removing the pump ~or maintenance.
While the invention has been shown in only one of i-ts ~orms, it should be apparent to those s~illecl in the art that it is not so limited but is suscep~ible to various changes and modi L ica~ionc; without departing frorn thc spirit o~ the invention.

.. .. . . .

Claims (3)

The embodiments of the invention in which an exclusive property of privilege is claimed are defined as follows:
1. In a seal assembly for a rotating shaft having an axis and extending through wall structure, the seal assembly having a stationary seal ring with a circular face with a flat surface and carried stationarily by the structure, a rotating seal ring carried by the shaft for rotation there-with and having a circular face with a flat surface, and spring means for urging the flat surfaces of the faces into engagement with each other, the improvement comprising:
at least one circular groove concentric with the axis of the shaft and recessed within the flat surface of the face of the stationary seal, the groove being free of intersections with any cavities in either face to define with the rotating face a closed, annular space.
2. An improved seal assembly for sealing around a shaft having an axis and passing through a wall structure, comprising in combination:
a stationary seal ring having a circular face and fixed to the wall structure;
a rotating seal ring carried by the shaft for rotation therewith, the rotating seal ring being of a material that is softer than the material of the stationary seal ring and having a circular face; and spring means for urging the face of the rotating seal ring into rotating engagement with the face of the stationary seal ring;
the stationary face having recessed within it a plurality of non-intersecting circular grooves concentric with the axis of the shaft and defining with the rotating seal face a plurality of closed, annular cavities substantially free of liquids, each groove being separated from other grooves and encircled by circular lands which have flat faces that are located in a single plane perpendicular to the axis of rotation and which are engaged by the face of the rotating seal ring.
3. In a submersible pump of the type having a motor with a rotating shaft having an axis and extending through a seal section to drive a centrifugal pump, an improved seal assembly for preventing leakage around the shaft, comprising in combination:
a stationary seal ring fixed to the seal section, the stationary seal ring having a circular flat planar face containing a plurality of circular grooves recessed within and concentric with the axis of the shaft, each groove being separated from the other grooves by circular planar surfaces, the grooves being free of intersections with any cavities;
a rotating seal ring carried by the shaft for rotation therewith, the rotating seal ring being of a material that is softer than the material of the stationary seal ring and having a flat planar face; and spring means for urging the face of the rotating seal ring into rotating engagement with the face of the stationary seal ring;
the area of the engaging surfaces of the rings and the force of the spring means cooperating to provide a face pressure in the range from 10 to 40 psi.
CA000410428A 1981-12-23 1982-08-30 Grooved mechanical face seal Expired CA1187128A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US33402181A 1981-12-23 1981-12-23
US334,021 1981-12-23

Publications (1)

Publication Number Publication Date
CA1187128A true CA1187128A (en) 1985-05-14

Family

ID=23305224

Family Applications (1)

Application Number Title Priority Date Filing Date
CA000410428A Expired CA1187128A (en) 1981-12-23 1982-08-30 Grooved mechanical face seal

Country Status (3)

Country Link
CA (1) CA1187128A (en)
DE (1) DE3239465A1 (en)
GB (1) GB2112087B (en)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4936197A (en) * 1988-10-12 1990-06-26 C. E. Conover & Co., Inc. Dynamic seal construction
DE3936520A1 (en) * 1988-11-02 1990-05-03 Tokai Rika Co Ltd Vehicular electrically heated external mirror connection package - has groove around resin filled space enclosing conductive terminal elements in housing of heater mounted connector
GB9606815D0 (en) * 1996-03-30 1996-06-05 Crane John Uk Ltd Mechanical face seals
CN102386712A (en) * 2010-09-01 2012-03-21 中国北车集团大同电力机车有限责任公司 Sealing device for traction electric machine
CN104500749A (en) * 2015-01-12 2015-04-08 大连华阳密封股份有限公司 Mechanical seal suitable for film evaporator
CN109654228B (en) * 2018-12-07 2023-09-08 宁波方力密封件有限公司 Dry grinding mechanical seal assembly

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB483280A (en) * 1936-03-27 1938-04-12 George Patrick Gilman Improvements in or relating to a sealing device for rotating shafts

Also Published As

Publication number Publication date
GB2112087A (en) 1983-07-13
DE3239465A1 (en) 1983-06-30
GB2112087B (en) 1985-11-13

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