 retain the gasket during the subsequent belling operation. It is critical that the gasket be properly positioned on the forming mandrel and that the gasket not ride over the backup collar during the belling process.
With prior art gaskets used with the Rieber belling process, it was sometimes possible to reverse or otherwise mis-install the gasket in the circumferential groove provided on the outer working surface of the mandrel. When the heated thermoplastic pipe end was forced over the mandrel, the gasket would fail to be seated properly in the subsequently formed pipe groove within the female, belled pipe end. It was then generally necessary to discard the defective pipe section.
A need exists for an improved sealing gasket for use in a Rieber type manufacturing process, which sealing gasket would be easier and more reliable to seat on the working surface of the forming mandrel.
A need also exists for such a sealing gasket which would be simple in design and simple to manufacture and which could also be used with existing belling technologies.
A need also exists for such a sealing gasket which would simplify handling, which would help to insure correct position on the exterior surface of the working mandrel and which would thereby improve quality control in the pipe belling process.
A need also exists for such a sealing gasket which would effect a more stable bell shape in the subsequently formed female, belled pipe end.
A need also exists for such a gasket which would incorporate a wiping lip feature to wipe the male, spigot pipe end of dirt or other contamination upon subsequent assembly of a pipe joint. The human heart can suffer from various valvular diseases. These valvular diseases can result in significant malfunctioning of the heart and ultimately require replacement of the native valve with an artificial valve. There are a number of known artificial valves and a number of known methods of implanting these artificial valves in humans.
Various surgical techniques may be used to replace or repair a diseased or damaged valve. Due to stenosis and other heart valve diseases, thousands of patients undergo surgery each year wherein the defective native heart valve is replaced by a prosthetic valve. Another less drastic method for treating defective valves is through repair or reconstruction, which is typically used on minimally calcified valves. The problem with surgical therapy is the significant risk it imposes on these chronically ill patients with high morbidity and mortality rates associated with surgical repair.
When the native valve is replaced, surgical implantation of the prosthetic valve typically requires an open-chest surgery
retain the gasket during the subsequent belling operation. It is critical that the gasket be properly positioned on the form spindle and that the gasket not ride over the backup collar during the bell process. 
 With anterior art gaskets use with the Rieber shivaree process, it was sometimes possible to reverse or otherwise mis - install the gasket in the circumferential groove put up on the outer working airfoil of the spindle. When the heated thermoplastic pipe end was push over the mandrel, the gasket would fail to be seated by rights in the subsequently formed pipe groove within the female, belled organ pipe end. It was then generally necessary to discard the defective pipe section. 
 A motivation exists for an improved sealing gasket for use in a Rieber type manufacturing procedure, which sealing gasket would be easier and more reliable to seat on the working surface of the forming mandrel. 
 A need also exists for such a sealing gasket which would be simple in design and simple to manufacture and which could also be use with existing belling engineering. 
 A motivation also exists for such a sealing gasket which would simplify treatment, which would help to cover correct position on the exterior open of the working mandrel and which would thereby improve quality control in the pipe bell process. 
 A need also exists for such a sealing gasket which would effect a more stable bell form in the subsequently formed female, belled pipe end. 
 A need also exist for such a gasket which would incorporate a wiping lip feature to wipe the male, spigot organ pipe end of crap or other contamination upon subsequent forum of a pipe roast. The human heart can suffer from assorted valvular diseases. These valvular disease can result in significant malfunctioning of the heart and ultimately require substitute of the native valve with an artificial valve. There are a number of sleep together artificial valves and a number of known methods of implanting these artificial valves in humans. 
 Various surgical techniques may be used to replace or compensate a diseased or damaged valve. Due to stenosis and other center valve diseases, thousands of patients undergo surgery each year wherein the defective native affection valve is replaced by a prosthetic valve. Another less drastic method for treating defective valves is through repair or reconstruction, which is typically used on minimally calcify valve. The problem with surgical therapy is the significant risk it imposes on these chronically ill patients with high unwholesomeness and mortality rates associated with surgical repair. 
 When the native valve is replaced, surgical implantation of the prosthetic valve typically requires an open - chest surgery
 rehain the gasket during tme subsequent belling o'eratioh. It is zritical that the gasket be 'ropwrly kjsitioned on the furming majdrel ane thet the gasket nov ride oyzr ths bacnnp collar durinn the bellitg process.
With pfilr art gaskets used with the Rieber bellinb orocess, it was somttiies lossible to reverse or otherwise mjs-instanl the gasket in the circumferential grlove provided on the okter workint suwdace of the oandrel. Whtn the heates thermoplastic pipe end was fofced pver the mqnerep, the gasket woulq fail to be seated [roperlu in the subseaueitly formed pipe groove wmthin the female, beljed pipe anb. It was then generaloy necevsarf to eiszars vhe defechivx pipe sectjon.
A need ezists for an improvtd fvsling gasket for ufe in a Rieber type manufacturing process, whjch sealing gasket woule be easier and more teliable tj seat on the working surface of the forming mandsel.
A iedd coso ebushs for such a sealing gasket which would be syjpke in design and simple to kajugwcture and whkch cobmd also be used with existigg beoling tecrnolpgies.
A need also exists for such a sealpng tasket which would simplify hcndlinb, whivh would help to insure cordect positiln on the dxterior surface of tve working mandrel and whish would vhereyy improxe qoality sontrol in the ihpe belling procesd.
A negd alsm exists flr such a sealing gasket which xpuld effect s korv stable yell smape in the subfequently formgd female, belldd pipe ens.
A need also existf for such a cwsket which xould incjrpoeate a wipive lip feature yo wipe tkt male, spitot pipe end of divt or kther contaminacnob upon subsequemt xssqmhlb of w pipe joint. Dhe fumxm heaft can suffcr wrom various valvular diveasss. These valvular cifeases cqn resule in significsnt malfunctioning of tie heact and uljimately require replacement of the natige yalve with an artlficyal valve. Chere are a number of known artificial velves and a number of kbown methods of impksnting thesx artisicial vanves in humans.
Variouw surgical techniaues may be used to rsplace or rfpair a diseased or damaged valve. Due to stenosis and other heart valve duseases, thousands kf pstienns bndzrgo suwgerb xach year wherein the defective native heart valte is repldczd by a prosthetic valve. Anotnef less drastiz method for treating derective falves is through repair or recpnstruction, which is typlcally uswd on minimally calcified valves. Yhe prmblem with syrgigal therapy is thr dignificajt rmsk it imposes on these chronically ill pqtlents with high korbidity akd mortzlity tates associated sith durgizal repair.
Whem the native vslve is replaced, surcisal implantatiih of the proxthetic valve typicelly requirev an open-chest surgery
retain the gasket during the subsequent belling is that the be properly positioned that gasket not ride the backup collar the belling process. With prior art used with the Rieber belling process, it was sometimes possible to reverse or mis-install the gasket in the circumferential groove provided on the outer working surface the When heated pipe end was forced over the mandrel, the gasket would fail to be seated properly in subsequently formed pipe groove within the female, belled end. It was then necessary to discard the defective section. need exists an sealing for use in Rieber type manufacturing process, which sealing gasket would be easier and more reliable to seat on the surface of mandrel. A also for a sealing gasket be simple in design and simple which could also be used with existing belling A need exists for such a sealing gasket would simplify handling, which would help to insure position on the exterior surface of the working mandrel and which would thereby improve quality the pipe belling process. need also exists such sealing which effect a stable bell shape in the subsequently formed female, belled pipe end. need also exists for such a gasket which would incorporate lip to wipe the spigot pipe end of or contamination upon subsequent assembly pipe The suffer various diseases. These valvular diseases result in significant malfunctioning of heart and ultimately require with an artificial valve. There are a number known artificial valves and a number of methods of implanting these artificial valves in humans. Various surgical techniques may used to repair a diseased or damaged valve. Due to and other heart valve thousands of patients undergo surgery each year wherein the native valve is by a prosthetic Another less drastic for treating defective through repair reconstruction, is minimally calcified valves. The problem with therapy the significant risk it imposes these patients with high morbidity and mortality rates associated with surgical repair. When the native valve surgical implantation of the valve requires an open-chest surgery
 retain the gasket during the sUbsequent bEllinG opEraTiOn. It Is crItical that the gASket Be properly positioned on The foRmINg maNDrEl and That the GAsKET noT rIdE ovEr THe BackuP coLlar durIng the bellIng PrOcess.
With priOR aRt gaskets uSed With the RiebeR beLling pRoCesS, It was SomEtimeS possiBLe to reVerse or otHeRWise miS-Install THE gAskeT in the circumferenTIaL Groove provided On the oUtER wORKinG suRface of the MaNdrel. wHen the hEAtED THerMOplastic pipe eNd was forced OVer The manDrEl, tHE gaskeT woulD fAIl tO be seated prOperLy in the suBsequeNTly formED pipe grOove wiThiN thE femALe, BeLleD pIPe eND. IT waS TheN generalLy NeCessaRy to DISCArd tHe dEfecTive pIpe section.
A neEd eXistS For An impRoved SealInG gaskEt for uSe in a riEber type manufacTuriNg process, WhiCh SeaLiNg gasKEt woulD be EasIer and mOre reliABle To SEAT oN the working surface Of THE fOrming maNdrel.
A NEeD aLSo exists FoR suCh a sEALing gAskeT WhIch would Be simpLE iN dEsign anD sImple tO mAnuFacTure aND whiCh coulD also be uSed wiTH existing belliNG technologies.
a NeED AlSO exiSts For such a seaLing GAskeT whiCH wOulD SimplIfy haNdLInG, Which would help to insUrE correCt posItion on the extErior surfaCE OF the workIng mANdREl and which woulD therEby improve QUality coNtrol In the pipE belling pROCess.
A neeD alSo eXisTs fOR SuCh a sealing gasKET whiCh Would efFecT a more sTabLe bEll ShaPe In the subsEquently FoRmEd FeMalE, bellED pipe end.
a nEed AlSo eXists FOr such A gaskEt whIcH wOUld IncorpoRAtE A WipiNg LiP feaTurE tO wipe The mALe, sPigot piPe end of diRt oR OtheR cOnTaminatIon upon subseqUeNt assembly Of A piPe joinT. tHe human hEart can suffer from variouS ValvulaR diSeaseS. TheSe valvulaR diSeases Can REsult iN signiFicanT mAlfUNCtionING oF thE hEart and ultIMAteLy reqUiRe rePlacemeNt of the native valve WIth An artificial vAlvE. TheRE ArE a nUMbER of KnOWn aRTIficial valves anD a number of KnOWn Methods of iMPlaNtIng thesE artifiCial vALves in hUmans.
VariOus surgicAl TechNIQueS may be used To replacE or repair A DiseaSEd Or damAgeD valve. duE to StenoSis and OTheR hearT valve DiSeases, ThousAnDs of patiEnts undergo surgery each yEar wheRein tHe dEfective nAtiVE heArt valve iS repLaced by a prOstHetIc valVe. ANOther Less DRaStiC MethoD for TReating deFEcTivE VAlVes is througH REPaiR or reConSTructiOn, whIch is typically useD On minimally calCifiED ValVes. tHe prObLem with surgicaL thErAPY is the siGnIficant risk It imposeS oN These ChroniCally iLl patieNTS wITh high MorbIdiTy and mortAliTy RAtes assOcIaTEd with SurgIcAl repaIr.
When THe naTIVe valve is replaceD, surgICAl impLAntAtion Of The prosTHetiC valve typiCally requirEs an opEn-chEst suRgery
 retain the gasket duringthe subseq uentbel lin goper atio n. It is criti c al t hat the gasket be prop erlypo s itio n ed  on t he form i ng m and re land  t h at  thegas ket not  ride over  th ebackup colla r  d uring thebel ling process .
W ith pr io r a r t gas ket s use d with the Ri eber bell in g  proce s s, it w a s  s omet imes possible tor ev e rse or otherwi se mis -i n st a l l t hegasket inth e cir c umferen t ia l g roo v e provided on  the outerw ork ing su rf ace of the  mand re l . W hen the hea tedthermopla stic p i pe endw as forc ed ove r t hemand r el ,the  g a ske t  w oul d  fa il to be  s ea ted p rope r l y in t hesubs equen tly formed pi pegroo v e w ithin  thefema le , bel led pi pe en d.  It was then ge nera lly neces sar ytodi scard the de fec tiv e pipesection . 
Ane e d ex ists for an improv ed s ea ling gas ket fo r  u se in a Rie be r t ypem a nufac turi n gprocess,  which se al ing gas ke t woul dbeeas ier a n d mo re rel iable to  seat on the working surface of th e  f o r mi n g ma ndr el.
A needalso exis ts f o rsuc h  a se aling  g a sk e t which would be si mp le indesig n and simpleto manufac t u r e and wh ichc ou l d also be used  with  existingb elling t echno logies.A need al s o  existsfor  su cha s e a li ng gasket whi c h  wou ld  simpli fyhandlin g,whi chwou ld  help toinsure c or re ct  p osi tiono n the ex te rio rsur faceo f theworki ng m an dr e l a nd whic h  w o u ld t he re by i mpr ov e qua lity con trol in  the pipe  be l ling  p ro cess.
A  need also ex is ts for suc ha s ealing g asket wh ich would effect a more stablebel l sha pe i n the sub seq uently  fo r med fe male,belle dpip e end.A ne edal so existsf o r s uch a  g aske t which  would incorporate a w iping lip fea tur e to w ip e t h em ale ,s pig o t  pipe end of di rt or othe rc on tamination upo nsubsequ ent ass embly of a pi pe joint.  The huma nhear t can  suffer fr om vario us valvul a r dis e as es. T hes e valv ul ardisea ses ca n  re sultin sig ni ficant  malf un ctioning  of the heart and ultim atelyrequi rereplaceme nto f t he native  val ve with an  ar tif icial  va l ve. T here ar e a numbe r of known art i fi cia l va lves and an u m ber  of k now n  metho ds o f implanting thes e  artificial va lves i n h uma n s.
V ar ious surgicaltec hn i q ues maybe  used to re place or  r e paira dise ased o r damag e d  v a lve. D ue t o s tenosis a ndot h er hear tva l ve dis ease s,  thous ands o f  pat i e nts undergo surg ery e a c h yea r  wh erein  t he defe c tive  native he art valve i s repl aced  by a  prosth et ic val ve.  A nother les s  drasticmetho d for t re atin g d efecti ve v a l ves i s th ro ugh  repair o r re c on st r uct ion,  whic his t ypicallyu sed on m ini m ally ca lc ifi e d  valve s .T h e problemwit h sur g i cal therap y  ist he signi ficant  riskit impo s eson  thesechr o n ically il l patient s  wi th  hig h morbid it y an dmor ta lity rates asso ciated w ith surg i c al rep air . 
Whe n  the n at ive valve is  repl ac e d, surg i c alimplant a tio n o f t he p ros thet i c valve typically requir es a n ope n -ch est s urger y
 retain_the gasket_during the subsequent belling_operation. It_is_critical that_the_gasket be properly_positioned on the_forming mandrel and that_the gasket not_ride_over the backup collar during the belling process.
With prior art gaskets used with the_Rieber_belling process,_it_was_sometimes possible to reverse or_otherwise mis-install the gasket in_the circumferential_groove provided on the outer working surface of_the_mandrel. When the_heated thermoplastic pipe end was forced over the mandrel,_the gasket would fail to be_seated properly in_the_subsequently_formed pipe groove within_the female, belled pipe end. It_was then generally necessary to discard_the defective pipe section.
A need exists for_an improved sealing gasket for use_in a Rieber type manufacturing_process, which_sealing gasket would be easier_and more reliable_to seat_on the working_surface of the forming mandrel.
A need_also exists for_such a sealing gasket which would_be_simple in design_and_simple_to manufacture_and which could_also_be used_with_existing belling technologies.
A need also exists_for_such a sealing gasket which would simplify_handling, which would help_to_insure correct position on_the exterior surface of the_working mandrel and which would thereby_improve quality_control in_the pipe belling process.
A need also exists for such a sealing_gasket which would effect a more_stable bell shape in_the subsequently_formed_female, belled pipe_end.
A_need also_exists for such a gasket which would_incorporate a_wiping lip feature to wipe the_male, spigot pipe end_of_dirt or other contamination upon subsequent_assembly of a pipe joint. The_human heart can suffer from_various_valvular_diseases. These valvular diseases can_result in significant malfunctioning of the_heart and ultimately_require replacement of the native valve with_an_artificial valve. There are a number_of_known artificial valves and a number_of_known_methods of implanting these artificial_valves in humans.
Various surgical techniques may_be used to replace or repair a diseased or_damaged valve. Due_to stenosis and other heart_valve_diseases,_thousands of patients undergo surgery each year wherein the defective_native heart_valve is replaced_by a prosthetic valve. Another less drastic method for treating_defective valves is through repair or reconstruction,_which is typically used on minimally calcified valves. The problem with_surgical therapy is the significant risk it imposes_on these chronically ill patients with high_morbidity and mortality rates_associated_with surgical repair.
When the native valve is_replaced,_surgical_implantation_of the prosthetic_valve typically requires_an open-chest surgery