Iminyaka eminingana ama-fluoropolymers abambe iqhaza elibalulekile ezimbonini zamakhemikhali nezifanayo ukuze kuvikelwe izitshalo nemishini ekuhlaselweni kwamakhemikhali ngohlu olubanzi lwemithombo yezindaba enolaka.Lokhu kungenxa yokuthi zinikeza ukumelana kwamakhemikhali okungcono kakhulu kanye nokuzinza kokushisa kunamanye amapulasitiki noma izinto ze-elastomeric. Sekuyiminyaka eminingana ama-fluoropolymer abambe iqhaza elibalulekile ezimbonini zamakhemikhali nezinye ezifanayo ukuvikela izitshalo nemishini ekuhlaselweni kwamakhemikhali ngezinhlobonhlobo eziningi ezinolaka. abezindaba.Lokhu kungenxa yokuthi banikeza ukumelana kwamakhemikhali okungcono kakhulu nokuzinza kokushisa kunamanye amapulasitiki noma izinto ze-elastomeric.
Ngemva kokuthuthukiswa kwe-PTFE, ukwethulwa kwe-melt-processable fluorinated ethylene-propylene (FEP) ngo-1960 kwavula izindawo zokufaka izicelo ezintsha ngokuphelele.I-PFA, i-polymer ye-perfluoro-alkoxy esetshenziswe ngempumelelo iminyaka engu-20 njengendwangu yendwangu, manje isilandela i-thermoplastic ku-PTFE, enokumelana okulinganayo okushisayo namakhemikhali kanye nezakhiwo eziphakeme maqondana nokucutshungulwa, ukuguquguquka, ukumelana nokuvuzwa kanye namandla omshini. .
Embonini yamakhemikhali, kokubili ama-fluoropolymers - PTFE kanye ne-PFA - asetshenziswa ikakhulukazi ngendlela yama-linings.Ukuze uthole izimo ezilula, ezifana namapayipi, ukugoba, izingcezu ze-T noma amalunga okunciphisa, i-PTFE ivame ukusetshenziswa;isetshenziswa ngendlela yokunamathisela i-extrusion, i-ram extrusion noma i-tape wind-ing.Kulezi zinqubo i-pre-form yenziwe ye-PTFE;lokhu kube sekufakwe i-sintered futhi kufakwe kucwecwe lwensimbi.Ukusebenzisa i-PTFE ulwelwesi lwezingxenye zensimbi zomumo oyinkimbinkimbi, njengamavalvu namaphampu, kunzima kakhulu.Ukubunjwa kwe-Isostatic ke kuyindlela ekhethwayo.Kule PTFE powder igcwaliswa esikhaleni esidalwe phakathi kwensimbi yokusebenza kanye nesikhwama senjoloba esenziwe ngokukhethekile ukuze singene esimweni sendawo ezofakwa ulayini.Impushana icindezelwa ngaphambili, bese icindezelwa ngokubanda ibe yisimo esifisayo.Ekugcineni, isikhwama senjoloba siyakhishwa bese ingxenye elayishiwe ishiswa kuhhavini ongaphezu kuka-360?C (680?F).
I-PFA, impahla ye-thermoplastic enephuzu lokuncibilika elichazwe kahle, ingacutshungulwa ngendlela yokudlulisa ukubumba noma ukubumba umjovo.I-granulate iyancibilika ebhodweni elincibilikayo noma ku-extruder bese iphoqelelwa ethuluzini elishisayo ngomshini wokucindezela we-hydraulic.
Le ndlela yenza ukuba ukujiya kodonga okunembe kakhulu kuzuzwe, ngokubekezelela ?0,5 mm, ngisho nakuma-radii aqinile nakuma-undercuts.Empeleni akukho ukuqeda ngomshini okudingekayo, ngaphandle kokukhipha umhluzi nokushelela ubuso bokuhlangana kwama-flange.
Uma usebenzisa ukubunjwa kwe-isostatic, nokho, inani elikhulu lokuqedwa komshini liyadingeka - kuye ngezinga lenkinga yomumo okufanele ugcwaliswe - ukufeza ubukhulu obufunwayo ngokunemba.
Ukulingana kokuqina kodonga kungase kuhluke kakhulu, ikakhulukazi esimweni somumo oyinkimbinkimbi njengama-valve housings.
Ukumuncwa kanye ne-Permeation
Ngokungafani nezinsimbi, amapulasitiki nama-elastomer amunca amanani ahlukahlukene emidiya ahlangana nawo.Lokhu kuvame ukuvela kuma-organic compounds.Ukumuncwa kungase kulandelwe ukungena odongeni.Nakuba lokhu kungavamile ukubonwa ngama-fluoropolymers, kungamelana nokuqina kodonga okwandayo noma ngokufaka amadivaysi ukuze kukhishwe isikhala phakathi kolwelwesi lwe-fluoropolymer nodonga lwensimbi.Kuboniswe ngokusobala ukuthi maqondana nokungena nokumuncwa, ama-fluoropolymer acutshungulwe ancibilika njenge-PFA abonisa izakhiwo zokuvimbela ezingcono kune-PTFE.
Vacuum Ukumelana
Ukumelana ne-vacuum kuyadingeka ngoba, ezinhlelweni ezivaliwe zohlobo olusetshenziswa kabanzi ekucutshungulweni kwamakhemikhali, ukwehla kwezinga lokushisa kudala i-vacuum ohlelweni, ngaphandle uma selivele lisebenza ngaphansi komfutho womoya.Uma usebenzisa i-PFA kulula ukufeza ukumelana ne-vacuum okwanele kolwelwesi.Ngokuvamile ulwelwesi ?luqinisiwe?odongeni lwensimbi ngokusebenzisa ?umsila wejuba?ama-grooves noma iziteshi ku
kamuva.
Nge-PTFE granulate eye yabanda-yakheka, kunzima kakhulu ukufeza ukubambelela komsindo kolwelwesi odongeni lwensimbi njengoba kungadingeka amashaneli amakhulu ukuze kuvunyelwe i-PTFE powder ukuthi igeleze ingene emifantwini.Ngokujwayelekile, ngakho-ke, ama-bonding agents asetshenziswa phakathi kolayini lwe-PTFE kanye nezindlu zensimbi.Kodwa-ke, ngenxa yezici zokulwa nokunamathelayo zama-fluoropolymers kanye nokumelana nokushisa okulinganiselwe kwama-ejenti ama-bonding, i-PTFE ikhombisa ukumelana ne-vacuum okulinganiselwe kuphela.
Ukulawulwa Kwekhwalithi kuvimbela imifantu nama-Voids
Nge-PTFE kanye ne-PFA linings, amandla e-dielectric akalwa ukuze kuhlonzwe amaphutha.Le ndlela ikhomba ngokuthembekile imifantu kanye nama-voids ahamba yonke indlela ngokusebenzisa impahla kodwa, ngenxa ye-resistive ephezulu eyaziwayo yama-fluoropolymers, ayibonisi noma yimaphi amaphutha aqala ngo-1,5 mm noma ngaphezulu ngaphansi komhlaba (umkhiwane 5) .
Ngalesi sizathu ezinye izivivinyo kusetshenziswa izindlela ze-ultrasonic nazo zingasetshenziswa.Lokhu kuhlola kukala ibanga ukusuka ebusweni bolwelwesi kuya endlini yensimbi.Kodwa-ke, ayithembekile ngoba ayinikezi ukujiya komugqa wangempela lapho i-void noma i-porosity ikhona.Ngaphezu kwalokho, le ndlela ayisebenzi ezingxenyeni ezincane noma emimoyeni emincane eyinkimbinkimbi enama-undercuts kanye namarediya aqinile.
Enye indlela yokuhlola ukonakala okungaphezulu njengokuqhekeka nama-voids usebenzisa leyo ebizwa ngokuthi ?Met-L-Check?indlela yokudaya yokungena.Kodwa le ndlela ilinganiselwe ekutholeni amaphutha angaphezulu kuphela.
Isakhiwo Samakhemikhali
I-PFA, eguquguqukayo, ingahlolwa ngokuthembekile.Imifantu nama-voids ngaphansi kobuso kungenziwa kubonakale ngemithombo yokukhanya efanelekile.Izindawo okungafinyeleleki kalula kuzo olayini zingahlolwa kusetshenziswa izibani ezikhanyayo ezibandayo neziqondiso zokukhanya zefiber eziguquguqukayo.
Izindleko Ukuqhathanisa for Linings
Ngokwezintengo zezinto ezingavuthiwe, i-PFA ibiza cishe ngokuphindwe kathathu kune-PTFE.
Lokhu kungalungile, nokho, kunganxeshezelwa noma kuncishiswe kakhulu, njengomsebenzi wezinto ezinjengomumo okufanele ulayini, ubukhulu bawo, inani lezinto zokusebenza okufanele zifakwe ulayini kanye nendlela yokucubungula eyamukelwa.Lokhu kungenzeka ngoba i-PFA ayidingi ukulungiswa kwenqubo eyenziwa ngesandla noma ukuqeda imishini ngokulahleka kwempahla okuhambisanayo.
Ukusetshenziswa kwe-PFA kokuhlanganisa izingxenye ezinkulu kakhulu akunconywa, ngoba izindleko zempahla ephezulu zingenza ingxenye ibize kakhulu.Elinye iphuzu okufanele ligcinwe engqondweni yizindleko zamathuluzi, angakhokhiswa imali
lapho izinombolo ezincane kuphela okufanele zifakwe kulayini.Ngaphezu kwalokho, kunemikhawulo esebenzayo yesisindo sezinto ezijovwe imishini yokubumba ekwazi ukuyiphatha.
Iziphetho
Ngaphezulu kweminyaka engu-20 yokuhlangenwe nakho kwama-lining ezingxenyeni ezihlukahlukene, isib. ama-valve nezindlu zephampu, abonise ukuthi i-PFA inezinzuzo eziningi lapho ukumelana nokushisa okuphezulu namakhemikhali kuyizidingo eziyinhloko.
Ukuqina kodonga okunembile okungafinyelelwa nge-PFA kuyinzuzo enkulu, ikakhulukazi uma usebenza nabezindaba abanomkhuba oqinile wokusabalalisa.
Okuhlangenwe nakho okungokoqobo kuphinde kwabonisa ukuthi i-PFA inikeza izakhiwo ezingcono zokuvimbela kune-PTFE.
Abakhiqizi be-Bromine babika, isibonelo, ukuthi ukujula kokungena kwe-bromine ku-PFA kungaphansi kwengxenye eyodwa kwezintathu kune-PTFE, lapho izimo zokusebenza ezifana nesikhathi, izinga lokushisa nokucindezela kufana.
I-PTFE, ngakolunye uhlangothi, isasetshenziswa kabanzi ezingxenyeni zamavalvu ekhemikhali nezinye izisetshenziswa zokucubungula amakhemikhali lapho kudingeka ukumelana nokukhathala.
Izibonelo ezijwayelekile zezicelo ezinjalo ziyizimbongolo, kanye nama-diaphragms kuma-valve namaphampu.
Ngamasongo ezihlalo, amapulaki, izigxivizo nezingxenye ezifanayo, i-PTFE iyinto efanelekile neyongayo.
Ukuthambekela kwakamuva kwezingxenye ezifana nalezi ukusebenzisa i-PTFE eguquliwe, njengoba ukuzinza nokuqina kwayo kwe-dimensional kuphakeme kunaleyo ye-PTFE ejwayelekile.
Amathegi:PTFE,PFA,PTFE vs PFA
Isikhathi sokuthumela: Apr-01-2017