Wannan jagorar da aka kwatanta yana nuna wasu matsalolin gama gari waɗanda zasu iya faruwa tare da polymer da kayan elastomeric waɗanda suka bambanta da waɗanda ke faruwa tare da hatimin ƙarfe da abubuwan haɗin gwiwa.
Rashin gazawar kayan aikin polymer (filastik da elastomeric) da sakamakonsa na iya zama mai tsanani kamar gazawar kayan ƙarfe.Bayanin da aka gabatar yana bayyana wasu kaddarorin da ke shafar kayan aikin polymer da ake amfani da su a wuraren masana'antu.Wannan bayanin ya shafi wasu abubuwan gadoO-zobe, bututu mai layi, fiber ƙarfafa filastik (FRP) da bututu mai layi.Misalai na kaddarorin kamar shigar ciki, zafin gilashin, da viscoelasticity da tasirinsu an tattauna su.
Ranar 28 ga Janairu, 1986, bala'in jirgin sama na Challenger ya girgiza duniya.Fashewar ta faru ne saboda O-ring bai rufe yadda ya kamata ba.
Laifin da aka bayyana a cikin wannan labarin yana gabatar da wasu halaye na kurakuran da ba na ƙarfe ba da ke shafar kayan aikin da ake amfani da su a aikace-aikacen masana'antu.Ga kowane hali, ana tattauna mahimman kaddarorin polymer.
Elastomers suna da zafin canjin gilashin, wanda aka ayyana a matsayin "zazzabi a lokacin da wani abu mai amorphous, kamar gilashi ko polymer, ya canza daga yanayin gilashin gaggautsa zuwa yanayin ductile" [1].
Elastomers suna da saitin matsawa - "an bayyana shi azaman adadin nau'in da mai elastomer ba zai iya murmurewa ba bayan ƙayyadadden lokaci a wani extrusion da zazzabi" [2].A cewar marubucin, matsawa yana nufin ikon roba don komawa zuwa ainihin siffarsa.A yawancin lokuta, ana samun riba ta matsawa ta wasu haɓakawa waɗanda ke faruwa yayin amfani.Koyaya, kamar yadda misalin da ke ƙasa ya nuna, ba koyaushe haka lamarin yake ba.
Laifi 1: Ƙananan zafin jiki (36°F) kafin ƙaddamarwa ya haifar da rashin isassun Viton O-rings akan Challenger na Jirgin Sama.Kamar yadda aka bayyana a cikin binciken hatsarori daban-daban: "A yanayin zafi da ke ƙasa da 50 ° F, Viton V747-75 O-ring ba shi da sauƙi don gano buɗewar tazarar gwaji" [3].Matsakaicin canjin gilashin yana haifar da ƙalubalen O-ring ya kasa yin hatimi da kyau.
Matsala ta 2: Hatimin da aka nuna a Figures 1 da 2 an fara fallasa su da ruwa da tururi.An haɗa hatimin akan wurin ta amfani da ethylene propylene diene monomer (EPDM).Duk da haka, suna gwada fluoroelastomer (FKM) irin su Viton) da perfluoroelastomer (FFKM) irin su Kalrez O-rings.Ko da yake masu girma dabam sun bambanta, duk O-zoben da aka nuna a hoto na 2 suna fara girma iri ɗaya:
Me ya faru?Yin amfani da tururi na iya zama matsala ga elastomer.Don aikace-aikacen tururi sama da 250°F, haɓakawa da nakasar ƙanƙancewa FKM da FFKM dole ne a yi la'akari da su cikin lissafin ƙira.Elastomers daban-daban suna da wasu fa'idodi da rashin amfani, har ma waɗanda ke da juriya na sinadarai.Duk wani canje-canje yana buƙatar kulawa a hankali.
Gabaɗaya bayanin kula akan elastomers.Gabaɗaya, amfani da elastomers a yanayin zafi sama da 250°F da ƙasa da 35°F ya ƙware kuma yana iya buƙatar shigarwar mai ƙira.
Yana da mahimmanci don ƙayyade abin da aka yi amfani da shi na elastomeric.Fourier canza infrared spectroscopy (FTIR) zai iya bambanta tsakanin nau'ikan elastomers daban-daban, kamar EPDM, FKM da FFKM da aka ambata a sama.Koyaya, gwaji don bambanta mahaɗan FKM ɗaya daga wani na iya zama ƙalubale.O-zoben da masana'antun daban-daban suka yi na iya samun filaye daban-daban, vulcanizations, da jiyya.Duk wannan yana da tasiri mai mahimmanci akan saitin matsawa, juriya na sinadarai da ƙananan yanayin zafi.
Polymers suna da tsayi, mai maimaita sarƙoƙi na ƙwayoyin cuta waɗanda ke ba da damar wasu ruwaye su ratsa su.Ba kamar karafa ba, waɗanda ke da tsari na crystalline, dogayen ƙwayoyin cuta suna yin cuɗanya da juna kamar madaidaicin dafaffen spaghetti.A zahiri, ƙananan ƙwayoyin cuta irin su ruwa / tururi da gas na iya shiga.Wasu kwayoyin suna da ƙanƙanta don dacewa da giɓin da ke tsakanin sarƙoƙi ɗaya.
Kasawa ta 3: Yawanci, tattara bayanan binciken binciken gazawa yana farawa da samun hotunan sassan.Duk da haka, lebur ɗin lebur, mai sassauƙa, mai ƙamshin man fetur da aka samu ranar Juma'a ya zama bututu mai wuya a ranar Litinin (lokacin da aka ɗauki hoton).An ba da rahoton cewa, abin da ke cikin jakar bututun polyethylene (PE) ne da ake amfani da shi don kare kayan lantarki da ke ƙasa da matakin ƙasa a gidan mai.Lebur ɗin filasta mai sassauƙa da ka karɓa bai kare kebul ɗin ba.Shigar da man fetur ya haifar da jiki, ba canje-canjen sinadarai ba - bututun polyethylene bai rushe ba.Duk da haka, wajibi ne a shiga ƙananan bututu masu laushi.
Laifi 4. Yawancin wuraren masana'antu suna amfani da bututun ƙarfe na Teflon don maganin ruwa, maganin acid da kuma inda aka cire kasancewar gurɓataccen ƙarfe (misali, a cikin masana'antar abinci).Bututun da aka lulluɓe Teflon suna da huluna waɗanda ke ba da damar ruwa ya shiga cikin sararin samaniya tsakanin karfe da rufin don matsewa.Koyaya, bututun da aka lika suna da rai mai rai bayan amfani mai tsawo.
Hoto na 4 yana nuna bututu mai layi na Teflon wanda aka yi amfani da shi don samar da HCl sama da shekaru goma.Yawancin samfuran lalata na ƙarfe suna tarawa a cikin sararin samaniya tsakanin layin layi da bututun ƙarfe.Samfurin ya tura rufin ciki, yana haifar da lalacewa kamar yadda aka nuna a hoto na 5. Lalacewar karfe yana ci gaba har sai bututun ya fara zubewa.
Bugu da kari, creep yana faruwa a kan Teflon flange surface.Ana bayyana Creep azaman nakasawa (nakasarwa) ƙarƙashin kaya akai-akai.Kamar yadda yake tare da karafa, raƙuman polymers yana ƙaruwa tare da ƙara yawan zafin jiki.Koyaya, ba kamar karfe ba, raƙuman ruwa yana faruwa a yanayin zafi.Mafi mahimmanci, yayin da ɓangaren giciye na gefen flange ya ragu, ƙullun bututun ƙarfe suna daɗaɗawa har sai zoben zobe ya bayyana, wanda aka nuna a cikin hoto.Tsagewar madauwari tana ƙara fallasa bututun ƙarfe zuwa HCl.
Kasawa 5: Manyan layukan polyethylene (HDPE) ana amfani da su a masana'antar mai da iskar gas don gyara layukan allurar ruwa na karfe.Duk da haka, akwai ƙayyadaddun ƙa'idodi na ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun ƙayyadaddun layi.Figures 6 da 7 suna nuna layin da ya gaza.Lalacewa ga layin bawul guda ɗaya yana faruwa lokacin da matsa lamba annulus ya wuce matsi na aiki na ciki - layin ya kasa saboda shiga.Ga masu layin HDPE, hanya mafi kyau don hana wannan gazawar ita ce a guje wa ɓarna cikin sauri na bututu.
Ƙarfin sassan fiberglass yana raguwa tare da maimaita amfani.Yadudduka da yawa na iya lalatawa da fashe na tsawon lokaci.API 15 HR "Babban Matsi Fiberglass Linear Pipe" ya ƙunshi bayanin cewa canjin 20% a matsa lamba shine iyakar gwaji da gyarawa.Sashe na 13.1.2.8 na Kanadiya Standard CSA Z662, Man Fetur da Gas Pipeline Systems, ya ƙayyadad da cewa canjin matsa lamba dole ne a kiyaye ƙasa da kashi 20% na ƙimar matsi na mai kera bututu.In ba haka ba, za a iya rage matsa lamba na ƙira har zuwa 50%.Lokacin zayyana FRP da FRP tare da sutura, dole ne a yi la'akari da nauyin hawan keke.
Laifi 6: Ƙasa (karfe 6) na bututun fiberglass (FRP) da ake amfani da su don samar da ruwan gishiri an rufe shi da polyethylene mai girma.An gwada sashin da ya gaza, bangaren mai kyau bayan gazawa, da kashi na uku (wakiltan bangaren masana'anta) an gwada su.Musamman ma, an kwatanta ɓangaren ɓangaren ɓangaren da ba a yi nasara ba tare da ɓangaren giciye na bututu da aka riga aka tsara na girman girman (duba Figures 8 da 9).Yi la'akari da cewa ɓangaren giciye da ya gaza yana da fage mai fa'ida na intralaminar waɗanda ba sa cikin bututun da aka ƙirƙira.Delamination ya faru a cikin sababbin bututu da da suka gaza.Delamination na kowa a cikin fiberglass tare da babban abun ciki na gilashi;Babban abun ciki na gilashi yana ba da ƙarfi mafi girma.Bututun ya kasance ƙarƙashin matsanancin matsin lamba (fiye da 20%) kuma ya gaza saboda hawan keke.
Hoto 9. Anan akwai ƙarin sassan giciye guda biyu na ƙãre gilashin fiberglass a cikin bututun fiberglass mai ɗimbin yawa.
A lokacin shigarwa na kan layi, ƙananan sassan bututu suna haɗa - waɗannan haɗin suna da mahimmanci.Yawanci, guda biyu na bututu suna butted tare kuma rata tsakanin bututu yana cike da "putty."Sannan an nannade mahaɗin a cikin yadudduka da yawa na ƙarfin ƙarfin fiberglass mai faɗi da kuma sanya shi da guduro.Matsakaicin waje na haɗin gwiwa dole ne ya sami isasshen murfin ƙarfe.
Abubuwan da ba na ƙarfe ba irin su layi da fiberglass suna da viscoelastic.Kodayake wannan yanayin yana da wuyar bayyanawa, bayyanarsa na kowa: lalacewa yawanci yakan faru a lokacin shigarwa, amma zubar ba ya faruwa nan da nan."Viscoelasticity wani abu ne na kayan da ke nuna duka danko da kaddarorin roba lokacin da suka lalace.Kayayyakin viscous (kamar zuma) suna tsayayya da kwararar juzu'i kuma suna lalacewa ta layi akan lokaci lokacin da ake amfani da damuwa.Kayan roba (kamar karfe) za su lalace nan da nan, amma kuma da sauri su koma yanayinsu na asali bayan an cire damuwa.Abubuwan Viscoelastic suna da kaddarorin biyu don haka suna nuna nakasar lokaci-lokaci.Elasticity yawanci yana fitowa daga shimfiɗar shaidu tare da jirage na crystalline a cikin daskararrun da aka ba da umarnin, yayin da danko yana haifar da yaduwar kwayoyin halitta ko kwayoyin halitta a cikin wani abu mai amorphous "[4].
Abubuwan fiberglass da filastik suna buƙatar kulawa ta musamman yayin shigarwa da sarrafawa.In ba haka ba, za su iya fashe kuma lalacewa bazai bayyana ba har sai an dade bayan gwajin hydrostatic.
Yawancin kasala na rufin fiberglass suna faruwa saboda lalacewa yayin shigarwa [5].Gwajin hydrostatic ya zama dole amma baya gano ƙananan lalacewa da ka iya faruwa yayin amfani.
Hoto 10. An nuna anan akwai mu'amalar ciki (hagu) da na waje (dama) tsakanin sassan bututun fiberglass.
Lalacewar 7. Hoto na 10 yana nuna haɗin sassa biyu na bututun fiberlass.Hoto na 11 yana nuna ɓangaren giciye na haɗin.Fushin waje na bututu bai isa ya ƙarfafa shi ba kuma an rufe shi, kuma bututun ya karye yayin sufuri.Ana ba da shawarwari don ƙarfafa haɗin gwiwa a cikin DIN 16966, CSA Z662 da ASME NM.2.
Manyan bututun polyethylene masu nauyi ba su da nauyi, masu jure lalata, kuma ana amfani da su sosai don bututun iskar gas da na ruwa, gami da hoses na wuta a wuraren masana'anta.Yawancin gazawar akan waɗannan layin suna da alaƙa da lalacewa da aka samu yayin aikin tono [6].Duk da haka, raguwar haɓakar haɓakar haɓaka (SCG) kuma na iya faruwa a ɗan ƙaramin matsi da ƙarancin damuwa.A cewar rahotanni, "SCG shine yanayin gazawar gama gari a cikin bututun polyethylene na ƙasa (PE) tare da rayuwar ƙira na shekaru 50" [7].
Laifi 8: SCG ya samo asali a cikin bututun wuta bayan fiye da shekaru 20 na amfani.Karayarsa yana da halaye kamar haka:
Rashin gazawar SCG yana da alamar karaya: yana da ƙarancin nakasu kuma yana faruwa saboda zobba masu yawa.Da zarar yankin SCG ya ƙaru zuwa kusan inci 2 x 1.5, faɗuwar ta yaɗu da sauri kuma fasalulluka na macroscopic sun zama ƙasa da bayyane (Figures 12-14).Layin na iya fuskantar canjin lodi fiye da 10% kowane mako.An ba da rahoton tsoffin haɗin gwiwa na HDPE sun fi juriya ga gazawa saboda hauhawar nauyi fiye da tsoffin haɗin gwiwar HDPE [8].Koyaya, wuraren da ake dasu yakamata suyi la'akari da haɓaka SCG azaman shekarun hoses na HDPE.
Hoto 12. Wannan hoton yana nuna inda T-reshen ke haɗuwa tare da babban bututu, yana haifar da tsagewar da kibiya ta nuna.
Shinkafa14. Anan zaka iya ganin kusa da saman karaya na reshe na T zuwa babban bututun T.Akwai tsage-tsafe na fili a saman ciki.
Matsakaicin Manyan Kwantena (IBCs) sun dace don adanawa da jigilar ƙananan sinadarai (Hoto 15).Suna da aminci sosai cewa yana da sauƙin manta cewa gazawarsu na iya haifar da babban haɗari.Duk da haka, gazawar MDS na iya haifar da asarar kuɗi mai yawa, wasu daga cikinsu marubutan sun bincika.Yawancin gazawar ana haifar da su ta hanyar rashin dacewa [9-11].Ko da yake IBC ya bayyana mai sauƙi don dubawa, fasa a cikin HDPE da ke haifar da rashin kulawa yana da wuyar ganewa.Ga manajojin kadara a cikin kamfanoni waɗanda akai-akai ɗaukar manyan kwantena masu ɗauke da kayayyaki masu haɗari, dubawa na yau da kullun da na waje da na ciki ya zama tilas.a Amurka.
Lalacewar Ultraviolet (UV) da tsufa sun yi yawa a cikin polymers.Wannan yana nufin dole ne mu bi umarnin ajiya na O-ring a hankali kuma muyi la'akari da tasirin rayuwar abubuwan waje kamar buɗaɗɗen tankuna da rufin kandami.Duk da yake muna buƙatar haɓaka (ƙasa) kasafin kuɗi na kulawa, wasu dubawa na abubuwan waje sun zama dole, musamman waɗanda aka fallasa ga hasken rana (Hoto 16).
Halaye irin su zafin canjin gilashin, saitin matsawa, shigar ciki, zafin dakin da ke rarrafe, danko, jinkirin yaduwa, da sauransu. ƙayyade halayen aikin filastik da sassa na elastomeric.Don tabbatar da inganci da ingantaccen kiyaye mahimman abubuwan haɗin gwiwa, dole ne a yi la'akari da waɗannan kaddarorin, kuma dole ne polymers su san waɗannan kaddarorin.
Marubutan suna son gode wa abokan ciniki masu basira da abokan aiki don raba abubuwan da suka gano tare da masana'antar.
1. Lewis Sr., Richard J., Hawley's Concise Dictionary of Chemistry, bugu na 12, Thomas Press International, London, UK, 1992.
2. Tushen Intanet: https://promo.parker.com/promotionsite/oring-ehandbook/us/en/ehome/laboratory-compression-set.
3. Lach, Cynthia L., Tasirin Zazzabi da O-Ring Surface Jiyya akan Ƙarfin Ƙarfafawa na Viton V747-75.NASA Technical Paper 3391, 1993, https://ntrs.nasa.gov/archive/nasa/casi.ntrs.nasa.gov/19940013602.pdf.
5. Mafi kyawun Ayyuka don Masu Samar da Mai da Gas na Kanada (CAPP), "Amfani da Ƙarfafa Ƙarfafawa (Ba Karfe) Bututun," Afrilu 2017.
6. Maupin J. da Mamun M. Rashin gazawa, Hatsari da Binciken Hatsari na bututun filastik, Aikin DOT No. 194, 2009.
7. Xiangpeng Luo, Jianfeng Shi da Jingyan Zheng, Hanyoyin Slow Crack Growth a Polyethylene: Ƙayyadaddun hanyoyin Element, 2015 ASME Matsin Ruwa da Taron Bututu, Boston, MA, 2015.
8. Oliphant, K., Conrad, M., da Bryce, W., Gajiya na Ruwan Ruwa: Bita na Fasaha da Shawarwari don Tsarin Gaji na PE4710 Pipe, Rahoton Fasaha a madadin Ƙungiyar Bututun Filastik, Mayu 2012.
9. Sharuɗɗan CBA/SIA don Ajiye Liquids a cikin Matsakaicin Manyan Kwantena, ICB fitowa ta 2, Oktoba 2018 Kan layi: www.chemical.org.uk/wp-content/uploads/2018/11/ibc-guidance-issue-2- 2018-1.pdf.
10. Beale, Christopher J., Way, Yarjejeniya, Abubuwan da ke haifar da Leaks na IBC a cikin Shuke-shuken Sinadarai - Nazarin Ƙwarewar Aiki, Jerin Taro Na 154, ICEmE, Rugby, UK, 2008, kan layi: https://www.icheme.org/media/9737/xx-paper-42.pdf.
11. Madden, D., Kula da Totes na IBC: Nasihu Biyar don Sanya Su Ƙarshe, an buga su a cikin Kwantena masu yawa, IBC Totes, Dorewa, da aka buga akan blog.containerexchanger.com, Satumba 15, 2018.
Ana Benz ita ce Babban Injiniya a IRISNDT (5311 86th Street, Edmonton, Alberta, Canada T6E 5T8; Waya: 780-577-4481; Email: [email protected]).Ta yi aiki a matsayin lalata, gazawa da ƙwararriyar dubawa don shekaru 24.Kwarewarta ta haɗa da gudanar da bincike ta hanyar amfani da ingantattun dabarun dubawa da tsara shirye-shiryen binciken shuka.Mercedes-Benz tana hidimar masana'antar sarrafa sinadarai, masana'antar petrochemical, masana'antar taki da nickel a duk duniya, da kuma masana'antar samar da mai da iskar gas.Ta sami digiri a fannin injiniyan kayan aiki daga Universidad Simon Bolivar a Venezuela da kuma digiri na biyu a fannin injiniyan kayan aiki daga Jami'ar British Columbia.Ta na riƙe da yawa Kanad General Standards Board (CGSB) takaddun shaida mara lalacewa, da kuma API 510 takaddun shaida da takardar shedar CWB Group Level 3.Benz ya kasance memba na reshen zartarwa na NACE Edmonton na tsawon shekaru 15 kuma a baya ya yi aiki a mukamai daban-daban tare da Reshen Edmonton Canadian Welding Society.
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