Yisiphi Isici Esingcono Kakhulu Sophawu Lomshini Olumelana Nokugqwala?

Isingeniso

Ukukhetha izinto zokwakha uphawu lomshini olumelana nokugqwala akukhona ukuthola inketho eyodwa "engcono kakhulu" emhlabeni wonke, kodwa mayelana nokufanisa ubuso bophawu, ama-elastomer, nezingxenye zensimbi noketshezi, izinga lokushisa, ingcindezi, kanye nezimo zokusebenza. Inhlanganisela engalungile ingasheshisa ukuguguleka, ibangele ukuhlaselwa ngamakhemikhali, futhi ifinyeze impilo yophawu, okuholela ekuvuza, isikhathi sokungasebenzi, kanye nezingozi zokuphepha. Lesi sihloko sichaza ukuthi izinketho zezinto ezivamile ezifana ne-silicon carbide, i-tungsten carbide, i-Hastelloy, i-PTFE, kanye nama-elastomer akhethekile asebenza kanjani enkonzweni yokugqwala, nokuthi ungazihlola kanjani ngokusekelwe kumakhemikhali enqubo ukuze ukwazi ukuthola ukwakhiwa kophawu okufanele kakhulu kwesicelo sakho.

Kungani Ukukhetha Izinto Ezibalulekile Kubalulekile Ezimpawini Zemishini Ezimelana Nokugqwala

Ukucacisa i-uphawu lomshini olumelana nokugqwalaingenye yezinqumo zobunjiniyela ezibaluleke kakhulu ezinhlelweni zokuphatha uketshezi.Izimpawu zomshini zisebenza njengesithiyo esiyinhlokophakathi koketshezi lwenqubo olunamandla kanye nendawo engaphandle, ukuvimbela ukukhishwa okuyingozi kanye nokuvikela izingxenye zephampu zangaphakathi. Lapho kucutshungulwa imithombo egqwalisayo kakhulu—njenge-asidi enamandla, ama-alkali e-caustic, noma izinyibilikisi ezinamandla—umkhawulo wephutha awukho nhlobo. Ukuwohloka kwezinto kungenzeka ngokushesha, okuholela ekulahlekelweni kokugcinwa, izingozi zemvelo, kanye nomonakalo omkhulu wemishini.

Inqubo yokukhetha idinga ukuqonda okuphelele kwe-metallurgy, i-tribology, kanye ne-elastomer chemistry. I-mechanical seal akuyona ingxenye ye-monolithic; iyinhlanganisela yobuso obujikelezayo nobunganyakazi, izinto zokuvala zesibili, kanye ne-hardware yensimbi. Ingxenye ngayinye yalezi zingxenye kumele imelane ngokuzimela nendawo yamakhemikhali ngenkathi igcina ukubekezelelana okunembile kwemishini ngaphansi kwezingcindezi namazinga okushisa ahlukahlukene. Ukwehluleka ukuhlanganisa izinto ezifanele ne-fluid chemistry ethile kunciphisa kakhulu i-Mean Time Between Failures (MTBF) futhi kwandisa izingozi zokusebenza.

I-chemistry yenqubo, ingozi yokuvuza, kanye nomthelela wesikhathi sokungasebenzi

I-chemistry yenqubo inquma izinga kanye nendlela yokuwohloka kwezinto. Uketshezi lwezimboni lungabonisa amazinga e-pH aphakeme kakhulu, kusukela ku-acidic ephezulu (pH < 1) kuya ku-alkaline ephezulu (pH > 13), ngayinye ihlasela izinto ngendlela ehlukile. Isibonelo, ama-oxidizing acid njenge-nitric acid angadlulisa izinsimbi ezithile ezingagqwali kodwa abhubhise ngokushesha ubuso be-carbon seal ejwayelekile. Ngaphezu kwalokho, ukungcola okumbalwa, okuvame ukunganakwa ekuchazweni koketshezi oluningi, kungasebenza njengezinto ezibangela ukugqwala kwendawo njengokugqwala kwemigodi noma i-crevice.

Ingozi yokuvuza ehlotshaniswa nokukhethwa kwezinto okungalungile idlulela ngale kokwehluleka okulula komshini. Ekucutshungulweni kwamakhemikhali kanye nokuhluzwa kwe-petrochemical, ama-volatile organic compounds (ama-VOC) kanye nokungcola komoya okuyingozi kumele kulawulwe ngokuqinile. Imithethonqubo ye-Environmental Protection Agency (EPA) ivame ukuphoqelela ukuthi ukukhishwa kwe-pump seal kuhlale ngaphansi komkhawulo wezingxenye ezingu-500 ngesigidi (ppm). Ukwephulwa okubangelwa ukugqwala ebusweni be-seal noma ukuwohloka kwe-elastomer kungabangela ukwephulwa kwemithetho ngokushesha, kudinge ukuvalwa okuphuthumayo futhi kubangele ukubika okuphoqelekile kwemvelo.

Izindleko zokwehluleka zihlotshaniswa nokuhambisana okungekuhle kwezinto ezibonakalayo

Imiphumela yezezimali yokuhambisana kabi kwezinto ezibonakalayo idlula kakhulu izindleko zokuqala zokuthenga uphawu lomshini ngokwalo. Lapho uphawu luphela ngaphambi kwesikhathi ngenxa yokuhlaselwa ngamakhemikhali, izindleko zokufaka esikhundleni ngqo ziyanda ngenxa yomsebenzi odingekayo wokukhipha ipompo, ukuhlanza, nokufaka kabusha. Okubaluleke kakhulu, izindleko ezingaqondile ezihlobene nesikhathi sokungasebenzi esingahleliwe zingaba zimbi kakhulu. Ezindaweni zokucubungula eziqhubekayo ezisebenzisa amandla amaningi, ukwehluleka kwepompo okungalindelekile kungamisa umugqa wokukhiqiza, kubangele izindleko zesikhathi sokungasebenzi ezisukela ku-$10,000 kuya ngaphezulu kuka-$50,000 ngehora kuye ngemboni kanye nenani lomkhiqizo.

Ngaphezu kwalokho, ukuvuza okugqwalisayo kungabangela umonakalo obalulekile emishinini ezungezile. I-seal ethintekile ivumela amakhemikhali anamandla ukuthi ahlasele i-pump shaft, ama-bearings, kanye ne-motor housings. Lokho okuqala njengokwehluleka kwe-seal okusendaweni kungakhula ngokushesha kube ukwehluleka kwe-pump okubangela inhlekelele okudinga ukwakhiwa kabusha okuphelele kohlaka lwe-bearing noma ukushintshwa kwe-shaft. Ukutshala imali ezintweni ezifanele ezingamelani nokugqwala kusengaphambili—noma ngabe kwandisa izindleko zezingxenye zokuqala ngo-200% kuya ku-300%—kuholela ekubuyiselweni kwe-Investment (ROI) okuphezulu kakhulu ngokwandisa i-MTBF kusukela ezinyangeni ezimbalwa kuya eminyakeni eminingana.

Izinketho Zezinto Zokusebenza Zezivalo Zemishini Ezimelana Nokugqwala

Ukwakha uphawu lomshini olungagqwali kudinga ukukhetha izinto ezikhethekile zezindawo ezintathu ezihlukene: ubuso bophawu oluyinhloko, ihadiwe yensimbi (izipilingi, izikhonkwane zokushayela, kanye nama-gland), kanye nezinto zokuvala zesibili (ama-O-rings nama-gaskets). Indawo ngayinye ibhekene nokucindezeleka kokusebenza okuhlukile, okusho ukuthi into esebenza kahle kakhulu njengendandatho ye-O engaguquki ingase ingafaneleki nhlobo ebusweni bophawu oluguquguqukayo, olukhiqiza ukushisa.

Izinto zokuvala ubuso njenge-silicon carbide

Ubuso besiciko esiyinhloko yizona zinto ezibaluleke kakhulu, njengoba zigcina ifilimu yoketshezi oluncane ngenkathi zijikelezana.I-silicon carbide (i-SiC)ibhekwa kabanzi njengento eyinhloko yobuso be-seal yesevisi yamakhemikhali enzima. Ngokukhethekile, i-silicon carbide eqondile (i-alpha) inikeza ukumelana kwamakhemikhali okuseduze nendawo yonke kububanzi be-pH obungu-0 kuya ku-14 futhi ingamelana namazinga okushisa okusebenza afinyelela ku-300°C (572°F). Ngokungafani ne-silicon carbide eboshwe yi-reaction-bonded, equkethe i-silicon yamahhala engakhishwa yi-caustics enamandla noma i-hydrofluoric acid, i-SiC e-alpha-sintered ihlala izinzile ngokwesakhiwo cishe kuzo zonke izinhlobo ze-aggressive media.

Ezinye izinketho zezinto zobuso zifaka i-tungsten carbide (WC) kanye namazinga ahlukahlukene e-carbon. I-tungsten carbide ihlala isikhathi eside futhi ayithinteki, okwenza ifanelekele ukugqwala, kodwa ukumelana kwayo namakhemikhali kuncike kakhulu ku-binder yayo. I-tungsten carbide eboshwe nge-nickel ngokuvamile ikhethwa kunezinhlobo eziboshwe nge-cobalt ezindaweni ezigqwalisayo, yize isalokhu ingaphansi kwe-SiC kuma-asidi aqinile. Ubuso be-carbon obufakwe nge-antimony noma obufakwe nge-resin buvame ukusetshenziswa njengendandatho yokuhlangana ngokumelene ne-SiC ngenxa yezakhiwo zabo ezinhle kakhulu zokuzigcoba, uma nje uketshezi lwenqubo lungenazo izinto ezinamandla zokuxilisa ezihlasela isakhiwo se-carbon.

Izinsimbi nama-alloy amelana nokugqwala

Izingxenye zensimbi zesivalo, okuhlanganisa ipuleti le-gland, isilikhi, kanye neziphethu, kumele zimelane nokugqwala okufanayo kanye nokuhlaselwa kwendawo efana nokuqhekeka kwemigodi kanye nokuqhekeka kwe-stress corrosion (SCC). Ngenkathi insimbi engagqwali engu-316 iyindinganiso yemboni yesevisi ejwayelekile, isengozini enkulu yokuhlaselwa yimigodi ebangelwa yi-chloride. Ezindaweni ezinolaka, onjiniyela kumele bacacise ama-alloy ebanga eliphakeme ngokusekelwe ku-Pitting Resistance Equivalent Number (PREN) yabo. I-PREN engaphezu kuka-40 ivame ukudingwa ukuze kusetshenziswe i-chloride noma i-acidic enzima.

I-Hastelloy C-276 (PREN > 45) ingenye yama-alloy e-nickel-molybdenum-chromium aguquguqukayo kakhulu, enikeza ukumelana okumangalisayo negesi ye-chlorine emanzi, ama-hypochlorite, kanye nohlu olubanzi lwama-acid e-organic kanye nama-inorganic. I-Titanium Grade 2 ivame ukukhethwa ukuze isetshenziswe njenge-oxidizing media kanye nezicelo zamanzi olwandle ngenxa yefilimu yayo ye-oxide ezinzile, evikelayo, yize isengozini ye-chlorine eyomile. I-Alloy 20 ingenye indlela evamile, eyenzelwe ngqo ukumelana nokuhlaselwa yi-sulfuric acid emazingeni okushisa aphezulu kanye nokugxila.

Ama-Elastomer nezinto zokuvala zesibili

Izinto zokuvala zesibili, ngokuvamile ama-O-rings, zinikeza uphawu oluqinile phakathi kwe-mechanical seal assembly kanye ne-pump casing. Ukukhethwa kwe-elastomer kuvame ukuba yisici esivimbelayo ekusebenzeni kwamakhemikhali nokushisa kwe-seal. Ama-Fluoroelastomers (FKM), aziwa kakhulu ngegama lomkhiqizo i-Viton, ajwayelekile kuma-acid amaningi athambile kanye noketshezi olusekelwe kuphethiloli kodwa ancipha ngokushesha kuma-ketones, ama-amine, kanye nama-alkali aqinile.

Ukuze kube nokumelana okukhulu nokugqwala, kudingeka ama-perfluoroelastomers (FFKM), njengeKalrez noma iChemraz,. Ama-compound e-FFKM anikeza ukumelana kwamakhemikhali okufana kakhulu ne-PTFE kodwa agcina inkumbulo yokunwebeka edingekayo yokuvala ngokuguquguqukayo. Angamelana nezinyibilikisi ezinamandla, ama-acid aqinile, kanye nezisekelo emazingeni okushisa asebenzayo aqhubekayo afinyelela ku-327°C (620°F). Lapho imikhawulo yesabelomali ivimbela ukusetshenziswa kwe-FFKM ephelele, ama-FKM afakwe ku-PTFE noma ama-O-ring e-silicone ahlinzeka ngenye indlela engabizi kakhulu, enikeza ukungangeni kwamakhemikhali kwejazi le-PTFE ngokuqina komshini kwe-elastomer core.

Indlela Yokuhlola Izinto Zokuvala Izimo Zesevisi

Ukuhlola izinto zokuvala kudinga ukudlulela ngale kwamashadi ayisisekelo okuhambisana namakhemikhali nokuhlaziya izimo eziguquguqukayo zendawo yokusebenza. Izinto ezingasebenzisi amakhemikhali kahle ekamelweni zingase ziwohloke ngokushesha uma zibhekene nokushisa okubangelwa ukungqubuzana okukhiqizwa ebusweni bokuvala noma lapho amazinga oketshezi eshintshashintsha ngesikhathi sokuphazamiseka kwenqubo. Onjiniyela kumele bahlole yonke imvilophu ye-thermodynamic kanye neyamakhemikhali yesicelo.

Izinguquko zokusebenza ezifana nokuhlushwa, ama-chloride, kanye nokushisa

Izinga lokushisa, ukuhlushwa, kanye nokuba khona kwama-ion athile kushintsha kakhulu amazinga okugqwala. Isibonelo, insimbi engagqwali engu-316 iyamukeleka ngokuphelele emanzini okushisa azungezile, kodwa uma ukuhlushwa kwe-chloride kudlula i-1000 ppm futhi amazinga okushisa enyuka ngaphezu kuka-60°C (140°F), izinto ezisetshenziswayo ziba sengozini enkulu yokuqhekeka kokugqwala kokucindezeleka (SCC) kanye nokuqhekeka okusheshayo. Ngenxa yalokho, ukusetshenziswa okubandakanya amanzi ashisayo noma amanzi olwandle kuvame ukudinga izinsimbi ezingagqwali ezimbili noma ngaphezulu noma i-titanium.

Ukuhlushwa kwe-asidi kubaluleke kakhulu. I-asidi ye-sulfuric ibonisa iphrofayili yokugqwala okungeyona eqondile: i-asidi ye-sulfuric encibilikisiwe ingcolisa kakhulu izinsimbi eziningi, idinga i-Hastelloy noma i-Alloy 20, kanti i-asidi ye-sulfuric encibilikisiwe (>90%) ngezinye izikhathi ingaphathwa yizinsimbi ze-carbon ezijwayelekile emazingeni okushisa aphansi ngenxa yokwakheka kwefilimu ye-sulfate edlulayo. Kodwa-ke, uma i-asidi encibilikisiwe imunca umswakama emoyeni, ukuhlushwa kwendawo kuzoqala ngokushesha ukuhlasela okukhulu kokugqwala kwihadiwe yesivalo.

Ukushintshana kwezinto ezibonakalayo kanye nezici zokuqhathanisa

Ukukhetha izinto ezifanele ngokuvamile kuhilela ukulinganisela izakhiwo ezincintisanayo zemishini namakhemikhali. Ngenkathi i-silicon carbide ene-alpha-sintered inikeza ukumelana nokugqwala okungenakuqhathaniswa, iyaphuka kakhulu. Uma ipompo ibhekana nokuqhekeka okukhulu noma ukuphambuka komgodi, ubuso be-SiC bungaphuka ngendlela eyingozi. Ezisetshenzisweni lapho ukushaqeka komshini kuyinkathazo eyinhloko kanye nokugqwala, onjiniyela bangase bayeke ukusebenzisa ubuso be-tungsten carbide obuqinile, nakuba bungenamakhemikhali amaningi.

Ukushisa okushisayo kungenye into ebalulekile yokuqhathanisa. Ubuso be-Seal bukhiqiza ukushisa okukhulu okungqubuzanayo, okumele kuhlakazwe kuketshezi lwenqubo ukuvimbela uketshezi ukuthi lukhanye lube umhwamuko. I-SiC inokushisa okuhle kakhulu okufudumezayo, idonsa ukushisa kude ne-seal interface ngokushesha kakhulu kune-alumina ceramic noma i-carbon. Leli khono linciphisa ingozi yokushaqeka kokushisa futhi landisa impilo yama-elastomer esibili.

Uma ukuthuthukiswa okukodwa kwezinto kunganele

Kwezinye izinhlelo zokusebenza ezibucayi, ukuthuthukisa insimbi kanye nezinto zobuso zesivalo esisodwa somshini akwanele ukuqinisekisa ukuthembeka. Uma uketshezi luyingozi kakhulu, lunobuthi, noma luthambekele ekubumbeni i-polymer lapho luthinta umoya-mpilo womoya, ukusetshenziswa kudingaukuhlelwa kwesivalo okubili komshiniIzivikelo ezimbili zisebenzisa amasethi amabili obuso besivikelo bese zethula isithiyo noma uketshezi lwe-buffer phakathi kwazo.

Ngaphansi kwezinhlelo zokufaka amapayipi ezijwayelekile ze-American Petroleum Institute (API), njenge-API Plan 53A noma 54, uketshezi oluvimbelwe lucindezelwa lusakazwa phakathi kwezivalo zangaphakathi kanye nezangaphandle. Lolu ketshezi lugcinwa lucindezelwa cishe ngo-10% kuya ku-15% (ngokuvamile luyi-1.5 kuya ku-2.0 bar) oluphakeme kunomfutho webhokisi lokufutha iphampu. Ngenxa yokuthi uketshezi oluvimbelwe lucindezelwa kakhulu, noma yikuphi ukuvuza ebusweni besivalo sangaphakathi kugeleza enkambisweni, okuqinisekisa ukuthi uketshezi lwenqubo oluqothulayo alukaze luthinte izingxenye zesivalo sangaphandle noma luphume luye emkhathini. Leli cebo livumela ihadiwe yesivalo sangaphandle ukuthi yakhiwe ngezinto ezijwayelekile, ezingabizi kakhulu.

Izici Zokuthengwa Nokuhambisana Nomthetho Ekukhetheni Izinto Ezibalulekile

Ukuthola izivalo zemishini ezingagqwali kuhilela ukuhamba ngezintambo zokuphakelwa eziyinkimbinkimbi, ukuphatha izikhathi ezengeziwe zokuhola zezinto ezingavamile, nokuqinisekisa ukunamathela ngokuqinile ezindinganisweni zokuthobela imithetho yemboni. Ukwehluleka ukubhala phansi nokuqinisekisa ukwakheka kwezinto kungaholela ekwehlulekeni okubi kakhulu kanye nezikweletu ezinkulu zomthetho, ikakhulukazi emikhakheni elawulwa kakhulu njengeuwoyela negesi, imithi, kanye nokucubungula amakhemikhali.

Izindinganiso, imibhalo, kanye nokulandeleka

Izicelo ezinobungozi obukhulu zidinga imibhalo eqinile ukuqinisekisa ukuthi izinto ezichaziwe zisetshenziswe ngempela ekwakhiweni kwesivalo. Embonini yamakhemikhali kaphethiloli, izivalo zemishini kumele zihambisane njalo nezindinganiso ze-API 682 4th Edition, ezinquma izigaba ezithile zezinto ezisetshenziswayo zezimo zesevisi ezahlukene. Ezisetshenzisweni ezibandakanya i-hydrogen sulfide (H2S), izingxenye zensimbi kumele zihambisane ne-NACE MR0175 / ISO 15156 ukuvimbela ukuqhekeka kokucindezeleka kwe-sulfide.

Ukuze kuqinisekiswe ukulandeleka, onjiniyela bokuthenga bavame ukudinga imibiko yokuhlolwa kwezinto (ama-MTR) yazo zonke izingxenye zensimbi ezimanzi. Ngaphezu kwalokho, izikhungo zingenza ukuhlolwa kwe-Positive Material Identification (PMI) lapho zithola uphawu. I-PMI isebenzisa abahlaziyi be-X-ray fluorescence (XRF) ukuqinisekisa ukwakheka kwezinto ezihlanganisiwe ngokungabhubhisi, ukuqinisekisa ukuthi umhlinzeki akazange afake ngengozi insimbi engagqwali engu-304 esikhundleni se-Hastelloy C-276 eceliwe.

Amandla omhlinzeki kanye nezingozi zokuthola ulwazi

Ukutholwa kwama-alloy angaphandle kanye nama-elastomer asebenza kahle kakhulu kunezingozi ezikhona.

Indlela Yokukhetha Inhlanganisela Yezinto Ezinhle Kakhulu

Izinto Ezibalulekile Okufanele Uzicabangele

• Iziphetho ezibaluleke kakhulu kanye nesizathu sokuvalwa komshini okumelana nokugqwala
• Imininingwane, ukuhambisana, kanye nokuhlolwa kwengozi okufanele kuqinisekiswe ngaphambi kokuthi uzibophezele
• Izinyathelo ezilandelayo ezisebenzayo kanye nezixwayiso abafundi abangazisebenzisa ngokushesha

imibuzo ejwayelekile ukubuzwa

Yisiphi isiciko sobuso besivalo esivame ukuba ngcono kakhulu kwisivalo somshini esimelana nokugqwala?

I-Alpha-sintered silicon carbide ivame ukuba yisinqumo esihle kunazo zonke ngoba iphatha ama-asidi amaningi, ama-alkali, kanye namazinga okushisa aphezulu kangcono kunezimo zekhabhoni ezijwayelekile.

Kufanele kugwenywe nini ubuso be-tungsten carbide noma be-carbon?

Gwema ikhabhoni ejwayelekile ezitsheni ezikhipha i-oxidizing enamandla noma ezibola kakhulu. Qaphela nge-tungsten carbide lapho kungenzeka khona ukuhlaselwa ngamakhemikhali; qinisekisa ukuhambisana koketshezi ngaphambi kokukhetha.

Ingabe zonke izinhlangothi ze-silicon carbide seal zimelana nokugqwala ngokulinganayo?

Cha. I-SiC e-Alpha-sintered ngokuvamile inikeza ukumelana okungcono kwamakhemikhali kune-SiC eboshiwe, ikakhulukazi ezinkingeni ezinamandla kanye nezinye izinsizakalo zamakhemikhali ezinolaka.

Yiziphi ezinye izingxenye zesivalo okumelwe zimelane nokugqwala ngaphandle kobuso?

Hlola izingxenye zensimbi kanye nama-elastomer. Ama-spring, ama-gland, kanye nama-O-ring kumele afane noketshezi lwenqubo, izinga lokushisa, kanye nengcindezi kungenjalo uphawu lungahluleka ngisho noma ubuso obuphezulu busebenza kahle.

Ingabe i-Victor Seals ingasiza ekuqhathaniseni izivalo ezingamelana nokugqwala namamodeli ephampu e-OEM?

Yebo. I-Victor Seals inikeza izivalo zemishini ezihambisana ne-OEM nezishintshayo zezinhlobo eziningi zamaphampu ezimboni, okusiza amaqembu okulungisa ukukhetha izinto ezifanele zemisebenzi yokugqwala.