Izivalo zakho ze-valve ziyahluleka ekushiseni kwasezindaweni ezishisayo naselangeni. Lokhu kuholela ekuvuzeni okubizayo, ukungasebenzi kwesistimu, kanye namakhasimende angajabuli abuza ikhwalithi yomkhiqizo wakho kanye nedumela lakho.

Ezimweni zezulu ezishisayo, i-EPDM ingcono kakhulu kunoma yikuphi ukusetshenziswa kwamanzi okuvezwe elangeni kanye nesimo sezulu ngenxa yokumelana kwayo okuhle kakhulu kwe-UV ne-ozone. Sebenzisa i-NBR kuphela ekusetshenzisweni kwangaphakathi okubandakanya uwoyela, lapho ivikelwe khona elangeni.

Bengixoxa nomlingani wami uBudi wase-Indonesia ngenkinga eqhubekayo omunye wamakhasimende akhe abhekene nayo. Babephethe ipulazi elikhulu lezolimo zasemanzini lapho amakhulu amavalvu ethu ayefakwe khona ngaphandle. Ngemva kwezinyanga eziyisithupha nje, amaningi aqala ukuvuza. Amavalvu ayelungile, kodwa izivalo ze-NBR ezijwayelekile ngaphakathi zaziqhekeka futhi ziqhekeka. Lena inkinga evamile ezimweni ezishisayo. Ukuhlanganiswa kwelanga elinamandla, ukushisa okuphezulu, kanye nomswakama kwakubhubhisa irabha. Sabasiza bashintshele kumavalvu nge-Izimpawu ze-EPDM, futhi inkinga yanyamalala. Lokhu okuhlangenwe nakho kubonisa kahle ukuthi kungani ukukhetha izinto ezibonakalayo kubaluleke kangaka ezindaweni ezishisayo.

Yikuphi okungcono kakhulu ezindaweni ezishisayo, i-NBR noma i-EPDM?

Izivalo ze-NBR zishibhile, okuyinto ebukeka kahle kakhulu uma ubhala ngesilinganiso. Kodwa ingabe lokhu kuzosindisa impilo uma izivalo ziwohloka ngokushesha ngaphansi kwelanga nokushisa okukhulu kwasezindaweni ezishisayo?

Ezinhlelweni zamanzi asezindaweni ezishisayo, i-EPDM ingcono kakhulu. Isakhiwo sayo samakhemikhali sakhiwe ukuze simelane ne-UV, i-ozone, nokushisa. Ukumelana nesimo sezulu esibi kwe-NBR kwenza kube ukukhetha okuyingozi kakhulu kunoma yikuphi ukusetshenziswa kwangaphandle endaweni eshisayo.

Lokhu akuyona indaba yombono; kuyindaba yekhemistri. I-EPDM inalokho okubizwa ngokuthi i-umgogodla we-polymer ogcwele. Lesi sakhiwo esizinzile simelana ngokwemvelo nokuhlaselwa yimisebe ye-UV kanye ne-ozone, izinto ezimbili ezitholakala kakhulu esimweni sezulu esishisayo esinelanga. Ngakolunye uhlangothi, i-NBR inomgogodla ongagcwele onezibopho ezimbili. Lezi zibopho ezimbili zingamaphuzu abuthakathaka aphuka kalula yimisebe ye-UV, okwenza izinto zibe buthakathaka futhi ziqhekeke. Endaweni efana ne-Indonesia noma iVietnam, uhlelo lokunisela lwangaphandle noma lokwelapha amanzi lubhekene nokuchayeka elangeni okungapheli. I-NBR seal ingase yehluleke ngaphansi konyaka. I-EPDM seal endaweni efanayo ingahlala iminyaka eminingi. Izindleko zokuqala eziphakeme kancane ze-EPDM yintengo encane okufanele ikhokhwe ukuze kuqinisekiswe ukuthembeka kwesikhathi eside nokugwema ukwehluleka kohlelo. Ukuhlaziywa kwezindleko nezinzuzo kusiza kakhulu i-EPDM kunoma yikuphi ukusetshenziswa kwangaphandle.

Yiziphi izinkinga zerabha ye-EPDM?

I-EPDM ibonakala ifanelekela imigqa yamanzi yangaphandle. Kodwa kwenzekani uma uketshezi luqukethe amafutha noma amakhemikhali asekelwe kuma-hydrocarbon? Ukusetshenziswa okungalungile kungabangela ukuthi uphawu lungasebenzi ngokuphelele.

Inkinga enkulu ye-EPDM ukumelana kwayo noketshezi olusekelwe kuphethiloli olufana namafutha, amafutha, kanye nezinyibilikisi eziningi. Ukuthintana nalezi zinto kuzokwenza ukuthi uphawu lwe-EPDM luvuvuke, luthambe, futhi lulahlekelwe amandla alo okuvala.

Umthetho kumakhemikhali uthi “njengokuncibilika okufana.” I-EPDM iyinto engekho e-polar, kanjalo namafutha e-hydrocarbon. Uma ihlangana, i-EPDM imunca uwoyela, okubangela ukuthi ivuvuke njengesiponji. Lokhu kuvuvukala kwenza izinto zibe buthaka kakhulu futhi kubhubhise ikhono layo lokubamba uphawu ngaphansi kwengcindezi. Lokhu kuyenza ingafaneleki nhlobo ekusetshenzisweni okubandakanya imigqa kaphethiloli, izinhlelo ze-hydraulic, noma izinqubo eziningi zamakhemikhali ezimboni. Okunye okubi izindleko. I-EPDM iyi-polymer ethuthukisiwe kakhulu, ngakho-ke izindleko zayo zokukhiqiza ziphakeme kune-NBR. Yingakho ivame ukubhekwa njengenketho ye-premium. Kodwa-ke, kubalulekile ukubuka lezi zindleko ngokomongo wohlelo lokusebenza. Ukuze uthole umsebenzi ofanele (amanzi, isimo sezulu, ukushisa), intengo yokuqala ephezulu ikuthengela iminyaka eminingi yesevisi engenazinkinga, okwenza izindleko zayo eziphelele zobunikazi zibe ziphansi kakhulu.

Yiziphi izinkinga ezinkulu ze-NBR?

I-NBR iyindinganiso engabizi kakhulu yezinhlelo zokusebenza eziningi. Kodwa ukumelana kwayo nesimo sezulu okungekuhle kungaholela ekuqhekekeni nasekuhlulekeni, okuyingozi enkulu kunoma iyiphi indawo engaphandle eshisayo.

Inkinga enkulu ye-NBR ukumelana kwayo nokukhanya kwelanga (i-UV), i-ozone, kanye nesimo sezulu esijwayelekile. Lokhu kubangela ukuthi iqine futhi iqhekeke. Iphinde ibe nesilinganiso sokushisa esiphansi kune-EPDM, okusheshisa ukuguga kwayo ezindaweni ezishisayo.

Emakethe efana neBudi's e-Indonesia, lesi yisici esibaluleke kakhulu okufanele usiqonde. Ukuhlanganiswa kokukhanya kwelanga okunamandla, unyaka wonke kanye nokushisa okuphezulu okuzungezile kuyindawo embi kakhulu ye-NBR. Imisebe ye-UV ihlasela ngqo amaketanga e-polymer, kuyilapho ukushisa kusheshisa le nqubo yokuguga. Lokhu kubangela ukuthi izinto zilahlekelwe ukuguquguquka kwazo, okuwumsebenzi wazo oyinhloko. Ukuvalwa okubuthakathaka akukwazi ukucindezela ukuvimba ukuvuza; kumane kuqhekeke ngaphansi kwengcindezi. Yingakho sibona ukwehluleka okuningi kwamavalvu ajwayelekile avaliwe nge-NBR kwezolimo zasezindaweni ezishisayo kanye namapayipi angaphandle. Lobu buthakathaka busebenza naku-ozone. I-Ozone ikhiqizwa ngokwemvelo ukukhanya kwelanga futhi isetshenziswa nakwezinye izinhlelo zokuhlanza amanzi ezithuthukisiwe. Ngisho nokugxila okuncane kwe-ozone kuzowohloka ngokushesha i-NBR. Ngamafuphi, ukusebenzisa i-NBR kunoma yikuphi ukusetshenziswa kwangaphandle ezindaweni ezishisayo kugembula ngokuthembeka komkhiqizo wakho kanye nedumela lakho.

Ingabe irabha ye-NBR imelana nokushisa ngempela ezindaweni ezishisayo?

Ubona isilinganiso sokushisa serabha ye-NBR ephepheni le-spec. Kodwa ingabe leso silinganiso sithembekile endaweni yangempela ye-tropical lapho amazinga okushisa asevele ephezulu kakhulu?

I-NBR imelana nokushisa okulinganiselwe, ngokuvamile kufika ku-120°C (248°F). Kodwa-ke, lo mkhawulo uyancipha ngokuvezwa okuqhubekayo. Ukuhlanganiswa kokushisa okuphezulu kanye nokushisa okusebenzayo ezindaweni ezishisayo kungasunduza i-NBR emikhawulweni yayo, okubangela ukwehluleka kwangaphambi kwesikhathi.

Ishidi lokucacisa lingadukisa uma lingafundwa ngokucophelela. Leso silinganiso esingu-120°C sivame ukuba ukushisa okuvamile, hhayi okungaguquki. Esimweni sezulu esishisayo, izinga lokushisa elizungezile lingase libe ngu-35°C kakade. Ivalvu ehlala elangeni eliqondile ophahleni ingafinyelela kalula amazinga okushisa aphezulu angu-70°C noma ngaphezulu, ngisho nangaphambi kokuba amanzi ashisayo ageleze kuyo. Lo mthwalo oshisayo oqhubekayo ubeka izinto ze-NBR ngaphansi kokucindezeleka okungapheli. I-EPDM, enesilinganiso sayo esijwayelekile esingu-150°C, inomkhawulo omkhulu wokuphepha. Ingabhekana kalula nokucindezeleka okuhlangene kokushisa okuphezulu okuzungezile kanye noketshezi lwenqubo eshisayo ngaphandle kokuwohloka. Lokhu okuphakeme kakhuluukuzinza kokushisaesinye isizathu esiyinhloko esisincoma kakhulu i-EPDM ukuze isebenze isikhathi eside ezindaweni ezishisayo.

Isifinyezo Sokusebenza Kwesimo Sezulu Sezimo Ezishisayo

Isiphetho

Ekusetshenzisweni kwamanzi asezindaweni ezishisayo, ukumelana kwe-UV nokushisa kwe-EPDM kubalulekile. Bhukha i-NBR kuphela ezinhlelweni zangaphakathi, ezivikelwe eziphatha uwoyela. Ukukhetha okulungile kuqinisekisa ukusebenza kwesikhathi eside nokwethembekile.