Chisindikizo chaching'ono mkati mwa valavu yanu chimalephera, zomwe zimapangitsa kuti pakhale kutuluka madzi ambiri. Kulephera kosayembekezereka kumeneku kumabweretsa nthawi yogwira ntchito kwa makina, kuwonongeka kokwera mtengo, komanso makasitomala osasangalala omwe amadzudzula chinthu chanu chifukwa cha vuto.

Sankhani EPDM kuti mugwiritse ntchito madzi ambiri, makamaka ngati muli panja, muli ndi dzuwa, kapena muli ndi ozone. Sankhani NBR kuti mugwiritse ntchito mafuta, mafuta, mafuta, kapena madzi ochokera ku hydrocarbon. Kusankha koyenera kumadalira madzi ndi malo omwe ali.

Ndinkalankhula ndi mnzanga Budi za vuto lomwe m'modzi mwa makasitomala ake anali nalo. Iwo anali kupereka ma valve a ntchito yoweta nsomba ku Indonesia yomwe inkagwiritsa ntchitoopanga ozonikuti madzi akhale oyera. Patatha miyezi ingapo, ma valve anayamba kutuluka. Vuto silinali thupi la valve; linali ma seal a NBR omwe anali mkati. Ozone inali kuukira rabara, zomwe zinapangitsa kuti iwonongeke. Tinawalangiza kuti asinthe kukhala ma valve okhala ndi ma seal a EPDM, ndipo vutoli linathetsedwa nthawi yomweyo. Ndi zinthu zazing'ono izi zomwe zimatsimikizira kupambana kapena kulephera kwa polojekiti.

Ndi chiyani chabwino, EPDM kapena NBR?

Mukuwona njira ziwiri zotsekera valavu, ndipo njira ya NBR ndi yotsika mtengo. Mukuyesedwa kuti musankhe kuti muchepetse ndalama, koma mukuopa kuti mwina sichingakhale chisankho choyenera.

Zonsezi sizili bwino; zapangidwira ntchito zosiyanasiyana. EPDM ndi yabwino kwambiri polimbana ndi madzi, nyengo, komanso kutentha. NBR ndi yabwino kwambiri polimbana ndi mafuta, mafuta, ndi mafuta.

Kuganiza kuti chinthu chimodzi ndi "chabwino" ndi cholakwika chofala. Kusankha kumeneku ndi kokhudzana ndi kugwirizanitsa mankhwala.EPDM (Ethylene Propylene Diene Monomer)Ili ndi kapangidwe kokhazikika ka mankhwala komwe kamaipangitsa kuti ikhale yolimba kwambiri ku nyengo, kuwala kwa dzuwa (UV), ozone, komanso madzi otentha ndi ozizira. Izi zimapangitsa kuti ikhale chisankho chabwino kwambiri pamafakitale ambiri okhudzana ndi madzi monga kuthirira, maiwe osambira, ndi mapaipi wamba.NBR (Nitrile Butadiene Rabber)Kumbali ina, imadziwika kuti imakana mafuta, mafuta, ndi mafuta ochokera ku mafuta. Komabe, imasweka msanga ikakumana ndi ozone ndi kuwala kwa UV. Chifukwa chake, ngati valavuyo ndi ya mzere wamadzi, EPDM ndiye chisankho chabwino kwambiri. Ngati ndi ya mafuta ogwiritsira ntchito makina kapena mankhwala enaake, NBR ndiye yankho lokhalo lolondola.

Kodi kusiyana pakati pa EPDM ndi PVC rabara ndi kotani?

Kasitomala wanu akufunsa za "rabala" mu valavu. N'zosavuta kusokonezeka pakati pa pulasitiki yolimba ya thupi la valavu ndi zinthu zosinthasintha zomwe zimagwiritsidwa ntchito popangira zomangira mkati mwake.

Ndi zipangizo zosiyana kwambiri pa ntchito zosiyanasiyana. PVC ndi thermoplastic yolimba yomwe imagwiritsidwa ntchito popanga thupi la valavu ndi mpira. EPDM ndi rabara yopangidwa yosinthasintha yomwe imagwiritsidwa ntchito popanga mphete za O ndi mipando yomwe imapanga chisindikizo.

Iyi ndi mfundo yosokoneza nthawi zambiri. Tiyeni tipange zinthu zosavuta. Taganizirani za valavu ngati chitseko. PVC ndi chimango cholimba komanso cholimba cha chitseko komanso chitseko chokha. Imapereka kapangidwe ndi mphamvu. EPDM ndi chotchingira rabara chosinthasintha chomwe chimaphimba chimangocho. Mukatseka chitseko, chotchingira cha nyengo chimakanikiza kuti chipange chisindikizo chabwino komanso chosalowa madzi. Simungathe kupanga chitseko pogwiritsa ntchito chotchingira cha nyengo, ndipo simungathe kupanga chisindikizo chosinthasintha kuchokera ku chimango cholimba cha chitseko. Mu mavavu athu, PVC imapereka nyumba yolimba yolimba. EPDM imapereka ziwalo zofewa, zosinthasintha mkati zomwe zimaletsa kuyenda kwa madzi. Palibe chinthu chotchedwa "PVC rabara" m'mavavu awa; zisindikizo ndi chinthu chosiyana, chapadera.

Kodi kusiyana pakati pa EPDM ndi NBR 70 ndi kotani?

Mukuyang'ana pepala lofotokozera ndipo onani “NBR 70″. Mukudziwa kuti NBR ndi chiyani, koma simukudziwa tanthauzo la nambala “70″ kapena momwe imafananira ndi EPDM.

"70" mu NBR 70 imatanthauza durometer yake, kapena kuti hardness rating. Imasonyeza momwe rabala ilili yolimba. EPDM ndi NBR zonse zimabwera mu hardness zosiyanasiyana, ndipo 70 Shore A ndi muyezo wofanana.

Chiwerengerocho sichili mbali ya mtundu wa chinthucho; ndi muyeso wa makhalidwe ake enieni. Kulimba kwa rabara zofewa kumayesedwa pa "Gombe A"Sikelo." Durometer ya 70 ndi yovuta kwambiri, pakati pa msewu. Ndi yolimba mokwanira kuti isasunthidwe pamalo pake chifukwa cha kupanikizika koma imakhala yosinthasintha mokwanira kuti ipange chisindikizo chabwino. Mutha kupeza NBR 50 (yofewa) kapena NBR 90 (yovuta kwambiri). Zomwezo zikugwiranso ntchito pa EPDM; mutha kukhala ndi EPDM 70. Chifukwa chake, kufananiza kwenikweni nthawi zonse kumakhala pakati pa zinthu zoyambira—EPDM motsutsana ndi NBRNambala ya kuuma imakuuzani ngati ikugwirizana ndi kuthamanga kwa makina anu. Pazinthu zambiri zomwe zimagwiritsidwa ntchito m'madzi ndi mpweya, chisindikizo cha 70 durometer chimapereka magwiridwe antchito abwino komanso kulimba.

Kodi kutentha kwa EPDM poyerekeza ndi NBR ndi kotani?

Muyenera kusankha valavu ya makina omwe angatenthe kwambiri padzuwa kapena kuzizira kwambiri m'nyengo yozizira. Kusankha chisindikizo chomwe sichingathe kupirira kutentha kungapangitse kuti chikhale chofooka komanso chotayikira.

EPDM ili ndi kutentha kwapamwamba kwambiri, nthawi zambiri kuyambira -50°C mpaka 150°C (-58°F mpaka 302°F). NBR ili ndi kutentha kochepa, nthawi zambiri kuyambira -40°C mpaka 120°C (-40°F mpaka 248°F).

Kuchita bwino kwa kutentha ndi chifukwa chachikulu chomwe EPDM nthawi zambiri imakhala chisankho chabwino kwambiri. Kutha kwake kukhala wosinthasintha kutentha kumakhala kodalirika kwambiri m'malo ozizira. Kutentha kwake kwakukulu kumatanthauza kuti imatha kuthana ndi mitsinje yamadzi otentha ndipo sizingawonongeke kwambiri ndi zida zomwe zimakhala padzuwa lotentha. NBR, ngakhale ili yabwino, imatha kukhala yolimba komanso yofooka ikazizira kwambiri, zomwe zingasokoneze kuthekera kwake kotseka. Pa kutentha kwambiri, imatha kukalamba ndikulimba mwachangu kuposa EPDM. Ichi ndichifukwa chake ku China, ma valve ambiri otsika mtengo amagwiritsa ntchito NBR, koma nthawi zonse timalimbikitsa EPDM pakugwiritsa ntchito kulikonse komwe kumayang'anizana ndi kutentha kwambiri kapena kufunikira kudalirika kwa nthawi yayitali.

Kuyerekeza Mwachangu kwa Zinthu Zosindikizidwa

Mapeto

Pa madzi, nyengo, ndi kutentha kwambiri, sankhani EPDM. Pa mafuta ndi mafuta, sankhani NBR. Kugwirizanitsa chisindikizo ndi ntchito yake ndiye chinsinsi cha valavu ya PVC yodalirika, yokhalitsa, komanso yopanda kutuluka madzi.