Njengoko iimfuno zabantu zokhuseleko lokusingqongileyo ziya zisiba ngqongqo ngakumbi, iimfuno zezivalo nazo ziya zisanda, kwaye iimfuno zomgangatho ovuzayo ovumelekileyo wemithombo yeendaba eziyityhefu, ezivuthayo neziqhumayo kwizityalo zepetrochemical ziya ziba ngqongqo ngakumbi nangakumbi.Iivalvu zizixhobo eziyimfuneko kwizityalo zepetrochemical., Iindidi zayo kunye nobuninzi zikhulu, kwaye yenye yemithombo ephambili yokuvuza kwisixhobo.Kwimithombo yeendaba ezinobuthi, ezinokutsha kunye neziqhushumbisi, iziphumo zokuvuza kwangaphandle kwevalve zinobuzaza ngakumbi kunokuvuza kwangaphakathi, ngoko ke iimfuno zokuvuza zangaphandle zevalve zibaluleke kakhulu.Ukuvuza okuphantsi kwevalve kuthetha ukuba ukuvuza kwangempela kuncinci kakhulu, okungenakumiselwa ngoxinzelelo lwamanzi oluqhelekileyo kunye neemvavanyo zokutywinwa koxinzelelo lomoya.Ifuna iindlela ezingaphezulu zenzululwazi kunye nezixhobo eziphucukileyo zokubona ukuvuza okuncinci kwangaphandle.

Imigangatho eqhelekileyo esetyenziswayo yokubona ukuvuza okuphantsi yi-ISO 15848, i-API624, indlela ye-EPA 21, i-TA luft kunye neNkampani ye-Oli ye-Shell SHELL MESC SPE 77/312.

Phakathi kwabo, udidi lwe-ISO A lunezona mfuno ziphezulu, zilandelwa yi-SHELL iklasi A. Ngeli xesha,I-NSEN ifumene ezi satifikethi zisemgangathweni zilandelayo;

ISO 15848-1 iklasi A

API 641

TA-Luft 2002

Ukuze kuhlangatyezwane neemfuno zokuvuza okuphantsi, iivalve castings kufuneka zihlangabezane neemfuno zovavanyo lwegesi yehelium.Ngenxa yokuba ubunzima beemolekyuli ze-helium buncinci kwaye kulula ukungena, umgangatho wokuphosa ungundoqo.Okwesibini, isitywina phakathi komzimba wevalve kunye nesigqubuthelo sokugqibela sihlala sisitywina se-gasket, esitywina esimile, esilula ukuhlangabezana neemfuno zokuvuza.Ngaphaya koko, itywina kwisiqu sevalvu litywina eliguqukayo.Iinqununu zegraphite zithathwa ngokulula ngaphandle kokupakisha ngexesha lokuhamba kwe-valve stem.Ngoko ke, ukupakisha okukhethekileyo okuvuzayo okuphantsi kufuneka kukhethwe kwaye ukucocwa phakathi kokupakisha kunye ne-valve stem kufuneka kulawulwe.Ucoceko phakathi komkhono woxinzelelo kunye nesiqu sevalve kunye nebhokisi yokuhlohla, kunye nokulawula uburhabaxa bokulungiswa kwesikhondo sevalve kunye nebhokisi yokuhlohla.