Qhov tsis yog - nce qia rooj vag valve yog ib pawg loj ntawm cov rooj vag li qub. Nws cov yam ntxwv tseem ceeb yog cov txiv ntoo qia yog nyob rau hauv lub valve lub cev thiab yog nyob rau hauv ncaj qha kev sib cuag nrog nruab nrab; lub rooj vag qhib thiab kaw los ntawm rotating qia. Txij li thaum lub qia tsuas tig tsis tau nce lossis poob, lub valve yuav tsum muaj qhov chaw tsawg dua, ua rau nws tsim nyog rau kev siv nrog kev txwv tsis pub. Vim tias lub qia tsis txav mus rau qhov ntsug, qhov qhib tsis tuaj yeem txiav txim siab los ntawm qhov ntev ntawm lub qia txuas mus rau sab nraud; yog li ntawd, yuav tsum tau qhib qhov taw qhia.
Raws li txoj kev sib txuas, lawv tuaj yeem muab faib ua cov xov (sab hauv xov) kev sib txuas (piv txwv li, threaded stainless hlau resilient-seated non- nce qia rooj vag li qub thiab Z15T-10 hauv threaded wedge gate li qub); flanged kev sib txuas (piv txwv li, txheem flanged rooj vag li qub thiab ntau yam flanged uas tsis yog{11}} nce qia qauv); thiab grooved kev sib txuas (xws li, grooved hluav taws- tiv thaiv tsis yog- nce qia rooj vag li qub thiab Z85X grooved mos- zaum tsis-nce qia rooj vag li qub).
Raws li txoj kev sib khi, lawv tuaj yeem muab faib ua cov tawv tawv- hom zaum (piv txwv li, resilient- zaum tsis yog- nce qia rooj vag li qub); mos- zaum hom (xws li, roj hmab- rooj vag li qub thiab mos- zaum tsis yog- nce qia rooj vag li qub); thiab wedge-sav hom (piv txwv li, wedge-hom non-nce qia rooj vag li qub).
Raws li txoj kev ua kom muaj zog, lawv tuaj yeem muab faib ua phau ntawv, hluav taws xob / hluav taws xob, thiab lwm yam tsav tsheb.
Raws li cov qauv siv tau lossis cov ntawv thov tshwj xeeb, lawv tuaj yeem muab faib ua cov qauv ua raws li National Standards (GB); cov qauv ua raws li API cov qauv (xws li API 6A siab-siab slab rooj vag li qub nrog tsis yog- nce stems); hluav taws- tiv thaiv li qub (piv txwv li, flanged lossis grooved hluav taws- tiv thaiv tsis yog- nce qia rooj vag li qub); thiab faus-cov kev pabcuam li qub (xws li, faus tsis yog{13}} nce qia rooj vag li qub).
Qhov sib txawv ntawm qhov tsis yog - nce qia rooj vag li qub thiab nce qia rooj vag li qub nyob rau hauv kev txav ntawm qia: nyob rau hauv tsis yog - nce qia rooj vag li qub, lub qia tsuas tig tsis muaj axial txav, thiab cov xov seem tseem nyob hauv lub cev valve.
