Valavu Yowunikira

Valavu yofufuzira idapangidwa ndikupangidwa motsatira zofunikira za API 6A 《Zipangizo Zofunikira za Wellhead ndi Mtengo wa Khirisimasi》, zomwe zitha kugwiritsidwa ntchito mosinthana ndi zida zofananira kunyumba ndi kunja zomwe zikugwirizana ndi API 6A Standard. Pakati pake pamakhala chitsulo chokana sulfide ndipo chingagwiritsidwe ntchito mu mkhalidwe wa H2S, thupi la vavu lopangidwa ndi chitsulo chopangidwa ndi alloy chomwe chimagwira ntchito bwino. Mitundu iwiri ya mavavu owunikira amaperekedwa ndi landrill: Mtundu wa Swing ndi Mtundu wa Lift.