Valavu yowunikira yozungulira, mavavu osabwerera, apangidwa kuti aletse kutembenuka kwa kayendedwe ka madzi mu dongosolo la mapaipi. Mavavu awa amayatsidwa ndi zinthu zomwe zimayenda mupaipi.Kupanikizika kwa madzi omwe amadutsa mu dongosolo kumatsegula valavu, pomwe kutembenuka kulikonse kwa kayendedwe ka madzi kudzatseka valavu.Kutseka kumachitika ndi kulemera kwa makina owunikira, ndi kupanikizika kwa msana, ndi kasupe, kapena kuphatikiza njira izi.

Valavu yoyesera ya Swing 800lbs  Ndi ya ma valve ang'onoang'ono oyezera kuthamanga kwambiri, omwe amapangidwa ndi chitsulo chopangidwa. Nthawi zambiri timawapanga mu swing check valve, piston check valve (lift check valve).Imapezeka m'mapangidwe atatu a maboni. Kapangidwe koyamba ndi Bolted Bonnet, yokhala ndi cholumikizira cha amuna ndi akazi, chozungulira, chopangidwa mu F316L/graphite. Gasket ya mphete imapezekanso ngati mungafune. Kapangidwe kachiwiri ndi boniti yolumikizidwa, yokhala ndi cholumikizira cholumikizidwa ndi ulusi ndi chotseka. Mukapempha cholumikizira champhamvu cholowera chikupezeka, kapangidwe komaliza ndi boniti yotsekedwa ndi kukakamiza, yomwe ndi kapangidwe ka ma valve opanikizika kwambiri.