Belofo ea liphallelo, e tsejoang hape e le valve ea khatello ea khatello (PRV), ke mofuta oa valve ea tšireletso e sebelisetsoang ho laola kapa ho fokotsa khatello tsamaisong. Haeba khatello e ne e sa laoloe, e ka 'na ea eketseha' me ea baka tšitiso ea ts'ebetso, ho hlōleha ha lisebelisoa kapa thepa, kapa mollo. Ka ho nolofalletsa mokelikeli o hatelitsoeng hore o tsoe tsamaisong ka tsela e thusang, khatello e fokotsehile. Ho thibela likepe tsa khatello le lisebelisoa tse ling hore li se ke tsa ba tlas'a khatello e fetang meeli ea moralo oa tsona, thebelofo ea liphalleloe ahiloe kapa e hlophiselitsoe ho buloa ka khatello e behiloeng.

Thebelofo ea liphalleloe fetoha "tsela ea ho hanyetsa bonyane" ha khatello e behiloeng e fetisoa hobane valve e qobelloa ho buleha 'me metsi a mang a khutlisetsoa mocha o thusang. Motsoako oa mokelikeli, oa khase kapa oa mokelikeli o faposetsoang litsing tse nang le maro a tukang o ka khutlisoa kapa oa felloa ke moea.

[1] mohlomong e romelloa ka tsamaiso ea liphaephe e tsejoang e le hlooho ea mollo kapa hlooho ea liphallelo ho ea bohareng, e phahameng ea khase moo e chesoang teng, e ntša likhase tse tukang tse se nang letho sepakapakeng, kapa ka khatello e tlaase, tsamaiso e phahameng ea ho khutlisa mouoane.

[2] Lits'ebetsong tse se nang kotsi, mokelikeli o atisa ho lokolloa sepakapakeng ka pipework e loketseng ea ho ntša metsi e behiloeng sebakeng se sireletsehileng bakeng sa batho le e hahiloeng ho thibela ho kena ha pula, e ka amang khatello e behiloeng ea ho phahamisa. Khatello e tla emisa ho haha ​​ka har'a sekepe ha mokelikeli o lebisoa hape. Sephahla se tla koala ha khatello e fihla khatellong ea ho tsosolosa. Palo ea khatello e lokelang ho fokotseha pele valve e khutlela morao e tsejoa e le blowdown, eo hangata e hlalosoang e le peresente ea khatello e behiloeng. Li-valve tse ling li na le li- blowdown tse feto-fetohang, 'me ho fofa ho ka fetoha pakeng tsa 2% le 20%.

Ho eletsoa hore sets'oants'o sa valve ea ho thusa lits'ebetsong tsa khase e phahameng e be sebakeng se bulehileng. Ho buloa ha valve ea liphallelo ho tla baka khatello ea khatello tsamaisong ea liphaephe ho ea tlaase ho valve ea liphallelo lits'ebetsong moo phallo e hokahaneng le liphaephe. Hangata sena se bolela hore ha khatello e lakatsehang e finyelloa, valve ea liphallelo e ke ke ea ema hape. Li-valve tse bitsoang "differential" tsa liphallelo li sebelisoa khafetsa lits'ebetsong tsena. Sena se bontša hore khatello e sebetsa sebakeng se senyenyane haholo ho feta moo valve e bulang teng.

Khatello ea phallo ea valve e ka boloka valve e bulehile habonolo haeba valve e butsoe kaha khatello e tlameha ho theoha haholo pele valve e koala. Ha khatello ea tsamaiso ea lipeipi tsa ho ntša metsi e ntse e phahama, li-valve tse ling tsa liphallelo tse hokahaneng le tsamaiso ea liphaephe tsa ho tsoa li ka 'na tsa buleha. Sena ke ntho eo u lokelang ho e hopola. Sena se ka fella ka boitšoaro bo sa rateheng.