Ivalve yokukhulula, eyaziwa ngokuba yi-valve yokunciphisa uxinzelelo (PRV), luhlobo lwevalve yokhuseleko olusetyenziselwa ukulawula okanye ukunciphisa uxinzelelo kwinkqubo. Ukuba uxinzelelo belungalawulwa, lunokwakha kwaye lubangele ukuphazamiseka kwenkqubo, isixhobo okanye ukusilela kwesixhobo, okanye umlilo. Ngokwenza ukuba i-fluid ixinzelelwe ukuba iphume kwinkqubo ngokusebenzisa indlela yokuncedisa, uxinzelelo luyancitshiswa. Ukuthintela iinqanawa zoxinzelelo kunye nezinye izixhobo ukuba ziphantsi koxinzelelo oludlula imida yoyilo, iivalve yokukhululayakhiwe okanye icwangciswe ukuba ivuleke kuxinzelelo oluchaziweyo.

Iivalve yokukhululaiba "yindlela yokuchasana okuncinci" xa uxinzelelo olumiselweyo lugqithiswa ngenxa yokuba i-valve inyanzelekile ukuba ivuleke kwaye enye i-fluid iphinda iqondiswe kumjelo oncedisayo. Ulwelo, irhasi, okanye umxube werhasi engamanzi othi ujikwe kwiinkqubo ezinolwelo olunokutsha unokuphinda ubangwe okanye uphume umoya.

[1] mhlawumbi ithunyelwa ngenkqubo yemibhobho eyaziwa ngokuba yi-flare header okanye i-header yokunceda kwindawo esembindini, ephakamileyo yokudangala kwerhasi apho itshiswe khona, ikhupha iirhasi zokutsha ezingenanto kwi-atmosfera, okanye ngoxinzelelo oluphantsi, inkqubo yokubuyisela umphunga.

[2] Kwiinkqubo ezingekho yingozi, ulwelo lukhutshwa rhoqo kwi-atmosfera ngokusebenzisa umbhobho wokukhupha ofanelekileyo obekwe ngokukhuselekileyo kubantu kwaye wakhelwe ukuthintela ukungena kwemvula, okunokuthi kube nefuthe kuxinzelelo lokunyuswa kweseti. Uxinzelelo luya kuyeka ukwakha ngaphakathi kwinqanawa njengoko ulwelo luqondiswa kwakhona. Ivalve iya kuvala xa uxinzelelo lufikelela kuxinzelelo lokubuyisela kwakhona. Ubungakanani boxinzelelo ekufuneka buncitshiswe phambi kokuba ivalve ihlaziywe kwaziwa ngokuba yiblowdown, edla ngokuchazwa njengepesenti yoxinzelelo olubekiweyo. Ezinye iivalvu zinee-blowdowns ezilungelelanisiweyo, kwaye i-blowdown inokutshintsha phakathi kwe-2% kunye ne-20%.

Kucetyiswa ukuba indawo yokuphuma kwevalvu yoncedo kwiinkqubo zegesi yoxinzelelo oluphezulu ibe kwindawo evulekileyo. Ukuvulwa kwevalve yokunceda kuya kubangela ukunyuswa koxinzelelo kwinkqubo yemibhobho ezantsi komjelo wevalve yokukhulula kwiinkqubo apho i-outlet iqhagamshelene nemibhobho. Oku kuthetha ukuba xa uxinzelelo olufunwayo lufunyenwe, ivalve yokukhulula ayiyi kuphinda ibuyele. Izinto ezibizwa ngokuba “ziivalvu ezahlukeneyo” zisetyenziswa rhoqo kwezi nkqubo. Oku kubonisa ukuba uxinzelelo lusebenza kuphela kwindawo encinci kakhulu kunokuvulwa kwevalve.

Uxinzelelo lokuphuma kwevalve lunokugcina ivalve ivulekile ukuba ivalve ivuliwe kuba uxinzelelo kufuneka lwehle kakhulu phambi kokuba ivalve ivale. Njengoko uxinzelelo lwenkqubo yombhobho wokukhupha lukhuphuka, ezinye iivalve zokunceda ezidityaniswe nenkqubo yombhobho wokukhupha zingavula. Le yinto ekufuneka uyikhumbule. Oku kunokukhokelela ekuziphatheni okungafunekiyo.