I-valve yokusiza, eyaziwa nangokuthi i-valve yokusiza ingcindezi (i-PRV), iwuhlobo lwevalvu yokuphepha esetshenziselwa ukulawula noma ukunciphisa ingcindezi ohlelweni.Uma ingcindezi ibingalawulwa, ingase yakheke futhi ibangele ukuphazamiseka kwenqubo, ukwehluleka kwethuluzi noma okokusebenza, noma umlilo.Ngokuvumela uketshezi olucindezelwe ukuba luphume ohlelweni ngokusebenzisa indlela yokusiza, ukucindezela kuyancishiswa.Ukuvimbela imikhumbi yokucindezela nezinye izinto zokusebenza ekucindezelekeni okweqa imingcele yazo yokuklama, ii-valve yokusizayakhiwe noma ihlelwe ukuthi ivuleke ngengcindezi ebekiwe.

Ii-valve yokusizaiba “indlela yokumelana okuncane” lapho ukucindezela okumisiwe kweqiwa ngenxa yokuthi i-valve iphoqelelwa ukuvuleka futhi olunye uketshezi luqondiswe kabusha kumgudu wokusiza.Ingxube ye-liquid, igesi, noma i-liquid-gas ephambukiswe kumasistimu anoketshezi oluvuthayo iyabuyiswa noma ifakwe umoya.

[1] kungenzeka ukuthi ithunyelwa ngohlelo lwamapayipi olwaziwa ngokuthi unhlokweni wokuvuleka noma unhlokweni wokusiza endaweni emaphakathi, ephakeme evuthayo lapho ishiswa khona, ikhiphe amagesi avuthayo angenalutho emkhathini, noma ngomfutho ophansi, uhlelo lokuthola umhwamuko ogeleza kakhulu.

[2] Ezinhlelweni ezingezona eziyingozi, uketshezi luvamise ukukhishelwa emkhathini kusetshenziswa amapayipi okukhipha amanzi afanelekile abekwe endaweni ephephile kubantu futhi akhelwe ukuvimbela ukungena kwemvula, okungaba nomthelela ekucindezelweni okusethiwe kokuphakanyiswa.Ingcindezi izoyeka ukwakha ngaphakathi komkhumbi njengoba uketshezi luqondiswa kabusha.I-valve izovala lapho ingcindezi ifinyelela ingcindezi yokuvuselela kabusha.Inani lokucindezela okufanele lincishiswe ngaphambi kokuba i-valve iphinde imiswe kabusha laziwa ngokuthi i-blowdown, evame ukuvezwa njengephesenti lokucindezela okumisiwe.Amanye ama-valve afaka ama-blowdowns alungisekayo, futhi i-blowdown ingashintshashintsha phakathi kuka-2% no-20%.

Kuyelulekwa ukuthi indawo yokuphuma kwevalvu yokusiza ezinhlelweni zegesi enomfutho ophezulu ibe semkhathini ovulekile.Ukuvulwa kwevalvu yokukhulula kuzodala ukunqwabelana kwengcindezi ohlelweni lwamapayipi ezansi nomfula wevalvu yokukhulula ezinhlelweni lapho indawo yokuphuma ixhunywe kumapayipi.Lokhu ngokuvamile kusho ukuthi lapho ingcindezi oyifunayo ifinyelelwa, i-valve yokusiza ngeke iphinde iqale.Ama-valve okusiza abizwa ngokuthi “omehluko” avame ukusetshenziswa kulezi zinhlelo.Lokhu kubonisa ukuthi ingcindezi iyazikhandla kuphela endaweni encane kakhulu kunokuvulwa kwevalvu.

Ukucindezela kokuphuma kwe-valve kungagcina i-valve ivulekile kalula uma i-valve ivuliwe kusukela ukucindezela kufanele kwehle kakhulu ngaphambi kokuba i-valve ivale.Njengoba ingcindezi ohlelweni lwepayipi yokukhipha umoya ikhuphuka, amanye ama-valve okusiza axhunywe ohlelweni lwamapayipi okukhiphayo angase avuleke.Lokhu kuyinto okufanele uyikhumbule.Lokhu kungase kuphumele ekuziphatheni okungafuneki.