Isivimbeli sokubuyela emuva esisetshenziselwa ikakhulukazi ukuphakelwa kwamanzi ukusuka endaweni yasemadolobheni kuya endaweni evamile yokukhucululwa kwendle sikhawulela ngokuqinile umfutho wepayipi ukuze ukugeleza kwamanzi kube indlela eyodwa kuphela. Umsebenzi wayo ukuvimbela ukugeleza kwe-backflow medium yamapayipi noma yisiphi isimo sokugeleza kwe-siphon emuva, ukuze kugwenywe ukungcoliswa kokubuyela emuva.