Ivalve yokukhutshwa komoya edibeneyo enesantya esiphezulu yenziwe ngamacandelo amabini: Ivalve yokukhutshwa komoya yoxinzelelo oluphezulu lwediaphragm kunye nevalve yokukhupha umoya yoxinzelelo oluphantsi. Ivalve yomoya yoxinzelelo oluphezulu ikhupha ngokuzenzekelayo umthamo omncinci womoya oqokelelwe ngaphakathi kombhobho phantsi koxinzelelo. Ivalve yomoya yoxinzelelo oluphantsi inokukhupha umoya kumbhobho xa umbhobho ongenanto uhanjiswa ngamanzi, kwaye uvule ngokuzenzekelayo kunye nokungena komoya kumbhobho ukuphelisa isitshixo xa umbhobho ukhutshiwe okanye uvacuum okanye phantsi kwemeko yokwahlulwa kwekholamu yamanzi.