Ezi zivalo zisetyenziselwa ukulawula iintshukumo ze actuator kwaye ziyivale macala omabini. Ukuze ube nokuhla komthwalo phantsi kolawulo kwaye ugweme ubunzima bomthwalo obuthwalwayo i-valve iya kuthintela nayiphi na i-cavitation ye-actuator.
Ezi zivalo zifanelekile xa iivaluvu eziqhelekileyo zingasebenzi kakuhle njengoko zingakhathali kuxinzelelo lwangasemva.
Bakwavumela uxinzelelo lwenkqubo ukuhambisa ii-activators ezininzi kuthotho. Uhlobo "A" luhluke ngenxa yezikhundla zokuxhuma kunye nomlinganiselo womqhubi.