Umsebenzi we-valve uvemvane kagesi uzosetshenziswa njengevalve yokunqamula, ivalvu yokulawula kanye nevalvu yokuhlola ohlelweni lwamapayipi.Ibuye ifaneleke kwezinye izikhathi ezidinga ukulawulwa kokugeleza.Kuyiyunithi yokubulawa ebalulekile emkhakheni wokulawula okuzenzakalelayo kwezimboni.