Olu luhlu ziivalvu eziphindwe kabini. Ngokusebenzisa ezi zivalo ziyakwazi ukulawula imithwalo ye-bidirectional, ukuqinisekisa ukuzinza kwindawo yokusebenza kunye nokulawula ukuhamba kwazo nangona kukho imithwalo ye-gravitational engenzi uxinzelelo. Ivalve...