Ivalve yentsimbi edityaniswe ngokupheleleyo iyivalve eqhelekileyo, eyona nto iphambili kukuba ngenxa yokuba ibhola kunye nomzimba wevalve udityanisiwe ube sisiqwenga esinye, ivalve ayilula ukuvelisa ukuvuza ngexesha lokusetyenziswa.Ubukhulu becala yenziwe ngumzimba wevalvu, ibhola, isiqu, isihlalo, igasket njalo njalo.Isiqu siqhagamshelwe kwivili lesandla sevalve ngebhola, kwaye ivili lesandla liyajikeleziswa ukujika ibhola ukuze ivule kwaye ivale ivalve.Izixhobo zokuvelisa ziyahluka ngokusetyenziswa kweendawo ezahlukeneyo, imidiya, njl.