For the  severe VOD treatment a Danieli Centro Met Vacuum Tank Degasser is  preferable to a ladle lid system. A water cooled lance with a 3 laval tuyere is used to blow the oxygen into the bath. During VOD treatment a special splash cover is put on top of the ladle to keep  steel and slag inside the ladle during the very intense boiling  reaction. Such a splash cover cannot be included in the ladle lid  system.