Abstract: Means of sealing off the inside of a pulverizer, especially a bowl-mill pulverizer that has a horizontal rotating bowl-type grinding ring rigidly connected to a shaft, from the outside atmosphere. The means comprise a barrier-air chamber and ring seals in a ring-seal holder. The ring seals are slide rings that fit into grooves. They demarcate the barrier-air chamber. The ring seal on the side of the chamber that faces the inside of the pulverizer does not fit as tightly against its opposing surface (the shaft in one embodiment) as those on the other side.