The basics of seal technology and the influence of seals on the dynamics of centrifugal machines are described. Modeling, calculation and design of stuffing box and mechanical seals of centrifugal machines are presented. Designs, models and methods for calculating non-contact seals are considered, as well as an analysis of their influence on the vibration state of centrifugal machine rotors. The designs of automatic balancing devices as sealing units are described and their influence on the dynamics of centrifugal machines is analyzed. Special designs of non-contact seals, support seals and shaftless pumps are presented. General principles for constructing complex compaction systems for centrifugal machines are proposed, taking into account their influence on the vibration state.