This paper reviews the theoretical work on dust explosions developed by the authors. The bases of the work are a simplified model of the dust cloud suspension, the flame propagation process and the combustion of solid particles. As a result, characteristics of the phenomena are expressed by combining reaction kinetics, heat transfer theory and thermodynamics. Further, theoretical information on some protection methods is derived and shown to be safe. It thus appears that, although this treatment includes some severe assumptions, it could provide a basis for more rigorous theories for prediction of dust explosion and design of protection systems.