The suspension of solid material in a closed vessel has been studied. The vessel was designed as a pressure vessel having dished ends. Both the impeller speed at the off-bottom suspension point as well as the power demand related to this speed have been determined. In the study, emphasis was placed on studying the influence of both form and position of the baffles. It was found that a new dimensionless number, designed to describe the phenomena related to the suspension of particles, is a function of the impeller Reynolds number at the off-bottom suspension point. The impeller Reynolds number was varied between 10 000 and 800 000. Based on the results of this study, it can be stated that the design and position of the baffles are of great importance in minimizing the power demand in the suspension of particles. At the off-bottom suspension point, the power demand was lower for solid baffles when compared with baffles constructed of rods.