Impact separators of different shapes and designs are gaining importance as alternatives to cyclones for gas-solid separation in circulating fluidized bed boilers. In the present study, pressure drop and collection efficiency of simple plate type impact separators are experimentally investigated. Effects of air velocity, solid loading and included angle of impact blades on these two performance parameters are discussed. How the collection efficiency depends on the particle size is also shown. Experimental results demonstrate that this gas-solid separator has compact structure, low pressure drop and satisfactory collection efficiency especially at low air velocity, high solid loading and for smaller and larger particles of the sand used in the experiment.