A particle size separator includes an upper separator frame, a lower separator frame, a screen disposed between the upper separator frame and the lower separator frame, a large size particle outlet having an inlet disposed below the screen, a small size particle outlet disposed in the lower separator frame and a combined baffle and seal unit disposed in an opening in the screen. The unit has a seal face configured to sealingly engage the inlet of the large size particle outlet. The unit has a baffle configured to constrain movement of particles on an upper surface of the screen into the inlet. The baffle is configured to sealingly engage an interior wall of the upper separator frame.