Abstract: A ball collecting apparatus for a pipe cleaning system utilizing circulating foam rubber balls includes a cylindrical housing having a rotary ball retaining screen disposed therein which is movable between a ball circulating position, a ball collecting and holding position, and a ball discharging position in a simple and efficient manner. In its recirculating position, a screen is disposed to permit the balls to flow directly from the housing inlet to the housing outlet for recirculation without interruption. When rotated to the collecting and holding position, the screen retains the balls thereon, prevents their passage through the housing outlet and preferably also prevents inadvertent entry of the balls into a ball discharge outlet. The discharge outlet is located near the bottom of the housing and rotation of the screen to the ball discharging position, along with appropriate closure of the flow inlet and outlet oepnings, allows the collected balls to be discharged by gravity and removed the system.