Abstract: A sluice apparatus intended for dosed introduction of abrasive or rubbing elements into, and removal from, a liquid-carrying pipe or tube line system includes a drum-like collecting vessel with three connecting valves--namely, two continuous flow valves and one catcher valve. Disposed inside the vessel is an apertured catcher basket which is spaced from the inside wall of the vessel and which has the geometry of a partial drum with two side plates. Its upper end is secured by means of holding tubes adapted to be supported on holding pins so that the basket can be easily inserted and withdrawn.