Abstract: A fluid classifier for separating particles from a lading for operation with a lading tank including a filter unit for mounting in the tank and having capillary passages for fluid flow from the tank externally of the filter unit to the interior of the filter unit for providing a pressure differential across the capillary passages resulting from a difference in fluid level in the tank and within the filter unit, a drive for rotating the filter unit in the tank, and a pump for pumping fluid from filter unit interior to the outlet. Ultrasonic transducers positioned along the filter unit for agitating the lading adjacent the capillary passages. A method of controlling fluid flow through the capillary passages.

Abstract: In chlorinating a swimming pool equipped with a periodically operating pump arranged to circulate water from the pool through a filter assembly and back to the pool, chlorination of the pool water is accomplished by the use of a solid chlorinating material. The chlorinating material is introduced into an openable airtight chamber which has a water inlet to and a water outlet from the chamber at the bottom thereof. To prepare the chamber for insertion of chlorinating material, a valve in a duct to the water inlet is closed and a check valve associated with the outlet prevents backflow of water into the chamber so that before opening the chamber air previously contained in the chamber from a prior loading of chlorinating material expands in the chamber to express water from the chamber through the outlet, thereby providing an essentially dry chamber. The chamber is then opened and additional chlorinating material is placed therein. The chamber is then first closed and the valve to the inlet is opened.