Abstract: A diaphragm for use in a fluid flow chamber comprising a generally flat flexible sheet that is engageable at its periphery and has a central portion that is reciprocally movable along an axis perpendicular to a plane through the periphery, the flexible sheet having annular corrugations around the center portion, and a magnet secured to the center of the sheet, the magnet having a front and a rear, the corrugations causing the front and rear to maintain their orientation with respect to the axis as the central portion travels along the axis.

Abstract: A cleaning and/or disinfecting system for flushing water and chemical treatment liquids through the hydraulic circuitry of dialysate preparation and supply apparatus, the system employing, for each particular treatment liquid of a plurality of possible liquids, a keyhole adjacent to a chemical intake port and means to send electrical signals to an electrical controller indicating the presence of a key within a particular keyhole, whereby the particular treatment liquid connected to the port is flushed through the hydraulic circuitry of the apparatus at the proper flowrate and for the desired period of time.