Abstract: A rate of flow regulator comprising upper and lower fluid chambers, the upper chamber having a double acting float valve to maintain a predetermined level of fluid therein, vent means venting each chamber to atmosphere, and metering means for regulating fluid flow to the lower chamber, the height of said upper chamber being adjustable relative to said metering means to change the fluid flow rate.

Abstract: A device for exchange between fluids, shown especially adapted for exchange between blood and a treatment fluid. The device comprises a first set of fluid channels for blood and a second set of channels for a treatment fluid. Each channel of the first set is defined by a pair of panels of semi-permeable membrane which are supported along spaced-apart lines by supports. At least a portion of the channels of the second set are defined by a pair of membrane panels and a pair of the supports. Each set of channels is arranged into a plurality of layers, the layers alternating between channels of the first and second sets. The resulting three dimensional array of blood and treatment fluid paths enables strict channeling to ensure equal exposure and flow of all blood and treatment fluid while simultaneously achieving double exposure of the treatment fluid as it flows between layers of blood.