Method and system for matching flow rate

摘要

A flow rate of unconnected first and second fluid flows is matched, such as, but not limited to, matching the flow rate of the replacement water stream with the waste water stream in kidney dialysis. The first and second flow paths (10 and 12) are interconnected so substantially the same flow from a positive displacement pump (16) in the first path encounters a flow-rate transducer (20) in the second path. Transducer readings are taken for various values of the controllable pump speed of the pump. Then, the first and second flow paths are disconnected, a transducer reading is taken, and the flow rate of the fluid flow in the first flow path is controlled by controlling the pump speed using the value of the pump speed from the previous interconnected paths which corresponds to the value of the transducer reading from the previous interconnected paths which matches the transducer reading for the disconnected paths.