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AssigneeWaters Technologies Corporation
InventorsJoshua A. Shreve, Steven J. Ciavarini
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Described is a method of reducing liquid composition errors in a low-pressure mixing pump system. Packets representing the switching intervals of each component of the desired fluid mixture are provided to an intake of the mixing pump system. For each packet, a switching time associated with at least one of the components in the packet is modulated. Modulated switching times are based on time offsets that are specifically selected according to the undesirable frequency characteristic of an intake response of the mixing pump system. The average of the volumes contributed by the packets thus modulated is equal to a component volume that achieves a desired proportion of the component in the output flow of the mixing pump system. Modulated switching times enable the reduction or elimination of composition error in the output flow of the mixing pump system.
A method of reducing composition error in the output flow of a mixing pump system, the method comprising, for each packet in a plurality of packets provided to an intake of the mixing pump system, modulating a switching time of at least one component in a plurality of components in the packet, the modulated switching times being determined from a plurality of switching time offsets, wherein the switching time offsets are determined in response to a frequency characteristic of an intake response of the mixing pump system.
Dependencies are inferred from the claim text.