Patent ID: 6296450
Filing Date: 2001-10-02
Classification: F04B

Abstract:
A system for pumping a fluid having a density comprisinga pump having a known stroke volume (SV), which is essentially constant,an actuator interacting with the pump during a stroke interval (T.sub.Stroke) to pump fluid through the pump,a receptacle to dispense fluid into the pump or to receive fluid pumped from the pump,a weigh sensor to detect changes in weight of the receptacle over a sample time period, anda controller coupled to the actuator and the weigh sensor and including a control function to achieve a desired flow rate (Q.sub.Desired) by deriving an actual flow rate (Q.sub.Actual) by sensing with the weigh sensor changes in weight of the receptacle over the sample time period, taking into account the density of the fluid, and adjusting the stroke interval based upon Q.sub.Actual so that Q.sub.Desired is achieved.