Patent ID: 6970248

Claim:
A method for detecting a characteristic of a flow of a liquid in a pipe for intended use in determining a transition point among two products forming the flow, comprising: (a) obtaining a first signal representative of the characteristic of the flow; (b) transforming the first signal into a measurement proportional to the characteristic; (c) repeating steps (a) and (b) until a plurality of measurements are obtained; (d) evaluating the measurements to determine whether the flow is in a stationary stage representing the presence of only one product or a transition stage representative of the presence of two products; (e) when in the transition stage, continuously determining a rate of change in a selected group of the plurality of measurements including measurements obtained during the transition stage; (f) determining when the rate of change of the selected group is at a maximum value; and (g) generating a second signal indicative of the transition point when the rate of change in a predetermined number of measurements in the selected group is less than the maximum value.