Method for determining a flow rate at a liquid delivery system, method for determining an amount of energy of a pumped liquid, liquid delivery system and pump

摘要

A method is proposed for determining a flow rate on a liquid delivery system in which a liquid is conveyed by a pump, the pump comprising an electric motor and operating the electric motor, the electric motor is operated at a first speed and from a measured engine power and the rotational speed determining the flow rate, comprising: - increasing the first speed to a second speed which is greater than the first speed; - Determining a second flow rate at the second speed from the engine power and the second speed; - Determining a third flow rate from the second flow rate by extrapolation from the second speed to the first speed, wherein the third flow rate is the target size; and - after determining the second flow rate (Q (n2)) reduction of the speed (n) back to the first speed (n1).