CONTROL OF A FLOW GENERATOR IN A TANK

The invention relates to a method for controlling a flow generator (1) in a tank (20) configured for housing a liquid comprising solid matter, the flow generator (1) comprising an impeller and being located at a height (h-mixer) in the tank (20) and the tank (20) having a predetermined maximum filling height (h-max), wherein the flow generator (1) is configured to be operated at a variable operational speed (n) and the demand of operational speed (n-demand) is dependent on the present liquid level height (h-present) in the tank (20), wherein a max operational speed (n-max) of the flow generator (1) is the operational speed required when the liquid level in the tank (20) is equal to the maximum filling height (h-max), the present operational speed (n-present) being set equal to the demand of operational speed (n-demand) of the flow generator (1) that is determined using the formula: n−present=n−demand=−−−−−−−−−−h−max/h−present∧an−max at least when [(h-mixer) + X] ≤ (h-present) ≤ (h-max), wherein a ≥ (1/4) and a ≤ 2, X = radius of the impeller of the flow generator + 1, and all heights and measures are given in meter.