The product to be weighed is stored in the upper bunker, and then the filling process begins with the opening of the pneumatic cover on the scale and one of the high and low product carrying capacity runs simultaneously, the spiral with the highest product carrying capacity stops in the last precise dosing process and the spiral with less product carrying capacity It continues to work, filling the sack, which is held in the lower pan by the clamping mouth connected to the pneumatic pistons, so that the desired weighing ratio is obtained in the last case in precise dosing.