Based on a non-orderly flow of supplied articles, which may also be sticky articles of food, there is effected in a compulsory manner an isolation of mutually separated small article portions, which are moved through a weighing station (20) and thereafter brought together, selectively, into larger portions, e.g. with a predetermined weight. In a preferred system according to the invention use is made of an endless row of carrier trays (12) which, in two straight runs, pass along a number of receiver containers (22), into which they are selectively emptied after having passed the weighing station. In front of this station distributor means (14, 18) are provided above a horizontal reversing path of the tray chain for ensuring that the supplied articles are distributed to the trays without overlapping therebetween. Various advantageous embodiments of the single parts of the system are described, including a special weighing station enabling the system to work with a desirably high capacity. According to choice, the system may be used for sorting purposes or for the building up of article portions according to batching or combination weighing principles.