a device for treating preforms to obtain containers made of plastics , for example bottles for food applications , comprising an ejector adapted to pick up and release one or more preforms , arranged so that their neck is directed upwardly , a heating conveyor , and a unit for transferring the preforms unloaded from the heating conveyor , which is adapted to modify their spacing and speed , adapting them to the spacing and speed of an adjacent and axially offset blow - molding conveyor to which the one or more preforms are transferred .