From our French patent application No. 7803475, U.S. patent application Ser. No. 3,414 filed Jan. 15, 1979, now U.S. Pat. No. 4,288,263 it is known that the reservoir front and rear walls are made from plates and that the side walls consist of lateral moving bands which move with the conveyor and which bear against the side edges of the front and rear plates. The reservoir is fed through nozzles which pass through the front plate, discharging into the reservoir and produce nearly horizontal mixing streams, oriented in the opposite direction from the direction of advance of the conveyor. The front plate is slightly raised so as to form a pouring slot between its lower edge and the conveyor. In order to prevent massive setting within the product contained in the reservoir and on the walls of said reservoir, the mixture is introduced through the feed nozzles at a given rate, fast enough to provide stirring inside the reservoir, and the front and rear plates are caused to vibrate with the help of vibrators mounted on these plates. When reinforcements are placed inside the product manufactured, under certain circumstances these reinforcements are introduced in such a way that they rub against one and/or the other of the front and rear plates of the reservoir, or at least against their lower edges. To the extent that the height of the feed nozzles, the flow rate of the mixture, and the spacing between the front and rear plates of the reservoir, are set to correspond to the description in the aforementioned patent application U.S. Ser. No. 3,414, submerged streams cause stir lines which are visible on the surface, and these stir lines follow at least a trajectory from the front plate to the rear plate, and a return flow to the front plate, forming interlocking loops covering the whole surface of the reservoir, to the extent, that the front and rear plates are vibrated, deposits do not form which may entail massive setting, and the pouring device (henceforth called the pouring head) functions without assistance. However, if the pouring head is not adjusted precisely, splashing takes place and deposits may form, especially upon the rear plate, near the surface above the mixture, especially between the stir loops and in the corners of the reservoir. These deposits require occasional cleaning without nevertheless requiring the pouring to be stopped, the more frequently the worse the adjustment, for example, every two to three hours.
The pouring heads, even with the inconvenience of careful adjustment of the inconvenience of periodical cleaning of the rear plate, function satisfactorily up to a width of about sixty centimeters. But as the dimensions increase, the main problem becomes how to maintain the plates vibrating, especially the rear plate upon which the deposits principally form.