Pellet press

#The invention relates to an installation comprising a press-through surface containing openings and pressure means for pressing goods through the openings in the press-through surface. This known installation is used for kneading or rubbing pulverulent products in order to produce a coherent end product therefrom. For such particular purpose, so called pallet mills are known from e.g. U.S. Pat. Nos. 2,958,900 or 3,251,316, which are incorporated herein by reference. For example, the production of animal feed from meal or the production of chocolate can be considered. During processing using the known installation the pulverulent product is rendered plastic and freed from air, while the temperature of the product rises, as a result of which decomposition of, for example, proteins and/or starches occurs to provide the end product with the desired shape and hardness and to change the composition of the end product, such that in, for example, the processing of meals the nutritional value increases. Frequently, steam is supplied in order to improve the end result.

#As a consequence of the increasing use of raw materials of, for example, a poorer quality or of a different type, increasingly more stringent demands are being made in respect of the kneading or rubbing treatment, especially with regard to the pressure under which the raw material is pressed through the openings in the press-through surface. At present this is solved by allowing the raw material successively to undergo various kneading operations, for example by feeding the raw material successively through various installations of the known type.

#The object of the invention is to provide an improved installation of the abovementioned type with which the abovementioned problem is solved.

#The invention will be explained in more detail below with the aid of non-limiting illustrative embodiment with reference to the drawings, In the latter:

#FIG. 1 shows, diagrammatically, a cross-sectional view of an installation according to the invention;

#FIG. 2 shows a detail of the installation of FIG. 1, in cross-section;

#With reference to FIGS. 1-3, the installation 1 comprises a drum-shaped feed sleeve 2, which has connection points 3, 4 for supplying steam and other additives such as soya oil, molasses or water. The sleeve 2 has an intake 7 for feeding in pulverulent raw material. A rotatable conveyor shaft 5 is fitted inside the drum 2. Said conveyor shaft is provided with conveyor propeller blades 6. If appropriate, the blades 6 can be replaced by conveyor paddles (not shown). The conveyor shaft 5 is driven by motor 8. By this means the raw material is conveyed from the drum-shaped feed sleeve 2 to the rubbing chamber 9, through the openings between the spokes 11 for suspension of the conveyor shaft 5.

#The rubbing chamber 9 has a drum wall 12 containing closable openings 13 according to the invention. With the aid of rubbing shoes 14 (only one shown in FIGS. 1 and 2), the product introduced into the installation 1 is pressed through the drum wall 12 to the outside. FIG. 3 shows two rubbing shoes 14 and an alternative in the form of a rubbing roller 15 in the position where the third rubbing shoe is normally located. If rubbing shoes 14 are used these are rigid, so that they always assume the same position with respect to the drum wall. Rubbing rollers rotating about their axis can be used. Said rubbing shoes 14 or rubbing rollers 15 are also driven by the conveyor shaft 5 in the direction of the arrow A (FIG. 3) and thus move over the drum surface, forming a friction gap 16 with the drum surface, which gap widens in the direction of movement. Alternatively, the rubbing shoes 14 could be driven by an additional shaft, which runs through the conveyor shaft 5. This makes it possible to individually drive the shoes 14 and the propellors 6. The rubbing shoes 14 or rubbing rollers 15 are fixed in a known manner using an adjustable eccentric (not shown), so that their distance from the drum wall is adjustable.

#The drum wall 12 comprises four rings 17, the edges of the rings which face one another being bevelled. The rings 17 are resiliently driven towards one another by three assemblies (one of which is shown in FIG. 2) comprising a through bolt 18 with a spring 19, as a result of which the gap-shaped openings 13 between the rings 17 are kept pressed closed when the installation 1 is not in operation.