ROLLING APPARATUS FOR FORMING A CONTINUOUS STRIP OF DOUGH OR A SIMILAR PLASTIC MATERIAL

Abstract: Rolling apparatus comprising two rollers (2) and (3) (Figure 1) or (22) (Figure 2) disposed horizontally adjacent to each other, one roller (2) of which has rough surface. Above the gap (5) between these rollers is a stock holder (6) with an open bottom end. Dough (7) placed in the holder (6) falls on to the rollers and is conveyed by the roller (2) through the gap (5), so that a strip of dough leaves the gap (5). Disposed below the gap (5) is a third roller (4) which is parallel to the two top rollers. Rotatably mounted on the periphery of the roller (4) are a number of rolls (12). The strip of dough goes from the gap (5) through a gap (13) between the bottom roller (4) and the top roller (3) (Figure 1) or (22) (Figure 2), which is preferably a roller of the same type as the bottom roller (4), opposite the top roller (2) with rough surface, so that the rolls make the strip of dough thinner, while retaining its structure.

Description: The invention relates to an apparatus for the continuous rolling of dough and similar plastic materials to a continuous strip, comprising a dough stock holder, and three rollers having horizontal and parallel axes of rotation and being arranged beneath the holder with an inlet gap beneath said holder between two upper rollers for receiving said dough from said holder and an outlet gap between an upper roller and a lower roller for providing said strip, and the rollers being coupled to a drive mechanism for rotating the rollers in directons corresponding to a downward conveyance of the dough through said gaps, with one top roller having an uneven surface for conveying the dough out of the holder. An apparatus of this type is known from GB-A-2 031 328. With this prior art apparatus the three rolls have side flanges for providing a chamber between the rolls in which dough received therein from the hopper through the inlet gap is compressed and supplied through the outlet gap. According to said reference it is highly desirable to provide these rolls with a thin surface coating of antifriction material for allowing to slip relative to the dough when pressures approach the level at which shaft breakage would be likely to take place. It is important that during the processing of yeast dough products the number of carbon dioxide cells developed in the dough through the working of the yeast should increase in a second proving period. In the known apparatus, the pressing of the dough between the rollers and into the pressure chamber for the purpose of obtaining a continuous strip less than about 15 mm thick will break the structure of the dough, and the walls of the gas cells developed in a previous rising period are broken. The continuous strip thus obtained consists of a so-called dead dough, in which the number of gas cells increases little, if at all, during a second proving period, while the dough does rise again. After further processing of the strip of dough and baking of it, a bread product with large gas cells is obtained, so that the bread product can retain relatively little moisture and soon becomes stale. Therefore, since with the prior art apparatus high pressures occur in the chamber between the three rolls, dough products, prior and after baking, with a poor quality are obtained with the prior art apparatus. The object of the invention is to eliminate the disadvantages of the prior art apparatus. This object is achieved for the apparatus mentioned in the preamble according to the invention by that the lower roller is arranged substantially centred below the inlet gap, the lower roller consists on the periphery thereof of a number of rotatably mounted rolls having horizontal axes of rotation parallel to the axis of the lower roller and the peripheral speed of the lower roller is greater than the peripheral speed of an upper roller having a continuous peripheral surface. The width of the inlet gap can be selected such that it is larger with respect to the thickness of the continuous strip obtained with the apparatus, so that the dough is not compressed much between the upper rollers. The strip of dough emerging from the inlet gap between the upper rollers is conveyed downwardly against an upper roller. Since the peripheral speed of the lower roller is greater than the peripheral speed of an upper roller with a continuous surface and since the rolls on the periphery of the lower roller are rotatably mounted, the latter rolls will push a wall of dough in front of them during which the layer of dough from the inlet gap is reduced in a manner which is similar to that where a thick slab of dough is reduced by hand with a rolling pin. The structure of the dough is retained in the process, so that during a second proving period the number of carbon dioxide cells developed through the working of the yeast increases appreciably, with the dimensions of the cells being relatively small. The finer texture of the dough thus obtained results in that a product baked from this dough will be able to retain moisture for a relatively long time, so that the baked product remains soft and keeps longer. With the apparatus according to the invention, it is possible to obtain very good quality strips of dough which are only 5 mm thick. In a preferred embodiment of the apparatus according to the invention one upper roller consists of a number of rotatably mounted rolls having horizontal axes of rotation parallel to the axis of said one upper roller. This practically rules out completely the occurrence of high pressures between the rollers. As a result a good structure of the dough will be better retained. It is pointed out that the proposal for the apparatus according to the invention was found to surprisingly produce a very good result. Contrary to what was initially feared, the dough coming out of the gap between the two top rollers did not clog the space between the rollers, which would have resulted in that the structure of the dough would have been seriously damaged, just as in the pressure chamber in the prior art apparatus. The invention is explained with reference to the figures. In the figures: Figure 1 shows a first embodiment of the apparatus according to the invention; and Figure 2 shows a second embodiment of the apparatus according to the invention. The apparatus shown in Figure 1 comprises a frame 1 and three horizontal rollers 2, 3, 4 rotatably mounted parallel to each other in flanges of the frame 1. The two top rollers 2, 3 with approximately equal diameter, are disposed adjacent to each other with a gap 5 between them. Disposed above the region of the gap 5 is a stock holder 6 for a quantity of dough 7 or another similar plastic material. The upright walls of the stock holder 6, which run parallel to the central axes of the roller 2, 3, are slanted at an angle of about 1 degree, so that the distance between the walls increases downwards. The rollers 2, 3, 4 are driven rotatably by means of drive mechanisms (not shown) in the directions indicated by the arrows 8, 9 and 10 respectively. Formed in the periphery of the top roller 2 are grooves 11 which run parallel to the central axis of the roller 2, and which give a good grip on the dough 7 present in the holder 6 for conveying the dough out of the holder 6 downwards through the gap 5. The rollers 2 and 3 act here as pre-shaping devices. The roller 4 is disposed approximately centred below the gap 5 and is provided on its periphery with a number of rolls which run parallel to the central axis of the roller 4 and are rotatably mounted in flanges of the roller 4. The dough leaving the region of the gap 5 between the top rollers 2, 3 is conveyed over the rolls 12 of the roller 4 and thereby passes a gap 13 formed between the top roller 3 and the roller 4. Since the rolls 12 come into contact with the dough in the region of the gap 13, the rolls 12 therein will roll over the dough in the direction indicated by the arrow 14. The peripheral speed of the roller 4 is selected to be about ten times the peripheral speeds of the top rollers 2 and 3. This means that the rolls 12 will always push part of the dough ahead of them in the form of a wall, the height of the wall decreasing as the rolls 12 go closer to the gap 13. In this way the dough is flattened, and one obtains a continuous strip of dough in which the cell structure of the carbon dioxide gas developed by the yeasts is retained. The number of cells can thereby increase substantially during a second providing period, so that a fine texture is obtained, as a result of which a product formed from this dough and baked can retain moisture longer, and remains soft and keeps longer. Disposed on the other side of the roller 4, in the centre region thereof parallel to the roller 4 is an oblong flour sprinkler 16. The flour sprinkler 16 comprises a container 17 for a quantity of flour. The dimensions of the horizontal cross section of the container 17 decrease downwards. The container 17 has on the underside an opening, the vertical dimension of which can be set by means of a slide 18. Disposed in the opening is an oblong brush 19, which projects so far outwards that the end part thereof is caused to vibrate by the passing rolls 12. In the process, flour from the container 17 will be deposited on the rolls 12, which prevents the dough from sticking to the rolls 12. In addition, flour will fall onto a conveyor belt (which is not shown) which discharges the strip 20 of dough coming out of the rolling apparatus. This prevents the strip 20 of dough from sticking to the conveyor belt. The smooth surfaces of the roller 3, the holder 6 and the rolls 12 with which the dough comes into contact are preferably provided with a coating with low coefficient of friction, for example Teflon (trade mark). The roller 4 is preferably movable in the direction indicated by the double arrow 21, so that a continuous strip 20 with adjustable thickness can be obtained. In the second embodiment of the apparatus according to the invention shown in Figure 2, the top roller 3 with smooth surface of Figure 1 is replaced by a roller 22 with roller 23 running parallel to the central axes of the rollers 2, 4, 22 said rolls 23 being rotatably mounted along the periphery of the roller 22. The roller is driven in the direction of the arrow 9, so that the rolls 23 turn in the direction of the arrow 24. Although this is not indicated in the figure, the position of the roller 22 is preferably adjustable relative to the other rollers 2,4. In the apparatus according to Figure 2 practically any occurence of a pressure chamber in which the walls of the gas cells present in the dough would be undesirably broken is prevented. With the apparatus according to Figure 2, an even thinner dough strip of good quality can therefore be obtained. The rolls 12, 23 of the rollers 4, 22 could possibly be driven by means of a friction element acting upon the rolls, such as a brake shoe.

Claims: Apparatus for the continuous rolling of dough (7) and similar plastic materials to a continuous strip (20), comprising a dough stock holder (6), and three rollers (2,3,4; 2, 4,22) having horizontal and parallel axes of rotation and being arranged beneath the holder (6) with an inlet gap (5) beneath said holder (6) between two upper rollers ( 2,3,4; 2,4,22) for receiving said dough (7) from said holder (6) and an outlet gap (13) between an upper roller (3;22) and a lower roller (4) for providing said strip (20), and the rollers (2,3,4; 2,4,22) being coupled to a drive mechanism for rotating the rollers (2,3,4; 2,4,22) in directons corresponding to a downward conveyance of the dough through said gaps (5,13), with one top roller (2) having an uneven surface for conveying the dough out of the holder (6), characterized in that the lower roller (4) is arranged substantially centred below the inlet gap (5), the lower roller (4) consists on the periphery thereof of a number of rotatably mounted rolls (12) having horizontal axes of rotation parallel to the axis of the lower roller (4) and the peripheral speed of the lower roller (4) is greater than the peripheral speed of an upper roller (2,3; 2) having a continuous peripheral surface. Apparatus according to claim 1, characterized in that the peripheral speed of the lower roller (4) is about five to fifteen times the peripheral speed of the upper roller (2,3; 2) having a continuous peripheral surface. Apparatus according to claim 1, characterized in that the position of the lower roller (4) is adjustable relative to the upper rollers (2,3; 2,22) by means of setting elements. Apparatus according to claim 1, characterized in that one upper roller (22) consists of a number of rotatably mounted rolls (23) having horizontal axes of rotation parallel to the axis of said one upper roller (22). Apparatus according to claim 1, wherein the holder (6) has a pair of opposite upright walls running parallel to said axes of rotation, characterized in that said walls diverge downwardly. Apparatus according to claim 5, characterized in that a divergency angle of said walls is about 1 degree. Apparatus according to claim 1, characterized in that in a region about halfway up the lower roller (4) there is arranged a flour sprinkler (16) opposite the lower roller (4) for sprinkling flour on the rolls (12) of the lower roller (4). Apparatus according to claim 7, characterized in that the flour sprinkler (16) comprises a flour container (17) and a brush (19), in which an outer longitudinal end part of the brush (19) runs within the outer periphery of the lower roller (4) bounded by the rolls (12) said outer part receiving flour from the container (17) through contact by the rolls 612) and releasing the flour to the rolls (12).

Inventors: RIJKAART, CORNELIS
Applicants: MACHINEFABRIEK C. RIJKAART B.V.
Application year: 1987
Main classification: A21C3
IPC codes: A21C3