FR2582913A2 - Machine for continuously and uniformly coating products such as sweets or aperitif biscuits - Google Patents

Abstract

The subject of the invention is constituted by improvements to machines for continuously and uniformly coating products such as sweets or aperitif biscuits, which were the subject of Patent Application FR. 85/00412. A machine according to the invention comprises a trough 14 and two helical brushes 17g, 17d which consist of bristles implanted on two parallel shafts 16g, 16d. The two helices have a pitch of the same length and of reverse directions. The brush located on the left when looking in the direction of flow of the products has a right-hand pitch and it rotates in a counter-clockwise direction. The brush located on the right has a left-hand pitch and it rotates in a clockwise direction. The products to be coated form clusters 18 which are displaced between the two shafts. One application is the manufacture of confectionery articles (sweets, biscuits, dried fruit (nuts), cracked cereals).

Description

 The subject of the present invention is machines for continuously uniformly coating products such as sweets or aperitif cookies.

 The machines according to the present invention are improvements to the machines which were the subject of French patent application No. 85/00412.

 This application describes machines which comprise a rectilinear trough, at least one endless screw which is arranged in the bottom of this trough and which is composed of brush bristles implanted in a helix on a drive shaft, means for driving this shaft rotating at a slow speed of less than 100 revolutions / minute, means for pouring the products to be coated into the trough and means for injecting liquid and / or pulverulent products entering into the composition at one or more points of the trough of 11 coating.

 The objective of the present invention is to provide improved coating machines, which make it possible to increase the flow rate without modifying the speed of rotation, which make it possible to obtain a more uniform coating, which make it possible to build self-cleaning machines. and which make it possible to build coating machines capable of making popcorn type exploded cereals.

 According to a first improvement, a machine according to the invention comprises two parallel and substantially tangent worms, on which said brush weights are installed in the same pitch and in opposite directions and which are rotated in opposite directions. 'from one another, so that the said products to be coated form clusters located in the spaces which are between the drive shafts of the two screws and which are separated by the successive layers of bristles of the two brushes.

 Looking in the direction of circulation of the products, the helical brush located on the left has a step to the right and turns counterclockwise and the helical brush located on the right has a step to the left and turns in the clockwise, so that the bristles between the two drive shafts move up and down.

 According to a preferred embodiment, the bottom of the trough comprises two adjoining cylinder portions which each envelop a part of the periphery of an endless screw and which are connected to each other by a central edge which engages between the two endless screws.

 According to a second improvement, in the case of a machine comprising a single worm, the side wall of the trough, which is swept by the hair in the downward direction, has the shape of a portion of cylinder which extends the cylindrical bottom of said trough, so that said trough envelops more than half of the periphery of said worm.

 In the case of a machine comprising two worms, the two side walls of the trough have the shape of cylinder portions which extend the cylindrical bottom of the trough, so that each of said worms is surrounded on more half of its periphery and said side walls are Frolongég upwards by a substantially vertical wall.

 According to a third improvement, a machine according to the invention comprises one or two endless screws which each consist of brush bristles implanted on the same drive shaft according to two parallel helices, of the same pitch, offset by a half step.

 Advantageously, the trough of a machine according to the invention is equipped with means for spraying a cleaning liquid.

 According to a fourth improvement, a machine according to the invention intended for manufacturing exploded cereals comprises bristles of steel brush and means for heating part of the walls of the trough to a temperature between 1200C and 1500C.

 The present invention results in new and improved coating machines.

 Machines with two parallel helical brushes in opposite directions have the advantage that the products to be coated accumulate between the two brushes where a stirring effect is produced comparable to that of a kneading turbine without the products coming into contact with contact with the walls of the trough.

 Machines with one or two side walls which extend the cylindrical bottom of the trough above the horizontal plane in which the axis or axes of the worms are located have the advantage of eliminating the need to mount the shafts d driving the brushes on bearings and avoiding the phenomena of self-saturation of the machine in the case where the flow rate of product to be coated is greater than the transport capacity of the machine.

 Machines with one or two worms, which each consist of two helical brushes mounted on the same shaft and offset by half a step allow to increase the flow of the machine without increasing the speed of rotation of the worm end which must remain between 20 rpm and 100 rpm to prevent the products from being entrained in rotation around the shaft.

These machines make it possible to obtain a uniform coating despite the increase in throughput.

 The machines comprising means for heating the walls of the trough to a temperature between 1200C and 1500C make it possible to manufacture exploded cereals from cereals which have first been coated with oil in another section of the machine.

 The machines according to the invention, equipped with a spraying boom or any other means of dispensing a cleaning liquid, are self-cleaning machines which make it possible to move quickly from the manufacture of one product to another.

 The following description refers to the accompanying drawings which show, without any limitation being, examples of construction of machines according to the invention.

 Figure 1 is a partial top view of a machine according to the invention.

 Figure 2 is a section along Il-Il of Figure 1.

 Figure 3 is a section on III-IIL of an alternative embodiment.

 Figure 4 is a cross section of a second alternative embodiment of a machine according to the invention.

 Figure 5 is a top view of a third alternative embodiment of a machine according to the invention.

 Figure 6 is a cross section of a machine part according to the invention heated to make exploded cereals.

 Figures 1 and 2 show a partial top view and a cross section of a machine according to the invention intended to uniformly coat continuously confectionery products such as candies, savory or sweet biscuits, dried fruits, cereals intended to be exploded to obtain products of the popcorn type and, more generally, any product comprising solid cores which must be uniformly moistened and / or which must be uniformly covered with one or more layers of a pulverulent product, generally sugar, salt or cocoa.

 The machine according to Figures 1 and 2 has a straight trough 14 open upwards and at the front end.

 It has two worms 15d and 15g which are parallel to each other.

 Each endless screw comprises a rigid rectilinear drive shaft, respectively 16d and 16g and a helical screw 17d, 17g composed of bristles implanted helically on said shaft to form a helical brush. The hairs can be animal hair, plant stems, synthetic fibers or metallic threads.

 The two propellers have equal and opposite pitch. The arrow F represents the direction of movement of the products to be coated.

The solid cores of these products are poured into the trough near the upstream end thereof and they are moved in the direction of the arrow, forming clusters 18 in the form of a ball which rotate on themselves in at the same time as they advance, which has the effect that each core is coated uniformly by the liquids and / or the pulverulent solids which are poured into the trough.

 Figure 2 shows a cross section oriented downstream, that is to say looking in the direction of movement of the products.

 We see on this section that the propeller 15g, located on the left of the figure, has a step to the right and is driven in rotation in the opposite direction to the pitch, that is to say in the opposite direction to that of the needles of a watch.

 The propeller 15d located on the right has a step to the left and it is rotated clockwise.

 The two propellers are arranged substantially in phase opposition to each other and they are substantially tangent to each other in the median plane between them.

 We see in Figure 2 that the bristles of the two brushes located between the two drive shafts 16d and 16g, in the part where the two brushes are tangent, move from bottom to top and it is in this part that the products to be coated which are lifted by the bristles of the brushes and which fall down when they escape from them accumulate to form a cluster 18 which is driven in a rotational movement on itself. As can be seen in FIG. 1, there is formed in the space delimited by the two drive shafts 16g and 16d a series of clusters 18 each located downstream of a point of tangency of the two brushes and each of these amas fulfills a miniturbine function which continuously mixes the products to be coated from one end to the other of the trough 14 where they are discharged.

Advantageously, as can be seen in FIG. 2, the bottom of the trough 14 is composed of two adjoining cylinder portions 19g and 19d which each envelop part of the periphery of a screw up to the level of the plane PP 'in which are located the axes of the shafts 16g and 16d and which extend above this plane PP 'by walls 20d, 20g vertical or inclined;
The two half-cylinders 19g and 19d are symmetrical with respect to the median longitudinal plane and they overlap therein forming a central edge 21 which engages between the two propellers while remaining tangent thereto.

Figure 3 shows a cross section along
II-II of an alternative embodiment.

 The homologous parts are represented by the same references in Figures 2 and 3. The propellers are identical.

 The two side walls 20d and 20g of the trough situated above the plane PP 'have the shape of cylinder portions which extend the cylinder portions 19d and 19g, so that each worm is wrapped over more than half of its periphery and advantageously three quarters of its periphery as shown in Figure 3. This particular shape of the side walls of the trough has the advantage that the two brushes are held in place in the bottom of the trough by the side walls without the need to mount the shafts 16g and 16d in bearings to prevent the brushes from lifting. This eliminates the bearings which slow down the movement of the products to be coated and which disturb the regularity of the movement of mixing of the product masses.

On the other hand, in case of saturation of the machine, the products to be coated can rise in the vertical part of the trough
located between the vertical walls or slightly inclined on the vertical .22d, 22g which extend above the brushes.

 The products then escape the action of the brushes and we thus obtain a self-regulation of the saturation phenomenon.

 The embodiments according to Figures 1 to 3 which have two parallel brushes have the advantage, compared to machines with a single brush, that the heaps 18 of products to be coated are located between the two brushes, without any contact with the walls of the trough. This avoids friction against the walls which can damage certain fragile products and which can lead to coating of the products which is not uniform.

 In addition, the double helix machines make it possible to increase the flow rate of the machine and the particle size of the products because the space between the two brushes in which the clusters of products 18 are formed and maintained is larger than the space between the rising bristles and a side wall of the trough where the products accumulate in the case of a machine with a single helical brush.

 FIG. 4 represents a cross section looking downstream, that is to say in the direction of flow of the products, of a machine according to the invention comprising a single helical brush composed of a drive shaft 24 on which is implanted a helical brush formed of bristles 25.

 Figure 4 corresponds to a propeller having a left pitch which is rotated in a clockwise direction.

 The products to be coated accumulate by forming a heap 26 along the side wall of the trough 23 which is swept by the bristles of the brush in the upward direction. The gauge 23 has a bottom 28 in the form of a half-cylinder which follows the outline of the helical brush.

The side wall 29 of the trough situated on the side which is swept upwards is connected tangentially to the cylindrical bottom 28. The wall 30 of the trough which is swept by the helical brush in the downward direction has the shape of a portion of cylinder which extends the cylindrical bottom 28 so that the trough envelops the helical brush over more than half of its periphery. Advantageously, the cylindrical wall 30- extends up to the vertical of the axis of the shaft 24, so that the trough envelops three quarters of the periphery of the brush.

 The cylindrical wall 30 is extended upwards by a flat wall 31 which can be vertical or slightly oblique and which defines with the wall 29 a chute 32 surmounting the brush. This arrangement has, in the case of a machine with a single brush, the same advantages as the embodiment according to FIG. 3.

 The helical brush is held in the bottom of the trough by the cylindrical wall 30 without the need to mount the shaft 24 in bearings. In addition, in the event of saturation, the excess products go up into the chute 32 where they escape the action of the brush and the wall 30 prevents them from being rotated around the shaft 24 and qu 'They do not join the cluster which precedes them.

 FIG. 4 shows a cleaning device which can be applied to all the machines according to the invention.

 This device comprises one or more ramps 33, 34 which distribute a cleaning liquid, for example hot water, all along the trough. These ramps can be perforated tubes or tubes fitted with sprayers which project jets of sprayed liquid into the trough.

 The machines according to the invention, in particular those which are used to manufacture products coated with sugar, tend to become dirty and it is necessary to clean them after each work station.

 For this, it suffices to start the ramps 33, 34 liquid dispensers. The bristles of the brush which rub against the walls then act as a cleaning brush and the dirt is drawn towards the exit of the trough by the heli-cotidal brush which at the same time acts as a conveyor. One thus obtains, with inexpensive means, a self-cleaning coating machine making it possible to carry out a thorough cleaning of the machine after each work station where between the manufacture of different products.

 FIG. 5 represents a partial top view of an alternative embodiment of a machine according to the invention.

 FIG. 5 represents an example of a machine comprising a trough 35 composed of a bottom in the form of a half-cylinder extended by two vertical side walls.

 It is specified that the trough could also have the shape shown in FIG. 4.

 The coating machines according to the invention rotate at very slow speeds of between 20 rpm and 1Oot / min. As a result, their throughput is very reduced. To increase the flow, the idea that naturally comes to mind is to increase the pitch, so that the axial speed of movement of the products increases.

 But by increasing the pitch, we end up with an increased distance between two steps which risks containing too large clusters of product, which turn badly on themselves, so that the coating is no longer uniform.

 In addition, if the clumps of products are very large, they exert a higher pressure against the bristles of the helical brush and as these are flexible, they tend to bend and let escape products which join the 'cluster located upstream.

 FIG. 5 represents an alternative embodiment which makes it possible to increase the flow rate of the machine, without increasing the speed of rotation and without increasing the volume of the individual piles 36 of products to be coated.

 According to this variant, the machine comprises a rigid drive shaft 37 and two helical brushes 38 and 39, of the same pitch and of the same direction which are interlaced, that is to say that they are axially offset by a half -not. Thus, each time the tree turns a revolution, the machine delivers two clusters 36 but these are separated by a layer of bristles as they progress along the trough.

 This gives a better turbine effect. Clusters 36 which are smaller are better stirred and the coating is more uniform.

 For the same flow rate of the machine, the quantity of products in each cluster 36 is divided by two and each cluster therefore exerts a lower pressure on the brush. It is thus possible to obtain a higher flow rate while maintaining a low speed of rotation and a uniform coating of the products.

 It is specified that the embodiment according to FIG. 5 can also be applied to a machine according to FIG. 1 which would then comprise two shafts each carrying two heli cotidal brushes intersecting.

 FIG. 6 shows a cross section of an alternative embodiment of a part of a machine according to the invention for making popcorn-type exploded cereals.

 It will be recalled that the manufacture of these cereals comprises a step of coating in oil, possibly steps of coating in products such as honey or sugar and a step of bursting in contact with a wall heated to a temperature between 1200 and 1500.

 Figure 6 shows a section of the part of the machine in which the burst takes place, this part following a part where the coating took place.

 FIG. 6 represents an example of a machine comprising a trough 40 similar to that of FIG. 4 and a single helical helix.

 It should be noted that this example is not limiting. The embodiment according to FIG. 6 can also comprise a trough having two flat transverse walls or a machine according to FIGS. 1 to 3 comprising two parallel endless screws or a machine according to FIG. 5 comprising two crossed helical brushes.

 The helical brush of the machine according to Figure 6 is composed of bristles 41 which are strands of stainless steel which are implanted on a metal drive shaft 42 along a helix having a left pitch.

 The figure is a view looking in the direction of flow of the products and the shaft 42 is driven in a clockwise direction.

 The gauge 40 has a double wall 43a, 43b which delimits an intermediate space 44 in which a heat transfer fluid is circulated, for example dry steam or an oil at a temperature of the order of 1500, so that the cereals 45 burst on contact with the hot wall. The mixing of the products due to the action of the brush causes all the cereals to come into contact with the hot wall and burst. Advantageously, the external wall 43a carries a heat-insulating coating 46.

 Alternatively, instead of using a double-walled trough in which a heat-transfer fluid circulates, a metallic trough can be used which is heated locally by burner flames or by electric resistors-placed inside a box insulated.

 FIG. 4 shows an exemplary embodiment in which the vertical wall 29, which is swept by the bristles of the brush in the upward direction and against which the products accumulate 26, comprises a rib 47 projecting from the inside of chute 32.

 This rib is disposed substantially at the level of the upper generatrix of said helical brush 25.

 It has been noted that the products to be coated which rub against the wall 29 tend to stick against it and continue to rise along the latter under the pressure of new products. A strip of products is thus formed in the long run stuck to the wall located above the area which is swept by the brush. The rib 47 hermits the formation of this strip of products immobilized against the wall.

 The products located below the rib 47 are constantly renewed by new products pushed by the brush.

 With regard to the embodiment according to FIGS. 1 and 2, it has been seen that the clusters of products 18 are formed between the two helical brushes, without being in contact with the side walls of the trough 14. This prevents products do not stick against the wall and progress downstream while remaining stuck to the latter, resulting in poor coating.

Claims (10)

 1. Machine according to claim 2 of the main application, characterized in that it comprises two endless screws (15g, 15d) parallel and substantially tangent, on which said brush bristles are installed along helices (17g, 17d), in the same way and in the opposite direction and which are rotated in opposite directions to one another, so that the said products to be coated form clusters (18) located in the spaces which are between the shafts d drive (16g, 16d) of the two screws and which are separated by the successive layers of bristles of the two brushes.  2. Machine according to claim 1, characterized in that, looking in the direction of flow of the products, the helical brush located on the left (17g) has a step to the right rotates counterclockwise and the helical brush on the right (17g) has a step to the left and rotates clockwise, so that the bristles between the two drive shafts (16g, 16d) move from bottom to top .  3. Machine according to any one of claims 1 and 2, characterized in that the bottom of said trough comprises two adjoining cylinder portions (19g, 19d) which each surround part of the periphery of a worm (17g , 17d) and which are connected to one another by a central edge (21) which engages between the two worms.  4. Machine according to claim 2 of the main application, comprising a single worm, characterized in that the side wall (30) of said trough (23), which is swept by the bristles in the downward direction has the form d 'a portion of cylinder which extends the cylindrical bottom (28) of said trough, so that said trough envelops more than half of the periphery of said worm.  5. Machine according to any one of claims 1 to 3, characterized in that the two side walls of said trough (14) have the shape of cylinder portions (20d, 20g) which extend the cylindrical bottom of the trough, so that each of said endless screw (17g, 17d) is surrounded over more than half of its periphery and said side walls are extended upwards by a substantially vertical wall (22d, 22g).  6. Machine according to claim 2 of the main application, characterized in that it comprises one or two endless screws which each consist of brush bristles implanted on the same drive shaft along two propellers (38, 39) parallel, similarly, offset by half a step.  7. Machine according to claim 2 of the main application, characterized in that the trough is equipped with spraying means (33, 34) of a cleaning liquid.  8. Machine according to claim 2 of the main application, intended for manufacturing exploded cereals, characterized in that said brush bristles are steel bristles and it comprises means for heating part of the walls of said trough to a temperature comprised between 1200 and 1500.  9. Machine according to claim 8, characterized in that the trough (40) has two walls (43a, 43b) which delimit an intermediate volume (44) and means for circulating in this volume a heat transfer fluid and the external wall has a thermal insulating coating (46).  10. Machine according to claim 2 of the main application comprising a single worm, characterized in that the side wall (29) of said trough (23), which is swept up by the bristles of the brush has a rib ( 47) in relief towards the inside of the trough which is situated substantially at the level of the upper generatrix of said helical brush (41).