Abstract:
A device is provided for continuously feeding chocolate ingredients, such as flakes, to a continuous conche having an adhesion prevention means to prevent adhesion of the ingredients to surfaces of the device exposed to the ingredients. In a process for continuously feeding chocolate ingredients, such as flakes, to a continuous conche, adhesion of the ingredients to surfaces exposed to the ingredients, is continuously prevented.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
       [0001]    This application claims foreign priority under 35 U.S.C. §119 to European Patent Application No. 10151772.0, filed Jan. 27, 2010, which is hereby incorporated herein by reference in its entirety. 
       FIELD 
       [0002]    The disclosure relates to a system and a process for producing a chocolate mass. 
       BACKGROUND 
       [0003]    In the field of chocolate making, conches are known which are normally operated in a batch-wise manner. In other words, the conche is filled with the ingredients, is operated for a certain time and as a result of the process, chocolate mass can be taken from the conche after finishing the operation. 
         [0004]    Continuous conches having one or more screws have been proposed, for example, by U.S. Pat. No. 4,679,498. 
       SUMMARY 
       [0005]    The disclosure relates to a device and a process for continuously feeding chocolate ingredients to a continuous conche. 
         [0006]    The disclosure provides a device and process for an efficient production of chocolate mass by a continuous conche. The device solving these and other problems is described in claim  1 , and the related process is detailed in claim  15 . Specific embodiments are given in the dependent claims. The system having a device as described herein and the process for producing a chocolate mass incorporating the process described herein are described in claims  14  and  22 , respectively. 
         [0007]    The disclosure is to some extent based on the finding, but not limited thereto, that a continuous flow of, for example, 1500-2500 kg/h of the ingredients for forming a chocolate mass, such as the so-called flakes, is essential for allowing efficient and reliable production of chocolate mass in a continuous conche. The mentioned flakes mainly consist of sugar, cocoa butter, cocoa liquor and cocoa powder which have been ground and refined as is well known to those skilled in the art. Further, particularly for the manufacture of milk chocolate, the cocoa powder may partially or fully be replaced by milk powder which may comprise sweet whey powder and milk fat. Further, for the manufacture of white. chocolate, cocoa liquor may be omitted. Usually, the described flakes are warm. 
         [0008]    It is noted that the features described herein are applicable to any chocolate or chocolate-like material which may be called chocolate under local laws. In particular, chocolate-like materials may comprise any food materials derived from the cocoa bean and any confectionery material having fat. 
         [0009]    As regards the continuous conche, as described herein, this conche may have one or more shafts having a helical structure at their periphery, such as a spindle or a screw. One or more spindles may be intermeshing with other spindles, and the continuous conche may be provided as an extruder, particularly a planetary roller extruder. Such an extruder may, for example, be manufactured by ENTEX Rust &amp; Mitschke GmbH, Heinrichstrasse 67, 44805 Bochum, Germany. For the mentioned types of continuous conches, it has been found that they advantageously provide the required (high) heat transfer to the ingredients, the necessary mixing and shearing thereof, in order to produce a homogeneous chocolate mass in a continuous, highly efficient process. In particular, the conching time, i.e. the time which the ingredients spend in the conche before they have turned to chocolate mass, can be reduced from several hours to only a few minutes. Further, the space required for the above-described continuous conche is significantly less than that of traditional (batch) conches, so that efficiency of the process is improved also in this regard. This particularly applies when the amount of chocolate mass obtained is taken into account. Traditional conches may produce between 5 and 12 tons of chocolate mass per day, whereas the above-described continuous conches allow the production of 2 to 3 tons per hour, and even more depending on their size. 
         [0010]    As indicated above, the feeding of the ingredients to a continuous conche leads to specific requirements. In particular, it was found that reliability of the described process can be significantly improved if the ingredients are continuously supplied, e.g. by being prevented from adhering to the surfaces of the device exposed to the ingredients. As will be detailed below, there are several occasions and locations where the ingredients tend to adhere or stick to the surfaces of the device. Depending on the specific situation and process parameters, the locations require different measures for preventing the ingredients from adhering. In particular, it was found that there are situations in which the application of adhesion preventions means at one particular location is sufficient for ensuring a steady feeding of ingredients. Moreover, several measures to prevent adhesion can be combined with each other. 
         [0011]    In particular, the device described herein may have one or more conveyors, one or more buffer tanks, one or more feeding devices, such as pistons or screws including a casing and one or more hoppers, substantially provided in a screw casing in order to feed the ingredients to the feeding screw, for example, by a conveyor. One or more of the conveyors may be provided by Bühler AG, 9240 Uzwil, Switzerland and/or BSA Schneider Anlagentechnik GmbH, Grüner Winkel 7-9, 52070 Aachen, Germany and/or Petzholdt-Heidenauer Maschinen-und Anlagenbau International GmbH, Niedersedlitzer Straβe 41, 01239 Dresden, Germany. One or more buffer tanks may have a size of about 800 litres and may be manufactured by Reimelt Foodtechnologie GmbH, Messenhäuser Straβe 37-45, 63322 Rödermark, Germany. Further, the lower part of the buffer tank may have an inclination angle of about 40°. This has proven to provide a reliable flow of the ingredients. This is further supported if the inner surfaces of at least one buffer tank are at least partially Teflon coated or provided with a surface which assists in preventing adhesion of the ingredient to the surfaces of the buffer tank in any other manner. One or more feeding screws may have a total length of about 0.4 m, with about 0.3 m being provided with a helical, screw-type structure to provide a conveying or feeding effect, and the remainder of the screw being provided, for example, with a type of pulley for driving same. The inner diameter of one or more feeding screws may be about 10.5 cm and the outer diameter may be about 15.5 cm. Further, the pitch length may be about 15 cm. Finally, one or more feeding screws may be manufactured by Entex, mentioned above with regard to the extruder. This also applies to one or more hoppers which may further have at least one lower opening which is substantially rectangular with a length of about 17 cm and a width of about 10 cm. The upper opening may a length of about 29 cm and a width of about 22 cm. Further, the height of a conical part of the hopper may be about 24 cm, and the height of a lower part having substantially vertical walls may be about 9 cm. It is noted that any of these specific dimensions mentioned above or below are, as the skilled person will appreciate, dependent on the type and/or dimensions of the surrounding components. 
         [0012]    As detailed below, the adhesion prevention means described herein, may be provided at one or more of the above-mentioned components. 
         [0013]    For example, it was found that the ingredients tend to stick and even build so-called bridges at the interface of a feeding screw, feeding the ingredients to the continuous conche, and one or more openings where the ingredients are fed to the feeding screw. For example, at this interface at least one hopper can be provided into which the ingredients are deposited by at least one conveyor. In order to prevent the ingredients from adhering to the walls of the hopper and/or the casing of the screw, at least one flexible wall is provided in the hopper and/or the casing. The at least one flexible wall representing a relatively simple and efficient mechanical measure, may be moved and/or deformed frequently to destroy any “bridges” or buildups of ingredients which have the potential of impairing the continuous feeding of ingredients to the continuous conche. The flexible wall may, for example, be made of polyurethane (PU) or any other material which is deformable under the conditions which are present in the surroundings of the devices described herein. Further, one or more level sensors may be provided in the above-mentioned hopper in order to provide an automatic monitoring of the filling situation at the hopper and control the process appropriately based on this information. 
         [0014]    In the experiments conducted, very good results were experienced, particularly with at least one wall moving and/or inflating means. These wall moving means may, for example, be provided as one or more pneumatically operated pistons, for example, manufactured by Festo AG &amp; Co. KG, Ruiter Str. 82, 73734 Esslingen-Birkheim, Germany. In other words, one or more wall or section thereof may be provided as a flexible wall by being movable with respect to at least one adjacent wall. This provides the above described advantageous effect of destroying bridges or buildups. This also applies to the inflating means. In this case, one or more walls are provided as flexible walls and part of an inflatable area. Thus, this area or space may be inflated frequently in order to move and/or deform the flexible wall, so that, also in this case, any buildups of chocolate ingredients are caused to fall to an area where they can be conveyed further, e.g. by the feeding screw. 
         [0015]    The above measures may or may not be combined with at least one surface exposed to the ingredients which is not adhesive to cold or warm chocolate ingredients. Thus, any surfaces, in particular also those of a conveyor and/or a feeding screw are provided to prevent adhesion of ingredients. 
         [0016]    As experiments have shown, this may, for example, be achieved by providing the exposed surfaces with a low surface roughness, for example about Ra=1.0 μm or less. 
         [0017]    Further, good results have been achieved with surfaces which may be ceramic surfaces and/or lacquered, e.g. with hybrid lacquer which may for example be supplied by Zion Zentrum für Oberflächenveredelung &amp; Nanotechnologie, Karl Arnold Str. 5, 47877 Willich, Germany or European Surfaces Technologies GmbH, Dr. Alfred Herrhausen Allee 16, 47228 Duisburg, Germany under the trademark “HBL Hybrid Lack” and/or teflonized surfaces and/or electroplated, for, example with chrome, surfaces. In other words, one or more surfaces, particularly of one or more screws may be coated with PTFE. Teflon coating has also proven efficient in connection with the inner surfaces of the buffer tank described below. Further, as regards, for example, a feeding screw, sintered stainless steel material has proven beneficial as a base material of the feeding screw. Also, one or more surfaces may be provided with a coating and/or a surface based on nanotechnology in order to achieve the adhesion prevention effect. 
         [0018]    It was also found that particular design measures of the equipment involved are beneficial for preventing the adhesion of chocolate ingredients. For example, at least one feeding screw may have a ratio of its pitch length (L) to its outer diameter (D) of about 3 to about 1. In this range, and especially with a L/D ratio of about 1, good results have been obtained with regard to the prevention of adhesion and ensuring continuous feeding of the ingredients. 
         [0019]    Moreover, the device may have at least one buffer tank in order to cope with any adhesion of chocolate ingredients which can only be removed from time to time. In other words, it may be beneficial to buffer the ingredients in order to harmonize a flow of ingredients to the buffer which might be interrupted, possibly because of adhesion, from time to time. Further, the chocolate ingredients, in particular chocolate flakes, are typically supplied from one or more refiners, which do not always guarantee a constant continuous flow of ingredients. Consequently, this flow can be harmonized by one or more buffer tanks. Further, the provision of one or more buffer tanks may aid in securing a continuous flow of chocolate ingredients as follows. It has been found quite unexpectedly that adhesion of chocolate ingredients occurs when the flow of ingredients is interrupted. In other words, a continuous flow of ingredients may prevent the ingredients from adhering to any of the exposed surfaces, whereas whenever there is an interruption in the flow of ingredients, i.e. when the ingredients stay at a particular place contacting the exposed surface for a somewhat longer time period, adhering and sticking occurs. Since a buffer may compensate any discontinuities in the flow, a steady flow of the ingredients from the buffer can be achieved, and adhesion of ingredients downstream of the buffer can advantageously be minimized. 
         [0020]    In order to prevent adhesion in the buffer, particularly in the buffer tank itself, it has proven efficient to provide at least one agitator means, such as vane-type stirrer, an agitator or a Kokeisl stirrer, for stirring the buffered ingredients. 
         [0021]    Both in association with the buffer and with any other surfaces which are exposed to the ingredients, the adhesion of ingredients to any surfaces of the device described herein may additionally be prevented by ejecting a fluid, such as compressed air, towards at least one surface which is exposed to the ingredients and/or the ingredients themselves. Consequently, at least one nozzle for ejecting such a fluid may be provided. In particular, the fluid, such as air, may be ejected as an air blade, in other words, along the blown surface of the wall. Particularly for the buffer tank, ejection of a fluid such as air, which can also be called aeration, has proven efficient in the form of (aeration) pads, i.e. the fluid being ejected over a certain surface. Further, any fouling, particularly of a feed-screw, may be removed “online,” for example, by injecting a fluid, such as air, as a kind of “blade,” e.g. over a length which substantially corresponds to the length of the screw casing, such as 400 mm. The aeration blades and/or pad may, for example, be manufactured by Tridelta Siperm GmbH, Ostkirchstr. 177, 44287 Dortmund, Germany. 
         [0022]    Further, the prevention of adhesion of chocolate ingredients to any exposed surfaces, may be aided by controlling the amount of ingredients delivered. This may, for example, be accomplished by at least one conveyor adapted to convey the ingredients, with which at least one weighing means for continuously weighing the ingredients is associated. Such a weighing means may, for example, be manufactured by Schenck Process GmbH, Pallaswiesenstrasse 100, 64293 Darmstadt, Germany under the trademark Multidos. Thus, the amount of ingredients delivered may be continuously determined and any parameters, such as the conveyor speed, may be continuously adjusted so as to achieve a predetermined target value. This, on the one hand, ensures a sufficient flow of ingredients and, on the other hand, prevents an excessive flow which may result in aggregation of the ingredients and, as a consequence, excessive adhesion and/or sticking of the ingredients. 
         [0023]    As regards one or more of the conveyors involved, it may be advantageous in some situations, to provide a conveyor which is adapted to convey the ingredients in an upward direction. This, for example, allows the ingredients to be dropped into a hopper provided upstream of the feeding screw and, at the same time, withdrawing the ingredients from the lower portion of a buffer tank without requiring excessive space in the vertical direction. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0024]      FIG. 1  is a schematic view of a device for feeding chocolate ingredients to a continuous conche and making a chocolate mass; 
           [0025]      FIG. 2  is a perspective view of the inside of a hopper having a flexible wall; and 
           [0026]      FIG. 3  a perspective view of a hopper. 
       
    
    
     DETAILED DESCRIPTION 
       [0027]      FIG. 1  shows the general layout of a device  10  for feeding chocolate ingredients to a continuous conche  12 . In the embodiment shown, the device  10  comprises a buffer tank  14 , a conveyer assembly  16 , a hopper  18  and a feeding screw  20  for feeding the ingredients to the continuous conche  12 . The ingredients, such as chocolate flakes, are delivered to the buffer tank  14  from one or more refiner (not shown) by one or more conveyors ( 26 ). The buffer tank  14  may have one or more agitators and/or nozzles for injecting a fluid such as compressed air in order to stir the content of the buffer tank  14 . Through an outlet  22  of the buffer tank, the ingredients are removed from the buffer tank  14  and, in the embodiment shown, conveyed by a belt weigher  28  which can be considered a conveyor having weighing means in order to continuously weigh the ingredients removed from the buffer tank  14 . The belt weigher  28  transfers, in the embodiment shown, the ingredients to a first substantially horizontal conveyor  30 , from which the ingredients are taken by an inclined, upwards directed conveyor  32  and a second substantially horizontal conveyor  34  which delivers the ingredients to the hopper  18 . As can be taken from the drawing, the inclination of conveyor  32  allows the buffer tank to be located at a relatively low position, despite the height of the hopper  18 , and, therefore, avoids an excessive space consumption in the vertical direction. However, it is noted that conveyors  30  to  34 , in particular the inclined conveyor  32  may be omitted if space consumption in the vertical direction is not an issue, so that the ingredients may more or less be conveyed in a horizontal direction from the outlet  22  of the buffer tank to a location above hopper  18 . Further, in certain applications, one or more of the horizontal conveyors  30 ,  34  may be omitted. Actually, it is currently preferred to supply the ingredients from buffer tank  14  to hopper  18  by a single, substantially horizontal conveyor, such as conveyor  28 , shown in the figure. 
         [0028]    In the embodiment shown, the ingredients are dropped from conveyor  34  into hopper  18  and end up in a casing  24  from which they are withdrawn by a feeding screw  20 , of which only the casing and not the inner screw is visible in  FIG. 1 . The feeding screw feeds the ingredients to the continuous conche  12 . At the interface between the feeding screw  20  and the continuous conche  12  and/or along the continuous conche  12 , further ingredients, such as cocoa liquor, flavour components, lecithin etc., may be added. The ingredients are mixed, heat is transferred to these as far as necessary along the continuous conche  12 , and the necessary shearing forces are applied to the ingredients, so that chocolate mass leaves the continuous conche at the downstream (in  FIG. 1 , at right) end thereof. It is noted that the casing  24  may accommodate a drive of the feeding screw  20  and/or any screw contained in the continuous conche  12 . Further, weighing means, such as one or more weighing cells may be present along one or more of conveyors  32  to  34  in addition to conveyor  16  in order to continuously weigh the ingredients delivered and adjust the conveyor speed and/or any other parameters as far as necessary. 
         [0029]      FIG. 2  shows an inside view of the hopper  18 , as viewed essentially from above, so that an opening  36  of the hopper and part of the screw  20  are visible. As can be seen in the drawing, any walls  38  forming the opening  36  are made from flexible material and are, in the embodiment shown, formed inflatable. In the embodiment shown, the flexible material even extends to the lower part of the inclined walls of the hopper. By means of inflating means (not shown) the walls  38  may be inflated, so that they move, in the embodiment shown, towards each other and/or deform so as to form one or more bulges extending into the opening  36 . 
         [0030]      FIG. 2  also shows a so-called bridge  40 , which builds across the opening  36  by, firstly, chocolate ingredients adhering to the walls  38 , further ingredients adhering to the ingredients sticking to the walls, and more and more ingredients agglomerating and, finally, building a continuous bridge. If this process continues the entire opening  36  will be blocked. Through the movement and/or deformation of at least one of the walls  38 , mechanical energy is applied to such a bridge  40  in a relatively simple but efficient manner, so that the bridge is destroyed and the described adhering can be prevented, and the flow of ingredients to the feeding screw  20  continues. 
         [0031]    As can be taken from  FIG. 3 , the hopper  18  may have a generally tapered shape with a substantially rectangular upper opening, and also a substantially rectangular lower opening which can already be seen in  FIG. 2 . One or two walls  42 , located between the upper and the lower opening, may be substantially vertical. This also applies to walls, such as a wall  38 , located adjacent, particularly immediately above the lower opening. In particular, all of the wall adjacent the lower opening may be substantially vertical and may have, as shown in  FIG. 3 , a type of double wall structure. For example, there may be inner walls which are substantially continuous with the tapered walls and which may be flexible. Further, the outer walls may have one or more openings shown at  44  for allowing one or more pistons to pass through the openings  44  of the outer walls so as to abut the inner walls. Thus, when one or more pistons are moved towards the opening of the hopper, the engaged inner walls are at least slightly moved towards the opening, so that any bridges, such as shown at  40  in  FIG. 2 , are destroyed. In the embodiment shown, at least one wall  38 , which is substantially parallel to a screw direction A and at least a wall, which is substantially perpendicular to the screw direction A and at the downstream end of the hopper, i.e. not visible in  FIG. 3 , may be flexible to realize the above-described effects, particularly at the downstream end of the hopper. It has been found that the buildups and bridges are particularly critical in that area.