Abstract:
The invention provides methods and systems for molding three-dimensional products from a mass of foodstuff. The systems include a rotatable drum provided with mold holders that accept removable molds that are filled with the mass of foodstuff to form the three-dimensional products. The method includes use of the system to fill removable molds in filling operations to form the three-dimensional products.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation of U.S. patent application Ser. No. 14/312,029 filed Jun. 23, 2014, which issued as U.S. Pat. No. 9,402,413 on Aug. 2, 2016, which is a continuation of U.S. patent application Ser. No. 13/736,213, filed Jan. 8, 2013, which issued as U.S. Pat. No. 8,790,729 on Jul. 29, 2014, which is a continuation of U.S. patent application Ser. No. 13/251,408, filed Oct. 3, 2011, which issued as U.S. Pat. No. 8,367,129 on Jan. 26, 2012, which is a divisional of U.S. patent application Ser. No. 12/555,185, filed Sep. 8, 2009, which issued as U.S. Pat. No. 8,029,841 on Oct. 4, 2011, which is a divisional of U.S. patent application Ser. No. 11/758,567, filed Jun. 5, 2007, which issued as U.S. Pat. No. 7,597,549 on Oct. 6, 2009, which is a continuation of U.S. patent application Ser. No. 10/806,714, filed Mar. 23, 2004, which issued as U.S. Pat. No. 7,284,973 on Oct. 23, 2007, which is a divisional of U.S. patent application Ser. No. 09/863,933, filed May 23, 2001, which issued as U.S. Pat. No. 6,811,802 on Nov. 2, 2004, which is a continuation in part of International Application No. PCT/NL99/00701, filed Nov. 16, 1999, which claims priority to Dutch Application No. 1010630, filed Nov. 23, 1998, the contents of all of which are incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to the field of moulding three-dimensional products from a mass of foodstuff which is suitable for human consumption. In particular, the invention relates to the production of moulded portions of a foodstuff starting from a mass of the foodstuff in question, which mass is of substantially pasty, pulpy consistency. The invention relates in particular to the moulding of edible products from a mass which predominantly comprises pounded meat, in particular chicken or other poultry meat, but also beef, pork, etc. The invention also relates to the moulding of products from fish, dough, etc. 
     BACKGROUND OF THE INVENTION 
     With regard to the processing of poultry meat, the invention is based on the recognition that the processing of poultry produces low-quality meat, for example meat which has been mechanically removed from the bone and meat trimmings, which can be given a higher added value by being upgraded. Also, there is an increasing consumer demand for “moulded meat products”, for example for snacks, and for meat products with an attractive appearance. In these sectors, demand may change quickly, so that it must be possible to adapt the production method according to the invention quickly to meet demand. Furthermore, it is observed that the demand for moulded (meat) products is very high, and consequently it must be possible to achieve a high production capacity. 
     Various methods and moulding machines are known for moulding products from a (meat) mass, and a number of these methods and moulding machines will be described briefly below. 
     U.S. Pat. No. 4,987,643 has described a moulding machine of the “slide-plate” type, for the purpose of producing portions of hamburger meat. A machine of this nature has a substantially planar moulding plate containing a plurality of mould cavities for the meat mass. The moulding plate can be moved to and fro substantially in its horizontal plane for the purpose of displacing the mould cavities between a filling position, in which the mould cavities are filled with meat mass which has been placed under pressure by a meat pump, and a removal position, in which the moulded meat products are removed from the mould cavity. The capacity of a slide-plate machine of this nature is limited in particular by the rate at which the mould plate can be moved to and fro; it is necessary for the mould plate of the known machine to come to a standstill at the filling and removal positions. The speed of movement of the mould plate is limited by the inertia forces which are generated by the heavy mould plate which is moving to and fro and the components which are connected thereto. The reciprocating movement is partly limited by the fact that the mass which is introduced into the mould cavity under a filling pressure has to remain in the closed mould cavity for a certain period in order to obtain the desired cohesion or adhesion of the pieces of meat. The design of these known moulding machines of the slide-plate type has proven unsuitable or, at any rate, disadvantageous for further increasing the production capacity, which would be desirable in view of the increasing demand for moulded meat products. 
     Another known type of moulding machine for meat products and the like is the “turret-type”, an example of which is described in U.S. Pat. No. 4,193,167. In this type of moulding machine, the mould cavities are arranged on a horizontal rotating wheel which can be rotated about a vertical axle. The mould cavities have an opening on the underside of the rotary wheel, so that the mould cavities extend parallel to the axis of rotation of the rotary wheel. Opposite the opening of the mould cavity, this known moulding machine has a mechanically displaceable base, the movement of the base being derived, via a cam-disc mechanism, from the rotation of the rotary wheel. The operation of the associated filling device is synchronized with respect to the rotation of the rotary wheel. In this known moulding machine, the large number of and interaction between the moving components again limits the extent to which the capacity can be increased. Particularly when removing the moulded products, the adhesion of the meat mass to the side wall and the base of the mould cavity represents a problem for operating with success at high speed. The way in which the mould cavities are filled in this known machine also limits the production capacity. 
     Another type of moulding machine for moulding three-dimensional products from a meat mass or the like is the “rotating drum type”. Known moulding machines of this type have a rotatable drum which is driven in continuous rotation by an associated drive, with a plurality of mould cavities on the outside of the drum, which cavities, in a filling position, move past a filling component which is arranged along the outside of the drum and by means of which the mould cavities are filled with (meat) mass. In a removal position, which is located further on in the direction of rotation of the drum, the moulded meat products are driven out of the mould cavities. In this type of machine, the mould cavities are located transversely with respect to the axis of rotation of the drum. 
     Examples of known moulding machines of the “rotating drum type” are described in U.S. Pat. No. 3,504,639, U.S. Pat. No. 3,851,355, U.S. Pat. No. 4,212,609, GB 2,259,043, FR 2,491,734 and FR 2,538223. The development of the moulding machine of this “rotating drum type” is currently not sufficiently advanced for achieving the production capacity required both currently and in the future, and consequently the abovementioned slide-plate moulding machines have the highest capacity and are used for mass production. 
     In the following text, it is assumed that a filling pressure is exerted on the (meat) mass which is to be introduced into the mould cavity in order to fill the mould cavity with a portion of the mass. Therefore, the filling pressure is the pressure which is exerted on the (meat) mass while the mould cavity is being filled. 
     In order to ensure that the (meat) pieces of which the mass consists adhere to one another, thus producing a dimensionally stable product, after the mould cavity has been filled with the (meat) mass, the mass has to be subjected to a fixing pressure for a fixing period which takes place at some point between the time at which the mould cavity is filled and the time at which the moulded product is removed and during which period the portion of the mass is enclosed in the mould cavity. After the fixing period, an edible product which forms a cohesive unit in a three-dimensional shape is obtained, which product can then be removed from the mould cavity. 
     In known moulding machines, such as for example the moulding machine which is described in EP 0,447,003, a portion of the mass is pressed into the open mould cavity by the filling component under a filling pressure. Then, the mould cavity is closed by the fact that the moulding plate with its mould-cavity opening slides away from under the opening of the filling component and moves under a closed top plate. Inevitable leakage from the mould cavity and/or relaxation of the mass in the mould cavity indicates that the pressure of the mass in the mould cavity falls slightly after the cavity has been closed. In the context of the present application, the pressure which then prevails in the closed mould cavity is regarded as being the fixing pressure. This fixing pressure remains present during the displacement of the mould plate until the mould cavity reaches the opening in the bottom plate, with the result that the mould cavity is opened to atmosphere. In this known moulding machine, the fixing pressure is therefore directly and exclusively related to the filling pressure, and it is impossible to control the fixing pressure independently of the filling pressure. Also, the duration of the filling period and the fixing period cannot be influenced independently of one another, since they are both determined by the displacement speed of the moulding plate of the moulding machine. A final drawback is that as soon as the opening in the bottom plate is reached, the mass in the mould cavity, which is still under pressure, immediately seeks to escape from the opening which is increasing in size, and this has an adverse effect on the shape of the product. 
     OBJECT OF THE INVENTION 
     One object of the invention is to provide measures which lead to a treatment of the mass when producing the edible products which is technologically optimum with regard to the (meat) mass which is to be processed. 
     A particular object of the invention is to provide measures which make it possible to control the fixing pressure largely, or preferably completely, independently of the filling pressure. As has been stated, the fixing pressure is one of the principal parameters of the moulding process. By providing devices which allow the fixing pressure to be controlled in this way, it is possible to optimally adapt the operation of each of the said devices to the (meat) mass which is to be processed by the device in question. Thus, there will be an optimum formula for each mass which is to be processed in order to mould products therefrom, and the perimeters of the formula will in principle comprise the time, the pressure and generally also the temperature. In known moulding methods, additives are often added to the edible mass which is to be processed in order in this way to allow the moulding process to proceed as desired, but this increases the cost price, and furthermore such additions are often deprecated by the consumer. For example, if an excessively high (filling and/or fixing) pressure is used or if a pressure is maintained on a (meat) mass for an excessively long period, there is a risk of fat and/or moisture being pressed out and/or of the components which form the mass becoming segregated. Furthermore, high pressures on the edible mass lead to design problems in the devices, such as at the seal which is required for the filling component. 
     It should be noted that the operation of filling the mould cavities, in particular the time involved in filling the mould cavities, is largely dependent on the filling pressure exerted on the mass. Independence of the filling pressure and fixing pressure allows the filling and moulding process to be set up optimally, partly with a view to achieving a high capacity of the device. 
     Furthermore, the methods and devices according to the invention make it possible to process numerous different masses, with the emphasis falling on the processing of meat masses. 
     A further object of the invention is to minimize the filling pressure. For example, in the method provided according to the invention, the filling pressure in the case of pounded meat is between 0.2 and 5 bar, and the fixing pressure is between 1 and 15 bar. 
     A further object of the invention is to provide measures which make it possible to reduce the mechanical load on the (meat) mass when a mould cavity is being filled compared to that which is employed in known moulding machines. This mechanical load is caused in particular by the filling pressure and by shear forces which are exerted on the meat mass, for example, when a stripper moves past the opening of the filled mould cavity. Excessive load on the meat mass damages the structure of the meat and therefore reduces the quality of the product. Furthermore, the shear forces exerted when a stripper of the like moves past may cause an undesirable change in the texture of the product. 
     A further object of the invention is to propose measures which make it possible to produce three-dimensionally moulded foodstuffs for human consumption with a high capacity. A particular object of the invention is to allow the moulding of the products to take place as far as possible in a continuous process, in which the mould cavities move along their path at a substantially constant speed and the filling and emptying of the mould cavities take place as far as possible on a continuous basis. A particular object of the invention is for the moulded products to be removed from the mould cavities without using mechanical ejectors, or with only minimal use of such ejectors. 
     Another object of the invention is to provide solutions for controlling the influence of the viscosity and other relevant properties of the (meat) mass which is to be fed to the mould cavities on the moulding of the product in the mould cavity. In particular, the invention provides for the preparation of the (meat) mass supplied in a continuous process, during which the (meat) mass can, for example, be cooled or heated and additives, such as water, spices, colorants and flavourings, egg whites, can be added. 
     Another object of the invention is to propose measures which make it possible to arrange differently shaped mould cavities on a moulding machine in a simple manner and in a short time, preferably without having to adapt the filling and/or removal system of the moulding machine. The invention also aims to make it possible to produce products of different shapes at the same time using a single moulding machine. 
     A further object of the invention is to propose measures which ensure a high level of hygiene during moulding of the products. 
     Another object of the invention is to propose measures for producing foodstuffs with a product body which is composed of a plurality of parts. This description encompasses, inter alia, layered products, products with an internal filling, etc. 
     A further object of the invention is to provide measures which allow the outside of the products to be treated, for example by the arrangement of a ribbed or grid pattern. 
     The invention also aims to provide a compact device. 
     A further object of the invention is to provide measures which allow the moulded products to be packaged efficiently. 
     SUMMARY OF THE INVENTION 
     The invention provides an improved method for moulding three-dimensional products from a mass of foodstuff which is suitable for human consumption, comprising the steps of: 
     filling a mould cavity with a portion of the mass via a filling opening which is associated with the mould cavity, under the influence of a filling pressure which is exerted on the mass and for a filling period, 
     closing the filling opening of the mould cavity, 
     holding the mass in the closed mould cavity for a fixing period, 
     opening the mould cavity and removing the moulded product. 
     The improvement comprises the use of fixing-pressure-exerting means, which are designed to exert a fixing pressure which acts on the mass in the mould cavity after the filled mould cavity has been closed. 
     The invention furthermore provides devices for carrying out the method and other devices for moulding three dimensional products from a mass of foodstuff. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a diagrammatic cross section through a first exemplary embodiment of a moulding device according to the invention, 
         FIG. 2  shows a diagrammatic cross section through a second exemplary embodiment of a moulding device according to the invention, 
         FIG. 3  shows a diagrammatic perspective view of a third exemplary embodiment of a moulding device according to the invention, 
         FIG. 4  shows a diagrammatic cross section through a fourth exemplary embodiment of a moulding device according to the invention, 
         FIG. 5  shows a diagrammatic cross section through a fifth exemplary embodiment of a moulding device according to the invention, 
         FIG. 6  shows a diagrammatic cross section through a sixth exemplary embodiment of a moulding device according to the invention, 
         FIG. 7  shows a diagrammatic cross section through a seventh exemplary embodiment of a moulding device according to the invention, 
         FIG. 8  shows a diagrammatic cross section through an eighth exemplary embodiment of a moulding device according to the invention, 
         FIGS. 8 a - g    show examples illustrating the filling pressure and the fixing pressure in possible embodiments of the method according to the invention, 
         FIG. 9  shows a diagrammatic cross section through a ninth exemplary embodiment of a moulding device according to the invention, 
         FIG. 10  shows a diagrammatic cross section through a tenth exemplary embodiment of a moulding device according to the invention, 
         FIG. 11  shows a diagrammatic cross section through an exemplary embodiment of a mould according to the invention, 
         FIGS. 12 a , 12 b  and 12 c    show diagrammatic cross sections through further exemplary embodiment of moulds according to the invention, 
         FIG. 13  shows a diagrammatic perspective view of a moulding device of the rotating drum type, possibly in accordance with one of  FIGS. 4-10 , in combination with an exemplary embodiment of the feed means for the mass, 
         FIG. 14  shows a variant on the design shown in  FIG. 13 . 
         FIG. 15 a    shows a diagrammatic, vertical section through an eleventh exemplary embodiment of a moulding device according to the invention, 
         FIG. 15 b    shows a diagrammatic cross section through a twelfth exemplary embodiment of a moulding device according to the invention, 
         FIGS. 16 a  and 16 b    show diagrammatic cross sections through a thirteenth exemplary embodiment of a moulding device according to the invention, 
         FIGS. 17 a - h    show diagrammatic cross sections, in various positions, through the moulding device shown in  FIGS. 16 a  and 16 b   , and 
         FIGS. 18 a  and 18 b    show diagrammatic perspective views of a fourteenth exemplary embodiment of a moulding device according to the invention. 
         FIG. 19  shows a diagrammatic perspective view of a drum having mould cavities positioned in offset rings about the circumference of the drum. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       FIG. 1  shows a first exemplary embodiment of a moulding device  100  according to the invention for producing edible products of three-dimensional shape from an inherently shapeless mass of foodstuff which is suitable for human consumption, in particular a mass of pounded (chicken) meat. The moulding device  100  is of the “rotating drum” type and comprises a rotatable drum  102  which, in an immobile frame (not shown), is mounted in such a manner that it can rotate about an axis of rotation  103 , which in this example is substantially horizontal. The drum  102  is driven at a substantially constant rotational speed in a direction of rotation indicated by arrow A by drive means (not shown). 
     The drum  102  is provided with a plurality of mould cavities  104  which are distributed over the outer circumference and form openings which run all the way through the drum wall  102  and are thus open on both the outer circumference and the inner circumference of the drum  102 . 
     In order to feed meat mass to the mould cavities  104 , an immobile mass-feed or filling component  105  which bears against the inner circumference of the drum  102  is arranged at a mass-feed or filling position. The filling component  105  in this case comprises a connection piece  106  for an extruder or some other form of pumping/mixing device for supplying a pounded (meat) mass under pressure to a chamber  107  which is delimited by walls and has an opening along the inside of the drum  102 . The walls of the chamber  107 , at their edges which adjoin the drum  102 , are provided with suitable sealing means  108 , thus preventing meat mass from leaking out of the chamber  107 . 
     It can also be seen in  FIG. 1  that at least at the location of the filling component  105  the openings of the mould cavities  104  are not closed off on the outside of the drum  2 . As a result, meat mass which is already present in the mould cavities  104  is pushed outwards, so that an outwardly projecting column of meat mass with a cross section which substantially corresponds to the cross section of the mould cavity  104  is formed at each mould cavity  104 . Separating means, which separate a slice from the projecting column, preferably along the surface of the drum  102 , are active at a removal position in the vicinity of the underside of the drum  102 , above a moving belt  109  or some other conveyor mechanism for discharging the moulded products. In this example, a taut cutting wire  110  is arranged in a stationary position along the underside of the drum  102 , which wire cuts off the moulded product “p”, which then falls onto the belt  109 . When this takes place, meat mass remains behind in the mould cavity  104 , which meat mass is cut off when it moves past the cutting wire  110  one or more times. In a variant, there may be provision for the separating means to comprise an actuable separating component arranged on the outside of the drum  102  for each mould cavity  104 , in order to cut off the outwardly projecting column of meat. This is diagrammatically indicated at  111  in  FIG. 1 . 
     Furthermore, there may be provision for one or more stations  112  to be arranged along the outside of the drum  102  for the purpose of treating the outer surface of the meat mass which is present in the mould cavities  104 , for example for applying an additive to the said surface, for example breadcrumbs, a colorant or flavouring, etc. This operation could also, for example, involve applying a certain pattern to the meat mass. 
     There may also be provision for one or more stations  113  to be arranged in the interior of the hollow drum  102  for the purpose of treating the inner surface of the meat mass which is present in the mould cavities  104 , for example for applying a layer which prevents or reduces adhesion to the meat mass which is subsequently to be placed into the mould cavity  104 , so that the product “p” may come free from the meat mass which remains behind in the mould cavity at the removal position without the use of separating means. By way of example, a breadcrumb material could applied for this purpose. 
       FIG. 2  shows a variant on  FIG. 1 , and components which correspond to the components shown in  FIG. 1  are denoted by the same reference numerals; for a description of how they operate, reference is made to the preceding text. 
     In  FIG. 2 , there is provision for a fixing pressure to be exerted on the meat in the mould cavities  104 , and this is achieved by closing the mould cavities on one side by means of a closure component  114 , which in this case bears against the outer circumference of the drum  102 , and exerting a controllable fixing pressure on the meat mass in the mould cavity from the other side. 
     In this example, the chamber  107  of the filling component  105  is divided into two chambers  107   a ,  107   b , each with an associated connection piece  106   a ,  106   b , for example for an extruder belonging to each of the connections. The closure member  114  is arranged opposite the chamber  107   a , on the outside so that a fixing pressure which provides the meat material with the desired cohesion can be generated in the chamber  107   a . Then, in the chamber  107   b , where the meat is subjected to a filling pressure which is lower than the fixing pressure, further meat material is pressed into the mould cavity  104 , which is then open again on the outside. Given a suitable arrangement, only meat material which has been subjected to the fixing pressure and compressed is then separated at the separating position. 
     It will be clear that the closure member  114  may, as an alternative to the stationary plate shown here, also be a moving belt, as will be described below, and may also bear against a larger part of the drum, the same also applying to the chamber  107   a . If appropriate, masses of different composition may be fed to the chambers  107   a  and  107   b , resulting in a layered structure of the product p. 
       FIG. 3  shows a moulding device  120  with a drum  122  which can rotate about a substantially horizontal axis and is driven in the direction of arrow B by drive means (not shown). A filling component  125  with a wall which, together with the inner wall of the drum  122 , delimits a chamber  127  to which a (meat) mass is fed in a manner not indicated, for example by means of an extruder, is located in a stationary position in the drum  122 . The drum  122  is provided with continuous passages  124  which are distributed over the circumference and extend through the wall of the drum  122 . A slideable moulding component  128  is arranged on the outside of the drum  122  for each passage  124 . Each slideable moulding component  128  has a mould holder  129  which is arranged on the drum  122  and contains an opening for a sliding mould  130  which can be slid to and fro. In the retracted position of a mould  130 , (meat) mass can be introduced into the mould  130  via the associated passage  124  when it moves past the filling component  125 . Then, the mould  130  can be slid out of the associated holder  129 , an operation which in this case is carried out by means of curved track  131 , against which the moulds  130  bear under springloading or the like. 
     When the mould  130  has been sufficiently extended in the removal position at the bottom of the drum  122 , the moulded product p falls out of the mould  130  onto the discharge belt  133 . If appropriate, removal of the product p from the mould  130  can be assisted by means of compressed air or some other ejector means. 
     It will be clear that the filling component  125  may also be positioned along the outer circumference of the drum  122 , with the sliding moulds  128  on the inside of the drum  122 . 
       FIG. 4  shows a fourth exemplary embodiment of a moulding device  1  according to the invention for moulding three-dimensional products from a mass of foodstuff which is suitable for human consumption, in particular a mass which predominantly consists of pounded (chicken) meat. The moulding device  1  is of the “rotating drum” type and comprises a rotatable drum  2  which, in a stationary frame (not shown), is mounted in such a manner that it can rotate about an axis of rotation  3 , which in this case is substantially horizontal. The drum  2  is driven, preferably at a substantially constant rotational speed, in a direction of rotation which is indicated by arrow A, by drive means (not shown). 
     The drum  2  has a substantially cylindrical drum wall with a diameter which is, for example, between 0.15 and 0.7 meter and a length which is, for example, between 0.3 and 2 meters. The considerable length of a drum  2  of this nature is possible in particular because of the tubular shape of the drum  2 , which tubular shape is very stable with respect to the forces which are generated during the moulding process. These forces, which are generated in particular by the filling pressure with which the mass is pressed into the mould cavities and the fixing pressure, in principal cause the drum  2  to bend, which causes problems in particular for seals which bear against the inside and/or outside. 
     Preferably, the drum  2  is formed from a metal tube which is commercially available as standard, but it will be clear that the drum  2  may also be assembled from sections or, for example, from a special casting. The drum may also be provided with internal reinforcements, for example reinforcement plates which are located at axial distances from one another. 
     The drum  2  may also be formed by a plurality of tubes which slide into one another, which structure is advantageous for the arrangement of connecting passages, in particular for compressed air and/or vacuum, which lead to the mould cavities  4 . These passages could then be arranged substantially as grooves in the walls of the said tubes. 
     The bending can be reduced by providing the drum  2  with prestressing means which generate an axial prestress in the drum wall and thus reduce any bending. The bending can also be reduced by making use of one or more robust support rollers which bear against the drum wall, for example in the interior of the drum opposite the filling device  5 , in order in this way to absorb the forces which the filling pressure exerts on the drum  2 . 
     The drum  2  is provided with a plurality of mould cavities  4  which are distributed over the outer circumference and are open on the outer circumference of the drum  2 . By way of example, the mould cavities  4  are arranged in a pattern with a plurality of circumferential rings, located next to one another in the longitudinal direction of the drum  2 , of similar mould cavities. There may also be provision for the mould cavities  4  in each ring to be distributed at equal angular intervals around the circumference of the drum  2 , in which case the mould cavities  4  of adjacent rings are always offset in the circumferential direction (see  FIG. 19 ). Such an arrangement of the mould cavities leads to mould cavities being filled virtually continuously, instead of groups of mould cavities being filled simultaneously, with a time gap between filling operations. This manner of continuous filling, particularly with a continuous supply of mass to the filling component, for example by an extruder, leads to a uniform filling pressure. This arrangement will also deliver a continuous stream of moulded products. 
     Obviously, it is also conceivable for mould cavities  4  of different shapes to be arranged on the drum  2 . In this case, the mould cavities may be of any conceivable form, for example circular or rectangular, but also in novelty shapes, such as in the shape of a Christmas tree, a crescent, a star, a triangle, etc. In an advantageous embodiment, one or more mould cavities may form part of a removable mould which can be releasably attached to the drum. This may, for example, be achieved by providing the drum  2  with a large number of identical holding features around its outer circumference, for example openings arranged in the drum wall and/or coupling means positioned on the outer circumference, a mould fitting into each holding facility, in which case a large number of moulds belong to the moulding machine and are identical insofar as they can be positioned on the drum by means of the holding facilities, but have mould cavities of different designs. 
     If different mould cavities  4  are arranged on the drum  2 , it is possible, by selecting a suitable arrangement of the said mould cavities  4 , to ensure that the differently shaped products do not have to be handled, or scarcely have to be handled, during subsequent processing. For example, it is conceivable to produce sets of three products of different shapes and to supply these sets in a single pack. In this case, it may be advantageous for the three different mould cavities to be arranged next to or immediately after one another on the drum, so that the products are delivered by the moulding device in sets of three. 
     As an alternative to the drum, it is also possible, albeit with a higher level of technical complexity, to provide for the moulds, each with one or more mould cavities therein, to be arranged on a common turret which defines a loop-like movement path for the moulds, in which case drive means are provided, which move the moulds along the movement path. Preferably, in this case, the drive means move the moulds at a substantially constant speed along the movement path. The loop-like movement path may in this case be a circle, as with the drum, but other forms are also easy to achieve in practice, such as for example a path with two straight sections which are connected at their ends via 180° bends. 
     To feed a portion of meat mass to the mould cavities  4 , a stationary mass-feed or filling component  5 , which bears against the outer circumference of the drum  2 , is arranged in a mass-feed or filling position, in this case in the vicinity of the top side of the drum  2 . The filling component  5  in this case comprises a connection piece  6  for an extruder or some other form of pump device for supplying the meat mass under pressure to a chamber  7  which is delimited by walls and has an opening on the side of the drum  2 . At their edges which adjoin the drum  2 , the walls of the chamber  7  are provided with suitable sealing means  8 , making it possible to prevent meat mass from leaking out of the chamber  7 . The filling component  5  shown is in fact intended to completely fill the mould cavity. In another embodiment (not shown), the filling component may also be designed to feed a predetermined portion to the mould cavity, for example on the basis of the volume and/or mass of the portion, the volume of which portion may therefore be smaller than the volume available in the mould cavity. For example, a filling component of this nature moves a slice or other preformed shape of the foodstuff which is to be processed into the mould cavity. 
     It can also be seen from  FIG. 4  that the moulded products “p” are removed from the mould cavities  4  at a removal position, in this case in the vicinity of the underside of the drum  2 , above a conveyor belt  9  or other conveyor mechanism for discharging the moulded products. This ejection may be effected by the force of gravity, as illustrated in  FIG. 4 , but owing to the adhesion of the meat mass to the walls of the mould cavities  4 , the removal is preferably facilitated or assisted in ways which are to be described in more detail below. 
     The filling component  5  ensures that a portion of the meat mass is moved into a mould cavity  4  at a defined filling pressure. To obtain firm cohesion between the pieces of meat, so that ultimately a stable product is obtained, it is necessary, after the mould cavity  4  has been filled, to exert a fixing pressure on the meat mass for a defined period. For this purpose, there is provision for the filling openings, which are located on the outside, of the mould cavities  4  to be closed off over at least part of the path between the filling component  5  and the removal position, preferably over virtually the entire path. 
     In this case, the mould cavities  4  are closed off with the aid of a flexible belt  10  which, in the path in question, bears against the outer circumference of the drum  2  and preferably moves with the drum  2 . The belt  10  runs around a top roller  11 , which is arranged in the vicinity of the filling component  5  or even, with the belt  10  wrapped around it, forms part of the walls of the chamber  7  of the filling component  5 . In the vicinity of the removal position, the belt  10  runs around a bottom roller  12  and also runs around a tensioning roller  13  which supports the return section of the belt  10 . If appropriate, a separate drive for the belt  10  may be provided. It is also possible to provide cleaning means which clean the belt  10  in its return section. 
     Closing the mould cavities  4  with the aid of the belt  10  bearing against the drum  2  ensures that the meat mass in the mould cavities  4  is placed and held under a fixing pressure, with the result that the desired cohesion and mutual adhesion of the (meat) pieces is obtained. In the embodiment shown in  FIG. 4 , the fixing pressure is obtained by the fact that the convex side of the mass which is produced at the filling component  5 , is, as it were, pressed flat into a mould cavity  4  by the belt  10 , with the result that the mass is placed and held under a fixing pressure in the closed mould cavity  4  throughout the time during which the belt  10  closes off the mould cavity  4 . 
     The device shown in  FIG. 4  also allows the outside of the moulded product to be treated, in particular along the path between the location where the outside is no longer covered by the belt  10  and the moment at which the product is ejected. For example, a spraying device could be used to apply a layer to the product. As soon as the product rests on the discharge belt, the other side could also be treated. 
       FIG. 5  shows a fifth exemplary embodiment of a moulding device according to the invention. Where components correspond to the components shown in an embodiment described above, these components are denoted by the same reference numerals; reference is made to the preceding text for a description of how they function. 
     In  FIG. 5 , reference  15  denotes a film-feed mechanism for feeding film. This preferably thin, flexible (plastic) film  17  is placed against the outside of the drum  2  at a film-placing position  16 , which is upstream of the filling component  5 , as seen in the direction of rotation, and serves to ensure that at least the walls and the base of the mould cavities  4  are covered by the film  17 . 
     To ensure that the amount of film  17  present at each mould cavity  4  of the device is such that this film  17  is able to bear taut against the base and the side wall of the mould cavity  4  when the meat mass is introduced into the mould cavity  4 , vacuum means are provided here, which, between the film-placing position  16  and the filling component  5 , remove air from the mould cavity  4  which is covered by film  17 . The vacuum means in this case comprise a tray  18  which is arranged in a stationary position in the rotating drum  2  and is formed by a wall which in part lies at a distance from the inside of the drum and at its edges bears in a sealed manner against the inside of the drum  2 , so that a closed space which is delimited by the wall of the tray  18  and the inside of the drum  2  is formed. This closed space is connected to a vacuum pump or the like, so that a reduced pressure can be generated in the tray  18 . Furthermore, the drum  2  is provided at each mould cavity  4  with a connecting passage  19  which connects the mould cavity  4  to the inside of the drum  2 , so that at the moment at which a mould cavity  4  reaches the tray  18  air is sucked out of the mould cavity  4  via the associated passage  19 , while the opening of the mould cavity is already covered by the film  17  on the outside of the drum  2 . Partly because of the appropriate flexibility of the film  17 , the film  17  matches the shape of the mould cavity  4 . In this example, this suction on the film  17  is maintained until the filling component  5  fills or has filled the mould cavity  4 . 
     The film  17  prevents the meat mass from sticking to the drum  2 , which is particularly relevant for removal of the moulded product and also prevents contamination to the drum  2 . Furthermore, the film  17  can be used to eject the moulded product from the mould cavity  4 , for example by exerting a pulling force on the film  17  in the vicinity of the removal position, an operation which can be achieved, for example, by (temporarily) rapidly rotating a pulling roller  20  against which the film  17  bears, thus exerting tension on the film  17 . 
     If the product p sticks to the film  17 , it is preferable to guide the film  17  through a sharp bend, for example around bar  20   b , so that the film  17  moves into a position in which it is approximately at right angles to the surface of the product and is thus stripped off from the surface of the product. 
     The passages  19  may also be used to eject the moulded product by introducing compressed air into the mould cavity  4  beneath the film  17  via the said passages  19  at the removal position. This may be effected using excess-pressure tray  22 , which is positioned in the drum  2  in the vicinity of the removal position. The tray  22  is arranged in a stationary position and bears in a sealed manner against the inside of the drum  2 , and is connected to a compressor (not shown) for feeding pressurized air (or another gas) to the tray  22 , with the result that the product and the film  17  are pressed out of the mould cavity  4 . If appropriate, there may be provision for the tray  22 , as seen in the direction of rotation of the drum  2 , to be divided into a plurality of compartments  22   a ,  22   b  by means of one or more partitions  21 , in which case the gas pressure can be adjusted separately in each compartment  22   a ,  22   b . This makes it possible to successfully control the ejection of the moulded product. Incidentally, the same measure may also be used for the reduced-pressure or suction tray  18 . 
     In a variant which is not shown, there may be provision for a medium to be pressurized in the mould cavities  4  via the passages  19  in the path in which the mould cavities  4  are closed off on the outside by the belt  10 . This may, for example, be achieved by arranging an excessive-pressure tray, corresponding to tray  22 , which is divided into one or more compartments at that location but on the inside of the drum  2 . Then, by suitably regulating the pressure of the medium, it is possible to control the fixing pressure in the mould cavities  4 . The mould cavities  4  may, for example, be designed in the manner which will be explained in more detail below with reference to  FIGS. 11, 12   a  and  12   b.    
     The film  17  is, for example, disposable and is guided onto a reel and wound up after it has run around the drum, after which a reel of used, dirty film is removed and destroyed. However, the film  17  could also be used for packaging the product. 
       FIG. 5  also shows a station  25  which is arranged along the outside of the drum  2 , between the film-placing position  16  and the filling component  5 . The station  25  may, for example, be used to apply a coating or the like to the film  17 . This coating may be in a wide variety of forms, for example may be a liquid substance which influences the adhesion between the meat and the film  17 , or an edible coating which is intended to influence the appearance of the outer layer of the moulded product, for example a coating containing breadcrumbs and an egg-white emulsion, a colorant or flavouring etc. The station  25  may comprise liquid sprayers and/or atomizers, which only operate when a mould cavity  4  covered by film  17  moves past, and/or a fan or other blowing device for blowing more or less solid edible particles, for example edible flakes, onto the film, which may previously have been moistened. 
     In a variant on the device  1  described above, the reduced pressure acting on the film  17  is eliminated after it has been sucked under vacuum into the mould cavity  4 , before the filling device  5  is reached, so that the film  17  is again approximately in the plane of the opening of the mould cavity  4 . The aim of this is to ensure that the meat mass bears against the film  17  without the inclusion of air in the vicinity of the filling device  5  and moves into the mould cavity  4  together with the film, during which operation, if appropriate, reduced pressure is again exerted via passage  19 . This procedure can be achieved by providing the tray  18  with the partitions  18   a ,  18   b  as shown in  FIG. 5 . 
     It should be noted that the step of firstly sucking the film  17  into the mould cavity  4  before the filling device  5  is reached is important in order to ensure that sufficient film material collects at the location of the mould cavity  4 . If the film  17  were to be in a taut position above the opening of the mould cavity  4  when the mould cavity is being filled, it is impossible, or virtually impossible, to feed film material when the meat mass is pressed into the mould cavity  4 , so that a very high level of elasticity of the film  17  would be necessary in certain areas, in particular around the edge of the mould cavity  4 . 
     To avoid air being enclosed between the film  17  and the meat mass, use could also be made of steam or another condensable gas. In that case, a steam tray, for example, would be placed against the outside of the drum, immediately upstream of the filling component  5 . Consequently, steam will be included between the film and the meat mass, but this steam will rapidly condense to form a minimal quantity of water. 
     As an alternative, it is possible for the belt  9  to be covered with a film which moves with it and onto which the products fall. This film could then, for example, form part of the packaging for the products. 
       FIG. 6  shows a variant on the device shown in  FIG. 5 , in which the principal change is that the device is positioned upside-down. Consequently, the filling component  5  is now located in the vicinity of the underside of the drum  2 . A second web of film  17   b  is fed to the top side and is guided over the drum  2 , so that the moulded products, which are still enclosed in the mould cavities  4 , are enclosed between the two films  17  and  17   b.    
     In this example, a film-welding device  23  is also arranged in the vicinity of the top side of the drum  2 , which film-welding device welds the two layers of film  17 ,  17   b  together, for example around each cavity  4 , so that the product is packaged in film while it is still inside the mould cavity. If appropriate, the film layers  17 ,  17   b  are cut or melted through around the outside of the weld, so that the product enclosed in film is detached from the two layers of film. The product which is packaged in film is then discharged by means of the excess-pressure tray  22  or some other removal mechanism. Obviously, it is conceivable that the product will be enclosed between the two film webs  17 ,  17   b  only at a later stage, after the products lying on the film  17  have been removed from the mould cavities  4  of the device. The separation of the products which are packaged in film from the film webs may also take place at a later stage, so that the film webs can still be used as a mechanism for conveying the packaged products. One advantage of the device shown in  FIG. 6  is the height at which the products are removed, which makes it easy to provide connection to subsequent stations. 
       FIG. 7  shows a seventh exemplary embodiment of a moulding device according to the invention. Where components correspond to the components shown in an embodiment which has been described above, these components are denoted by the same reference numerals; reference is made to the preceding text for an explanation of how they function. 
     In  FIG. 7 , there is provision for a film  30  to be placed between the belt  10  and the drum  2 , which film  30  moves with the drum  2  and the belt  10 . This measure allows the film  30  and the belt  10  each to have different properties which are adapted to their specific tasks. In particular, the film  30  in this case serves as a protection for protecting the belt  10  from the (meat) mass in the mould cavities  4 , so that the belt  10  does not come into contact with the (meat) mass and is therefore not contaminated and also does not have to be cleaned. 
     In this example, the film  30  is intended for single use and is supplied from a supply reel  31  and then runs around the top deflector roller  11  of the belt  10  via guide roller  32 . In this example, the film  30  also runs around the bottom deflector roller  12  of the belt  10  and is then separated from the return section of the belt  10  via guide roller  33  and is wound onto a discharge reel  34 . However, it is also possible for the film  30  to remain in position against the products when the moulded products are ejected and to be used to discharge the products, and if appropriate even for handling the moulded products in further processing devices and/or for packaging the products. 
     For example, it is possible for the conveyor  9  to be provided with openings in its belt and for a reduced-pressure tray  35  to be positioned beneath the belt  9  in the vicinity of the ejection position of the products, so that the film  30  can be sucked onto the belt  9  and can be moved with the belt  9 . In this case, the products continue to lie on the film  30 . This has the advantages that the conveyor  9  is not contaminated, that the moulded product is supported when it is ejected from the drum, and that the position of the product on the film  30  is fixed, which may be advantageous for any subsequent processing operations. 
     In a variant which is not shown, the film  30  is also designed as an endless loop, i.e. in the same way as the belt  10 , in which case, for example, there is provision for the film  30  to be cleaned. Incidentally, in these illustrations, the film is always shown and described as being considerably thinner than the belt, although it is equally conceivable for the components described as film and belt to be of similar thickness. 
       FIG. 7  also shows the station  25  with which, for example, the mould cavities  4  can be cleaned before they are refilled. If appropriate, a non-stick agent may also be arranged in the mould cavities  4 , or some other means may be provided, such as that illustrated in  FIG. 5 . Obviously, the devices shown in  FIGS. 5, 6 and 7  can also be combined to form a single device, in which the portions of meat mass in the mould cavity  4  are completely surrounded by the two films  17  and  30 . 
     In a further variant, the discharge belt  9  with the tray  35  bears against the drum  2  and the belt  9  is moved at the same speed. As a result, the product is, as it were, sucked firmly onto the belt  9  while it is still in the mould cavity  4 , and then the product is gradually removed from the mould cavity. 
       FIG. 8  shows an eighth exemplary embodiment of a moulding device according to the invention. Where components correspond to the components shown in an embodiment which has been described above, these components are denoted by the same reference numerals; reference is made to the preceding text for a description of how they function. 
     In  FIG. 8 , instead of the disposable film  17  as described with reference to  FIG. 5 , a belt  40  of elastically deformable (plastic) material is used, which belt bears against the outer circumference of the drum  2  from a placing position  41  upstream of the filling component  5  to the area of the removal position of the products, on the underside of the drum  2 . The belt  40  is used, inter alia, to cover the base and the side walls of the cavities  4 , so that these parts do not come into direct contact with the (meat) mass. 
     To enable the belt  40  to be moved into the mould cavities  4 , the reduced-pressure tray  18  is again provided, as are the associated connecting passages  19  in the drum wall leading to the mould cavities  4 . By applying reduced pressure, the belt  40  can thus be deformed so that it bears against the delimiting walls of the mould cavities  4 . 
     Preferably, the belt  40  is of an elastic quality which is such that it restores its shape, i.e. the belt  40  is preferably designed in such a way that it returns to its original planar form when no external force, such as the vacuum, is being exerted thereon; this can be clearly seen in  FIG. 8 . 
     Preferably, the belt  40  is cleaned in the section in which this belt  40  is clear of the drum  2 . 
     Due to the shape-restoring properties of the belt  40 , it is preferable for the reduced pressure generated by the tray  18  also to act while the mould cavities  4  are being filled. The shape-restoring property of the belt  40  can also be utilized when the shaped product is being removed from the mould cavity  4 , if appropriate with the assistance of a tensile force being exerted on the belt  40 , which force pulls the belt  40  back into a flat state in this position. Furthermore the removal of the product from the mould cavity  4  can be assisted by pressing air between the belt  40  and the drum  2  via excess-pressure tray  22 . 
     The belt  40  can also be used to control the fixing pressure in the mould cavities  4  in the path between the filling component  5  and the ejection position. For example, the reduced pressure between the belt  40  and the drum  2  can be partially or completely eliminated in that path; it is even possible to produce an excess pressure, for example by means of the tray  43 , which is of similar design to the trays  18  and  22  and may be divided into a plurality of compartments with separately adjustable pressures by means of partitions. 
     As an alternative to the trays  18 ,  22  and  43  shown in  FIG. 8 , it is also possible for the connecting passages  19  which lead to the mould cavities  4  and connect these mould cavities  4  to an excess-pressure source or a reduced-pressure source or atmosphere as desired to be designed in a different way. By way of example, these connecting passages  19  may be coupled via rotatable couplings to excess-pressure and/or reduced-pressure pipes or vent pipes which are positioned on the axis of rotation of the drum  2 . The connecting passages  19  could also lead, in or along the drum wall, to one or both ends of the drum, where they could be connected to stationary lines leading to the abovementioned sources or to atmosphere, as is known, for example, from U.S. Pat. No. 4,212,609. 
     It will be clear that a combination of the devices shown in  FIGS. 8 and 7  is possible, as is a combination of the devices shown in  FIGS. 8 and 5 , thus preventing contamination of the belt  40 . 
     At the location of the ejector tray  22 , the discharge belt  9  runs past the drum  2  at a short distance therefrom, so that the product comes into contact with the belt  9  while it is still largely inside the mould cavity  4 . In this case, the belt  9  is driven at the same speed as the drum  2 . The downstream section of the belt  40  gradually runs away from the discharge belt  9 , so that the product p is released from the belt  40  and stands on the belt  9 . At the end of this section of belt  40  there is a roller  50  of small diameter, so that the belt  40  runs through an acute angle and is thus pulled off the product p. 
     Depending on the composition of the mass which is to be moulded, it will also be possible to use the device shown in  FIG. 8  without the presence of the belt  40  or a film with similar function, as explained with reference to  FIG. 5 . In order, in such a case, to make it possible to realise the fixing pressure by means of gas pressure and/or to eject the moulded product, it is possible to provide for the base of the mould cavity to be covered with a “sealed” layer by means of a suitable feed apparatus upstream of the filling component. This layer could, for example, be a disc of solid material, for example paper or an edible material such as a pastry product, but could also, for example, comprise a liquid which sets, for example fat, which is then introduced into the mould cavity and solidifies to form an impenetrable layer. Thus, this layer in fact functions as a “plunger” in the mould cavity. 
     When ejecting the product from the mould cavity, it may be advantageous to cool the product on the outside, for example by carrying out the ejecting operation using gaseous nitrogen. The cooling leads, inter alia, to shrinkage of the product, and consequently it will often come out of the mould cavity more easily. 
     The main concept of the invention will now be explained in more detail with reference to the device shown in  FIG. 8 , which concept relates to the control of the important technological perimeters associated with the moulding process. 
     By means of the filling component  5 , a mould cavity  4  is completely filled with the (meat) mass which is fed to the filling component  5 , for example via an extruder or a pump. In the process, the mass is subjected to a filling pressure, so that the mass flows into the mould cavity  4 . The mould cavity  4  is preferably filled using a filling pressure which is uniform over time and is preferably low. If appropriate, additional filling-pressure control means may be provided, which seek to keep the pressure in the chamber of the filling component at a virtually constant level. 
     When the mould cavity  4  is full, the mass contained therein is still subject to the filling pressure, the duration of which is dependent on the speed of the drum  2  and the length of the opening of the filling component  5 , measured in the circumferential direction. If appropriate, this length is adjustable in order to be able to regulate the filling period. 
     After filling, the mould cavity  4  is closed off by means of the belt  10 , which belt  10  extends over part of the circumference of the drum  2 . The combination of the length of that part of the circumference and the rotational speed of the drum leads to a maximum duration of the fixing period during which the mould cavities are closed off and a fixing pressure can be exerted on the mass contained therein. By then introducing pressurized gas or liquid beneath the belt  40  via the connecting passages  19 , the mass which is present in the closed mould cavities  4  is subjected to a fixing pressure, so that the pieces which form the mass adhere to one another. In the device shown in  FIG. 8 , the actual duration of the fixing period may, for example, be set by separately regulating the feed of gas or liquid to each of the compartments of the tray  43 ; thus, it is conceivable, for example, for as yet no pressurized liquid or gas to be fed to that compartment of the tray  43  which is located immediately downstream of the tray  18 . 
     In a variant which is not shown, the device allows the length over which the belt  10  covers the drum to be adjusted, for example by moving the rollers  12  and  13 , so that in this way too it is possible to adjust the duration of the fixing period without having any effect on the duration of the filling period. 
     It will be clear that the device shown can be used to manipulate the filling pressure and fixing pressure, as well as the duration of the filling period and of the fixing period, and furthermore also the transition from the filling period to the fixing period as desired, in order to obtain an optimum result for the mass which is to be processed. 
       FIGS. 8 a - d    show four possible variants for the filling-pressure curve over time, and  FIGS. 8 e - g    show three possible variants for the profile of the fixing pressure over time, it being clear that in the actual process the fixing pressure follows the filling pressure which has previously been exerted and in principle any desired combination is possible. It should be noted that the profiles shown are only examples and that the process can be adjusted optimally for each mass, for example on the basis of tests carried out using the mass which is to be processed. 
     In  FIG. 8 a   , the filling pressure is completely eliminated after the mould cavity has been filled; this may, for example, be achieved by bringing the filling opening of the mould cavity into contact with the atmosphere. 
     In  FIG. 8 b   , the filling pressure is maintained for a longer time than in  FIG. 8 a   , for example by extending the distance over which the moving mould cavity is moving past the filling component or by lowering the speed at which it moves past. The filling pressure then falls to atmospheric pressure. 
     In  FIG. 8 c   , the filling pressure is maintained without falling to atmospheric pressure, after which a higher fixing pressure can be exerted on the mass. 
     In  FIG. 8 d   , the filling pressure falls slightly at the end of the filling period, but not to atmospheric pressure. 
     In  FIG. 8 e   , the fixing pressure is only maintained for a short fixing time. In this case, the fixing pressure will usually be higher than the filling pressure which has previously been exerted. 
     In  FIG. 8 f   , the fixing pressure is maintained for a longer time. In this case too, the fixing pressure will usually be higher than the filling pressure, but since both the duration of the fixing period and the fixing pressure are parameters, it is also conceivable for the fixing pressure, for example temporarily, to be lower than the filling pressure. 
       FIG. 8 g    shows how the fixing pressure can be varied during the fixing period, for example can be reduced in steps. To avoid the possibility of the mass which is still under pressure expanding when the mould cavity is opened, directly at the location where the opening forms, it may be advantageous to reduce the fixing pressure in the final phase of the fixing period to atmospheric pressure or even to below this pressure. 
     It will be clear that the fixing pressure may also have an entirely different profile, for example may initially rise and then fall again. 
       FIG. 9  shows a ninth exemplary embodiment of a moulding device according to the invention. Where components correspond to the components in accordance with an embodiment which has been described above, these components are denoted by the same reference numerals; reference is made to the preceding text for an explanation of how they function. 
     In  FIG. 9 , the fixing pressure is regulated in the path between the filling component  5  and the removal position by regulating the pressure with which the belt  10  is pressed against the meat portions accommodated in the mould cavities  4 . To this end, a controllable pressure, for example an air pressure or a liquid pressure, is preferably exerted on that side of that part of the belt  10  which bears against the drum  2  which is remote from the drum  2 . In this case, this is achieved by placing a closed tray  51  against the belt on that side, which tray forms a chamber  52 , one side of which is delimited by the belt  10 . By connecting the tray  51  to a suitable source of pressurized medium, for example an air compressor, the pressure in the space formed by the tray  51  and the belt  10  can be adjusted, and thus the pressure with which the belt  10  presses against the portions of meat in the mould cavities  4  can be regulated. 
     Obviously, it is conceivable to divide the tray  51 , by means of one or more partitions, into compartments which preferably form pressure compartments which lie one behind the other in the direction of rotation of the drum  2 , so that different fixing pressures can be implemented at different moments during the fixing period of the product. 
     It will be clear that the measure in accordance with  FIG. 9  can be combined with preceding exemplary embodiments. 
     The belt  10  may be provided with a profile on the outside, in such a manner that this profile forms a complementary pattern on the outside of the products, for example a studded, ribbed or grid profile. 
     In order to provide the outside of the product with the appearance of having been grilled on a grate, it is also possible to provide a heated stamp with a suitable pattern along the drum  2 , which stamp is pressed against the products which are still enclosed in the mould cavities  4 . Obviously, this feature can also be provided in the device shown in  FIG. 8 . 
       FIG. 10  shows a tenth exemplary embodiment of a moulding device according to the invention. Where components correspond to the components shown in an embodiment described above, these components are denoted by the same reference numerals; reference is made to the preceding text for an explanation of how they function. 
     In  FIG. 10 , the bases of the mould cavities  4  are designed in the form of a flexible membrane, which in this case is achieved by designing the mould cavities  4  as openings which run all the way through the wall of the drum  2  and by covering the inside of the drum wall with a cylindrical membrane  60 . At the filling component  5 , an excess hydrostatic pressure is exerted on the inside of the membrane  60 , in such a manner that the membranes  60  yields outwards and projects partially into the mould cavity  4 . In this case, the excess pressure is produced using an excess-pressure tray  62 . The filling component  5  then introduces a portion of meat into the mould cavity  4 , this portion in fact being smaller than the actual volume of the mould cavity. 
     After the mould cavities  4  have been filled, i.e. downstream of the filling component  5 , the excess pressure on the inside of the membrane  60  is eliminated and, if appropriate, a reduced pressure is generated using reduced-pressure tray  63 . As a result, the base of the mould cavity  4  moves inwards. This inwardly directed movement of the base of the mould cavity  4  is intended to compensate for the expansion of the portion of meat, which expansion occurs as soon as pressure is no longer being exerted on the portion of meat on the outside of the drum  2 . The elasticity of the meat mass, which is partially caused by the air which is present in the meat mass, would otherwise lead to the meat moving out of the mould cavity  4  on the outside and forming a “head” which projects outside the circumference of the drum  2 . By moving the base inwards, this expansion is able to take place without the said head being formed, and it is possible that a hollow may even form in the outside of the portion of meat in the mould cavity  4 . The absence of the head prevents the said head from being spread out as a result of coming into contact with the belt  10 , which would result in the loss of meat material and rapid contamination of the moulding machine. If appropriate, the base of the mould cavity is not moved outwards before the mould cavity is filled, and the above-described compensation for the expansion of the mass takes place entirely by moving the base inwards. 
     As soon as the belt  10  lies over the outer opening of the mould cavity  4 , the fixing pressure can be generated in the mould cavity, which is then closed on all sides. This may, for example, be achieved by exerting an excess pressure on the inside of the membrane  60  with the aid of excess-pressure tray  64 . Also, if appropriate in combination with the above, an excess pressure could be exerted on the outside of the belt  10 , as described with reference to  FIG. 5 . Excess-pressure tray  65  could assist with ejection of the product. 
     It will be clear that the concept described with reference to  FIG. 10  of moving the base of the mould cavity into an outer position prior to or during filling of the mould cavity and then moving it into an inner position after the mould cavity has been filled and before the belt or a fixed closure member which bears against the outside of the drum is reached, closing off the mould cavity on that side, can also be implemented in moulding machines with a mould-cavity base which is inherently rigid and can be moved by appropriate displacement means. This inwards movement prevents a head of meat mass projecting from the uncovered outer side of the mould cavity and being spread out by contact with the closure component. After the mould cavity has been covered by the closure component, the base of the mould cavity can be moved outwards again, if appropriate in order to produce the desired fixing pressure by means of the position of the base. Furthermore, it will be clear that this concept can be applied to all types of moulding machines with mould cavities which move past a filling component, i.e. not only rotating drum type machines but also slide plate machines and turret machines. 
       FIG. 11  shows a cross section through part of a moulding machine, the rest of which is not shown, for example one of the above-described moulding machine of the rotating drum type, for moulding a three-dimensionally moulded product from a mass of foodstuff which is suitable for human consumption, in particular from a mass which consists substantially of pounded (chicken) meat. The part which is shown relates to a drum  2  and a mould  150  which is fixed therein by means of bolts or other attachment means and is made, for example, from metal or rigid plastic, with a mould cavity  151  therein. The mould cavity  151  is delimited by a base  152  and a circumferential wall  153  and is open on the side lying opposite the base  152 . A first passage  154 , which is in communication with one or more first nozzles  155  located in the central area of the base  152 , is associated with the mould  150 . Furthermore, there is a second passage  160  which is in communication with one or more second nozzles  161  in the base  152 . These second nozzles  161  lie in an annular area between the central area of the base, which is provided with the first nozzles, and the circumferential wall  153 , or if appropriate even in the circumferential wall  153 , in the vicinity of the base  152 . The passages  154  and  161  can be selectively connected to a source of air or another gas under pressure or to a vacuum pump or another reduced-pressure source. 
     To prevent contamination of the mould  150  and to avoid adhesion between the meat mass and the mould  150 , there is provision for a flexible membrane  165  to be arranged between the walls of the mould cavity and the portion of meat  166  which is to be introduced into the mould cavity  151 . In this figure, the thickness of the membrane  165  is exaggerated, and the membrane may, for example, be formed by a disposable film or by the elastic belt as described above. If appropriate, the membrane  165  may form part of the mould  150  and may be fixed to the mould  150  in the vicinity of the circumferential edge of the filling opening of the mould cavity  151 . 
     If the membrane  165  is a film as described, for example, with reference to  FIG. 5 , the air which is present in the mould cavity  151  after the film has been placed over the opening of the mould cavity  151  is sucked out via the first and/or second passage  154 ,  161 , so that the film comes to lie taut against walls of the mould cavity  151 . Then, if appropriate at the same time as the mould cavity  151  is evacuated, the portion of meat is introduced into the mould cavity  151 . 
     The above-described design of the mould  150  is also important for releasing the moulded meat product from the mould cavity  151 . In this case, there is provision for a pressurized medium to be fed first to the second passage  160  and thus the nozzles  161  in the vicinity of the circumferential wall  153 , while no medium is being fed to the first nozzle(s)  155 , or even a reduced pressure is maintained at the first nozzle  155 . This ensures that the product  166  is firstly pressed outwards in the area in the vicinity of the circumferential wall of the mould cavity  151  while the product in the centre remains in position. By then feeding a pressurized medium via the first nozzle(s)  155  as well, the whole of the product  166  is removed from the mould  150  and moves uniformly upwards. 
     The membrane may also at the same time serve as (part of) the packaging of the moulded product; for example, it is conceivable for the membrane  170  from  FIG. 12 a    to be placed as a loose element inside the mould and to be held in place temporarily, for example via a vacuum groove running along the circumferential wall of the mould cavity, and to remain around the product as packaging after the product has been moulded. 
     The inventive concept explained with reference to  FIG. 11  can also be realized with a base/wall covering structure for the mould cavity as shown in  FIG. 12 a   . In this design, the base  152  and the wall  153  of the mould cavity are covered by a covering with a flexible part  170 , which covers the wall  153  and an annular area of the base  152  which adjoins the wall, and a stiffer or even hard part  171 , which covers the central part of the base  152 . By then supplying air via passage  160 , the initial movement takes place in that part of the mass  166  which is located along the wall  153 . Then, the centre of the said mass  166 , which is supported by the rigid part  171 , also moves out of the mould cavity  4 . The rigid part may also be made of the same material as the flexible part  170  but may then be cooled and therefore be made more rigid, for example by cooling, for example using cold nitrogen. 
     In a variant, the rigid part  171  of the membrane is absent, and is replaced by a rigid piece of the edible product which is ultimately to be produced on the membrane. 
     The structure shown in  FIG. 12 a    is particularly advantageous for exerting a fixing pressure on the mass  166 , since the said mass  166  is covered on the side of the opening in the mould cavity by a suitable closure component. By then exerting air pressure via passage  154 , the hard disc part  171  presses against the mass, in fact in the manner of a piston, but without the associated disadvantages. 
     In a variant shown in  FIG. 12 b   , the cover comprises flexible film or a flexible membrane  180 , and a part of the base  152  of the mould cavity which is free of the wall  153  is designed as the end face  180  of a moveable disc-like piston  181 . The annular area  182  of the base  152  around the piston  181  lies—in the retracted position of the said piston  181 —further inwards than the end face  180 . Nozzles of air passage  184  are present in the mould  150 , below the piston  181 . If the mass  166  is covered on the side opposite the piston  181  and if it is desired to exert a fixing pressure on the mass  166 , air or some other gas or a liquid can be supplied under pressure, via the air passage  184 , so that the piston  181  is pressed outwards and the mass is placed under pressure. If the product, after the fixing period, is no longer covered, and the moulded product is ejected, pressurized medium can again be supplied via passage  184 , with the result that this pressurized medium emerges from under the piston  181  and initially presses the mass  166  outwards in the annular area, followed by the piston  181 . 
     It will be clear that the mould designs described with reference to  FIGS. 11 and 12   a ,  12   b ,  12   c  may also be applied to all the known and abovementioned types of (meat) moulding machines, i.e. also in machines of the slide-plate and turret type. 
     The abovementioned moulds are all of “self-releasing” design, so that it is not necessary to design the mould in two or more parts which have to be moved apart in order to remove the moulded product from the mould. It will be clear that the inventive concept can also be applied to a mould with a mould cavity which is not of “self-releasing” design and, for example, comprises two mould halves which have to be moved apart in order for the moulded product to be released. Such moulds may also, for example, be placed around the circumference of a drum or accommodated in a turret, which will be explained in more detail with reference to  FIGS. 18 a    and  18   b.    
       FIG. 12 c    shows a mould  190  of particular design which can be used to produce products which are not automatically released. The mould  190  comprises two mould halves  191  and  192 , of which the mutually facing sides, which between them delimit a mould cavity  196 , are at least partially defined by the heads of a large number of pins  193  and  194 , respectively. The pins  193 ,  194  can be moved in their longitudinal direction, so that in this way the shape of the mould cavity  196  can be determined. The mould cavity  196  may be filled on the side  195  and may also be opened on that side, although release may also, if appropriate, take place on the other side. A membrane  197  lies over the heads of the pins  193 ,  194  and may, as described above, be a (packaging) film, for example. 
     The mould  190  can also be used to exert a fixing pressure after the mould cavity  196  has been filled, for example by moving the pins of one of the mould halves slightly towards the other mould half 
     To provide cohesion of the pieces of meat in the mould, local heating may be provided, so that the product becomes dimensionally stable as a result of coagulation. As an alternative, it is possible to freeze the mass in the mould cavity. In the case of these thermal treatments of the mass in the mould cavities, it is deemed advantageous to arrange thermal insulation between the mould cavities. When a meat mass is heated, fat may be released, which fat may facilitate removal of the moulded product from the mould cavity. 
       FIG. 13  shows a perspective view of a moulding device  70  of the “rotating drum type”, for example designed as described above with reference to  FIGS. 4-10 , with an associated filling component  71 . To feed the meat mass to the filling component  71 , an extruder  72  is provided, having an extruder screw  73  which can rotate inside an associated extruder tube  74 . The extruder  72  is fed with meat from a storage container  75 , which meat is pounded by the extruder  72  and is pushed towards the filling component  71 . The consistency and in particular the viscosity of the meat mass coming out of the extruder  72  are of great importance for the operation of filling the mould cavities of the moulding device  70  and for forming the moulded meat products. Therefore, the invention provides for additives to be added to the meat mass in the extruder  72  when necessary, in order to alter the viscosity. Furthermore, additives may be added to the meat mass at the extruder  72 , preferably by means of feed means  76 ,  77  which are connected to the extruder tube  74 . These additives may, for example, be spices, flavourings and colorants, water, egg white, etc., but it is also conceivable for another type of meat to be added. The additives are fed to the extruder tube  74  under pressure. Preferably, the pressure of the meat mass is regulated in the chamber of the filling component  71 , in such a manner that the pressure in that chamber is kept within a predetermined pressure range, for example by regulating the rotational speed of the extruder screw  73 . As an alternative to an extruder screw as shown and described here, it is also conceivable to use a different type of conveying/mixing component for supplying and mixing the mass to the moulding machine. By way of example, a ribbon mixer could be used. 
       FIG. 14  shows a variant embodiment of the device shown in  FIG. 13 , with which it is possible to produce layered products. This figure, in addition to the components which are provided with the same reference numerals as those in  FIG. 13 , also shows a special filling component  141  with two connections, one for the extruder  72  and one for a second extruder  142 , which is only shown in part. In the filling component  141 , each connection is adjoined by an associated system of passages which has branching passages which divide the streams of pounded foodstuff emerging from the extruders  72  and  142  into sub-streams. The passages of each system of passages each end at an associated outlet nozzle. By suitably designing the filling component  141  it is possible, for example, to supply a plurality of alternating, adjacent sub-streams of different masses at the location where the mould cavity moves past the filling component  141  and to place these different masses into the mould cavity. In this way, it is possible, for example, for a product p to comprise a middle strip  145  of a foodstuff delivered by extruder  72  and two outer strips  146 ,  147  of a foodstuff delivered by extruder  142 . The strips  145 - 147  adjoin one another transversely with respect to the direction of rotation of the drum  70 . Obviously, a product may be composed of even more strips and/or even more extruders could be connected to the filling component  141 . 
     It will be clear that if the mould cavities of the drum have their filling opening on the inside, the filling component  141  may also bear against the drum on the inside. 
       FIG. 15 a    shows a variant embodiment of the device according to the invention which makes it possible to produce a product with an internal filling, for example a chicken product with an internal filling of sauce, and/or a layered product. 
     The device  200  has a rotatable drum  202  with mould cavities  204 , the base  205  of which is able to move inwards and outwards, for example by forming the base as a piston which can be moved to and fro. The device  200  comprises a first filling component  206  which, as seen in the direction of rotation of the drum  202 , is in this case located upstream of the highest point of the path of the drum  202 . On reaching the first filling component  206 , the base  205  of the corresponding mould cavity  204  is in a position which is located towards the outside with respect to the final thickness of the product which is to be produced. The filling component  206  is then used to fill the mould cavity  204  with a (meat) mass. Then, the base  205  moves inwards, and a hollow is pressed into the (meat) mass by a hollow-pressing component  210  which is located along the drum  202 . The hollow may be of any desired form, including an annular recess. Then, a portion of filling is placed into the said hollow by means of a filling-feed component  211 . The filling may be liquid, but could also be solid, for example a block of frozen sauce or an edible body. In the case of a solid piece of filling, it would be possible to dispense with the operation of forming the hollow. 
     After the filling has been placed in the hollow, a second layer of the meat mass is placed into the mould cavity  204  with the aid of a second filling component  213  which is located downstream of the first filling component. By introducing meat mass using the second filling component, the filling is completely enclosed between the two layers of meat mass. Furthermore, it is now possible to exert a fixing pressure on the mass in the mould cavity  204 , preferably in one of the ways described above, for example at the location of closure component  214 . Then, the moulded product with the internal filling can be ejected from the mould cavity  204 , during which operation the base  205  is moved outwards. 
     It will be clear that a product composed of a plurality of layers can be formed in each moulding cavity using a device which comprises a plurality of filling components which are arranged one behind the other in the direction of rotation of the drum, with the mould cavities which move past the filling components having a moveable base, which base is then moved in a stepwise manner in order to increase the size of the mould cavity and in order to be able to accommodate a new layer of (meat) mass. This measure could also be combined with a filling component as described with reference to  FIG. 14 , so that various layers can be formed both in the thickness and in the width of the product. 
     In a variant which is not shown, no filling is introduced into the product, but rather two products which are separated from one another by a film or the like are produced in one mould cavity. This is possible by arranging a film over the outside of the mould cavity after it has moved past the first filling component  206 , after which the base of the mould cavity moves inwards, and then a following product is formed on the film by means of the second filling component  213 . As an alternative to film, a loose disc could also be used. 
       FIG. 15 b    shows a moulding device  230  with two drums,  231  and  132  respectively, which are positioned next to one another and are each provided with associated mould cavities  233  and  234  on the outer circumferential surface. The drums  231  and  232  are driven in rotation in opposite directions but at the same circumferential speed, by means of drive means (not shown). Furthermore, the cross-sectional dimensions of the openings of the mould cavities  233  and  234  are identical, so that, given a suitable arrangement of the drums  231  and  232 , it is possible to make two mould cavities  233  and  234  accurately adjoin one another. In this case, the delimiting edges of these two mould cavities bear tightly against one another. To allow the drums to rotate, it is possible for one of the drums to be moved sideways to and fro with respect to the other drum during rotation. As an alternative, the delimiting edges of the mould cavities of one or both drums could be designed in such a manner that they can be compressed resiliently. 
     Each drum  231  and  232  has an associated filling component  235 ,  236 , by means of which meat mass or the like can be introduced into a mould cavity. On the downstream side of each filling component  235 ,  236 , there is an associated closure component  237 ,  238  with dimensions which are such that the component closes off a mould cavity at least while the mould cavity is still in communication with the filling component. In this way, a completely filled mould cavity can be obtained in both drums, with the mass in the mould cavity projecting outwards with respect to the plane running across the delimiting edges of the mould cavity. As the drums  231  and  232  rotate further, the filled mould cavities then come to lie next to one another, with the delimiting edges of these mould cavities adjoining one another in a sealed manner and thus forming a completely closed space. By means of this measure, the mass in this space is compressed with respect to the situation after it has moved past the filling component, so that by means of this compression the mass in the closed space is subjected to a fixing pressure. Obviously, it is also possible to provide additional measures for controlling the fixing pressure, for example the use of film between each of the drums and the mass which is to be fed, and the exertion of a gas pressure between the drums and the film at the time at which the two mould cavities adjoin one another. 
     The fixing pressure produces adhesion between the pieces of meat, after which the meat product p can be removed as a cohesive unit and can be discharged via conveyor device  240 . 
     It will be clear that the device  230 , instead of having drums  231  and  232 , may also be produced with two turrets which run past one another, in which case, for example, the path over which the mould cavities adjoin one another, and therefore over which the fixing pressure prevails, can be extended further. 
       FIGS. 16 a  and 16 b  and 17 a - h    show an alternative moulding device for producing three-dimensional products from foodstuff. This device comprises a stationary central tube  310  which is preferably arranged at the end of an extruder  302 , as can be seen from  FIG. 16 b   . In the central tube  301  there is an opening  303 , through which (meat) mass which has been fed via the interior of the tube  301  can move out of the tube  301 . A ring  305  which can be driven in rotation and is coupled to a drive motor, for example by means of a gear wheel/gear ring transmission  306 , lies around the outside of the tube  301 . 
     The ring  305 , together with the tube  301  which fits inside it, forms two substantially C-shaped chambers  308  and  309  which are located around the tube  301 . These chambers  308 ,  309  each have an associated outlet  310 ,  311 , respectively, leading to the outside of the ring  305 . A stationary cylindrical outer casing  312  with a single opening  313 , which may be aligned with a matching outlet  310 ,  311 , fits around the outside of the rotatable ring  305 . The outer casing  312  is arranged eccentrically with respect to the tube  301 . 
     The chambers  308  and  309  are separated from one another by inwardly projecting lobes  314 ,  315  on the ring  305 , which lobes are designed in such a way that, in the event of rotation of the ring  305 , they continue to bear in a sealing manner against the tube  310 . 
     The opening  303  and the opening  313  are arranged in such a way that, in the event of rotation of the ring  305 , they temporarily come into communication with the same chamber  308  or  309 . 
     This device operates as follows. When the device starts up, the chamber  308  will be filled via opening  303 , this operation taking place for as long as this chamber is in communication with the opening  303  (cf.  FIGS. 17 a -17 c   ). Then, the volume of the chamber  308  becomes ever smaller as a result of the eccentric arrangement of the ring  305  with respect to the tube  301 , until a minimum volume is reached ( FIG. 17 e   ). As a result of this reduction in volume, the mass in the chamber  308  is compressed by a pressure which is independent of the pressure with which the mass has been introduced into the chamber  308  via the opening  303 . When the ring  305  rotates further, the volume of the chamber  308  increases again and, as soon as the chamber  308  reaches the opening  303  again, further mass will enter the chamber  308  adding to the already compressed mass ( FIG. 17 g   ). As soon as the outlet of the chamber  308  then reaches the opening  313  in the outer casing  312  ( FIG. 17 h   ), at that moment mass which flows in via the opening  303  presses a portion of the already compressed mass outwards via the outlet. It will be clear that the same process takes place in chamber  309 . 
     To regulate the pressure with which the mass is compressed, it is possible for the device to be designed in such a manner that the eccentricity can be adjusted within a defined range. 
       FIGS. 18 a  and 18 b    show an embodiment of a moulding device  325  according to the invention in which a mould comprises two mould halves  326  and  327  which can move with respect to one another. The two mould halves  326  and  327  may, for example, be accommodated in a turret which transports the mould halves along a path. In this case, the design may, for example, be such that, in a bend in the path, the two mould halves  326  and  327  are moved away from one another, as in  FIG. 18 b   , and in a straight part of the path bear against one another, so that the mould  328  is then closed. 
     The mould half  326  is provided with a feed tube  329  for feeding the (meat) mass to the mould cavity  328 . In this case, however, in the open position of the mould, a balloon-like membrane  330  is placed in the mould, with its opening connected to the feed tube  329 , so that the mass moves into the balloon  330 . The balloon  330  is preferably made from an elastic plastic material, preferably of a quality which is such that the balloon can be used directly as a packaging material for the moulded products  331 . 
     After the mould has been closed, mass is then introduced into the balloon  330 , so that this balloon adopts the shape of the mould cavity  328 . After the filling has finished, the balloon already exerts a fixing pressure on the mass, but preferably additional measures are provided in order to produce a controllable fixing pressure. For example, a pressure medium can be placed between the mould and the balloon  330  via connecting passage  335 , the pressure of which medium can be regulated in order to control the fixing pressure. 
     When the fixing period has expired, the mould can be opened and the moulded product  331 , which is packaged inside the balloon  330 , can be removed and discharged using discharge means  336 . 
     The method according to the invention is described in claims  1 - 5 , and a number of moulding devices which are suitable for implementing this method are described in the following claims. However, the present invention also relates in part to the moulding devices themselves, independently of the method according to claims  1 - 5 , a fact which could be represented by replacing the current wording “moulding device for carrying out the method according to one of claims  1 ” by “Moulding device for moulding three-dimensional products from a mass of foodstuff which is suitable for human consumption”. Furthermore, it will clear that the present description, with reference to various figures, mentions numerous aspects which can be combined by the person skilled in the art and may, for example, be implemented in a single moulding device. It will be clear that the present application also relates to such combinations and devices.