Freezing of material into blocks

Abstract: The present invention relates to a method and an apparatus for freezing of material into blocks, and to such frozen blocks. The apparatus comprising cooling means (11) and motion means (12) to pass a sheet or belt (13) along said cooling means (11), characterised in that the apparatus (10) further comprises at least one flexible, material receiving mould comprising at least one upwards and downwards open compartment (15), conveying means (16) to convey said mould, along the refrigerating panel (11) on top of the sheet or belt (13) acting as a base in the compartment (15) in at least part of said passage, and bending means (17) to bend said moulds (14) to release the block in the compartment (15).

Description: The present invention relates to an apparatus and a method for freezing material, such as foodstuff, into portions by positioning the material divided into portions on a sheet and passing it over a contact freezing refrigerating panel. The present invention allows freezing of viscous material into portions of controlled shape and size. The present invention also relates to blocks frozen in accordance with the method or by means of the apparatus of the invention. The present invention is especially suitable for freezing viscous foodstuff materials with or without solid pieces. For example, sauce, pieces of vegetables, meat, or mixtures thereof. The invention may advantageously be used for freezing portions from 5 to 200 g, or even bigger portions. A traditional way of freezing food material is by pouring the material into moulds which are then cooled. This is a relatively slow way of freezing due to the very little if any direct contact with the cooling medium. Another disadvantage of this traditional mould is that releasing the frozen material from the mould is difficult due to the increase in size of the material when frozen. It is also known to chill and freeze food material by depositing it onto a sheet and passing the said sheet over a contact freezing surface so as to provide, at least on its lower surface, a frozen crust formation. The contact freezer has the advantage that it provides a fast freezing as a result of the contact between the material to be frozen and the cooling surface, while the thin sheet prevents the material from sticking to the cooling surface. Another way of freezing food material is by depositing it onto a steel belt and cooling it with nitrogen. However, these known freezing methods suffer from the problem of controlling the shape and size of the material to be frozen, and are unsuitable for freezing composite or layered products. When dosing viscous material onto a sheet or belt it will evidently spread resulting in a flat pellet type end product. Furthermore, there is a risk that the separately dosed material will flow into the other doses and thus freeze into bigger lumps. French patent application Nos. 2 260 300 relates to an apparatus for producing individual portions of frozen food material and moulds conceived therefor. The apparatus comprises plastic moulded flexible plates with separate alveoli. The apparatus further comprises a device for removing the material from the mould comprising a reel applying pressure onto the bottom of each alveolus. The closed configuration of the alveoli does not promote an easy removal of the blocks from the mould. Swiss patent document Nos. 261 967 is directed to a moulding apparatus adapted for moulding confectioneries and candies which significantly differs from apparatus for freezing food blocks. In particular, the extraction of the candy pieces when sufficiently hardened, is performed by a stamping member which may cause defects or unwanted marks on the candy surface. GB-A-930 216 relates to an apparatus for the production of sugar-confectionery sweetmeats by the deposition of predetermined quantities of sugar confectionery syrup in a mould in which the material is allowed to set before removal. Therefore, the method is not intended for making frozen blocks from liquid and/or solid food materials. The prior document also relates to improved mould for facilitating removal of the set product from cavities of the mould. The moulds are pivotally mounted between a pair of parallel endless chains. Each pivotally mounted mould comprises a metal bar or plate having a hole which is fitted with lining sleeves of internal cross-sectional contour corresponding to the shape of the required sweet material to be moulded. The mould is made of a material which cannot experience deformation during the removal stage of the product. The mould is simply capable to rotate with respect to the chain loosing the product by gravity. As the product may still be sticky, an ejector mechanism can be necessary to assist ejection of the set confections. Other documents can be viewed to refer to a farther technical background of the invention ; such as FR-A-2 109 383 ; US-A-4 335 147 ; US-A-1 576 019 ; FR-A-750 941 ; EP-A-0 555 166. The present invention overcomes the above described difficulties and provides an apparatus and a method which give the possibility of: Fast and efficient freezing of material into separated portions or blocks of well defined shape and size. A freezing of blocks in a well defined shape and size which gives a good presentation of the final frozen product. Continuous production of blocks of food material. freezing of products comprising layers of different material. Combining material into a layered or composite product of well defined geometry. For example by stepwise filling and freezing of the material in the mould to produce a well defined layered product. Suitability for freezing blocks of ready meals, e.g. 150-200 g or even bigger blocks comprising homogeneous mixed material or composite products. Production of products of homogeneous weight, volume and size, products the metering of which eases the filling of final packages and minimises overfilling of the packages. In the present context "blocks" shall be taken to mean every shape which can be in a mould, e.g. cubes, thin pellets, or units of more complex geometry. Accordingly, in a first aspect the invention provides an apparatus for freezing of material into blocks comprising cooling means and motion means to pass a sheet or belt along said cooling means, characterised in that the apparatus further comprises at least one flexible, material receiving mould comprising at least one upwards and downwards open compartment, conveying means to convey said mould, along said cooling means, on top of the sheet or belt, so that said sheet or belt acts as a base in the compartment, and bending means to bend said compartment of the mould so as to aid to release the block from the compartment. In a preferred embodiment of the invention the cooling means is a refrigerating panel and the material to be frozen is dosed onto a sheet which is moved by the motion means. Advantageously, convection freezing means may be provided e.g. above said refrigerating panel. In an alternative preferred embodiment of the invention the cooling means is nitrogen and a steel belt acts as a base in the compartments. The conveying means may comprise a support or a fixation for the mould or moulds, and means for conveying the said support or fixation such as a conventional motor. In a preferred embodiment of the invention the conveying means comprises a moulding conveyor defining the mould or moulds, i.e. a conveyor belt wherein the moulds are formed. The mould conveyor gives a controlled advancing of the moulds compared with individually advancing freely movable trays or moulds. The precise position of the moulds is favourable during dosing of a product into the moulds. In addition, cleaning or washing of a moulding conveyor belt e.g. continuously, is preferred rather than the cleaning of individual moulds or trays. Advantageously, the moulding conveyor or the path of the moulds are endless. It is preferred that the moulds or moulding conveyor and the sheet material or belt are passed synchronously along the cooling means. This prevents not fully frozen material from escaping through the downwards opening in the compartments in the moulding conveyor. Furthermore, the risk of tearing of the sheet subjected to friction from the relative movement between the mould and the sheet will be reduced. In order to ensure a material does not exit from the downwards openings in the compartments the downwards openings are positioned in close contact with the sheet or belt. In the embodiment of the invention comprising a sheet support for the compartments, for further sealing of the bottom in the compartment when dosing viscous material into the compartment, the moulding conveyor and the sheet is conveniently positioned upon the refrigerating panel. However, at subsequent fillings of additional layers of product this may take place while the sheet and moulding conveyor pass over panels which are or are not refrigerated, and the tight contact is not as crucial. The apparatus is provided with bending means to bend the moulds whether being separate moulds attached to conveyor means or in the form of a moulding conveyor. An adequate release of the blocks in the compartments in the moulds may be obtained by bending the moulds e.g. by letting the moulds pass at least partly around a roller. However, it is preferred that the moulds are also twisted. The bending and twisting means may e.g. be in the form of a mechanical obstruction in the mould's path forcing part of the mould to be lifted above the said obstructions. Alternatively, pistons subjecting the mould to alternating pressures may be employed. It follows that the bending means and the twisting means may be constituted by one and the same means or by separate means. For the release and ejection of at least partly frozen blocks in the compartments, the bending means provides bending and/or twisting means provides twisting of the mould where it is out of contact with the cooling means. In addition the bending means may provide a bending and/or twisting means provide a twisting of the moulds during its passage along or while being exposed to the cooling means. What forms of blocks can be frozen in the moulding conveyor and how easy it is to release the blocks from the moulding conveyor belt depends on the flexibility of the moulding conveyor and the compartments formed therein. The moulding conveyor belt is preferably of flexible and/or elastic material such as plastic e.g. Polyethylene, PVC or Nylon which can withstand repetitive bending and twisting. In order to easily release the blocks from the compartments, the side walls of the compartments are preferably e.g. leaning between the upwards and downwards openings. If the block e.g. is to be ejected from the downwards side of the conveyor the downwards opening is preferably larger than the upwards opening. The apparatus according to the invention may be provided with emptying means for ejecting the blocks from the compartments. This may e.g. be a roller with projections corresponding to the compartments in the mould. If the mould is then trained around the roller the projections will be pressed into the compartments and thus further ease the release of the blocks therefrom. In a special embodiment of the invention the bending means is replaced by means pressing or tapping the blocks out of the compartments. Such means may e.g. be the above described roller with projections. The material in the compartments is either deep frozen or if in bigger blocks possibly only frozen to have a hard outer covering and subsequently deep frozen outside the apparatus according to the invention. Additional cooling means may advantageously be provided e.g. in the form of convection freezing means positioned above or in close relationship with the refrigerating panel. Also liquid nitrogen may be applied for further cooling of the product in the moulds. If the blocks in the compartment are only partly frozen before being ejected subsequent further cooling may e.g. be provided with the above mentioned cooling means. If sheet material is used as a base for the moulding conveyor, it is preferably flexible and able to withstand friction from and relative movement of the moulding conveyor. In addition the sheet should be a good cold transmitter. In a preferred embodiment of the invention the sheet is a film unrolled from one reel and rolled onto another reel after being passed over the refrigerating panel. If the invention is used for the freezing of food material the sheet or film should be of food acceptable material e.g. PE or PVC. which for hygienic reasons do not have to be reused. For such a purpose the sheet or film has a thickness in the range of 10 to 50 micron. Alternatively, the sheet or film could be in an endless band which if desired between each freezing action is cleaned. In a second aspect, the invention relates to a method for freezing material into blocks comprising the steps of moving said material deposited onto a supporting sheet or belt passeing it along cooling means by motion means, said method being characterised in that the material is deposited into at least one upwards and downwards flexible open compartment in a mould and conveyed by conveying means along cooling means carrying the product supporting sheet or belt said supporting sheet or belt acting as a base in the compartments causing the material to freeze at least partly into blocks, and in that said mould is bent and/or twisted by bending means and/or twisting means to release the block from the compartment. Conveniently, the method according to the invention also comprises a step of depositing the material into the compartments in the mould. In a further aspect, the invention relates to blocks frozen in accordance with the above described method wherein the block comprises one or more layers of material. If bigger portions of food material are frozen lumps or whole pieces of meat may be deposited into the compartment and frozen together with viscous foodstuff. The apparatus and method according to the invention will now be described in greater detail with reference to the accompanying drawings by way of an example in which: Fig. 1 is a schematic drawing showing an embodiment of the invention wherein a sheet material is used as base in the compartment and the cooling means comprises a contact freezing plate and a convection freezer. Fig. 1. shows an apparatus comprising cooling means in the form of a contact freezing panel 11, a convection freezer 18 positioned above said panel 11, and motion means 12 to pass a sheet 13 over said panel 11. The sheet in Fig. 1 is a plastic film supplied from a first reel 20 and after its passage over the panel 11 rolled up on second reel 21. The apparatus further comprises a flexible and endless mould conveyor 14 wherein upwards and downwards open compartments 15 are defined. Furthermore, conveying means 16 to convey said mould conveyor 14 along the refrigerating panel is provided. The conveying means 16 and the motion means 12 may comprise by any suitable conventional motor for advancing respectively the sheet and the mould conveyor 14. The endless mould conveyor 14 is guided into close contact with the sheet 13 which at least along the first part of the refrigerating panel 11 acts as a base in the compartment at least until the product in the bottom of the compartments is frozen and hence seals off any escape of the product through the downwards opening in the compartment 15. The product to be frozen is supplied from a reservoir, not shown, and via a distributing channel 22 dosed into the compartments 15 by means of filling nozzles 24. It is preferred that the product is dosed onto the sheet 13 while upon the refrigerating panel 11. Nevertheless, it is possible to dose the product onto the sheet 13 before it reaches the refrigerating panel 11. This does however increase the requirement of close contact between the lower surface of the mould conveyor 14 and the sheet. The apparatus is further provided with bending means 17 in the form of at least one roller shaft to bend the part of the mould conveyor 14 which is trained around it and thus to release the block in the compartment 15. The apparatus 10 according to the invention works in the following way: Conveniently, the product to be frozen is dosed into the compartments 15 in the mould conveyor belt 14 while being positioned upon and with the downwards opening in close contact with the sheet 13 which covers the refrigerating panel 11 and prevents the product escaping from the compartment and from sticking to the panel 11. High viscous products can be dosed into the compartment before the moulds are passed onto the refrigerating panel 11. The mould and the sheet 13 are passed over the panel 11 and the product is at least partly frozen. The mould is subjected to bending and the pressure of the roller 19 with projections which release blocks 23 of frozen product in the compartments 15. The bending may be carried out while the moulds are passed over the refrigerating panel, e.g. by bending the moulding conveyor 14 sidewards. In addition or alternatively twisting means may be provided for the release of the blocks 23 from the moulds. Accordingly, with the apparatus and method according to the invention and as described above a fast and efficient freezing of material into separated portions or blocks of well defined shape and size is achieved.

Claims: Apparatus (10) for freezing of material into blocks comprising cooling means (11) and motion means (12) to pass a sheet or belt (13) along a said cooling means (11), characterised in that the apparatus (10) further comprises : at least one flexible material receiving mould comprising at least one upwards and downwards open compartment (15), conveying means (16) to convey said mould, along said cooling means (11), on top of the sheet or belt (13), so that said sheet or belt acts as a base in the compartment (15), and bending means (17) to bend said compartment (15) of the mould so as to aid to release the block from the compartment (15). Apparatus according to claim 1, wherein said at least one mould consists of a mould conveyor belt (14) having a plurality of flexible open compartments (15). Apparatus according to claim 2, wherein the apparatus further comprises twisting means to twist said mould or moulds. Apparatus according to claim 2 or 3, wherein the mould conveyor belt (14) is endless. Apparatus according to claims 3 or 4, wherein the bending means (17) and/or the twisting means provides bending and/or twisting of the mould conveyor belt (14) where it is out of contact with the cooling means (11). Apparatus according to any of claims 3 or 4, wherein the bending means (17) and /or twisting means provides bending and/or twisting of the mould conveyor belt (14) where it passes along the cooling means (11). Apparatus according to any of claims 2 to 6, wherein the mould conveyor belt (14) is of flexible plastic or rubber. Apparatus according to any of claims 1 to 7, wherein said apparatus further comprises emptying means (19) for ejecting the block from the at least one compartment (15). Apparatus according to claim 8, wherein said emptying means comprises a roller (19) having projections corresponding to the compartments in the mould. Apparatus according to any of claims 1 to 9, wherein the cooling means is a refrigerating panel (11) arranged so that the motion means (12) moves the sheet or belt (13) over said refrigerating panel (11). Apparatus according to claim 10, wherein the apparatus further comprises convection freezing means (18) positioned above the refrigerating panel (11). Apparatus according to claims 10 or 11, wherein the cooling means comprises nitrogen, and a steel belt acts as a base of the compartment (15). Apparatus according to any of claims 10 to 12, wherein the sheet (13) is film unrolled from one reel and rolled onto another reel after being passed over the refrigerating panel (11). Apparatus according to claim 13, wherein the film is made of a food acceptable material having a thickness in the range of 10 to 50 microns. Method for freezing material into blocks comprising the steps of moving said material deposited onto a supporting sheet or belt (13) passing it along cooling means (11) by motion means (12), said method being characterised in that the material is deposited into at least one upwards and downwards flexible open compartment (15) in a mould and conveyed by conveying means (16) along a cooling means (11) carrying the product supporting sheet or belt (13); said supporting sheet or belt acting as a base of the compartment (15) causing the material to freeze at least partly into blocks, and in that said mould is bent and/or twisted by bending means (17) and/or twisting means to release the block from the compartment (15). Method according to claim 15, wherein the motion means (12) and the conveying means (16) run synchronously. Method according to claims 15 or 16, wherein more than one layer of material are deposited into said compartment (15).

Inventors: ANDERSSON BO, ANDERSSON, BO
Applicants: NESTLE SA, SOCIETE DES PRODUITS NESTLE S.A.
Application year: 1995
Main classification: A23L3
IPC codes: A23L3, A23G3