Method and apparatus for forming and hermetically sealing slices of processed cheese

Abstract: An apparatus and method are provided for forming a hermetically sealed package for a slice of a food item. A web of thermoplastic material is first formed into a tubular arrangement with a hermetic longitudinal seal. To form the tubular arrangement, means are provided for folding a continuous web of thermoplastic material into V-folded condition and for continuously forming a hermetic seal along the open longitudinal edge of the V-folded web. The hermetic seal is formed between the inner surfaces of the front and rear faces of the web to define a tubular web member. The food item which has been formed into a soft mass, is then inserted into the tubular member and the tubular member is flattened to form a thin film tube. Means are provided for forming a hermetically sealed cross-seal which are disposed substantially transverse to the longitudinal forward moving direction of the web.

Description: BACKGROUND OF THE INVENTION The present invention relates generally to an apparatus and method for packaging processed cheese and more particularly to an apparatus and process for packaging processed cheese in hermetically sealed individual slices. Various methods and apparatus have been proposed and utilized for the manufacture and packaging of individual slices of food items such as cheese. Although the available apparatus and methods are suitable for the packaging of individual slices, they are not without disadvantages. Typically, the package for the individual slices is formed from a continuous film or web of a thermoplastic material. The web is first folded in V-folded condition. As used herein, the term V-folded condition refers to a length of material which has been folded over onto itself so as to form what may subsequently be identified as a front sheet and a rear sheet which are joined by the fold at the bottom, so as to approximate the letter "V" in cross section. The web is typically folded such that the rear sheet is longer than the front sheet to define a flap section in the rear sheet, which extends beyond the top edge of the front sheet. The flap section is typically folded over onto the front sheet to form a tubular web. After the flap is folded over on the front sheet, a tubular web is defined. The processed cheese is then inserted into the tube and the web and cheese are flattened. Subsequently cross-seals are formed along the longitudinal length of the tubular web at predetermined intervals. After the tube is cross-sealed it is severed along the cross-seals in order to produce the individually wrapped slices of cheese. Several processes presently exist for providing the transverse or cross seal. In one commonly used method, the cross-seals are formed by subjecting the flattened web (with the inserted cheese) to pressure, at the desired location, to form the transverse cross seal. The pressure is applied such that an ultra thin layer or film of cheese is left in the transverse sealing section. The ultra thin layer or film of cheese acts as an adhesive to seal the two layers of the plastic web together. After this "cheese" seal has been formed, the web is severed at the sealed sections to define individual slices of cheese. Although the "cheese" seal provides an adequate seal for the individual slices of cheese, the shelf life of the cheese product after it is packaged is not as long as would be desirable. This is due to the fact that the cheese seal is a relatively weak seal which will eventually deteriorate and which allows air to enter into the slices under ordinary atmospheric conditions. The slices will soon dry out or spoil. Other methods of providing a transverse cross-seal have also been disclosed. For example, U.S. Patent No. 4,586,317 (Bussell) discloses an arrangement for forming a seal in packaging material (such as processed cheese) which utilizes a sealing element having a finite number of small channels in the surface. The packaging film is co-extruded or laminated to include an inner sealing layer of relatively low thermal plastic melt temperature and an outer layer which does not melt under sealing conditions. The tube is heated and compressed transversely by the sealing elements thereby sealing the internal layers of the packaging film together. Although the apparatus and method disclosed in this patent provide a suitable cross-seal, the finished product suffers from the same disadvantages that are described above. Since the longitudinal seal is formed by providing a flap in the V-folded condition web and simply overlapping the flap with the upper surface of the front sheet of the web, a poor seal is formed. Thus, air and other atmospheric products will enter into the wrapped slices of cheese, reducing the shelf life of the product. Therefore it would be desirable to provide an individual slice of cheese which is wrapped in a package which is hermetically sealed on all sides. To accomplish this, a hermetic seal must be formed along the longitudinal edge of the web as well as along the transverse or cross-seals. A hermetically sealed package would have several advantages. For example, a hermetically sealed slice would permit immersion for cooling and sanitizing. Further, a hermetically sealed slice is essential to aseptic packaging. DE-A-3841945 relates to a device for the packaging of a product in flexible envelopments of plastic wherein the volume of the packaged product is maintained. Said device provides the longitudinal seal and cross-seals in a continuous process. However, although DE-A-3 841 945 shows heat sealing means for the cross-seals, it does not mention whether these seals are hermetic or not. Therefore, in view of the above, it is an object of the present invention to provide an apparatus and a method for producing individual slices of processed cheese, which are hermetically packaged. It is a further object of the present invention to provide an apparatus and method for providing a continuous and efficient arrangement for forming hermetic seals along all of the edges of the packaging web. Accordingly, the present invention provides a process as defined in claim 1 for packaging processed cheese wrapped in hermetically sealed individual slices. The present invention also provides an apparatus as defined in claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices. In particular, the present invention according to claims 1 and 8 differs from the disclosure of DE-A-3841945 in that the cross-seals are hermetic and in the manner in which the web of thermoplastic material is arranged in folded condition. The present invention according to claim 1 also differs from the disclosure of DE-A-3841945 in that the web is cooled after the web has been flattened and before the cross-seals are formed. In a preferred embodiment of the invention the means for forming the longitudinal seal include a pair of stationery plates with opposed undulating surfaces. The plates are arranged such that a fixed predetermined distance is defined between the undulating surfaces of the plates. The plates are heated and the web is passed through the space between the two plates. As the web moves through the plates, the undulating surfaces alternatively force the front and rear faces of the web into intimate contact with each other to thereby form a hermetic longitudinal seal without clamping the film between the surfaces. Additional objects, advantages and novel features of the invention will be set forth in part in the description which follows, and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention. The objects and advantages of the invention may be obtained by means of the combinations particularly pointed out in the appended claims. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic representation of a preferred embodiment of the apparatus and method of the present invention including the longitudinal sealer and the cross sealer FIG. 2 illustrates a preferred embodiment of a slice of cheese which has been sealed with the process and apparatus of the present invention (with the flap folded over). FIG. 3 illustrates the slice of cheese illustrated in FIG. 2 with the flap unfolded. FIG. 4 is an illustration of a preferred embodiment the longitudinal sealer and flattening means of the present invention. FIG. 5 is a schematic representation of the cross sealer illustrated in FIG. 1. FIG. 6 is an illustration of a preferred embodiment of the longitudinal sealer of the present invention. FIG. 7 illustrates an enlarged side view of a section of the cross sealing arrangement illustrated in Fig. 1. DETAILED DESCRIPTION OF THE PRESENTLY PREFERRED EMBODIMENTS Reference will now be made to the drawings wherein like elements are referred to with like reference numerals throughout the various drawings. Referring specifically to Fig. 1, a preferred embodiment of the arrangement and process of the present invention including the longitudinal sealer and cross sealer. Cheese is first processed, in a manner known in the art, by cheese processing means 10. The processed cheese is then transferred, in a known manner, from the cheese processing means 10 into a fill tube arrangement 12 which is used to insert the processed cheese into a tubular web made of thermoplastic material. In more detail, the tubular web of thermoplastic material is formed by providing a continuous film or web of thermoplastic material and folding the web into V-folded condition, in a manner known in the art. After the web of thermoplastic material has been folded into the V-folded condition, a longitudinal seal is formed at a sealing station 20 (in a manner described in more detail below). Nip rollers 16 are provided to secure the seal and continuously pull the web of thermoplastic material. After the longitudinal seal is formed at the sealing station 20 and leaves the nip rolls 16, the cheese is inserted by means of the fill tube 12 into the tubular web. The web and cheese are then passed to a flattening station 22 (also described in more detail below). At the flattening station 22, the tubular web with the cheese is flattened to form a continuous web or slice of cheese. After the web has been flattened and formed into the film, the web is then passed through a cooling station 14. In one preferred embodiment, the cooling station 14 comprises a tank or container for holding a cooling liquid, such as water. In this embodiment, the cooling station 14 may include a plurality of rollers such that the web and cheese are passed through the tank in a winding fashion. Preferably the cooling station 14 is configured such that the web with the cheese passes through the cooling water for approximately 20 seconds with the water being at between 0°C (32°F) and 10°C (50°F). This will take the cheese which usually starts off at a temperature of between 77°C (170°F) and 100°C (180°F) and cool the cheese down to approximately 10°C (50°F) at the exiting end of the cooling station 14. Preferably, the cooling station includes a roller which is over driven to provide means for keeping the web taut. The cooling station may also include scrapers and/or air-blowers (not shown) to dry the web as it exits from the cooling station 14. It will be recognized by those skilled in the art that other suitable cooling means may also be used. After leaving the cooling station 14, the web is conveyed, preferably by a pair of driven feed belts 39, to the station which forms the cross seals. A loop control means and tensioning means 41 may be provided. The transverse or cross sealing station 40 includes a first member 42 with a plurality of heated jaws 46 and an opposed bottom member 44 with jaws 50 with opposed engaging surfaces. The cross sealing station 40 provides a hermetic seal 102 transverse to the longitudinal or forward moving direction of the web. The web now includes a plurality of slices of cheese 100 which are hermetically sealed. The cross sealing station 40 is described in more detail below. THE LONG SEALER Referring now specifically to Figs. 4 and 6 a preferred embodiment of the longitudinal sealing arrangement 20 and the flattening arrangement 22 are illustrated. The preferred embodiment of the longitudinal or long sealing arrangement 20 provides a novel and advantageous apparatus and process for forming the longitudinal seal in the web without stopping the web in an intermittent fashion. The sealing station 20 includes a pair of stationary heated plates 24, 25. Each plate includes an undulating surface which forms an important part of the longitudinal sealer 20. The undulating surfaces of the plates 24, 25 are opposed and the plates 24, 25 are disposed such that a fixed gap or distance exists between the opposed undulating surfaces. The gap between the undulating surfaces of the plates 24, 25 is fixed such that as the front and rear sheets of the open longitudinal end of the web are conveyed between the undulating surfaces, the front and rear sheets of the web are forced into intimate contact with each other. In a preferred embodiment the gap between the undulating surfaces is tapered having a wider gap at the top than the bottom with an average gap distance of approximately 1,6 mm (1/16 of an inch). Means are provided for heating the two plates to a temperature sufficient to form a longitudinal hermetic seal as the web is conveyed between the two plates 24 and 25 without physically clamping the two surfaces together. The heating may be provided by any suitable heating means, for example, an electric heater 26 which is inserted longitudinally through an aperture 23 in each plate 24, 25. The plates are heated to a temperature sufficient to form a hermetic seal between the two sheets of the web, for example, the plates may be heated to a temperature of approximately 127°C (260°F). Nip rollers 16 are provided after the sealing plates station 20 to secure the seal and pull the web through the longitudinal sealer. In a preferred embodiment, the fill tube 12 extends down into the web such that the exiting end of the fill tube 12 is disposed after the nip rollers 16. In this manner, the cheese is inserted into the web after the longitudinal seal has been formed and a tube has been defined. In a preferred embodiment, a bubble control element 28 is disposed before the flattening station 22. The bubble control unit 28 functions to determine the amount of cheese which is being inserted into the web. In this manner, the flow of cheese may be controlled as appropriate for the speed of the web and the desired thickness and weight of the slice. After the cheese is inserted into the tubular web, the tubular web is conveyed to a flattening station 22. The flattening station 22 includes a first or upper set of juxtaposed rollers 32, a lower set of juxtaposed rollers 34, and a pair of opposed belts 30. Each belt 30 is disposed around one set of rollers 32, 34. As the web with the cheese inserted therein passes between the two belts, the cheese is flattened to form a web comprising the tubular thermoplastic film and a continuous slice of cheese. Means 36 are provided in the flattening station 22 for adjusting the distance between the belts 30 to control the thickness of the web of tubular thermoplastic material and cheese. As illustrated in Fig. 3, the web is formed into a tubular section with a hermetically sealed longitudinal seal 106. Preferably, the web is sealed along the top longitudinal edge of the front face of the web such that a flap portion 104 is defined as illustrated in Fig. 3. After the longitudinal seal 106 is formed, the web is conveyed through the cooling station 14, as described above, and then the flap 104 is folded over onto the front face of the web as illustrated in Fig. 2. The flap may be folded over in a manner known in the art before the web reaches the cross-sealing station 40. Preferably, the flap 104 is partially sealed at the cross seal sections to the front face of the web at the cross sealing station 40. THE CROSS SEALING STATION Referring now specifically to Figs. 5 and 7, a preferred embodiment of the cross-sealing arrangement is disclosed. The cross-sealing arrangement includes an upper sealing member 42 and a lower sealing member 44, with each of the sealing members including a plurality of opposed jaws or cleats 46 and 50 respectively. As best illustrated in Fig. 7, the sealing members 42 and 44 are arranged such that as the web is conveyed through the sealing station 40 between the upper cleat 46 and the engaging lower cleat 50 the top and bottom layers of the film web are merged together in the desired cross sealing section. The cleats 46 of the upper member 42 are heated to the sealing temperature, in a manner known in the art. For example, the top cleat 46 may be heated by an electrical heater and brush arrangement. The cleats 46 and 50 may be made of any suitable material such as aluminum. The top cleat 46 preferably includes a removable section 48. The engaging bottom cleat 50 also preferably includes a removable section 45, which is made of a softer material than the top mating section 48 of the cleat 46. For example, the removable section 48 of the top cleat 46 may be made of a metallic material such as aluminum and the removable section 45 of the lower cleat 50 may be made of a resilient material such as polyurethane. For purposes of quality control and to achieve uniformity in the cross seals, each of the heated cleats 46 includes a thermostat 54 which controls the temperature of each individual cleat. Therefore the temperature of each cleat can be adjusted separately. Means are provided for urging the two opposed cleats to engage the web of cheese as it is conveyed through the sealing station 40. As illustrated in the figures, in the preferred embodiment, the means for urging the cleat together comprises a track and chain arrangement. Each of the cleats is attached to a chain arrangement which rides on a track 56, 58. The chain arrangement, illustrated best in Fig. 7, includes sections of chain including rollers 52 and 53 which are attached at spaced intervals to the links of the respective chain. The rollers 52, 53 ride on elongated circular tracks 56, 58, respectively. The elongated circular tracks 56, 58 are disposed such that the cleats 46 and 50 ride in engaging relationship ford a predetermined interval (discussed in more detail below). Preferably the web of cheese in the tubular film is conveyed through the opposed jaws 46, 50 of the sealing members 42, 44 such that a hermetic seal is formed between the two inner layers of the web material. More preferably, the seal is formed such that when after the seal has been made and the package is pulled apart at the seal, the seal will break. This is opposed to the seals which are presently made wherein after the seal has been formed and the package is pulled apart, the seal is broken by delamination, that is, by breaking the bond between the top non-sealing layer of and the inner or sealing layer of the sheet of the web. This preferred packaging arrangement is achieved by proper selection of the thermoplastic material. The material comprises a polypropylene layer coextruded with a polyethylene sealant layer with an intermediate adhesive layer. In a preferred embodiment, the sealing temperature is between 127°C (260°F) and 138°C (280°F) and the jaws travel with the web from the first point of engagement to the point of disengagement for approximately one second. The pressure exerted between the two opposing jaws on the sealing section 106 is such that substantially all of the cheese is removed from between the two layers of the thermoplastic web material in the cross-sealed areas. Suitable means are provided for driving the two chain arrangements in the sealing members 42 and 44. The slices of cheese are defined in the section between the jaws. Preferably, the sealing section of the jaws 46 and 50 are such that the cross seal 102 between adjacent cheese slices 100 is approximately 6 mm (1/4 of an inch). The cleats 46, 50 are spaced in their respective chains such that the distance from the beginning of one slice to the beginning of the next slice (including the cross-seal sections 102) is approximately 90 mm (3-1/2 inches). This arrangement allows for high speed production of the individual slices of cheese 100. Since the heating cleats 46 and the mating 50 ride or move along with the cross seal for a fixed period of time, the web may be continuously moved at a relatively fast pace providing a rapid production rate. For example, the web may be moved at approximately 1,5 m/s (300 feet/minute) or such that over approximately 1,000 slices are produced per minute. Therefore, the packaging system of the present invention provide a means for hermetically packaging individual slices of cheese at an efficient and rapid production rate. The sealing arrangement provided by the present invention provides a hermetic seal along the longitudinal edge of the web. After the cheese is inserted in the tubular web ,hermetically sealed cross seals are formed. This arrangement provides a hermetically sealed package of cheese which will have a substantially longer shelf life than the presently available sliced cheese products. Additionally, the longitudinal seal and the cross seals are provided in a manner which permits continuous movement of the web without the intermittent action of some presently available sealing systems. The slice which is produced and packaged according to the present invention provides a preferred final packaged product. The seal is formed between the two inner layers of the low thermal melt material such that the seal is broken when the packaging materials are pulled apart to open the individual slice. Unlike presently available packages, wherein the sealing layer is delaminated from the top layer of the packaging material and when the package is opened a rough tear is made which leads to "stringing". With the package of the present invention, the bond is broken between the two sealing layers of polyethylene and a nice clean opening is provided which eliminate the stringing problem. Additionally, since the polyethylene is used as the sealing layer, the packaging material is easily released from the processed cheese. This obviates the need for items such as a sheer pump to process the cheese so as to have a less cohesive texture and provide a better release. The process and apparatus of the present invention also permit the top layer of the packaging material to be made of a polypropylene material. This is particularly advantageous since polypropylene is less expensive than presently used materials such as MYLAR (registered trade mark). The foregoing description of the preferred embodiments of the present invention has been presented for purposes of illustration and description. The described embodiments are not intended to be exhaustive or to limit the invention to the precise form disclosed. Obviously many modifications and variations are possible in light of the above teachings. The embodiments which were described were chosen in order to best explain the principles of the invention and its practical applications. It is intended that the scope of the invention be defined by the following claims, including all equivalents.

Claims: A process for packaging processed cheese wrapped in hermetically sealed individual slices (100), comprising the steps of: forming processed cheese into a soft mass; providing a web of polypropylene material, arranging the web of polypropylene material to have a front sheet and a rear sheet in folded condition, and wherein the front and rear sheets each have an outer surface and an inner polyethylene sealant layer, and wherein the web in folded condition has a folded longitudinal first edge and an open longitudinal second edge; moving the web continuously in a forward direction; conveying the web in folded condition to a longitudinal sealing station; forming a longitudinal hermetic seal (106) along the longitudinal second edge of the web, the longitudinal hermetic seal (106) being formed between the inner polyethylene sealant layer on the front sheet of the web and the inner polyethylene sealant layer on the rear sheet of the web so as to form a tubular web of plastic; inserting the soft mass processed cheese into the tubular web of plastic; moving the web continuously in a forward direction; continuously flattening the web with the inserted processed cheese such that a continuous slice (100) of the processed cheese is formed between front and rear sheet of the plastic web; after the web has been flattened and during continuous forward movement of the web, urging opposing portions of the front and rear sheets of the web into intimate contact with each other at a plurality of cross-sealing zones extending continuously between the first and second longitudinal edges of the web, the opposing portions of the front and rear sheets of the web being urged together at the cross-sealing zones at a pressure sufficient to maintain intimate contact between them and to remove substantially all of the cheese from the cross-sealing zones; applying heat to the cross-sealing zones in a conductive manner for an amount of time, and at a sufficient temperature to form hermetic cross-seals (102) extending continuously between the first and second longitudinal edges of the folded web; the folded longitudinal first edge; the hermetically sealed longitudinal second edge, and the hermetic cross-seals (102) thereby providing the slice of processed cheese entirely enclosed within a hermetically sealed package, wherein the process further comprises the step of cooling the web after the web has been flattened and before the cross-seals (102) are formed, and wherein the longitudinal seal and the cross-seals can be opened by breaking the bond between the two sealant layers of polyethylene. The process of Claim 1 for packaging processed cheese wrapped into hermetically sealed individual slices (100), the step of forming a longitudinal hermetic seal (106) further comprising the steps of: arranging a pair of plates (24,25) having opposed undulating surfaces with a predetermined fixed space between the opposed surfaces of the plates, the plates defining a longitudinal sealing station (20); conveying the tubular web to the longitudinal sealing station (20); introducing the open longitudinal side of the web into the space between the undulating surfaces of the plates; heating the plates (24,25) to a temperature sufficient to hermetically seal the front and rear sheets of the web together; and continuously moving the web between the plates (24,25) while maintaining the predetermined fixed space between the undulating surfaces of the plates (24,25) such that the front and rear sheets are brought into contact and a longitudinal hermetic seal (106) is formed along the open longitudinal side of the web. The process of Claim 1 for packaging processed cheese wrapped in hermetically sealed individual slices (100), the step of forming the longitudinal hermetic seal (106) along the open longitudinal side of the web including the step of forming this longitudinal seal in a continuous manner. The process of Claim 1 for packaging processed cheese wrapped in hermetically sealed individual slices (100), the step of forming the hermetically sealed cross-seals (102) further comprising the steps of: arranging a first endless chain (56) including a plurality of a first series of sealing members (44) disposed thereon and a second endless chain (58) including a plurality of a second series of sealing members (42) disposed thereon such that the first and second series of sealing members (44,42) are opposed and ride in aligned relationship for a fixed distance; introducing the flattened web between the sealing members (44,42) on the first and second endless chains (56,58); applying pressure to the sealing members (44,42), while the sealing members on the first and second endless chains (56,58) are in aligned relationship, to urge the opposed sealing members (44,42) towards each other such that the front and rear sheets of the web are urged together; applying heat to at least either the first or second series of sealing members (44,42), the applied heat being sufficient to heat the sealing members (44,42) to a temperature sufficient to seal the top and bottom layers of the plastic web at the applied pressure; and moving the sealing members (44,42) in the aligned position at a sufficient speed for the top and bottom sheets of the web to form a hermetic seal at the cross-seals (102) at the applied pressure and heat. The process of Claim 1 for packaging processed cheese wrapped in hermetically sealed individual slices (100), further comprising the step of controlling the flow of the processed cheese by varying the web speed. The process of Claim 1 for packaging processed cheese wrapped in hermetically sealed individual slices (100), wherein an introducer (12) forms cheese into a sort mass. The process of claim 1 for packaging processed cheese wherein the step of forming a longitudinal hermetic seal includes the application of heat in a conductive manner to the web. An apparatus for packaging processed cheese wrapped in hermetically sealed individual slices (100), comprising: a food former providing processed cheese into a soft mass; a device for folding a continuous web of polypropylene material into folded condition, the folded web including a front sheet and a rear sheet joined by a fold at a bottom longitudinal edge, and having an open top longitudinal edge, the front sheet and the rear sheet each having an outer layer and an inner polyethylene sealant layer; a longitudinal sealing station (20) including a positioner positioning the front sheet and the rear sheet such that, at the open top longitudinal edge of the web, the inner polyethylene sealant layer of the front sheet faces the inner polyethylene sealant layer of the rear sheet, and a longitudinal sealer forming a longitudinal hermetic seal as the web is continuously moved, the longitudinal hermetic seal extending continuously along the top longitudinal edge of the web and joining the inner polyethylene sealant layers of the front and rear sheets of the web, thereby defining a continuous tubular web of plastic material; a cheese introducer for inserting the processed cheese into the continuous tubular web of plastic material; a flattening device (30) continuously flattening the tubular web with the inserted processed cheese inside the web such that a continuous slice (100) of the processed cheese is defined between the front sheet and the rear sheet of the web; a cross-sealing station (40) disposed downstream of the longitudinal sealing station (20), the cross-sealing station (40) including opposing pairs of heated cleats (46,50) arranged to receive the web between the cleats (46,50), the cleats (46,50) applying sufficient pressure at cross-sealing zones to remove substantially all of the processed cheese between the front and rear sheets of the flattened web at the cross-sealing zones, the cross-sealing zones extending continuously from the bottom longitudinal edge to the top longitudinal edge of the folded web, and the cleats (46,50) applying heat conductively to the web at the cross-sealing zones as the web is continuously moved, wherein the heat is applied to the cross-sealing zones for an amount of time sufficient to hermetically seal the inner sealant layers of the front and rear sheets together at cross-sealing zones to thereby provide a hermetically sealed package (100), and wherein the longitudinal seal and the cross-seals can be opened by breaking the bond between the two sealant layers of polyethylene. The apparatus of claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), further comprising a drive (39) continuously conveying the web to the longitudinal sealing and cross-sealing stations (20,40). The apparatus of claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), further comprising a cooling station (14) disposed downstream of the flattening device (30) but upstream of the cross-sealing station (40) for cooling the web after the web has been flattened and before the cross-seals (102) are formed. The apparatus of Claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), the longitudinal sealer further comprising: a pair of fixed plates (24,25), each having an undulating surface, the plates disposed such that the plates have opposed undulating surfaces with a predetermined fixed space between the opposed surfaces of the plates; a heat applicator for applying conductive heat to the plates (26) at a temperatures sufficient to form a hermetic seal between the front and rear sheets of the web; and rollers (16) for continuously conveying the web through the space between the plates such that the front and rear sheets are brought into contact and hermetically sealed together along the second longitudinal side (106) of the web. The apparatus of Claim 11 for packaging processed cheese wrapped in hermetically sealed individual slices (100), wherein the space between the plates (24,25) is tapered, and the tapered space including a wider gap at the top of the plates than at the bottom of the plates. The apparatus of Claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), wherein the the first sealing members (42) include a metallic material and the second sealing members (44) include a non-metallic, resilient material. The apparatus of Claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), the first and second sealing members (44,42) further comprising a corresponding first and second series of cleats (46,50), the sealing members being arranged to receive the web between the cleats (46,50), and the cleats (46,50) applying pressure at a plurality of cross-sealing zones extending transverse to the first and second longitudinal edges, the pressure being sufficient to remove substantially all of the processed cheese between the front and rear sheets of the flattened web at the cross-sealing zones, and at least a portion of the cleats (46,50) also applying heat conductively to said web at the cross-sealing zones as the web is continuously moved, wherein the heat is applied to the cross-sealing zones for an amount of time sufficient to form hermetic cross-seals (102) in which the inner layers of the front and rear sheets are sealed together at the cross-sealing zones. The apparatus of Claim 14 for packaging processed cheese wrapped in hermetically sealed individual slices (100), each of the first and second series of cleats (46,50) further comprising corresponding first (48) and second (45) removeable sections, the first removeable section (48) of the first series of cleat (46) being composed of a metallic material and the second removeable section (45) of the second series of cleat (50) being composed of a resilient material. The apparatus of Claim 14 for packaging processed cheese wrapped in hermetically sealed individual slices (100), wherein either the first (46) or the second (50) series of cleats is heated, and further comprising thermostat controls (54) associated with the heated cleats for selectively controlling the temperature of the heated cleats. The apparatus of Claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), further comprising a selective adjustor (28) for controlling the amount of the processed cheese inserted into the tubular web. The apparatus of Claim 8 for packaging processed cheese wrapped in hermetically sealed individual slices (100), wherein the plastic material includes a polypropylene layer coextruded with a polyethylene sealant layer.

Inventors: BRZEZINSKI EDWARD A, MATHARANI MICHAEL A, MELI VINCENT A, SHAFT DAVID L, URMANSKI JAMES L, BRZEZINSKI, EDWARD A., MATHARANI, MICHAEL A., MELI, VINCENT A., SHAFT, DAVID L., URMANSKI, JAMES L.
Applicants: SCHREIBER FOODS INC, SCHREIBER FOODS INC.
Application year: 1992
Main classification: B65B25
IPC codes: B65B25, B65B9