GB2391323A

GB2391323A - Weighing assembly for food items conveyed in parallel

Info

Publication number: GB2391323A
Application number: GB0217397A
Authority: GB
Inventors: Jeremy Robin John Bagley; Ian George Batt
Original assignee: United Biscuits Ltd
Current assignee: United Biscuits Ltd
Priority date: 2002-07-26
Filing date: 2002-07-26
Publication date: 2004-02-04
Also published as: GB0217397D0

Abstract

A weighing conveyor assembly WCA1 (19 fig 1) separately weighs, at a given time, each parallel portion of a stream of food items. There are preferably at least 4 parallel stream portions extending in the direction of flow, each being arranged to convey at least one lane of items such as moulded dough pieces for biscuits. The assembly is an element of a processing apparatus which may include other conveyor bands (6,15,16,17,18 fig 1) a moulder roll (1a fig 1), an oven (2 fig 1), a position adjusting machine (14 fig 1) , a fondant pickup station (3 fig 1), a chocolate enrober station (4 fig 1), further weighing stations (20,21,22 fig 1) and a packaging station (5 fig 1). The weighing conveyor WCA 1 typically comprises 4 weighing decks WD 1-4 comprising parallel bands mounted on a load cell L1-4. Weight related data is sent to a processor, which preferably calculates a mean item weight for each longitudinal portion. Results can be used in automatically adjusting moulder settings and item alignment.

Description

239 1 323

Improvements in and relating to food processing The invention relates to food processing Food processing oRen involves transporting a multiplicity of individual food items in a stream on one or more conveyors towards, and away from, one or more 5 processing stations, the conveyors and stations often being referred to together as a food processing "line".

In the manufacture of baked food items from dough, for example, individual dough pieces are conveyed on one or more conveyors in a stream towards and away from an oven. The food items of the stream are generally arranged on the or each 10 conveyor in a single layer and in a pattern of rows stretching across the conveyor with predetermined gaps between the food items of each row and predetermined gaps between adjacent rows. The rows may be arranged so that the food items of each row are exactly aligned with the food items of adjacent rows, or each row of food items may be offset from its adjacent rows in order to accommodate as many food 15 items as possible on the conveyor at any one time while still maintaining necessary gaps between them. Although the exact position of an individual food item relative to the others may vary or be adjusted during processing, for example, when the food items are transferred onto conveyors running at different speeds or the pattern of rows is adjusted from offset to aligned, each food item generally tends to stay in the same 20 overall position relative to the other food items of the stream as it travels along the line so that a food item on the edge of one of the conveyors will tend to stay on the edge of the next conveyor, and a food item in the middle of the conveyor will also stay in the middle of the next conveyor.

One of the final steps in the processing line may involve transporting the

finished food items to a packaging station which might, for example, comprise four packaging machines functioning in parallel, each accepting food items from a given portion of the stream of food items as they arrive at the packaging station. If there are localised variations in weight of the food items across the stream' for example, a 5 tendency for food items in the middle of the stream to be lighter than those at the edges, then the packages produced by one of more of the packaging machines may be lighter than others. In order to avoid underweight packages, the other packaging machines must produce overweight packages.

The invention provides food processing apparatus comprising a weighing 10 conveyor assembly and a data processor, the weighing conveyor assembly being arranged to convey a multiplicity of food items at any given time arranged in a stream along a path, food items being continuously supplied to the weighing conveyor assembly, conveyed by it in the said stream along the said path and then discharged from it, in operation, the multiplicity of food items of the stream being in a pattern that 15 extends longitudinally in the direction of travel along the path and transversely to the said direction, the weighing conveyor assembly being arranged to weigh the food items being conveyed at a given time in each of a plurality of longitudinally-extending portions of the path, the said portions extending substantially parallel to each other, and the weighing conveyor also being arranged to send data dependent on the weight 20 of the food items being conveyed at the said given time in each of the said portions to the data processor, the data processor being arranged to give an output that represents a mean weight of individual food items conveyed at the said given time in each of the said portions of the path.

The invention also provides a food processing method in which a weighing

conveyor assembly conveys a multiplicity of food items arranged in a stream along a path, the food items being continuously supplied to the weighing conveyor assembly, conveyed by it in the said stream along the said path and then discharged from it, the multiplicity of food items of the stream being in pattern that extends longitudinally in 5 the direction of travel along the path and transversely to the said direction, the weighing conveyor assembly weighing the food items being conveyed at a given time in each of a plurality of longitudinally-extending portions of the path, the said portions extending substantially parallel to each other, and the weighing conveyor sending data dependent on the weight of the food items being conveyed at the said given time in 10 each of the said portions to a data processor, the data processor giving an output that represents a mean weight of individual food items conveyed at the said given time in each of the said portions of the path.

The apparatus and method of the invention enable the mean weight of individual food items being conveyed in parallel longitudinally-extending portions of I S the path to be monitored, and any variation between the means weights of the food items being conveyed in the different portions across the path to be detected.

The said longitudinally-extending portions of the path may comprise a portion extending along, or adjacent to, an edge of the path, or portions extending along, or adjacent to, each edge of the path, and/or one or more other portions, for example, a 20 central portion. In certain circumstances, it may be sufficient only to sample mean weights across the path by monitoring mean weights in as few as two separated longitudinally-extending portions of the path, for example, at portions approximately one third and two thirds of the way across the path, or in a central portion and a portion extending along one edge. It is, however, generally advantageous to monitor

( mean weights of food items in four or more longitudinally-extending portions of the path, depending on the number of food items in the stream in a transverse direction, and it is preferable for each of the food items being conveyed at the said given time to be conveyed along one of the said portions so that the weight of all of the food items 5 being conveyed at that time is taken into account in the monitoring operation.

It will be appreciated that the greater the number of longitudinallyextending portions that are weighed separately by the weighing conveyor assembly at the said given time, the more accurate a profile of crosspath mean weight can be obtained.

Assuming that the stream of food items is arranged in rows extending across the path 10 and lanes running transverse to the rows and in the direction of travel (although the rows and lanes may well not be such that the centres of adjacent food items are in exact alignment but may be offset from each other), then the most advantageous arrangement in terms of obtaining an accurate profile of cross-path mean weights is one in which the weighing conveyor assembly is arranged to weigh each lane of the stream separately 15 and the number of longitudinally-extending portions of the path in such an arrangement is then equal to the number of lanes of the stream. Such an arrangement may not be feasible for economic and/or engineering reasons, however, and it has been found that an arrangement in which the path is divided into portions each conveying from 3 to 15 lanes of food items, and the weighing conveyor assembly is arranged to weigh all of the 20 food items conveyed in each of those portions will give sufficient data to give an informative profile across the entire path and to detect any cross-path variation in mean weights. Advantageously, each of the longitudinally-extending portions of the path is arranged to convey from 3 to 15 rows of the food items at a given time, and preferably each of the longitudinally-extending portions of the path is arranged to convey from 9

( s to 100 food items at a given time. The most advantageous arrangement for any particular food item depends on the size of the food item. The ranges of numbers given above are not limited to whole numbers of food items but include fractions of numbers, because, for example, one or more food items being supplied to weighing 5 conveyor assembly may not be resting fully, but only partly, on the weighing conveyor at the said given time.

The arrangement of the invention allows frequent intermittent or substantially continuous monitoring of the weight of food items, and of any cross-path variation in mean weight. A convenient arrangement may be, for example, to monitor the weight 10 of food items every 60 seconds during operation.

Advantageously, the weighing conveyor assembly comprises one or more conveyors for supporting and transporting the stream of food items along the said path and a plurality of weighing devices, for example, load cells, each of which is arranged to weigh the food items conveyed at the said given time in a different one of the said 15 longitudinallyextending portions of the path. Preferably, the conveyor comprises one or more conveyor bands, belts or similar transporting equipment (hereinafter referred to simply as Conveyor bands" or "bands") for transporting food items along each of the longitudinally-extending portions. It is, however, possible to use a single band for transporting the food items of two or more of the said longitudinally-extending 20 portions in conjunction with a plurality of weighing devices provided that the band, as it carries the said food items, is not held under tension, but limply, so that different longitudinally-extending portions of the band can be weighed separately by their associated weighing devices and meaningful results obtained.

The apparatus of the invention advantageously forms part of a food processing

line also comprising one or more processing stations and one or more conveyors arranged to transport the multiplicity of food items to the or each processing station, the processing line being supplied with food items from an initial supply station. When the apparatus of the invention is situated in such a processing line, it is possible to 5 detect variations in mean weights of individual food items across the line and respond thereto. For example, when the processing line is being used for the manufacture of baked food items and the food items are dough pieces supplied from an initial supply station comprising dough sheeting, cutting and/or moulding equipment or wire-cut extrusion equipment, and the dough pieces are transported to an oven, if the data I O processor indicates variation in mean weights across the line, operation of the initial supply station can be adjusted accordingly to minimise or substantially eliminate any such variation.

In order to enable the data processor to calculate the mean weight of the food items conveyed in each of the said longitudinally-extending portions of the path at the 15 said given time, the data processor should generally also be supplied with data concerning the number of food items in each of the said portions at the said given time.

In some circumstances it may be reasonable to assume that the number of food items being conveyed in each of the said portions at any given time is constant even though food items are continuously being supplied to the conveyor assembly and continuously 20 discharged from it. In those circumstances, the number can readily be determined by counting, measuring and/or calculating initially and the data processor supplied with the necessary data.

When the weighing conveyor assembly is situated in a processing line as referred to above, it may well be found that the number of food items on each of the said

longitudinally-extending portions of the path can vary significantly during processing because of variations in the rate at which the initial supply station is operating relative to the speed with which the weighing conveyor assembly is transporting the food items.

Such variations, which effect the separation between the food items in a longitudinal 5 direction, that is to say, in the direction of travel, should be taken into account by the data processor in order to give an accurate output for the mean weights. Preferably, therefore, the data processor is supplied with data concerning the rate of supply of food items to the weighing conveyor assembly (or at least the rate at which the initial supply station is supplying food items to the processing line) , one or more monitors being 10 provided to supply such data. Such data should enable the separation between the centres of adjacent food items in a longitudinal direction on the weighing conveyor assembly at the said given time to be determined assuming that the speed with which the weighing conveyor assembly is transporting the food items is also known, and a further monitor for monitoring that speed is advantageously also provided. Assuming 15 that the lengths of the said longitudinallyextending portions of the path are known (and they are, advantageously, each of the same length as each other and, preferably, each of the same length as the said path), and the number of lanes of food items conveyed along each of the said portions is also known, then the number of food items being conveyed in each of the said portions of the path at the given time can be calculated by the data 20 processor. In operation, it may sometimes be found in practice that the position of the stream of food items being transported along the food processing line moves to a small extent in a transverse direction before reaching the weighing conveyor assembly. Such movement may be due, for example' to localised stretching or distortion of the

conveyor band or bands on which the food items are being conveyed. Such movement of the food items in a transverse direction might sometimes be sufficient to affect the monitoring operation of the invention, especially in portions of the path that extend along the edges of the stream, because the number of food items in those portions might 5 in fact be greater in one of the edge portions and less in the other edge portion than is assumed by the data processor. Such movement can, however, be taken into account in the monitoring operation of the invention in a number of ways. Firstly, the weighing conveyor assembly may be arranged to be movable in a transverse direction and, in operation, may track any transverse movement of the stream of food items by moving I O in that direction to the same extent. Instead, the transverse position of the stream of food items as they reach the weighing conveyor assembly may be tracked and any transverse movement of the stream allowed for by the data processor. In a further option, instead of tracking the position of the stream of food items and moving the weighing conveyor assembly or allowing for it at the data processor, the apparent mean 15 weights of the individual food items of each portion of the path can be obtained and a manual adjustment made to the result to allow for any transverse movement of the stream. Finally, the weighing conveyor assembly may be arranged to weigh any food items of the food stream that reach the weighing conveyor but are outside its normal path on each edge so that that weight can be taken into account in calculating the mean 20 weight of individual food items in the said edge portions.

On a production line incorporating the apparatus of the invention, it may be advantageous to have one or more additional weighing conveyor assemblies installed in series along the line. Each of the weighing conveyor assemblies may be provided with a data processor, or the weighing conveyor assemblies may be connected in a network to

( a central data processor. Advantageously, for the sake of simplification, the weighing conveyor assemblies are each of the same dimensions so that it can be assumed by the or each data processor that they hold the same number of food items as each other at any given time and are preferably arranged to convey the food items at substantially the 5 same speed as each other, in operation. The outputs from the different weighing conveyor assemblies can be compared to give further information on processing. It is then possible to deduce mean weights of the food items before and after a process step to gain information on that process step. For example, when the processing line is being used for the manufacture of baked food items and the food items are dough 10 pieces, a weighing conveyor assembly may be installed to enable the mean weights of the food items to be monitored across the line before they reach an oven in which they are baked and a further weighing conveyor assembly may be installed to enable the means weights of the food items to be monitored after they have lee the oven, so that, allowing for the time taken for the food items to travel from the first weighing conveyor 15 assembly to the second, water loss during baking can be deduced and monitored.

In another application of such an arrangement, a pair of weighing conveyor assemblies may be installed in a processing line with one situated upstream of, and the other situated downstream of, a pick-up, enrobing or coating station in which food items acquire a layer or coating of another substance, for example, chocolate, fondant, 20 jam or caramel. With such an arrangement, information on the mean weight of the layer or coating acquired by the food items across the line can be monitored by comparing data from the upstream and downstream weighing conveyor assemblies taking the time taken for the food items to travel from the downstream to the upstream assemblies into account. Operation of the pick-up, enrobing or coating station, which may involve the

application of relatively expensive ingredients, can then be adjusted to optimise performance. Such arrangements as referred to above make it is possible to exercise closer control over the individual process steps with inherent cost savings.

5 Advantageously, in a processing line comprising a plurality of processing stations, weighing conveyors assemblies are arranged upstream and downstream of each processing station so that information can be gained about each process step and the situation monitored as closely as is desired. When each of those weighing conveyor assemblies has an associated data processor, then, preferably, each data processor, 10 except for the most upstream one in the processing line, is arranged to feed back data to the data processor immediately upstream of it, in operation. When the weighing conveyor assemblies are connected in a network to a central data processor, data from any one of the weighing conveyor assemblies may be combined with data from any of the other weighing conveyor assemblies in any desired manner.

15 Where a processing line incorporates a station at which the configuration of the pattern of the food items on the conveyor bands is adjusted, for example, by equipment known as a Rolodex, from say, offset rows to aligned rows as mentioned above, there may occasionally be short periods during which the separation between the food items in a longitudinal direction is varied. Preferably, operation of any such equipment should 20 also be monitored and any such variation taken into account at the or each data processor operating downstream of the said equipment.

The invention further provides a weighing conveyor assembly arranged to convey a multiplicity of food items at any given time arranged in a stream along a path, food items being continuously supplied to the weighing conveyor assembly, conveyed

( by it in the said stream along the said path and then discharged from it, in operation, the multiplicity of food items of the stream being in a pattern that extends longitudinally in the direction of travel along the path and transversely to the said direction, the weighing conveyor assembly being arranged to weigh the food items being conveyed at a given 5 time in each of a plurality of longitudinally-extending portions of the path, the said portions extending substantially parallel to each other, and the weighing conveyor also being arranged to emit data dependent on the weight of the food items being conveyed at the said given time in each of the said portions.

Food processing apparatus, a food processing line and a food processing 10 method in accordance with the invention will now be described, by way of example, with reference to the accompanying drawings, in which: Fig. I is a schematic diagram of a food processing line including food processing apparatus in accordance with the invention; Fig. 2 is a diagrammatic perspective view of a weighing conveyor assembly of 15 the food processing apparatus of the invention; Fig. 3 is a diagrammatic side view, not to scale, of the weighing conveyor assembly of Fig. 2; Fig. 4 is a diagrammatic plan of a portion of the weighing conveyor assembly of Figs. 2 and 3 with some parts of the apparatus omitted for clarity; and 20 Figs. 5 to 8 are diagrams of parts of the processing line of Fig. I. Referring to the accompanying drawings and initially to Fig. 1, a food processing line for the production of biscuits includes a supply station 1 in the form of a moulder for producing moulded pieces of biscuit dough. The processing line also comprises a processing station in the town of a tunnel oven 2, two further processing

( stations 3 and 4, respectively, and a packaging station, indicated generally by the reference numeral 5.

The moulder 1 comprises a moulder roll la (see Fig. 5) having a multiplicity of biscuit moulds on its curved surface and a co-operating forcing roll (not shown), the 5 rolls being arranged with a nip or narrow gap between them into which dough is fed, in operation. Such a moulder is known in the art.

The tunnel oven 2 comprises a housing, a conveyor arranged to transport the dough pieces through the housing and a multiplicity of heating elements within the housing arranged to heat, and thereby bake, the dough pieces. Such tunnel ovens are 10 known in the art. The processing station 3 is a fondant pick-up station and the processing station 4 is a chocolate pick-up station which are also both known in the art. They each comprises a bath of fondant or chocolate, respectively, through which the baked dough pieces are arranged to travel partly submerged, forcing rollers and licking rollers being provided to apply and remove, respectively, the fondant or 15 chocolate until an even layer of the required thickness is applied to one surface of each dough piece. The packaging station S comprises four packaging machines 5a, Sb, Sc and 5d, respectively, (each of a kind known in the art) arranged to operate in parallel.

A conveyor band 6 is arranged between the moulder 1 and the tunnel oven 2 to transport the moulded dough pieces in a stream from the moulder towards the oven. At 20 downstream end 2a of the oven 2 a series of conveyor bands 7 to 13, respectively, are arranged to provide an extended cooling path for baked dough pieces leaving the tunnel oven 2. It can be seen from Fig. 1 that the conveyor bands 7, 9, 1 1 and 13 carry the dough pieces along straight paths, whereas the conveyor bands 8, 10 and 12 have an arcuate configuration in order to provide the necessary length of path and achieve the

desired cooling of the dough pieces in the available floor space.

At the end of the cooling path (the downstream end of the conveyor band 13) a so-called "rotodex" machine 14 is arranged to adjust the relative positions of the dough pieces in the stream. A further arcuate conveyor band 15 is arranged to transport the 5 dough pieces from the rotodex 13 towards the processing station 3 where the food items acquire a layer of fondant. Further conveyor bands 16 and 17 of a length sufficient to allow at least partial cooling and setting of the fondant layer are arranged to transport the biscuits from the processing station 3 to the processing station 4 where they acquire their final outer layer of chocolate. From the processing station 4, the 10 finished stream of biscuits travel by means of a conveyor band 18 to the packaging station S. where each of the packaging machines Sa to 5d are arranged to accept and package biscuits from one longitudinally-extending portion of the stream.

In accordance with the invention, four weighing stations 19, 20, Bland 22, respectively, are installed in the processing line. The weighing station 19 is positioned I S between the conveyor band 6 and the tunnel oven 2. The weighing station 20 is positioned between the conveyor band I S and the processing station 3. The weighing stations 20 and 21 are positioned upstream and downstream, respectively, of the processing station 4.

Each of the weighing stations 19, 2D, 21 and 22 (see Figs. 5 to 8) comprises a 20 weighing conveyor assembly, indicated generally by the reference numeral WCAI to WCA4, respectively, and a data processor DP1 to DP4, respectively. Each of the weighing conveyor assemblies WCAI to WCA4, respectively, are as shown in Fig. 2, and accordingly only one of them, the weighing conveyor assembly WCAI will be described in detail, it being understood that the weighing conveyor assemblies WCA2 to

WCA4, respectively, are similar.

The weighing conveyor assembly WCAI comprises four weigh decks indicated generally by the reference numerals WDI to WD4, respectively, each of which rests on, a weighing device in the form of a load cell Ll to L4, respectively. Each of the weigh 5 decks WD I to WD4 is as shown in Figs.3 and 4, and accordingly only one of them, the weigh deck WDI will be described in detail, it being understood that the weigh decks WD2 to WD4, respectively, are similar.

The weigh deck WD 1 comprises a drive section, indicated generally by the reference numeral 23, and a conveying section, indicated generally by the reference 10 numeral 24.

The drive section 23 comprises a mounting plate 25, which is arranged to rest on the load cell Ll, the mounting plate having an upwardly-extending flange 25a and a pair of upwardly-extending arms 25b and 25c, respectively. A Panasonic brushless DC motor 26 is mounted on the flange 25a, and a roller 27 is mounted to rotate between 15 the arms 25b and 25c, the roller being driven by the motor 26 by means of a toothed timing belt (not shown) which engages a toothed wheel 26a on the motor 26 and a toothed wheel 27a secured to the roller 27. The mounting plate 25 also provides mountings for a supporting framework 28 of the conveying section 24, which has quick release fastening mechanisms 29a and 29b, respectively, which allow the conveying 20 section 24 to be removed rapidly from the drive section 23 for cleaning and/or maintenance. The conveying section 24 comprises a pair of end rollers 30a and Job, respectively, mounted on the supporting framework 28, an intermediate idler roller 31 and a pair of lower idler rollers 32a and 32b, respectively. The rollers 30 to 32 define a

path for conveyor bands, indicated generally by the reference numeral 33. In this particular example, nine separate bands 33a to 33i, respectively, (parts of which are shown in broken lines in Fig.4) are provided, the outermost pair of which at each side edge ofthe weigh deck WDI, that is to say, the bands 33a, 33b and 33h, 33i run around 5 only the end rollers 30a and 30b, while the inner bands 33c to 33g, respectively, run around the end rollers 30a and 30b and also the intermediate roller 31 and the lower rollers 32a, 32b. When the conveying section 24 is mounted on the drive section 23 as shown in Fig. 3, the inner bands 33c to 33g, respectively, where they pass between the lower rollers 32a and 32b are caused to pass round and engage the driven roller 27 of 10 the drive section 23. On rotation ofthe driven roller 27, the inner bands 33c to 33g are caused to move in the sense indicated by the arrow A shown in Fig. 3. That movement of the inner bands 33c to 33g causes the end rollers 30a and 30b to rotate, and they in turn cause the bands 33a, 33b,33h and 33i to move in the same sense as, and at the same speed, as the bands 33c to 33g. Belt tensioning mechanisms 34 are provided to 15 allow adjustment of the tension in upper runs of the bands 33a to 33i between the rollers 30a and 30b.

Each of the weighing decks WD1 to WD4 of the weighing conveyor assembly WCA1 together with their associated load cells L1 to L4, respectively, arealigned adjacent to each other in a row as shown in Fig. 2 so that the upper runs of all of the 20 conveyor bands 33 of all four of the weigh decks together provide a path for the stream of food items being conveyed along the processing line. The conveyor bands 33 of each weigh deck WD1 to WD4, respectively, provide a longitudinally-extending portion of that path. The load cells Ll to L4 are each arranged to transmit signals dependent on the weight of all of the dough pieces being carried by the conveyor bands 33 of their

( respective weighing decks WD1 to WD4 to their associated data processor DPI as shown in Fig. 5.

As referred to above, each of the weighing conveyor assemblies WCA2 to WCA4, respectively, of the weighing stations 20 to 22, respectively, is similar to the 5 weighing conveyor assembly WCA1, the assemblies WCA: to WCA4 being as shown in Figs. 6 to 8, respectively. An encoder El to E4, respectively, for each of the weighing stations 19 to 22 is arranged to monitor the speed of travel of the conveyor bands 33 of each of the weighing conveyor assemblies WCA1 to WCA4 and transmit signals dependent on those speeds to its respective data processor DP 1 to DP4.

10 A further encoder EM is arranged to transmit to the data processors DP I to DP4 data concerning the speed of rotation of the moulder roller 1 a of the moulding station 1.

In addition, the weighing stations 2O, 21 and 22 include another encoder ER arranged to monitor the operation of the rotodex machine 14 and transmit data to the data processors DP2, DP3 and DP4, respectively. The data processor DP2 is arranged to 15 feed back data to the data processor DP I, the data processor DP3 is arranged to feed back data to the data processor DP2 and the data processor DP4 is arranged to feed back data to the data processor DP3.

In operation, dough is fed into the gap between the moulder roll 1 a and the forcing roll of the moulding station I. The moulder roll 1 a and the forcing roll rotate in 20 opposite senses so that dough is forced into the biscuit moulds on the moulder roll. At a predetermined position in its path of rotation, the moulder roll 1 a deposits moulded dough pieces onto the conveyor band 6 in rows in a transverse direction of, for example, 16 dough pieces forming 16 lanes extending in a longitudinal direction, that is to says in the direction of travel. The dough pieces of each row have their centres in approximate

alignment, but adjacent rows are offset from each other so that the centres of adjacent dough pieces in each lane are also offset from each other. The rate at which the moulder station 1 supplies dough pieces to the conveyor 6 depends on the separation between the centres of the biscuit moulds on the moulder roll 1 a, which is constant with 5 any particular moulder roll and can be measured and fed into the data processors DP I to DP4, and the speed of rotation of the moulder roll, which is monitored by the encoder EM. The conveyor band 6 transports the dough pieces to the first weighing station 19 as shown in Fig. I where the dough pieces are deposited on end 35 (see Fig. 2) ofthe 10 upper run of the conveyor bands 33 of each of the four weigh decks WD1 to WD4, respectively, so that, in this particular example, 4 lanes of dough pieces are transported by each ofthe weigh decks. All the conveyor bands 33 of all four weigh decks WD1 to WD4 are travelling at the same speed and convey the dough pieces, which are being continuously supplied onto the conveyor bands, towards the oven 2, depositing them 15 continuously at end 36 of the upper run onto the conveyor of the oven. The load cells L1 to L4 associated with each of the weigh decks WD 1 to WD4, respectively, periodically, at intervals of, for example, 60 sees each send a signal to the data processor DP 1 dependent on the total weight of the dough pieces being conveyed at that time by their associated weigh decks. The speed of travel of conveyor bands 33 of each of the 20 weigh decks WDI to WD4 is monitored by the encoder El, which also sends a signal periodically and at the same time as the load cells L I to L4 to the data processor DP 1.

The data processor DP 1 also receives a signal from the moulder encoder EM dependent on the rate of rotation of the moulder roller 1 a. The data processor DP I has already been supplied with the relevant data concerning the initial separation between the

( centres of the biscuit moulds on the moulder roll 1 a. Assuming that the number of dough pieces in each row is constant and known, which will generally be the case but see the discussion below, the data processor DPI is able to calculate the number of dough pieces (which need not be a whole number) on each of the weigh decks WD I to 5 WD4, respectively, at the time of the signals, and hence the mean weights of the dough pieces on each of the weigh decks WD1 to WD4 at that time. With that information, any variation in the mean weights of the dough pieces from one weigh deck to another across the processing line (that is to say, in a direction transverse to the direction of travel of the dough pieces) can be detected. Monitoring can be continued at intervals 10 throughout operation of the processing line so that any cross-line variation that develops during operation can also be detected.

After leaving the weighing station 19, the dough pieces travel through the tunnel oven 2 while being baked to form biscuits. On leaving the oven 2 the hot baked dough pieces, or biscuits, are carried on the extended cooling path by the conveyors 7 to 13, in 15 turn. During travel around the cooling path, the biscuits cool and lose moisture. They may also become misaligned out of the offset rows in which they were initially placed by the moulder 1, and the rotodex machine 14, located downstream ofthe cooling path, adjusts the position of the biscuits to a desired configuration, which may be, for example, aligned rows of 16 biscuits forming 16 aligned lanes of biscuits in the direction 20 of travel.

ARer travelling on the arcuate conveyor band 15, the biscuits reach the second weighing station 20 as shown in Fig. 3 where the same operation as described above with reference to the weighing station 19 is carried out. The weighing station 20 operates in the same manner as the weighing station 19 except that, in addition, the data

processor DP2 receives data from the encoder ER on the rate of operation of the rotodex machine 14 and that data processor also feeds back data to the data processor DP I of the first weighing station so that the data processor DP I can, by comparing data on the mean weights of the dough pieces before entering the oven 2 and after travelling 5 around the cooling path, given information concerning moisture loss caused by baking.

Immediately after being discharged from the weighing station 20, the biscuits travel through the fondant pick-up station 3 where the biscuits pass, partly submerged through the bath of fondant in order to pick up a layer on their lowermost surfaces. The forcing and licking rollers ensure that one surface of each of the biscuits acquires a layer 10 of the desired thickness of fondant.

After the fondant pick-up station 3, the conveyor bands 16 and 17 transport the biscuits to the third weighing station 21 shown in Fig. 4 located immediately upstream of the chocolate enrober station 4. The weighing station 21 operates in the same manner as the weighing station 20, with the data processor DP3 feeding back data 1 S concerning the mean weights of biscuits across the processing line to the data processor 2 of the weighing station 20 so that the mean weights of the fondant layer on the biscuits can be established.

After leaving the weighing station 21, the biscuits pass through the chocolate enrober station 4 and acquire a coating of chocolate over the fondant layer. They then 20 pass to the final weighing station 22, as shown in Fig. 5, which operates in the same manner as the weighing stations 20 and 21. Data from the data processor DP4 is fed back to the data processor DP3 of the weighing station 21 in order to obtain information on the mean weights of the chocolate layer on the biscuits.

From the weighing station 22, the finished stream of biscuits travels to the

( packaging station 5 where each of the packaging apparatuses 5a to Sd, respectively, packages biscuits from a different longitudinally-extending portion of the stream.

The information gained from the data processors DP I to DP4 allow adjustment of the moulder 1 and/or the other processing stations 2, 3 and 4 to reduce or 5 substantially eliminate cross-line variations in weights of the biscuits arriving at the packaging station 5.

Instead of each of the weighing stations 19, 20, 21 and 22 having its own data processor DP I to DP4, respectively, a central data control unit may be provided to which each set of the weighing conveyor assemblies WCAI to WCA4 is linked in a 10 network and transmits its information. With that arrangement, data from any of the weighing conveyor assemblies WCA1 to WCA4 can be combined with data from any of the other weighing conveyor assemblies in any desired manner.

It may be found, in operation, that the position of the stream of food items being transported along the food processing line moves to a small extent in a transverse 15 direction before reaching one or more of the weighing conveyor assemblies WCAI to WCA4. Such movement may be due, for example, to localised stretching or distortion ofthe conveyor band or bands on which the food items are being conveyed prior to reaching the weighing conveyor assemblies WCA1 to WCA4.. Such movement of the food items in a transverse direction might sometimes be sufficient to affect the 20 monitoring operation, especially in portions of the path that extend along the edges of the stream, because the number of food items in those portions might in fact be greater in one of the edge portions and less in the other edge portion than is assumed by the data processor associated with the weighing conveyor assembly in question. Such movement can, however, be taken into account in the monitoring operation of the

invention in a number of ways. Firstly, the or each weighing conveyor assembly may be arranged to be movable in a transverse direction and, in operation, may track any transverse movement of the stream of food items by moving in that direction to the same extent. Instead, the transverse position of the stream of food items as they reach 5 the or each weighing conveyor assembly may be tracked and any transverse movement of the stream allowed for by the associated data processor. In a further option, instead of tracking the position of the stream of food items and moving the or each weighing conveyor assembly or allowing for it at the associated data processor, the apparent mean weights of the individual food items of each portion of the path can be obtained and a 10 manual adjustment made to the result to allow for any transverse movement of the stream. Finally, the or each weighing conveyor assembly may be arranged to weigh any food items of the food stream that reach the weighing conveyor but are outside its normal path on each edge so that that weight can be taken into account in calculating the mean weight of individual food items in the said edge portions. That can be 15 achieved by providing each weighing conveyor assembly with two further weighing decks, which may be similar to the weighing decks WD I to WD4, with one of the additional weighing decks positioned alongside the weighing decks WD 1 and the other positioned alongside the weighing deck WD4.

Claims

Claims

1. Food processing apparatus which comprises a weighing conveyor assembly and a data processor, the weighing conveyor assembly being arranged to convey a multiplicity of food items at any given time arranged in a stream along a paths food items 5 being continuously supplied to the weighing conveyor assembly, conveyed by it in the said stream along the said path and then discharged from it, in operation, the multiplicity of food items of the stream being in a pattern that extends longitudinally in the direction of travel along the path and transversely to the said direction, the weighing conveyor assembly being arranged to weigh the food items being conveyed at a given time in each 10 of a plurality of longitudinally-extending portions of the path, the said portions extending substantially parallel to each other, and the weighing conveyor also being arranged to send data dependent on the weight of the food items being conveyed at the said given time in each of the said portions to the data processor, the data processor being arranged to give an output that represents a mean weight of individual food items 15 conveyed at the said given time in each of the said portions of the path.

2. Food processing apparatus as claimed in claim 1, wherein the said longitudinally-extending portions of the path comprise a portion extending along, or adjacent to, an edge of the path, or portions extending along, or adjacent to, each edge of the path, and/or one or more other portions.

20 3. Food processing apparatus as claimed in claim I or claim 2, wherein there are four or more of the said longitudinally-extending portions of the path.

4. Food processing apparatus as claimed in any one of claims I to 3, wherein the said longitudinally-extending portions of the path are each arranged to convey from 3 to 15 lanes of food items and the weighing conveyor assembly is arranged to weigh all of

( the food items conveyed in each of those portions at the said given time.

5. Food processing apparatus as claimed in any one of claims 1 to 4, wherein the apparatus is arranged to monitor the weight of food items intermittently or substantially continuously. 5 6. Food processing apparatus as claimed in any one of claims 1 to 5, wherein the weighing conveyor assembly comprises a conveyor for supporting and transporting the stream of food items along the said path and a plurality of weighing devices, each of which is arranged to weigh the food items conveyed at the said given time in a different one of the said longitudinally- extending portions of the path.

10 7. Food processing apparatus as claimed in any one of claim 6, wherein the conveyor comprises one or more conveyor bands, belts or similar transporting equipment for transporting food items along each of the longitudinally-extending portions. 8. Food processing apparatus as claimed in any one of claims I to 7, which comprises 15 a monitor for monitoring the rate of supply of food items to the weighing conveyor assembly and sending data concerning the said rate to the data processor.

9. Food processing apparatus as claimed in any one of claims I to 8, which comprises a monitor for monitoring the speed with which the weighing conveyor assembly is arranged to transport the food items, in operation 20 10. A food processing line comprising a supply station, one or more processing stations and one or more conveyors arranged to transport a multiplicity of food items from the supply station to the or each processing station, the line also comprising food processing apparatus as claimed in any one of claims 1 to 9.

11. A food processing line as claimed in claim 10, which includes a monitor for

monitoring the rate at which the supply station is supplying food items.

12. A food processing line as claimed in claim 10 or claim 11' wherein one or more additional weighing conveyor assemblies are installed in series along the line.

13. A food processing line as claimed in claim 12, wherein each of the weighing 5 conveyor assemblies is provided with a data processor 14. A food processing line as claimed in claim 12, wherein each of the weighing conveyor assemblies are connected in a network to a central data processor.

1 S. A food processing line as claimed in any one of claims 12 to 14, wherein weighing conveyor assemblies are arranged upstream and downstream of the or each 10 processing station.

16. A food processing line as claimed in any one of claims 10 to 15, wherein the supply station is dough sheeting, cutting and/or moulding equipment, or wire-cut extrusion equipment and the or one of the processing stations is an oven.

17. A food processing line as claimed in claim 16, wherein the line includes at least 15 one further processing station being a pick-up, enrobing or coating station for the food items. 18. Food processing apparatus substantially as hereinbefore described with reference to, and as shown in, the accompanying drawings.

19. A food processing line substantially as hereinbefore described with reference 20 to, and as shown in, the accompanying drawings.

20. A food processing method in which a weighing conveyor assembly conveys a multiplicity of food items arranged in a stream along a path, the food items being continuously supplied to the weighing conveyor assembly, conveyed by it in the said stream along the said path and then discharged from it, the multiplicity of food items of

the stream being in pattern that extends longitudinally in the direction of travel along the path and transversely to the said direction, the weighing conveyor assembly weighing the food items being conveyed at a given time in each of a plurality of longitudinally extending portions of the path, the said portions extending substantially parallel to each 5 other, and the weighing conveyor sending data dependent on the weight of the food items being conveyed at the said given time in each of the said portions to a data processor, the data processor giving an output that represents a mean weight of individual food items conveyed at the said given time in each of the said portions of the path. 10 21. A food processing method as claimed in claim 20, wherein the said longitudinallyextending portions of the path comprise a portion extending along, or adjacent to, an edge of the path, or portions extending along, or adjacent to, each edge of the path, and/or one or more other portions.

22. A food processing method as claimed in claim 20 or claim 21, wherein there 1 S are four or more of the said longitudinally-extending portions of the path.

23. A food processing method as claimed in any one of claims 20 to 22, wherein the said longitudinally-extending portions of the path each convey from 3 to 5 lanes of food items and the weighing conveyor assembly weighs all of the food items conveyed in each of those portions at the said given time.

20 24 A food processing method as claimed in any one of claims 20 to 23, wherein the weight of food items is monitored intermittently or substantially continuously.

25. A food processing method as claimed in any one of claims 20 to 24, wherein the rate of supply of food items to the weighing conveyor assembly is monitored and data concerning the said rate is sent to the data processor.

( 26. A food processing method as claimed in any one of claims 20 to 25, wherein the speed with which the weighing conveyor assembly transports the food items is monitored. 27. A food processing method as claimed in any one of claims 20 to 26, wherein 5 the weighing conveyor assembly is operating in a food processing line comprising a supply station, one or more processing stations and one or more conveyors transporting a multiplicity of food items from the supply station to the or each processing station.

28. A food processing method as claimed in claim 27, wherein the rate at which the supply station is supplying food items is monitored.

10 29. A food processing method as claimed in claim 27 or claim 28, wherein one or more additional weighing conveyor assemblies are installed in series along the line, and each assembly sends outputs to one or more data processors.

30. A food processing method as claimed in claim 29, wherein weighing conveyor assemblies are arranged upstream and downstream of the or each processing station.

15 31. A food processing method as claimed in claim 30, wherein each of the weighing conveyor assemblies has an associated data processor, and each data processor, except for the most upstream one in the processing line, feeds back data to the data processor immediately upstream of it.

32. A food processing method as claimed in any one of claims 27 to 31, wherein 20 the food items are pieces of dough.

33. A food processing method as claimed in claim 32, wherein the supply station is dough sheeting, cutting and/or moulding equipment or wire-cut extrusion equipment and the or one of the processing stations is an oven.

34. A food processing method as claimed in claim 33, wherein the line includes at

least one further processing station being a pick-up, enrobing or coating station for the food items.

35. A food processing method substantially as hereinbefore described with reference to the accompanying drawings.

S 36. A weighing conveyor assembly arranged to convey a multiplicity of food items at any given time arranged in a stream along a path, food items being continuously supplied to the weighing conveyor assembly, conveyed by it in the said stream along the said path and then discharged from it, in operation, the multiplicity of food items of the stream being in a pattern that extends longitudinally in the direction of travel along the 10 path and transversely to the said direction, the weighing conveyor assembly being arranged to weigh the food items being conveyed at a given time in each of a plurality of longitudinally-extending portions of the path, the said portions extending substantially parallel to each other, and the weighing conveyor also being arranged to emit data dependent on the weight of the food items being conveyed at the said given time in each 15 of the said portions.

37. A weighing conveyor assembly as claimed in claim 36 and adapted for use in the food processing apparatus as claimed in any one of claims I to 19 or in the food processing method as claimed in any one of claims 20 to 35.