Classifying – separating – and assorting solids – Sorting special items – and certain methods and apparatus for... – Separating means
Reexamination Certificate
1999-08-23
2004-03-30
Walsh, Donald P. (Department: 3653)
Classifying, separating, and assorting solids
Sorting special items, and certain methods and apparatus for...
Separating means
C209S592000, C209S650000, C209S657000, C177S025110
Reexamination Certificate
active
06712221
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
In the food processing industry it is a well known problem that it is difficult to obtain portions consisting of a number of parts (such as pieces of fresh or frozen fish, meat or poultry) when it is additionally required that a predetermined precise portion weight (possibly with tight tolerances) be combined with a pre-determined number of pieces, in particular in those cases where the weight of the individual pieces deviates in such a manner that the weight distribution of the pieces is non-normal or changing. Portions having a fixed number of pieces or a number in a chosen interval may be aimed at.
A weight distribution may be normal, whereby the usual concepts ‘average and spread’ may be used as well as well tested statistical calculation procedures. The weight distribution may also be non-normal, because of the fact that the charge or flow of material being weighed may, at an earlier stage, already have been subjected to sorting and possible removal of all items within certain weight intervals, and this will have removed the possibility for traditional statistical calculations.
2. Description of Related Art
Known methods to obtain portions of the kind discussed comprise manual weighing which is a very stressful activity and in most cases the built-in security for the customer in the form of over-weight means a considerable loss for the manufacturer.
Two principally different automatic methods are known: The combination weighing principle and the accumulation weighing principle. In the first, a number of weighed parts or part portions are disposed in a number of weighing bins or in the combination bins of such weighing bins, whereupon, based on the part weights measured, a computer calculates which bin sub portions in combination will constitute the portion which is closest in weight to the predetermined target weight. The limitation of this method is in particular that the number of parts which is available for the combination is limited. In particular when the individual weights of the parts deviate, possibly considerably from each other (as in the case of fish, poultry, or meat) the combinations will often deviate more than is desirable from the target weight, and this will, as in the manual case, mean a loss for the manufacturer.
In the accumulation weighing principle several full portions are currently and even concurrently built up. The individual parts are conveyed forward in a line and are weighed on a dynamic weigher, and the weights are registered successively by a computer which hence keeps track of the relative position in the line and the respective weights. A distribution unit places the parts selectively in collecting bins, whereby the portions are built up, while the accumulated weights of parts in the individual bins are registered in the computer. The allocation of the individual parts to the various bins continues as long as the accumulated weight in the bin is still below the target weight, until, finally, the bin waits for a part which in the particular portion would just bring the portion weight to the desired value. In order to achieve a reasonable capacity one will have to accept that it may become necessary—and even standard practice—to perform the last discharge with a part which will give an overweight to the portion because it will be an almost lucky coincidence if among the arriving and already weighed parts there will be one which will provide the precise desired total weight.
In the last mentioned method a noticeable improvement has been achieved, cf. GB-C-2,116,732, in that based on a qualified estimate of the freight distribution in the mass of parts one causes a selective sorting out in such a manner that parts with a weight above and below the average, respectively, are brought together to make part portions which in order to fill to the desired weight need only one or a few parts which have the average weight. The method hence is based on the probability consideration that, of the normal distribution, there will be the largest number of those parts which have the respective average weight, whereby the final filling of the portions may occur the fastest when the waiting is for parts of in particular this group.
This method is quite advantageous, once it has been ascertained beforehand, by sampling, what the average weight of the parts is, and in which weight range the parts occur, i.e. what the so-called spread is. The current calculations, based on a preprogrammed normal distribution curve, may be performed with limited data (equipment, a.o. because according to normal practice one may allow that a new part may simply be fed to the first of such part portions which waits for a part in the weight class represented by that part, even though, as will be discussed below, the part might have been placed more appropriately in another of these part portions.
However, it has been realized in practice that certainly within the area of the food industry dealt with here it is difficult to retain the knowledge about the weight distribution in the mass of parts as both the average weight and the spread may fluctuate between e.g. different loads of raw material. Furthermore it is in connection with the present invention considered that it may be desirable to create particular assortments from a given mass of parts which would completely change the image of the distribution of the mass which is available for the creation of the portions discussed. As an example, the removal of in particular those parts which have the average weight may entail that there will be no parts available for the conclusion of the portions according to the method described above.
It is a well known practice that a charge is sorted beforehand, e.g. by taking out particular qualities. The portioning equipment could be better utilized if this sorting occurred in conjunction with the portioning, but with the associated deliberate change in the part weight distribution the remaining parts usable for the portioning will no longer ex-hibit the normal distribution. In this way a sorter or batcher of the said known type is given a task which it is not suited to solve. If it is desired in the industry to work with parts which are reliably present in a normal distribution the raw materials are more expensive which again gives a more expensive finished product.
SUMMARY OF THE INVENTION
The present invention relates to a method for portioning which uses certain aspects of the accumulation weighing principle but which makes it possible to distribute the individual parts to the various collection bins for the building of portions essentially independently of the weight distribution of the product parts.
It is a modern trend in the food industry that raw materials are processed one way or the other to a still increasing extent. The raw materials as delivered to the processing industries could well exhibit a normal distribution, but over time it has been a steadily increasing problem that the processed materials, which are to be packed or batched, are no longer normally distributed. Thus, it has been practically impossible or rather expensive to effect batching to a specific target weight and therewith to a fixed price of the packings. Instead, it has become a common practice to batch desired numbers of articles, e.g. four cutlets, and to weigh the individual packings as a basis for an automatic printing of weight and price or associated labels. This technique is fairly simple, but for different reasons all the links in the chain from the processing factory over wholesalers and retailers to customers would in fact prefer packings of fixed weights and prices.
Also, there are special types of packings, which could be good candidates for a “batching to predetermined weight”, even without this having crossed the minds of the relevant experts because an automatic batching would seem completely impossible. As an example, it is a well known practice that cheese manufacturers may produce not only whole cheeses, but also larger and smaller pieces of
Bomholt John
Kvisgaard Thorkild
Miller Jonathan R
Nixon & Peabody LLP
Safran David S.
Scanvaegt A/S
Walsh Donald P.
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