Patent Application
20070193787
The present invention relates to a technique for weighing and collecting batches of articles, each batch having a total weight within a given target weight interval.
Within industries such as foodstuff industry, combined weighing and batching machines have been described in publications such as DE 3 540 165, EP 0 097 532, EP 0 736 754, GB 2 147 111, U.S. Pat. No. 4,382,527, U.S. Pat. No. 4,811,256, U.S. Pat. No. 4,901,807, U.S. Pat. No. 5,753,866, U.S. Pat. No. 5,813,195, U.S. Pat. No. 6,262,377, U.S. Pat. No. 6,360,870, U.S. Pat. No. 6,441,322, EP 0 592 349 and EP 0 746 113, all of which are hereby included in the present specification by reference.
The publication U.S. Pat. No. 4,901,807 describes a combination weigher comprising a number of receptacles for accumulating a batch of products, each receptacle emptying the product into a multiple compartment weighing device wherein the volume of the weighing compartments are substantially equal.
A combination of a weighing and batching machine such as described in U.S. Pat. No. 4,901,807 suffers, however, from certain limitations due to the size of the receptacles and weighing compartments. Collecting one batch with a high total weight requires combination of a high number of weighing compartments to be emptied at one time. This operation is contemplated to be limiting to the throughput of the machine. The present invention seeks to provide an improved combination weighing machine having a high throughput.
From GB 2 147 111 a weighing and batching machine is known including a number of weighing units arranges circularly on a frame. Two of the weighing units have weighing hoppers which are substantially greater in volume than those of the other units. The weight of the articles received in the two greater volume weighing units are combined with the weight of the articles received in the smaller volume weighing units and when a combination is obtained having a weight greater than the reference weight, the two weighing units including a greater volume weighing unit and a smaller volume weighing unit are emptied. No specific definition of difference between the weighing volumes of the smaller and the greater volume weighing units is described and no alternative combination criteria than the combination exceeding a specific reference weight is described.
In EP 0 736 754, a weighing and batching machine is known, including a single major volume weighing unit and a number of differently sized smaller volume weighing units. The combination of the larger volume batch and one of the smaller volume batches is established for obtaining a match with a reference value.
Due to the recognition of certain drawbacks in the technique used in conventional weighing and batching machines, it has been realised that there is a need for an improved high throughput weighing and batching machine in which the weighing and batching may be performed by employing multiple receptacles or weighing pans having different volumes and thereby possibly accumulating in one or more of the receptacles a large portion having a weight close to the desired target weight and thereby reducing the number of specific quantities to be combined into the target batch, and at the same time improving the accuracy of the weighing and batching operation as compared to the prior art weighing and batching machines in which in certain instances the articles or batches present in the weighing units are not combinable into a combined weight corresponding to the reference or target weight which is to be obtained.
A particular feature of the present invention relates to the fact that the weighing and batching system according to the present invention further allows the addition of containment receptacles for containing the portion collected in the small weighing pans thereby adding a pipeline-like or queue function to the weighing and batching machine.
The above need, the above object, the above feature and the above advantage together with numerous other objects, advantages and features which will be evident from the below detailed description of the first and presently preferred embodiment of the weighing and classifying system according to the present invention are obtained according a first aspect of the present invention by a weighing and batching system for weighing and collecting a batch of articles within a target weight interval, the system comprising:
The weighing and batching system according to the present invention may further be fitted with a microprocessor based calculation unit connected to a data collecting unit. The data collecting unit collecting information regarding the weight of the batches in each of the weighing pans or receptacles and storing this information for the calculation unit to access this information in order to calculate a combination of weighing pans and/or receptacles to be collected into the target batch.
The calculation unit and the data collecting unit may be constituted by at least one microprocessor unit with a built-in data collection unit, such as an A/D converter, alternatively the electrical signal from the weighing units may be digital, such as from a digital weighing transducer, the microprocessor may then receive the signal directly alternatively via a multiplex device for receiving signals from a larger number of weighing units and/or weighing transducers.
The weighing and batching system according to the present invention includes the reject device mounted below the timing hopper, solving the problem inherent in existing weighing or batching machines or systems, namely the problem of how to handle a situation in which any combination of weighing pans and/or receptacles does not result in a target weight within the specified target weight interval. The number of weighing pans and/or receptacles to be emptied are at least one, and may be as high as the total number of weighing pans and/or receptacles. The reject device may be constituted by the timing hopper. Furthermore, in the reject state, the articles may be rejected for destruction or alternatively be recycled.
The target batch weight and the tolerances, or the weight interval wherein the target batch weight must lie, may be provided to the system by an input device such as a touch screen device or a keyboard device mounted on the frame or connected to the calculation unit by wiring or wireless connections or any other input means, such as pointing devices or voice command recognition.
Alternatively, the calculation unit and/or the data collecting unit may be connected to a communication device such as a NIC card, preferably Ethernet-based or a WLAN device, a WPAN device (IEEE 802.11.F/IEEE 802.15.2), a device for establishing a data connection using a wireless protocol such as GSM data, GPRS, EDGE, IrDA, Blue Tooth or any other communication method or protocol, a modem connected to a phone line, either analogue or digital, or any other communication device for establishing a path of communication over a local network, a wide area network, a global area network, the Internet or any other communication network. The communication path is established to an external, remotely placed computer or server, e.g. a computer or server placed in a control room, the computer or server including a program for monitoring the operation of one or more weighing and batching systems in a production hall.
The weighing and batching system according to the present invention may further include a surveillance system such as one or more cameras for remotely monitoring the operation of the weighing and batching machine.
In an alternative embodiment of the present invention, a vision system comprising one or more cameras and image-analysis software may constitute the weighing transducer, e.g. by detecting the amount of articles by analysing an image of the top of each of the weighing receptacles, and from knowledge of the density of the articles thereby determine the weight of the portion. The camera or cameras may also be used to count the number of articles.
According to a first advantage of the embodiment of the system according to the present invention is that in the weighing and batching machine the feeder system may be constituted by at least one vibrating and reciprocating device, alternatively a conveyor belt system, feed screw or any other conveying device or any combination thereof. The feeder system, and all other components of the system, may be selected to accommodate special requirements regarding the properties of the products or articles to be weighed and batched, such as fragility or stickiness of the products.
According to a first feature of the embodiment of the system according to the present invention the feeder system further comprising a plurality of vibrating feeders mounted in the frame below the vibrating and reciprocating device and above the first and the second plurality of weighing pans, each of the vibrating feeders receiving the articles, the vibrating feeders releasing the articles into the first and the second plurality of weighing pans in a substantially even distribution, alternatively the distribution is substantially Gaussian.
According to a second advantage of the embodiment of the system according to the present invention the system may further comprise a conveyor system mounted below the timing hopper, the conveyor system conveying receptacles for receiving a batch of articles having a specific total weight or a total weight within a given weight interval.
According the to teachings of the present invention the system may further comprise a microprocessor monitoring and calculation device for monitoring the weight of each of the portions in each of the weighing pans of the first and the second plurality, the calculation unit calculating a combination of the batches resulting in a total batch weight within the target weight interval. The combination is preferably based on selecting at least one of the weighing pans of the second plurality and at least one of the weighing pans of the first plurality.
According to a second feature of the embodiment of the system according to the present invention the system may further comprise a plurality of receptacles mounted in the frame, each of the receptacles mounted below the outlet, each of the receptacles defining a fifth open end oriented upwardly and being positioned below the outlets of the feeder system for receiving in each of the receptacles a portion of the articles discharged from a respective outlet, each of the receptacles positioned above a specific weighing pan of the first plurality, the plurality of receptacles corresponding to the first plurality of weighing pans.
According to a third feature of the embodiment of the system according to the present invention is that the system may further comprise a plurality of receptacles mounted in the frame, each of the receptacles defining a sixth open end oriented upwardly and being positioned below a specific weighing pan of the first plurality for receiving in each of the receptacles a portion of the articles, the plurality of receptacles corresponding to the first plurality of weighing pans.
Preferably the weighing and batching system according to the present invention may have the feeder system, the first and said second plurality of weighing pans and/or the timing hopper and/or the assembling pans being crafted in stainless steel, such as AISI 304 or AISI 316 or any combination thereof. The first and/or the second plurality of weighing pans and/or the timing hopper and/or the assembling pans may be profiled stainless steel.
According to the present invention the first plurality is at least two, preferably twelve and the second plurality is at least two, preferably six.
According to a fourth feature of the embodiment of the system according to the present invention the first plurality of weighing pans is 1 to 10 times said second plurality, such as 1 to 7 times, such as 1.5 to 5 times, such as 1.5 to 3.5 times, such as equal to said second plurality, such as 1 to 2 times, such as 2 to 3 times, such as 3 to 4 times, such as 4 to 5 times, such as 5 to 6 times, such as 6 to 7 times, such as 7 to 8 times, such as 8 to 9 times, such as 9 to 10 times.
According to a third advantage of the embodiment of the system according to the present invention the first circumference is substantially circular, elliptical, rectangular, square or any combination thereof.
According to a fifth feature of the embodiment of the system according to the present invention the feeder system, the first and the second plurality of weighing pans and/or the timing hopper may be coated with ceramics, polytetrafluoroethene, a nylon mat, a rubber mat or any combination thereof.
According to a second aspect of the present invention a method for weighing and collecting a batch of articles within a target weight interval, the method comprising:
According to the teachings of the present invention the method according to the second aspect of the present invention described above may further include any of the features of the weighing and batching machine previously described.
The present invention is now to be further described with reference to the drawings in which
The vibrating feeder 18 receives the product or article from the top cone 16 and the product is then delivered into a first number of assembling pans 20 and into a second number of larger weighing pans 30. Below each of the assembling pans 20, a respective weighing pan 22 is positioned.
The large weighing pans assembles a larger portion of products or articles close to the predetermined target weight, such as 75 to 80 percent preferably 90 percent of the target weight. In order to obtain a high throughput of products into the large weighing pan, products are fed from the top cone 16 into the large weighing pan 30 by a conveyor belt feeder 26 with a shutter device 28. The vibrating feeder 18 is controlled by a central computer or processing unit (not illustrated) that receives an electrical signal from each of the individual weighing pans 30 and 22, representing the weight of the content of the individual weighing pans 30 and 22 and generated by a weighing device included in the weighing pan. The computer controls the vibrating feeder 18 and may stop the vibrating feeder 18 when the content of the weighing pan 22 is nearing a predetermined weight.
The assembling pans 20 may be omitted, however, the assembling pans 20 are preferably provided and positioned above the weighing pans 22, either in registration with the weighing pans 22, alternatively displaced or offset with respect to the weighing pans 22. Alternatively, the hybrid weigher may be provided having additional assembling pans positioned above the weighing pans 30. Further alternatively, the assembling pans may be shifted from their preferred positions above the weighing pans to positions below the weighing pans.
The computer includes information regarding the weight of the content of each weighing pan 22 in the hybrid weigher 10 at any time as the computer has received signals as discussed above from the individual weighing pan 22 and will perform calculations when combining the weights of the products in the weighing pans 30 and the weighing pans 22 in order to obtain a predetermined batch weight.
The number of assembling pans 20 and weighing pans 22 and 30 is limited only by the geometrical configuration of the individual assembling pans 20 and weighing pans 22 and 30 and the overall geometry of the hybrid weigher 10; also the geometry of the individual assembling pans may differ.
The basic functionality of the hybrid weigher is the combination of small and large weighing pans, in the most basic form a hybrid weigher comprising only weighing pans may be envisioned. The feeder or feeders may then distribute the product or products into these weighing pans and the computer may at any time calculate a combination of these weighing pans that obtains a total batch weight within the target weight interval.
The predetermined batch weight is supplied to the computer by an operator using an input device on the hybrid weigher 10 or from an external computer connected to the computer in the hybrid weigher 10 by a communication line such as the internet or via an intranet constituted by wireless connections or connections by cable.
In the presently preferred embodiment of the present invention the computer calculates a combination of a weighing pan 30 and one or more weighing pans 22 corresponding to a total batch weight within the predetermined target weight interval.
The establishment of the target weight interval may be subject to a number of considerations. The target weight interval may be fixed by setting a maximum weight that the target weight under no circumstances may exceed combined with a lower tolerance level. An alternative to this may be to establish a lower and a higher limit around a given specific weight. A second alternative is to specify a minimum weight that the target weight may under no circumstances be below.
The computer signals the weighing pans 22 and 30 to empty their contents into an assembling hopper 24 mounted below the weighing pans 22 and 30. The assembling hopper 24 may be integrated with the timing hopper 32. The top circumference of the assembling hopper 24 may have an overall geometrical configuration corresponding to the placement of the weighing pans and assembling pans 20, so that the emptying of the weighing pans 22 and 30 does not result in any spilling of products.
Below the assembling hopper 24 a timing hopper 32 is mounted in register therewith for discharging the products into a packaging machine, packaging the products into any container such as bags, jars, etc. The timing hopper 32 receives the product or articles discharged from the combination of weighing pans 22 and 30 obtaining a weight within a specified target weight interval. In the situation where any combination of weighing pans 22 and 30 does not result in a target weight within the target weight interval, the timing hopper 32 may also function as a rejector by not dispensing the products or articles into the packaging machine beneath, but into another destination, such as a container collecting waste, alternatively a station collecting products or articles for recycling, reuse or redistribution into the weighing and batching machine. In this case any number of weighing pans may be emptied.
The hybrid weigher 10 also includes boxes for electronics 34, 36, such as a computer, power cabling, etc.
The base 38 of the weighing pan 22 is fixated to the frame of the weigher 10 by a number of bolts 54.
The shutter 28 is open by a rod 112 having an end 114 used to push the shutter 28 from an open to a closed position. The rod extends from housing 116, the rod being operated by hydraulics, pneumatics or by an electromotor such as a step-motor.
The conveyor belt feeder further comprises a conveyor belt 118 in a prototype version of the conveyor belt feeder. The conveyor belt 118 is constituted by an endlessly rotating conveyor belt type. The conveyor belt 118 is engaged by two sprocket wheels 120, 122 by a motor, not illustrated. The sprockets 120, 122 are mounted on a rotational axle 124, 126 adapted for being driven by a external motor not illustrated. The base 130 of the conveyor belt feeder 26 is fixated to the frame of the hybrid weigher 10 by an angle hinge 132 in connection with a fixation rod 134 and a number of nuts 136.
As described previously the timing hopper 32 may function as a rejection device, this function may be established by simply discharging the products or articles into a receptacle in the packaging machine and subsequently marking that specific receptacle in some way indicating that the contents of the receptacle contains a portion of products or articles does not comply with the specified weight interval. The marking may be substituted by some reject mechanism in the underlying packaging machine.
The flaps 136, 138 are operated by at least two reciprocating devices 140,142, such as pneumatically or hydraulically driven piston or jack. The reciprocating devices 140,142 operates the flaps 136,138 by retracting and extending, respectively, the arms 144,146 thereby opening and closing the passage of articles or products through the timing hopper 32.
In the preferred embodiment of the present invention the timing hopper 32 is fastened to underside of the assembling hopper. Alternatively the function of the timing hopper 32 may be integrated into the assembling hopper.
In the presently preferred embodiment of the present invention the number of large weighing pans is six and the number of assembling pans 20 is twelve. The large weighing pans are scattered or distributed between the smaller weighing pans 22, such that two smaller weighing pans 22 are mounted between two large weighing pans. The larger weighing pans 30 are logically and electrically collected in one unit but physically placed among the smaller weighing pans 22 in order to achieve a better flow and weight distribution. In the preferred embodiment of the present invention the large weighing pans 30 are used to collect a large amount of the articles, such as approximately 90% of the weight of the articles to be collected in one batch, the smaller weighing pans 22 are used to collect a smaller amount of articles, such as approx. 2.5% of the target weight. The conveyor belt feeder 26 may be substituted with a helicon conveyor/feed screw, alternatively a very large vibrating feeder in order to achieve a high throughput of articles. The target batch may be formed by emptying one large weighing pan and four smaller weighing pans.
The materials used to form the individual receptacles or bowl may be chosen from the group including stainless steel, anodised steel or the like. The sheets used to form the walls of the receptacles or bowls may be profiled. The profiles being constituted by a plurality of ripples of substantially the same size, alternatively by substantially elliptical holes, or any other geometrical configuration.
The metal sheets may be coated with a sheet of nylon mat or a sheet of rubber mat, or any combination here of, dependent of the characteristics of the product. E.g. a profiled stainless steel plate with polytetrafluoroethene (Teflon™) may be well suited for a weighing and batching machine handling extremely sticky products, such as dates, while a smooth stainless steel sheet with rubber mat may be employed in machines handling highly fragile products such as cookies. A stainless steel sheet with nylon mat may be employed in machines handling hard objects such as nails and screws.
The pans may have a variety of sizes, again, dependant of the application and the size of the articles or products to be handled. A small pan of e.g. 900 cc may be used to handle products as small as 1 mm each, while a pan of 5500 cc may be used to handle products as large as 300 mm. Larger and smaller pans may, of cause, be envisioned, as well as the number of pans in a weighing and batching machine.
The weighing and batching machine according to the present invention may further be adapted or enhanced for better performance in a specific environment such as in a dusty environment, for example some areas within the confectionery industry, or the weighing and batching machine may be constructed in such a way that it is able to withstand operation in particularly wet and extremely humid environments such as in the fish industry as well as in the vegetable and frozen goods industry.
The multihead weigher may be divided into a number of completely separate product zones in which the weigher may mix the individual products from various product zones into one single batch, e.g. when collecting a batch consisting of frozen peas, carrots and cauliflower.
Furthermore, the weighing and batching machine according to the present invention may be equipped with digital correction technology for increasing the reliability and/or the accuracy of the measurements by eliminating vibrations caused by external sources which may influence the highly sensitive cells on the weighing and batching machine. A control unit may be employed to eliminate these external influences by performing continuous weighing and not reading the average weight for a certain period of time until the weigher is completely at rest. As a result, external vibrations and shocks will appear clearly and will be sorted out.
Based on the expected average weight of the product the calculation unit in the weighing and batching machine may include a program for determining the number of articles with a very high degree of accuracy. The accuracy of course depends on the homogeneity of the product, however, since the number of articles is determined on the basis of the weight of the portion in the individual pans rather than the total weight, standard deviations and thus the possibility of counting errors are reduced to a minimum.
| Number | Date | Country | Kind |
|---|---|---|---|
| 03388060.0 | Sep 2003 | EP | regional |
| Filing Document | Filing Date | Country | Kind | 371c Date |
|---|---|---|---|---|
| PCT/DK04/00600 | 9/10/2004 | WO | 9/21/2006 |
