IES930206A2 - A method for weighing ingredients for animal feed - Google Patents

Abstract

A method for delivering and weighing M ingredients for animal feed. The ingredients are stored in K bins, and M is less than or equal to K. Ingredients are metered through metering augers (10) from the appropriate bins (3) sequentially from bin 1 to bin K onto a main conveyor (8). The main conveyor (8) delivers the ingredients into a weighing hopper (4) where they are cumulatively weighed. Account is taken of the ingredient in transit on the main conveyor (8). Provision is also made to delay delivery of an ingredient from a bin (3) N until the ingredient from the bin (3) N-l has been weighed in the weighing hopper (4).

Description

A method for weighing ingredients for animal feed A method for delivering and weighing M ingredients for animal feed. The ingredients are stored in K bins, and M is less than or equal to K. Ingredients are metered through metering augers (10) from the appropriate bins (3) sequentially from bin 1 to bin K onto a main conveyor (8). The main conveyor (8) delivers the ingredients into a weighing hopper (4) where they are cumulatively weighed. Account is taken of the ingredient in transit on the main conveyor (8). Provision is also made to delay delivery of an ingredient from a bin (3) N until the ingredient from the bin (3) N-l has been weighed in the weighing hopper (4).

Fig. 1 to accompany Abstract MWJCKMN TRUE COPY Λ Γ I /. j 1 DOT |flpthod|for weighing ingredients for animal feed The invention relates to a method for delivering ingredients from a plurality of storage bins and weighing the ingredients, and in particular, though not limited, to a method for weighing ingredients for an animal feed ration.

According to the invention, there is provided a method for delivering M ingredients from a plurality of respective storage means, namely, K storage means, where M and K are integers equal to or greater than 2, M being less than or equal to K, and weighing the M ingredients in a weighing means, at least some of the storage means being remote from the weighing means, the storage means being numbered from one to K in order of their distance from the weighing means, the remote storage means communicating with the weighing means through conveying means, a metering means being provided from each storage means for metering ingredients from the storage means to the conveying means, and control means being provided for controlling the metering means, the method comprising the (a) steps of : assigning each storage means a respective intransit weight factor corresponding to the weight of the ingredient of that storage means to IE 930206 OPEN TO PUBLIC INSPECTION UNDER SECTION 28 AND RULE 23 JNL No../.7/.3.........73 IE 930206 be supported on the conveying means between that storage means and the weighing means, (b) storing the intransit weight factors in the control means, (c) assigning each storage means an inflight time factor which corresponds to the difference between the time it takes an ingredient to settle in the weighing means after all the ingredient has been delivered into the weighing means so that a settled weight can be read from the weighing means and the time it takes a point on the conveying means to travel from that storage means to the next immediate storage means nearer to the weighing means, (d) storing the inflight time factors in the control means, (e) identifying the ingredients by their storage means number (f) setting N, the number of the storage means equal to 1, (g) reading the weight of the ingredient of storage means N required, namely the target weight of the ingredient of storage means N, (h) reading the intransit weight factor of the storage means N, (i) reading the inflight time factor of the storage means N, IE 930206 (j) if N is equal to 1, operating the metering means of the storage means N, (k) if N is greater than 1, timing down the intransit time factor, and then operating the metering means of the storage means N, (l) reading the weighing means until the read weight of the weighing means is equal to the target weight less the intransit weight factor, (m) stopping the metering means of the storage means N, (n) checking if the weighing means has reached a steady state and the settled weight of the ingredient just delivered into the weighing means has been weighed, and (o) carrying out steps (g) to (o) in respect of the ingredient in storage means N + 1 until all M ingredients have been weighed.

In one embodiment of the invention K is greater than M, the target weights of the ingredients in the storage means which are not required being set to 0, the method further comprising the step of checking if the target weight of an ingredient in any storage means is equal to 0, and if so, incrementing N by 1 and returning to step (g).

In a further embodiment of the invention the method IE 930206 further comprises the steps of assigning a time factor to each storage means, the time factor corresponding to the time required by the metering means to meter a unit quantity of the ingredient from that storage means, checking if the target weight of an ingredient is less than the intransit weight factor of the bin containing the ingredient, prior to carrying out step (j), if the target weight is greater than the intransit weight factor continuing with steps (j) to (o) for storage means N, otherwise, reading the time factor for the storage means N, computing the time for which the metering means of storage means N is to be operated to meter the target weight of ingredients, operating the metering means of the storage means N for the computed time, and continuing with steps (m) to (o).

Additionally, the invention provides an animal feed ration comprising a plurality of ingredients mixed together, the ingredients having been delivered from a plurality of storage means and weighed in a weighing means using the method according to the invention.

The invention will be more clearly understood from the following description of a preferred embodiment thereof, given by way of example only, with reference to the accompanying drawings, in which: IE 930206 Fig. 1 is a diagrammatic illustration of apparatus for carrying out the method according to the invention for delivering ingredients from a plurality of storage bins and weighing the ingredients.

Figs. 2(a) and 2(b) is a flowchart of method step of the method according to the invention.

Referring to the drawings, and initially to Fig. 1, there is illustrated apparatus indicated generally by 10 the reference numeral 1 for carrying out a method according to the invention for weighing a plurality of ingredients for subsequent mixing. The apparatus 1 is particularly suitable for mixing a plurality of ingredients for use in the preparation of animal feed 15 rations. The apparatus 1 comprises a plurality of storage means, namely, storage bins 3 for storing ingredients for the animal feed. In this embodiment of the invention, the apparatus 1 comprises K storage bins 3, K being equal to thirty, thus the apparatus 1 comprises thirty storage bins 3, although, for convenience, in Fig. 1 only seven storage bins 3 are illustrated. For ease of identifying the individual storage bins 3, they are identified by the reference numerals 3-1 to 3-30.

IE 930206 Weighing means for weighing the ingredients from the storage bins 3 comprises a weighing hopper 4. Weighed ingredients are delivered from the weighing hopper 4 through a hopper outlet valve 5 into a mixing unit, namely, a paddle mixer 6. The paddle mixer 6 in which the ingredients of the ration are mixed is mounted beneath the weighing hopper 4, and the weighed ingredients are delivered from the weighing hopper 4 into the paddle mixer 6 under gravity.

Conveying means, in this case a main chain conveyor 8 communicates the storage bins 3-2 to 3-30 with the weighing hopper 4 for delivering ingredients from the storage bins 3-2 to 3-30 to the weighing hopper 4. Metering means, namely, metering augers 10 extend from outlets 9 of respective storage bins 3-2 to 3-30 for metering the ingredients from the respective storage bins 3-2 to 3-30 onto the main chain conveyor 8. The rates at which the respective metering augers meter the ingredients from the respective bins 3-1 to 3-30 is known. The storage bin 3-1 is mounted directly over the weighing hopper 4, and accordingly, communicates directly with the weighing hopper 4 through its associated metering auger 10. The storage bins 3-2 to 3-30 are mounted remotely of the weighing hopper 4 and are numbered 2 to 30 in ascending order in the order of their distance from the weighing IE 930206 hopper 4. In other words, the storage bin 3-2 is nearest the weighing hopper 4, while the storage bin 3-30 is furthest away from the weighing hopper 4. The distance of the farthest storage bin 3-30 from the weighing hopper 4 may be as much as 50 meters and in certain cases more. In this embodiment of the invention the ingredients are delivered to the weighing hopper 4 from the storage bins 3 sequentially in ascending bin number order. The ingredients are cumulatively weighed on completion of delivery of each ingredient into the weighing hopper 4. On all the ingredients of the animal feed ration being weighed in the weighing hopper 4, the weighed ingredients are then delivered through the outlet valve 5 into the paddle mixer 6 for mixing.

Electrically powered motors (not shown) are provided for powering the mixer 6 and the main conveyor 8. Respective electrically powered motors (also not shown) are provided for powering the metering augers . An electrically powered motor (also not shown) operates the outlet valve 5 from the weighing hopper 4. All the electrically powered motors are operated under the control of suitable control circuitry (not shown) which in turn is operated under the control of a computer (not shown). A computer programme controls the computer (not shown) for operating the apparatus IE 930206 1. A flow chart of part of the computer programme for operating the apparatus 1 for delivering all the ingredients of a feed ration from the storage bins 3 into the weighing hopper 4 and weighing the ingredients in the weighing hopper 4 is illustrated in Figs. 2a and 2b and will be described in detail below. This is the part of the computer programme which is most relevant to the method of the invention.

Load cells (also not shown) are provided in the 10 weighing hopper 4 for weighing the contents thereof.

Such load cells will be well known to those skilled in the art. The load cells are connected to the control circuity (not shown) and the outputs from the load cells are read by the computer under the control of the computer programme, the flow chart of part of which is illustrated in Figs. 2a and 2b.

The apparatus 1 is suitable for selecting and weighing M ingredients from the storage bins 3-1 to 3-K. M being an integer from 2 to K. In general, M will be less than K, although, in certain cases, M may be equal to K, in which case, ingredients from all the storage bins 3-1 to 3-K would be included in the animal feed ration.

The weight of each ingredient required in an animal IE 930206 feed ration for convenience will be referred to hereinafter as the target weight of the ingredient.

As mentioned above the ingredients are cumulatively weighed in the weighing hopper 4 after completion of delivery of each ingredient in the weighing hopper 4. In order that the weight is accurately read after completion of delivery of each ingredient into the weighing hopper 4, a settling period is allowed before the weight of the ingredient or ingredients in the weighing hopper 4 is read and recorded by the computer programme. This time period is referred to hereinafter as the settling time, and it is the time which elapses between completion of delivery of an ingredient into the weighing hopper 4, and the time the weight read by the computer is recorded as being the weight of the ingredient or ingredients in the weighing hopper 4. In this embodiment of the invention the settling time is approximately three seconds. The weight which is read at the end of the settling period is referred to hereinafter as the settled weight. Since the ingredients are cumulatively weighed, the settled weight of an ingredient is determined by subtracting from the cumulative settled weight recorded after that ingredient has been delivered into the weighing hopper 4, the cumulative settled weight recorded after the previous ingredient had been delivered into the IE 930206 weighing hopper 4. Thus, throughout this specification where reference is made to the settled weight of an ingredient, the reference refers to the settled weight of that ingredient only. The computations to provide this settled weight are carried out by the computer.

To avoid the need to wait for the settled weight of an ingredient to be weighed by the weighing hopper 4 before the next ingredient is delivered from the next appropriate storage bin 3, an inflight time factor is assigned to each storage bin 3-2 to 3-30. The inflight time factor of each storage bin 3-N is computed by deducting from the settling time, the time taken for a point on the main chain conveyor 8 to travel between the storage bin 3-N and 3-N-l.

To ensure that the settled weight is substantially equal to the target weight for each ingredient, an intransit weight factor is assigned to each storage bin 3. The intransit weight factor for each bin 3-N is the weight of the ingredient in transit between the storage bin 3-N and the weighing hopper 4 supported on the main chain conveyor 8.

To cater for a situation where the target weight of an ingredient required is less than the intransit weight IE 930206 factor of the storage bin 3 of the ingredient, in other words, where the weight of the ingredient on the main chain conveyor 8 in transit between the storage bin 3-N and the weighing hopper 4, a time factor is assigned to each storage bin 3. The time factor of each storage bin 3-N is the time which would be taken by the metering auger 10 of that storage bin 3-N to meter a unit weight of ingredient. In this case, the time factor is given as the time required to meter ten kilos of the ingredient from the respective storage bins 3. These three factors, namely, the inflight time factor, the intransit weight factor and the time factor of each storage bin 3-N are stored in the computer memory and are read by the computer programme which controls the operation of the apparatus 1.

Batches of the various animal feed rations are produced by the apparatus 1 according to recipes for the respective animal feed rations. The recipes are stored in the computer, and batches of predetermined quantities of the respective feed rations are produced. The target weights of the respective ingredients for appropriate batch sizes of each animal feed ration are stored with the recipes in the computer. The ingredients are identified by their storage bin number, namely, 3-1 to 3-30. The target weights are set against the bin number for the IE 930206 respective animal feed rations and batch sizes. Where an animal feed ration does not require one or more of the ingredients, the target weight of that ingredient is stored as zero weight. A suitable computer programme not described is provided for enabling the target weights of the various ingredients of the respective animal feed rations to be entered into the computer initially and stored. Further, this computer programme permits the target weights of ingredients of animal feed rations already entered to be altered. Provision is also made in this programme to enable additional feed ration recipes to be entered into the computer. This computer programme also permits the recipe of an animal feed ration to be selected. Once the recipe of the animal feed ration has been selected, the computer programme, the flow chart of which is illustrated in Figs. 2a and 2b controls the apparatus 1 for delivering the required ingredients to the weighing hopper 4 and for weighing the ingredients in the weighing hopper 4 of the selected animal feed ration as follows.

Block 1 of the computer programme assigns a value 1 to a variable Y. The variable Y will be described in more detail as the programme is described. Block 2 sets N equal to 1. N is an integer from 1 to K and represents the storage bin number from which an IE 930206 ingredient is required. By setting N equal to 1 the first storage bin, namely storage bin 3-1 is selected. Block 3 reads the target weight of the ingredient of the bin 3-N which is required. This is read from the selected recipe of the animal feed ration. Block 4 checks if the target weight of the ingredient of the storage bin 3-N is equal to 0. If the target weight of the ingredient of the storage bin 3-N is equal to 0, the computer programme moves to block 5, which increments N by 1 and returns to block 3. The computer programme remains in this loop until the target weight of the ingredient of the storage bin 3-N is not equal to 0. At that stage, the computer programme moves to block 6. Block 6 checks if the target weight of the ingredient of storage bin 3-N which is required is less than the intransit weight factor for the storage bin 3-N. If the target weight of the ingredient required from storage bin 3-N is not less than the intransit weight factor of the storage bin 3-N, the programme moves to block 7. Otherwise, the programme moves to block 8. Block 8 and the subsequent blocks following on from block 8 are described below with reference to Fig. 2(b).

Returning to block 7, block 7 computes a stop weight for the ingredient of the storage bin 3-N. The stop weight is computed by subtracting the intransit weight factor of the bin 3-N from the target weight of the IE 930206 ingredient of the storage bin 3-N. The stop weight is used by the computer programme for stopping the metering means of the storage bin 3-N to allow for the ingredient in transit on the main conveyor 8. Thus the stop weight is the weight which, when read from the load cells (not shown) of the weighing hopper 4 is the weight at which a signal is delivered to the metering auger 10 of the storage bin 3-N to switch off the motor (not shown) of that metering auger 10. In this way when the remainder of the ingredient from the storage bin 3-N on the main chain conveyor 8 is delivered into the weighing hopper 4, the settled weight of the ingredient of the bin 3-N in the weighing hopper 4 should be equal to the target weight. On the stop weight having been computed, the computer programme moves to block 9, which checks if the inflight time factor is equal to 0. If the inflight time factor of the bin 3-N is not equal to 0, the computer programme moves to block 10, which times down the inflight time factor. When the computer programme has timed down the inflight time factor, the computer programme moves to block 11. Block 11 switches on the motor (not shown) of the metering auger 10 of the storage bin 3-N for delivering the ingredient from the storage bin 3-N to the main chain conveyor 8 which is continuously moving. Should block 9 determine that the inflight time factor is equal to IE 930206 0, the programme moves to block 12 which checks if Y is equal to 1. If Y is equal to 1, the programme moves to block 11, which has already been described.

If block 12 determines that Y is not equal to 1, the programme moves to block 13, which waits until a steady state is achieved in the weighing hopper 4, in other words, until the settling time has elapsed, since delivery of the last ingredient into the weighing hopper 4 has been completed. This may be the ingredient from the bin 3-N-l or a storage bin of any number less than N. Block 13 then reads the settled weight of the ingredient, the delivery of which has already been completed from the load cells of the weighing hopper 4. The programme then moves to block 11. After block 11, the computer programme moves to block 14, which checks that Y is equal to 1. If Y is equal to 1, the programme moves to block 15, which reads the weight output from load cells of the weighing hopper 4. If block 14 determines that Y is not equal to 1, the computer programme moves to block 16, which waits until the settling time has elapsed since delivery of the last ingredient into the weighing hopper 4 has been completed, and block 16 then reads the settled weight of the ingredient from the load cell of the weighing hopper 4. The computer programme then moves to block 15. In both blocks 13 and 16, as well as reading the settled weights of the IE 930206 previous ingredient to have been delivered into the weighing hopper 4, blocks 13 and 16 also store the settled weight read from the load cell of the weighing hopper 4. These settled weights can be used by the computer programme for updating the intransit weight factors for the respective storage bins 3.

After block 15, the computer programme moves to block 18, which compares the weight read from the load cells of the weighing hopper 4 with the stop weight. If the read weight is less than the stop weight, the programme returns to block 15 and remains in this loop until the read weight is equal to or greater than the stop weight, at which stage the programme moves to block 19. Block 19 switches off the motor (not shown) of the metering auger 10 of the storage bin 3-N, thereby preventing further discharge of ingredient from the storage bin 3-N. The main chain conveyor 8 continues delivering the ingredient from the storage bin 3-N until all the ingredient on the main chain conveyor 8 has been delivered to the weighing hopper 4. The programme then moves to block 20, which sets Y equal to 2 and in turn moves to block 21, which increments N by 1. The programme then moves to block 31, which checks if N is less than or equal to K. If N is less than or equal to K, the computer programme returns to block 3, otherwise, the computer programme IE 930206 ends, since all M ingredients have been weighed.

Returning now to block 8 and referring to Fig. 2(b), block 8 computes the time period for which the metering auger 10 of the storage bin 3-N is to be operated in order to deliver the target weight of the ingredient of the bin 3-N. The time period is computed from the time factor of the storage bin 3-N.

Block 8 reads the time factor of the storage bin 3-N and determines the time period by multiplying the time factor, by the target weight required. In this case, since the time factor is given as the time to deliver ten kilograms of ingredient, the time period is determined by multiplying the target weight of the ingredient from the bin 3-N required by the time factor and then dividing the product by ten. Having determined the time period, the computer programme moves to block 22, which checks if the inflight time for the storage bin 3-N is equal to 0. If not, the computer programme moves to block 23, which times down the inflight time factor for the bin 3-N and then moves to block 24, which switches on the motor (not shown) of the metering auger 10 of the storage bin 3-N, for delivering the ingredient from the bin 3-N to the main chain conveyor 8 and in turn to the weighing hopper 4. In the event that block 22 determines that the inflight time is equal to 0, the computer IE 930206 programme moves to block 25, which checks if Y is equal to 1. If Y is equal to 1, the computer programme moves to block 24, which has already been described. If Y is not equal to 1, the computer programme moves to block 26, which is similar to blocks 13 and 16, in other words, block 26 waits until the settling time has elapsed and reads the settled weight of the ingredient to have been previously delivered into the weighing hopper 4. Block 26 stores the read settled weight of the last ingredient to be delivered into the weighing hopper 4 in similar fashion as blocks 13 and 16. The computer programme then moves to block 24 which has already been described. After block 24 the computer programme moves to block 27 and times down the time period during which the ingredient is to be delivered from the storage bin 3-N. In other words, block 27 times the period for which the metering auger 10 of the storage bin 3-N is to operate. On block 27 having timed down the time period, the computer programme moves to block 28 which immediately switches off the motor of the metering auger 10 of the bin 3-N. This thus prevents further discharge of the ingredient from the bin 3-N. The main chain conveyor 8 continues to operate and accordingly, delivers the ingredient of bin 3-N on the main chain conveyor 8 in to the weighing hopper 4. The computer programme then moves IE 930206 to block 29 which sets Y equal to 2, and in turn moves to block 30 which increments N by 1 and then moves to block 31.

The variable Y is used to determine whether the 5 storage bin 3-N is the first storage bin from which ingredients are being delivered to the weighing hopper 4. If the storage bin 3-N is the first storage bin to deliver an ingredient to the weighing hopper 4, the value of Y will be 1, and in which case, there will be no need to delay delivery of the ingredient from that bin 3 with the first ingredient. In other words, there will be no need to wait or check if a steady state has been achieved in the weighing hopper 4, since no ingredients will have been delivered into the weighing hopper 4. Accordingly, in the event of Y being equal to 1, the computer programme immediately commences delivery of the ingredient from the storage bin 3-N. However, once the first ingredient has been delivered into the weighing hopper 4, the value of Y is set at 2. In which case, where necessary, the computer programme checks if a steady state has been reached in the weighing hopper 4. This is required in the case of a storage bin 3 which is feeding directly into the weighing hopper 4.

On all M ingredients having been weighed in the IE 930206 weighing hopper 4, the outlet valve 5 of the weighing hopper 4 is opened, and the ingredients in the weighing hopper 4 are discharged into the mixer 6 for mixing and further processing under the control of the computer programme.

While in the embodiment of the invention described, the apparatus has been described as comprising one main chain conveyor communicating the storage bins with the weighing hopper, in many cases, it is envisaged that a number of main chain conveyors may be provided, in which case, each main chain conveyor would normally service a number of storage bins. It will of course be appreciated that while it is preferable that the conveying means would be provided with a chain conveyor or chain conveyors, any other suitable conveying means may be provided.

Further, while each storage bin has been described as being provided with a metering auger for metering the ingredient any other suitable metering means may be used. Indeed, in many cases, it is envisaged that the ingredients may be delivered onto the main chain conveyor by gravity from the storage bins through suitable outlet valves. In such cases, it is envisaged that the outlet valves from the storage bins would be operated in similar fashion by the computer IE 930206 programme of Figs. 2a and 2b as the metering augers.

While the outlet valve of the weighing hopper has been described as being motor operated, it may be operated by any other suitable means, for example, it may be solenoid operated, operated by a pneumatic or hydraulic ram or operated by any other suitable means.

The invention is not limited to the embodiment hereinbefore described which may be varied in construction and detail.

Claims (5)

1. A method for delivering M ingredients from a plurality of respective storage means, namely, K storage means, where M and K are integers equal to or 5 greater than

2. , M being less than or equal to K, and weighing the M ingredients in a weighing means, at least some of the storage means being remote from the weighing means, the storage means being numbered from one to K in order of their distance from the weighing 10 means, the remote storage means communicating with the weighing means through conveying means, a metering means being provided from each storage means for metering ingredients from the storage means to the conveying means, and control means being provided for 15 controlling the metering means, the method comprising the steps of : (a) assigning each storage means a respective intransit weight factor corresponding to the weight of the ingredient of that storage means to 20 be supported on the conveying means between that storage means and the weighing means, (b) storing the intransit weight factors in the control means, (c) assigning each storage means an inflight time 25 factor which corresponds to the difference between the time it takes an ingredient to settle in the weighing means after all the ingredient IE 930206 has been delivered into the weighing means so that a settled weight can be read from the weighing means and the time it takes a point on the conveying means to travel from that storage means to the next immediate storage means nearer to the weighing means, (d) storing the inflight time factors in the control means, (e) identifying the ingredients by their storage means number (f) setting N, the number of the storage means equal to 1, (g) reading the weight of the ingredient of storage means N required, namely the target weight of the ingredient of storage means N, (h) reading the intransit weight factor of the storage means N, (i) reading the inflight time factor of the storage means N, (j) if N is equal to 1, operating the metering means of the storage means N, (k) if N is greater than 1, timing down the intransit time factor, and then operating the metering means of the storage means N, (l) reading the weighing means until the read weight of the weighing means is equal to the target weight less the intransit weight factor, IE 930206 (m) stopping the metering means of the storage means N, (n) checking if the weighing means has reached a steady state and the settled weight of the 5 ingredient just delivered into the weighing means has been weighed, and (o) carrying out steps (g) to (o) in respect of the ingredient in storage means N + 1 until all M ingredients have been weighed. 10 2. A method as claimed in Claim 1 in which K is greater than M, the target weights of the ingredients in the storage means which are not required being set to 0, the method further comprising the step of checking if the target weight of an ingredient in any 15 storage means is equal to 0, and if so, incrementing N by 1 and returning to step (g).

3. A method as claimed in Claim 1 or 2 in which the method further comprises the steps of assigning a time factor to each storage means, the time factor 20 corresponding to the time required by the metering means to meter a unit quantity of the ingredient from that storage means, checking if the target weight of an ingredient is less than the intransit weight factor of the bin containing the ingredient, prior to 25 carrying out step (j), if the target weight is greater IE 930206 than the intransit weight factor continuing with steps (j) to (o) for storage means N, otherwise, reading the time factor for the storage means N, computing the time for which the metering means of storage means N 5 is to be operated to meter the target weight of ingredients, operating the metering means of the storage means N for the computed time, and continuing with steps (m) to (o).

4. A method for delivering M ingredients from a 10 plurality of respective storage means and weighing the ingredients in a weighing means, the method being substantially as described herein with reference to and is illustrated in the accompanying drawings.

5. An animal feed ration comprising a plurality of 15 ingredients mixed together, the ingredients having been delivered from a plurality of storage means and weighed in a weighing means using the method of any of Claims 1 to 4.