GB2093609A - Method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off - Google Patents
Method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off Download PDFInfo
- Publication number
- GB2093609A GB2093609A GB8205000A GB8205000A GB2093609A GB 2093609 A GB2093609 A GB 2093609A GB 8205000 A GB8205000 A GB 8205000A GB 8205000 A GB8205000 A GB 8205000A GB 2093609 A GB2093609 A GB 2093609A
- Authority
- GB
- United Kingdom
- Prior art keywords
- filling
- time
- balance
- switched
- stream
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 238000000034 method Methods 0.000 title claims abstract description 16
- 239000000463 material Substances 0.000 title claims abstract description 15
- 238000005303 weighing Methods 0.000 claims abstract description 20
- 239000000523 sample Substances 0.000 claims abstract description 8
- 238000005429 filling process Methods 0.000 description 4
- 239000013590 bulk material Substances 0.000 description 3
- 230000001419 dependent effect Effects 0.000 description 3
- 238000010586 diagram Methods 0.000 description 1
- 238000001595 flow curve Methods 0.000 description 1
- 235000020825 overweight Nutrition 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G13/00—Weighing apparatus with automatic feed or discharge for weighing-out batches of material
- G01G13/02—Means for automatically loading weigh pans or other receptacles, e.g. disposable containers, under control of the weighing mechanism
- G01G13/12—Arrangements for compensating for material suspended at cut-off, i.e. for material which is still falling from the feeder when the weigher stops the feeder
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01G—WEIGHING
- G01G13/00—Weighing apparatus with automatic feed or discharge for weighing-out batches of material
- G01G13/24—Weighing mechanism control arrangements for automatic feed or discharge
- G01G13/30—Weighing mechanism control arrangements for automatic feed or discharge involving limit switches or position-sensing switches
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Weight Measurement For Supplying Or Discharging Of Specified Amounts Of Material (AREA)
- Basic Packing Technique (AREA)
Abstract
A method for automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off makes use of a probe (1), whereby the actual weight (m) in the weighing vessel is ascertained, either continuously or discontinuously at short intervals of time, during the filling period. The readings are fed via an amplifier (2) to a computer (3) and an interpreting device (4). In the computer (3) the filling speed <dm>/dt and then the precise flow lead K x <dm>/dt are calculated, K being a time constant specific to the balance in question. The computer values are fed to the interpreting device (4), which switches off the filling stream by means of a control signal, as soon as the sum of the actual weight and the computed flow lead is equal to the desired weight of material to be weighed out. <IMAGE>
Description
SPECIFICATION
Method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off
The invention relates to a method of automatically adjusting the time at which a filling stream of material fed to an electro-mechanical balance is switched off.
Electromechanical balances are known for weighing out granular or granulated bulk materials with varying grain size, varying bulk weight and varying flow properties and usually comprise a weighing vessel suspended from a weighing mechanism which controls the feed of bulk material dependent on the weight.
The bulk material is generally initially fed to the weighing vessel as a course flow. After the fine flow has been cut off, material downstream of the cut off point continues to move forward and must thus be allowed for if the final weight is to be equal to the desired weight.
It is known to ascertain the fine flow lead empirically, i.e. the difference in weight between the desired value and the actual weight at the time when the fine flow is switched off. The lead is corrected when weighing has taken place, if there is any deviation from the desired weight, i.e. if the material is under or over weight. The correction may be made manually or by means of an automatic controller for the follow-up flow.
It is a disadvantage that the correction of the precise flow lead cannot be initiated until incorrectly weighed material has been discarded.
The invention has among its objects to provide a method whereby, with a given desired value for the filling weight, the switching off time for the filling stream or the filling stream lead existing at the switching off time can be determined dependent on the course of the filling process.
According to one aspect of the invention, there is provided a method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off, comprising using a probe to ascertain the actual weight m in a weighing vessel of the balance, either continuously or discontinuously at short intervals of time, during a filling period; using a computer to calculate the filling speed dm/dt and then the precise flow lead K x dm/dt, where K is a time constant specific to the balance; feeding the values m dm/dt and K x dm/dt to an interpreting device; and causing the interpreting device to issue a control signal to switch off the filling stream as soon a the sum of the actual weight and the computed precise flow lead is equal to the weight desired to be weighed out by the weighing operation.
According to another aspect of the invention, there is provided not only a first probe which ascertains the actual weight in the weighing vessel, either continuously or discontinuously at short intervals of time during the filling period, but also a second probe which measures the filling speed dm/dt.
In previously proposed methods it is only after the weighing operation has been completed that there is a check as to whether the actual weight obtained is the same as the desired weight, or whether there are any deviations from the desired weight beyond the tolerance range, which would make it necessary to discard the material weighed before correcting ready for the next weighing operation. In the method of the invention on the other and, the time at which the filling stream has to be switched off is acertained while the weighing vessel is being filled during each weighing operation.Changes in the increase in mass per unit of time, i.e. in the filling speed during the filling operation, are according to the invention determined by measuring techniques or by means of a process computer; these values, which determine the filling process, can therefore be used to stipulate the time at which the filling stream has to be switched off.
The method of the invention can avoid the need to discard incorrectly weighed material.
The invention is diagrammatically illustrated by way of example with reference to the accompanying drawings:
In Figure 1 a filling stream, which is being fed to the weighing vessel of an electromechanical balance, is represented in the form of a graph. Mass m is plotted on the ordinate and filling time ton the abscissa.
Figure 2 shows the inrease in mass (filling speed) dm/dt during the filling time t.
In Figure 3 the mass m is plotted on the ordinate and the filling time ton the absciss. The drawing shows the filling stream curve, the desired weight S and the filling stream lead K x dm/dt, the time constant K being a value specific to the particular balance being used.
In the drawing, the switching off time for the coarse flow is shown at t1 and that for the fine flow at t2. The fine flow curve and the curve of the filling stream lead intersect at the switching off time for the fine flow in
Figure 3.
In the method of the invention the switching off time is ascertained during the filling process.
The apparatus required for this purpose is shown diagrammatically in Figure 4, in the form of a block circuit diagram. Reference 1 denotes a probe, whereby the actual mass m in the weighing vessel of the balance is ascertained, either continuously or discontinuously at short intervals of time, during the filling period. The signals thereby generated are fed via an amplifier 2 to a computer 3 and an interpreting device 4.
In the computer 3 the filling speed dm/dt and then the precise flow lead K x dm/dt are ascertained from the signals. The values computed are transferred to the interpreting device, which switches off the filling stream by means of a control signal, as soon as the sum of the actual weight and the calculated precise flow lead is equal to the desired weight.
The filling stream curve for the bulk material being fed to the weighing vessel may be made up of a coarse flow portion and a fine flow portion or a coarse, fine and very fine flow portion. Other filling stream curves are also possible.
The method of the invention, for ascertaining the optimum switching off time for the filling stream, is applicabie to all filling processes and is not dependent on any particular shape of the filling stream curve.
Claims (3)
1. A method of automatically adjusting the time at which a filling stream of material fed to an electrochemical balance is switched off, comprising using a probe to ascertain the actual weight m in a weighing vessel of the balance, either continuously or discontinuously at short intervals of time, during a filling period; using a computer to calculate the filling speed dm/dt and then the precise flow lead K x dm/dt, where K is a time constant specific to the balance; feeding the values m, dm/dt and K x dm/dt to an interpreting device; and causing the interpreting device to issue a control signal to switch off the filling stream as soon as the sum of the actual weight and the computed precise flow lead is equal to the weight desired to be weighed out by the weighing operation.
2. A method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off, comprising using a first probe to ascertain the actual weight m in a weighing vessel of the balance, either continuously or discontinuously at short intervals of time during a filling period; using a second probe simultaneously to measure the filling speed dm/dt; calculating the precise flow lead K x dm/dt in a computer, where K is a time constant specific to the balance; feeding the values m, dm/dt and K x dm/dttO an interpreting device; and causing the interpreting device to issue a control signal to switch off the filling stream as soon as the sum of the actual weight, m and the computed precise flow lead, K x dm/dt is equal to the weight desired to be weighed out by the weighing operation.
3. A method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balance is switched off substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DE3106473A DE3106473A1 (en) | 1981-02-21 | 1981-02-21 | "METHOD FOR AUTOMATICALLY ADJUSTING THE DISCONNECTING POINT OF THE FILLING FLOW OF AN ELECTROMECHANICAL SCALE" |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2093609A true GB2093609A (en) | 1982-09-02 |
| GB2093609B GB2093609B (en) | 1984-06-06 |
Family
ID=6125407
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8205000A Expired GB2093609B (en) | 1981-02-21 | 1982-02-19 | Method of automatically adjusting the time at which a filling stream of material fed to an electromechanical balnce is switched off |
Country Status (8)
| Country | Link |
|---|---|
| AU (1) | AU7962882A (en) |
| BE (1) | BE891995A (en) |
| DE (1) | DE3106473A1 (en) |
| FR (1) | FR2500624A1 (en) |
| GB (1) | GB2093609B (en) |
| IT (1) | IT1157634B (en) |
| SE (1) | SE8201050L (en) |
| ZA (1) | ZA821094B (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0092410A2 (en) * | 1982-04-21 | 1983-10-26 | Haigh Chadwick Limited | Cyclically weighing bulk solid material |
| FR2544492A1 (en) * | 1983-04-18 | 1984-10-19 | Manurhin | METHOD AND DEVICE FOR PONDERALLY DOSING A POWDER |
| GB2155645A (en) * | 1984-03-03 | 1985-09-25 | Haver & Boecker | Filling bags |
| FR2693549A1 (en) * | 1992-07-07 | 1994-01-14 | Pack Realisations | Automatic control of filling levels - by variation of delay time between supplying closure signal to filling head and actual closure time |
| WO1997021590A1 (en) * | 1995-12-12 | 1997-06-19 | Kao Corporation | Method and apparatus for filling bulk material |
| EP1947427A1 (en) * | 2007-01-19 | 2008-07-23 | Mettler-Toledo AG | Method for optimising dosage processes and dosage device |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3127131C2 (en) * | 1981-07-09 | 1983-09-29 | Behn Maschinenfabrik GmbH & Co KG, 4150 Krefeld | Process and device for the gravimetric filling of containers and sacks in coarse and fine flow |
| DE3708078A1 (en) * | 1987-03-13 | 1988-09-22 | Rovema Gmbh | METHOD AND DEVICE FOR THE AUTOMATIC GRAVIMETRIC FILLING OF BULK MATERIAL AND / OR LIQUID |
| DE4100658C2 (en) * | 1991-01-11 | 1995-01-05 | Haver & Boecker | Method and machine for introducing flowable filling material into containers |
Family Cites Families (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US2933281A (en) * | 1955-04-01 | 1960-04-19 | Proctor & Schwartz Inc | Apparatus for supplying a desired weight of material to a receiving receptacle |
| GB853605A (en) * | 1959-02-23 | 1960-11-09 | Lancashire Dynamo Electronic P | Improvements in apparatus for controlling the delivery of measured quantities of material |
| FR2146152B1 (en) * | 1971-07-21 | 1974-09-27 | Trayvou Sa | |
| CH559353A5 (en) * | 1972-11-08 | 1975-02-28 | Buehler Ag Geb | Automatic delivery and weighing of material from silos - with digital computing equipment comparing actual and required values |
| FR2384246A1 (en) * | 1977-03-18 | 1978-10-13 | Rhone Poulenc Ind | Powdered material dosage meter - has hopper and Archimedean screw regulated to give constant flow of prod. |
| DE2903259C2 (en) * | 1979-01-29 | 1986-04-10 | Carl Schenck Ag, 6100 Darmstadt | Process for dosing materials with changing flow properties |
-
1981
- 1981-02-21 DE DE3106473A patent/DE3106473A1/en not_active Withdrawn
-
1982
- 1982-01-19 AU AU79628/82A patent/AU7962882A/en not_active Abandoned
- 1982-02-02 BE BE0/207210A patent/BE891995A/en not_active IP Right Cessation
- 1982-02-18 IT IT12443/82A patent/IT1157634B/en active
- 1982-02-18 FR FR8203083A patent/FR2500624A1/en active Pending
- 1982-02-19 SE SE8201050A patent/SE8201050L/en not_active Application Discontinuation
- 1982-02-19 ZA ZA821094A patent/ZA821094B/en unknown
- 1982-02-19 GB GB8205000A patent/GB2093609B/en not_active Expired
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP0092410A2 (en) * | 1982-04-21 | 1983-10-26 | Haigh Chadwick Limited | Cyclically weighing bulk solid material |
| GB2119938A (en) * | 1982-04-21 | 1983-11-23 | Cosmopolitan Textile Co Ltd | Weighing fluent material |
| EP0092410A3 (en) * | 1982-04-21 | 1984-07-25 | Haigh Chadwick Limited | Cyclically weighing bulk solid material |
| US4552235A (en) * | 1982-04-21 | 1985-11-12 | Haigh Chadwick Limited | Cyclically weighing bulk solid material |
| FR2544492A1 (en) * | 1983-04-18 | 1984-10-19 | Manurhin | METHOD AND DEVICE FOR PONDERALLY DOSING A POWDER |
| EP0126662A1 (en) * | 1983-04-18 | 1984-11-28 | Manufacture De Machines Du Haut-Rhin S.A. (Manurhin) | Process and device for the dosage by weight of a powder |
| GB2155645A (en) * | 1984-03-03 | 1985-09-25 | Haver & Boecker | Filling bags |
| FR2693549A1 (en) * | 1992-07-07 | 1994-01-14 | Pack Realisations | Automatic control of filling levels - by variation of delay time between supplying closure signal to filling head and actual closure time |
| WO1997021590A1 (en) * | 1995-12-12 | 1997-06-19 | Kao Corporation | Method and apparatus for filling bulk material |
| EP1947427A1 (en) * | 2007-01-19 | 2008-07-23 | Mettler-Toledo AG | Method for optimising dosage processes and dosage device |
| CN101251407B (en) * | 2007-01-19 | 2011-10-12 | 梅特勒-托利多公开股份有限公司 | Method for optimising dosage processes and dosage device |
| US8448817B2 (en) | 2007-01-19 | 2013-05-28 | Mettler-Toledo Ag | Method of optimizing dosage-dispensing processes, and dosage-dispensing device |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2500624A1 (en) | 1982-08-27 |
| BE891995A (en) | 1982-05-27 |
| GB2093609B (en) | 1984-06-06 |
| AU7962882A (en) | 1982-09-02 |
| ZA821094B (en) | 1983-02-23 |
| DE3106473A1 (en) | 1982-09-09 |
| SE8201050L (en) | 1982-08-22 |
| IT1157634B (en) | 1987-02-18 |
| IT8212443A0 (en) | 1982-02-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |