Classifications

• • A—HUMAN NECESSITIES
  • A21—BAKING; EDIBLE DOUGHS
  • A21C—MACHINES OR EQUIPMENT FOR MAKING OR PROCESSING DOUGHS; HANDLING BAKED ARTICLES MADE FROM DOUGH
  • A21C5/00—Dough-dividing machines
  • A21C5/02—Dough-dividing machines with division boxes and ejection plungers

Definitions

• the present invention relates to a method and assembly for metering dough by means of a metering device comprising: a hopper for the supply of dough to be metered, a piston that is movable in a first chamber, wherein the first chamber connects to the hopper, a blade member that is also movable in the first chamber and arranged between the piston and the hopper, at least one metering chamber, wherein the metering chamber is adapted for in at least one position connecting to the first chamber, and the metering chamber is movable with respect to the first chamber.
• the quantity of dough processed by the slide per stroke depends on the desired volume ⁇ weight) per recipe.
• the desired volume can be set by bounding the metering pistons during filling the metering chamber(s). When the dough is pushed from the slide into the metering chamber(s) by means of the piston this is done with a force exerting pressure on the dough. This pressure has a negative influence on the dough structure, at least in case of highly sensitive dough types.
• Patent specification NL 1 ,029,361 describes an embodiment of a metering device wherein the piston and the blade member are individually controllable, and a control device for it which defines the suction stroke magnitude on the basis of the set volume of the metering chamber(s), and wherein the ejection stroke magnitude is adapted on the basis of the measured pressure of the dough in the suction chamber in order to let the dough be pressurised as little as possible in order to preserve the quality of the dough as much as possible.
• the suction stroke of the piston is defined by the set volume of the metering chamber, wherein the volume of the suction stroke is an integer number of times the set volume of the metering chamber, whether or not increased by a predetermined buffer volume.
• a drawback thereof is that at least a part of the dough is pressurised several times.
• the invention provides a method for setting a piston stroke magnitude of a metering device of an assembly comprising: a metering device according to the preamble; a weighing device, placed downstream from the metering device, for determining the weight of dough portions coming out of the metering chamber; and a control device coupled to both the metering device and the weighing device, adapted for setting a piston stroke magnitude of the piston, wherein the method is characterised by the following steps: i) setting a series of piston stroke magnitudes for a dough product, ii) carrying out a number of metering strokes per piston stroke magnitude, weighing the dough portions resulting therefrom by the weighing device and determining a standard deviation in weight of those portions, iii) determining the optimal piston stroke magnitude for which the standard deviation in weight of the metered dough portions is minimal, iv) setting the optimal piston stroke of the metering device for the dough product by the control device.
• the magnitude of the suction stroke is optimised here, i.e. that part of the piston stroke during which dough is sucked in. This is because the quantity of dough present in the first chamber also determines how much pressure is exerted on the dough during the ejection stroke.
• Determining the piston stroke magnitude from a limited number of piston stroke magnitudes which leads to the highest accuracy in weight comprises metering a number of dough portions for a number of possible piston stroke magnitudes, after which said portions of dough are weighed on a weighing device. The piston stroke magnitude resulting in dough portions having the smallest standard deviation in weight is then set as the optimal piston stroke magnitude.
• that piston stroke magnitude is chosen for which the quantity of dough in the first chamber is as small as possible, or for which the piston stroke is as small as possible.
• the standard deviation in weight need not necessarily be linearly related to the piston stroke magnitude; besides the quantity of sucked in dough, factors such as dough composition and shape and content of the metering chamber(s) may influence the standard deviation, so that per dough composition for all piston stroke magnitudes a number of metering strokes has to be carried out in order to be able to determine the related optimal piston stroke.
• the optimal piston stroke magnitude from a series of piston stroke magnitudes for a metering machine can be determined quickly and easily.
• step ii) prior to carrying out the number of metering strokes, first one piston stroke is carried out of which the resulting dough portions are ignored in the calculation of the standard deviation. In this way it is ensured that the first chamber is sufficiently filled prior to starting with the optimisation.
• the series of piston stroke magnitudes in step i) can be ranged from small to large, the series of piston stroke magnitudes in step i) preferably are ranged from large to small.
• step iii) each time after the number of metering strokes has been carried out the next piston stroke magnitude from the series of piston stroke magnitudes is switched to, or when the last piston stroke magnitude had already been set, step iii) is proceeded with.
• the control device sets the metering device to the next piston stroke magnitude, until all piston stroke magnitudes from the series of piston stroke magnitudes have had their turn.
• step ii) each time that the weighing device has not weighed dough pieces for a predetermined time, the next piston stroke magnitude from the series of piston stroke magnitudes is switched to, or when the last piston stroke magnitude had already been set, step iii ⁇ is proceeded with.
• the metering machine can for instance temporarily stop metering after the pre set optimisation strokes for a piston stroke magnitude have been completed.
• the time in between the metering of dough and the dough reaching the weighing device is in this case called the cycle time.
• the cycle time the time in between the various dough weighings than the cycle time, preferably over 30 times the cycle time.
• the metering machine will have completed the optimisation strokes for a piston stroke.
• the standard deviation in weight of the dough portions is then calculated, after which the next piston stroke magnitude can be proceeded with.
• the metering device carries out the number of metering strokes at predetermined points in time, independent of the weighing device. In this way it is possible that between the metering device and the weighing device no communication is necessary during carrying out the metering strokes; not until the metering strokes for the entire range of piston stroke magnitudes have been completed and a piston stroke with the smallest standard deviation in weight of the dough portions is known, should it be known at the control device which pistons stroke that is in order to set it in the metering device.
• the assembly can be built up in a more modular manner and the machines are easier to replace.
• the optimal piston stroke magnitude optionally together with other machine parameters of the (dough) product, is stored to be re-used later.
• the optimal setting of the metering device may be different for each dough product.
• a previously stored optimal piston stroke magnitude and/or other machine parameters related to a dough product are retrieved and used by the control device for setting the piston stroke of the metering device. In that way optimal piston stroke magnitudes found earlier can be set without carrying out the optimisation again, also for identical metering machines in different bakeries.
• the present invention provides an assembly comprising a metering device, wherein the metering device comprises a hopper for the supply of dough to be metered, a piston that is movable in a first chamber, wherein the first chamber connects to the hopper, a blade member that is also movable in the first chamber and arranged between the piston and the hopper, at least one metering chamber, wherein the metering chamber is adapted for in at least one position connecting to the first chamber, and the metering chamber is movable with respect to the first chamber; a weighing device, placed downstream from the metering device, for determining the weight of dough portions coming out of the metering chamber; and a control device coupled to both the metering device and the weighing device, adapted for setting a piston stroke magnitude from a series of predetermined piston stroke magnitudes, wherein the control device is adapted for setting an optimal piston stroke magnitude of the metering device based on the standard deviation of measurements taken by the weighing device.
• the properties of said assembly render
• the assembly comprises a metering chamber that is closed off at one side by a metering piston driven by a first motor. In that way it is possible to have the setting of the metering volume run automatically.
• the assembly comprises a first sensor for determining at what volume the metering chamber has been bounded by the metering piston and for generating a first feedback signal on the basis thereof.
• a means preferably is a potentiometer, preferably coupled to the first motor.
• the first feedback signal can be used for both controlling the first motor accurately, so that the metering chamber is bounded at a certain volume, and for obtaining an accurate indication of the set metering volume when the metering volume is set manually.
• the assembly comprises a second motor, preferably a servomotor, to drive the piston.
• the assembly comprises a second sensor, able to provide a second feedback signal in which position the piston is and/or how much force the motor exerts on the piston.
• the second feedback signal can also be given by the servomotor.
• the assembly comprises a control device which is adapted for adjusting the ejection stroke of the piston 1 on the basis of the first and/or second feedback signal. In that way it can at least partially be prevented that the dough is pressurised too much.
• An embodiment of the present invention comprises said assembly wherein the control device is adapted for executing an instruction program, placed on a medium, for carrying out an above-mentioned method.
• the assembly comprises memory means for storing optimal piston stroke magnitudes and/or other machine parameters for the dough product. These data can be used afterwards by an embodiment wherein the assembly comprises an entering means for entering the recipe and/or machine parameters of the dough product and for selecting piston stroke magnitudes that have previously been stored with previously stored dough recipes. As a result it will no longer be necessary to carry out a piston stroke optimisation for dough types for which the optimal piston stroke has already been stored before.
• the entering means of the assembly comprises a touch screen.
• Said input means is easy to operate and easy to clean.
• the present invention provides a computer program which when loaded in a computer memory comprises program instructions for carrying out the above-mentioned method.
• Figure 1 a shows a schematic view in cross-section of a dough metering device
• Figure 1 b shows the same dough metering device wherein the piston has been moved to push dough from the suction chamber in the direction of the metering chamber;
• Figure 2 shows a dough metering device wherein the metering chamber deposits the metered dough portion onto a conveyor belt in order to be weighed by a weighing device;
• Figure 3 shows an example of an entering means, in this case a touch screen, of the assembly, wherein the entering means is adapted for entering and/or selecting parameters for the method for setting the optimal piston stroke magnitude;
• Figure 4 shows a flow chart of the method of the present invention wherein the number of optimisation strokes per piston stroke magnitude is set beforehand.
• FIG 1 a a dough metering device is shown wherein the dough mass is stored in a dough hopper 4 which can be closed off from a suction chamber 5 by a blade member 2.
• a slide 7 is shown here in a lowermost position as a result of which there is no passage between the metering chamber 6 and the suction chamber 5.
• the volume of the metering chamber is bounded by a metering piston 3.
• a first sensor ⁇ not shown) is able to give a first feedback signal indicating at which volume the metering chamber has been set.
• a piston 1 moves away from the slide as a result of which dough is sucked from the dough hopper into the suction chamber.
• FIG 1 b the blade member 2 has closed off the connection between the suction chamber 5 and the dough hopper 4.
• the slide 7 has been moved to an uppermost position as a result of which the metering chamber 6 and the suction chamber 5 connect to each other.
• a movement of the piston in the direction of the slide pushes, at least a part of, the dough from the suction chamber into the metering chamber.
• a second sensor (not shown) is able to give a second feedback signal indicating how much force is exerted by the piston, which is also an indication of the pressure to which the dough is exposed.
• Said second feedback signal can be used to provide feedback to the piston so that the ejection stroke of the piston can be adapted according to wish.
• the slide with full metering chamber has been moved to the lowermost position, where the metering pistons eject the metered portion of dough 23 onto a conveyor belt 22 which passes the dough to a weighing device 21.
• the weighing device comprises means, preferably a photocell, that are used to establish whether there is a dough portion on the weighing device in order to be weighed.
• a predetermined time period preferably 30 times the cycle time of a portion of dough, no dough products have been weighed by the weighing device, the next piston stroke magnitude is switched to until all piston stroke magnitudes have had their turn and the optimal piston stroke has been found.
• the metering device When the metering device for instance has carried out the metering stokes for a piston stroke magnitude then the metering device (temporarily) stops metering as a result of which after one cycle time at the most, no dough portions end up on the weighing device for a prolonged duration. If for instance there is no more dough in the hopper, the optimisation process according to this method will be completed, wherein it can be indicated that for certain piston stroke magnitudes no dough portions have been weighed.
• FIG 3 an exemplary input means of an embodiment of the assembly according to the present invention is shown.
• the input means in this case is a touch screen with which the number of strokes for optimisation can be set and with which the order can be given for retrieving and/or storing combinations of the piston stroke magnitude and the related other machine parameters for the dough product.
• FIG 4 an embodiment of the present method is shown in a flow chart. It is possible to let the execution of the method take place by three parts of an assembly for metering dough, wherein the assembly in this case comprises a metering device 400, a conveying device 500, and a weighing device 600. After starting 401 the metering device, the number of metering strokes per piston stroke magnitude is set 402. Said number of metering strokes can be set by a user or automatically.
• the piston stroke magnitude of the metering device is set to the largest piston stroke magnitude 403 for which the standard deviation of the resulting dough portions has to be determined.
• one piston stroke is carried out 404 of which the resulting dough portion(s) are discharged and ignored by the weighing device.
• the set number of metering strokes is subsequently carried out 405, after which it is verified whether the smallest piston stroke has already been set 406. If this is not the case, and there still are piston stroke magnitudes for which no optimisation strokes have been carried out then the next largest piston stroke is set and the metering of dough portions is temporarily stopped 407.
• the metering device is able to discharge the metered dough via the conveying device (500), which conveys the dough portion(s) to the weighing device (600).
• the weighing device After starting (601 ) the weighing device and starting a new series of dough portions for determining the standard deviation in weight, it is determined, preferably by means of a photocell, whether there is a dough portion on the weighing device (602). If this is the case the dough portion is weighed and discharged (603). When no dough portion has been found it is verified whether at least one cycle time, preferably 30 times the cycle time of a piece of dough from the metering device to the weighing device, has passed by since the last time dough was found on the weighing device (604). Such a time span that no dough Is found on the weighing device occurs for instance when the metering device has finished carrying out the entered number of metering strokes for a piston stroke magnitude.
• the standard deviation in weight of the series of dough portions is calculated and stored 605 and a signal is sent to the control device for starting 606 the metering device so that it starts metering again after which weighing a new series can be started with 404. In between two dough weighings such a signal is sent only once.
• the metering machine has 4 metering chambers and a capacity of 1800 strokes per hour, therefore per hour
• 7200 pieces of dough can be metered.
• the number of metering strokes per piston stroke magnitude in this example is set at 4. When starting the optimisation the first 4 products are ignored. The next 16 products ⁇ 4x4 ⁇ are weighed and the standard deviation is determined. The metering device is stopped, but the discharge conveyance continues for discharging the products between the metering device and the weighing device. When the metering device has not found products for
• the control device sets, starts and stops the metering device at predetermined points in time, without the control device first having received a signal from the weighing device that for a certain time no dough portion has been weighed anymore.
• the metering device is stopped and then 15 seconds have to be waited for so that the weighing device knows that the last dough portion for the piston stroke magnitude in question has been weighed.
• the metering device from the example is able to start with the next piston stroke magnitude, wherein the weighing device has sufficient information at its disposal to be able to calculate a correct standard deviation in weight of the dough portions.
• both the metering device and the weighing device have counters for the number of metered dough portions and the number of weighed dough portions, respectively.
• counters for the number of metered dough portions and the number of weighed dough portions, respectively.

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• Life Sciences & Earth Sciences (AREA)
• Engineering & Computer Science (AREA)
• Food Science & Technology (AREA)
• Manufacturing And Processing Devices For Dough (AREA)

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Cited By (3)

Citations (7)

• 2008
  • 2008-12-04 NL NL2002288A patent/NL2002288C2/nl not_active IP Right Cessation
• 2009
  • 2009-12-01 WO PCT/NL2009/050729 patent/WO2010064908A1/en active Application Filing

Patent Citations (7)

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