IMPROVED VOLUMETRIC BATCHER, PARTICULARLY FOR CHAMOMILE FLOWERS TO BE PACKED IN FILTER-BAGS

Abstract: An improved volumetric batcher is described, particularly suitable for a dosed feeding of a dishomogeneous and scarcely slidable as well as extremely fragile product, such as chamomile flowers, to be introduced in filter-bags. It comprises several batching units placed side by side, in order to allow the operation with high-speed packing machines, all of them fed by a single container in the bottom of which as many screw-feeders are provided as the batching units, to push the product in the corresponding vertical loading conduit. Said conduit, in which a pneumatic piston works to compress the product in the batching chamber below, is aligned with both a hole passing through a fixed plate which supports the actual batcher, and said batching chamber obtained inside a mobile second plate of the batcher, when this second plate is in the loading position, while in the opposed discharging position of said plate the batching chamber is aligned with both a second hole of the fixed supporting first plate, which hole serves for the passage of an ejecting piston, and a discharging hole of a fixed underlying third plate of the batcher.

Description: IMPROVED VOLUMETRIC BATCHER, PARTICULARLY FOR CHA¬ MOMILE FLOWERS TO BE PACKED IN FILTER-BAGS. The present invention relates to an improved volumetric batcher, particularly for chamomile flo¬ wers. It is known to pack products for infusions, such as tea, chamomile and the like, inside filter- bags. Recently it increased and gained favour among the consumers a product called "filtro-fiore" in Italian (flower-filter in English), consisting of almost integral chamomile flowers which have to result, ' upon being packed, as much as possible in¬ tact to merit such a name. This product is per se scarcely slidable, ex¬ tremely fragile and dishomogeneous, as the various parts which compose a chamomile flower, and have to be comprised in the product, have physical charac¬ teristics, particle size and specific weight consi- derably different from each other. Up to now a batcher designed by the same ap¬ plicant has been adopted for the dosed filling of filter-bags in a packing machine of known type, which batcher proved to be relatively sufficient as far as both the quality of the product and the pro- tection of the physical aspect thereof are concer¬ ned. The batcher is of the volumetric type, as it is not conceivable to employ batchers on a ponderal basis, each dosing being about 2g in weight and the relative weighing having to occur at a rhythm of about 100 times per minute, with minimum deviations per cent and therefore negligible ones in absolute value. In the known batchers it was possible to over- come the problem of a reliable batcher filling, thus avoiding the so called "bridges" of material, due to both the dishomogeneity of the product and the dimensions thereof, and taken into account that a bud of chamomile with its stalk can have an ove- rail length of 3 ÷ 3.5 cm, thus involving, as a re¬ sult of its arrangement, problems in filling the batcher, up to block the passage of more product. The problem was solved by adopting a mobile bat¬ ching chamber inside which the filling takes place by a free fall of the product and a successive com¬ pression thereof by means of a pad actuated by a pneumatic cylinder. Such a batching chamber is formed in a mobile plate and is closed at its bot¬ tom by a small door which is adjustable in height to change the dose volume and can be opened each time for discharging the product. The batcher con¬ sists of both said mobile plate and a fixed suppor¬ ting one which has a through hole with the same si¬ ze of the batching chamber. When the latter is a- ligned with said through hole of the fixed plate, which hole is arranged coaxially with the vertical of a loading conduit through which said compressing pad slides, there occurs the filling of the bat¬ ching chamber which, at the following stroke of the mobile plate, causes the clean cut of a core of product, due to the sliding of the upper edges of the batching chamber against the lower surface of the fixed plate above, while the upper surface of the mobile plate prevents the product from falling from both the loading conduit and the through hole of the fixed plate. The small door opens near the end of a stroke of the mobile plate, with conse¬ quent falling down of dosed product in a filter-bag below, which is submitted by the packing machine. The vertical loading conduit was communicating with a hopper continuously fed by a reservoir through a screw-feeder which, by drawing therefrom, can raise the product up to the upper edge of said hopper, while anyhow needing additional means such as spi- rals at its sides, to overcome the difficulties of - . - drawing due to the scarce smoothness of the pro¬ duct, but with the consequence of some damages to the integrity of the product itself. In spite of the merits of the above briefly described device, the most considerable limit the¬ reof remains a limited productivity, as it has a filling rate of about 100 filter-bags per minute, and there having been moreover found that, for ra¬ tes higher than 110 cycles per minute, the gravity fall just after the opening of the small door with a slight advance with respect to the forming of a filter-bag, involves different fall times, mainly due to the dishomogeneity of each component. Thus it is not possible to increase the working rate of the batcher to have it coincident with the working rate of faster packing machines which teorically could ensure a higher productivity. Also the experimented hypothesis of employing a carousel of small containers placed between the batchers and a single packing station resulted to be not practicable as, by using N intermediate con¬ tainers, the batchers rate would positively be 1/N of the machine rate, but the transfer of the dose to the carousel and therefrom to a filling area, would have anyhow to take place in a very short ti- me, less than l/( N x 100 ). The limit seems to be mainly due to the free fall of the product. Thus an improved batching device has been con¬ ceived and forms the object of the present inven- tion, which does not show the above mentioned draw¬ backs, as it has a filling rate which is, on the whole, higher and adequate to the working rate of already existing packing machines which are suita¬ ble to work at the same time, with high productivi- ty, at many stations for filter-bags filling, wit¬ hout proportionally increasing the batcher working rate. This is obtained by a device comprising a re¬ servoir upstream of a dispensing unit with a sub- stantially vertical loading conduit inside which a compressing pad shifts lengthwise in two opposite directions, coaxially with a hole of a stationary supporting first plate below which, while remaining always in contact therewith, a plate shifts hori- zontally, a batching chamber being formed therein, and means being provided to keep closed the bottom of the latter up to a discharging position of said plate, and comprising as well several dispensing units each of them fed by said reservoir through a screw-feeder arranged substantially horizontal at the bottom of said reservoir with its terminal part housed inside a conveying conduit which branches off, in parallel to other conduits, from said re¬ servoir, each of them being communicating with the respective conduit, wherein moreover said means for closing the bottom of the batching chamber consists of a second stationary plate arranged below said mobile plate and in direct contact therewith, which has a through hole in its discharging area, coaxial to and having the same transversal dimensions of a second hole in said first plate. It should be noted that the size of the reser¬ voir, a single one for all the units, allows to em¬ ploy, for the feeding thereof, an element like a conveyor-belt without needing a lifting screw- feeder, thus eliminating the above mentioned draw¬ backs which derive from employing spirals which en¬ sure the drawing of the screw-feeder itself. In fact the screw-feeders employed in this case for pushing the product towards each loading conduit, result to be completely immersed in the mass of product, as they are arranged at the container bot¬ tom, whereby the above cited problems of drawing do not occur, also because the screw-feeders operate horizontally and have not to convey the product up- wards. According to a particular aspect of the pre¬ sent invention, each screw-feeder is actuated indi- pendently by a motor combined thereto, through a varying torque such to fill in a controlled way the loading conduit, as a function of the consumption and depending on the desired degree of compression. The latter feature can be also controlled by adju¬ sting the force exerted by the compressing pad inside the discharging conduit. In such a way, by varying the product density, more or less compres¬ sed, the weight of each dose can be changed in a completely indipendent way. Another advantage obtainable with respect to a single batcher according to the prior art, is the absence of mechanic elements at the discharge of the product, like the small door which had to open in advance with respect to reaching the filling station, with consequent possibility of approaching the final container of the dosed quantity. These and other aims, advantages and characte¬ ristics of the batching device according to the present invention will be more clear from the fol¬ lowing detailed description of a preferred embodi- ment thereof, given as a non-limiting example with reference to the sole drawing attached, which shows a sectional diagrammatic view of a single batching unit. With reference to the drawing, one of the bat- ching units forming the device according to the present invention is diagrammatically represented in section, connected, as well as the other units not visible in the drawing, to the common container 1 of the product through a conveying conduit 12. From the container 1 itself other conveyors 12 branch off, in particular three ones else in the hypothesis of a battery of four batching units, in parallel to each other. The container 1 receives the material, in particular formed of whole chamo- mile flowers, as above specified, but possibly also of a different type of product having similar cha¬ racteristics, by means of a conveyor-belt A. The feeding through the belt A is such that in the con¬ tainer 1 a level 2 is kept as much as possible con- stant by means of a sensor suitable to control the number of revolutions of the actuating motor of the belt itself. At the bottom of container 1, in corresponden¬ ce with each conveying conduit 12, a screw-feeder 8 is provided, the total number of which is equal to that of the batching units, possibly parallel to each other. As in the first part of the screw-fee¬ der this one directly contacts the product dischar¬ ged by the conveyor-belt, at the bottom of contai- ner 1, every possibility of forming "bridges" is prevented, and then empty pockets, inside the con¬ tainer. Each screw-feeder, actuated indipendently by a motor 9, pushes the product through the con¬ duit 12 in the vertical loading conduit 11 associa- ted therewith. The pressure exerted on the pro¬ duct, and then the compression thereof inside the passage 12, depends on the adjustable torque or twisting moment exerted by the motor 9, while the degree of compression inside the conduit 11 is also a function of the force by which a pad 4 is pushed downwards, actuated by a hydraulic cylinder or a pneumatic one. The actual batching unit consists of three plates overlapped to each other, among which both the upper 5 and lower 7 are stationary, and the middle one 6 is mobile. The plate 5 works as an element for both supporting and cutting a core of product, while plate 6 is the mobile element of the batcher, and the batching chamber 16 is obtained therein. In other words, the thickness of plate 6 determines the height of the cylinder or core of product obtainable at each dosing, whose volume is therefore constant, not variable as it was instead with the above described known apparatus, but in a not easy way due to both the need of shifting the fixing point of the small door inside the dispen¬ sing chamber and the drawbacks caused by the neces¬ sary advanced opening of said small door before reaching the filling station. In the following it will be described how to obtain the control of the quantity of product at each batch, while keeping constant the batching chamber volume. The plate 5 has a through hole 14 coaxial to and having the same cross-section of the loading conduit 11, as well as a second through hole 15 in correspondence with the area for ejecting the pro¬ duct. A pad 10 vertically actuated along two oppo¬ site directions (double arrow F") by a means (not represented) such as a pneumatic cylinder or a ki- nematic mechanism, preferably syncronous with the packing machine, can pass through the whole hole 15 until reaching, in correspondence with the lower stroke-end, a point below plate 5. The plate 6 is transversally mobile in two opposite directions, as shown by the arrow F' , between the two fixed plates 5 and 7, from a feeding position, as represented in the figure, in which the batching chamber 16 is a- ligned with the hole 14 and the loading conduit 11, to an opposed discharging position in which said chamber 16 is aligned with the hole 15. The lower plate 7 has moreover a hole 17 coaxial to and ha¬ ving the same cross-section of the hole 15, such as to result coaxial also with the dispensing chamber 16, as well having, when this is in the discharging position, the same cross-section thereof. As already mentioned above, each screw-feeder 8 is preferably actuated by a single motor 9 con¬ trolled indipendently from the others such to vary its output torque and therefore the applied twi- sting moment M, through the transmission parts 9a, on the axis 8a of the screw-feeder 8, what causes a variation of the product density, especially inside the conveying conduit 12. This is a first regula¬ tion of the density to which the one joins due to pad 4, which is mobile along the two directions shown by the double arrow F inside the loading con¬ duit 11. By suitably operating on the actuating part 3 thereof, the compression can be increased or decreased, and therefore the density, inside the loading conduit, whereby inside the dispensing chamber more product or less can be contained at will, depending on the need. It should be noted that, differently from the previously known dispen¬ ser, in which only the piston compressed the pro- duct, otherwise soft, to fill the batching chamber, now a return of the pad to the initial position thereof before that the forward movement of plate 6 causes a core of product to be cut, would not undo the compressing effect of the pressure exerted u- pstream of the screw-feeder. The working of the device according to the in¬ vention, as it clearly results from the above de¬ scription, is the following. The product, in par¬ ticular chamomile in whole flowers, coming from previous operations, is fed by any known way, but anyhow freely and without mechanic mistreatments, on a lifter-conveyor belt A from which it falls down by gravity inside a reservoir 1 common to all the batching units and therefore having a suffi- ciently wide cross-section, as above said. The flow of product supplied by the belt A is control¬ led so as to keep a certain level 2 inside reser¬ voir 1. The various screw-feeders are actuated to push the product through the conveying passages 12 and then in the loading conduits 11 from which, by the pressure exerted by the corresponding pads 4, through the holes 14 the chambers 16 of each di¬ spensing unit are filled with a suitable density to have the desired weight, while taking into account the fixed predetermined volume of the chamber it¬ self. Once the latter is filled, plate 6 approa¬ ches the discharging area (right direction of the arrow F') and the pad 4 raises, the chamber 16 rea¬ ches a position coaxial to both holes 15 and 17, and all the contents thereof is ejected under the plate 7 through a downwards thrust exerted by the piston 10. This action takes place contemporaneou¬ sly for all the batching units, so as to work in synchronism with the packing machine which, in the meanwhile, has submitted -the filter-bags, ready to receive the product, under the various holes 17 of all the units. Finally, whatever number of bat¬ ching units can be provided, depending on the em¬ ployed packing machine, and the screw-feeders 8, and then the passages 12, could be non-parallel to each other but arranged, for instance, in a dial surrounding the reservoir 1.

Claims: CLAIMS 1. An improved volumetric batcher, in parti¬ cular for chamomile flowers to be packed in filter- bags, comprising a reservoir (1) upstream of a di¬ spensing unit with a substantially vertical loading conduit (11) inside which a compressing pad (4) shifts lengthwise in two opposite directions, coa¬ xially with a hole (14) of a stationary supporting first plate (5) below which, while remaining always in contact therewith, a plate (6) shifts horizon¬ tally, a batching chamber (16) being formed the¬ rein, and means being provided to keep closed the bottom of the latter up to a discharging position of said plate (6), characterized in that it compri- ses several dispensing units each of them fed by said reservoir (1) through a screw-feeder (8) ar¬ ranged substantially horizontal at the bottom of said reservoir (1) with its terminal part housed inside a conveying conduit (12) which branches off, in parallel to other conduits (12), from said re¬ servoir (1), each of them being communicating with the respective conduit (11), wherein moreover said means for closing the bottom of the batching cham¬ ber (16) consists of a second stationary plate (7) arranged below said mobile plate (6) and in direct contact therewith, which has a through hole (17) in its discharging area, coaxial to and having the sa¬ me transversal dimensions of a second hole (15) in said first plate (5). 2. A batcher according to claim 1, characte¬ rized in that each screw-feeder (8) is actuated by an associate motor (9) which is controlled indipen- dently from the others to vary the torque on the axis of the screw-feeder itself. 3. A batcher according to claims 1 and 2, characterized in that also the thrust force exerted by said pad (4) actuated by a bidirectional motor means (3) is controllable , whereby the quantity of product inside said batching chamber (16), with a constant volume, is adjustable by acting on said motors (3,9) . 4. A batcher according to one or more of the preceding claims, characterized in that along the vertical of said through holes (15,17) of the fixed plates (5,7) a second pad (10) is axially shiftable in two opposite directions with a bidirectional ac¬ tuation, for ejecting the product contained in said batching chamber (16) when this is aligned with said holes (15,17) in said discharging position of the plate (6) . 5. A batcher according to claim 4, characteri¬ zed in that the actuation of said ejecting pads (10) is contemporaneous for all the batching units of the same batcher, and synchronous with the pac- 5 king machine. 6. A batcher according to claim 1, characte¬ rized in that a conveyor-belt (A) is provided for continuously feeding said reservoir (1). 7. A batcher according to claim 6, characte- 10 rized in that the number of revolutions of the ac¬ tuating motor of said conveyor-belt (A) is control¬ led by a sensor for maintaining a predetermined le¬ vel (2) inside said reservoir (1). 8. A batcher according to the preceding claims, characterized in that said batching chamber (16) has a cross-section equal to that of the other holes (14,15,17). 9. A batcher according to one or more of the preceding claims, characterized in that the stroke 0 of said mobile plate (6) from a loading position to the discharging one causes the cutting of a small cylinder or core of product, having a height equal to that of the batching chamber(16), from a cylin¬ der of compressed product extending up to the loa- ^ ding conduit (11) .

Inventors: BONOMELLI FEDERICO, BONOMELLI, FEDERICO
Applicants: BONOMELLI SPA, BONOMELLI S.P.A.
Application year: 1992
Main classification: B65B1
IPC codes: B65B1