FILLING MACHINE FOR FOOD PRODUCTS IN CANS, PARTICULARLY OF THE TYPE WITH PRODUCT DENSITY CONTROL

Abstract

A filling machine for food products in cans, particularly of the type with product density control, comprising a supporting frame which forms a chamber and a feeding tunnel which is adapted to convey a food product into the chamber that is provided with a plunger which can move along the chamber, along a predefined compression direction; the chamber being provided with an expulsion piston configured to move transversely with respect to the compression direction for the expulsion of at least one preset shape in the direction of a station for canning the food product; a motor being provided which is associated with the plunger for a movement along the compression direction; and elements for measuring the density of the food product compressed in the chamber in order to control the driving torque of the motor as a function of the achievement of a predetermined density value.

Claims

1-12. (canceled)

13. A filling machine for food products in cans, particularly of the type with product density control, comprising a supporting frame which forms a chamber and a feeding tunnel which is adapted to convey a food product into said chamber; said chamber being provided with a plunger which can move along said chamber, along a predefined compression direction, between a bottom dead center position (PMI), in which said chamber is free from said plunger in order to feed said food product into said chamber, and a top dead center position (PMS), in which said plunger occupies at least partially said chamber for a compression of said food product into at least one preset shape; said chamber being provided with at least one expulsion piston which is configured to move transversely with respect to said compression direction for an expulsion of said at least one preset shape in a direction of a station for canning said food product; motor means being further provided which are associated with said plunger for a movement thereof along said compression direction; and further comprising means for measuring a density of said food product compressed in said chamber in order to control a driving torque of said motor means as a function of an achievement of a predetermined density value.

14. The filling machine according to claim 13, wherein said means for measuring the density of said food product compressed in said chamber comprise means for measuring a driving torque of said motor means.

15. The filling machine according to claim 13, wherein said motor means comprise a mechatronic system constituted by a control unit, a rotary servo motor of the brushless type provided with an encoder, and a speed reduction unit.

16. The filling machine according to claim 13, wherein said motor means are associated with said plunger by virtue of a first rod-and-crank mechanism.

17. The filling machine according to claim 13, wherein said feeding tunnel comprises a plurality of conveyor belts which are oriented parallel to each other so as to form a passage channel interposed between said conveyor belts; said conveyor belts comprising an upper conveyor belt, a lower conveyor belt, and two lateral conveyor belts.

18. The filling machine according to claim 13, wherein said feeding tunnel comprises a plurality of skimming elements which are arranged at an inlet of said chamber for an optimum conveyance of said food product into said chamber.

19. The filling machine according to claim 13, wherein said feeding tunnel has a longitudinal extension that is substantially perpendicular to said compression direction.

20. The filling machine according to claim 16, wherein said chamber is delimited, on an opposite side with respect to said plunger proximate to said top dead center, by an abutment element which is contoured, on a side directed toward an inside of said chamber, with a geometric profile which reproduces in negative form a portion of said at least one preset shape.

21. The filling machine according to claim 20, wherein said abutment element is shaped to form at least two predefined shapes; said at least one expulsion piston comprising at least two expulsion pistons which correspond to said geometric profile of said abutment element.

22. The filling machine according to claim 20, further comprising adjustment means for adjusting a position of said abutment element along said compression direction.

23. The filling machine according to claim 21, wherein said adjustment means comprise a servomotor which is associated with said abutment element by means of a second rod-and-crank mechanism in a cascade arrangement with respect to a guiding and adjustment device.

24. A method for the filling of food products in metallic boxes, cans, comprising the steps of: feeding a food product to a chamber provided with a plunger which is configured to move along said chamber, along a predefined compression direction, between a bottom dead center position (PMI), in which said chamber is free from said plunger in order to feed said food product into said chamber, and a top dead center position (PMS), in which said plunger occupies at least partially said chamber for a compression of said food product into at least one preset shape; setting up a predetermined density value of said food product; compressing said food product by means of said plunger; measuring a density of said food product compressed by said plunger in said chamber; actively controlling, during the compression of each single compression cycle, a driving torque of the motor means adapted to move said plunger, said driving torque being controlled by detecting a density of the food product compressed and adjusting said driving torque in order to achieve said predetermined density value of said food product; upon achieving said predetermined density value of said food product stopping a stroke of said piston in a position that corresponds to said predetermined density value, avoiding compressing further said food product.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Further characteristics and advantages will become better apparent from the description of a preferred but not exclusive embodiment of a filling machine for food products in cans, particularly of the type with product density control, illustrated by way of non-limiting example with the aid of the accompanying drawings, wherein:

[0021] FIG. 1 is an exploded perspective view of the internal components of a filling machine according to the present invention;

[0022] FIG. 2 is a chart which plots the position and torque curves of the plunger of the filling machine shown in FIG. 1, without the product in the chamber;

[0023] FIG. 3 is a chart which plots the position and torque curves of the plunger of the filling machine shown in FIG. 1, with the product in the chamber.

DETAILED DESCRIPTION

[0024] With particular reference to FIG. 1, the filling machine for food products in cans, particularly of the type with product density control, generally designated by the reference numeral 1, comprises a supporting frame, not shown for the sake of graphic simplicity, which forms a chamber 2 and a feeding tunnel 3 which is adapted to convey a food product or the like 4 into the chamber 2.

[0025] In greater detail, the supporting frame comprises two lateral guides 5 and 6 that delimit laterally the chamber 2 inside which a plunger 7 slides, along a predefined compression direction 8, between a bottom dead center position PMI, in which the chamber 2 is free from the plunger 7 in order to feed the food product or the like 4 into the chamber 2, and a top dead center position PMS, in which the plunger 7 occupies at least partially the chamber 2 for the compression of the food product or the like 4 into at least one preset shape, called in the jargon tablet.

[0026] Conveniently, the plunger 7 is associated with motor means 9 for its movement along the compression direction 8.

[0027] In greater detail, said motor means 9 comprise a mechatronic system constituted by a control unit (MAC or PLC or the like), on which dedicated software is installed which contains an algorithm developed for this purpose, which manages a rotary servo motor of the brushless type 10 provided with an encoder, and a high-performance speed reduction unit 11 such as, for example, a constant-speed globoid cam positioning device, an epicyclic reduction unit or the like, and are associated with the plunger 7 by means of a first rod-and-crank mechanism 12.

[0028] According to the invention, the filling machine 1 comprises means for measuring the density of the food product or the like 4 compressed in the chamber 2 in order to control the driving torque of the motor means 9 which are managed by an algorithm (software) capable of detecting actively, during the compression step of each individual cycle, the density of the product and of adjusting accordingly the thrust values in order to achieve the predetermined density value.

[0029] More specifically, the density measuring means comprise an algorithm which, once the density of the product has been set, intervenes at each cycle by checking and adjusting the thrust of the motor means 9 so that when the desired density has been reached the thrust stops, locking and maintaining the plunger in position.

[0030] Such algorithm, in order to determine the correct thrust value of the motor means for reaching the desired density, monitors various parameters including, by way of non-limiting example, the force, the position, the time, the frictions, the temperature and the inertias of the operating cycle.

[0031] In this manner, the drawbacks of known machines are eliminated, since the invention allows to have the active control of the thrust of the plunger at each cycle, ensuring the achievement of the desired density and, consequently, a qualitatively superior product.

[0032] Advantageously, the chamber 2 is delimited, on the opposite side with respect to the plunger 7 proximate to the top dead center, by an abutment element 13 which is contoured, on the side directed toward the inside of the chamber 2, with a geometric profile 14 which reproduces in negative form a portion of said at least one preset shape or tablet.

[0033] Furthermore, the chamber 2 is provided with at least one expulsion piston 15 which can move transversely with respect to the compression direction 8 for the expulsion of said at least one preset shape or tablet in the direction of a station for canning the food product or the like 4.

[0034] More specifically, in the proposed embodiment, the abutment element 13 is shaped in order to define at least two preset shapes or tablets, and there are at least two expulsion pistons 15 which correspond to said geometric profile 14 of the abutment element 13.

[0035] In a variation of the proposed embodiment that is not shown, the abutment element 13 can be shaped to form multiple preset shapes or tablets, for example three or four. Accordingly, a matching number of expulsion pistons, which are mutually independent or integral with each other and correspond to the geometric profile of the abutment element 13, is provided.

[0036] Advantageously, means 16 for adjusting the position of the abutment element 13 along the compression direction 8 are provided which comprise a servomotor 17 which is associated with the abutment element 13 by means of a second rod-and-crank mechanism 18 in a cascade arrangement with respect to a guiding and adjustment device 19.

[0037] In the proposed embodiment, the feeding tunnel 3 comprises a plurality of conveyor belts which are oriented parallel to each other so as to form a passage channel interposed between them.

[0038] In greater detail, the conveyor belts comprise an upper conveyor belt 20, a lower conveyor belt 21, and two lateral conveyor belts 22, of which only one is shown for the sake of simplicity in illustration.

[0039] Conveniently, the feeding tunnel 3, which has a longitudinal extension that is substantially perpendicular to the compression direction 8, comprises a plurality of skimming elements 23, 24 and 25, one for each conveyor belt, arranged at the inlet of the chamber 2 for the optimum conveyance of the food product or the like 4 into the chamber 2.

[0040] In the proposed embodiment, said inlet is formed by a front plate 26 arranged so as to close the chamber 2.

[0041] The general operation of the filling machine 1 is clear and evident from what has been described so far.

[0042] With particular reference to FIGS. 2 and 3, the torque behavior of the motor means 9 as a function of the position of the plunger 7, without and with the food product or the like 4 placed in the chamber 2 respectively, is described hereinafter.

[0043] More specifically, the algorithm allows control of the movement of the plunger 7 along the chamber 2, a movement which can be divided into three steps.

[0044] In the first step, the algorithm gives the command to the motor means to raise the plunger 7 from the bottom dead center PMI to the vicinity of the top dead center PMS.

[0045] In the second step, the algorithm commands the motor means to reverse the motion of the plunger 7 proximate to or at the top dead center PMS, and the third step represents the descent of the plunger 7 from the top dead center PMS until it returns to the initial position, i.e., at the bottom dead center PMI.

[0046] Subsequently, there is a fourth step which corresponds to a waiting step, in which the food product or the like 4 is loaded into the chamber 2 in order to then start again with the first step.

[0047] With particular reference to FIG. 2, without the food product 4 or the like placed in the chamber 2, in the first step the algorithm commands the motor means 9 to impart a positive driving torque, correspondingly to the step for accelerating the plunger 7; then, by way of indication halfway through the rising step, the algorithm commands a reversal of the driving torque, so as to correspond to the deceleration step of the plunger 7, until the top dead center PMS is reached, which, in the absence of the product, by detecting the failure to reach the pre-configured torque limit value, corresponds to a predetermined plunger stroke limit value, at which the driving torque becomes zero, partially completing the second step.

[0048] Again in the second step, the algorithm commands the motor means 9 to impart a negative driving torque, so as to correspond to the acceleration step of the plunger 7 in the step for recalling the plunger 7; subsequently, in the third step, which corresponds by way of indication to halfway along the path of the descending step, the algorithm commands an inversion of driving torque, so as to correspond to the deceleration step of the plunger 7, until the bottom dead center PMI is reached, which even in the absence of the product corresponds to a predetermined limit value of the stroke of the plunger, at which the driving torque becomes zero again.

[0049] With particular reference to FIG. 3, with the food product or the like 4 placed in the chamber 2, in the first step the algorithm commands the motor means 9 to impart a positive driving torque, in a manner that corresponds to the acceleration step of the plunger 7; subsequently, by way of indication halfway along the path of the rising step, a reversal of driving torque occurs which is managed by the algorithm in a manner that corresponds to the deceleration step of the plunger 7.

[0050] The plunger 7 rises along the compression direction without reaching the top dead center PMS due to the presence of the food product or the like 4 which inevitably creates thickness.

[0051] The algorithm, for each individual cycle, detects the achievement of the predetermined density of the product by measuring the torque of the motor means 9 and commands the motor means 9 to stop, locking and maintaining the plunger in position.

[0052] Upon achieving at each individual cycle, the predetermined density of the food product or the like 4, the algorithm commands the motors to stabilize the plunger in position.

[0053] In this manner, the plunger 7, for each individual cycle, is brought and kept in different positions without over-compressions by virtue of the algorithm that manages the driving torque of the motor means 9, which is controlled so as not to impart additional thrust force to the product.

[0054] At this point, the expulsion pistons 15 intervene and remove the tablets of food product or the like 4 from the chamber 2.

[0055] In this case, the second step is substantially constituted by the parking of the plunger 7 at an intermediate height between the bottom dead center PMI and the top dead center PMS proximate to the top dead center and at the preset density value.

[0056] In greater detail, during the first step, while the motor means 9, for each individual cycle, perform the positioning of the plunger 7 at the height that allows to achieve the predetermined density, if the algorithm detects that a preset determined torque value has been exceeded, due to the compression of the food product or the like 4, positioning is stopped in order to then move on to the second step while waiting for the third step.

[0057] Subsequently, the motor means 9 impart a negative driving torque, in a manner that corresponds to the acceleration step of the plunger 7 in the step for recalling the plunger 7 and, in the third step that corresponds by way of indication to halfway along the descending step, an inversion of driving torque occurs, in a manner that corresponds to the deceleration step of the plunger 7, until the bottom dead center PMI is reached at which the driving torque becomes zero again.

[0058] In practice it has been found that the filling machine for food products in cans, particularly of the type with product density control, according to the present invention, achieves the intended aim and objects, since it allows to: [0059] determine precisely at each individual cycle the density of the product with each consequent effect; [0060] reduce the squeezing time of the food product or the like to the minimum necessary to achieve the desired density, regardless of the speed of the filling machine; [0061] make the machine work at the maximum allowed speed without affecting product quality and, consequently, make production processes more efficient; [0062] increase the number of the cycles of compression of the food product or the like without damaging it, ensuring its quality; [0063] avoid thrust variations with respect to traditional systems (such as spring systems, pneumatic cylinder systems, or actuator systems), which would lead to pressure increments as the plunger position varies and therefore do not allow to obtain tablets with constant density; [0064] eliminate weight fluctuations of the tablets even just as the speed of the filling machine varies, compensating for the incidence of the forces generated by the inertias of the mechanism; [0065] control for each cycle the exact position of the plunger, so as to ensure good operation even in the event of pasting; [0066] control for each cycle the exact position of the plunger, eliminating external sensors, by virtue of a system directly integrated in the motor means; [0067] determine for each cycle the exact quantity of food product or the like inside the chamber; [0068] interact in real time and for each cycle, by means of a signal, with: the motorized chamber volume control system, the feeding tunnel, as well as the inlet section of the feeding port; [0069] compensate for any weight variations for each cycle by means of an external signal, such as for example a remote weighing device, arranged in a position that lies after the tablet generation step, which interacts with the system, varying automatically the working parameters of said system; [0070] simplify the mechanical complexity by using a mechatronic system.

[0071] The filling machine thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the accompanying claims.

[0072] All the details may furthermore be replaced with other technically equivalent elements.

[0073] In practice, the materials used, so long as they are compatible with the specific use, as well as the contingent shapes and dimensions, may be any according to the requirements and the state of the art.

[0074] The disclosures in Italian Invention Patent Application No. 102021000021224, from which this application claims priority, are incorporated by reference.