FR2860068A1 - Food product e.g. winter cauliflower, quantity determining process, involves determining thickness profile of transported food product at constant interval according to forward movement of conveyor - Google Patents

Abstract

The process involves measuring forward movement of a conveyor (12). A thickness profile of transported food products is determined at constant interval according to the forward movement of the conveyor. An estimation of a quantity of the transported food product is made based on the thickness profile and information relative to nature of the transported food products. An independent claim is also included for an equipment for processing food products.

Description

The present invention relates to a method and a determination system

  a quantity of food transported by a conveyor.

  The invention also relates to a food processing plant equipped for the determination of a quantity of food products transported and in particular a freezing installation.

  The known deep-freezing installations comprise, for example, a cryogenic freezing chamber or tunnel traversed by a conveyor on which foodstuffs to be frozen are deposited, the conveyor circulating continuously or sequentially through the freezing chamber.

  The operation of such a deep-freezing installation is a function of the quantity of food products to be treated, which directly influences the volume of cryogenic fluid required.

  Conventionally, the handling of food products before freezing is difficult, so that the amount of trans-food products is evaluated by an operator.

  Such an evaluation is inherently prone to approximations and errors resulting in the use of an inappropriate quantity of cryogenic fluid.

  In the case of food transport installations, however, there are means for determining thickness profiles of transported food products.

  In particular, the equipment of the company INTEGRATED VISION PRODUCTS, such as the device known as IVP Ruler, include a projector with a laser beam projecting perpendicular to the direction of advancement of products, a laser beam across the width of the conveyor .

  A specialized camera is focused on the region of encounter of this beam with the conveyor and is adapted to perform an image processing in order to deliver images of the deformations of this laser beam due to the passage of food products, these images forming profiles of thickness of products transported.

  Such means for determining the profiles of food products are used at the end of a treatment, in order to carry out a quality control or a volume measurement used for the control of equipment arranged downstream of the treatment, such as as for example cutting equipment.

  In these installations, the thickness profiles of food products are determined at regular time intervals, so that the means used are unsuitable for use in processing facilities comprising sequential or variable speed conveyors.

  It therefore appears that there is no method and facility for determining a quantity of transported food products capable of delivering an automatic and accurate evaluation, particularly in the case of a variable speed conveyor.

  The object of the present invention is to solve this problem by challenging a method and a system for determining a quantity of transported food products, automatic and of high accuracy.

  To this end, the subject of the invention is a method for determining a quantity of food products transported by a conveyor, characterized in that it comprises: a step of measuring the progress of said conveyor; a step of determining thickness profiles of transported food products, determined at a constant pitch, as a function of the progress of said conveyor; and a step of determining an estimate of the quantity of food products transported from said constant pitch thickness profiles and information relating to the nature of said food products. The method of the invention thus makes it possible to make an accurate and automatic determination of the quantity of food transported irrespective of the speed of travel or the mode of operation of the conveyor.

  According to other features of the invention: said step of determining constant pitch thickness profiles comprises for each profile: a substep of enumeration of forward measurements of said conveyor; and a substep of controlling the determination of a pro-wire thickness of transported food products, in order to control, when a predetermined number of steps of advancement of said conveyor is reached, the determination of a profile. of thickness at variable time intervals corresponding to a constant pitch of advancement of said conveyor; said step of determining an estimate of a quantity of transported food products, comprises: a substep of determining the area of each profile of determined thickness in a plane substantially orthogonal to the plane formed by said conveyor ; a substep of determining a volume of food products transported from the determination of an elementary volume for each determined thickness profile; and a sub-step of determining a mass estimate of food products transported as a function of said previously determined volume and the density of the transported food products; said step of determining an estimate of quantity of transported food products, further comprises a substep of correcting the mass estimate of transported food products as a function of a corrective coefficient representative of their density; said substep of determining an elementary volume for each determined thickness profile comprises multiplying the surface of a thickness profile by the length of said constant pitch; said substep of determining an elementary volume for each determined thickness profile comprises an integral calculation between two successive profiles over the length of said constant pitch.

  The invention also relates to an installation for determining a quantity of food products transported by a conveyor, comprising means for determining thickness profiles of food products transported on said conveyor, characterized in that it also comprises means for measuring the progress of said conveyor, means for controlling said thickness profile determining means in order to control the determination of thickness profiles of food products transported by the conveyor, determined at a constant pitch according to the measurements advancement of said conveyor, and means for determining an evaluation of quantity of food products transported from said thickness profiles and information relating to the nature of said food products.

  According to other characteristics of the installation of the invention: said means for determining thickness profiles of transported food products comprise a laser beam projector, adapted to project a laser beam perpendicular to the direction of advancement of said conveyor and over its entire width, and a camera arranged in a pre-determined manner with respect to said projector and focused on the region of intersection between said laser beam and said conveyor, said camera being adapted to deliver images of the deformations of said beam laser projected onto said conveyor due to transported food products, these images containing said thickness profiles of transported food products; - It is adapted to implement the method as described above.

  The subject of the invention is also a facility for treating food articles, comprising a treatment chamber controlled by control means, characterized in that it comprises an installation for determining a quantity of food products transported by a conveyor. as described above, said conveyor being adapted to transport said food items from an inlet to an outlet of said treatment enclosure and in that said means for determining the thickness profiles of transported food products are arranged upstream of said inlet with respect to the direction of advancement of said conveyor in order to deliver an evaluation of the quantity of food products transported at the inlet of said enclosure and in that said control means are adapted to control the operation of said enclosure as a function of this evaluation quantity of food products transported.

  The invention will be better understood on reading the description which follows, given solely by way of example and with reference to the appended drawings, in which: FIG. 1 represents a block diagram illustrating a freezing installation equipped according to the invention; Fig.2 is a flowchart of the method of the invention; and - Figs.3, 4A and 4B are diagrams illustrating different steps of the method of Figure 2.

  In Figure 1, there is shown a food processing plant, equipped according to the invention.

  This installation comprises a freezing chamber 2 of conventional type for freezing PA food products by bringing it into contact with a cryogenic fluid 4 conveyed by a feed line 6 from any source.

  Typically, the cryogenic fluid 4 used can be for example dry ice or liquid nitrogen and is injected in one or more places of the enclosure 2.

  In the example described, the enclosure 2 has the shape of a rectangular parallelepiped, extending from an inlet 8 to an outlet 10.

  The chamber 2 passes through the inlet 8 to the outlet 10 by a conveyor 12 of conventional type, carrying the PA products and operating sequentially, continuously or at variable speed.

  Furthermore, the installation comprises means 14 for controlling its operation, formed for example of a central computer type control unit.

  For example, these control means 14 are adapted to control the flow rate of the cryogenic fluid 4 by means of conventional solenoid valve or proportional valve systems, arranged on the supply line 6 with cryogenic fluid 4 or else for control the forward speed of the conveyor 12 (means for controlling the forward speed of the conveyor 12 well known per se and not shown in the figure).

  Advantageously, the installation also comprises gas extraction means for controlling the flow of gas and the ventilation of the atmosphere inside the enclosure 2. The control means 14 are adapted to control these means. extraction.

  In the embodiment described, the installation further comprises means 20 for determining thickness profiles of food products PA conveyed by the conveyor 12.

  These means 20 are arranged upstream of the inlet 8 of the treatment chamber 2 with respect to the conveyor plane 12.

  The means 20 comprise a projector 22 of a laser beam 24 positioned in a predetermined manner relative to the conveyor 12 and adapted to project the laser beam 24 perpendicularly to the direction of travel of the conveyor 12 and over its entire width.

  The means 20 also comprise a camera 26 arranged in a predetermined manner with respect to the projector 22 and focused on the intersection region of the laser beam 24 with the conveyor belt 12.

  In particular, the orientation of the camera 26 forms a known angle a with the projection axis of the laser beam 24.

  It should be noted that if the embodiment illustrated here shows the presence of a single camera 26, one could use a second camera, placed at an angle -a with the projection axis of the laser beam 24, to complete the reading performed by the first camera, and very advantageous in case of shadow zone caused by the relief of certain food products. The actual profile of the products is then obtained by the resultant of the two profiles delivered by each of the cameras.

  The camera 26 is further adapted to perform a processing of the acquired images in order to deliver a product thickness profile, by detecting the deformations of the laser beam 24 in the region of intersection with the conveyor 12, due to the passage food products PA and the modification of the profile of this intersection during this passage.

  According to the invention, the installation further comprises a sensor 30 for measuring the progress of the conveyor 12, which is for example formed of an optoelectronic sensor disposed on the driving axis of the conveyor 12, in order to undeliver precisely, a measure of its progress.

  By way of illustration, it would also be possible to implement an inductive sensor positioned near the passage of studs, mounted on the drive shaft of the conveyor.

  The measuring sensor 30 is connected to a control unit 32 of the means 20 for determining the thickness profiles of the transported food products, in order to trigger the implementation of these means 20 according to the advancement of the belt of the conveyor 12 .

  Referring to Figure 2, will now be described a general flow chart of the method for determining a quantity of food products transported according to the invention as implemented by the installation described above.

  This method starts with a step 50 of measuring the advancement of the conveyor 12 and corresponds to the delivery, by the sensor 30 to the control unit 32, of a precision measurement of this advance.

  For example, as seen above, these measurements result from the passage of studs, integral with the drive shaft, in front of an inductive sensor, or an optical sensor directly mounted on this axis, or on any other type of sensor well known to those skilled in the art to achieve this kind of measurement.

  Step 50 is followed by a step 60 for determining the thickness profiles of the products transported, a determination made at constant pitch, as a function of the progress measurements made.

  This step 60 comprises a first sub-step 62 of count-15 ment measures delivered in step 50.

  This sub-step 62 makes it possible to transform the measurement period, from the progress of the conveyor 12, into a signal adopting a different period but corresponding to a constant pitch p, measured in the direction of advance of the conveyor 12, desired for the determination of thickness profiles of transported PA food products.

  For example, this substep 52 corresponds to the counting of the progress measurements by the control unit 32 and the triggering of the subscribed substep when a predetermined number of measurements is reached.

  Sub-step 62 is followed by a substep 64 of thickness profile determination control, these commands being issued at variable time intervals corresponding to a determined advancement of conveyor belt 12, forming the constant step p . In the embodiment described, the substeps 62 of enumeration and 64 of control are implemented by the control unit 32 and make it possible to issue a command for determining a thickness profile according to a step constant progress of conveyor belt 12, for example a constant pitch p of 2 mm.

  Each control sub-step 64 is followed by a sub-step 66 of determining a thickness profile of food products PA conveyed by the conveyor 12.

  As previously indicated, in the embodiment described, the determination of this profile is carried out by measuring the deformation of the projection of the laser beam 24 over the entire width of the conveyor 12 perpendicularly to its plane. advancement.

  The laser beam 24 thus materializes in the form of a luminous line perpendicular to the conveyor plane 12 and whose shape in a plane orthogonal to the plane of the conveyor 12 corresponds to the thickness profile of the food products PA on the conveyor 12.

  The camera 26 is adapted to perform a processing of the acquired image so as to directly deliver an image corresponding to the thickness profile of the transported food products PA when receiving the command issued by the control unit 32.

  In particular, the camera 26 is adapted to perform a correction of the image delivered as a function of the predetermined angle α formed with the axis of projection of the laser beam 24.

  This correction, carried out in a conventional manner, allows the means 20 to deliver thickness profiles in real quantities, denoted P i, food products PA transported at constant pitch p, as is schematically represented in FIG. 3.

  Each of the profiles corresponds substantially to the light line of the laser beam deformed by the food products PA.

  As noted above the installation may include a second camera placed at an angle - a, very useful for treating the shadows of some forms of food products.

  The method of the invention then comprises a step 70 of determining an estimate of the quantity of food products PA transported from the profiles P; at constant pitch p, determined in step 60.

  In the embodiment described, this step 70 is implemented in the means 14 for controlling the installation.

  Step 70 firstly comprises a substep 72 for calculating the area of each profile of thickness Pi of food products PA transported with respect to the transport plane of the conveyor 12.

  This substep 72 is performed using conventional calculations of integrals to determine the plane surface of the profile P; rising substantially orthogonal above the plane formed by the conveyor 12.

  Sub-step 72 is followed by a substep 74 of determining a transported volume of PA food products, from an elementary volume for each profile P; corresponding to an assumed volume of product extending between two successive profiles P; and P; + i.

  In a first embodiment, described with reference to FIG. 4A, this sub-step 74 is performed considering a discontinuous variation of the thickness profiles of transported food products PA, so that an elementary volume V; corresponds to the surface of the profile P; multiplied by the length of the constant step p. In the same way, the elementary volume V; +1 corresponds to the surface of the profile multiplied by the same length of constant pitch p. The summation of the elementary volumes thus obtained makes it possible to de-deliver at the end of the substep 74 an estimate of the total volume of the products transported by the conveyor 12.

  According to a second embodiment described with reference to FIG. 4B, sub-step 74 is performed by considering a substantially continuous variation of the thickness profiles of food products PA between two profiles as determined at the end of step 60.

  The elementary volume V '; is then obtained by integration on the distance interval formed by the length of the constant pitch p, of the surface of the profile P; at the surface of the profile P; +1.

  Such an embodiment is more accurate than the embodiment described with reference to FIG. 4A, but nevertheless requires a longer calculation time.

  At the end of the sub-step 74, an estimation of the volume of food products PA conveyed by the conveyor 12 is obtained.

  Step 70 then comprises a substep 76 for converting this volume estimate into a mass estimate obtained by means of information relating to the nature of the food products PA and in particular, in terms of density.

  Typically, such an evaluation is delivered in the form of a unit of mass per unit area or length of conveyor 12 or 5 per unit of time.

  Advantageously, sub-step 76 is followed by a correction sub-step 78, based on the mass density of the elementary product transported.

  Thus, a very aerated product, such as branches broccoli flowers, requires the application of a significant corrective coefficient, to take into account the non-compact nature of the product transported.

  On the contrary, a compact product such as a minced steak does not require correction.

  Such a correction is particularly well suited to the transport of so-called bulk food products, which appear on the conveyor in irregular heaps causing a significant shift between the measured volume and the actual mass transported.

  Advantageously, this correction results from a calibration performed by comparisons between the evaluation and actual mass measurements.

  It therefore appears that the method of the invention makes it possible to determine the quantity of food products PA conveyed by the conveyor 12, in particular by virtue of the production of constant pitch thickness profiles.

  This determination is made in real time, without contact with the food products and regardless of the speed and mode of operation of the conveyor 12.

  This determination makes it possible for the control means 14 to adapt the volume of cryogenic fluid 4 to be injected into the chamber 2, to allow the cooling of the transported PA food products.

  Of course, other applications of this determination can be envisaged, in particular applications at the qualitative level in order to allow better traceability of the products as well as applications in terms of a better billing of the cryogenic liquid consumed by the tunnel.

  Advantageously, the camera 26 is also adapted to deliver information relating to the sharpness of the projection of the laser beam 24 on the conveyor 12, for example from an analysis of the light intensity of the projected laser beam.

  For example, such sharpness information is used to detect cases of vapor reflux at the inlet 8 of the process chamber 2, resulting from inadequate extraction or too much cryogenic fluid.

  The indication of sharpness delivered by the camera 26 is thus used to control the extraction means, and the supply of cryogenic fluid 4 of the chamber 2.

  Furthermore, other embodiments of the invention may be envisaged and in particular, the various elements constituting the installation as described with reference to Figure 1, may be in different forms.

  In the preferred embodiment, all calculations are performed by a central processing unit forming the control means 14 and the control unit 32.

  Alternatively, the product thickness profile determination means is adapted to receive software elements to be configured to directly deliver an evaluation of the amount of food products being transported.

Claims (10)

  1. A method for determining a quantity of food products (PA) transported by a conveyor (12), characterized in that it comprises: - a step (50) for measuring the advancement of said conveyor (12): a step (60) of constant pitch determination (p) of thickness profiles (P;) of transported food products (PA), as a function of the advancement of said conveyor (12); and a step (70) of determining an estimate of the quantity of food products (PA) transported from said constant pitch thickness profiles (Pi) (p) and information relating to the nature of said food products. - res (PA).   2. Method according to claim 1, characterized in that said step (60) of determination of thickness profiles (P;) with constant pitch (p), comprises for each profile (P;): - a substep ( 62) for counting progress measurements of said conveyor (12), and - a substep (64) for controlling the determination of a thickness profile (P;) of transported food products (PA), in order to controlling, when a predetermined number of measurements is reached, determining a thickness profile (P i) at variable time intervals corresponding to a constant pitch (p) of advancement of said conveyor (12).   3. Method according to any one of claims 1 and 2, characterized in that said step (70) for determining an estimate of a quantity of food products (PA) transported comprises: - a substep (72) ) determining the area of each determined thickness profile (P;) in a plane substantially orthogonal to the plane formed by said conveyor (12); a sub-step (74) for determining a volume of food products (PA) transported from the determination of an elementary volume (V; V ') for each determined thickness profile (P;) ; and a substep (76) for determining a mass estimate of food products (PA) transported as a function of said previously determined volume (V; V ';) and the density of the transported food products (PA). .   4. Method according to claim 3, characterized in that said step (70) for determining an estimated amount of food products (PA) transported, further comprises a substep (78) for correcting the estimate of mass of food products (PA) transported according to a corrective coefficient representative of their density.   5. Method according to any one of claims 3 and 4, characterized in that said substep (74) for determining an elementary volume (VI) for each profile of determined thickness, comprises the multiplication of the surface area. a thickness profile (Pi) by the length of said constant pitch (p).   6. Method according to any one of claims 3 and 4, characterized in that said substep (74) for determining an elementary volume (V'1) for each determined thickness profile includes an integral calculation between two successive profiles (P ;, P; +1) along the length of said constant pitch (p).   7. Installation for determining a quantity of food products (PA) conveyed by a conveyor (12), comprising means (20) for determining thickness profiles (P;) of food products (PA) transported on said conveyor (12), characterized in that it further comprises means (30) for measuring the advancement of said conveyor (12), means (32) for controlling said means (20) for determining thickness profiles so to order the determination of thickness profiles (P i) of food products (PA) transported by the conveyor (12) with constant pitch (p) as a function of the progress measurements of said conveyor (12) and means ( 14) determining an evaluation of quantity of food products (PA) transported from said thickness profiles (P;) of food products (PA) and information relating to the nature of said food products (PA).   8 Installation according to claim 7, characterized in that said means (20) for determining thickness profiles (P;) of food products (PA) transported comprise a projector (22) of a laser beam (24), adapted to project a laser beam perpendicular to the direction of advancement of said conveyor (12) and over its entire width, as well as at least one camera (26) arranged in a predetermined manner with respect to said projector (22) and focused on the region of an intersection between said laser beam (24) and said conveyor (12), said camera (26) being adapted to deliver images of deformations of said laser beam (24) projected onto said conveyor (12) due to transported food products (PA) , these images containing said thickness profiles (P;) of food products (PA) transported.   9. Installation according to any one of claims 7 or 8, characterized in that it is adapted to implement the defined method according to   any of claims 1 to 6.   10. Apparatus for treating food articles (PA), comprising a treatment chamber (2) controlled by control means (14), characterized in that it comprises an installation for determining a quantity of food products ( PA) conveyed by a conveyor (12) according to any one of claims 7 to 9, said conveyor (12) being adapted for conveying said food articles (PA) from an inlet (8) to an outlet (10) of said treatment chamber (2) and in that said means (20) for determining the thickness profiles (P i) of transported food products (PA) are arranged upstream of said inlet (8) in relation to the direction of advancement of said conveyor (12) in order to deliver an evaluation of the amount of food products (PA) transported at the inlet of said enclosure (2) and in that said means (14) of piloting are adapted to control the operation of said enclosure (2) according to this evaluation of quantity of food products (PA) transported.