Method and device for controlling the amount of filling material in a weight-responsive filling machine.

The present invention relates to filling facilities container, more particularly to a method and a container filling material dosing device in a filling machine weight assay.

The weight filling is becoming more and more in filling plants with liquid or divided materials, for example in food and pharmaceutical industries, because of obtaining more accurate and reliable results compared to volumetric metering installations . This technique requires the development, for each filling head, a weighing scale associated with detection means for controlling the filling head to the weight of actually issued filler. So far, because of the severe conditions of use such materials, it was anticipated, associated with a mobile element of the balance, a type detection means for proximity detection, as described in French Patent No. 2,098. 780 in the name of the inventor. This technique to control all or nothing is entirely satisfactory with regard to the robustness of the reliability of use but has the disadvantage of having to take into account and correct otherwise fluctuating parameters of the filling installations, such as for example those under the calibration of empty containers or the weight of the dispensed material column between the outlet of the filling head and the container, requiring the use of the correction means of proximity sensors as described for example in french patent application No. 78/1787 on behalf of the applicant.

The present invention is precisely to provide a method and a container filling material metering device in filling machines weight filling, which obviates the above drawbacks, providing, while maintaining high reliability in use, a great flexibility of use by incorporating programmable logic components and for modulating the operating conditions of the installation, or by injecting specific parameter of image data, either automatically during operation

To do this, the-method according to the present invention, implemented in a filling machine comprising at least one filling station / weighing with a filling head, a crew weighing balance parallelogram, detection means being associated with the provision _tif weighing for controlling the filling head, is mechanically coupled to a movable member of the crew of the balance a force sensor and to transmit continuously the output signal of the sensor to a logic-programmable memory unit providing a control signal to the filling head when the detected weight value reaches a value derived and corrected by the nominal value en- 'tered.

According to another feature of the present invention, the metering device for such a filling machine, more particularly but not exclusively of the type with multi carousel comprising at least one filling station with a controllable filling head and a weighing scale in parallelogram crew, detection means being associated with the weighing scale to provide a control signal to the filling head comprises a force transducer mechanically coupled to a movable member of the crew of balance and connected to a first- input of a programmable logic unit memory device comprising a second control input and storage process, and whose output is connected to the filling head.

Besides the problems of severe conditions of use, in terms of temperature and moisture, filling machines, particularly of the carousel type, have proved far rebel to the integration of electronic components particularly because of high levels of vibration over wide frequency ranges encountered in such machines.La plaintiff, with its experience of many years in the field of weight filling, and after many experiments, realized that the use of a force transducer, for example strain gauge type, could not be done in combination with a crew weighing balance parallelogram, whose robustness and ability to "cash in" parasitic couples inevitably induced on the measurement platform in the rate of installations has allowed gran however, thanks to the low inertia of these scales, equipped with hinge bearings, measurement capabilities extremely fines.En effect, particularly in filling carousels further inertial problems relating to the rotary nature of the installation, the containers, for example bottles, to be properly positioned beneath the filler heads are set up dynamically during charging on the filling carousel by flanges centering, such as those shown in Figure 1 and then transmit important parasites and variable torque the crew to weigh that make illusory because, in addition, significant changes in location of the vessel's center of gravity, a mechanical coupling live between the stacker / weighing and a force transducer.

According to another feature of the present invention, the force sensor being sensitive blade type and strain gauge, the mechanical coupling between the sensor and the moveable member or scourge of the crew of the balance is achieved by a cable traction.

Indeed, due ABOVE born rate of vibration, the Applicant has found that the signal output of a transducer operating in compression was almost unusable in a filling machine, while the tensile load, especially by a flexible cable , reduces by a factor of 10 the effects of vibration on the sensitive plate of the sensor.

Other features and advantages of the present invention will become apparent from the following description of an embodiment given as an illustration but not limitation, in conjunction with the accompanying drawings, wherein:<ul><li>Figure 1 is a schematic sectional view of a weighing station of a filling carrousel equipped weight dosing device according to the present invention; and</li><li>Figure 2 is a filling plan.d'une such an installation in order to assess the sequences of the dosage control method with the device of Figure 1.</li></ul>

In Figure 2, one recognizes a filling carousel multi 1 supplied in containers to be filled by an upstream transfer carousel 2 taking the containers 3 on a linear conveyor 4, the filled containers in the filling carousel 1 being removed from the latter and recirculated on the linear conveyor 4 by an output transfer carousel 5. 1 filling carousel is provided with a number-weighing stations (typically 12 or 24) of the type shown in Figure 1.

In this figure 1, we recognize the filling head 6, for example of the type of electromagnetic valve control, located at the base of a receiver plate 7 of a weighing scale of the parallelogram to crew type generally referenced 8 . the balance 8 consists of a support column 9, mounted on a frame 10 secured to the hollow shaft 11 of the carousel, a floating column 11, and a lower beam 12, .the parallelogram being completed by a top rail 13, these various elements being articulated relative to each other by ball bearing such as that featured 14. According to the present invention, the scale 8 has a particularly compact configuration, with the average height of the upper columns or twice the length of the sleepers. The plate 7 is connected to the floating column 11 by a hollow tubular upright 15.

According to one aspect of the present invention, to adjust the leveling of the scale plate 7 with the plate 16 of the carousel, the amount 15 has its lower end _'higher on an evolutive cam surface 17 controllable by a shaft 18, the post 15 being attached to the spar buoy 11, once upgraded, by clamping plates 19. The different scales of the carousel 1 are traditionally housed in a a housing comprising top cover 20 and an outer peripheral skirt 21. to avoid splashing of the filling material inside the casing, the amount 15 of the tray 7 is associated a roller labyrinth system 22 as shown in FIG ' l. The tray 7 is traditionally equipped open flanges 23 centering containers located, for bottles at the bottle neck of these-and inducing problems coupled above parasites. The balance of gear 8 may be supplemented by a counterweight 24 mounted on an extension of the beam 12, although this counterweight induces problems of mass moments require mass compensation of the other side of the balance, as a counterweight being le.capteur with unnecessary force 1a according to this invention.

The force transducer 25, having a blade 26 sensitive strain gauge is mounted on a yoke 27, substantially in the extension of the top rail 13, the bracket 27 being secured by the inner ends of its side legs to the column bracket 9. According to the present invention, this supporting column 9 is also fixed to the frame 10 with the interposition of resilient elastomeric elements 28, for example of the type called "silent block". The sensitive blade 26 of the sensor 25 is mechanically coupled to the outer end of the beam 12 by a cable 28 normally pulling on the sensitive blade in a direction perpendicular to the plane thereof. According to one aspect of the present invention, the cable 28 passes through the orifice of the sensitive plate 26 and a coil spring 29 at the upper end of which is connected to the adjacent end of cable 28, the spring bearing 29 by a cup profiled on the blade 26. the spring 29 is of high stiffness type and designed to begin to collapse under the application of a compressive force of about 20 kg, ie much higher normal weight containers filled to weigh in the balance. For weight measuring containers of the order of 2 to 5 kg, the sensor 25 is selected with a sensitive blade of the class of 20kg. To prevent accidental damage to the sensitive blade, angular lé down the scourge 12 is limited by an adjustable stop 30.

According to the present invention, the output of the force sensor 25 is fed by a line 31 to a measuring input 32 of a programmable logic microprocessor unit 33, housed in a support with damper below crew, 8. The balance unit _'memory logic 33 includes at least a second input 34, allowing injection in memory of specific data and registration of no determined program. A calculation output 35 of the logic unit 33 is connected by a line 36, to the filling head 6, for selectively controlling the opening and closing depending on requirements developed by the logic unit 33, typically when the weight value measured by the sensor, converted to digital, reaches a displayed internal value.

The dosage control method of the present invention will now be explained in more detail with reference to the layout diagram of Figure 2. At the beginning of a filling cycle, the data specific to this cycle, including the weight values desired by the type of product to fill and dimensions of the containers are injected into the inlet 34 of 33 LUNs balan these different carousel filling stations 1. for example, suppose the desired weight of the filling material container is 1000 grams. With the method of the invention, it is not concerned to make a prior determination of average tare containers to fill no more than the average value of the liquid column or divided product mentioned in the introductory part of the description.On simply assigns LUNs 33 in an initial desired value less than the required weight, eg 900 grams. A first passage of containers provided by the linear conveyor 4, allows for successive filling stations, the associated sensors 25 transmit to the logic units 33 corresponding, during the first phase of angular transfer AB from the loading zone A ( AB angle of about 15 to 20 °) - measuring signals making them take into account the weight of the tare constituted by each vessel, allowing re- 'stall registers the logical unit 33 cause it to effect a continuous measurement net weight when the angular transfer phase BC upstream of the discharge zone_D, That is to say, before the structural elements of the transfer carousel 5 will start coming into contact with the containers. The CD angle is selected in the range of 10 to 15 °. Depending voluntarily minus calibration of this start cycle, the logic unit 33 will be provided by its output 35, a signal for closing the head 6 when the value detected by the sensor 25 - offset from the initial recognition of tare - reaches 900 grams, and that, upstream of the angular zone C. once the order of the head 6 is made, the logic unit 33 records the actual weight of the filled container, and during the transfer angular phase vacuum DA, performs the comparison with the desired value recorded for the correct taking into account specific parameters and filling cycle considered, such as the weight of material column or the impact strength thereof according to the filling rate , so that the value taken into account in the next cycle to control the closure head will be different from the exact desired value and the initially displayed value to provide, from this second cycle, the offset of the calibration being performed each time when transferring AB, the exact weight required; in this case 1000 g ± 5 grams.

The method according to the present invention further allows to take into account unwanted amounts of material on the plates 7, for example from previous containers for leaks and to actuate, via an outlet 37, an alarm device and / or display, signaling the malfunction of a head as detected during the comparison phase in the DA angular transfer phase.

Although the present invention has been described, in relation to particular embodiments, -it does is not limited thereto but is instead subject to changes and variations which occur to those skilled in the art.