WO2008126119A1

WO2008126119A1 - Filling valve and a method for filling a container

Info

Publication number: WO2008126119A1
Application number: PCT/IT2008/000208
Authority: WO
Inventors: Marco Botti; Roberto Puglia
Original assignee: Sbc Bottling & Canning S.P.A.
Priority date: 2007-04-11
Filing date: 2008-03-28
Publication date: 2008-10-23
Also published as: ITPR20070026A1

Abstract

A filling valve (1) for inserting a filling fluid into a container comprises a piston (3) connected to a shutter (2) and movable with continuity between a position of maximum opening and a closed position of a conduit (4) for the outflow of the filling fluid, an actuator (5) operatively connected to the piston to actuate it, a sensor (7) inserted in said conduit (4) to measure values of flow rate of the fluid delivered by the valve (1) and control means (10) connected to the actuator (5) to regulate the position of the piston (3) as a function of the values of flow rate measured by the sensor (7), said control means (10) comprising an element (9) for tracking the position of the piston (3) operatively connected to the actuator (5) to regulate the position of the piston (3) in feedback, comparing the tracked position with a pre-set position as a function of the measured value of flow rate and consequently modifying the position of the piston (3). Known filling valves are provided with a limited number of positions of the shutter, with no possibility for automatic and accurate regulation of the position of the shutter.

Description

FILLING VALVE AND A METHOD FOR FILLING A CONTAINER

TECHNICAL FIELD AND BACKGROUND ART. The present invention relates to a filling valve and a method for filling a container.

The present invention refers in particular to the food sector, in which filling machines are used, i.e. machines for filling a plurality of containers with a fluid product, in particular liquid or semi-liquid. Filling machines generally comprise a carrousel provided with a plurality of filling valves, each of which is activated and deactivated during the movement of the valve itself integrally with the carrousel. Each filling valve ordinarily comprises a shutter that is movable between an open position and a closed position, being able to assume also intermediate positions, to throttle the flow of product introduced into the containers during the filling operation.

To optimise the filling operation, it is usual to vary the position of the shutter during the filling itself; in particular, the initial and final phase of the filling operations are carried out with the valve in a throttled position, whilst an intermediate filling phase carried out with the valve in the position of maximum opening.

The reduction of the opening of the valve in the initial phase has the purpose of preventing turbulence in the filling fluid. The purpose of reducing the opening of the valve in the initial phase is to prevent undesired releases of fluid from the container and to make the dosing of the product more precise.

The purpose of completing the intermediate filling phase with the valve in the position of maximum opening is to minimise filling times.

The initial and final phases are determined according to the type of filling fluid and of container to be filled, i.e. according to parameters for setting the filling process. For example, for a given fluid and a given container, it may be desirable to perform the filling operation with the valve in throttled position until the container is 10% full, subsequently with the valve completely open until the container is 90% full and, subsequently, with the valve throttled until the completion of the filling operation. To Measure the quantity of fluid introduced into the container, i.e. the progress of the filling operation, generally a flow rate sensor is used, active on the outflow conduit of the valve. To optimise the filling according to the filling product and to the containers to be filled, the intermediate position of the shutter may be varied as well. However, said variation has to be performed in a preliminary calibration step (carried out manually), which is particularly complex and inconvenient to perform. In known systems, filling valves are provided with one or, in some cases, with a plurality of throttled positions, to enable, during the filling operation, to vary the position of the shutter between pre-set positions according to a predetermined logic.

For this purpose, filling valves according to said prior art solutions comprise an actuator, to actuate a piston connected to the shutter movable between the position of maximum opening and the closed position, and control means connected to the actuator to regulate the position of the piston according to the flow rate valves measured by the sensor.

With regard to the actuators, the use of electric motors is also known to vary the position of the piston.

However, said systems have some limitations.

Filling systems in use do not allow to regulate the position of the shutter (i.e. of the piston) with continuity and precisely, in order to vary the opening of the valve according to any pattern, according to the type of container and of filling fluid.

Moreover, prior art valves are inconvenient to use because, to regulate said throttled positions, they require complex calibration procedures, to be performed manually by the operators. Moreover, it should be noted that the use of electric motors to control the position of the piston brings about some problems, e.g. the high operating temperatures of the motors, the need to protect parts under voltage against direct contacts, the large bulk and the wear of the components. DISCLOSURE OF THE INVENTION. An object of the present invention is to eliminate the aforesaid drawbacks and make available a filling valve that enables to carry out the filling operation in optimised, particularly efficient fashion. Said object is fully achieved by the valve of the present invention, which is characterised by the content of the appended claims and in particular in that the control means comprise an element for detecting the position of the piston connected to the actuator to regulate the position of the piston in feedback, comparing the measured position with a pre-set position as a function of the measured value of flow rate and consequently modifying the position of the piston. Another object of the present invention is to make available a particularly flexible and effective filling method.

Said object is fully achieved by the method of the present invention, which is characterised by the content of the appended claims and in particular in that a regulating step takes place in feedback and comprises the following steps:

- detecting the position of the piston;

- comparing the detected position with a pre-set position as a function of the measured value of flow rate;

- modifying the position of the sensor according to said comparison. BRIEF DESCRIPTION OF DRAWINGS.

These and other characteristics shall become more readily apparent from the following description of a preferred embodiment, illustrated purely by way of non limiting example in the accompanying drawing tables, in which: - figure 1 shows a sectioned view of a filling valve according to the present invention;

- figure 2 shows a function diagram of the valve of figure 1;

- figure 3 shows the valve of figure 1 according to an embodiment variant. BEST MODE FOR CARRYING OUT THE INVENTION. In the figures, the reference number 1 designates a filling valve according to the present invention.

The valve 1 is able to be inserted in a filling machine, to insert a filling fluid into a container. The valve 1 comprises a shutter 2 connected to a piston 3 to open and close a conduit 4 for the outflow of the filling fluid from the valve 1.

The piston 3 is movable with continuity between a position of maximum opening and a closed position of the conduit 4.

The valve 1 also comprises an actuator 5 to actuate the piston 3 with continuity between the closed position and the position of maximum opening of the valve 1, and vice versa.

In the preferred embodiment illustrated, the actuator 5 is pneumatic.

Moreover, the piston 3 is preferably a single action piston co-operating with a spring 6. The spring 6 forces the piston 3 to remain in the closed position, or, alternatively, in the fully opened position, in the absence of actions by the actuator 5. The actuator, blowing in air, actuates the piston 3 towards the open or, alternatively, the closed position, contrasting the action of the spring 6. Note that the valve 1 has not end stops able to define intermediate positions of the piston 3, i.e. the piston 3 is free to slide without obstacles assuming all positions between the closed and the fully opened position.

This enables, advantageously, to actuate the piston 3 with continuity in particularly simple and robust fashion. Moreover, the valve 1 comprises a sensor 7 (not shown in figure 1, but shown schematically in figure 2) to measure values of flow rate of the fluid delivered by the valve. Said sensor 7, of a substantially known kind, is preferably inserted in the conduit 4 for the outflow of the filling fluid.

The filling valve also comprises a board 8, able to receive at its input a signal representing the flow rate value measured by the sensor 7 and to derive (substantially by means of a time integration process) the quantity of product (i.e. of filling fluid) present within the container at a given instant.

In the preferred embodiment, the board 8 is analogue. The board 8 is programmed to associate to the flow rate values received at its input corresponding desired values of opening of the valve 1, i.e. desired positions for the shutter 2 (or for the piston 3). The board 8 is operatively connected to the actuator 5 to drive it, on the basis of said desired values of opening for the valve 1, obtained as a function of the flow rate values received as inputs. Originally, the board 8 comprises a memory containing at least one preset pattern of the position of the piston 3 as a function of the quantity of filling fluid inserted in the container.

In particular, advantageously, said memory comprises a plurality of preset patterns; moreover, the board 8 is provided with means for selecting one of said patterns as a function of the filling fluid (constituted, for example, by a logic integrated in the board 8 or by an appropriately programmed PLC). The valve 1 also comprises, originally, an element 9 for tracking the position of the piston 3. Said tracking element 9 is connected to the board 8 and hence, through the board 8, it is operatively connected to the actuator 5 to regulate the position of the piston 3 in feedback, i.e. on the basis of a comparison between the measured position of the piston 3 and said desired position.

Thus, said desired position is obtained as a function of the measured flow rate value, on the basis of a pre-set pattern of the position of the piston 3 as a function of the quantity of filling fluid inserted in the container, said pattern being selected from a plurality of patterns. This enables, advantageously, to take into account the type of the container and of the filling fluid, automatically and with no need for complicated preliminary adjustment steps. Therefore, the board 8 sends a command signal to the actuator to actuate the piston according to the result of said comparison between the measured position of the piston and its desired position (for the instantly measured flow rate value).

The board 8, the sensor 7 and the tracking element 9 define control means 10 connected to the actuator 5 to regulate the position 3 of the piston as a function of the flow rate values measured by the sensor.

Said tracking element 9 is constituted, for example, by a linear transducer operatively connected to the piston 3 (e.g. a feeler pin). In particular, in the preferred embodiment illustrated, the tracking element 9 and the actuator 5 are mutually integrated, in the form of an electrical positioner. Note that electrical positioners, in themselves, are known in the sector of monitoring the level of liquid present within tanks.

This enables, advantageously, a drastic reduction in bulk and, at the same time, it allows to perform a particular precise control. With regard to the control means 10 in general and, in particular, the board 8, they are constructed in analogue or, alternatively, in digital fashion.

With regard to the type of feedback control performed, the board 8 is programmed to perform preferably a continuous control, assuring a particularly high level of precision.

According to an embodiment variant shown in figure 3, the valve 1 provides the following.

The piston 3 is a double action piston and it is actuated by a pneumatic actuator 5 commanded by an electrical valve or by a bank of electrical valve.

The tracking element 9 consists of a transducer comprising a first portion associated to the piston 3 and movable integrally therewith and a second portion integral to the fixed part of the valve 1. The first portion and the second portion interact electrically (e.g. by means of a potentiometer), optical or magnetic, making available an electrical output signal representative of the position of the piston 3 relative to a fixed portion of the valve 1.

The board 8 is an electronic board connected to the tracker 9 and to the electrical valve to control in feedback the position of the piston 3, the board 8 constituting at the same time said control means 10. The present invention also makes available a method for filling a container with a fluid through a filling valve 1 provided with a piston 3 connected to a shutter 2 and movable between a position of maximum opening and a closed position of a conduit 4 for the outflow of the fluid. Said method comprises the following steps:

- actuating the piston 3 to an open position;

- measuring a value of flow rate of the fluid delivered by the valve by means of a sensor 7;

- regulating the position of the piston 3 as a function of the measured flow rate value.

The regulating step in turn originally comprises the following steps:

- tracking the position of the piston 3;

- comparing the detected position with a pre-set position as a function of the measured value of flow rate; - modifying the position of the sensor according to said comparison.

Said pre-set position (i.e. the desired position) is a position set according to a desired pattern for the instantaneous position of the shutter 2 as a function of the filling level of the container.

In this light, note that said method also comprises, originally, the following steps, subsequent to the tracking step:

- deriving the quantity of product inserted into the container, integrating the flow rate of filling fluid delivered by the valve in time (from the start of the filling operation);

- associating a desired (pre-set) value of opening for the shutter 2 as a function of said derived quantity of product, on the basis of a pre-set pattern.

Therefore, the present invention advantageously enables to manage in optimised fashion the filling of a container by means of a filling fluid, performing a feedback control of the position of the shutter 2, i.e. of the position of the valve, said position being variable with continuity between a position of maximum opening and a closed position.

Said control is preferably continuous, to assure a particularly high level of precision.

The present invention is particularly flexible, with the possibility of treating filling fluids and different containers in optimised, automatic fashion with no need for regulation and calibration operations.

Moreover, the valve 1 according to the present invention is particularly simple and rugged, because it does not require the use of electric motors or reduction gears.

Claims

1. Filling valve (1) for inserting a filling fluid into a container, comprising:

- a piston (3) connected to a shutter (2) and movable between a position 5 of maximum opening and a closed position of a conduit (4) for the outflow of the filling fluid;

- an actuator (5) operatively connected to the piston to actuate it;

- a sensor (7) inserted in said conduit (4) to measure values of flow rate of the fluid delivered by the valve (1); o - control means (10) connected to the actuator (5) to regulate the position of the piston (3) as a function of the value of flow rates measured by the sensor (7), characterised in that the control means (10) comprise an element (9) for tracking the position of the piston (3) operatively connected to the

5 actuator (5) to regulate the position of the position (3) in feedback, comparing the tracked position with a pre-set position as a function of the measured value of flow rate and consequently modifying the position of the piston (3).

2. Filling valve as claimed in claim 1, wherein said actuator (5) is ao pneumatic actuator.

3. Filling valve as claimed in claim 2, comprising a spring (6) contrasting said actuator (5), said piston (3) being a single action piston.

4. Filling valve as claimed in any of the previous claims, wherein said element (9) for tracking the position of the piston (3) is a linear5 transducer operatively connected to the piston (3).

5. Filling valve as claimed in any of the previous claims, wherein the control means (10) comprise a memory containing at least one pre-set pattern of the position of the piston (3) as a function of the quantity of filling fluid inserted in the container.

6. Filling valve as claimed in claim 5, wherein said memory comprises a plurality of pre-set patterns, the control means (10) being provided with means for selecting one of said patterns as a function of the filling fluid.

7. Filling valve as claimed in any of the previous claims, wherein the piston (3) is movable with continuity between said closed position and said position of maximum opening of the shutter (2).

8. Filling valve as claimed in any of the previous claims, wherein the control means (10) comprise a board (8) connected to the sensor (7) to receive a signal representative of the flow rate of the fluid delivered instantaneously by the valve (1) and output a signal representative of an instantaneous value of the desired position of the piston (3).

9. A filling valve as claimed in any of the previous claims, wherein the piston (3) is a double action piston driven by an electrical valve.

10. A filling valve as claimed in claim 9, wherein the tracking element (9) comprises a portion integral with the piston (3) interacting with a portion integral with the fixed portion of the valve (1).

11. A method for filling a container with a fluid through a filling valve (1) provided with a piston (3) connected to a shutter (2) and movable between a position of maximum opening and a closed position of a conduit for the outflow of the fluid, comprising the following steps: - actuating the piston (3) to an open position;

- measuring a value of flow rate of the fluid delivered by the valve (1);

- regulating the position of the piston (3) as a function of the measured flow rate value, characterised in that said regulating step is performed in feedback and comprises the following steps:

- detecting the position of the piston (3);

- comparing the detected position with a pre-set position as a function of the measured value of flow rate; - modifying the position of the piston (3) according to said comparison.

12. Method as claimed in claim 11, comprising a preliminary step of selecting, based on the type of fluid treated, of a pre-set pattern of the position of the piston (3) as a function of the flow rate values of the fluid delivered by the valve.