Abstract:
The method for filling containers comprises the following stages: closing an exhaust duct in a calibrated manner ( 61,62 ) according to a calibration to an exhaust pressure that is lower than the distribution pressure; placing into position a container to be filled; opening a distribution valve ( 24 ) and keeping it open until the closure of an exhaust check valve ( 46 ); closing the distribution valve ( 24 ).

Description:
[0001]    The present invention relates to a method for filling containers to a constant level with a still or a sparkling liquid and a filling nozzle for the implementation of this method. 
       BACKGROUND TO THE INVENTION 
       [0002]    For the purpose of filling containers to a constant level with a still liquid, filling nozzles are previously disclosed comprising an annular connection part configured to provide a liquid-tight support with a neck of a container and to demarcate a distribution zone; a distribution tube connected to a source of supply of a liquid under a distribution pressure by means of a distribution valve and discharging into the distribution zone; an exhaust duct discharging on the one hand into the distribution zone, and on the other hand via a vent orifice, and an exhaust check valve controlled by a liquid level sensor inside the exhaust duct, interposed in the exhaust duct between the distribution zone and the vent orifice. When filling a container, the air that is present inside the container is expelled by the liquid as it is introduced into the container and escapes via the vent orifice. When the liquid reaches the lower extremity of the exhaust duct, the liquid rises in the exhaust duct and causes the closure of the exhaust check valve. The distribution valve is then closed, and the container is separated from the annular connection part in such a way that the liquid that is present inside the exhaust duct returns into the container. 
         [0003]    These filling nozzles cannot be used for the packaging of sparkling liquids, that is to say liquids containing a gas dissolved in the liquid, because of the de-gassing which occurs at the time of the introduction of the liquid into the container. 
         [0004]    Also familiar, in particular from the document U.S. Pat. No. 3,946,770, and from the document U.S. Pat. No. 4,206,789, are devices comprising a highly complex system of tubes and valves positioning the filling nozzle in relation to a pressure vessel containing the liquid to be packaged in such a way as to place the supply vessel and the container under the same pressure. During filling, the air that is initially present inside the container is returned to the supply vessel and thus risks causing pollution of the liquid to be packaged. Furthermore, it is difficult to perform effective cleaning because of the complexity of the circuits. 
       OBJECT OF THE INVENTION 
       [0005]    One aim of the present invention is to propose a method and a filling nozzle for implementing this method, in order to perform the filling of containers with a still or a sparkling liquid in a simple manner. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0006]    With a view to the achievement of this aim, a method is proposed according to the invention for filling containers to a constant level by means of a filling nozzle comprising:
       an annular connection part configured to provide a liquid-tight support with the neck of a container, and to demarcate a distribution zone,   a distribution tube connected to a source of supply of a liquid under a distribution pressure by means of a distribution valve and discharging into the distribution zone,   an exhaust duct discharging on the one hand into the distribution zone, and on the other hand via a vent orifice, and   an exhaust check valve controlled by a liquid level sensor inside the exhaust duct, interposed in the exhaust duct between the distribution zone and the vent orifice, the method comprising the stages of:   closing the exhaust duct in a calibrated manner according to a calibration to an exhaust pressure that is lower than the distribution pressure, between the exhaust check valve and the vent orifice,   placing into position a container to be filled, resting against the annular connection part,   opening the distribution valve and keeping it open until the closure of the exhaust check valve,   closing the distribution valve,   releasing the container from the annular connection part.       
 
         [0016]    Thus, at the time of the introduction of the liquid into the container, the air that is present inside the container is compressed until it reaches the calibration pressure so that, in the case of a sparkling liquid, the pressure inside the container opposes a de-gassing of the liquid. At the time of the closure of the distribution valve and the disengagement of the container, the gas under pressure that is trapped between the exhaust check valve and the calibrated valve causes the opening of the exhaust check valve and an accelerated return flow of the liquid that is present inside the exhaust duct towards the container. 
         [0017]    According to an advantageous version of the invention, the method comprises in addition a stage of injecting into the exhaust duct, after placing a container in position, a gas at a pressure not exceeding the exhaust pressure. Thus, in the case of a still liquid, the introduction of an inert gas into the container permits the effective level of oxygen to be reduced. By way of example, the introduction into a container at atmospheric pressure of nitrogen at a pressure of 200 kPa causes the proportion of oxygen trapped to fall to one third of its initial value. 
         [0018]    The invention also relates to a filling nozzle comprising:
       an annular connection part configured to provide a liquid-tight support with the neck of a container, and to demarcate a distribution zone,   a distribution tube connected to a source of supply of a liquid under a distribution pressure by means of a distribution valve and discharging into the distribution zone,   an exhaust duct discharging on the one hand into the distribution zone, and on the other hand via a vent orifice,   an exhaust check valve controlled by a liquid level sensor inside the exhaust duct, interposed in the exhaust duct between the distribution zone and the vent orifice, and   a calibrated valve installed between the exhaust check valve and the vent orifice.       
 
         [0024]    According to an advantageous version of the invention, the filling nozzle comprises a gas injection device arranged to permit the injection of gas into a container resting against the annular connection part. 
         [0025]    In this case, the gas injection device preferably discharges into the exhaust duct between the exhaust check valve and the vent orifice. 
         [0026]    Thus, the gas injection device is not reached by the liquid during filling of the container, which simplifies the cleaning of the filling nozzles. 
         [0027]    According to another advantageous aspect of the invention, the filling nozzle comprises a connecting tube discharging on the one hand into the distribution tube, and on the other hand into the exhaust duct, between the exhaust check valve and the vent orifice, and a valve installed in the connecting tube. Thus, at the time of cleaning the filling nozzle, it is sufficient to pass a cleaning liquid via the distribution tube and to open the valve installed in the connecting tube in order to assure the complete cleaning of the filling nozzle, including the exhaust duct and the exhaust check valve. 
         [0028]    Furthermore, the quantity of liquid which rises in the exhaust duct and then returns into the container is a function of the volume of the float assuring the closing actuation of the exhaust check valve. This poses a problem to the extent that the liquid serving to raise the float then returns into the container and runs the risk of being polluted during its passage through the exhaust duct. It is desirable, therefore, to minimize the volume of the exhaust check valve. 
         [0029]    According to yet another aspect of the invention, the exhaust check valve is arranged inside a closed enclosure having an upper wall comprising an exhaust orifice surrounded by an upper seat for the exhaust check valve, and the exhaust check valve is a non-return valve installed in such a way as to slide in a valve guide comprising a guide tube having a lower extremity communicating with the exhaust duct and an upper extremity centred on the upper seat of the exhaust check valve, the exhaust check valve furthermore being installed in the guide tube with a free play creating a sufficient loss of pressure for the exhaust check valve to be forced back in the manner of a piston by liquid arriving via the exhaust duct. Thus, an exhaust check valve with a dimension only slightly larger than the upper seat is sufficient to assure the liquid-tight closure of the exhaust orifice in such a way that the volume of liquid necessary for the actuation of the exhaust check valve is very small. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0030]    Other characteristics and advantages of the invention will be appreciated from reading the following description of a preferred, non-limitative mode of implementation of the method according to the invention and of the filling nozzle permitting this implementation, with reference to the accompanying figures, among which: 
           [0031]      FIG. 1  is a schematic side view of a filling carousel equipped with filling nozzles according to the invention, 
           [0032]      FIG. 2  is a highly enlarged cross-sectional view of the box A in  FIG. 1 , according to the line II-II in  FIG. 1 , 
           [0033]      FIG. 3  is a highly enlarged cross-sectional view of the box B in  FIG. 1 , according to the line III-III in  FIG. 1 , 
           [0034]      FIG. 4  is an enlarged perspective view of the exhaust check valve guide according to the invention, 
           [0035]      FIG. 5  is a further enlarged view of the box C in  FIG. 3 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0036]    With reference to  FIG. 1 , the filling carousel according to the invention comprises an annular supply collector  1  supplied with a liquid under pressure via radial tubes  2  having an extremity connected to the supply collector  1  and an opposite extremity connected to a rotating joint  3  assuring a connection to a source of supply with a liquid under pressure symbolized by a pump  4  associated with a storage vessel  5 . As illustrated in  FIG. 2 , the collector  1  is formed by an annular groove  6  provided in a plate  7 , and closed by an annular cover  8  adequately secured to the plate  7  by means of bolts (not illustrated here) extending into drillings  9 , the sealing between the plate  7  and the cover  8  being assured by means of o-rings  10  and  11 . Filling nozzles  12  are suspended beneath the plate  7 . Each filling nozzle  12  comprises a nozzle body  13  traversed by a vertical bore  14  comprising at its lower part a recess  15 , inside which there is installed an annular joint  16  forming an annular connection part configured to provide a liquid-tight support with the neck of a container  17 . 
         [0037]    A distribution tube formed by a rectilinear tube  18  is installed in the bore  14  and is maintained in place by an o-ring  19  compressed by a screwed bushing  20 . The lower extremity of the distribution tube  18  extends into the interior of the container, in which it defines a distribution zone  21 . The upper extremity  22  of the distribution tube  18  is fixed beneath the plate  7  and is connected to the supply collector  1  via a drilling  23 , by means of a distribution valve  24 . In the illustrated embodiment, the distribution valve  24  comprises a ball  25  resting on a bowl  26  installed in a liquid-tight manner across the distribution tube  18  and comprising a distribution orifice  27  having a diameter smaller than that of the ball  25 . The ball  25  is actuated by a magnetic actuator comprising a finger  28  carried by a cylindrical magnetic armature  29  arranged in the interior of the distribution tube  18  and the position of which is determined by a magnetic ring  30  installed in an axially mobile manner in relation to the distribution tube  18  and surrounding the latter at the level of the magnetic armature  29 . The position of the magnetic ring is determined by an actuating device comprising in this case a guide roller  31  fixed to the magnetic ring  30  and interacting with a guide cam  30 . The finger  28  extends coaxially in relation to the distribution orifice  27  of the bowl  26  in such a way that, as a function of the axial movements of the magnetic armature  29 , the ball  25  is either resting against the edge of the distribution orifice  27  in order to assure a closure of the supply tube  18 , or is moved away from this position by the finger  28  in such a way that liquid under pressure is able to flow through the distribution orifice  27  in the distribution tube  18 . 
         [0038]    In its lower part, the bore  14  comprises a recess  33 , installed in which is a tube  34  which extends coaxially in relation to the distribution tube  18  by being spaced from the latter, and which extends downwards to a point close to the lower extremity of the distribution tube  18 . At its upper extremity, the tube  34  is pierced by an orifice  35  which coincides with a drilling  36  in the nozzle body  13 . The tube  34  and the drilling  36  thus define a part of an exhaust duct, the upper extremity of which discharges into an exhaust control device  37 . 
         [0039]    In the illustrated embodiment, the exhaust control device  37  comprises a body  38  comprising a longitudinal drilling  39 . At its lower extremity, the drilling  39  discharges into a bore  44  having a diameter greater than the drilling  39  in such a way that the recess between the drilling  39  and the bore  44  defines an upper seat  45  for a non-return valve formed here by a steel ball  46 . The expression non-return valve in the sense of the invention is used here to denote a valve having a sufficient density for it to be incapable of being carried by the liquid to be packaged. The ball  46  is installed in an exhaust check valve guide formed in this case by a bushing  47  having a lateral cylindrical wall  48  of the same diameter as the bore  44 , provided with an annular flange  49  having identical dimensions to a recess  50  in the bore  48  such that, after press-fitting of the bushing  47  in the body  38  and its fixation on the body  13  by means that are not represented here, the bushing  47  is installed in a liquid-tight manner in the body  38  and is applied in a liquid-tight manner to the body  13 . The bushing  47  thus delimits, together with the bore  48 , an enclosure  67  provided with an exhaust orifice  45 . 
         [0040]    The bushing  47  comprises a central drilling  51  that is coaxial with the drilling  39  in the body  38  and has the same diameter as the latter. The lower extremity of the drilling  51  coincides with the upper extremity of the drilling  36  in the bloc  13 . In the case of the lower extremity of the drilling  39 , the bushing  47  comprises an upper drilling  52 , coaxial with the drilling  51  forming a guide tube or the ball  46  and having a diameter greater than that of the ball, adapted in order for the free play between the ball  46  and the drilling  52  to create a loss of pressure sufficient for the ball  46  to be forced back in the manner of a piston by liquid arriving via the drilling  36 . A free play of between half a tenth of a mm and one tenth of a mm is satisfactory in practice. The recess between the drilling  51  and the bore  52  defines a lower seat  55  for the ball  46 . The lower seat  55  is preferably situated at a distance away from the upper seat such that the course d of the ball  46 , between the low position represented as a solid line in  FIG. 5  and the high position represented as a dashed line, does not exceed the radius of the ball  46 . 
         [0041]    Furthermore, the bushing  47  comprises a radial drilling  54  of the same diameter as the drilling  51 , associated with a lateral notch  53  having a section above the drilling  51  in order to delimit, together with the lateral wall  48  of the enclosure  67 , a by-pass tube extending parallel to the guide tube  52  and having a lower extremity discharging below the ball  46  and an upper extremity discharging above the ball  46  when the latter is in a rest position resting against the lower seat  55 . The by-pass tube preferably has a volume greater than a volume swept by the exhaust check valve between a low position and a high position. 
         [0042]    With reference to  FIG. 3 , the body  38  in addition comprises a drilling  56  oriented transversally to the drilling  39  and associated with a bore  57 , into which is screwed a bushing  58 , the central tube  59  of which bushing forms a part of the exhaust duct and discharges to the exterior of the body  38  via a vent orifice  60 . The bore  57  has a diameter greater than the drilling  56 , and the recess produced by this means forms a seat for a ball  61  biased towards the latter by a spring  62  arranged in the central tube of the bushing  58 , and the bearing force of which is determined by the tightening of the bushing  58 . The bushing  58 , the ball  61  and the spring  62  thus form a calibrated valve between the exhaust orifice  45  and the vent orifice  60 . 
         [0043]    Still with reference to  FIG. 3 , the upper extremity of the longitudinal drilling  39  is equipped with a device for injecting gas under pressure comprising a bushing  40 , installed in which is a non-return valve  41 . The bushing  40  is connected to a source of gas under pressure, such as a nitrogen cylinder  42 , by means of a valve  43 , the position of which is controlled by an actuating device such as a guide roller associated with a cam, not illustrated here. 
         [0044]    Furthermore, the filling nozzle according to the invention comprises a connecting tube  63  discharging on the one hand into the distribution tube  18  and on the other hand into the drilling  39 . A valve  64  is installed in the connecting tube  63 , and its position is determined by a control device such as a guide roller  65  associated with a retractable cam  66 . 
         [0045]    The device thus described serves to implement the method according to the invention as described below. The calibrated valve  61  is first of all regulated so as to close the exhaust duct according to a calibration to the maximum exhaust pressure that it is wished to achieve inside the container in the course of its filling, the said calibration pressure being lower, of course, than the distribution pressure. A container to be filled is positioned resting against the annular connection part. If necessary, as a function of the desired filling conditions, a gas at a pressure not exceeding the exhaust pressure is injected into the exhaust duct. It should be noted in this respect that, because of its weight, the exhaust check valve  46  normally rests against the lower seat  55 . Furthermore, because of the existence of the by-pass tube  53  and the dimensional variation between the drilling  51  and the bore  52 , the exhaust check valve is held against the lower seat  55  with a force which increases in proportion to the level of the pressure inside the exhaust duct. 
         [0046]    The distribution valve is now open, and the liquid then flows into the container at a rate of flow which is a function of the difference between the distribution pressure and the pressure inside the container. When the liquid reaches the lower extremity of the tube  34 , as illustrated in  FIG. 3 , the liquid rises in the exhaust duct. When it reaches the bushing  47 , the liquid rises simultaneously in the drilling  51  and in the by-pass tube  53 , although because of the difference in volume between the by-pass tube and the drilling  51 , the liquid rises more rapidly in the drilling  51  than in the by-pass tube in such a way that the exhaust check valve is forced against the upper seat  45  before the liquid reaches it via the by-pass tube. When the exhaust duct is closed by the exhaust check valve  46 , the liquid ceases to flow into the container. The distribution valve  25  is then closed, and the container is lowered in order to release it from the joint  16 . The neck of the container is now vented and, because of the gas under pressure trapped between the calibrated valve  61  and the exhaust check valve  46 , the latter is pushed abruptly downwards and the liquid that is present inside the exhaust duct is expelled towards the container. 
         [0047]    Of course, the invention is not limited to the described embodiment, and variant embodiments can be included without departing from the context of the invention as defined by the claims. 
         [0048]    In particular, even though the invention has been described in relation to a filling nozzle connected to a device for injecting a gas under pressure, which permits a high pressure to be reached very rapidly in the interior of the container, the method according to the invention can be implemented without the prior injection of gas under pressure, the pressure ultimately reached inside the container being solely a function of the quantity of liquid introduced into the container and the calibration of the valve  61 . 
         [0049]    Although the invention has been described in relation to a filling nozzle comprising a connecting tube  63  between the liquid distribution tube and the exhaust duct in order to simplify the washing circuit and the washing operation, provision can also be made for the separate supply of a cleaning liquid to the distribution tube on the one hand, and to the exhaust duct on the other hand, by installing a device for the injection of a cleaning liquid on the body  37 . Whether the washing product is fed into the exhaust circuit via the connecting tube or via an independent injection device, it may in any event be recovered below the filling nozzle via a common collector on the distribution tube and on the exhaust duct.