Abstract:
A filling device ( 10 ) includes a tubular body ( 12 ) including, in an upper section ( 14 ), a feeding chamber ( 18 ), and provided with a nozzle ( 20 ) for the flow of the liquid, wherein a liquid feeding conduit ( 22 ) leads into the feeding chamber ( 18 ) through a feeding orifice ( 24 ), and including a plug ( 26 ) which is controlled in axial sliding inside the tubular body ( 12 ), between an open position and a closed position. The device includes a servo valve ( 42, 142 ) coaxial to the plug ( 26 ) which is arranged in the upper section ( 14 ) of the tubular body ( 12 ). The servo valve ( 42, 142 ) includes a wall ( 44, 144 ) which partly closes the feeding orifice ( 24 ), and the servo valve ( 42, 142 ) is pivotingly controlled about its axis (A 1 ) so as to regulate the feeding flow rate by modifying the closure area of the wall ( 44, 144 ).

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a device for filling receptacles with a liquid. 
     The invention relates more particularly to a device for filling receptacles with a liquid, comprising a generally tubular body that comprises, in an upper section, a liquid feed chamber which is provided, at its bottom axial end, with a nozzle for the flow of the liquid from the feed chamber to a receptacle, of the type in which a liquid feed duct leads into the feed chamber through a feed orifice, and of the type comprising a stopper that is controlled in sliding axially inside the tubular body between an axial open position and an axial closed position, and which comprises an annular bearing surface which rests axially against a matching seat arranged between the feed chamber and the nozzle, in the closed position. 
     This type of device is used mainly in automatic installations for filling polyethylene terephthalate (PET) bottles. 
     2. Description of the Related Art 
     When a receptacle is filled with a liquid, the user is usually faced with the problem of the formation of a froth on the surface of the liquid. Most of the liquids have a lesser or greater propensity to froth when they are inserted into a receptacle. For a given liquid, the size of the frothing phenomenon depends on the filling rate and the shape of the receptacle. For one and the same receptacle, the higher the rate, the greater the formation of froth. 
     When the foam clears, the receptacle contains less liquid than it should, hence a metering inaccuracy. 
     In addition, the volume left free in the receptacle, after the froth has cleared, contains air, therefore oxygen, which may adversely affect the correct conservation of the liquid: the smaller the free volume, the better conservation is. 
     The formation of froth is therefore a constraint which leads to reducing the filling rate, which is a disadvantage in terms of filling speed, or which leads to causing an overflow of the liquid, which is not a satisfactory solution. 
     To solve these problems, document WO-A-00/27743 proposes a filling device capable of operating with two discrete filling rates. The filling device comprises a stopper comprising two distinct open positions corresponding to two filling rates, which makes it possible to reduce the value of the flow at the end of the filling operation in order to reduce the formation of froth. 
     Although this filling device has given satisfaction, it does not make it possible to minimize the free volume in the receptacle in all configurations, for example for receptacles of different shapes. 
     SUMMARY OF THE INVENTION 
     The invention proposes to solve these problems by means of a filling device comprising means for varying the filling rate in a continuous manner. 
     Accordingly, the invention proposes a filling device of the type described above, characterized in that it comprises a cylindrical valve coaxial with the stopper that is arranged in the top section of the tubular body, in that the cylindrical valve comprises a peripheral stopping wall that is capable of partially closing off the feed orifice, when the stopper occupies its open position, the area of closure of the peripheral wall being a function of the angular position of the cylindrical valve, and in that the cylindrical valve is controlled so as to pivot about its axis so as to regulate the value of the feed flow by modifying the area of closure of the peripheral wall. 
     According to other features of the invention:
         the cylindrical valve comprises a tubular section coaxial with the stopper and with an external diameter substantially equal to the internal diameter of the top section of the tubular body, that is closed toward the top and that is open toward the bottom, the feed orifice opens radially into the top section of the tubular body, the peripheral wall of closure consists of the outer axial wall of the tubular section, and the tubular section comprises a radial opening that is positioned generally facing the feed orifice when the stopper occupies its open position, so as to have the feed duct communicate with the feed chamber through the central duct of the tubular section;   the cylindrical valve comprises a tubular section coaxial with the stopper comprising a closure finger with an external diameter that is substantially equal to the internal diameter of the top section of the tubular body, in that the peripheral wall of closure consists of the outer axial wall of the finger, and in that the feed duct is closed when, the stopper occupying its closed position, the finger of the tubular section is positioned angularly generally facing the feed orifice in order to interrupt the communication with the feed chamber;   the cylindrical valve is connected in axial movement with the stopper;   the cylindrical valve is connected in pivoting with the stopper so that the angular pivoting of the cylindrical valve is controlled by the angular pivoting of the stopper;   the cylindrical valve comprises a plunger core which extends axially downward, from the bearing surface, into the nozzle;   the bottom end section of the nozzle comprises a concave frustoconical wall whose internal diameter decreases downward, the plunger core comprises, at its bottom axial end, a convex frustoconical surface substantially parallel to the concave frustoconical wall, the bottom axial end of the convex frustoconical surface is substantially radially aligned with the bottom axial end of the concave frustoconical wall when the stopper occupies its closed position, and the diameter of the bottom axial end of the convex frustoconical surface is less than the diameter of the bottom axial end of the concave frustoconical wall so as to arrange an annular space with a radial dimension that is just sufficient to cause a rising of the liquid by capillary action, at the time when the stopper closes;   the bearing surface is arranged on a ring made of elastomer that is fitted to the body of the stopper.       

    
    
     
       BRIEF DESCRIPTION OF THE DRAWING FIGURES 
       Other features and advantages of the invention will appear on reading the following detailed description for the understanding of which reference will be made to the appended drawings in which: 
         FIG. 1  is a view in axial section along the plane  1 - 1  that represents the filling device according to the invention when its stopper occupies a closed axial position and when its cylindrical valve occupies an angular position of partial closure; 
         FIG. 2  is a view similar to that of  FIG. 1  along the sectional plane  2 - 2  which represents the filling device of  FIG. 1  when the stopper occupies an open axial position and when the cylindrical valve occupies an angular position in which its opening is aligned with a liquid feed pipe; 
         FIG. 3  is a view in cross section along the plane  3 - 3  which represents the filling device of  FIG. 1  in the configuration of  FIG. 2 ; 
         FIG. 4  is a view similar to that of  FIG. 3  that represents the filling device of  FIG. 1  when the cylindrical valve occupies a partially closed angular position; 
         FIG. 5  is a view in axial section similar to  FIG. 1  that illustrates a variant embodiment of the cylindrical valve and that represents the filling device according to the invention when its stopper occupies a closed axial position and when its cylindrical valve occupies a fully closed angular position; 
         FIG. 6  is a view in cross section along the plane  6 - 6  that represents the filling device in the configuration of  FIG. 5 ; 
         FIG. 7  is a view in cross section similar to  FIG. 6  which represents the filling device of  FIG. 5  when its cylindrical valve occupies a fully open angular position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the rest of the description, similar or identical elements will be indicated by the same reference numbers. 
       FIGS. 1 to 4  show a device  10  for filling receptacles with a liquid that is made according to the teachings of the invention. 
     The filling device  10  comprises a generally tubular body  12  which in this instance extends along a vertical axis A 1  and which comprises, in a top section  14 , a generally cylindrical bore  16 . 
     In the rest of the description, in a nonlimiting manner, a vertical axial orientation along the axis A 1  of the tubular body  12  will be used. 
     The bore  16  is closed, at its top axial end, by a transverse cap  19  that is attached to the tubular body  12 . 
     The tubular body  12  comprises, at its bottom axial end, a generally tubular section forming a nozzle  20  for the flow of the liquid, from a feed chamber  18  to a receptacle (not shown) provided to be arranged beneath the filling device  10 . 
     A liquid feed duct  22  leads into the feed chamber  18 , in this instance through a radial feed orifice  24  that is pierced in the outer axial wall of the top section  14  of the tubular body  12 . 
     The filling device  10  comprises a stopper  26 , or valve element, which is controlled in axial sliding inside the tubular body  12 . 
     The stopper  26  in this instance has generally a shape of revolution about its axis A 1 . 
     The stopper  26  slides between two extreme axial positions: a top open position, which is represented in  FIG. 2 , and a bottom closed position, which is represented in  FIG. 1 . 
     The stopper  26  comprises an annular bearing surface  28  that is provided to press axially against a matching seat  30 , when the stopper  26  occupies its closed position, so as to hermetically close the annular passageway  32  allowing the liquid to travel toward the nozzle  20 . 
     The seat  30  is arranged in an intermediate section  34  of the tubular body  12  that is situated between the feed chamber  18  and the nozzle  20 . 
     The seat  30  has a generally concave frustoconical shape, with an internal diameter that decreases downward. 
     The bearing surface  28  is in this instance made in a ring  36  made of elastomer which is fitted to the body  38  of the stopper  26 . The ring  36  forms an outer flange which presses against the seat  30 , by elastic deformation, in the closed position, which seals the closure. 
     The body  38  of the stopper  26  is in this instance attached to the bottom axial end of a control rod  40  which extends axially upward, through the cap  19 . 
     The rod  40  is connected to control means (not shown), for example a pneumatic cylinder which is capable of causing the rod  40  to slide upward and downward. 
     According to the teachings of the invention, the filling device  10  comprises a cylindrical valve  42 , coaxial with the stopper  26 , which is arranged in the feed chamber  18 . 
     The cylindrical valve  42  comprises a peripheral wall ( 44 ) of closure which is capable of partially closing the feed orifice  24 , when the stopper  26  occupies its open position. The area of closure of the wall  44  is a function of the angular position of the cylindrical valve  42 . 
     The cylindrical valve  42  is controlled in pivoting about it axis A 1  so as to regulate the value of the feed rate by modifying the area of closure of the peripheral wall  44 . 
     According to the embodiment represented in  FIGS. 1 to 4 , the cylindrical valve  42  comprises a tubular section  46  coaxial with the stopper  26  and with an external diameter that is substantially equal to the internal diameter of the feed chamber  18 . 
     The tubular section  46  of the cylindrical valve  42  is closed, at its top axial end, by a transverse wall  48  and it is open toward the bottom, that is to say toward the nozzle  20 . 
     The tubular section  46  of the cylindrical valve  42  comprises a radial opening  50  which is positioned generally facing the feed orifice  24 , when the stopper  26  occupies its open position, so as to have the feed duct  22  communicate with the feed chamber  18  through the central duct  52  of the tubular section  46 . 
     Advantageously, the radial opening  50  has a circular section of passage and its diameter is substantially equal to the diameter of the feed orifice  24 . 
     The peripheral wall  44  of closure consists of the outer axial wall of the tubular section  46  around the opening  50 . 
     Advantageously, the cylindrical valve  42  is attached to the control rod  40 , so that it is connected to the stopper  26 , both in axial movement and in pivoting. 
     Therefore, the stopper  26  and the cylindrical valve  42  may be controlled simultaneously in the appropriate axial and angular position. 
     Note that the cylindrical valve  42  slides axially in the bore  16  with the stopper  26 . 
     According to an advantageous embodiment, the top section of the nozzle  20  comprises a concave cylindrical wall  54  and the bottom end section of the nozzle  20  comprises a concave frustoconical wall  56  whose internal diameter decreases downward. 
     The stopper  26  comprises a plunger core  58  which extends axially downward, from the bearing surface  28  inside the nozzle  20 . 
     The plunger core  58  comprises, at its bottom axial end, a convex frustoconical surface  60  substantially parallel to the concave frustoconical wall  56  of the nozzle  20 . 
     The axial length of the convex frustoconical surface  60  is less than the axial length of the concave frustoconical wall  56 . 
     The bottom axial end  62  of the convex frustoconical surface  60  is substantially radially aligned with the bottom axial end  64  of the concave frustoconical wall  56 , when the stopper  26  occupies its closed position. 
     The diameter of the bottom axial end  62  of the convex frustoconical surface  60  is less than the diameter of the bottom axial end  64  of the concave frustoconical wall  56 , which arranges an annular space  66  with a radial dimension that is just sufficient to cause a rising of the liquid by capillary action, at the time when the stopper  26  closes. 
     Advantageously, the plunger core  58  comprises a convex frustoconical intermediate section  68  with a diameter that increases downward. 
     Now the operation of the filling device  10  according to the invention is described. 
     Before filling, the stopper  26  occupies its closed position ( FIG. 1 ). 
     When a bottle is placed axially beneath the nozzle  20 , the stopper  26  is controlled to the open position ( FIG. 2 ) by means of the rod  40 , so that the liquid situated above the seat  30 , in the feed chamber  18  and in the feed duct  22 , descends into the nozzle  20 . 
     The liquid flows along and around the core  58 . 
     Note that the core  58  guides the flow of liquid so as to produce a flow of the laminar type, which minimizes the production of froth and accelerates the filling of the bottle. 
     Advantageously, at the beginning of filling, the cylindrical valve  42  is controlled into the fully open angular position, which is represented in  FIGS. 2 and 3 , that is to say that the opening  50  is aligned with the feed orifice  24 . 
     Toward the end of filling, the cylindrical valve  42  is controlled to pivot about its axis A 1 , to a final angular position as represented in  FIG. 4 . 
     During the pivoting of the cylindrical valve  42 , the area of the section of passage of the liquid between the feed duct  22  and the opening  50  reduces progressively, because the peripheral wall  44  of the cylindrical valve  42  increasingly closes off the feed orifice  24 , so that the liquid filling rate diminishes progressively. 
     Note that the substantially continuous diminution of the filling rate makes it possible to minimize turbulence in the liquid flow, which minimizes the production of froth. 
     At the end of filling, the stopper  26  is controlled to the closed position, which stops the flow of the liquid to the nozzle  20  almost instantaneously. 
     Thanks to the structure of the bottom end section of the core  58  and to the structure of the bottom end section of the nozzle  20 , filling stops completely since the liquid that reaches the bottom end of the nozzle  20  tends to rise by capillary action in the annular space  66 . 
     In comparison with the embodiment represented in  FIGS. 1 to 4 , a variant embodiment of the cylindrical valve  142  that the filling device  10  according to the invention comprises is described below. 
     Advantageously, the cylindrical valve  142  is coaxial with the stopper  26  and it is arranged in the feed chamber  18 . 
     Therefore, the cylindrical valve  142  comprises a peripheral wall  144  of closure which is capable of partially closing the feed orifice  24 , when the stopper  26  occupies its open position. The area of closure of the wall  144  is a function of the angular position of the cylindrical valve  142 . 
     The cylindrical valve  142  is controlled to pivot about its axis A 1  in order to regulate the value of the feed rate by modifying the area of closure of the peripheral wall  144 . 
     According to the variant embodiment represented in  FIGS. 5 to 7 , the cylindrical valve  142  comprises a tubular section  146  from which a closure finger  143  extends radially. 
     The tubular section  146  is coaxial with the stopper  26  and it is preferably centered on the axis A 1  of the stopper  26 . 
     The tubular section  146  comprises an outer cylindrical surface  145  determining its external diameter which is less than the internal diameter of the feed chamber  18  that is determined with the cylindrical bore  16  of the top section  14  of the body  12 . 
     The top portion of the annular-shaped feed chamber  18  is delimited radially by the outer cylindrical surface  145  and the bore  16  and is open downward, that is to say toward the nozzle  20 . 
     The peripheral wall  144  of closure consists of the outer axial face of the closing finger  143  extending vertically and whose external diameter is substantially equal to the internal diameter of the feed chamber  18 . 
     As can be seen in  FIGS. 5 and 6 , the cylindrical valve  142  is in the fully closed angular position which corresponds to a position of the cylindrical valve  142  in which the closure finger  143  is angularly positioned generally facing the feed orifice  24  of the feed duct  22 . 
     The feed orifice  24  is then closed by the peripheral wall  144  of the finger  143  whose width is at least equal to the diameter of the feed orifice  24 . 
     When the stopper  26  occupies its open position, the angular movement of the tubular section  146  of the cylindrical valve  142  and of the finger  143  causes the feed orifice  24  to open fully or partially, so as to have the feed duct  22  communicate with the top portion of the feed chamber  18  surrounding the section  146 . 
     Advantageously, the cylindrical valve  142  is attached to the control rod  40 , so that it is connected to the stopper  26 , both in axial movement and in pivoting and that it slides axially in the bore  16  with the stopper  26 . 
     Therefore, the stopper  26  and the cylindrical valve  142  may be controlled simultaneously to the appropriate axial and angular position. 
     The operation of the filling device  10  with the cylindrical valve  142  is consequently similar to that described above. 
     Before filling, the stopper  26  occupies its closed position shown in  FIG. 5 . 
     When a bottle is placed axially beneath the nozzle  20 , the stopper  26  is controlled to the open position (not shown, which is similar to that shown in  FIG. 2 ) by means of the rod  40 , so that the liquid situated above the seat  30 , in the feed chamber  18  and in the feed duct  22 , descends into the nozzle  20 . 
     The liquid flows along and around the core  58  which guides the stream of liquid so as to produce a flow of the laminar type in order to minimize the production of froth and accelerate the filling of the bottle. 
     Advantageously, at the beginning of filling, the cylindrical valve  142  is controlled to the fully open angular position, which is represented in  FIG. 7 , that is to say the position in which the finger  143  is offset angularly so that, the closing wall  144  being opposite the bore  16 , the feed orifice  24  communicates fully with the chamber  18 . 
     Toward the end of filling, the cylindrical valve  142  is controlled to pivot about its axis A 1  so as to return to the previous totally closed position which, represented in  FIG. 6 , is the final angular position. 
     While the cylindrical valve  142  pivots, the area of the section of passage of the liquid between the feed duct  22  and the chamber  18  reduces progressively, because the peripheral wall  144  of the finger  143  of the cylindrical valve  42  increasingly closes the feed orifice  24  so that the liquid filling rate reduces progressively. 
     At the end of filling, the stopper  26  is controlled to the closed position, which stops the flow of liquid toward the nozzle  20  almost instantaneously.