Machine for filling containers with liquids, provided with a filling level correction system

A machine for filling containers with liquids, provided with a filling level correction system, which comprises:

• a support structure;
• a rotating carousel rotatably mounted on said support structure, and provided with a tank for containing a liquid to be bottled in containers;
• a plurality of valve groups mounted peripherally on said rotating carousel each responsible for filling a container;
• and
• a logic control unit suitable to automatically manage the operation of said filling machine,
• wherein each valve group comprises:
• a supply duct hydraulically connected to said tank for the inflow of said liquid from said tank into said containers to be filled;
• a shutter placed to intercept said supply duct to adjust the inflow of said liquid into said containers;
• a return air tube which is mounted coaxially inside said supply duct and is provided with an open lower end, susceptible to be inserted in said container, and a upper end, which is opposite said lower end and can be connected hydraulically to said tank or to a separate drainage circuit, said return air tube being movable axially between at least one lowered position and a raised position, regardless of said shutter;
• and
• a duct which can be fluidically connected to a pressurised gas circuit to introduce gas into the container at the end of filling and thus expel through said tube the excess liquid that may have filled the container beyond the height at which the lower end of the return air tube is placed, corresponding to said lowered position, thereby performing a correction of the filling level,
• wherein each valve group comprises:
• means for guiding the axial movement of the return air tube between a lower end stop and an upper end stop, wherein said at least one lowered position is between said two end stops;
• elastic mechanical means suitable to exercise constantly an axial thrust action on said return air tube towards said raised position;
• means for reversibly blocking the return air tube in any axial position between said lower end stop and said upper end stop;
• and
• a cam follower rigidly connected to said return air tube;
• and wherein said filling machine comprises a cam which is placed peripherally to said rotating carousel at a first angular position α1 with respect, to an entry station to be cyclically engaged by the cam follower of each valve group, wherein said cam is profiled so as to impose on each tube by means of the relative cam follower a predetermined axial displacement H from a position corresponding to the upper end stop towards said lower end stop, overcoming the opposite thrust of said elastic mechanical means and placing the tube in a lowered position with respect to the position corresponding to the upper end stop, said cam having an operating angle of working Δ which covers only a portion of the circumferential extension of the rotating carousel, and wherein said filling machine comprises means for moving the cam in height in relation to said support structure in order to adjust the height corresponding to said lowered portion,
• and wherein the logic control unit is operatively connected to the means for moving the cam in height to adjust automatically the height corresponding to said lowered position, as well as to the reversible blocking means of each return air tube so as to command the blocking and unblocking action, wherein said logic control unit is programmed:
• to command the blocking of the reversible blocking means of each individual return air tube when the individual tube is located within the operating angle of working Δ of the cam to keep the return air tube in the lowered position which it was brought to by said cam itself, opposing the action of the elastic mechanical means, and
• to command the unblocking of the reversible blocking means of each individual air return tube at a second angular position α2 chosen as a function of the filling operating cycle to be performed on the containers, so as to allow the return of the individual tube to the raised position under the action of the relative elastic mechanical means, said second angular position α2 being placed downstream of the first angular position α1 and upstream of an exit station 6.