Encapsulation of Liquids

Abstract

A liquid filling apparatus for filling capsules formed by joining two films carried on cylindrical surfaces of respective drums that are arranged in parallel to define a nip comprises two members ( 150,152 ) having an arcuate tapering cross-section so as to be positionable in such a nip defined by two such drums having a predetermined diameter. Each of the two members has opposed arcuate surfaces that, in use, face the cylindrical surfaces of the respective drums. The arcuate surfaces are provided with apertures through which, in use, a pressurised gas is emitted to provide a gas barrier to prevent a filling liquid supplied into the nip between said members from escaping past the arcuate surfaces.

1 . A liquid filling apparatus for filling capsules formed by joining two films carried on cylindrical surfaces of respective drums that are arranged in parallel to define a nip therebetween, said apparatus comprising two members having an arcuate tapering cross-section so as to be positionable in a said nip defined by two said drums having a predetermined diameter, each said member having opposed arcuate surfaces that, in use, face the cylindrical surfaces of the respective drums and said arcuate surfaces being provided with apertures through which, in use, a pressurized gas is emitted to provide a gas barrier to prevent a filling liquid supplied into the nip between said members from escaping past said arcuate surfaces. 
   
   
       2 . Apparatus as claimed in  claim 1 , wherein said arcuate surfaces of said members are each provided with a plurality of said apertures arranged to define at least one line of apertures. 
   
   
       3 . Apparatus as claimed in  claim 1 , wherein said arcuate surfaces of said members are provided with at least one recess extending in a lengthways direction of the surface, the respective said apertures being provided in the or at least one said recess of the arcuate surface. 
   
   
       4 . Apparatus as claimed in  claim 1 , wherein each of said arcuate surfaces has a lengthways extending relieved portion for passage of an edge portion of the respective said film therebeneath, said apertures being provided in the respective said relieved portions. 
   
   
       5 . Apparatus as claimed in  claim 1 , wherein each said member defines internal passageways for communicating pressurized gas to the respective said apertures. 
   
   
       6 . Apparatus as claimed in  claim 1 , wherein each said member is provided with bearings that, in use, seat on said cylindrical surfaces of the drums to provide a predetermined clearance between said arcuate surfaces and cylindrical surfaces. 
   
   
       7 . Apparatus as claimed in  claim 6 , wherein said bearings comprise rollers mounted on side surfaces of said members that extend between said opposed arcuate surfaces. 
   
   
       8 . Apparatus as claimed in  claim 1 , wherein at least one of said two members is provided with an overflow passageway for the overflow of said filling liquid supplied into said nip between said members. 
   
   
       9 . Apparatus as claimed in  claim 1 , wherein at least one of said two members is provided with at least one aperture through which, in use, an inert gas can be emitted to provide a gas blanket over the filling liquid in said nip between said members. 
   
   
       10 . Apparatus as claimed in  claim 1 ,
 further comprising a support for said two members and at least one biasing element for biasing the two members such that, in use, the members are pressed downwards into said nip.   
   
   
       11 . Apparatus as claimed in  claim 10 , wherein said at least one biasing element comprises respective spring elements bearing against said two members. 
   
   
       12 . Apparatus as claimed in  claim 10 , wherein said support supports a device through which, in use, filling liquid is delivered into said nip. 
   
   
       13 . Apparatus as claimed in  claim 1 , wherein said two members are connected by a transverse member having opposed arcuate surface portions arranged to provide a predetermined clearance with said opposed cylindrical surfaces of the drums when, in use, said members are positioned in said nip. 
   
   
       14 . Apparatus as claimed in  claim 13 , wherein said transverse member defines an elongate aperture through which, in use, filling liquid is delivered into said nip. 
   
   
       15 . Apparatus as claimed in  claim 14 , wherein said elongate aperture substantially extends from one of said members to the other of said members. 
   
   
       16 . A liquid filling apparatus for filling capsules formed by joining two films carried on cylindrical surfaces of respective drums in a nip defined by said drums, said liquid filling apparatus comprising two wedge members positionable in a said nip defined between two said drums, in use, said wedge members being positioned in opposed spaced apart relationship to define a filling space therebetween, and means for providing a pressurized gas barrier for preventing the escape of filling liquid from said filling space past respective faces of said wedge members that, in use, face the said cylindrical surfaces of said drums. 
   
   
       17 . Apparatus as claimed in  claim 16 , wherein said means for providing a gas barrier comprises respective openings provided in said faces of said wedge members. 
   
   
       18 . Apparatus as claimed in  claim 16 , wherein said wedge members are provided with bearing means for bearing on the cylindrical surface of at least one said drum. 
   
   
       19 . Apparatus as claimed in  claim 16 , further comprising biasing means for, in use, biasing the wedge members downwardly into said nip. 
   
   
       20 . Apparatus as claimed in  claim 16 ,
 further comprising means for emitting a pressurized gas to form a gas blanket over a filling liquid in said filling space.   
   
   
       21 . Apparatus for forming liquid filled capsules, said apparatus comprising:
 a first rotatable cylinder and a second rotatable cylinder, at least one of said cylinders defining an array of cavities and each having an axis of rotation, said cylinders being arranged in parallel spaced apart relation to define a nip extending generally parallel to said axes of rotation;   a first blocking member and a second blocking member positioned in said nip in opposed spaced apart relation so as to define a filling space therebetween, each said blocking member having a first arcuate surface facing said first cylinder and a second arcuate surface facing said second cylinder and each said arcuate surface having a plurality of openings defined therein;   a device for supplying filling liquid into said filling space; and   a pressurized gas supply connected with said openings for supplying pressurized gas to said openings to provide respective gas barriers for preventing the escape of filling liquid from said filling space past said arcuate surfaces.   
   
   
       22 . A method of liquid filling capsules formed by joining two films carried on cylindrical surfaces of respective drums in a nip defined between the drums, said method comprising providing two wedge members in said nip spaced apart so as to define a filling space therebetween, delivering a filling liquid into said filing space such that the capsules are substantially flooded when they are formed and providing pressurized gas barriers to prevent escape of the filling liquid from said filling space past said wedge members. 
   
   
       23 . A method as claimed in  claim 22 , wherein said gas barriers are provided by emitting gas from apertures defined by said wedge members. 
   
   
       24 . A method as claimed in  claim 22 , further comprising providing a pressurized gas blanket over the filling liquid in said filling space. 
   
   
       25 . A method as claimed in  claim 22 , comprising providing a predetermined head of filling liquid in said filling space by providing respective clearances of predetermined height and radial extent between respective arcuate surface extending between said wedge members parallel to said cylindrical surfaces and the respective films carried on said cylindrical surfaces and substantially filling said filling space with filling liquid such that said filling liquid reaches an overflow level above said arcuate surface portions. 
   
   
       26 . A method as claimed in  claim 22 , wherein each said film has longitudinally extending edges and said wedge members are positioned such that the gas barriers are directed at said films inwardly of said edges.