Method for forming and filling a container using a liquid having a swirl flow

Abstract

A method and forming station for simultaneously forming and filling a container by injecting a pressurized liquid into a preform. The forming station includes a mold having a molding cavity and an injection nozzle coupled to a pressurized liquid source. The injection nozzle includes a nozzle body and an outlet, the nozzle body defining an injection axis and the outlet being arranged to inject a pressurized liquid from the pressurized liquid source along the injection axis into the preform. The injection nozzle further includes a swirl imparting element arranged to impart a swirl flow to the pressurized liquid about the injection axis, through the outlet and into the preform whereby the preform is formed into the container filled with the pressurized liquid.

I/We claim: 
     
         1 . A method for simultaneously forming and filling a container by injecting a pressurized liquid in a preform extending along a preform axis, using a forming station having an injection nozzle and a source of pressurized liquid arranged to inject a pressurized liquid through an outlet of the injection nozzle, the method comprising the steps of:
 placing the preform in a mold having a molding cavity defining the shape of the container to be produced;   injecting the pressurized liquid into the preform through an outlet of an injection nozzle, the pressurized liquid flowing from a pressurized liquid source to the outlet along an injection flow, the liquid expanding the preform and urging the wall of the preform against the wall of the molding cavity such that the preform is formed into a container and the container is filled with the liquid; and   imparting a swirl flow on the pressurized liquid and applying a centrifugal force on the wall of the preform during forming and filling of the preform, thereby promoting a radial expansion of the.   
     
     
         2 . The method according to  claim 1 , further comprising the step of axially expanding the preform along the preform axis. 
     
     
         3 . The method according to  claim 1 , wherein the pressurized liquid swirls around the preform axis according to a swirling slope. 
     
     
         4 . The method according to  claim 3 , wherein the swirling slope forms an angle of between 40° and 60° with the preform axis. 
     
     
         5 . The method according to  claim 1 , wherein the swirl flow is imparted such that the pressurized liquid is swirling during injection into the preform. 
     
     
         6 . The method according to  claim 1 , wherein radial expansion of the preform occurs substantially simultaneously along a major part of the height of the preform, measured along the preform axis. 
     
     
         7 . A forming station for simultaneously forming and filling a container by injecting a pressurized liquid into a preform, the forming station comprising:
 a pressurized liquid source;   a mold having a molding cavity; and   an injection nozzle having an nozzle body and an outlet, the nozzle body defining an injection axis and the outlet being arranged to inject a pressurized liquid from the pressurized liquid source along the injection axis into the preform, the injection nozzle further including a swirl imparting element arranged to impart a swirl flow to the pressurized liquid about the injection axis, through the outlet and into the preform whereby the preform is formed into the container filled with the pressurized liquid.   
     
     
         8 . The forming station according to  claim 7 , wherein the swirl imparting element is located adjacent to the outlet. 
     
     
         9 . The forming station according to  claim 7 , wherein the swirl imparting element includes a plurality of fins extending across at least a part of an injection flowpath defined in the injection nozzle. 
     
     
         10 . The forming station according to  claim 9 , wherein the fins have a spiral shape and extend along the injection axis. 
     
     
         11 . The forming station according to  claim 9 , wherein each fin includes an upstream end and a downstream end, the tangent of the upstream end being substantially parallel to the injection axis, the fins being arcuate between the upstream end and the downstream end. 
     
     
         12 . The forming station according to  claim 9 , wherein two successive fins form an angle with the injection axis within the range of 24° to 72°. 
     
     
         13 . The forming station according to  claim 9 , wherein the fins extend one of from or toward the nozzle body. 
     
     
         14 . The forming station according to  claim 16 , wherein a cross-section in a radial plane of each fin extends only partially across the injection flowpath. 
     
     
         15 . The forming station according to  claim 9 , wherein the injection nozzle includes a closing valve and a valve seat, the closing valve being movable between a closed position preventing the pressurized liquid from flowing through the outlet and an open position allowing pressurized liquid to flow through the outlet. 
     
     
         16 . The forming station according to  claim 15 , wherein the closing valve includes a control rod having a sealing part placed in liquid tight contact with the valve seat in the closed position. 
     
     
         17 . The forming station according to  claim 16 , wherein the fins extend from the control rod. 
     
     
         18 . The forming station according to  claim 16 , wherein the cross-section in a radial plane of each fin extends over only a part of the distance separating the control rod and the nozzle body. 
     
     
         19 . The forming station according to  claim 16 , wherein the injection nozzle includes a nozzle chamber extending upstream of the outlet, the control rod extending and being movable inside the nozzle chamber. 
     
     
         20 . The forming station according to  claim 16 , wherein the fins are positioned at least one of upstream or downstream of the sealing part of the control rod.