Method and installation for packaging a liquid product in a package

Abstract

To package liquids in thin-walled packages while at the same time conferring good mechanical strength upon these packages, an inert gas such as nitrogen and/or carbon dioxide, in the gaseous state is or are introduced into the liquid by means of an injector ( 22 ), the liquid becoming saturated or supersaturated with which gas(es); the product obtained is stored in a reservoir ( 14 ) at a constant level above which an overhead of the said gas is created at a raised pressure which is constant by virtue of regulating means ( 3 ). On demand, this product is transferred, by tapping means ( 4 ), to packages which are partially filled with product the surface of which is surmounted with an overhead of the said gas at a raised pressure after the package has been sealed. Use: packaging of liquids, particularly food liquids.

1 . Method for packaging liquid product in at least one package, characterized in that an inert gas such as nitrogen and/or carbon dioxide, in the gaseous state, is or are mixed with a liquid so as to form a product consisting of the liquid saturated or supersaturated with gas; this product is stored in a buffer reservoir ( 14 ) which is partially filled with product up to a predetermined level; this level is kept approximately constant and, above this level, an overhead of the said gas in the gaseous state, due to the saturation or the supersaturation, at a predetermined approximately constant raised pressure; the said product is transferred on demand from the buffer reservoir to the package, open to atmospheric pressure, keeping the said predetermined level and the said predetermined raised pressure in the buffer reservoir so as to partially fill the package with the said product with an overhead of the said gas at a pressure the value of which is approximately equal to that of the overhead in the buffer reservoir ( 14 ), and the package is sealed.  
     
     
         2 . Method according to  claim 1 , characterized in that when, in the buffer reservoir ( 14 ), the raised pressure of the overhead of the said gas reaches the predetermined raised pressure, the excess gas is discharged.  
     
     
         3 . Method according to either one of claims  1  and  2 , characterized in that, in order to mix the inert gas and/or the carbon dioxide in the gaseous state into the liquid, this gas is injected into the liquid.  
     
     
         4 . Method according to any one of  claims 1  to  3 , characterized in that the raised pressure in the overhead of the buffer reservoir ( 14 ) is set to a value lying in the range of 10 mbar to 3 bar.  
     
     
         5 . Method according to  claim 4 , characterized in that the raised pressure is set to a value of about 50 mbar.  
     
     
         6 . Plant for packaging liquid product in at least one package, characterized in that it comprises a first circuit ( 1 ) in at least part of which a liquid is circulated, a second circuit ( 2 ) in at least part of which an inert gas such as nitrogen and/or carbon dioxide, is circulated under pressure in the gaseous state and which at outlet comprises an injector ( 22 ) opening into an injection zone of the first circuit so as to form a product consisting of the liquid saturated or supersaturated with gas, the first circuit ( 1 ) comprising a buffer reservoir into which the said product is introduced, means for keeping a predetermined level of liquid in this buffer reservoir, control and regulating means ( 3 ) for maintaining a predetermined approximately constant raised pressure due to the saturation or supersaturation in the buffer reservoir, and means ( 4 ) for tapping from the reservoir in order to transfer the said product from it into the package with an overhead at a pressure the value of which is approximately equal to that of the overhead in the buffer reservoir ( 14 ).  
     
     
         7 . Plant according to  claim 6 , characterized in that the first circuit ( 1 ) comprises a transfer pump ( 11 ), the inlet of which is supplied with liquid to be saturated or supersaturated with gas, for circulating this liquid, and a filling line ( 12 ), the upstream end of which is connected to the outlet of the pump, an injector belonging to the second circuit ( 2 ) opening into the line ( 2 ) downstream of the pump ( 11 ) for injecting the pressurized gas in the gaseous state thereinto.  
     
     
         8 . Plant according to either one of claims  6  and  7 , characterized in that the control and regulating means ( 3 ) comprise a regulator ( 31 ), a pressure transducer ( 32 ) measuring the pressure of the gas in the overhead of the reservoir ( 14 ) and a level detector ( 33 ) detecting the level of the said product in the reservoir ( 14 ), these being connected to the regulator, and a regulator exhaust valve ( 34 ), controlled by the regulator ( 31 ) and connected to the overhead in the reservoir ( 14 ) so as to discharge excess gas therefrom on the command of the regulator.  
     
     
         9 . Plant according to any one of  claims 6  to  8 , characterized in that the second circuit ( 2 ) comprises injection equipment ( 21 ) supplying the injector ( 22 ), and the control and regulating means ( 3 ) comprise a regulator ( 31 ) electrically or pneumatically connected to the injection equipment in order to transmit to it a signal that regulates the injection.  
     
     
         10 . Plant according to any one of  claims 6  to  9 , characterized in that the raised pressure kept approximately constant lies within the range from 10 mbar to 3 bar.  
     
     
         11 . Plant according to  claim 10 , characterized in that the raised pressure has a value of about 50 mbar.  
     
     
         12 . Plant according to any one of  claims 6  to  11 , characterized in that the control and regulating means ( 3 ) comprise a calibrated safety valve ( 35 ) connected to the top of the reservoir ( 14 ).