US 4,731,250 AGranted

Method and an arrangement for the continuous heat treatment and packaging of a liquid product

AssigneeTetra Pak International AB

InventorSven O. S. Stark

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Abstract

The invention relates to a method and an arrangement for the continuous heat treatment and packaging of a liquid product with the object of sterilizing the product, the product being heated for a short time together with, and surrounded by, the packing material wherein it is to be enclosed. The product is introduced into a tube of flexible material whereupon the tube containing the product is introduced between two parallel metal bands, movably synchronously in their longitudinal direction, the tube being received and compressed between the bands so that the tube is transported with the bands at the same time as the cross-sectional area of the tube is reduced and the product is made to flow forward through the compressed tube in a gaplike space. Heat is transmitted to the product with the help of the metal bands while the product present between the metal bands is kept under pressure. After the heating required for sterilization, the product is cooled and while it is still in the tube, is made to emerge and be freed from the metal bands, whereupon the tube and the product are divided into individual packing units through repeated transverse sealing of the tube.

Claims14

Dependent claims

A method for continuous heat treatment and packaging of a liquid product, having a predetermined boiling point contained in a packing material for reducing micro-organism content of the product, the product and packing material being heated and subsequently cooled, comprising the steps of:

(a) moving a flexible tube of the packing material;
(b) introducing the product into the flexible tube;
(c) passing the tube and the product contained therein into gap formed between two opposed, substantially parallel bands driven synchronously at a first substantially constant speed in a longitudinal direction;
(d) exposing the product to a pressure zone wherein the product and tube are heated and cooled, said pressure zone being maintained by compressing the tube and limiting expansion thereof between the bands by moving the bands toward one another between opposed, spaced apart supports sufficient for transporting the tube with the bands at said first speed, and simutlaneously reducing the cross-sectional area of the tube to a space of substantially uniform gap width, and said pressure zone further being maintained by pumping said product through said gap at a second substantailly constant speed, greater than said first speed, sufficient for increasing the pressure of said product so as to increase said predetermined boiling point;
(e) heating the moving tube and the product contained in the tube for a predetermined period in a heating zone within said pressure zone to a temperature sufficient for sterilizing said product below said increased boiling point;
(f) cooling the moving heated tube and the product contained in the tube in a cooling zone within the pressure zone;
(g) relieving said increased pressure in said moving cooled tube in a throttling zone wherein said uniform gap width is reduced by guiding said belts between portions of said opposed supports spaced closer together than in said pressure zone;
and
(h) subsequently relieving compression of said moving tube and dividing said cooled tube and product into individual sterilized packaging units through repeated transverse sealing of the tube.

6 more elements

A method for continuous heat treatment and packaging of a liquid product, having a predetermined boiling point at atmospheric pressure, contained in a packing material for reducing micro-organism content of the product, comprising the steps of:

(a) moving a flexible tube of the packing material;
(b) introducing the product into the flexible tube, said product being at about atmospheric pressure;
(c) passing the tube and the product contained therein into a gap formed between two opposed, substantially parallel bands driven synchronously at a first substantially constant speed in a longitudinal direction;
(d) exposing the product to a pressure zone where in the product and tube are heated and cooled, said pressure zone being maintained by compressing the tube and limiting expansion thereof between the bands by moving the bands towards one another between opposed, spaced apart supporting elements sufficient for transporting the tube with the bands at said first speed, and simultaneously reducing the cross-sectional area of the tube to a space of substantially uniform gap width;
(e) pumping said product through said gap at a second substantially constant speed, greater than said first speed, sufficient for increasing the pressure of said product from about 2.6 to about 3.0 times atmospheric pressure so as to increase said predetermined boiling point, said pumping being provided by a pair of opposed pressure rollers simultaneously engaging and rolling along said bands at said second speed of from about 5 times to about 20 times said first speed;
(f) heating the moving tube and the product contained in the tube for a predetermined period in a heating zone within said pressure zone to a temperature sufficient for sterilizing said product below said increased boiling point;
(g) cooling the moving heated tube and the product contained in the tube in a cooling zone within the pressure zone;
(h) relieving said increased pressure in said moving cooled tube in a throttling zone wherein said uniform gap width is reduced by guiding said belts between portions of said opposed supporting elements spaced closer together than in said pressure zone;
and
(i) subsequently relieving compression of said moving tube and dividing said cooled tube and product into individual sterilized packaging units through repeated transverse sealing of the tube.

7 more elements

Dependencies are inferred from the claim text.