Method of pasteurizing, monitoring PU-uptake, controlling PU-up-take and apparatus for pasteurizing

Abstract

A continuous flow pasteurization apparatus for a liquid product includes a pasteurization area divided into plural pasteurization zones, each with a connection for heating and/or cooling the product, so that if production stops, it is possible to hold the temperature below the pasteurizing temperature. Upon restarting, the product is reheated to a temperature close to the pasteurizing temperature. The apparatus provides for the control and monitoring of pasteurization units (PU's).

What is claimed is:  
     
         1 . A method of pasteurizing a flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, the method comprising the steps of: 
 providing one or more heat exchangers for exchanging heat between the flow of liquid product and heating and/or cooling means, respectively; and    maintaining the flow of liquid product inside said one or more heat exchangers during a period of time and at temperatures sufficient for the uptake of Pasteurizing Units (PU's), the majority of a desired predetermined amount of PU's being taken up by the flow of liquid product during said period of time.    
     
     
         2 . The method according to  claim 1 , wherein said majority is selected from the group of values consisting of at least 51%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% and at least 95% of said desired amount of PU's.  
     
     
         3 . A method of pasteurizing a flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, the method comprising the steps of: 
 providing a pasteurizing heat exchanger for exchanging heat between the liquid product and a flow of fluid, preferably water, so as to heat or cool the liquid product during the passage thereof through the pasteurizing heat exchanger;    introducing the flow of liquid product at a product inlet temperature into an inlet of the pasteurizing heat exchanger;    introducing the flow of fluid at a fluid inlet temperature into the pasteurizing heat exchanger;    discharging the flow of liquid product from an outlet of the pasteurizing heat exchanger at a product outlet temperature; and    controlling the rate of flow of the flow of liquid product and/or said product inlet temperature and/or the rate of flow of the flow of fluid and/or said fluid inlet temperature and/or said product outlet temperature such that the flow of liquid product takes up the majority of the Pasteurizing Units (PU's) required for obtaining a desired degree of pasteurization during the passage of said flow of liquid product through the pasteurizing heat exchanger.    
     
     
         4 . The method according to  claim 3 , wherein said majority is selected from the group of values consisting of at least 51%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% and at least 95% of said desired amount of PU's  
     
     
         5 . The method according to  claim 3  and further comprising the steps of: 
 providing one or more additional pasteurizing heat exchangers comprising the features of the pasteurizing heat exchanger according to  claim 3 , all the pasteurizing heat exchangers being arranged in series such that the flow of liquid product is conducted from the outlet of one pasteurizing heat exchanger to the inlet of the succeeding pasteurizing heat exchanger; and  
 controlling the rate of flow of the flow of liquid product through the series of pasteurizing heat exchangers and/or said product inlet temperature of at least the first of the heat exchangers in said series and/or the rate of flow of the flow of fluid through at least one and preferably all the heat exchangers in said series and/or said fluid inlet temperature of the flow of fluid introduced into at least one and preferably all the heat exchangers in said series and/or said product outlet temperature of at least the last of the heat exchangers in said series such that the entire flow of liquid product takes up a majority of the PU's required for obtaining a desired degree of pasteurization during the passage of said liquid product through said series of pasteurizing heat exchangers.  
 
     
     
         6 . The method according to  claim 5 , wherein said majority is selected from the group of values consisting of at least 51%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% and at least 95% of said desired amount of PU's.  
     
     
         7 . The method according to  claim 5 , wherein the length of the path of the flow of liquid product from the outlet of one of the pasteurizing heat exchangers in said series to the inlet of the succeeding pasteurizing heat exchanger in said series is substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of fluid.  
     
     
         8 . The method according to  claim 3 , further comprising the steps of: 
 providing one or more heat recuperating or regenerative heat exchangers for exchanging heat between the unpasteurized liquid product flowing into the pasteurizing heat exchanger and the pasteurized liquid product flowing from the pasteurizing heat exchanger so as to cool the pasteurized liquid product, pre-heat the unpasteurized liquid product to product inlet temperature and recuperate heat energy from the pasteurized liquid product; and    determining the number of PU's taken up by the liquid product when flowing through the one or more regenerative heat exchangers in both directions and when flowing along paths of flow leading to and from the pasteurizing heat exchanger from and to, respectively, the one or more regenerative heat exchangers such that the amount of additional PU's to be taken up by the liquid product in the pasteurizing heat exchanger can be determined.    
     
     
         9 . The method according to claims  3 , comprising the further step of: 
 providing one or more heat recuperating or regenerative heat exchangers for exchanging heat between the unpasteurized liquid product flowing into the pasteurizing heat exchanger and the pasteurized liquid product flowing from the pasteurizing heat exchanger so as to cool the pasteurized liquid product, pre-heat the unpasteurized liquid product to said first temperature and recuperate the heat energy from the pasteurized liquid product;    wherein the length of said paths of flow to and from the pasteurizing heat exchanger from and to, respectively, the one or more regenerative heat exchangers are substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of said fluid.    
     
     
         10 . A method of monitoring the uptake of Pasteurizing Units (PU's) of a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in a pasteurizing apparatus comprising means for exchanging heat between one or more flows of a fluid, preferably water, and the flow of liquid product, said method comprising the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at first points along the paths of flow thereof through the apparatus; and    establishing a mathematical model of the apparatus and, based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid at any or all of said second points.    
     
     
         11 . The method according to  claim 10 , wherein the number of second points is sufficiently large for obtaining a desired accuracy of the monitoring of said uptake of PU's.  
     
     
         12 . The method according to  claim 11 , wherein the number of second points is selected from the group of values consisting of at least 5, at least 25, at least 50, at least 100, at least 150, at least 200, at least 300, at least  400 , at least 500, at least 600, at least 700, at least 800, at least 900, and at least 1,000, the maximum number of said second points being determined by the calculating capacity of a computing means utilized for calculating said number of PU's.  
     
     
         13 . A method of controlling the uptake of Pasteurizing Units (PU's) of a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consummable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in a pasteurizing apparatus comprising means for exchanging heat between one or more flows of a fluid, preferably water, and the flow of liquid product, said method comprising the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at first points along the paths of flow thereof throughout the apparatus;    establishing a mathematical model of the apparatus and, based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid at any of said second points; and    altering the temperature and/or rate of flow of one or more of the flows of fluid and/or the rate of flow of the flow of the liquid product such that any unacceptable difference between the calculated uptake of PU's and a desired uptake of PU's for one or more portions of liquid product at corresponding one or more second points is eliminated before said one or more portions exit the apparatus.    
     
     
         14 . A method of monitoring the operation of a pasteurizing apparatus for pasteurizing a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, said apparatus comprising: 
 one or more heat exchangers for heating and/or cooling the flow of liquid product;    sources of flows of heating and/or cooling fluid for heating and/or cooling the flow of liquid product by means of heat exchange between the flows of fluid and the flow of liquid product;    a source of the flow of liquid product to be pasteurized;    receiving means for receiving the pasteurized flow of liquid product;    conduits for flow communication between said elements of the apparatus;    temperature sensing means for sensing the temperature of the liquid product and of said fluid at first points along the flow paths of the liquid product and the fluid, respectively; and    flow rate sensing means for sensing the flow rate of the flows of fluid and of the flow of liquid product;    computing means connected to said temperature sensing means and said flow rate sensing means for receiving measured values of temperatures and flow rates, respectively;    wherein the method comprises the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at said first points;  
 establishing a mathematical model of the apparatus; and  
 based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid at any or all of said second points.  
   
     
     
         15 . The method according to  claim 14 , wherein the number of second points is sufficiently large for obtaining a desired accuracy of the monitoring of said uptake of PU's.  
     
     
         16 . The method according to  claim 14 , wherein the number of second points is selected from the group of values consisting of at least 5, at least 25, at least 50, at least 100, at least 150, at least 200, at least 300, at least 400, at least 500, at least 600, at least 700, at least 800, at least 900, and at least 1,000, the maximum number of said second points being determined by the calculating capacity of a computing means utilized for calculating said number of PU's.  
     
     
         17 . The method according to  claim 14 , wherein said second points consist of sections, cells or finite elements into which at least part and preferably substantially the entire lengths of the paths of flow of the flows of fluid and the flow of liquid product have been subdivided, each such finite element comprising a certain volume of fluid and/or liquid product and being allocated certain parameters for the heat transfer to and from the liquid product and/or to and from the fluid in said each finite element.  
     
     
         18 . A method of controlling the operation of a pasteurizing apparatus for pasteurizing a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, said apparatus comprising: 
 one or more heat exchangers for heating and/or cooling the flow of liquid product;    sources of flows of heating and/or cooling fluid for heating and/or cooling the flow of liquid product by means of heat exchange between the flows of fluid and the flow of liquid product;    a source of the flow of liquid product to be pasteurized;    receiving means for receiving the pasteurized flow of liquid product;    conduits for flow communication between said elements of the apparatus;    temperature sensing means for sensing the temperature of the liquid product and of said fluid at first points along the flow paths of the liquid product and the fluid, respectively;    temperature control means for controlling the temperature of the flows of fluid;    flow rate sensing means for sensing the flow rate of the flows of fluid and of the flow of liquid product;    flow rate control means for controlling the flow rate of the flows of fluid and of the flow of liquid product; and    computing means connected to said temperature sensing means and said flow rate sensing means for receiving measured values of temperatures and flow rates, respectively, to said flow control means for sending signals thereto for controlling said rates of flow and to said temperature control means for sending signals thereto for controlling said temperature of the flows of fluid;    wherein the method comprises the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at said first points;  
 establishing a mathematical model of the apparatus;  
 based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid at any or all of said second points; and  
 by means of said signals sent by the computing means regulating the temperature and/or the rate of flow of one or more of the flows of fluid and/or the rate of flow of the flow of the liquid product such that any unacceptable difference between the calculated uptake of PU's and a desired uptake of PU's for one or more portions of liquid product at corresponding one or more second points is eliminated before said one or more portions exit the apparatus.  
   
     
     
         19 . The method according to  claim 18 , wherein the number of second points is sufficiently large for obtaining a desired accuracy of the controlling of said uptake of PU's.  
     
     
         20 . The method according to  claim 18 , wherein the number of second points is selected from the group of values consisting at least 5, at least 25, at least 50, at least 100, at least 150, at least 200, at least 300, at least 400, at least 500, at least 600, at least 700, at least 800, at least 900, and at least 1,000, the maximum number of said second points being determined by the calculating capacity of a computing means utilized for calculating said number of PU's.  
     
     
         21 . The method according to  claim 18 , wherein said second points consist of sections, cells or finite elements into which at least part and preferably substantially the entire lengths of the paths of flow of the flows of fluid and the flow of liquid product have been subdivided, each such finite element comprising a certain volume of fluid and/or liquid product and being allocated certain parameters for the heat transfer to and from the liquid product and/or to and from the fluid in said each finite element.  
     
     
         22 . A method of controlling the uptake of Pasteurizing Units (PU's) of a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in a pasteurizing apparatus comprising means for exchanging heat between one or more flows of a fluid, preferably water, and the flow of liquid product, said method comprising the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at first points along the paths of flow thereof throughout the apparatus;    establishing a mathematical model of the apparatus;    based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid product at any of said second points;    establishing an ideal PU-uptake value for each of said second points for the uptake of PU's by the liquid product along the path of flow thereof through the apparatus for a given rate of flow of the flow of liquid product, for given rates of flow of the flows of fluid and for given temperatures of the flows of fluid; and    altering the temperature and/or rate of flow of one or more of the flows of fluid and/or the rate of flow of the flow of the liquid product such that all portions of liquid product at the corresponding one or more second points have a PU-uptake at least equal to said ideal PU-uptake value at the corresponding second point.    
     
     
         23 . A method of controlling the uptake of Pasteurizing Units (PU's) of a flow of liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in a pasteurizing apparatus, wherein the apparatus comprises: 
 one or more heat exchangers for heating and/or cooling the flow of liquid product;    sources of flows of heating and/or cooling fluid for heating and/or cooling the flow of liquid product by means of heat exchange between the flows of fluid and the flow of liquid product;    a source of the flow of liquid product to be pasteurized;    receiving means for receiving the pasteurized flow of liquid product;    conduits for flow communication between said elements of the apparatus;    temperature sensing means for sensing the temperature of the liquid product and of said fluid at first points along the flow paths of the liquid product and the fluid, respectively;    temperature control means for controlling the temperature of the flows of fluid;    flow rate sensing means for sensing the flow rate of the flows of fluid and of the flow of liquid product;    flow rate control means for controlling the flow rate of the flows of fluid and of the flow of liquid product; and    computing means connected to said temperature sensing means and said flow rate sensing means for receiving measured values of temperatures and flow rates, respectively, to said flow control means for sending signals thereto for controlling said rates of flow and to said temperature control means for sending signals thereto for controlling said temperature of the flows of fluid;    wherein the method comprises the steps of: 
 measuring consecutive values of the temperature and of the rate of flow of the fluid and the liquid product at said first points;  
 establishing a mathematical model of the apparatus;  
 based on said measured consecutive values and the parameters for the heat transfer between the flows of fluid and the flow of liquid product at a number of second points along said paths of flow, calculating the number of PU's taken up by a portion of liquid at any or all of said second points;  
 establishing an ideal PU-uptake value for each of said second points for the uptake of PU's by the liquid product along the path of flow thereof through the apparatus for a given rate of flow of the flow of liquid product, for given rates of flow of the flows of fluid and for given temperatures of the flows of fluid; and  
 by means of said signals sent by the computing means regulating the temperature and/or the rate of flow of one or more of the flows of fluid and/or the rate of flow of the flow of the liquid product such that all portions of liquid product at the corresponding one or more second points have a PU-uptake at least equal to said ideal PU-uptake value at the corresponding second point.  
   
     
     
         24 . The method according to  claim 23 , wherein the number of second points is sufficiently large for obtaining a desired accuracy of the controlling of said uptake of PU's.  
     
     
         25 . The method according to  claim 23 , wherein the number of second points is selected from the group of values consisting of at least 5, at least 25, at least 50, at least 100, at least 150, at least 200, at least 300, at least  400 , at least 500, at least 600, at least 700, at least 800, at least 900, at least 1,000, the maximum number of said second points being determined by the calculating capacity of a computing means utilized for calculating said number of PU's.  
     
     
         26 . The method according to  claim 23 , wherein said second points consist of sections, cells or finite elements into which at least part and preferably substantially the entire lengths of the paths of flow of the flows of fluid and the flow of liquid product have been subdivided, each such finite element comprising a certain volume of fluid and/or liquid product and being allocated certain parameters for the heat transfer to and from the liquid product and/or to and from the fluid in said each finite element.  
     
     
         27 . An apparatus for pasteurizing a flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, the apparatus comprising: 
 a pasteurizing heat exchanger for exchanging heat between the flow of liquid product and a flow of fluid, preferably water, so as to heat or cool the liquid product during the passage thereof through the pasteurizing heat exchanger;    first conduit means for introducing the flow of liquid product at a product inlet temperature into an inlet of the pasteurizing heat exchanger;    second conduit means for introducing the flow of fluid at a fluid inlet temperature into the pasteurizing heat exchanger;    third conduit means for discharging the flow of liquid product from an outlet of the pasteurizing heat exchanger at a product outlet temperature; and    control means for controlling the rate of flow of the flow of liquid product and/or said product inlet temperature and/or the rate of flow of the flow of fluid and/or said fluid inlet temperature and/or said product outlet temperature such that the flow of liquid product takes up the majority of the Pasteurizing Units (PU's) required for obtaining a desired degree of pasteurization during the passage of said flow of liquid product through the pasteurizing heat exchanger.    
     
     
         28 . The apparatus according to  claim 27 , wherein said majority is selected from the group of values consisting of at least 51%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% and at least 95% of said desired amount of PU's.  
     
     
         29 . The apparatus according to  claim 27  and further comprising: 
 one or more additional pasteurizing heat exchangers comprising the features of the pasteurizing heat exchanger according to  claim 27 , all the heat exchangers being arranged in series and having intermediate conduits for conducting the flow of liquid product from the outlet of one pasteurizing heat exchanger to the inlet of the succeeding pasteurizing heat exchanger; and  
 control means for controlling the rate of flow of the flow of liquid product through the series of pasteurizing heat exchangers and/or said product inlet temperature of at least the first of the heat exchangers in said series and/or the rate of flow of the flow of fluid through at least one and preferably all the heat exchangers in said series and/or said fluid inlet temperature of the flow of fluid introduced into at least one and preferably all the heat exchangers in said series and/or said product outlet temperature of at least the last of the heat exchangers in said series such that the entire flow of liquid product takes up a majority of the Pasteurizing Units, PU's, required for obtaining a desired degree of pasteurization during the passage of said liquid product through said series of pasteurizing heat exchangers.  
 
     
     
         30 . The apparatus according to  claim 29 , wherein said majority is selected from the group of values consisting of at least 51%, at least 55%, at least 60%, at least 65%, at least 70%, at least 75%, at least 80%, at least 85%, at least 90% and at least 95% of said desired amount of PU's.  
     
     
         31 . The apparatus according to  claim 29 , wherein the lengths of said intermediate conduits are substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of fluid.  
     
     
         32 . The apparatus according to  claim 29 , the apparatus further comprising: 
 one or more heat recuperating or regenerative heat exchangers for exchanging heat between the unpasteurized liquid product flowing through said first conduit means into the one or more pasteurizing heat exchangers and the pasteurized liquid product flowing through said third conduit means from the one or more pasteurizing heat exchangers so as to cool the pasteurized liquid product, pre-heat the unpasteurized liquid product to product inlet temperature and recuperate heat energy from the pasteurized liquid product;    the lengths of said first and third conduit means extending between the one or more pasteurizing heat exchangers and the one or more regenerative heat exchangers being substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of said fluid.    
     
     
         33 . An apparatus for pasteurizing a flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, the apparatus comprising: 
 a pasteurizing heat exchanger for exchanging heat between the flow of liquid product and a flow of fluid, preferably water, so as to heat or cool the liquid product during the passage thereof through the pasteurizing heat exchanger;    first conduit means for introducing the flow of liquid product at a product inlet temperature into an inlet of the pasteurizing heat exchanger;    second conduit means for introducing the flow of fluid at a fluid inlet temperature into the pasteurizing heat exchanger;    third conduit means for discharging the flow of liquid product from an outlet of the pasteurizing heat exchanger at a product outlet temperature; and    one or more heat recuperating or regenerative heat exchangers for exchanging heat between the unpasteurized liquid product flowing through said first conduit means into the pasteurizing heat exchanger and the pasteurized liquid product flowing through said third conduit means from the pasteurizing heat exchanger so as to cool the pasteurized liquid product, pre-heat the unpasteurized liquid product to product inlet temperature and recuperate heat energy from the pasteurized liquid product;    the lengths of said first and third conduit means extending between the pasteurizing heat exchanger and the one or more regenerative heat exchangers being substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of said fluid.    
     
     
         34 . The apparatus according to  claim 33 , further comprising one or more additional pasteurizing heat exchangers comprising the features of the pasteurizing heat exchanger according to  claim 33 , all the pasteurizing heat exchangers being arranged in series and having intermediate conduits for conducting the flow of liquid product from the outlet of one pasteurizing heat exchanger to the inlet of the succeeding pasteurizing heat exchanger, and the lengths of said intermediate conduits being substantially as short as possible so as to minimize the volume of liquid product that is not in heat exchange relationship with a flow of fluid.  
     
     
         35 . An apparatus for pasteurizing a flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in a continuous flow and having a heating area, a pasteurizing area and a cooling area, and pump elements for feeding the product in a given flow from the admission opening in the apparatus to its discharge opening, through the above areas in the order in which they are mentioned, whereby the heating, the pasteurizing and the cooling is effected by the transfer of heat between the product itself in cold and in hot condition and a liquid, preferably water, which flows through one or more heat exchangers and a holding pipe without temperature regulation, in the said areas, the areas being divided into zones which extend in the flow direction of the product, and the temperature of the water is adjusted in accordance with the course of the heat transfer aimed at in the zone, wherein one of the part zones is connected to hot and cold water, characterized in that the apparatus between the cold and the hot part of the regenerative heat exchanger contains a pasteurizing part consisting of heat exchangers, said heat exchangers being divided into zones, each of which has a connection for both a heating medium and a cooling medium, or only for a cooling medium in one or more of the zones, the pasteurizing part being connected to the cold and the hot part of the regenerative heat exchanger by means of conduits and the holding pipe solely consisting of said conduits.  
     
     
         36 . A method for the pasteurization of a continuous flow of a liquid product consisting of beer, milk, milk products, fruit juice, fruit juice products or similar consumable liquids, the amount of such liquid product to be pasteurized being at least around 1,000 1/hr, in an apparatus which has a heating area, a pasteurizing area and a cooling area, and pump elements for feeding the product in a given flow from the admission opening in the apparatus to its discharge opening, through the above areas in the order in which they are mentioned, whereby the heating, the pasteurizing and the cooling is effected by the transfer of heat between the product itself in cold and in hot condition and a liquid, preferably water, which flows through one or more heat exchangers and a holding pipe without temperature regulation, in the said areas, the areas being divided into zones which extend in the flow direction of the product, and the temperature of the water is adjusted in accordance with the course of the heat transfer aimed at in the zone, characterized in that: 
 one of the pasteurizing zones is connected to hot and cold water;    the pasteurizing area is divided into a number of individual pasteurizing zones with connection for both heating and cooling or, in the event of a stop in production, for cooling of the product in order to hold the temperature under the pasteurizing temperature, and upon restarting to heat the product again to a temperature close to the pasteurizing temperature;    the pasteurizing area is connected to the heating area and the cooling area by means of conduits; and    the holding pipe solely consists of said conduits.    
     
     
         37 . An apparatus for the pasteurizing of liquid products in a continuous flow, the apparatus comprising: 
 a regenerative part into which the product is fed by a supply pump;    a pasteurizing part to which the product is led from the regenerative part and from which pasteurizing part the product is led back to the regenerative part, both the regenerative part and the pasteurizing part consisting of heat exchangers;    a mixing valve for supplying hot or cold water to the pasteurizing part, so that the pasteurizing part cannot only heat the product to the pasteurization temperature, but also cool the product down in the event of a stop in production; and    temperature sensors placed before and after the pasteurizing part for controlling the pasteurization process..    
     
     
         38 . The apparatus according to  claim 37 , wherein the apparatus comprises two main heat exchangers, a regenerative heat exchanger which is divided into two zones, and a pasteurizing heat exchanger which is divided into three zones.  
     
     
         39 . The apparatus according to  claim 38 , wherein a temperature sensor is placed after each of said three pasteurizing zones so as to register whether or not the necessary temperatures have been achieved so that heating and cooling, respectively can be controlled on the secondary side of the pasteurizing heat exchanger.  
     
     
         40 . A method for the pasteurizing of liquid products in a continuous flow, comprising the steps of: 
 providing a regenerative part of a pasteurizing apparatus and a pasteurizing part of said pasteurizing apparatus, both the regenerative part and the pasteurizing part comprising heat exchangers;    feeding product into the regenerative part;    leading the product from the regenerative part to the pasteurizing part;    leading the product from the pasteurizing part back to the regenerative part;    heating the product in the regenerative part by transfer of heat from the product led back to the regenerative part from the pasteurizing part;    heating the product to the pasteurization temperature in the pasteurizing part and cooling the product down in the pasteurizing part in the event of a production stop by supplying hot or cold water, respectively, to the pasteurizing part; and    controlling the pasteurization process by means of temperature sensors placed before and after the pasteurizing part.    
     
     
         41 . The method according to  claim 40 , wherein the pasteurizing apparatus comprises two main heat exchangers, a regenerative heat exchanger which is divided into two zones, and a pasteurizing heat exchanger which is divided into three zones.  
     
     
         42 . The method according to  claim 41 , comprising the further steps of: 
 providing a temperature sensor placed after each of said three pasteurizing zones;    by means of said temperature sensors registering whether or not the necessary temperatures have been achieved; and    based on said registration by said temperature sensors, controlling heating and cooling, respectively, on the secondary side of the pasteurizing heat exchanger.