Sequential Cooling Methods and Apparatus

Abstract

A method of cooling and a cooling installation in which the method can be carried out includes two or more separate compartments ( 34 ) for receiving product so as to cool the product by sequential movement through each compartment in turn wherein the temperature drop in any one compartment reduces the temperature of exit of the product to a temperature about half of the temperature of introduction of the product to the compartments ( 34 ). Advantages of the present invention include that the time taken to cool the product to the required temperature is considerably reduced as the cooling is more effective. The present invention finds particular application to treating fresh produce such as fresh fruit and vegetables, particularly table grapes so as to reduce the incidence of spoilage or deterioration and to increase the usable shelf life.

1 . A method of cooling a product, particularly a food product or material comprising the steps of providing the product in a container and subjecting the product to a cooling environment in order to cool the product located in the container characterised in that each individual item of product in the container is subjected to a cooling environment so as to more or less substantially uniformly cool the product to reduce or minimise the variability of storage properties or characteristics of the product.  
   
   
       2 . A method of minimising and/or reducing the extent of deterioration or degradation of a product, particularly a food material comprising the steps of forming or harvesting the product, packing the product into a container, exposing the product in the container to a cooling environment at a temperature lower than the temperature at which the product was packed characterised in that the container is provided with a means for ventilation, allowing the cooling environment to pass through the container, thereby subjecting substantially all of the product in the container to substantially the same cooling environment thereby minimising the variability of storage properties or characteristics of the product in the container.  
   
   
       3 . A method of cooling a product using a cooling structure having a least two adjacent sections for providing a cooling environment characterised in that the method includes packing a product into a container at an initial temperature, locating the container in the first of the two adjacent sections at or towards one end of the conveyor means located at least partially within the cooling structure and capable of moving within the cooling structure, periodically moving the conveyor in order to advance intermittently the container on the conveyor through the sections of the cooling structure in turn, such that the container remains in at least each section of the cooling structure for a time sufficient to cool the product to a temperature less than the initial temperature and/or to less than the temperature at which the container exits from the section located immediately preceding the section to which the container is moved and wherein the product within the container is subjected to the cooling environment so as to more or less substantially uniformly cool the product by the cooling environment passing through the container so as to enhance storage properties of the product and/or to reduce the time taken to cool the product to a temperature acceptable for storage.  
   
   
       4 . A cooling installation for cooling a product in which the installation is provided with two or more discreet separate or separable compartments or areas arranged such that the product is moved sequentially through the installation from one of the compartments to the other compartment such that the product is subjected to a cooling environment by periodically moving the product through the compartments.  
   
   
       5 . A method according to  claim 1 , further comprising a step of pre-cooling the product to a moderate temperature by exposing the product to a cooling environment at a temperature lower than ambient temperature.  
   
   
       6 . A method according to  claim 1  characterised in that the product is an edible or non-edible product including a manufactured or processed product or a fresh product.  
   
   
       7 . A method according to  claim 1  characterised in that the cooling environment has different parts, sections, regions, areas or similar for subjecting the product to different temperatures such as a temperature of less than about 15° C., preferably less than about 12° C., preferably less than 8° C., more preferably lower than 4° C. and most preferably between about 0°-1° C.  
   
   
       8 . A method according to  claim 1  characterised in that the cooling environment is provided by a forced air flow, preferably a fan forced air flow and more preferably a tube axial fan.  
   
   
       9 . A method according to  claim 1  characterised in that the cooling environment is a moist environment or a moisture free environment.  
   
   
       10 . A method according to  claim 1  characterised in that the relative humidity of the cooling environment is determined by the temperature differential across the air cooling coils, the rate of cooling and the amount of moisture condensed onto the cooling coils provided for each cooling section of the installation.  
   
   
       11 . A method according to  claim 1  characterised in that there is at least one cooling tunnel comprising one, two, three, four or more cooling compartments.  
   
   
       12 . A method according to  claim 1  characterised in that there is a single cooling layer or multiple cooling layers such as two superposable layers located one on top of the other.  
   
   
       13 . A method according to  claim 1  characterised in that the product is located in a container when in the cooling compartment wherein the container is provided with one or more ventilation means allowing passage of air through the container to substantially cool each individual item in the container.  
   
   
       14 . A method according to  claim 13  characterised in that the ventilation means includes one or more slots, apertures, perforations, openings or passages provided in the base and/or walls of the container allowing air to pass therethrough for circulation and/or recirculation through the container.  
   
   
       15 . A method according to  claim 1  characterised in that the sides of the container are provided with baffles, deflectors, seals or guides to direct air flow through the containers wherein the guide is a flap, plate, wing, vane or similar for directing the air flow through the container or for sealing the container to force air flow through the container.  
   
   
       16 . A method according to  claim 15  characterised in that the guide is mounted or hinged for pivotable movement with respect to the container.  
   
   
       17 . A cooling installation according to  claim 4  characterised in that the compartment is provided with a conveyor system for transporting the product through the compartment wherein the conveyor allows movement therethrough and around the conveyor.  
   
   
       18 . A cooling installation according to  claim 17  characterised in that the conveyor is an open conveyor in the form of a link chain conveyor or roller conveyor having spaced apart elements.  
   
   
       19 . A cooling installation according to  claim 17  characterised in that the conveyor moves intermittently or continuously.  
   
   
       20 . A cooling installation according to  claim 17  characterised in that the conveyor moves periodically with the time interval between movements from about 0.1 to about 10 minutes, preferably from about 0.1 to 5 minutes, more preferably from about 0.5 to 3 minutes, most preferably from about 1 to about 2.5 minutes.  
   
   
       21 . A method according to  claim 1  characterised in that the produce is table grapes.  
   
   
       22 . A method or cooling installation according to  claim 11  characterised in that the cooling tunnel is divided into six separable compartments or cells located sequentially in line allowing containers of product to pass through each compartment in turn as they are transported through the tunnel.  
   
   
       23 . A method according to  claim 11  characterised in that there is a multiplicity barriers located at spaced apart locations to divide the tunnel into the compartments wherein the barriers are fixed barriers, adjustable barriers or movable barriers arranged to prevent or minimise the loss of heat from the compartments.  
   
   
       24 . A cooling installation according to  claim 4  characterised in that each compartment is provided with an air flow rate of cool air wherein the air flow rate is up to 10 litres of air per kilogram of product per second being treated in the tunnel, preferably a rate of from 0.5 to about 10 l/kg/s, more preferably from 1 to 5 l/kg/s, more preferably 1 to 3 l/kg/s and most preferably about 2 l/kg/s.  
   
   
       25 . A cooling installation according to  claim 4  characterised in that the temperature is reduced from about 16° C. to about 20° C. in the first compartment.  
   
   
       26 . A method according to  claim 1  characterised in that the container resides in a compartment from about 0.1 to about 30 minutes, preferably from about 0.5 to 20 minutes, more preferably from about 3 to 15 minutes, even more preferably from about 5 to 12 minutes and most preferably from about 8 to 10 minutes.  
   
   
       27 . A cooling installation according to  claim 4  characterised in that the temperature in the first compartment is reduced from about 16° to about 8° C., in the second compartment from about 8° C. to about 4° C., in the third compartment from about 4° C. to about 2°, in the fourth compartment from about 2° C. to about 1° C., in the fifth compartment from about 1° C. to 0.5° C. and in the sixth compartment from about 0.5° C. to about 0° C.  
   
   
       28 . A cooling installation according to  claim 4  characterised in that each compartment is provided with at least one sealed barrier for preventing heat loss wherein the barrier is provided with a seal.  
   
   
       29 . (canceled)