Method of manufacturing feed pellets and plant for use in the implementation of the method

Abstract

A method of manufacturing feed pellets, and a plant for the implementation of this method have been explained. The aim has been to improve the manufacturing of porous pellets, first and foremost to achieve a better control of the porosity than by known technique. The pellets come from a pelletizing machine ( 1 ) into a pellet chamber ( 3 ) which is kept at a pressure lower than the ambient pressure. From the chamber ( 3 ) the pellets are passed through an outlet ( 5 ) having a gate lock body ( 6 ).

1 - 22 . (canceled)  
     
     
         23 . A method for manufacturing feed pellets having an initial pore volume and fat content said method comprising: 
 A. extruding pellets from a feed material within a pellet extruder having a discharge nozzle;    B. exposing said extruded pellets to a first pressure lower than ambient pressure immediately subsequent to said extruding step, said exposure to said first pressure occurring in a pellet chamber downstream from said discharge nozzle, whereby said pellets expand and increase said pore volume; and    C. subsequently adding oil to said pellets to increase said fat content for said pellets:    
     
     
         24 . The method of  claim 23  further comprising a drying step.  
     
     
         25 . The method of  claim 24  wherein said drying step is conducted prior to adding oil to said pellets.  
     
     
         26 . The method of  claim 25  wherein said drying step is drying in air.  
     
     
         27 - 30 . (canceled)  
     
     
         31 . The method of  claim 23  wherein the step of adding oil to said pellets comprises coating said pellets with oil.  
     
     
         32 . The method of  claim 23  wherein the step of adding oil to said pellets comprises adding said pellets to a hot oil bath.  
     
     
         33 . The method of  claim 23  wherein the step of adding said oil to said pellets is conducted in a vacuum chamber, said vacuum chamber comprising a hot oil bath.  
     
     
         34 . The method of  claim 33  wherein said vacuum chamber is at a second pressure which is lower than ambient.  
     
     
         35 . The method of  claim 34  wherein said second pressure is different than said first pressure.  
     
     
         36 . The method of  claim 23  wherein the step of adding said oil to said pellets is conducted in a vacuum chamber.  
     
     
         37 . The method of  claim 36  wherein said vacuum chamber is at a second pressure which is lower than ambient.