Cooling method and cooling equipment of extruded article

Abstract

A part of outer circumference of an extruded article that is difficult to be cooled is selectively pre-cooled by a pre-cooler ( 18 ) and is cooled by a cooling fan ( 17 ) by forcible air-cooling and the temperature of the portion that is difficult to be cooled becomes lower than the other portion, so that the outer circumference is not cooled in an imbalanced manner during subsequent forcible air-cooling process, thereby avoiding bent of the extruded article.

What is claimed is:  
     
         1 . A cooling method, comprising the steps of: 
 hot-extrusion molding an extruded article by an extruder;    when a part of the outer circumference of the extruded article has a cross section more difficult to be cooled than the other part, pre-cooling the difficult-to-be-cooled part and subsequently forcibly air-cooling the extruded article; and    when the extruded article has a cross section capable of approximately uniformly cooling the outer circumference thereof, forcibly air-cooling the extruded article without pre-cooling.    
     
     
         2 . A cooling equipment for an extruded article, comprising: 
 a main cooler provided on an extrusion side of an extruder for blowing air to an extruded article for forcibly air-cooling the extruded article; and    a pre-cooler provided between the main cooler and the extruder, the pre-cooler comprising: an upper cooler for cooling the extruded article from an upper side thereof; a lower cooler for cooling the extruded article from a lower side thereof; a first side-cooler for cooling the extruded article from a first lateral side thereof; and a second side-cooler for cooling the extruded article from a second lateral side thereof, the upper cooler, the lower cooler and the first and the second side-coolers being selectively actuated in accordance with the cross section of the extruded article.    
     
     
         3 . The cooling equipment according to  claim 2 , 
 wherein the respective coolers of the pre-cooler discharge a cooling medium on the outer circumference of the extruded article to cool the extruded article,    wherein the position for the upper and the lower coolers to discharge the cooling medium can be changed in a direction orthogonal with extrusion direction of the extruded article, and    wherein the position for the first and the second side-coolers to discharge the cooling medium can be vertically changed.    
     
     
         4 . The cooling equipment according to  claim 2 , wherein the upper cooler and the first and the second side-coolers are divided into a plurality of components along extrusion direction of the extruded article, and the divided components are capable of independent movement to a cooling position and an escape position.