Method and apparatus for melt-spinning and cooling a plurality of filaments

Abstract

A method and an apparatus for melt-spinning and cooling a plurality of filaments which are processed to form a non-woven fabric or web. The filaments are guided after extrusion in the form of a filament curtain through a cooling zone and are cooled by a cooling air stream blown transversely to the filament curtain. In order to prevent the flow effects created by air swirls in the side edge zones of the filament curtain, an additional quenching air stream acts inside the cooling zone on each side edge of the filament curtain. For this purpose, the inventive apparatus comprises a quenching member positioned below each longitudinal end of the spinneret.

1 . A method for melt spinning and cooling a plurality of filaments comprising the steps of 
 melt spinning a plurality of downwardly advancing filaments in the form of an elongate curtain which defines opposite side edges and a longitudinal direction extending between the side edges,    guiding the downwardly advancing filaments through a cooling zone, and    cooling the downwardly advancing filaments inside the cooling zone by directing a cooling air stream transversely toward the filaments along the longitudinal length of the curtain, and directing a quenching air stream transversely toward the filaments at at least one of the side edges of the curtain.    
   
   
       2 . The method of  claim 1 , wherein the quenching air stream comprises a separate quenching air stream acting on each side edge of the filament curtain and which are oriented to be transverse to the cooling air stream.  
   
   
       3 . The method of  claim 2 , wherein the separate quenching air streams at the side edges of the filament curtain are each oriented to have a directional component which extends in the advancing direction of the filaments and to form a quench angle of between about 0° and 45° between the advancing filaments and the associated separate quenching air stream.  
   
   
       4 . The method of  claim 3 , wherein each separate quenching air stream forms a quench angle of less than about 20° at the associated side edge of the filament curtain.  
   
   
       5 . The method of  claim 1  wherein the cooling air stream and the quenching air stream both operate at an inlet region of the cooling zone.  
   
   
       6 . The method of  claim 1  wherein the quenching air stream has an air speed greater than the air speed of the cooling air stream.  
   
   
       7 . The method of  claim 1 , wherein the cooling air stream and the quenching air stream are each temperature controlled so as to have substantially the same temperature.  
   
   
       8 . The method of  claim 1 , wherein the cooling air stream has a component acting on each of the longitudinal sides of the curtain inside the cooling zone, and so that the components are directed toward each other.  
   
   
       9 . The method of  claim 1 , comprising the further step of positioning a pair of laterally adjustable cover plates adjacent said at least one side edge of the curtain to control the air flow along the at least one side edge of the curtain.  
   
   
       10 . A method for melt spinning and cooling a plurality of filaments comprising the steps of 
 melt spinning a plurality of downwardly advancing filaments in the form of an elongate curtain which defines opposite side edges and a longitudinal direction extending between the side edges,    guiding the downwardly advancing filaments through a cooling zone, and    cooling the downwardly advancing filaments inside the cooling zone by directing a cooling air stream transversely toward the filaments along the longitudinal length on each side of the curtain, and directing a quenching air stream transversely toward the filaments at each side edge of the curtain, and    wherein the cooling air streams are directed toward each other and the quenching air streams are directed toward each other and transverse to the cooling air streams.    
   
   
       11 . An apparatus for melt spinning and cooling a plurality of filaments comprising 
 an elongate spinneret for extruding a plurality of downwardly advancing filaments in the form of an elongate curtain which defines opposite side edges and a longitudinal direction extending between the side edges, said spinneret comprising opposite longitudinally extending sides and opposite ends,    a cooling unit arranged below the spinneret and including 
 (a) a cooling wall oriented to extend parallel to one of the longitudinally extending sides of the spinneret, with a cooling chamber connected to the cooling wall so that a cooling air stream can be directed transversely toward the downwardly advancing filaments along the longitudinal length of the curtain, and  
 (b) at least one quenching member positioned adjacent at least one of the ends of the spinneret for directing a quenching air stream transversely toward the advancing filaments at at least one of the side edges of the curtain.  
   
   
   
       12 . The apparatus of  claim 11 , wherein the at least one quenching member is oriented to generate a quenching air stream which is transverse to the direction of the cooling air stream.  
   
   
       13 . The apparatus of  claim 12 , wherein the at least one quenching member comprises a quench opening oriented towards the side edge of the filament curtain and a pressure chamber connected to the quench opening, and wherein the quench opening has an inclination for forming a quenching angle (α) in a range between about 0° and 45° between the filaments and the quenching air stream.  
   
   
       14 . The apparatus of  claim 11 , wherein a cooling wall and an associated cooling chamber are positioned on each side of the filament curtain, and a quenching member is positioned adjacent each of the ends of the spinneret.  
   
   
       15 . The apparatus of  claim 14 , wherein the quenching member on each end of the spinneret comprises a quench opening which has an inclination for forming a quenching angle (α) in a range less than about 20° between the filaments and the associated quenching air stream.  
   
   
       16 . The apparatus of  claim 15 , wherein each quench opening has a rectangular outlet in cross-section, which extends essentially parallel to the adjacent end of the spinneret and over the depth of the filament curtain.  
   
   
       17 . The apparatus of  claim 16 , wherein a flow straightener is arranged inside each quench opening.  
   
   
       18 . The apparatus of  claim 11 , wherein the at least one quenching member is arranged in an inlet region of the cooling unit.  
   
   
       19 . The apparatus of  claim 11 , wherein the cooling chamber and the at least one quenching member are connected to a common cooling air source.  
   
   
       20 . The apparatus of  claim 11 , wherein the cooling unit comprises a second cooling wall having a second cooling chamber on the opposite longitudinal side of the spinneret, wherein said second cooling chamber directs a second cooling air stream transversely to the filament curtain opposite to the first mentioned cooling air stream.  
   
   
       21 . The apparatus of  claim 11 , wherein a pair of cover plates are positioned adjacent the at least one quenching member, wherein said cover plates extend at a distance from and parallel to one of the side edges of the filament curtain and are constructed to be displaceable.