Method and device for producing a mineral wool nonwoven fabric

Abstract

A device for producing a mineral wool nonwoven fabric, comprising a drop shaft and fibrillation devices in addition to a conveyor device for the conveyance of mineral wool nonwoven fabric. A device is also provided to separate the strip of insulating material into a first section and a second section in a longitudinal direction. A conveyor device directs the first section in such a way that it is placed on the second section. The device enables a mineral fiber product to be created with a density distribution that is such that the upper area and the lower area have a higher density than the area located inbetween.

What is claimed:  
     
         1 . A method for producing mineral wool nonwoven fabric ( 52 ) comprising the steps: 
 fiberizing the raw material in at least one fiberizing means ( 26   a ,  26   b );    depositing the fibers on a collection conveyor ( 16 ) of a shroud ( 10 ) for forming a primary nonwoven ( 24 );    slitting said primary nonwoven in longitudinal direction so that a first blanket section ( 38 ) and a second blanket section ( 40 ) materialize;    transporting said first blanket section ( 38 ) and said second blanket section ( 40 ) such that the conveying distances between shroud and curing oven are longitudinally staggered;    inverting said first blanket section ( 38 ) so that the underside of said first blanket section ( 38 ) is located upwards; and    depositing said first blanket section ( 38 ) on said second blanket section ( 40 ) to form a secondary nonwoven ( 52 ).    
     
     
         2 . A method according to  claim 1 , wherein slitting said primary nonwoven in longitudinal direction is executed with a water cutting jet.  
     
     
         3 . A mineral wool blanket or mineral wool mat of cross-linked mineral wool fibers including a density distribution across the thickness (z); 
 the upper portion ( 24   b ) and the lower portion ( 24   b ) of said mineral wool blanket or mineral wool mat each exhibiting a density higher than that of the portion ( 56 ) located between said upper portion and said lower portion; and fiberizing the raw material in at least one fiberizing mean ( 26 ,  26   b );    each of said upper portion and lower portion of said mineral wool blanket or mineral wool mat being deposited in a collection conveyor ( 16 ) of a shroud ( 10 ) for forming a primary nonwoven ( 24 ); and including    two layers exhibiting identical properties as regards the fiber quality and/or the binder content and the layers exhibiting identical density gradients,    wherein the density distribution across the thickness (z) of the blanket or the mat comprise in the portion ( 56 ) located between said upper portion and said lower portion a value of constant density and that the said density distribution increases in the upper and lower portion ( 24   b ) like a mirror-image.    
     
     
         4 . Mineral wool blanket or mat according to  claim 3 , wherein the density distribution in the portion ( 56 ) located between said upper portion and said lower portion exhibits a minimum value and exhibits a maximum value in the border portion of the upper and the lower portion ( 24   b ).  
     
     
         5 . Mineral wool blanket or mat according to  claim 3 , wherein the mineral wool blanket or mineral wool mat has a density in the range of 4 to 70 kg/m3.  
     
     
         6 . Mineral wool blanket or mat according to  claim 3 , wherein the thickness of said mineral wool blanket or mineral wool mat is in the range of 50 to 500 mm.  
     
     
         7 . Mineral wool blanket or mat according to  claim 3 , wherein said upper portion ( 24   b ) and said lower portion ( 24   b ) of said mineral wool blanket or mineral wool mat comprises in each case a higher binder content.  
     
     
         8 . Mineral wool blanket or mat according to  claim 3 , wherein the binder content in said upper portion and said lower portion is roughly 1% to 4% above the average binder content.  
     
     
         9 . Mineral wool blanket or mat of cross-linked mineral wool fibers including a density distribution across the thickness (z) according to  claim 3 , wherein the average density is in the range 4 to 11 kg/m3, whereby said blanket or mat comprises homogenous mass distributions transversely.  
     
     
         10 . Mineral wool blanket or mat according to  claim 5 , wherein the density is 4 to 25 kg/m3.  
     
     
         11 . Mineral wool blanket or mat according to  claim 6 , wherein the thickness is in the range of 120 to 360 mm.  
     
     
         12 . Mineral wool blanket or mat according to  claim 8 , wherein the binder content is 1% to 2% above the average binder content.  
     
     
         13 . Mineral wool blanket or mat according to  claim 9 , wherein the average density is 4 to 9 kg/m3.  
     
     
         14 . Mineral wool blanket or mat according to  claim 10 , wherein the average density is 4 to 6 kg/m3.