Apparatus And Method For Forming Melt-Formed Inorganic Fibres

Abstract

Apparatus and methods for forming melt-formed fibres and melt-formed biosoluble fibers are disclosed. The apparatus comprises a spinning head comprising one or more rotors; a plurality of nozzles or slots disposed around at least part of the one or more rotors; a conveyor; and a barrier between the spinning head and the conveyor.

1 . Apparatus for forming melt-formed inorganic fibres comprising:—
 a source of molten material;
 a fibre forming region housing: 
 a spinning head comprising one or more rotors each having an axis of rotation, at least one rotor being configured to receive molten material from the source of molten material at a region of the rotor to which melt is delivered; 
 a plurality of nozzles or slots disposed around at least part of the one or more rotors, configured to supply a stream of gas at a velocity in excess of 40 m·s −1 ; 
 the fibre forming region being delimited at an end remote from the at least one rotor by a barrier; 
 a wool bin beyond the barrier to receive fibres from the fibre forming region 
 a conveyor disposed to receive fibres produced from the molten material and settling from the wool bin; and 
 the barrier being between the spinning head and the conveyor, 
 
 an upper edge of the barrier lying below a horizontal line lying in a first vertical plane including the axis of rotation of at least one rotor of the one or more rotors and the horizontal line intersecting the intersection of the axis of rotation with a second vertical plane orthogonal to the first vertical plane and including a vertical line through said region of the rotor to which melt is delivered, the included angle θ between the horizontal line and a line in the first vertical plane joining the upper edge of the barrier and the intersection of the horizontal line and axis of rotation being in the range 40°-85°, the spinning head, barrier, and conveyor being disposed to permit fibres carried by the stream of gas to pass over the upper edge of the barrier to the conveyor. 
 
     
     
         2 . The apparatus, according to claim Error! Reference source not found., in which at least one of the one or more rotors has an acceleration at its periphery in excess of 200 km·s −2 . 
     
     
         3 . A method for forming melt-formed inorganic fibres comprising the use of apparatus of  claim 1  by:
 impinging a stream of molten material on one or more of the rotors, while passing a stream of gas from the nozzles or slots over at least one of the one or more rotors, such that fibres produced from the melt are carried by the stream of gas from the rotors and pass over the upper edge of the barrier to the conveyor and material not passing over the upper edge being rejected. 
 
     
     
         4 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 1 , in which the gas velocity at a distance of 50 mm from the nozzles or slots is in excess of 50 m·s −1 . 
     
     
         5 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 1 , in which the stream of molten material is of a composition such that the fibres produced from the melt are aluminosilicate fibres. 
     
     
         6 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 1 , in which the stream of molten material is of a composition such that the fibres produced from the melt are alkaline earth silicate fibres. 
     
     
         7 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the fibres comprise in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   45%-85% 
                 
                     
                   alkaline earth oxide 
                   15%-55% 
                 
                     
                   components other than alkaline 
                   0 to 20% 
                 
                     
                   earth oxides and silicon dioxide 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
               
            
           
         
       
     
     
         8 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 7 , in which the fibres comprise in weight percent:
 SiO 2 : 70-80%   CaO+MgO: 18-25%   Other: <3%.   
     
     
         9 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 7 , in which the stream of molten material is of a composition such that the fibres produced from the melt comprise at least 1% by weight each of calcium oxide and magnesium oxide, and optionally comprise up to 20% by weight of components other than calcium oxide, magnesium oxide and silicon dioxide. 
     
     
         10 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the fibres comprise in weight percent:—
 SiO 2 : 62-68% 
 CaO: 26-32% 
 MgO: 3-7% 
 Others: <1%. 
 
     
     
         11 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the stream of molten material is of a composition such that the fibres produced from the melt are magnesium silicate fibres comprising less than 1% by weight of calcium oxide, at least 1% magnesium oxide, and optionally comprise up to 20% by weight of components other than calcium oxide, magnesium oxide and silicon dioxide. 
     
     
         12 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the fibres comprise in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   65-86% 
                 
                     
                   MgO 
                   14-35% 
                 
                     
                   components other than MgO or SiO 2   
                       0-20%. 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
               
            
           
         
       
     
     
         13 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the stream of molten material is of a composition such that the fibres produced from the melt comprise at least 1% by weight of calcium oxide, less than 1% magnesium oxide, and optionally comprise up to 20% by weight of components other than calcium oxide, magnesium oxide and silicon dioxide. 
     
     
         14 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 6 , in which the fibres comprise in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   72-74.5%  
                 
                     
                   CaO 
                   22.2-26%  
                 
                     
                   MgO 
                   0.4-0.8% 
                 
                     
                   Al 2 O 3   
                   0.9-1.4% 
                 
                     
                   K 2 O 
                    0.5-0.8%. 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
               
            
           
         
       
     
     
         15 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 1 , in which the stream of molten material is of a composition such that the fibres produced from the melt are alkali metal aluminosilicate fibres. 
     
     
         16 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 15 , in which the fibres comprise in mole percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   Al 2 O 3   
                   5-90 mol % 
                 
                     
                   K 2 O 
                   12-40 mol %  
                 
                     
                   SiO 2   
                   5-80 mol % 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
               
            
           
         
         in which SiO 2 +Al 2 O 3 +K 2 O >=80 mol %. 
       
     
     
         17 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 15 , in which the fibres comprise in weight percent:
 Al 2 O 3 36±1.5 wt %   K 2 O 25.5±1.5 wt %   SiO 2  31±1.5 wt %   ZrO 2  6.5±0.5 wt %   MgO 1±0.2 wt %   with the total of these components being 99%-100% by weight.   
     
     
         18 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 15 , in which the fibres comprise in weight percent:
 SiO 2 : 62-68%;   CaO: 26-32%;   MgO: 3-7%; and   Others: less than 1%,   the mass of melt-formed biosoluble fibres having a length weighted arithmetic mean diameter less than 2 μm and comprising fibres of a length greater than 10 cm, the mass having a shot content of shot having a dimension greater than 45 μm of less than 35 wt %, and capable of being formed by entanglement into a blanket having:   a density of 128 kg·m-3;   a thickness of 25 mm;   and   a tensile strength greater than 50 kPa from a blanket sample of 230±5 mm×75±2 mm and clamped at each end with an unclamped span of 150±5 mm, wherein the mass of melt-formed biosoluble fibers is a non-deshotted mass of melt-formed biosoluble fibers having a mass of more than 100 grams.   
     
     
         19 . The method for forming the mass of melt-formed biosoluble fibres according to  claim 15 , in which the fibres comprise in weight percent:
 SiO 2 : 70-80%;   CaO+MgO: 18-25%; and   Other: less than 3%   the mass of melt-formed biosoluble fibres having a length weighted arithmetic mean diameter less than 2 μm and comprising fibres of a length greater than 10 cm, the mass having a shot content of shot having a dimension greater than 45 μm of less than 35 wt %, and capable of being formed by entanglement into a blanket having:   a density of 128 kg·m −3 ;   a thickness of 25 mm;   a tensile strength greater than 50 kPa from a blanket sample of 230±5 mm×75±2 mm and clamped at each end with an unclamped span of 150±5 mm; and   having a thermal conductivity at 1000° C. of less than or equal to 0.26 W·m −1 ·K −1 , wherein the mass of melt-formed biosoluble fibers is a non-deshotted mass of melt-formed biosoluble fibers having a mass of more than 100 grams.   
     
     
         20 . The method for forming the mass of melt-formed fibres according to  claim 15 , in which the fibres comprise in weight percent: 
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                   SiO 2   
                   73-74.5%;  
                 
                     
                   CaO 
                   22.2-26%;  
                 
                     
                   MgO 
                   0.4-0.8%; 
                 
                     
                   Al 2 O 3   
                   0.9-1.4%; and 
                 
                     
                   K 2 O 
                   0.5-0.8%, 
                 
                     
                     
                 
             
                
               
               
                
                
                
                
                
                
               
            
           
         
         the mass of melt-formed biosoluble fibres having a length weighted arithmetic mean diameter less than 2 μm and comprising fibres of a length greater than 10 cm, the mass having a shot content of shot having a dimension greater than 45 μm of less than 35 wt %, and capable of being formed by entanglement into a blanket having: 
         a density of 128 kg·m −3 ; 
         a thickness of 25 mm; 
         a tensile strength greater than 50 kPa from a blanket sample of 230±5 mm×75±2 mm and clamped at each end with an unclamped span of 150±5 mm; and 
         having a thermal conductivity at 1000° C. of less than or equal to 0.26 W·m −1 ·K −1 , wherein the mass of melt-formed biosoluble fibers is a non-deshotted mass of melt-formed biosoluble fibers having a mass of more than 100 grams.