Method of Producing an Insulated Exhaust Gas Device

Abstract

A method is provided for producing an exhaust gas aftertreatment or acoustic device ( 18 ) having a maximum operating temperature Tmax. The method includes the steps of providing a blanket ( 28 ) of silica fiber insulation material having a weight percentage of SiO 2 of greater than 65%; heating the blanket ( 28 ) so that all of silica fiber insulation material is raised to a temperature T greater than Tmax; and installing the blanket ( 28 ) in the device ( 18 ) after the heating step.

1 . A method of producing an exhaust gas aftertreatment or acoustic device having a maximum operating temperature Tmax, the method comprising the steps of:
 providing a blanket of silica fiber insulation material having a weight percentage of SiO 2  of greater than 65%;   heating the blanket so that all of silica fiber insulation material is raised to a temperature T greater than Tmax; and   installing the blanket in the device after the heating step.   
     
     
         2 . The method of  claim 1  wherein T is at least 1.05×Tmax. 
     
     
         3 . The method of  claim 1  wherein the installing step comprises installing the blanket so that the blanket is compressed between two adjacent surfaces of the device to achieve an average installed density of 0.18 grams/cubic centimeter to 0.30 grams/cubic centimeter of the insulation material in the blanket. 
     
     
         4 . The method of  claim 1  wherein during the heating step the blanket is an uncompressed state. 
     
     
         5 . The method of  claim 1  wherein during the heating step the blanket is heated in a rolled state wherein the blanket has been formed into a roll having a central axis. 
     
     
         6 . The method of  claim 5  wherein during the heating step the blanket is rotated about the central axis. 
     
     
         7 . The method of  claim 1  wherein during the heating step the blanket is planar. 
     
     
         8 . The method of  claim 1  wherein Tmax is within the range of 300° C. to 1100° C. 
     
     
         9 . The method of  claim 1  wherein the installing step comprises installing the blanket so that the blanket encircles a core of the device through which the exhaust gas passes. 
     
     
         10 . The method of  claim 1  wherein the silica fiber insulation material has a weight percentage of SiO 2  of greater than 95%. 
     
     
         11 . A method of producing an exhaust gas aftertreatment or acoustic device having a maximum operating temperature Tmax, the method comprising the steps of:
 providing a blanket of silica fiber insulation material having a weight percentage of SiO 2  of greater than 65%;   heating the blanket so that all of silica fiber insulation material is raised to a temperature T greater than Tmax; and   installing the blanket in the device after the heating step so that the blanket encircles a core of the device through which the exhaust gas passes and the blanket is compressed between two adjacent surfaces of the device to achieve an average installed density of 0.18 grams/cubic centimeter to 0.30 grams/cubic centimeter of the insulation material in the blanket.   
     
     
         12 . The method of  claim 11  wherein T is at least 1.05×Tmax. 
     
     
         13 . The method of  claim 11  wherein during the heating step the blanket is an uncompressed state. 
     
     
         14 . The method of  claim 11  wherein during the heating step the blanket is heated in a rolled state wherein the blanket has been formed into a roll having a central axis. 
     
     
         15 . The method of  claim 14  wherein during the heating step the blanket is rotated about the central axis. 
     
     
         16 . The method of  claim 11  wherein during the heating step the blanket is planar. 
     
     
         17 . The method of  claim 11  wherein Tmax is within the range of 300° C. to 1100° C. 
     
     
         18 . The method of  claim 11  wherein the silica fiber insulation material has a weight percentage of SiO 2  of greater than 95%. 
     
     
         19 . The method of  claim 11  wherein the two adjacent surfaces are cylindrical surfaces.