Methods, materials, and equipment to form improved fit duct liner insulation for round and oval hvac duct systems

Abstract

The embodiments described herein relate generally to improved fit duct liner insulation for curvilinear ducts in HVAC, exhaust, or other similar gas flow systems. A duct liner insulation for a curvilinear duct may include an insulation board having a first major surface and a second major surface. The duct liner insulation further includes a plurality of rows of kerfs in the first major surface of the insulation board configured to allow the insulation board to flex in a direction of the width of the insulation board such that insulation board is foldable into a curvilinear configuration. Each of the kerfs has a v-shaped cross section with sidewalls extending from a kerf base portion at or near the second major surface of the insulation board to the first major surface of the insulation board. The sidewalls extending at an angle from 10 degrees to 20 degrees relative to each other.

What is claimed is: 
     
         1 . A kerfing apparatus configured to kerf duct liner insulation for a curvilinear duct, the kerfing apparatus comprising:
 at least one of a tapered router bit operably coupled to a CNC milling machine or a plurality of sets of stacked saw blades coupled to a rotatable shaft, wherein each set of stacked saw blades of the plurality of sets of stacked saw blades comprises an odd number of saw blades; and   wherein the at least one of the tapered router bit or the plurality of sets of stacked saw blades are configured to cut a plurality of rows of kerfs having v-shaped cross sectional configurations in an insulation board, the rows of kerfs configured to allow the insulation board to flex in a direction of the width of the insulation board such that insulation board is foldable into a curvilinear configuration to line the curvilinear duct when installed, and each of the kerfs of the plurality of rows of kerfs having sidewalls extending from a kerf base portion at or near a second major surface of the insulation board to a first major surface of the insulation board, the sidewalls extending at an angle from 10 degrees to 20 degrees relative to each other   
     
     
         2 . The kerfing apparatus of  claim 1  wherein each set of stacked saw blades comprises at least three saw blades including a first saw blade with second and third saw blades stacked on opposing sides of the first saw blade, wherein the first saw blade has a diameter greater than diameters of the second and third saw blades, and wherein diameters of the second and third saw blades are equal. 
     
     
         3 . The kerfing apparatus of  claim 1  wherein a smallest diameter saw blade of each set of the stacked saw blades is at least 1 inch greater in diameter than a diameter of the rotatable shaft 
     
     
         4 . The kerfing apparatus of  claim 1 , further comprising one or more spacers coupled to the rotatable shaft between at least two sets of stacked saw blades, wherein the curvilinear duct comprises a flat oval duct with flat portions and round portions, and wherein the one or more spacers have widths substantially equal to a width of the flat portions of the curvilinear duct. 
     
     
         5 . A method of kerfing duct liner insulation for a curvilinear duct, the method comprising:
 cutting a plurality of rows of kerfs having v-shaped cross sectional configurations in an insulation board, the rows of kerfs configured to allow the insulation board to flex in a direction of the width of the insulation board such that insulation board is foldable into a curvilinear configuration to line the curvilinear duct when installed, and each of the kerfs of the plurality of rows of kerfs having sidewalls extending from a kerf base portion at or near a second major surface of the insulation board to a first major surface of the insulation board, the sidewalls extending at an angle from 10 degrees to 20 degrees relative to each other.   
     
     
         6 . The method of kerfing duct liner insulation of  claim 5 , further comprising cutting the plurality of rows of kerfs with at least one tapered router bit operably coupled to a CNC milling machine. 
     
     
         7 . The method of kerfing duct liner insulation of  claim 5 , further comprising cutting the plurality of rows of kerfs with a corresponding plurality of sets of stacked saw blades coupled to a rotatable shaft, wherein each set of stacked saw blades of the plurality of sets of stacked saw blades comprises an odd number of saw blades. 
     
     
         8 . The method of kerfing duct liner insulation of  claim 7 , wherein each set of stacked saw blades comprises at least three saw blades including a first saw blade with second and third saw blades stacked on opposing sides of the first saw blade, wherein the first saw blade has a diameter greater than diameters of the second and third saw blades, and wherein diameters of the second and third saw blades are equal. 
     
     
         9 . The method of kerfing duct liner insulation of  claim 7 , wherein a smallest diameter saw blade of each set of the stacked saw blades is at least 1 inch greater in diameter than a diameter of the rotatable shaft. 
     
     
         10 . The method of kerfing duct liner insulation of  claim 5 , wherein cutting the plurality of rows of kerfs includes cutting a first row of kerfs such that first and second kerfed segments are formed on each side of the first row of kerfs, the first and second kerfed segments having trapezoidal cross sectional configurations, and wherein each of the first and second kerfed segments have an upper base width (a) and a lower base width (b). 
     
     
         11 . The method of kerfing duct liner insulation of  claim 10 , wherein one or more spacers are coupled to the rotatable shaft between at least two sets of stacked saw blades, the one or more spacers having a width substantially equal to the upper base width (a). 
     
     
         12 . The method of kerfing duct liner insulation of  claim 10 , wherein the lower base width (b) ranges from 0.6 inches to 1.6 inches. 
     
     
         13 . The method of kerfing duct liner insulation of  claim 10 , wherein the lower base width (b) ranges from 0.6 inches to 1.0 inches. 
     
     
         14 . The method of kerfing duct liner insulation of  claim 5 , wherein the sidewalls extend at an angle from 13 degrees to 17 degrees relative to each other. 
     
     
         15 . The method of kerfing duct liner insulation of  claim 5 , wherein the sidewalls extend at an angle from 14 degrees to 16 degrees relative to each other. 
     
     
         16 . The method of kerfing duct liner insulation of  claim 5 , wherein a depth of each of the kerfs does not penetrate the second major surface. 
     
     
         17 . The method of kerfing duct liner insulation of  claim 5 , wherein the curvilinear duct comprises a flat oval duct with flat portions and round portions and the insulation board comprises kerfed segments and unkerfed segments, the kerfed segments configured to line the round portions of the flat oval duct and the unkerfed segments configured to line flat portions of the flat oval duct when the insulation board is installed within the curvilinear duct. 
     
     
         18 . The method of kerfing duct liner insulation of  claim 17 , wherein one or more spacers are coupled to the rotatable shaft between at least two sets of stacked saw blades, the one or more spacers having a width substantially equal to a width of the flat portions of the curvilinear duct.