Method and apparatus for processing compressible material

In a method for processing compressible insulation material of mineral fibers of the type in which the insulation material is passed through a folding shoe which guides the insulation material from a flat condition to a shape having a generally circular cross section, the improvement comprising:

• initially folding the insulation material around a cylindrical mandrel positioned within said folding shoe and compressing the insulation material at the bottom of the mandrel;
• subsequently compressing the portions of insulation material at the sides of said mandrel, thereby causing some of the insulation material to migrate upwardly toward a position above said mandrel resulting in a higher concentration of the insulation material above said mandrel;
• and, thereafter,
• compressing the insulation material at the top of said mandrel so that the density of the insulation material at the top of said mandrel is greater than that at the sides and bottom of said mandrel.

In apparatus for guiding compressible strip material into a cylindrical shape of the type in which the strip material is passed lengthwise through a folding shoe and wrapped around a mandrel positioned within said folding shoe, the improvement comprising:

• the inlet portion of said folding shoe being adapted to compress the portion of the strip material along the centerline thereof;
• the intermediate portion of said folding shoe being adapted to compress the portions of the strip material intermediate said centerline and the side edges of the strip material to cause an upward migration of the intermediate and side edge portions resulting in a heavier concentration of the strip material above the top of the mandrel;
• and,
• the outlet portion of said folding shoe being adapted to compress the side edge portions of the strip material so that the density of the side edge portion is greater than the density of the center and intermediate portions of the strip material.

In apparatus for processing compressible insulation material of mineral fibers of the type in which the insulation material is passed lengthwise through a folding shoe, position in which is a cylindrical mandrel, the improvement comprising:

• the inlet portion of said folding shoe being adapted to fold the insulation material around said mandrel and to compress the insulation material at the bottom of said mandrel;
• the intermediate portion of said folding shoe being adapted to compress the portions of the insulation material at the sides of said mandrel and to cause some of the insulation material at the sides of the mandrel to migrate upwardly toward a position above said mandrel resulting in a heavier concentration of the strip material above the top of the mandrel;
• and
• the outlet portion of said folding shoe being adapted to compress the insulation material at the top of said mandrel so that the density of the insulation material at the top of the mandrel is greater than at the sides and bottom of the mandrel.