Caliper control system

A caliper control system for selectively changing the caliper of a web passing between rolls of a calender stack, said system comprising:

• first means for applying a heat transfer fluid to a surface of a first roll in the calender stack, said first means comprising a first distribution chamber for housing a supply of said heat transfer fluid, a first nozzle means for receiving said heat transfer fluid from said first distribution chamber and for applying said received heat transfer fluid to the surface of said first roll, said first nozzle means comprising a plate positioned adjacent said first roll, said plate including a plurality of sections and a pattern of holes comprising vertically arranged horizontal rows of three holes and vertically arranged horizontal rows of two holes positioned alternatively, each of said rows being centered about a vertical centerline of each nozzle plate section which enables said heat transfer fluid to pass through said plate to said first roll, and a first nozzle control means for regulating the flow of said heat transfer fluid from said first distribution chamber to said first nozzle means, said first nozzle control means being operable between a position allowing full flow of a said heat transfer fluid to a position preventing flow of said heat transfer fluid;
• a second means for applying a heat transfer to the surface of a second roll of the calender stack, said second means including a second distribution chamber for housing a supply of said heat transfer fluid, a second nozzle means for receiving said heat transfer fluid from said second distribution chamber and for applying said received heat transfer fluid to the surface of said second roll, said second nozzle means comprising a plate positioned adjacent said second roll, said plate including a plurality of sections and a pattern of holes comprising vertically arranged horizontal rows of three holes and vertically arranged horizontal rows of two holes positioned alternately, each of said rows being centered about a vertical centerline which enables said heat transfer fluid to pass through said plate to said second roll, and a second nozzle control means for regulating the flow of said heat transfer fluid from said second distribution chamber to said second nozzle means, said second nozzle control means being operable between a position allowing full flow of said heat transfer fluid to a position preventing flow of said heat transfer fluid;
• and
• first means for controlling the temperature of said first roll of the calender stack prior to applying said heat transfer fluid by said first means for applying a heat transfer fluid.