Method and apparatus for the rapid consolidation and/or drying of moist porous webs
AssigneePulp and Paper Research Institute of Canada
InventorDonald G. Sparkes
Life of this patent
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Abstract
There is taught a method and apparatus for a drying of a continuous moist web such as paper wherein the web is passed through a nip formed of two moving surfaces, one of these surfaces being a relatively impermeable material heated to a temperature of at least 120.degree. C., the other surface being formed of a relatively porous material and being maintained at a temperature below 100.degree. C., while maintaining a pressure on the moist web sufficient to prevent blowoff.
Claims5
A method for the drying of a moist, porous moving web comprising the steps of
- forming a nip between first and second moving surfaces, the first moving surface comprising a rotating cylinder formed of a relatively hard impermeable material, the second moving surface comprising a moving permeable felt supporting the moist moving web on a second rotating cylinder,
- maintaining a pressure at said nip,
- passing the moist moving web between the first and second moving surfaces,
- heating said first moving surface before the nip to a temperature in excess of 120.degree. C. by induction heating using alternating current induction coils at a frequency of at least one kilohertz, and maintaining the second moving surface at a temperature below 100.degree. C.
An apparatus suitable for the drying of a continuous moist web of paper, comprising first and second moving surfaces, a nip formed between said first and second moving surfaces, the first moving surface comprising a rotating cylinder formed of a relatively hard impermeable material, the second moving surface comprising a moving permeable felt supporting the moist web of paper on a second rotating cylinder, means for maintaining pressure at said nip, induction heating means for heating said first moving surface before the nip to a temperature of at least 120.degree. C. using alternating current induction coils at a frequency of at least one kilohertz, and means for maintaining said second moving surface at a temperature below 100.degree. C.
Dependencies are inferred from the claim text.