Method for heating a roll and a heatable roll
AssigneeValmet Corporation
InventorsJuhani Niskanen, Jari Vahapesola
Life of this patent
Estimating the term…
Abstract
The invention relates to a method for heating a roll and a heatable roll for use in a paper machine, paper finishing machine, or equivalent. The roll is heated by a heating medium which is introduced into the roll interior through at least one of the ends of the roll. The heating medium acts upon the material of the roll mantle or the roll and is arranged to flow across the axial length of the roll. The heating medium is arranged to flow out of the roll through either one of the ends of the roll. The roll is provided with means by which the coefficient of heat transfer from the flowing heating medium to the material of the roll is increased in the flow direction of the heating medium.
Claims7
A heatable roll for a paper machine, paper finishing machine, or equivalent, comprising
- a roll mantle having a hollow interior, said roll further comprising a first end through which a heating medium is introduced into said interior of said roll mantle such that said roll mantle is heated, said heating medium being arranged to flow across an axial length of said roll mantle,
- a displacement piece arranged in said interior of said roll mantle such that an annular intermediate space is defined between said roll mantle and said displacement piece, said heating medium being circulated in said intermediate space from said first end of the roll to a second end of the roll opposite said first end, and
- means to increase the coefficient of heat transfer from the flowing heating medium to said roll mantle in a direction of flow of the heating medium through said roll such that the temperature of said roll mantle is substantially uniform across its axial length, said means comprising a roughened inner face of said roll mantle which defines said intermediate space, said inner face having an increasing degree of roughening in the flow direction of the heating medium.
A method for heating a roll of a paper machine, paper finishing machine, or equivalent, comprising
- introducing a heating medium into a hollow interior of a roll mantle of the roll such that the roll mantle is heated,
- arranging a displacement piece in the hollow interior of the roll mantle to form an annular intermediate space between an inner face of the roll mantle and the displacement piece in which the heating medium flows, and
- roughening the inner face of the roll mantle and increasing the degree of the roughening of the inner face in the flow direction of the heating medium to increase the coefficient of heat transfer from the flowing heating medium to the roll mantle in a direction of flow of the heating medium through the roll such that the temperature of the roll mantle is substantially uniform across its axial length.
Dependencies are inferred from the claim text.