Press nip formed by a deflection-controlled roll in conjunction with a temperature-controlled roll

A roll arrangement comprising at least two press rolls which rotate against each other to form a press nip, one of the two rolls being of a deflection-controllable design and the other press roll being constituted of a zone by zone temperature-controllable roll;

• the temperature-controllable press roll including:
• a tubular roll shell rotatable about an axial axis and having an interior surface, means for supporting the shell at the axial ends thereof, and a means for rotating the shell;
• a stationary core extending through the shell and having an exterior surface which faces the interior surface of the shell and means for supporting the core at its axial ends, the exterior diameter of the core being smaller than the interior diameter of the shell to define an annular space therebetween, which annular space has a radial thickness which changes in response to variations in the relative positions of the shell and the core arising from external forces applied to the shell;
• at least one peripheral seal, in the shape of a closed ring, located on and extending circumferentially around the core, the at least one seal dividing the annular space between the shell and the core into a plurality of annular chambers, the at least one seal having a contacting surface in sliding contact with the interior surface of the shell, the sliding contact making a non-pressure tight seal with the interior surface of the shell thereby to reduce frictional heat and wear normally occurring at the contacting surface of the peripheral seal;
• means for enabling the at least one seal to move into the surface of at least one of the shell and the core to accommodate variations in the radial thickness of the annular space whereby forces exerted on the seal by the shell or by the core will not be applied by the seal, respectively, to the core or to the shell;
• and
• a respective fluid supply line and a respective fluid return line coupled to each of the annular chambers for, respectively, supplying to and withdrawing from the annular chambers a temperature regulating fluid at about atmospheric pressure, whereby a local external diameter of the roll is controlled by regulating the temperature of the fluid in each annular chamber.

A roll arrangement comprising at least two press rolls which rotate against each other to form a press nip, one of the two rolls being of a deflection-controllable design and the other press roll being constituted of a zone by zone temperature-controllable roll;

• the temperature-controllable press roll including:
• a tubular roll shell rotatable about an axial axis and having an interior surface, means for supporting the shell at the axial ends thereof, and a means for rotating the shell;
• a stationary core extending through the shell and having an exterior surface which faces the interior surface of the shell and means for supporting the core at its axial ends, the exterior diameter of the core being smaller than the interior diameter of the shell to define an annular space therebetween, which annular space has a radial thickness which changes in response to variations in the relative positions of the shell and the core arising from external forces applied to the shell;
• at least one peripheral seal, in the shape of a closed ring, located on and extending circumferentially around the core, the at least one seal dividing the annular space between the shell and the core into a plurality of annular chambers, the at least one seal having a contacting surface in sliding contact with the interior surface of the shell, the sliding contact making a non-pressure tight seal with the interior surface of the shell therby to reduce frictional heat and wear normally occurring at the contacting surface of the peripheral seal;
• and
• fluid supply means for circulating a temperature regulating fluid which is supplied at about atmospheric pressure through the annular chambers, whereby a local external diameter of the roll is controlled by regulating the temperature of the fluid in each annular chamber.