Valmet Paper Machinery Inc.

Hannu Maa

Juhani Niskanen

Harri Kuosa

Ari Lassila

Pentti Hyytinen

A supercalender comprises a stationary variable-crown upper roll (1), a floating variable-crown lower roll (2), several intermediate rolls (3,4) between the upper roll (1) and the lower roll (2), and a hydraulic control system. The upper roll (1) has a roll mantle (12) that is supported on the roll shaft (11) by hydrostatic loading elements (13) acting in the direction of compression and by end bearings at the ends of the roll mantle, which bearings prevent displacement of the mantle (12) ends in the radial direction relative to the shaft (11) of the upper roll. The lower roll (2) has a roll mantle (22) that is supported on the roll shaft (21) adjustably in the direction of compression by means of hydrostatic loading elements (23). Position detectors (23,31) are provided at the ends of the shaft of at least one roll. The control system is arranged to regulate the positions of the rolls (1 to 4) in the system of rolls and to balance the forces effective in the supercalender in response to measurement signals received from the position detectors (27,31) and from the hydrostatic loading elements (23) of at least the lower roll.

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Jarvenpaa, Finland

Hannu Maa