Hard calendar is a machine usually installed at the PM line end before the reel. It is designed for both-sided smoothening of paper webs for production of Industrial and Cultural papers. At times, there is a steam box installed before the calendar which provides improved smoothness of the paper surface.

Design

The Hard calendar is standardly produced as multi or single-NIP press. Each NIP provides combination of two hard rolls, an oil-heated thermo roll & hard roll and an oil-heated thermo roll &
a swimming roll (Hard) with a camber control procedure according to the actually induced load.

Main parts

• Supporting structure
• Top roll
• Bottom Roll
• Swinging doctors
• Spreader roll
• Web guiding roll with bedding
• Pneumatic / Hydraulic Loading
• Heating station for Thermo roll
• Hydraulic Station for Swimming roll
• Drive for Both the Rolls

Supporting structure

Through its design this supporting structure, comprising particular stands made of structural steel, minimizes operating vibrations. Individual stands are mounted to each other by strengthened bolt connections and adapted to provide safety handling during on-site installation by a crane or other lifting devices. This supporting structure is designed to provide maximum machine rigidity both at standstill and running.

Top Roll:

Solid/Thermo roll, Fixed or floating with air bellow loading/ lifting Cast Iron roll with chilling depth of 10-12 mm

Bottom Roll:

Solid/ Swimming roll, Fixed or floating with Hydraulic upward loading/ lowering Cast Iron roll with chilling depth of 10-12 mm