Process control system for corrugators

A method of reducing warp in blanks being made from a double-face corrugated paperboard web issuing from a corrugator machine comprising the steps of:

• observing the kind and amount of warp in said blanks and, in response to observing warp in said blanks, selectively changing at least one of:
• a. the heating time of said double-face web advancing through said corrugator machine;
• b. the relative amount of heat between a single-face web and a double-face liner forming said double-face web;
• and
• c. the relative amount of moisture between said single-face web and said double-face liner
• to reduce said warp;
• and, following said selective changing,
• automatically maintaining substantially constant said heat time of said double-face webs and the relative amount of heat and moisture in said single-face web and said double-face liner at selected running speeds of said corrugator machine.

Apparatus for improving the quality of blanks made from a double-face corrugated paperboard web issuing from a corrugator machine, said machine including in combination:

• first heating means for heating said double-face web for a substantially constant time;
• second heating means for applying a substantially constant amount of heat to a single-face web and to a double-face liner forming said double-face web;
• moisture means for applying a substantially constant amount of moisture to said single-face web and said double-face liner;
• and
• control means responsive to the speed of said corrugator machine for controlling said first heating means, said second heating means, and said moisture means to automatically maintain said heating time, said amount of heat, and said amount of moisture substantially constant throughout the range of operating speeds of said corrugator machine.