Correction of felt and dryer web tracking follows the 4-character principle: Move against for inward, move with for outward.

This principle means: at the felt/dryer web correction station, if the correction roll is moved against the running direction of the felt (dryer web), the felt (dryer web) will shift toward the operator. If the correction roll is moved in the same direction as the felt (dryer web) travel, the felt (dryer web) will shift away from the operator. This rule applies to top and bottom felts/dryer webs, regardless of the paper machine orientation, left-hand or right-hand machine, and whether the correction roll is on the drive side or operation side. As long as the correction roll is installed underneath the felt/dryer web, the positional relationship between felt/dryer web, correction roll and operator always obeys this principle.

Loose felt or dryer web will disable the tracking system and cause web deviation. Tension the felt/dryer web to its normal tension to restore proper operation.

If web tracking is caused by stuck correction guards due to accumulated pulp or dust, push and pull the guards following the above principle.

If tracking arises from a failed correction system, the system will no longer function. Immediately stop the felt/dryer web to avoid fabric damage.

With technological advances, traditional air-bag tracking systems have evolved into micro-motor tracking systems. Conventional air-bag correction guards are upgraded with ultrasonic position detection, keeping the fabric centered on the paper machine and rolls at all times. (See illustration for detailed working principle.)