Paper Stock to the Machine

Modifications of Pulp before Machine

Outside of HD7 (Old Corrugated Board Storage)

From the High Density Storage Tanks, pulp must be diluted, refined, and blended before entering the paper machine.

Refining

During refining the primary wall the fibers in pulp is removed which creates fines. Water penetrates the cell wall which is known as swelling. The intra-fiber bonds break and are replaced by hydrogen bonds (hydration). This causes fibers to become more flexible, have external fibrillation and foliation, and get shortened.

While fibrillation can greatly increase the strength of the the paper made, pulp drain-ability is greatly reduced.

Variables That Affect Refining

1. Species of fiber
2. Pulping method
3. Fiber length and coarseness
4. Earlywood/latewood ratio
5. Bar size and shape
6. Refiner Speed
7. Temperature
8. pH
9. Consistency
10. Refiner Intensity

Toledo uses disc refiners. For example, from the HD5 storage tank containing kraft pulp, a line goes to the #3 Refiner chest, the Secondary Refiner Chest, the Saveall, the Pre-refiner chest, and the Blend Chest for PM1. From refiner chests, pulp will be sent to the refiners, and then the machine chest which goes to the refiner pump.

At the blend chest, different furnish mixes of kraft, Modified Kraft Process Pulp (Hardwood), Double Lined Kraft, and water are mixed specifically for each machine and grade.

Finally from the blend chest, the pulp will go to the fan pump which now enters the wet end of the paper machines!