Air knife configured to improve rolling of paper product
Described herein are methods and systems for minimizing folding defects when rolling a paper product. The method comprises rotating a roll in a manner that draws a paper product toward the roll. The location of a pick-up point between the roll and the paper product is altered by influencing the air pressure experienced by the paper product. This may be accomplished by flowing air in one of several manners described in the specification.
1. A method of rolling a paper product onto a roll, comprising:
rotating the roll in a manner that draws the paper product toward the roll and rolls the paper product onto the roll; and
altering the location of a pick-up point between the roll and the paper product by influencing the air pressure experienced by the paper product by applying gas in a direction away from the paper product and the roll,
wherein the pick-up point is the location where a point on the paper product first contacts the roll.
2. The method of claim 1 , wherein gas is applied such that it prevents the paper product from folding as the paper product engages the roll.
3. A method for rolling a paper product onto a roll without creating roll defects, comprising:
suspending the paper product between the roll and a papermaking component;
applying a pressure difference to a portion of the suspended paper product by flowing air in a direction away from the suspended paper product that causes the portion to move toward the roll;
wherein the direction is away from both a pick-up point and the roll associated with the pick-up point, wherein the pick-up point is the location where a point on the paper product first contacts the roll; and
rolling the paper product onto the roll.
4. The method of claim 3 , wherein applying the pressure difference increases the tension in the portion of the suspended paper product.
5. The method of claim 3 , wherein the papermaking component comprises a slitter.
6. The method of claim 3 , wherein the papermaking component comprises a second roll.
7. The method of claim 3 , wherein the air is flowed in a direction orthogonal to the surface of the portion of the suspended paper product.
8. The method of claim 3 , wherein the air is flowed in a direction away from the pick-up point and at a vector angle less than 90 degrees and greater than 45 degrees to a plane of the portion of the suspended paper product.
9. The method of claim 3 , wherein the air is directed at a velocity sufficient to prevent the paper product from folding as the paper product engages the roll.
10. The method of claim 3 , wherein the air is directed at a volume sufficient to prevent the paper product from folding as the paper product engages the roll.
11. A paper-product rolling apparatus, comprising:
a web;
a roll configured to receive the web at a pick-up point and roll the web onto the roll, wherein the pick-up point is the location where a point on the web first contacts the roll;
a portion of the web located between the roll and a sequentially last papermaking component preceding the roll, and
an air knife configured to direct gas away from the roll and the entire portion of the web located between the roll and the sequentially last papermaking component preceding the roll, wherein the gas causes the portion of the web located between the roll and the sequentially last papermaking component preceding the roll to move toward the roll.
12. The apparatus of claim 11 , wherein the gas causes the portion of the web to move closer to a point on the surface of the roll that is closest to the portion of the web.
13. The apparatus of claim 11 , wherein the portion of the web closest to the air knife is suspended.
14. The apparatus of claim 11 , wherein the air knife is directed in a direction substantially orthogonal to the portion of the web that is not yet in contact with the roll.
15. The apparatus of claim 11 , wherein the air knife is directed at a vector angle less than 90 degrees and greater than 45 degrees to a plane of the portion of the web that is not yet in contact with the roll.
16. The apparatus of claim 11 , wherein the air knife is configured such that it biases the web close to a rotational axis of the roll.
17. The apparatus of claim 11 , wherein the air knife is configured such that it prevents the web from folding as it engages the roll.
18. The method of claim 1 , wherein the gas is applied in a direction away from a portion of the paper product that is not yet in contact with the roll.
19. The method of claim 3 , wherein the air is applied in a direction away from the portion of the suspended paper product.
20. The method of claim 1 , wherein the gas is directed in a direction substantially orthogonal to a portion of the paper product that is not yet in contact with the roll.
21. The method of claim 1 , wherein the gas is directed at a vector angle less than 90 degrees and greater than 45 degrees to a plane of a portion of the paper product that is not yet in contact with the roll.