Patent ID: 9476128
Filing Date: 2016-10-25
CPC Classification: B08B,B21B,C23G

Claim Text:
1. A method of cleaning a steel sheet, wherein said steel sheet is running in a running direction, said method of cleaning said steel sheet is conducted by using a continuous cleaning system characterized in that a cleaning unit consists of a cleaning solution feeder and a rinse unit, said method of cleaning said steel sheet comprising spraying a cleaning solution activated by megasonic waves of a frequency of 0.8 MHz to 3 MHz to a surface of said steel sheet at a feed angle inclined in a direction opposite to the running direction by 10-52° with respect to a line perpendicular to the surface of the steel sheet and spraying said surface in the running direction such that said cleaning solution with said megasonic waves strikes said surface, flows over said surface in the running direction and is received in a cleaning solution receiving container, thereby cleaning said steel sheet, wherein a running speed of the steel sheet is in the range of 20 to 300 m/min and a discharge rate of the cleaning solution is in the range of 200 to 1100 L/min wherein the steel sheet is not immersed in the cleaning solution, and wherein a feed rate of the cleaning solution is, per unit area of the steel sheet, in a range of 1 L/m wherein a storage part of the cleaning solution feeder, an outlet of the cleaning solution feeder and a cavity part of the cleaning solution feeder in which a megasonic generator to generate the megasonic waves is housed are inclined at the feed angle of the cleaning solution, and wherein the cavity part is flushed with dried air or inert gas to prevent an entry of corrosion products.