US 12,168,826 B2
Plating weight control device and control method
Ilhwan Noh, Pohang-si (KR); Taein Jang, Pohang-si (KR); and Won-Ho Lee, Pohang-si (KR)
Assigned to POSCO CO., LTD, Pohang-si (KR)
Appl. No. 17/278,141
Filed by POSCO, Pohang-si (KR)
PCT Filed Sep. 20, 2019, PCT No. PCT/KR2019/012215
§ 371(c)(1), (2) Date Apr. 27, 2021,
PCT Pub. No. WO2020/060273, PCT Pub. Date Mar. 26, 2020.
Claims priority of application No. 10-2018-0114320 (KR), filed on Sep. 21, 2018.
Prior Publication US 2021/0348258 A1, Nov. 11, 2021
Int. Cl. C23C 2/00 (2006.01); C23C 2/16 (2006.01); C23C 2/26 (2006.01); C23C 2/40 (2006.01)
CPC C23C 2/16 (2013.01) [C23C 2/00344 (2022.08); C23C 2/26 (2013.01); C23C 2/40 (2013.01); C23C 2/51 (2022.08)] 8 Claims
OG exemplary drawing
 
1. An apparatus for controlling coating weight of a steel sheet by using two air knives, the apparatus comprising:
an air knife condition derivation unit configured to derive a first air knife gap and a final air knife pressure for target coating weight, and derive a second air knife gap for achieving the target coating weight at a current air knife pressure;
an air knife pressure response compensation unit configured to determine a final air knife gap according to a gap compensation amount that is a difference between the second air knife gap and the first air knife gap and a gap compensation ratio based on an air knife pressure variation amount for a control period; and
a wiping part configured to receive the final air knife pressure from the air knife condition derivation unit and the final air knife gap from the air knife gap compensation unit and control the two air knives according to the final air knife pressure and the final air knife gap so that the target coating weight is achieved,
wherein the control period is a period for updating an air knife condition for the target coating weight,
wherein, when the control period is longer than the pressure response time period, the air knife pressure response compensation unit sets the gap compensation ratio to zero,
wherein, when the control period is equal to or shorter than a pressure response time period, the air knife gap compensation unit further configured to calculate the gap compensation ratio based on the air knife pressure variation amount for the control period and a value obtained by dividing the control period by the pressure response time period, multiply the gap compensation amount and the gap compensation ratio, and determine the final air knife gap by adding the value obtained by the multiplication to the first air knife gap, and
wherein the pressure response time period is the time period for which the current air knife pressure reaches the final air knife pressure.