ROTARY SEAL METHOD OF STRIP SUCH AS STEEL SHEET

PROBLEM TO BE SOLVED: To provide a rotary sealing method capable of preventing generation of surface flaws or wrinkles of a strip while leakage of the treatment solution is prevented to a maximum. SOLUTION: In an equipment in which a strip S is passed between a pair of seal rolls 2, 3 provided on at least either of the inlet side and the outlet side of a treatment tank 1 to continuously pass the strip S, the gap between the circumferential surfaces of a pair of sealing rolls 2, 3 is set to be larger than the thickness of the strip by 0.3-2mm to realize the non-contact relationship between the strip surface and the circumferential surfaces of the sealing rolls, the treatment solution is squeezed by the space which is formed by the seal rolls and gradually reduced in the advancing direction of the strip, and a thin film layer made by the treatment solution in the treatment tank is formed between the strip surface and the circumferential surfaces of the sealing rolls to generate the sealing force to the treatment solution. The seal rolls are of the rotary type, and generation of surface flaws is controlled even when the strip is brought into contact with the sealing rolls by matching the rotational direction of the sealing rolls with the strip passing direction, and agreeing the peripheral speed of the sealing rolls with the strip passing speed to set the relative speed to be zero.