Apparatus for hot dip galvanizing

An apparatus for hot-dip galvanizing, comprising:

• a plating tank which holds a molten metal;
• a separation wall located in the plating tank to divide the plating tank into a plating zone where a steel strip is subjected to hot-dip plating, and a dross removing zone where dross in the molten metal bath is removed;
• the dross removing zone comprising a first dross removing zone and a second dross removing zone;
• a first mechanical pump which transfers the molten metal bath from the plating zone to the first dross removing zone;
• a second mechanical pump which transfers the molten metal bath from the plating zone to the second dross removing zone;
• a first weir located to the separation wall to transfer a supernatant bath of the molten metal bath after removal of the dross in the first dross removing zone to the plating zone;
• and
• a second weir located to the separation plate to transfer a supernatant bath of the molten metal bath after removal of the dross in the second dross removing zone to the plating zone.

An apparatus for hot-dip galvanizing, comprising:

• a snout through which a steel strip travels;
• a plating vessel which holds a molten metal, said plating vessel having a sink roll to guide the steel strip which travels through the snout;
• a plating zone to conduct hot-dip galvanizing by immersion of the steel strip thereinto and a dross removing zone to remove dross from a molten metal bath, said plating zone and said dross removing zone being formed by locating a shielding member to shield a gap formed between a lower portion of the snout beneath the steel strip and an upper portion of a side wall of the plating tank;
• and
• a mechanical pump to discharge the molten metal bath from the plating zone to the dross removing zone and also to recycle the molten metal bath from the dross removing zone to the plating zone.

An apparatus for hot-dip galvanizing, comprising:

• a plating bath tank which holds a hot-dip galvanizing bath containing aluminum at a content of 0.05 wt. % or more;
• a snout through which a steel strip immersed in the plating bath tank travels;
• a plating tank wherein plating is conducted and a dross removing tank wherein dross is separated by sedimentation of the dross, both of the plating tank and the dross removing tank are formed by locating a separation wall in the plating bath tank;
• a snout cleaning device which connects the plating tank and the dross removing tank at directly below the snout and at a part of exit of the steel strip so that a connecting passage has a hydraulic diameter of 0.1 meter or more, the hydraulic diameter being defined by a formula given below, and so that the bath levels of the plating tank and the dross removing tank become equal to each other, the snort cleaning device having a pump to suck the plating bath in the snout from both longitudinal edges of the snout to discharge the sucked bath to a portion where the steel strip does not travel, thus cleaning a plating bath surface in the snout, and to circulate the plating bath between the plating tank and the dross removing tank;
• wherein the hydraulic diameter is defined as follows:
• hydraulic diameter={(cross sectional area of flow passage)/(wet length of flow passage)}×4.