1 Process

2.  Main feature: 

1) 6 teeth dipping star wheel is used. As the dipping time is a key influence on zinc coating thickness. Normal max. dipping time equals 3 cycling times. In order to get desirable dipping time without changing output, special operation mode can be offered.
2) 2 hot combustion fume recirculation fans are adopted in furnace system. The high speed hot air flow(of turbulent status) will be surrounding the kettle. The temperature evenness of kettle can be improved and it will result in a much better effect of heat conduction between hot fume and kettle surface. The temperature of furnace hearth will be lower and energy consumption will be reduced .
3) Dipping machine are equipped with 3 motorized press plates at inlet position. They are used for pressing inlet pipes quick immerging into zinc melt and forming a favorite air exhausting angle by adjusting strokes of 3 press plates individually. During dipping period if air is wrapped in pipe that will result zinc coating quality seriously.
4) Dipping machine is equipped with a motorized height adjusting system for big withdrawing magnetic rollers which will be removed with main frame of dipping machine by over crane during operation of dreg removing.
5）Long lancer plug inner wiping technology by using over heated steam is used for all sizes of pipe. Wiping head with many small holes to be inserted into pipe’s bore for wiping instead of traditional end nozzle whole section blowing. But the well de-burring of all pipe’s inner bore in ERW line is a must for taking this technology. The usage of this technology results in improvement on quality of inner wiping, saving steam consumption, significantly reducing noisy harm. The thing wiped away is not zinc powder ,but zinc particles which can be reused in kettle. The zinc consumption can be reduced for a great deal.
Over-heated steam will be used for inner wiping.
6) Passivation is carried out within a stainless box. A carefully design heating chamber for passive membrane drying will be followed.
7) Zinc powder collecting system will be canceled. The by-product of inner wiping is zinc
particle which can be re-used by collecting and directly putting it into kettle.
8) The usage of chain skid instead of tilting skid will be used within whole line which will result in noise reducing significantly.
9) No water rinsing technology with totally enclosed circulation flux regeneration system is adopted in this design pipe’s cleaning as follows:
a) Two water rinsing tanks following pickling are canceled and waste water exhausting will be thoroughly eliminated.
b) Fluxing will take over the pipes’ cleaning function. There are 2 fluxing tanks. One is dirty tank and the other one is a followed clean tank. These two tanks and a flux regenerating station are connected together by piping and pumps to form a closed circulating system. Dirty flux solution(Fe Cl2 <10g/L) is continually pumped (flow rate:3m3/hr) into regeneration station for treating. The treated super clean solution( FeCl 2<0.5g/L) is also continually pumped to clean tank. Then the solution in clean tank is continually pumped to dirty tank. So even the solution in dirty tank is always contaminated by pickled pipes but it will be continually clarified by clean solution from clean tank. All above is based on carefully calculation.
d) The adoption of this system will not only save water consumption and thoroughly eliminate contamination of waste water on environment, but the amount of Fe++ brought by flux on pipe’s surface and the zinc dreg generating in kettle is reduced great deal as well.
e) There are 2 chemical reactions carrying out in flux regeneration station:
2FeCl2 +2HCl+H2O2=>2FeCl3+2H2O (FeCl3---insoluble solid which will be
removed by press-filtering processing to form mud cake).
HCl+NH4OH=>NH4Cl+H2O (NH4Cl is one of the contents of flux).