Metal Finishing Guide Book

2011-2012 Surface Finishing Guidebook

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Page 577 of 707

Rear view of large plating line. anode baskets, etc. The tank material must be chemically compatible—with the decision to either line the tank, or offer it without linings or inner coat- ings—for each solution, as well as each individual component. Each tank must be outfitted with a variety of compo- nents, based on just what the tank is supposed to accomplish. The soak cleaner would need either electric heaters or heating coils, tem- perature controllers, sensors, hi/lo level sensors, individual solenoids for city water or deionized water feed, agitation sparger (with agitation either provided by low-pressure, oil- free filtered air), or eductor/pump agitation. Other necessities: oil skim- mer, oil coalescer, pump and filter, and low-level shut off of the heater. The rinse tanks might require Automatic electroless nickel plating line. auto-fill city or deionized water sole- noids, air sparger manifolds, drain valves, overflow weirs, conductivity controllers, and possibly pump and filter, depending on particulate drug into them. Electro-cleaner tanks would also need a rectifier, anode/cathode bars, pump and filter, oil skimmer, heater or steam coil, solenoids for city and deionized water feed, etc. The process tanks would require similar components as the electro-cleaner, with an addition of rectifiers and other items, depending on the process. The rectifiers might be chosen to accommodate a variety of controls, such as constant current and/or constant voltage (pulsed, periodic reversed, or reverse pulsed; air, water, or convection cooled), and might include analog or digital amp/volt meters mounted remotely. The designer must decide just what type of heaters, agitation, cooling, fil- tration, circulation, rectification, and materials of construction, as well as what needs to be exhausted and which tanks need exhaust plenums. CFM requirements also need to be calculated for the entire line in order to size the air scrubber. If the plating tank happens to be an electroless nickel process, then the deci- sion must be made as to how to heat the tank. For example, would it be more prac- tical to use heaters, steam, or hot water coils? Or does it make more sense to make the tank a double-boiler tank heated with coils in the lining of the tank? CONSIDERATIONS WHEN DESIGNING A TANK There are many considerations when building the tanks, including size, quantity, and spacing of the girths around each tanks, as well as factoring in the weight capacity of each solution. All of this depends on specific gravity, operating tem- perature, and geographical location. On the West Coast, for example, you might require seismic calculations on the larger tanks. The plating lines might be either individual tanks sitting on a frame or mod- 576

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