Minimizing Shear on Paint
If you split flow streams in an e-coat paint recirculation line, what is the best method for manipulating flow rates that would minimize excessive shear on the paint?
Q. If you split flow streams in an e-coat paint recirculation line, what is the best method for manipulating flow rates that would minimize excessive shear on the paint? Would it be better to vary the pipe diameter or throttle with a butterfly valve?—M.A.
A. Fluid shearing refers to the development of external forces that strain or disrupt laminar flow. Thus, the pipe diameter increase will produce less shearing in the paint than installing a butterfly valve and throttling to decrease flow. Additionally, valves introduce significantly more pressure drop in the system than the roughness of the piping and require more energy to accomplish.
How one company is prospering by providing flexible e-coat capability to Nissan and other customers.
This paper is a peer-reviewed and edited version of a presentation delivered at NASF SUR/FIN 2012 in Las Vegas, Nev., on June 13, 2012.
How do you measure the surface area of a threaded fastener? How much coating would you put on it? How thick of a coating? What about non-threaded fasteners? The U.S. Department of Agriculture’s Forest Service, of all people, may have come up with the solution for those pondering how to coat sometimes-difficult small pieces using computer imaging and software to compute the area.