<P><FONT face=Verdana> contemporary besmear installs technical development to must accord with economic benefits to show high, efficient, ecological balance, 4 principles such as managing the sources of energy. And outfit of besmear of pulverous and electrostatic surface is had just about high grade, efficient low cost, the advantage such as free from contamination. Accordingly, this new technology is in " 75 " during by national classics appoint one of projects of new science and technology that study for 70 keys surely and popularize. When is popularizing this new technology, the benefit after we besmear to pulverous and electrostatic surface the fundamental that installs technology reachs his to apply above all (economic benefits, social benefit) make one simple introduction.  </FONT></P>
<P><FONT face=Verdana>   one, besmear of pulverous and electrostatic surface installs a principle:  </FONT></P>
<P><FONT face=Verdana> Electrostatic spray should have   powder above all the maximum pressure that generates dc maximum pressure is electrostatic generator, with the spray gun that comes out pulverous eject. Can below general reason condition, workpiece ground connection, spray gun needle receives negative high pressure, negative high pressure is high pressure electrostatic generator furnishs. When spray gun most advanced approach work, produce corona discharge phenomenon, powder comes out from eject of spray gun mouth, through corona discharge took negative electric charge. The pulverous particle that this takes negative electric charge is below electrostatic force and the effect that reduce air current arrive at workpiece surface, electrostatic appeal is had between the negative electric charge of the other part of pulverous particle and workpiece, make pulverous particle adsorptive in workpiece apparently, down to beats workpiece, powder and fall off not easily also with bead. Because pulverous particle has taller resistance, the negative electric charge that takes on reason particle leaks not easily, make powder quite can long thereby adsorption is in workpiece surface, but atomic resistor is had jumped over not quite more, resistance is too great, negative electric charge goes up with respect to not easy belt on pulverous particle, cause absorption affinity small, general powder compares resistor atomicly to be in 102 - 103 Ω are advisable. Pass electrostatic spray, can make look of pulverous and even ground gets together at workpiece surface, because take,exclusive power is had between the particle of negative electric charge again. This kind of repulsion conduces to the action of dispersive particle, it is certain that the pulverous bead layer of workpiece surface adsorption is achieved thick when, won't add again thick. Assured to become thereby after workpiece solidify, exterior film is even. Additional, pulverous electrified volume also is not larger better. Because electrified amount is larger, although absorption affinity is big, but repellent power is great also, reason powder is electrified also want proper, it is commonly on the rate that 107 libraries ∕ captures Q ＝ , the tension that when spray is operated, uses is commonly 50 - 80KV, discharge quantity is 100 μ A the following, spray gun is most advanced the distance with workpiece 10 - 20 ㎝ are advisable. Workpiece does not heat, namely when cold in season, coating ply is commonly 50 - 100 micron. If workpiece undertakes heating before spray, the in workpiece surface atomic resistor when spray decreases, the electrified quantity of atomic layer decreases, can make film ply increases thereby, be versed in so   when hot gush, film ply can amount to 500 micron. Cave in workpiece place, as a result of the action of electrostatic screen, use voltage is taller, electrostatic screen effect is bigger, must reduce voltage to undertake spray at this moment.  </FONT></P>
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