| 摘要 |
The concentration of solvent in a fluid including solvent and aqueous components is gradually decreased while the fluid is in contact with the electronic assemblies to be cleaned. An apparatus for cleaning electronic assemblies has a fluid supply tank containing emulsifiable fluids and a wash chamber containing the electronic assemblies. A fluid circuit includes a supply pump and a supply line for providing fluid from the tank to the chamber, and a valve drain line for returning fluid to the chamber to the pump. A sprayer within the chamber uses a separate sprayer pump for spraying fluid collected within the chamber onto the assemblies. The supply pump is connected to the supply tank at an intermediate level such that it initially draws off all of the uppermost, lightest fluid layer, and only a portion of the lower fluid. Consequently, the initial wash includes a higher solvent concentration than in later wash stages, when all fluid is uniformly mixed.
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