OPERATING METHOD FOR ULTRAFILTRATION SYSTEM IN ELECTRODEPOSITION PAINTING

摘要

PURPOSE:To extend the life of the membrane of an ultrafiltration module and maintain the module at high performance for a long period of time by suspending the paint circulation of returning the paint concd. in the module to an electrodeposition paint tank for a prescribed time and washing the surfaces of the module membrane with the filtrate injcted into the module. CONSTITUTION:The paint in an electrodeposition paint tank 1 is forcibly fed with a pump P1 to a module 2 through a fully opened circulation piping 3. After it is concd. in the module, it is returned into the tank 1. The filtrate produced by filtration in the module is once stored in a tank 4, from which it is pumped P2 to a washing line 6. If solenoid valves AV1, AV2 are closed and opened when stopping the operation of the electrodeposition, the filtrate in the tank 4 is injected with the pump P1 into the module 2 and the paint therein is forced out into the tank 1. In this case, the gel layers stuck on the surfaces of the module membrane are washed and are forced out into the tank 1. When the washing of the membrane is completed, the inside of the module 2 is completely substituted with the filtrate. The valves AV2, AV3 are closed, and the membrane is held in a pressure-free state until the electrodeposition operation is resumed.