In the cathodic electrodeposition process at the anode region continues to produce organic acids, if not promptly removed into the bath, the pH drop, affecting the stability of the process parameters pH value, the impact throwing power and film properties. Free acid bath to remove there are two ways: Adding non-neutralized or anodic and cathodic electrodeposition coating membrane system partially neutralized, commonly used anode diaphragm system method, especially on a large cathode electrophoresis equipment.
Method anode diaphragm system is enclosed in the anode box flushable anode, the anode box of a nonconductive material, open face (cover plate electrode toward the side to be coated, tubular electrode four weeks can be considered an open face) to contain the ion selective membrane. All requirements of the anode box sealed, leak test must be done prior to use, when to vote Anode box must be equipped with de-ionized water to prevent membrane rupture.
Anolyte system is composed of an anode membrane system, and from a very fluid circulation piping, pumps, tanks pole, conductivity and turbidity control device, ionized water supply piping and other components; anolyte circulation lines must be resistant to a pH of 2-5 organic acids stainless steel pipe or plastic tubing. Anolyte circulation amount per square meter of the effective electrode area of 6-10L / min, continue washing the anode, organic acid anions away. Each inlet pipe to install a pole cover meter to monitor anions. If the return pipe is extremely liquid plastic tube should be considered anolyte grounding.
Anolyte circulation system is to install a very fluid conductivity automatic control device. Provided extremely fluid conductivity is constant, when the deviation is 100us / cm, the automatic discharge anolyte, adding fresh deionized water, the conductivity sensor to be installed in the anode remote from the anolyte tank return position tube anolyte must be clear and transparent, cloudy illustrate the bath into the anolyte. When the bath into the anolyte, when the power will surface coated with paint inside anode diaphragm, making shade, flowing between the anodes affected, and affect the coating quality and production efficiency. Turbidity measuring electrode solution available visual method and turbidity meter. When they find anolyte turbid, should immediately stop pole pump, where possible, cut off the DC power supply. Found to have vulnerabilities anode cover it with the system partition, after shutdowns or quickly updated.