Membranes 隔膜
Membranes are selective barriers which allow particles or molecules of one kind to pass and exclude all others. This condition can be achieved by using size-exclusion membranes or by using anolyte (electrodialysis) membranes which operate in the presence of dense electric charges.
隔膜可以有选择性的允许一种粒子或一种分子通过，而挡住其它物质。使用特定尺寸的隔膜或使用在高电荷密度下运行的阳极液（电渗析）隔膜， 可以达到这种状况。
Two types of membranes are found in all electrocoat tanks: anolyte and ultrafilter membranes. The purpose of the anolyte membrane is to remove acid buildup which occurs when cationic resin is deposited upon a part. The purpose of the ultrafilter system is twofold:
在所有的电泳槽中泳用到两种隔膜， 阳极膜和超滤膜。阳极膜的作用是除去阳离子树脂电泳到工件时产生的酸积聚。超滤膜的作用有两个：
To provide a rinse solution to achieve the closed loop system, which will remove dragout, enabling high paint usage and resulting in clean coated products.
为闭路冲洗系统提供清洗液，冲洗掉由电泳槽中带出的浮漆，提高油漆利用率， 从而得到清洁的产品。
To remove water-soluble contaminants which might enter the tank through phosphate carry-in.
除去可能从磷化带入电泳槽中的水溶性污染物。
1.1.1. Ultrafilter Membranes
超滤膜
Ultrafilter membranes work on the principle of size exclusion. Dissolved molecules and particles are sorted out according to whether or not they are small enough to pass through the pores of the membrane.
超滤膜是利用筛分原理工作藉此把所需的并能通过隔膜微孔的物质与不能通过的溶解分子颗粒分开。
In normal particulate filtration, liquid is forced under pressure through a porous medium. In ultrafiltration, similarly, liquid is forced under pressure through a porous medium. However, the pores are 1,000 times smaller. In fact, the membranes are so small that even some bacteria are unable to pass through.
一般的过滤是在压力作用下强行是液体通过多孔介质， 同样，在超滤中， 也实在压力下强行通过多孔介质。然而，这孔径要小1，000倍， 实际上， 隔膜的孔径小得连有些细菌都不能通过。
The ultrafilter membrane will pass water, acid, some solvent, low-molecular- weight fractions of resin, and contaminating ions. When the bath is operating within the proper conductivity parameters, the ultrafiltrate is used to achieve the closed-loop rinse system. High conductivity is an indication of ion contamination. When this condition occurs, the ultrafiltrate is sent to drain, and deionized water is added to the rinses.
超滤膜可以通过水，酸，某些溶剂， 低分子量树脂及杂质离子。当电泳槽在正常的电导率参数内运行时，使用超滤供封闭循环的清洗系统， 电导率高， 表明有离子污染， 当发生这样情况时， 要排放超滤液， 加去离子水供清洗用。
Two forces oppose the production of ultrafiltrate: osmotic force and concentration polarization force:
阻碍超滤液的生成有两种力，渗透力和浓差极化力。
Osmotic force is the tendency of a solvent to equalize concentration throughout its volume. This force is overcome by applying pressure to the paint passing through the ultrafilter.
渗透力是一个溶剂在其容积内浓度不断平衡的趋势。 这个力靠施加压力使油漆通过超滤装置来克服。
Concentration polarization force is the tendency for molecules to build up or concentrate at the membrane surface. Again, pressure may be applied, but a rapid movement of paint across the membrane is also important. At least four types of ultrafilters are available:
浓差极化力是分子在膜表面堆积或浓缩的趋势。仍然是要施加压力， 而且使油漆快速通过膜表面， 来减少这个浓差极化力。超滤装置有四种类型中， 后面两种最普及。
- Plate and frame
板框式
- Spiral wound
螺旋式
- Open tube
开管式
- Hollow fiber
中空纤维式
1.1.2. Anolyte Membranes
阳极液隔膜
These membranes work on the principle of electrodialysis. Unlike ultrafilters, they do not require pressure. The energy required is supplied by an electric field across the membrane. This membrane has a dense concentration of fixed charges and contains fine pores, permitting it to be selectively permeable to ions bearing the correct charge.
这类隔膜以电渗析原理工作， 与超滤器不同，他们不需要压力。 由穿过隔膜的两侧提供所需的能量， 隔膜带有稠密的电荷密度及微孔。能有选择的允许带相应电荷的离子透过。
When the resin deposits at the cathode, the counter ion which keeps the resin in solution accumulates. Since the counter ion is acidic, its buildup reduces the pH. However, the anolyte membrane permits the acid, but not the resin, to pass. Thus, the excess acid is removed, and the target pH of the bath is maintained.
当树脂在阴极上沉淀时，平衡树脂的离子在溶液中累积，由于这些平衡离子是酸性的，它的累积使pH下降。然而，阳极液隔膜仅允许 酸通过， 但不允许 树脂通过。 这样，除去多余的酸，来维持槽液的正常pH值。
Section Summary
本节摘要
Summary: Resin and pigment are deposited at the cathode in the cathodic system of electrocoating. This method is superior to the anodic method because of the greatly enhanced corrosion protection.
要点：在阴极电泳系统中，树脂和颜料沉积在阴极上， 因此大大地提高了防腐蚀性，这个方法比阳极法优越。
The four reactions that occur as a car body is being coated are listed below. The key word from the definition follows in parentheses.
下面列出了涂装一台车身时发生的四个反应。定义的关键字写在括号中。
1 Electrolysis (decomposition)
电解（分解）
2 Electrophoresis (migration)
电泳（泳动，迁移）
3 Electrodeposition (precipitation)
电沉积（析出）
4 Electroendosmosis (dehydration)
电渗（脱水）
