Surface and electroplating technology

Filtration of seal baths at an aluminum anodizing plant

seal bath purification in aluminum anodizing process

In aluminum anodizing plants, large quantities of items, including aluminum frames, are treated in various baths.

Due to the high volumes being treated, a large amount of suspended solids enters the so-called seal bath, which leads to high turbidity in the hot (nearly 100°C) deionized water bath. The seal bath serves to seal the oxide layer on the product.

Decrease in throughput due to frequent filter cloth changes.

Traditionally, disposable filters were installed in the filtration circuit to clean the bath. Although these filters provided very fine filtration, they led to a significant drop in flow rate within a few hours due to the rising differential pressure. As a result, the required cleaning performance could not be maintained, which led to quality issues.

High-precision filtration with high flow rates.

The use of fully automatic backwash filters effectively removes suspended solids from the seal bath through microfiltration or cake building filtration, even at high flow rates. At the same time, such a system operates without the need for extensive manual intervention or filter cloth changes. This saves a great deal of time and money and ensures a clean end product.

The solution: LENZING OptiFil

Fast and uniform formation of a filter layer with a high filter fineness.

< 10 µmFilter fineness
130 m³/hThroughput
< 0.05%backwash quantities

Process diagram of a LENZING OptiFil installation in the filtration process

LENZING OptiFil advantages

Benefits of using LENZING OptiFil.

High filter fineness

The use of precision fabrics ensures high product quality.

Efficient backwash

A patented backwash mechanism enables continuous operation for several months.

Cleaning performance

Consistently high circulation rates, combined with very fine filtration, result in high bath quality.

LENZING OptiFil

The LENZING OptiFil system is a reliable backwash filter for the finest filtration of industrial fluids and in water treatment. Its patented backwash system enables maximum process continuity with minimum backwash quantities.

High backwash efficiency (patented)

Filter fineness down to 1 μm

Very high throughput rates

Completely closed system

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