Use of centrifugal pumps for galvanic industrial treatments
Centrifugal pumps’ roleGalvanization is an operation performed to make some materials more resistant to corrosion. Nowadays, this process is very common but it has ancient origins: necessity to protect steel from rust brought people to develop zinc covering.
There are 3 main galvanic treatments types:
- Hot immersion
- Cold electrolytic deposition
- Fused zinc bath (galvanic bath)
After galvanization process, in case the zinc covering would be scratched, the internal structure (made of steel) would remain intact and only the external covering would be damaged. This is possible thank to the different electric potential of these two components. Zinc-coating, also named “electroplating” is used both for its protective and esthetic properties.
What is a galvanic treatment?Galvanic treatment consists in a series of operations, in parallel tanks, performed with liquid solutions containing metallic salts, basics, acids and specific additives. Temperature must be environmental or little higher.
Galvanic treatment is made up of three big steps:
- Preparation of surfaces to be treated through immersion, chemical degreasing or “electrolytic degreasing”
- Metallic covering: application of a metallic film (zinc, tin, copper, others)
- Conclusive treatment with “electrolytic passivation”
Use of centrifugal pumps for galvanic treatmentsPumps for galvanic industry are largely indicated for scrubbers, air depuration, pickling and galvanic processes (chromium plating, galvanization etc).
They are usually installed in plants that are specialized in galvanic baths, where aggressive acids are used to eliminate or add metallic material. A typical galvanic process consists in using a mixture of Hydrochloric Acid (HCL) and water (H2O) that is flushed with Zinc and Ammonium Chloride (ZnCl2-2NH4Cl). After that, galvanic deposition is performed.
Plastic centrifugal pumps are, therefore, required to move or empty galvanic baths: if compared to metallic pumps, plastic ones, do not suffer the aggressive effects of such chemical substances.
Magnetic drive pumps for galvanic industrySTN 70 magnetic drive centrifugal pump has been developed for applications proper of safe areas like galvanic industry, water treatments and scrubbers. STN 70 magnetic drive centrifugal pumps are now available in threaded version (DNa 80/ DNm50) and UNI PN16RF or ANSI 150 RF flanged (DNa 80/Dnm 65).
Do you want to know more about this topic? Feel free to contact CDR Pompe staff.