Maintain the bath quality with good water quality
The pretreatment system performs cleaning, rinsing and preparation of the product surface. The purpose of a pretreatment system is to ensure corrosion protection, optimal coating adhesion, superior optics, and durable surfaces. All these factors depend on proper rinse water quality for achieving excellent product finish.
Waterworks > Adsorption > Softening > Reverse osmosis
Treatment for optimal make-up water
- Inlet water treatment: Adsorption by pressure filter or activated carbon filter for the removal of precipitation, suspended solids and free chlorine.
- Removal of hardness: Softening for hardness removal to prevent membrane scaling
- 99% removal of inorganic materials and microorganisms: Reverse osmosis (RO) unit producing demineralized water with a conductivity between 10 and 15 μS/cm.
Demineralized make-up water
In all water-based pretreatment systems there is a need to add fresh make-up water due to evaporation, drag-over, renewal of the water in the different baths, etc. If available, the distillate from a vacuum distillation system can serve as a feedwater source.
The requirement for the make-up water is demineralized water with low salt and silica content. But to keep a continuous, smooth system operation it is essential to treat the inlet water. The purpose of pretreatment is to prevent clogging of the membranes with precipitations and suspended solids and to remove free chlorine
Recirculating rinse water
Recirculation over ion exchange resin reduces the amount of fresh make-up water needed. This is a sustainable solution to lower water consumption and even reduce cost.
Water for reuse is treated in several steps:
- Filtration of mechanical impurities
- Adsorption of organic substances
- Demineralization with ion exchange
Important factors to consider for recirculation systems
All-in-one reverse osmosis unit with pre-treatment
The all-in-one CU:RO compact unit is an excellent make-up water solution that provides softening and reverse osmosis with only a small footprint and easy installation.
Water treatment designed for the surface treatment industry
We have collected all you need to know about optimum water treatment for surface treatment. Think water first if you want quality products - every time!
Explore related technical references of the surface pretreatment solutions
DI rinse water for production of high-end audio products
The customer is developing and manufacturing high-end audio products. To support a growing demand of modern aluminum cabinets, the customer has implemented a new anodizing surface treatment line. For this purpose, demineralised rinse water of high purity is needed. The result is an exclusive surface look and top product quality.
Grundfos has supplied and installed a new water treatment solution for the production of demineralised water. Due to lack of space, a compact RO unit with a small footprint was selected. After the RO unit the water is further polished in a mixed-bed unit in order to reach the high water quality. The mixed-bed unit is for off-site regeneration, supporting the space issue as well as a concern for a complete chemical free solution.
DI circulation system for pre-treatment of aluminium cans
Increasing operational safety and saving water was pivotal for this global supplier of aluminium cans, when a second water treatment plant was added to the production.
The water treatment solution consists of mechanical filtration, in which undissolved impurities are removed from the circulating rinse water. The water is then desalinated with a DI system consisting of a cation and an anion filter supplied by a pressure-controlled pumping station (2 x 100%).
The DI system is operating in triplex mode, with two units in operation and the third in regeneration or standby. This ensures no operational downtime. Because of the increased water temperature, the entire system is designed with PP piping.
The second water treatment plant initially serves as redundancy, but over time it could take over the full capacity.
Rinse water for surface treatment in the automotive industry
The customer is a leading supplier of sophisticated forming technology in body construction for premium cars. In their paint shop they use cathodic electrodeposition, also known as cathodic dip coating or cataphoretic painting, which is a high-quality, economical coating process for all submersible metal parts. For this process they require a large volume of rinse water of high quality.
After more than 20 years of operation it was necessary to repair some broken parts and exchange the control of the existing demineralisers, but based on a profitability analysis, the customer decided to replace the complete plant with new and modern technology offering many valuable benefits to the operation.
Technically speaking, the old demineralizers with co-current regeneration was replaced with UPCORE technology (UPflow COuntercurrent REgeration) because of the following features:
The system is self-cleaning, thus ensuring a constant, low pressure loss and trouble-free operation
The optimised utilisation of the regeneration chemicals leads to reduced operating costs.
How can we help you?
Whether you’re looking to buy a product or simply seeking advice from a Grundfos expert, we are more than happy to help you get the most out of your water treatment solution! Feel free to get in touch if you need support.