Internal and external epoxy coating
The majority of AVK products are as standard with internal and external epoxy coating according to DIN 30677-2 and GSK guidelines. The epoxy powder is applied on preheated components in a fluidised bed epoxy coating system. For selected products, such as small accessories or very big items, it is applied manually. The epoxy powder melts when in contact with the preheated components and cures when the components enter the cooling tunnel shortly after the coating process.
We control each batch of epoxy coated components to ensure a layer thickness of minimum 250 ¦Ì, a pore-free surface, high impact resistance and adequate curing. Please refer to our technical appendix. In addition to our own tests, the independent GSK authorities control the adhesion and cathodic disbonding of the epoxy coating according to their guidelines.
The GSK Quality Assurance Association for Heavy-Duty Corrosion Protection of Valves and Fittings with Powder Coating (GSK e.V.) is the international industry network for businesses that coat valves and fittings with epoxy powder. GSK awards the RAL-GZ 662 Quality Mark (G¨¹tezeichen) to companies who fulfil the strenuous quality-assurance requirements in accordance with the current Quality and Inspection Regulations. Click here for more information.
External PUR coating for galvanic corrosion prevention
An effective method to avoid galvanic corrosion is to keep the pipe system shielded to avoid that pipes and shut-off valves are in direct contact with the surrounding soil. AVK offers gate valves effectively protected with a PUR coating of minimum 1.5 mm according to EN 10290 type 2, class B. Every single PUR coated valve is pinhole tested by means of a holiday detector with an output voltage of 20,000V. Our approval criterion is zero pinholes.
Enamel of the highest quality
Enamel is a ceramic coating with durability and resistance properties like glass against aggressive fluids. It forms a chemical bond with the casting offering excellent protection against creeping corrosion. In 2017, the AVK Group took over EMK¡®s enamel facilities, and we now have in-house capacity to produce enamelled hydrants of our well-known high quality in addition to our long-running production of enamelled valves. With this expansion of our enamel facilities, we have full control of the supply chain.