Coated Stainless Steel Plate Heat Exchanger

VAU SAFE with anti-corrosion coating

Functionality of anti-corrosion coating

The anti corrosion coating of VAU SAFE Plate Heat Exchanger is based on silicon. It improves the mechanical and thermal stability of all components that come into contact with water. The coated heat exchanger is therefore free of non-ferrous metals - corrosion of brazing points is excluded - no metal ions are released from the stainless steel and it is self-cleaning since deposits can hardly adhere to the surface.

Coated stainless steel heat exchangers are quickly amortizing solution for modern heating systems. They are VDI 2035-compliant and, compared to copper-brazed heat exchangers, can cope with different filling water.

VAU SAFE is non-ferrous metal free and compliant with VDI 2035

Anti-corrosion stainless steel plate heat exchanger compared to copper brazed plate heat exchanger

copper brazed heat exchanger	VAU SAFE - stainless steel heat exchanger
due to corrosiveness of copper the following values should be observed
pH-value:                             7,5 to  9 hardness of water (°dH):  6 to 15 conductibility (µS/cm):    10 bis 500 Chloride (mg/l):                 < 300 (≤ 50 °C)                                              < 100 (≤ 75 °C)                                             > 100 °C not allowed	pH-value:                              < 6 to  9 hardness of water (°dH):   0 to > 15 conductibility (µS/cm):      10 to > 500 Chloride (mg/l)                     < 300                                                 > 100 °C not allowed

Advantages of coated stainless steel heat exchanger

Anti corrosion plate heat exchanger in modern heating systems

Modern hot water heating systems  become more and more compact and more efficient due to the increasing use of heat exchangers which means that filling water has to meet higher requirements. If this is not carefully conditioned, there is a risk of corrosion, calcification, contamination and deposits. The VDI 2035 guideline therefore requires the use of demineralized water. On the one hand it does not damage the boiler but it is fatal for uncoated stainless steel heat exchangers, because stainless steel can also be subject to corrosion (pitting, crevice corrosion, stress corrosion cracking).

Design of Brazed Heat Exchanger

Brazed Plate Heat Exchangers consist of serveral layers of stamped stainless steel plates (AISI 316L). The plates are joined to a plate pack which is brazed with 99.9% pure copper in our high vaccum furnace. Depending on the size the following connections are available: G ¾, G 1, G 1 ¼, G 2, G 2 ½, DN 50, DN 65.

Manufacturing of Brazed Plate Heat Exchangers

From stainless steel coil to the finished heat exchanger plate - the heart of our production for brazed plate heat exchangers are two fully automated production lines. Our hydraulic presses have a press force of 650 t and 2,000 t and have been individually adapted to the production of our brazed plate heat exchangers. In our state-of-the-art vacuum furnace the stamped plates are brazed with 99.9% copper. The result is a compact and pressure-resistant heat exchanger. Finally, the heat exchanger is coated using a CVD process (chemical vapor deposition). The anti-corrosion coating at 300°C enables the deposition of a thin silicon oxide layer on the entire and heating surface with an ultra-strong connection.

Applications