The inflated heat exchanger plates of Dimple-t are manufactured from two sheets either of the same wall thickness (D-type or double embossed) or of different wall thickness (S-type or single embossed) by laser- or resistance welding. Typically we work with 1 + 1 mm or 1,2 + 1,2 mm for the D-type. The S-type plates consist of a thick plate and a thinner plate with a minimum factor of 2,5 –3. The thinnest plate varies between 0,6 mm and 1,2 mm.
S-type dimple plate
D-type dimple plate
After this spot welding the plates are roller seam welded or TIG welded around the edges.
Under strict quality and safety measurements the welded plates are than inflated using either water or nitrogen at a pressure required to bring the application predetermined pillow height. Than the end connections are welded on and the plates are 100% leak tested in a water bath. A typical inflation pressure is 30 bars. Expansion results then in the typical form of a stitch cushion, the dimples. The mechanical resistance of the Dimple plate by inner or outer pressure depends on the material of construction, the wall thickness and the pattern of the welding points.
To meet various requirements of notified bodies all standard plates (Laser - and or Resistance welded) are designed to with-stand burst pressures at least five times the rated working pressure (example; working pressure of 7 bar, burst pressure >35 bar).
The upper limit currently is approximately 80 bar inner pressure. However, we are developing them further to allow even higher pressure in the future.