מחמם אוויר טמפ גבוה
HIGH TEMPERATURE DESIGN CONCEPT
In some cases, the high operating temperature impose a construction which foresees a “distancing” of the electric contact box (“cold head” construction). In these cases each element is fixed both to the plant coupling surface and to the contact box structure using a threaded bushing complete with seal and nut (see Figure 3) If the operating temperature is too high (i.e. > 300 °C) to guarantee tightness by means of seals, the “cold head” construction can be realised introducing distancing tubes, TIG-welded to both surfaces (see Figure 4). This solution is also used when the maximum tightness has to be insured (see, for instance, the case of explosion-proof duct heaters) but does not allow to dismount the heating elements. In all cases the thermal expansion needs of the heating elements are adequately supported.