In a potentially explosive storage area, 3 doors (4000 x 4000 mm, weight approx. 1100 kg) have been equipped with the DICTATOR DICTAMAT 700 EX door operator. The door operators, however, not only have to meet the ATEX demands but also those of the fire protection agency.
The doors are opened by motor. For the mechanic closing are used the counterweights mounted by the customer. This assures that in case of a power cut and simultaneous fire alarm the doors always reliably close. But this also means that the explosion proof gearbox has to run smoothly as otherwise it would not be possible to close the doors by counterweight. This required an especially ambitious solution as explosion proof gearboxes usually are rough-running.
Special features of the sliding doors:
- They are equipped with a liquid barrier which ensures that dangerous liquids cannot spread.
- In the closed position the doors are lowered to make sure that the opening is tightly closed. For a reliable opening despite the lowered position, an additional small counterweight assists the door operator on the first 400 mm.
- The control systems for the door operators had to be mounted in the hazardous area as well. Therefore, they were mounted in an ex-proof casing.
In this building antistatic toothed belts are used for power transmission.