Bridge dust-ignition-proof construction cranes of electric type are divided on 5 t, 10 t, 12.5 t, 16 t, 20t and 32t by load-carrying capacity. They are designed for operation in areas of high explosivity B-1, B-Ia, B-Ib, B-Ig, B-II, B -IIa classes that contain gases from groups I, IIA, IIB, IIC having temperature classes T1-T5.
It differs from a traditional crane in its design which is adapted to supply electricity directly from the cable. All surfaces, in the friction of which sparks may appear, are made of a material preventing them from appearing.
The metal structure comes with a factor of safety of 2 against rupture, made of extra high strength steel 09G2S.
All electrical systems of the bridge dust-ignition-proof construction crane (engines, reliefs, limit switches, push-button stations, floodlights, etc.) have an explosion-proof degree, in accordance with the installation zone of the crane and above.
The wheels which move the bucket and crane are made of explosion-proof materials, they have a bronze bandage BRAZH9.
The drives are equipped with explosion-proof electric motors with a short-circuited rotor. There are frequency converters or contractors that are located in the explosion-proof enclosure and play the role of start-up equipment.
Questionnaire on a bridge flameproof cranes