Classification of explosion-proof measures and corresponding equipment

Classification of explosion-proof measures and corresponding equipment:

1. Flameproof / EEx "d": Separate the circuit from the surrounding environment by means of isolation measures, so that the heat generated by the circuit during normal operation and the spark and high temperature formed in the fault state are limited to the sealed Inside the casing to prevent ignition of the surrounding flammable and explosive gases.

Explosion-proof electrical equipment (d): An electrical device that encloses a component that ignites an explosive mixture in an enclosure that withstands the explosive pressure of the internal explosive mixture and prevents the explosive mixture from escaping with the surrounding.

2. Zengan/EEx “e”: The increased safety type is an additional measure to prevent the arc and sparks under normal operating conditions from taking additional measures to improve the safety and prevent internal and external components. Explosion-proof versions with the possibility of dangerous temperatures, arcs and sparks. It does not include equipment that produces sparks or arcs under normal operating conditions.

Increased safety electrical equipment (e): Under normal operating conditions, there is no spark or dangerous temperature that ignites the explosive mixture, and structural measures are taken to improve its safety to avoid ignition under normal and specified overload conditions. Electrical equipment.

3. Intrinsically safe EEx “i”: By limiting the energy in the electrical circuit and coordinating the structural design of the electrical equipment, it is impossible to generate the point at which the ignition source is required under normal and accidental conditions. The intrinsically safe technology is generally For the complete set, the safety barrier should be set in the safety zone, and the circuit behind the safety barrier is the intrinsically safe equipment. The intrinsically safe circuit card \ terminal \ cable \ plastic Golan should be marked with light blue.

Intrinsically Safe Electrical Equipment (i): Electrical equipment that does not ignite an explosive mixture under normal operating conditions or under standard test conditions.

4, positive pressure / "p": positive pressure shell (ventilated, aerated type) In the outer casing of the equipment, a certain amount of fresh air or inert gas is introduced, so that the surrounding flammable gas can not enter the inside of the casing, thus preventing the ignition source and Contact with explosive gas to prevent explosion.

The key to positive pressure electrical equipment is that the pressure of the protective gas inside the equipment enclosure is at least 50 Pa above the ambient pressure. Therefore, the equipment needs to be equipped with blowers, pipes and wind pressure relays, which are generally used for large motors and control switchgear.

5, oil-filled / "o": the use of oil to live or high-heat parts and flammable environment or isolated from the air to prevent explosion.

6, sand / "q"; and oil-filled principle is similar, but rely on gravel to charge or high-heat parts and flammable environment or isolated from the air to prevent explosion.

7. Non-sparking EEx "n": The equipment does not generate arc or spark under normal operating conditions (refers to the electrical and mechanical requirements of the equipment in accordance with the design specifications and within the specified limits), and does not produce more than the corresponding temperature of the electrical equipment. Groups of high temperature hot surfaces or hot spots do not ignite surrounding explosive mixtures, and generally do not ignite the surrounding explosive mixture. Non-sparking electrical equipment is classified as Class II electrical equipment and is suitable for explosion-proof electrical equipment in factories or open spaces. It is not used in coal mines.

Non-sparking electrical equipment (n): No arcing or sparking under normal operating conditions, nor high temperature surfaces or hot spots capable of igniting the surrounding explosive mixture, and generally no electrical equipment with igniting faults. A common non-sparking electrical device is an electric motor (not including a motor with a sliding contact).

8. Pouring “m”: Poured electrical equipment (m): The electrical equipment or its components are potted in the potting agent so that it cannot ignite the surrounding explosion under normal operation and approved overload or approved failure. Explosion-proof electrical equipment for the mixture.