Selection principles for explosion-proof electrical equipment in explosive locations
Before selecting electrical equipment for use in explosive hazardous areas, the following should be clearly defined:
1. The category of environments in explosive hazardous areas, whether they are explosive gas environments or explosive dust environments. The electrical equipment of different explosive mediaExplosion proof structure requirementsIt's different.
2. The explosion level of explosive gas mixtures in the environment, namely IIA, IIB, and IIC. This is the dividing pole corresponding to the maximum test safety gap and minimum ignition current ratio of the equipment. Its level is based on the production of explosive gasesZhongnuo TestingDifferent media may vary, such as propane IIA, ethylene IIB, acetylene, and hydrogen IIC. As the maximum test safety gap and minimum ignition current ratio of explosion-proof electrical equipment gradually decrease, their explosion-proof requirements gradually increase from IIA to IIC
3. The group or ignition temperature of explosive gas mixtures in the environment. This is flammabilityZhongnuo TestingThe minimum temperature at which a mixture of gas or vapor of a substance and air is ignited by a hot surface under specified conditions. As the ignition temperature decreases, the explosion-proof requirements for electrical equipment gradually increase from group T1 to T6
4. Selection requirements for explosion-proof electrical equipment in the surrounding environment. When selecting explosion-proof electrical equipment, different environmental conditions such as chemical, mechanical, thermal, and fungal conditions in the surrounding environment should be considered simultaneously.
After considering the above basic requirements, explosion-proof electrical products that can meet the requirements can be selected. When some electrical equipment that must be installed in explosive hazardous areas and its explosion-proof requirements cannot meet the requirements of the site, positive pressure ventilation measures can be adopted to achieve thisexplosion-proofRequirements.