Theoretical and experimental investigations on flameproof enclosures for hazardous areas

More and more often, electrical equipment, even when they are inside enclosure, need to be often monitored and supervised by operators. This operation can introduce risk especially when they must be opened. Nowadays, most of equipment used in industries, such as Oil & Gas, chemical and pharmaceutics plant, are electrical devices that can be exposed to flammable GAS or DUST. In this kind of ambient, any ignition source like a spark could ignite the substance and leads to a fire or explosion, therefore, the opening of the enclosure is not allowed. Therefore, Flameproof enclosure (Ex d) with large window is becoming very important for hosting electrical devices in Ex area. These new products need to be designed and validate to support a so high mechanical strength (to avoid any possible deformation, failure of enclosure and flame transmission), and normally this validation is obtained only by realizing real enclosure and doing experimental tests. To reduce the number of experimental tests, cost, and time of products design to validate a Flameproof enclosure, in this paper the use of Finite Element Method for stress analysis of an enclosure Electrical Junction Box stainless steel and Aluminum with large window has been described. First, this method has been validated on enclosures realized in stainless steel. Four scenarios have been simulated to improve the yield Safety Factor from the reference model to reach 1 in the final scenario. Finally, the simulation and method have been verified by experimental tests with positive results. Secondly, the validated method has been applied on the enclosure realized in aluminum where a bigger window is installed. The simulation results and the related tests will be shared