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Electrical equipment with a positive pressure enclosure refers to electrical equipment that has such an enclosure. The explosion protection mark is “p”. A positive-pressure enclosure refers to an enclosure that maintains the pressure of the protective gas inside at a level higher than that of the explosive gas environment surrounding it, thereby preventing external mixtures from entering. Its manufacturing and inspection standards are GB3836.5-2017. Positive pressure explosion protection refers to maintaining the pressure of the protective gas at a level higher than that of the external environment, in order to prevent the formation of an explosive gas atmosphere inside a enclosure that does not contain any sources of flammable gases or vapors ； And when necessary, sufficient amounts of protective gas are introduced into the enclosure to ensure that the concentration of the mixture surrounding the electrical components remains below the explosion limit values corresponding to the specific operating conditions; protective gas is injected into enclosures that contain one or more internal release sources in order to prevent the formation of an explosive gas environment inside the enclosure. Explanation of relevant concepts in positive-pressure explosion protection: Positive-pressure encased electrical equipment comes in three structural types: continuous airflow positive pressure, leakage-compensation positive pressure, and static positive pressure. Continuous gas flow positive pressure refers to a method in which a protective gas continuously flows through a positively pressurized enclosure to keep it at a positive pressure ； Leak compensation positive pressure refers to a method of maintaining a positive pressure inside the enclosure by compensating for the inevitable leaks of the protective gas within the positively pressurized enclosure and pipelines when each exhaust outlet is closed ； Static positive pressure refers to the method of maintaining a positive pressure inside a sealed enclosure in a hazardous area without the use of any protective gas. Positive pressure overpressure: The pressure level within a positively pressurized enclosure that is higher than the external ambient pressure. Pressurization protection: A method that maintains the pressure of the protective gas inside the enclosure at a level higher than the external pressure, in order to prevent explosive gases from entering the enclosure. Pressurization system: A combination of safety devices and other components used for pressurizing and monitoring or controlling a pressurized enclosure. Pressurized enclosure: A enclosure that maintains the pressure of the protective gas inside at a level higher than the external pressure. Protective gas: Air or an inert gas used for ventilation, maintaining positive pressure, and dilution (if required). Note: In this section, inert gases refer to nitrogen, carbon dioxide, argon, or other gases that, when mixed with oxygen in a ratio of 4:1 in air, do not cause ignition, nor do they exhibit flammability characteristics such as an explosion limit. Protective gas supply: The compressor, blower, or compressed gas volume that supplies positive-pressure protective gas. The air supply source includes intake (exhaust) pipes or ducts, pressure regulators, exhaust pipes, ducts, and air supply valves, but does not include components of positive pressure systems. Ventilation/purging: A process in which a large amount of protective gas is passed through the enclosure and pipelines within a positive-pressure enclosure, thereby reducing the concentration of explosive gas mixtures to safe levels. Static pressurization: A protection method that maintains a positive pressure inside the enclosure in hazardous areas without the use of any protective gas. Type px: Reduces the protection level of devices inside the positive-pressure enclosure from Gb or Mb level to a non-hazardous positive-pressure protection. py type: Positive pressure protection that reduces the protection level of devices inside the positive pressure enclosure from Gb level to Gc level. Type PZ: Reduces the protection level of the equipment inside the positive-pressure enclosure from Gc level to a non-hazardous positive-pressure protection. Any platform or individual is prohibited from copying and reproducing it!