1. Explosion-proof level
Explosion-proof grade is a key indicator used to measure the explosion-proof performance of explosion-proof electrical equipment. It comprehensively reflects the ability of the equipment to prevent explosions in different hazardous environments. There are many common international standards for classifying explosion-proof levels. Taking gas explosion-proof as an example, IEC standards are often referred to.
1. Explosion-proof type "d": Its explosion-proof principle is to make the equipment shell have high strength and be able to withstand the huge pressure generated by the internal explosion, and can effectively prevent the flames generated by the explosion from spreading to the surrounding environment through the gaps between the various components of the shell, preventing Ignite external explosive gas mixtures and are often used in large motors, control cabinets and other equipment in areas with high explosion risks such as refineries and natural gas processing stations.
2. Increased safety "e": The focus is to improve the safety of the electrical equipment itself, such as strictly limiting the operating temperature of the equipment to prevent overheating from being high enough to ignite explosive mixtures; at the same time, by optimizing electrical connections and increasing Insulation protection and other measures should be taken to avoid sparks. For example, some small fans and lighting fixtures in petrochemical enterprises often adopt the increased safety type, which not only meets the basic explosion-proof requirements, but also takes into account cost and practicality.
3. Intrinsically safe "i": This type of equipment is extremely special. Whether in normal working condition or in the event of a malfunction, the energy it generates is always maintained at a very low level, which is not enough to ignite the surrounding explosive materials. Gas or dust mixtures are often used in environments with extremely high safety requirements and trace amounts of explosive substances, such as gas monitoring sensors in coal mines and certain precision instruments in chemical production.
In China, the explosion-proof level is also based on the GB 3836 standard and combined with the division of hazardous areas (Zone 0, Zone 1, and Zone 2) to determine the applicable level of the equipment. Generally speaking, Zone 0 has the highest requirements and requires the use of equipment with excellent explosion-proof performance, such as specially designed intrinsically safe or explosion-proof composite equipment; Zone 1 is second, and explosion-proof, increased safety, etc. can be used; 2 The area is relatively loose, and some ordinary equipment with increased safety or explosion-proof modifications can also meet the requirements.
2. Protection level
The protection level mainly measures the device's ability to protect against physical factors such as external foreign matter intrusion, moisture infiltration, and mechanical impact, and is usually represented by an IP code. IP is followed by two numbers, the first number indicates the dustproof level, and the second number indicates the waterproof level.
4. Dust-proof level: increasing step by step from 0 to 6. Level 0 means no protection, the equipment is completely open, and dust can enter at will; Level 6 means the equipment has super dust-proof capabilities. Even if it is operated for a long time in a dusty environment, dust is almost impossible to invade, such as communications in desert areas. Base station equipment requires a high dust-proof level to prevent sand and dust from damaging internal electronic components.
5. Waterproof level: gradually increasing from 0 to 8. Level 0 is also unprotected and will be affected by water; Level 8 means that the equipment can still work normally after being soaked under a certain water pressure for a long time, such as underwater robots and swimming pool lighting equipment, etc., must reach a high waterproof level to ensure Reliable operation in water environments.
In practical applications, explosion-proof equipment often needs to take into account both the explosion-proof level and the protection level. For example, on an offshore oil drilling platform, there is not only a flammable and explosive oil and gas environment, but also facing harsh conditions such as seawater erosion and sea breeze dust. Therefore, electrical equipment must be selected that can meet the corresponding explosion-proof level and have a higher protection level. products to ensure the safe production and continued operation of the platform.
In short, understanding the explosion-proof level and protection level will help to correctly select and use appropriate equipment under different dangerous and complex working conditions to ensure the safety of personnel, equipment and production processes to the greatest extent.
3. Explosion-proof signs
Explosion-proof signs are signs used to indicate key information such as equipment’s explosion-proof type and applicable area. It usually consists of explosion-proof symbols, explosion-proof levels and applicable hazardous areas.
Taking common explosion-proof electrical equipment as an example, its explosion-proof mark may be "Ex d Ⅱ B T4", where "Ex" is the internationally accepted explosion-proof mark; "d" represents explosion-proof type; "II" means that the equipment is suitable for factories Electrical equipment is classified according to different gases and vapors, including Class I (electrical equipment under coal mines), etc.; "B" It is a classification of gases and vapors. Different levels correspond to different maximum test safety gaps and minimum ignition current ratios, which are used to distinguish explosive media with different levels of danger. For example, Class A is more likely to be ignited than Class B; "T4" Refers to the maximum surface temperature group of the equipment, which stipulates the upper limit of the surface temperature of the shell during normal operation of the equipment to prevent the explosion of surrounding explosive mixtures due to high temperature, T4 Indicates that the surface temperature of the equipment does not exceed 135°C, similar to T1 (450°C), T2 (300°C), T3 (200°C), etc.
Different explosion-proof types of equipment have their own corresponding explosion-proof signs. Intrinsically safe equipment may be marked as "Ex i IIC T6", which means that it is suitable for factory use, targeting IIC explosive media that is more likely to ignite, and the surface temperature does not exceed 85°C. , fully reflecting its high security. The explosion-proof markings of increased safety equipment generally include “Ex e” and other relevant information, highlighting its explosion-proof characteristics through enhanced safety.
In practical applications, people can quickly understand the explosion-proof performance and applicable scope of equipment through the explosion-proof signs, so that they can accurately select models in different hazardous environments and ensure safe production.
In practical applications, explosion-proof equipment often needs to take into account both the explosion-proof level and the protection level. For example, on an offshore oil drilling platform, there is not only a flammable and explosive oil and gas environment, but also facing harsh conditions such as seawater erosion and sea breeze dust. Therefore, electrical equipment must be selected that can meet the corresponding explosion-proof level and have a higher protection level. products to ensure the safe production and continued operation of the platform.
In short, understanding the explosion-proof level, protection level and explosion-proof signs will help to correctly select and use appropriate equipment under different dangerous and complex working conditions to ensure the safety of personnel, equipment and production processes to the greatest extent.