First, the overall design of explosion-proof electrical products 1, a brief description
90% of non-mine explosion-proof electrical equipment of type II is used in petroleum, offshore oil, petrochemical, chemical industry and pharmaceutical industries (referred to as petrochemical industry for short), and flammable and explosive gases exist in hazardous chemical workplaces in these industries/ There are various types of steam, and the production and storage, transportation, and other processes are complex and changeable, with a wide variety of sources of release. ** Risk factors are difficult to analyze and determine. Therefore, the selection, installation, use and maintenance of explosion-proof electrical equipment are more complicated than mine explosion-proof electrical equipment.
The selection of explosion-proof electrical equipment: First, it is necessary to meet the hazardous areas classified by hazardous areas to select the appropriate type of electrical explosion protection; Second, the level and temperature group of explosion-proof electrical equipment should be selected according to the types of flammable and explosive gases/dusts that may exist in hazardous environments. The third is to consider the impact of other environmental conditions on the explosion-proof performance (such as: chemical corrosion, salt spray, high temperature and humidity, sand and rain, or the impact of vibration); Fourth, to ensure the particularity of installation and maintenance; Fifth, the use of explosion-proof Certificate of conformity and corresponding certified products of the country.
2. Environmental requirements for application of explosion-proof electrical equipment
A.**Hazardous environment/workplace with flammable/explosive gas/vapour.
B. **Hazardous environment/worksite with flammable dust.
C. Environments/workplaces where flammable and explosive gases/vapours and flammable dust are present at the same time, such places are common in solid chemical plants and their transportation, packaging, weighing and coating process equipment. With the development of modern workers, this situation will become more common. Therefore, the selection of explosion-proof electrical equipment in such places has increasingly attracted the attention of design departments and petrochemical companies.
D. At the same time, there are environments or workplaces where corrosive media and other special conditions (high temperature, high humidity, low temperature, sand, rain, and vibration) affect the above three conditions.
3, selection of explosion-proof electrical equipment
According to the level of risk, gas/vapor hazard locations are divided into zones 0, 1 and 2. Their division depends mainly on the degree of release of the release source (**hazardous source), and of course, the buildings in the site. The structure, the capacity of ventilation facilities, and the natural factors in which the place is located will all have an impact on its division, even a great influence.
In the modern petrochemical projects, the area in Area 2 accounts for more than 60%, and the area in Area 1 accounts for about 20-30%; the old chemical companies generally occupy about 50% of the area in Area 1 and Area 2. Zone 0 locations are generally limited to petroleum and chemical installations or smaller discharge areas. For Zone 1 and Zone 2 sites, companies are generally willing to choose the type of explosion-proof electrical equipment used in Zone 1 to improve safety. If the application environment/location is outdoors or there is a slight corrosion, sand storm, the 2 districts are often willing to choose the type of electrical equipment with strong protection, such as: increased safety explosion-proof composite "de", increased safety "e "," "n" type and so on. In addition, in the temperature group, it is willing to choose a group that is higher than the ambient temperature of the ambient gas.
For Zone 0 locations, explosion-proof electrical equipment can only be selected intrinsically safe at the "ia" level. However, the International Electrotechnical Commission IEC60079-26 "Electrical Equipment for Electrical Installations of Particular Types of Gases, Part 26: Structures, Tests, and Signs of Electrical Equipment in Category II, Zone 0" specifically specifies the electrical equipment used in Zone O. Type is more than just ia explosion-proof type.
At present, PCEC has begun to use IEC60079-26 for certification and certification of special electrical equipment used in the Zone 0 environment. Fill the gaps in our standards and meet the needs of the petrochemical industry.
In **hazardous locations, chemical corrosion, salt spray, and other special factors are often at the same time. The influence of these factors will not only damage the electrical and mechanical properties of the equipment, but also seriously destroy the explosion-proof safety performance of the equipment and shorten the equipment's The explosion-proof safety life makes the explosion-proof safety of the equipment uncertain. Therefore, when using explosion-proof electrical equipment in such establishments, it must be confirmed that it has the ability to resist these factors at the same time.
â— Combustible dust refers to both flammable dust and conductive dust.
â— Combustible dust refers to dust that may burn or smolder when mixed with air and form a mixture with air at normal temperature and pressure.
◠Conductive dust refers to dust, fiber, or flying object with a resistivity equal to or less than 1×10 3 Ω·m.
â— Conductive dust is a relatively dangerous dust. If it enters the enclosure of an electrical device, it will adhere to the insulating member of the conductive component, causing a short circuit and failure of the circuit. Therefore, conductive dust can easily cause an ignition source inside the electrical device.
â— The classification of flammable dust hazardous locations is similar to gas hazardous locations and is divided into: Zones 20, 21, and 22.
â— The proportion of pure dust hazardous sites in stone chemical companies is not very large, mainly in the coal chemical industry and granulation process. It is commonplace for gas and dust to coexist.
â— Explosion-proof type of electrical equipment for flammable dust hazardous environment is currently mainly used to protect and limit the surface temperature protection of the structure (GB12476.1-2000), other types of explosion-proof, such as limiting the type of ignition energy, China has no standard regulations, However, the International Electrotechnical Commission has a specific standard (IEC 61241-11:2005) for this type of regulation.
â— For the above-mentioned gas and dust at the same time, the hazardous area equipment selection, must use gas and dust dual explosion-proof explosion-proof electrical equipment, its explosion-proof grade is to meet the characteristics of ** gas, but also to meet the characteristics of flammable dust. This dual-explosion-proof electrical product began mass production in 2005 by some domestic manufacturers. This year will see a large increase in the number of electrical equipment. It is expected that within the next three years, the type of electrical equipment used in such applications will be basically satisfied. demand.
4, the quality of explosion-proof electrical equipment
â— The ** accidents that occur in the production of petroleum and chemical industries mainly include: leakage or reaction of reaction devices caused by high pressure and high temperature; mechanical impact, friction or electrostatic ignition**; electrical spark or high-temperature ignition**. Among them, sparks or high-temperature ignition accidents in electrical equipment occupies a considerable proportion, and are also the first equipment to be controlled and managed in countries all over the world, because the lighting of electrical equipment is not just due to its accident status or misoperation.
â— Because of the determination of petroleum and chemical production processes and facilities and environment, explosion-proof electrical equipment (except power generation, dragging and analysis, and material parameter instruments) is basically an auxiliary production equipment. Therefore, some enterprises lack attention to it and blindly pursue it. The profit index reduces the cost of auxiliary equipment purchases while ignoring the safety of people's lives and property, the poor quality of equipment purchased, the unstable explosion-proof performance, and even poor quality products.
High-quality explosion-proof electrical products are an important guarantee for safety
â— High-quality explosion-proof electrical products are embodied in its reasonable electrical performance and explosion-proof structure design. Explosion-proof parameters and environmental indicators must meet the requirements of the application site. They can still have explosion-proof performance after installation, long-term use, maintenance and overhaul.
â— The manufacture of explosion-proof electrical products must strictly comply with the relevant provisions of the national standards and the special requirements of the application environment.
â— At present, explosion-proof electrical appliances and lighting products used in factories in China are subject to a number of factors such as poor market competition and safety awareness, and there is a general problem of low safety margin.
â— The so-called safety margin is: the product must not only meet the requirements of the corresponding standard, but also ensure that the explosion-proof performance cannot be invalid after installation, use and maintenance.
â— A considerable part of the product is only for the purpose of saving raw materials, reducing costs, meeting the basic requirements for the test sample to meet the standard, and obtaining the explosion-proof certificate, while ignoring the failure of the explosion-proof performance of the user during use.
The correct installation and use of maintenance, to ensure explosion-proof safety performance â— Due to explosion-proof electrical structure, process characteristics, resulting in its explosion-proof quality assurance and other industrial equipment is a great difference.
General industrial equipment as long as the quality of product manufacturing to meet the requirements, the user can basically guarantee the quality after installation and use.
Explosion-proof electrical equipment must not only guarantee explosion-proof safety and quality in the manufacturing process, but also ensure proper installation, use and maintenance, in order to truly achieve the purpose of explosion protection. As such, the quality of the explosion-proof electrical equipment manufacturing and the correct selection, installation and maintenance of the explosion-proof performance in practical applications each occupy 50% of importance. If the explosion-proof electrical equipment is improperly selected, installed, or maintained, the unsafe factors covered by it are more dangerous than those of non-explosive electrical equipment, and this may easily lead to numbness of the user.
Therefore, manufacturing companies must consider the failures that users may cause during the process of design and manufacturing.
Second, explosion-proof electrical appliances and lamps and lanterns should pay attention to the design and manufacture of the correct product design concept
â— National standards are the most basic criteria for development and design.
A product's development and design is not only to meet the requirements of national standards and related standards, but also to consider the user's security interests, as far as possible to take into account the user may be in the installation, use, maintenance, repair process caused by the failure. Improve product safety margins.
â— The vitality and advancement of a product is mainly reflected in its superior performance and reliable work, followed by its practicality and appearance. The guarantee of explosion-proof safety performance is the most basic moral concept for the design and manufacture of an enterprise. The explosion-proof and safe design must be realized around the former.
However, the assurance of explosion-proof performance cannot fully meet the needs of the former. Sometimes, it cannot be achieved, and it is possible to abandon development and design.
â— In the development and design, the cost cannot be used as a basis, and product quality and safety margin should be considered.
Improve explosion-proof electrical technology and correctly understand standards
â— The development of design products should first fully understand the standard, not only the main terms of the standard, but also consider the details and comments in the standard. When examining and testing, the inspection agency strictly enforces the standards and cannot arbitrarily abandon certain clauses and test items in the standard.
90% of non-mine explosion-proof electrical equipment of type II is used in petroleum, offshore oil, petrochemical, chemical industry and pharmaceutical industries (referred to as petrochemical industry for short), and flammable and explosive gases exist in hazardous chemical workplaces in these industries/ There are various types of steam, and the production and storage, transportation, and other processes are complex and changeable, with a wide variety of sources of release. ** Risk factors are difficult to analyze and determine. Therefore, the selection, installation, use and maintenance of explosion-proof electrical equipment are more complicated than mine explosion-proof electrical equipment.
The selection of explosion-proof electrical equipment: First, it is necessary to meet the hazardous areas classified by hazardous areas to select the appropriate type of electrical explosion protection; Second, the level and temperature group of explosion-proof electrical equipment should be selected according to the types of flammable and explosive gases/dusts that may exist in hazardous environments. The third is to consider the impact of other environmental conditions on the explosion-proof performance (such as: chemical corrosion, salt spray, high temperature and humidity, sand and rain, or the impact of vibration); Fourth, to ensure the particularity of installation and maintenance; Fifth, the use of explosion-proof Certificate of conformity and corresponding certified products of the country.
2. Environmental requirements for application of explosion-proof electrical equipment
A.**Hazardous environment/workplace with flammable/explosive gas/vapour.
B. **Hazardous environment/worksite with flammable dust.
C. Environments/workplaces where flammable and explosive gases/vapours and flammable dust are present at the same time, such places are common in solid chemical plants and their transportation, packaging, weighing and coating process equipment. With the development of modern workers, this situation will become more common. Therefore, the selection of explosion-proof electrical equipment in such places has increasingly attracted the attention of design departments and petrochemical companies.
D. At the same time, there are environments or workplaces where corrosive media and other special conditions (high temperature, high humidity, low temperature, sand, rain, and vibration) affect the above three conditions.
3, selection of explosion-proof electrical equipment
According to the level of risk, gas/vapor hazard locations are divided into zones 0, 1 and 2. Their division depends mainly on the degree of release of the release source (**hazardous source), and of course, the buildings in the site. The structure, the capacity of ventilation facilities, and the natural factors in which the place is located will all have an impact on its division, even a great influence.
In the modern petrochemical projects, the area in Area 2 accounts for more than 60%, and the area in Area 1 accounts for about 20-30%; the old chemical companies generally occupy about 50% of the area in Area 1 and Area 2. Zone 0 locations are generally limited to petroleum and chemical installations or smaller discharge areas. For Zone 1 and Zone 2 sites, companies are generally willing to choose the type of explosion-proof electrical equipment used in Zone 1 to improve safety. If the application environment/location is outdoors or there is a slight corrosion, sand storm, the 2 districts are often willing to choose the type of electrical equipment with strong protection, such as: increased safety explosion-proof composite "de", increased safety "e "," "n" type and so on. In addition, in the temperature group, it is willing to choose a group that is higher than the ambient temperature of the ambient gas.
For Zone 0 locations, explosion-proof electrical equipment can only be selected intrinsically safe at the "ia" level. However, the International Electrotechnical Commission IEC60079-26 "Electrical Equipment for Electrical Installations of Particular Types of Gases, Part 26: Structures, Tests, and Signs of Electrical Equipment in Category II, Zone 0" specifically specifies the electrical equipment used in Zone O. Type is more than just ia explosion-proof type.
At present, PCEC has begun to use IEC60079-26 for certification and certification of special electrical equipment used in the Zone 0 environment. Fill the gaps in our standards and meet the needs of the petrochemical industry.
In **hazardous locations, chemical corrosion, salt spray, and other special factors are often at the same time. The influence of these factors will not only damage the electrical and mechanical properties of the equipment, but also seriously destroy the explosion-proof safety performance of the equipment and shorten the equipment's The explosion-proof safety life makes the explosion-proof safety of the equipment uncertain. Therefore, when using explosion-proof electrical equipment in such establishments, it must be confirmed that it has the ability to resist these factors at the same time.
â— Combustible dust refers to both flammable dust and conductive dust.
â— Combustible dust refers to dust that may burn or smolder when mixed with air and form a mixture with air at normal temperature and pressure.
◠Conductive dust refers to dust, fiber, or flying object with a resistivity equal to or less than 1×10 3 Ω·m.
â— Conductive dust is a relatively dangerous dust. If it enters the enclosure of an electrical device, it will adhere to the insulating member of the conductive component, causing a short circuit and failure of the circuit. Therefore, conductive dust can easily cause an ignition source inside the electrical device.
â— The classification of flammable dust hazardous locations is similar to gas hazardous locations and is divided into: Zones 20, 21, and 22.
â— The proportion of pure dust hazardous sites in stone chemical companies is not very large, mainly in the coal chemical industry and granulation process. It is commonplace for gas and dust to coexist.
â— Explosion-proof type of electrical equipment for flammable dust hazardous environment is currently mainly used to protect and limit the surface temperature protection of the structure (GB12476.1-2000), other types of explosion-proof, such as limiting the type of ignition energy, China has no standard regulations, However, the International Electrotechnical Commission has a specific standard (IEC 61241-11:2005) for this type of regulation.
â— For the above-mentioned gas and dust at the same time, the hazardous area equipment selection, must use gas and dust dual explosion-proof explosion-proof electrical equipment, its explosion-proof grade is to meet the characteristics of ** gas, but also to meet the characteristics of flammable dust. This dual-explosion-proof electrical product began mass production in 2005 by some domestic manufacturers. This year will see a large increase in the number of electrical equipment. It is expected that within the next three years, the type of electrical equipment used in such applications will be basically satisfied. demand.
4, the quality of explosion-proof electrical equipment
â— The ** accidents that occur in the production of petroleum and chemical industries mainly include: leakage or reaction of reaction devices caused by high pressure and high temperature; mechanical impact, friction or electrostatic ignition**; electrical spark or high-temperature ignition**. Among them, sparks or high-temperature ignition accidents in electrical equipment occupies a considerable proportion, and are also the first equipment to be controlled and managed in countries all over the world, because the lighting of electrical equipment is not just due to its accident status or misoperation.
â— Because of the determination of petroleum and chemical production processes and facilities and environment, explosion-proof electrical equipment (except power generation, dragging and analysis, and material parameter instruments) is basically an auxiliary production equipment. Therefore, some enterprises lack attention to it and blindly pursue it. The profit index reduces the cost of auxiliary equipment purchases while ignoring the safety of people's lives and property, the poor quality of equipment purchased, the unstable explosion-proof performance, and even poor quality products.
High-quality explosion-proof electrical products are an important guarantee for safety
â— High-quality explosion-proof electrical products are embodied in its reasonable electrical performance and explosion-proof structure design. Explosion-proof parameters and environmental indicators must meet the requirements of the application site. They can still have explosion-proof performance after installation, long-term use, maintenance and overhaul.
â— The manufacture of explosion-proof electrical products must strictly comply with the relevant provisions of the national standards and the special requirements of the application environment.
â— At present, explosion-proof electrical appliances and lighting products used in factories in China are subject to a number of factors such as poor market competition and safety awareness, and there is a general problem of low safety margin.
â— The so-called safety margin is: the product must not only meet the requirements of the corresponding standard, but also ensure that the explosion-proof performance cannot be invalid after installation, use and maintenance.
â— A considerable part of the product is only for the purpose of saving raw materials, reducing costs, meeting the basic requirements for the test sample to meet the standard, and obtaining the explosion-proof certificate, while ignoring the failure of the explosion-proof performance of the user during use.
The correct installation and use of maintenance, to ensure explosion-proof safety performance â— Due to explosion-proof electrical structure, process characteristics, resulting in its explosion-proof quality assurance and other industrial equipment is a great difference.
General industrial equipment as long as the quality of product manufacturing to meet the requirements, the user can basically guarantee the quality after installation and use.
Explosion-proof electrical equipment must not only guarantee explosion-proof safety and quality in the manufacturing process, but also ensure proper installation, use and maintenance, in order to truly achieve the purpose of explosion protection. As such, the quality of the explosion-proof electrical equipment manufacturing and the correct selection, installation and maintenance of the explosion-proof performance in practical applications each occupy 50% of importance. If the explosion-proof electrical equipment is improperly selected, installed, or maintained, the unsafe factors covered by it are more dangerous than those of non-explosive electrical equipment, and this may easily lead to numbness of the user.
Therefore, manufacturing companies must consider the failures that users may cause during the process of design and manufacturing.
Second, explosion-proof electrical appliances and lamps and lanterns should pay attention to the design and manufacture of the correct product design concept
â— National standards are the most basic criteria for development and design.
A product's development and design is not only to meet the requirements of national standards and related standards, but also to consider the user's security interests, as far as possible to take into account the user may be in the installation, use, maintenance, repair process caused by the failure. Improve product safety margins.
â— The vitality and advancement of a product is mainly reflected in its superior performance and reliable work, followed by its practicality and appearance. The guarantee of explosion-proof safety performance is the most basic moral concept for the design and manufacture of an enterprise. The explosion-proof and safe design must be realized around the former.
However, the assurance of explosion-proof performance cannot fully meet the needs of the former. Sometimes, it cannot be achieved, and it is possible to abandon development and design.
â— In the development and design, the cost cannot be used as a basis, and product quality and safety margin should be considered.
Improve explosion-proof electrical technology and correctly understand standards
â— The development of design products should first fully understand the standard, not only the main terms of the standard, but also consider the details and comments in the standard. When examining and testing, the inspection agency strictly enforces the standards and cannot arbitrarily abandon certain clauses and test items in the standard.
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