Analytical instrument explosion-proof three principles
As we all know, the formation of an explosion needs to meet three conditions, namely, oxygen, explosive gas, and detonation source. Because the air is everywhere, we cannot control oxygen. Therefore, controlling explosions can only start from explosive gases and detonation sources. However, there is another principle of explosion protection in the instrumentation industry: control of the explosion range.
Three common explosion-proof principles in instrumentation:
Control of explosive gases
We artificially create a space with no explosive gas in a dangerous place (we call the industrial site with the three conditions required for the explosion at the same time, the dangerous place), and install the instrument in it. A representative example is a positive pressure explosion-proof method. Exp. The working principle is: in a sealed box, it is filled with clean gas or inert gas that does not contain explosive gas, and the pressure inside the box is slightly higher than the pressure outside the box, and the meter is installed in the box. Commonly used in explosion-proof analytical instruments and positive pressure-type instrument cabinets that place computers, PLCs, operation stations or other instruments on site.
Control the scope of the explosion
Artificially limits the explosion to a limited local extent so that explosions in that area do not cause a wider range of explosions. Typical representative is explosion-proof explosion-proof method Exd. The working principle is: Designing a sufficiently rugged housing for the instrument, strictly designing, manufacturing and installing all interfaces in accordance with the standard, so that the explosion occurring in the housing will not cause the explosion of hazardous gas (explosive gas) outside the housing. The design and manufacturing specifications for flameproof explosion protection methods are extremely strict and the operating procedures for installation, wiring and maintenance are also very strict. This method determines that the explosion-proof electrical equipment and instruments are often very heavy and the operation must be powered off, but in many cases it is also the most effective method.
Controlled detonation source
Artificially eliminate the source of ignition, both to eliminate sparks enough to detonate, but also to eliminate the surface temperature rise enough to detonate, the typical representative of the intrinsically safe explosion-proof method. The working principle is: using the safety barrier technology, the electric energy provided to the field instrument is limited to a safety range that can neither generate enough sparks to detonate, nor produce a surface temperature rise enough to detonate the instrument. In accordance with international standards and national standards of China, intrinsically safe explosion-proof methods ensure the explosion-proof safety of hazardous sites when any failure of the equipment connected to the safety zone side of the safety barrier occurs (not exceeding 250V). Exia intrinsically safe equipment does not explode an explosive gas mixture during normal operation, failure, or failure. Therefore, this method is the safest and most reliable explosion protection method.
Three common explosion-proof principles in instrumentation:
Control of explosive gases
We artificially create a space with no explosive gas in a dangerous place (we call the industrial site with the three conditions required for the explosion at the same time, the dangerous place), and install the instrument in it. A representative example is a positive pressure explosion-proof method. Exp. The working principle is: in a sealed box, it is filled with clean gas or inert gas that does not contain explosive gas, and the pressure inside the box is slightly higher than the pressure outside the box, and the meter is installed in the box. Commonly used in explosion-proof analytical instruments and positive pressure-type instrument cabinets that place computers, PLCs, operation stations or other instruments on site.
Control the scope of the explosion
Artificially limits the explosion to a limited local extent so that explosions in that area do not cause a wider range of explosions. Typical representative is explosion-proof explosion-proof method Exd. The working principle is: Designing a sufficiently rugged housing for the instrument, strictly designing, manufacturing and installing all interfaces in accordance with the standard, so that the explosion occurring in the housing will not cause the explosion of hazardous gas (explosive gas) outside the housing. The design and manufacturing specifications for flameproof explosion protection methods are extremely strict and the operating procedures for installation, wiring and maintenance are also very strict. This method determines that the explosion-proof electrical equipment and instruments are often very heavy and the operation must be powered off, but in many cases it is also the most effective method.
Controlled detonation source
Artificially eliminate the source of ignition, both to eliminate sparks enough to detonate, but also to eliminate the surface temperature rise enough to detonate, the typical representative of the intrinsically safe explosion-proof method. The working principle is: using the safety barrier technology, the electric energy provided to the field instrument is limited to a safety range that can neither generate enough sparks to detonate, nor produce a surface temperature rise enough to detonate the instrument. In accordance with international standards and national standards of China, intrinsically safe explosion-proof methods ensure the explosion-proof safety of hazardous sites when any failure of the equipment connected to the safety zone side of the safety barrier occurs (not exceeding 250V). Exia intrinsically safe equipment does not explode an explosive gas mixture during normal operation, failure, or failure. Therefore, this method is the safest and most reliable explosion protection method.
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