1. Categories, levels and temperature groups of explosion-proof solenoid valves
1.1. Division of hazardous areas for explosive gas environments
Zone 0: Continuous or long-term explosion Gas mixture environment.
Zone 1: An environment where explosive gas mixtures may occur during normal operation.
Zone 2: An environment in which explosive gas mixtures are unlikely to occur during normal operation or where explosive gas mixtures will only exist for a short period of time even if they occur.
Zone 0: Generally only exists in internal gas spaces such as sealed containers and storage tanks. In the actual design process, Zone 1 rarely exists, and most cases belong to Zone 2.
1.2. Explosion-proof electrical equipment is divided into two categories:
Class I electrical equipment for underground coal mines
Class II electrical equipment for use in places other than mines
1.3. Class II electrical equipment, according to its application The maximum test safety gap or minimum ignition current ratio for explosive gas mixtures is divided into three categories: IIA, IIB, and IIC;according to its maximum surface temperature, it is divided into six groups: T1-T6. (IIC is the highest level of explosion-proof type and can cover the application range of IIA and IIB.
1.4. Explosive gas mixtures are grouped according to ignition temperature, see Table 1.
1.5. Explosive gas mixtures are classified according to their maximum test Safety gap (MESG) or minimum ignition current ratio (MICR) classification, see Table 2
Table 1
1.1. Division of hazardous areas for explosive gas environments
Zone 0: Continuous or long-term explosion Gas mixture environment.
Zone 1: An environment where explosive gas mixtures may occur during normal operation.
Zone 2: An environment in which explosive gas mixtures are unlikely to occur during normal operation or where explosive gas mixtures will only exist for a short period of time even if they occur.
Zone 0: Generally only exists in internal gas spaces such as sealed containers and storage tanks. In the actual design process, Zone 1 rarely exists, and most cases belong to Zone 2.
1.2. Explosion-proof electrical equipment is divided into two categories:
Class I electrical equipment for underground coal mines
Class II electrical equipment for use in places other than mines
1.3. Class II electrical equipment, according to its application The maximum test safety gap or minimum ignition current ratio for explosive gas mixtures is divided into three categories: IIA, IIB, and IIC;according to its maximum surface temperature, it is divided into six groups: T1-T6. (IIC is the highest level of explosion-proof type and can cover the application range of IIA and IIB.
1.4. Explosive gas mixtures are grouped according to ignition temperature, see Table 1.
1.5. Explosive gas mixtures are classified according to their maximum test Safety gap (MESG) or minimum ignition current ratio (MICR) classification, see Table 2
Table 1
| Group | Ignition temperature T (℃) | ||
| T1 | <450 | ||
| T2 | <300 | ||
| T3 | <200 | ||
| T4 | <135 | ||
| T5 | <100 | ||
| T6 | <85 |
Table 2
| Category | Maximum test safety gap (MESG) (mm) | Minimum Ignition Current Ratio (MICR) | |
| II A | ≥0.9 | 0.8 | |
| II B | 0.5| 0.45≤MICR≤0.8 | | |
| II C | ≤0.5 | <0.45 | |
2. Noun predicate
2.1. Flameproof electrical equipment can withstand the explosion pressure of the internal explosive gas mixture and prevent the internal explosion from propagating to the explosive mixture around the shell. The electrical equipment enclosure is marked "d".
2.2. Increased safety electrical equipment will not produce arcs, sparks or high temperatures that may ignite explosive mixtures under normal operating conditions. Structural measures should be taken to improve the safety margin to avoid arcs under normal and approved overload conditions. , sparks or high-temperature electrical equipment, the mark is "e"
2.1. Flameproof electrical equipment can withstand the explosion pressure of the internal explosive gas mixture and prevent the internal explosion from propagating to the explosive mixture around the shell. The electrical equipment enclosure is marked "d".
2.2. Increased safety electrical equipment will not produce arcs, sparks or high temperatures that may ignite explosive mixtures under normal operating conditions. Structural measures should be taken to improve the safety margin to avoid arcs under normal and approved overload conditions. , sparks or high-temperature electrical equipment, the mark is "e"
| Explosion-proof type | logo | Principles of explosion prevention |
| Explosionproof type | d | Place the components that can generate sparks and arcs in the explosion-proof enclosure when the equipment is in normal operation. The explosion-proof enclosure can withstand the internal explosion pressure without being damaged, and can ensure the internal flame gas When propagating through the gap, the energy is reduced and is not enough to detonate the gas outside the shell. |
| Increased safety type | e | During normal operation, arcs, sparks and dangerous high temperatures will not be generated. In terms of structure, we will further take protective measures to improve the safety and reliability of the equipment. |
| Positive pressure type | p | Keep the pressure of the internal protective gas higher than the surrounding pressure to prevent the explosive mixture from entering the shell or pass a sufficient amount of protective gas through the shell to reduce the concentration of the explosive mixture inside to below the lower explosion limit. |
| Intrinsically safe type | i | Under specified conditions, the electrical sparks and thermal effects generated by the circuit inside the equipment during normal operation or specified fault conditions cannot ignite explosive mixtures. |
| Pouring type | m | It encapsulates parts that may produce arcs, sparks or high temperatures that may ignite explosive mixtures, so that they cannot ignite surrounding explosive mixtures. |
WhatsApp: +8615857777578