- All
- Product Name
- Product Keyword
- Product Model
- Product Summary
- Product Description
- Multi Field Search
Views: 0 Author: Site Editor Publish Time: 2024-06-28 Origin: Site
Why choose explosion-proof?
Many production sites produce flammable substances, with about two-thirds of underground coal mines containing explosive substances. In the chemical industry, more than 80% of production workshop areas contain explosive substances. The oxygen required for an explosion is ubiquitous.
The electrical instruments widely used in the production process, various frictional sparks, mechanical wear sparks, electrostatic sparks, high temperatures, etc. are inevitable and act as ignition sources.
Therefore, in many industrial sites, when the concentration of explosive substances mixed with oxygen reaches the explosive limit, if there is an ignition source, an explosion will occur. Therefore, it is necessary to adopt explosion-proof measures.
Interpretation of explosion-proof level
Explosion proof sign format
Explosion proof sign format | ||||
Explosion proof marking | Explosion proof structural form | Explosion proof equipment category | Gas group | Temperature group |
EX | D/p/i, etc | Ⅰ/Ⅱ | A/B/C | T1~T6 |
For example
Ex d Ⅱ C T4
① ② ③ ④ ⑤
01 EX represents China and the International Electrotechnical Commission's explosion-proof marking
02 It indicates that different explosion-proof types are applicable to different hazardous locations. d represents explosion-proof type.
No | Explosion proof form | Code | National standard | Explosion proof measures | Applicable area |
Explosion proof type | d | GB3836.2 | Isolate the existing ignition source | Zone1,Zone2 | |
2 | Increased safety type | e | GB3836.3 | Try to prevent the generation of ignition sources | Zone1,Zone2 |
3 | Intrinsically safe type | ia | GB3836.4 | Limiting the energy of ignition sources | Zone0-2 |
Intrinsically safe type | ib | GB3836.4 | Limiting the energy of ignition sources | Zone1,Zone2 | |
4 | Pressurized type | p | GB3836.5 | Isolate hazardous substances from ignition sources | Zone1,Zone2 |
5 | Oil filled type | o | GB3836.6 | Isolate hazardous substances from ignition sources | Zone1,Zone2 |
6 | Sand filled type | q | GB3836.7 | Isolate hazardous substances from ignition sources | Zone1,Zone2 |
7 | non-sparking type | n | GB3836.8 | Try to prevent the generation of ignition sources | Zone2 |
8 | encapsulated type | m | GB3836.9 | Try to prevent the generation of ignition sources | Zone1,Zone2 |
9 | hermetically sealed | h | GB3836.10 | Try to prevent the generation of ignition sources | Zone1,Zone2 |
03 Ⅰ——Coal mine and underground electrical equipment
Ⅱ——Electrical equipment other than coal mines and underground use
04 Classification of explosive hazardous gases
According to the minimum possible spark energy, explosive gases are classified into four hazard levels in China, Europe, and most countries and regions around the world, as shown in the table below:
Working condition category | Gas classification | Representative gases | Minimum ignition spark energy |
Under the mine | Ⅰ | Methane | 0.280mJ |
Factory outside the mine | ⅡA | Ethane | 0.180mJ |
ⅡB | Ethylene | 0.060mJ | |
ⅡC | H2 | 0.019mJ |
05 Classification of gas temperature groups
According to the highest surface temperature of the equipment, it is divided into six groups: T1 to T6, as shown in the following figure:
Temperature group | Safe surface temperature of objects | Common explosive gases |
T1 | ≤450℃ | hydrogen, acrylonitrile, etc，46types |
T2 | ≤300℃ | Acetylene ethylene,etc，47types |
T3 | ≤200℃ | Gasoline, butyraldehyde,etc，36types |
T4 | ≤135℃ | Acetaldehyde, tetrafluoroethylene ,etc，6types |
T5 | ≤100℃ | CS2 |
T6 | ≤85℃ | Ethyl nitrate, ethyl nitrite |
The explosion-proof mark of the instrument: Ex (ia) ⅡC T6 means:
Content | Symbol | Meaning |
Explosion proof declaration | Ex | Meets certain explosion-proof standards, such as China's national standards |
Explosion proof type | ia | Adopting ia level intrinsic safety explosion-proof method,it can be installed in Zone 0 |
Gas category | ⅡC | Admitted to involve Class IIC explosive gases |
Temperature group | T6 | The surface temperature of the instrument shall not exceed 85 ℃ |
The meaning of Ex (ia) ⅡC:
Content | Symbol | Meaning |
Explosion proof declaration | Complies with European explosion-proof standards | |
Explosion proof type | Adopting ia level intrinsic safety explosion-proof method,it can be installed in Zone 0 | |
Gas category | Admitted to involve Class IIC explosive gases |
Note: There is no temperature category item in this symbol, indicating that the instrument does not come into direct contact with explosive gases
The composition and meaning of protective signs
IP protection grade
The IP (Ingress Protection) protection level system was drafted by the IEC (International Electrotechnical Commission). Classify electrical appliances according to their dust and moisture resistance characteristics.
01 Composition of identification
The IP protection level is composed of two numbers. The first number represents the level of dust separation and prevention of foreign object intrusion in electrical appliances, while the second number represents the degree of sealing of electrical appliances against moisture and water intrusion. The larger the number, the higher the protection level.
02 The IP protection category is marked with two numbers:
For example, an protection category: IP XX
Marking letters
The first marked number
The second marked number
The first marking number of contact protection and foreign object protection levels | ||
The first marking number | Protection range | |
Name | Note | |
0 | Non-protection | -- |
1 | Protect against foreign objects with a diameter of 50mm and larger | Detector, with a sphere diameter of 50mm, should not enter completely |
2 | Protect against foreign objects with a diameter of 12.5mm and larger | Detector, with a sphere diameter of 12.5mm, should not enter completely |
3 | Protect against foreign objects with a diameter of 2.5mm and larger | Detector, with a sphere diameter of 2.5mm, should not enter completely |
4 | Protect against foreign objects with a diameter of 1.0mm and larger | Detector, with a sphere diameter of 1.0mm, should not enter completely |
5 | Dust protection | It is impossible to completely prevent dust from entering, but the amount of dust entering should not exceed such a quantity as to cause damage to the device or safety |
6 | Dust sealing | Dust should not enter the box at a low pressure of 20 millibars |
The second marking number of protection level | ||
The second marking number | Protection range | |
Name | Note | |
0 | Unprotected | -- |
1 | Water droplet protection | Vertically falling water droplets should not cause damage. |
2 | When the box is tilted at 15 °, protect against water droplets | When the box is tilted to any side at a 15 ° angle, vertically falling water droplets should not cause damage |
3 | When the box is tilted at 15 °, protect against water droplets | Water splashed from both sides of the vertical line at a 60 ° angle should not cause damage. |
4 | Protective water spray | The water spray aimed at the box from each direction should not cause damage |
5 | Protective water jet | The water jet aimed at the box from each direction should not cause damage. |
6 | Protection against strong water jet | The strong water jet aimed at the box from each direction should not cause damage. |
7 | Protection against short-term immersion in water | When the box is immersed in water for a short period of time under standard pressure, there should be no water that can cause harmful effects |
8 | Protection against long-term immersion in water | The box must be immersed in water for a long time under the conditions agreed upon by the manufacturer and the user, and there should be no water that can cause harmful effects. But these conditions must be more complex than those specified by the number 7 marker |
The highest test level for IP protection is IP68, but common claimed levels are still IP54, IP55, IP65, IP66, IP67, IP68, etc.
