Shenhai Ho phatloha-Bopaki
Let’s start by explaining the various explosion-proof ratings, seo ba se bolelang, le mokhoa oa ho li khetha ka ts'ebetso, ho sebelisa mabokose a kabo a thibelang ho phatloha joalo ka mohlala.
| Sehlopha sa khase/sehlopha sa mocheso | T1 | T2 | T3 | T4 | T5 | T6 |
|---|---|---|---|---|---|---|
| IIA | Formaldehyde, toluene, methyl ester, acetylene, propane, acetone, asiti ea acrylic, benzene, styrene, carbon monoxide, ethyl acetate, asiti ea acetic, chlorobenzene, methyl acetate, chlorine | Methanol, ethanol, ethylbenzene, propanol, propylene, butanol, butyl acetate, amyl acetate, cyclopentane | Pentane, pentanol, hexane, ethanol, heptane, octane, cyclohexanol, turpentine, naphtha, petroleum (ho akarelletsa le peterole), oli ea mafura, pentanol tetrachloride | Acetaldehyde, trimethylamine | Ethyl nitrite | |
| IIB | Ester ea propylene, dimethyl ether | Butadiene, epoxy propane, ethylene | Dimethyl ether, acrolein, hydrogen carbide | |||
| IIC | Haedrojene, khase ea metsi | Acetylene | Carbon disulfide | Ethyl nitrate |
Letšoao la setifikeiti:
Ex d IIB T4 Gb/Ex tD A21 IP65 T130°C ke setifikeiti sa bokahohle sa tšireletso ea khase le lerōle., where the part before the slash (/) indicates the gas explosion-proof level, and the part after the slash indicates dust explosion-proof.
Ex: Explosion-proof marking, the standard format of IEC (International Electrotechnical Commission) litekanyetso tsa bopaki ba ho phatloha.
d: E thibelang mollo mofuta, indicating the primary form of explosion protection is flameproof.
IIB: Represents Class B gas explosion protection.
T4: Indicates the mocheso class.
Gb: Indicates this product is suitable for Zone 1 tshireletso ya ho phatloha.
For the ho phatloha ha lerole part in the latter half, it’s sufficient to achieve the highest dust protection grade 6 based on the gas explosion-proof standards.
tD: Represents the type of enclosure protection (preventing dust ignition with enclosure).
A21: Indicates the applicable area, suitable for Zone 21, Sebaka 22.
IP65: Represents the protection grade.
It’s crucial to choose the correct explosion-proof rating in actual environments.
Ea pele, it’s important to understand two main categories, as described below:
Explosion-proof types:
Sehlopha sa I: Electrical equipment for underground coal mines;
Sehlopha sa II: Electrical equipment for all other qhoma gas environments except coal mines and underground.
Class II can be divided into IIA, IIB, le IIC, where equipment marked IIB can be used under conditions suitable for IIA devices; IIC can be used under conditions suitable for both IIA and IIB.
Sehlopha sa III: Electrical equipment for explosive dust environments other than coal mines.
IIIA: Combustible flyings; IIIB: Lerōle le se nang conductive; IIIC: Lerōle le tsamaisang.
Explosion-proof areas:
Sebaka 0: Where explosive gases are always or frequently present; continuously hazardous for more than 1000 hours/year;
Sebaka 1: Where e ka chang gases might occur during normal operation; intermittently hazardous for 10 ho 1000 hours/year;
Sebaka 2: Where flammable gases are not normally present and, if they occur, are likely to be infrequent and short-lived; hazardously present for 0.1 ho 10 hours/year.
It is important to note that we deal with Class II and III, Sebaka 1, Sebaka 2; Sebaka 21, Sebaka 22.
Ka tloaelo, reaching IIB is sufficient for gases, but for haedrojene, acetylene, le carbon disulfide, a higher level of IIC is required. For dust explosion protection, just achieve the corresponding gas boemo ba bopaki ba ho phatloha and the highest dust grade.
There’s also a combined type of lebokose la kabo la bopaki ba ho phatloha rating: ExdeIIBT4Gb.