CT4 and BT4 explosion-proof electric hoist model description and difference
Explosion-proof hoist is two kinds of products widely used in chemical plants and other hazardous areas. General need for explosion-proof scenes such as lifting equipment used in mines is one of the common cases, according to the level can be divided into four categories, from the electric hoist type is divided into CT4 and BT4 two explosion-proof electric hoist. The following two levels of lifting hoist for a detailed introduction, to facilitate our choice according to actual needs.
Model description
CT4 explosion-proof electric hoist explosion-proof grade for ExdIICT4, belongs to the fourth level of explosion-proof. This means that it can be operated safely in environments such as factories, etc. Its surface temperature ratings are, in descending order: T1 (450°C), T2 (300°C), T3 (200°C), T4 (135°C), T5 (100°C), T6 (85°C). Among them, “C” stands for “factory use”, while “T4” indicates the high temperature group that explosion-proof motors can withstand. It is the most extensive level, can be used for explosion-proof level not higher than B or C, ignition temperature group not less than T4 group of flammable gases, vapors and air in the formation of explosive gas environment, the applicable hazardous area for the 1 zone or 2 zone, not applicable to zone 0.
BT4 explosion-proof electric hoist explosion-proof grade for ExdIIBT4, belongs to the third level of explosion-proof, the level of protection is lower than the CT4 explosion-proof motor. Therefore, it is only suitable for ⅡA, ⅡB conditions of use, and ⅡC is not applicable.BT4 electric hoist is slightly narrower than CT4, can not be used for acetylene gas operation place.
In fact, from the meaning of the model, we have been able to see the difference between the use of different gases under the explosion-proof environment, the main difference lies in the explosion-proof grade and scope of application.
Explosion-proof grade and classification
| Type of condition | Gas Classification | Representative Gases | Min Ignition Spark Energy |
|---|---|---|---|
| underground mine | I | methane CH4 | 0.280millijoule (mJ) |
| Factory outside the mine | IIA | methane | 0.180millijoule (mJ) |
| IIB | vinyl | 0.060millijoule (mJ) | |
| IIC | hydrogen | 0.019millijoule (mJ) |
Class I: electrical equipment designated for use in underground coal mines.
Class II : Electrical equipment used in explosive atmospheres, excluding coal mines and underground facilities.
Class II is subdivided into IIA, IIB, and IIC. Equipment labeled IIB is suitable for use in environments where IIA equipment is used; IIC equipment can be used in conditions suitable for IIA and IIB equipment.
Difference between ExdIICT4 and ExdIIBT4
They are suitable for different types of gases.
Ethylene is the typical gas associated with BT4.
Hydrogen and acetylene are typical gases for CT4.
Class CT4 products have a better specification than Class BT4 products because CT4 equipment can be used in environments suitable for BT4, whereas BT4 equipment is not suitable for CT4 environments.
