1、The outer frame material of the fan is optional: galvanized sheet, 201 stainless steel, 304 stainless steel. 2、Explosion-proof negative pressure fan is mainly suitable for flammable and explosive gas environment, humid and harsh environment. Reliable explosion-proof performance, large air volume and low noise. 3、Fan size can be customized 4、The fan blade is made by one-time stamping of the mold, which is beautiful and durable. The special blade shape design ensures large air volume and no deformation. 5、Explosion-proof grade Exd II BT4 Explosion-proof motor, durable and powerful, motor protection grade IP 55, insulation grade: F grade. 6、The aluminum wheel and blade angle are made of aluminum magnesium alloy,with light weight, good toughness, and are not easy to damage.Definition of explosion-proof equipment: electrical equipment that will not cause ignition in the surrounding explosive environment under specified conditions. Explosion-proof products have an explosion-proof grade, and the explosion-proof form and applicable occasions of the product can be seen from the explosion-proof grade. For example, the explosion-proof level of Exd II BT4 is described below. Ex: Explosion-proof mark d: The explosion-proof form is flameproof type. There are intrinsically safe type IA and IB; Increased safety type E; Oil filled o; Sand filling mold Q; Pouring and sealing type m; Composite type (for example, de combination is often used for explosion-proof distribution box). II: Refers to Class II explosion-proof electrical equipment. This type of explosion-proof electrical appliances is suitable for other explosive gas environments except coal mines. (Coal mines are Class I). There are also class III: electrical equipment for explosive dust atmospheres except coal mines. Class IIIA: flammable flying flocs; Class IIIB: non-conductive dust; Class IIIC: conductive dust. B: Class IIB gas. There are also IIC and IIA grades. Class IIC is the highest level and can be applied to both IIA and IIB. Level IIB can be applied to Level IIA. But the low-level can't apply to the high-level. T4: The temperature group is T4, and the maximum surface temperature of the equipment is less than 135°C.