Negative pressure fans mainly have the following types:

1. Galvanized sheet negative pressure fan: The shell is made of galvanized sheet material, which has certain anti-rust and corrosion resistance, and the price is relatively economical.

2. Glass fiber reinforced plastic negative pressure fan: The shell is made of glass fiber reinforced plastic (glass fiber reinforced plastic), has good corrosion resistance and strength, suitable for harsh environments.

3. Stainless steel negative pressure fan: The shell is made of stainless steel, with excellent rust and corrosion resistance, which is often used in places with high health requirements or strong corrosion.

4. Square negative pressure fan: The appearance is square, the installation is more convenient, and the air volume is larger.

5. Trumpet negative pressure fan: the shape of the wind blade and the outer frame is similar to the horn, and the air volume is large and the noise is relatively low.

6. Belt type negative pressure fan: the belt drive drives the wind blade to rotate, the operation is relatively stable, and the air volume adjustment range is large.

7. Direct drive negative pressure fan: the motor is directly connected to the wind blade, simple structure and high efficiency.