Negative pressure fan is a strong exhaust equipment, can exhaust indoor gas, so that the indoor pressure becomes low, so called negative pressure fan. And positive pressure fan is forced air supply equipment, with negative pressure fan just the opposite.

First, exhaust principle is different:

1. The negative pressure fan exhautes the air to make the indoor pressure drop, the indoor air becomes thinner, forming a negative pressure area, and the air flows into the room due to the pressure difference compensation.

2. The principle of positive pressure fan is opposite to negative pressure fan.

Two, different functions:

1. The main function of negative pressure fan is ventilation, smoke exhaust and peculiar smell exhaust. 2. Positive pressure fan is the fan that points to the air supply in the escape corridor. It sends outdoor wind pressure into the room. When the building fire, will produce a lot of smoke, carbon monoxide and other toxic gases and block the sight, through the positive pressure fan to escape the fire stairs, so that the indoor smoke can not reach the stairs, to create conditions for people to escape.

Three, installation is different:

1. The positive pressure blower is generally installed on the top of the building and linked with the positive pressure air valve of each layer.

2. The negative pressure blower is installed outside the window of the workshop. Generally, the outlet is selected to pump out the air and extract the peculiar smell gas. The positive pressure blower is directed to the air blower in the escape corridor. It sends outdoor wind pressure into the room. When the building fire, will produce a lot of smoke, carbon monoxide and other toxic gases and block the sight, through the positive pressure fan to escape the fire stairs, so that the indoor smoke can not reach the stairs, to create conditions for people to escape.