Difference between negative pressure fan and positive pressure fan

A negative pressure fan is a machine that naturally draws in fresh air from a door or window opposite the installation site and quickly forces the indoor heat out of the room. Any problems with poor ventilation can be improved and the cooling and ventilation is very effective. A positive pressure fan is a fan that sends air into an escape building. It sends outdoor air pressure into the room. When a fire occurs in a building, it will produce large star smoke dew, carbon monoxide and other toxic gases and speed blocking the line of sight, through the positive pressure fan to escape the fire stairs to send air, so that the indoor 6 fog can not arrive at the building whisk, to the people to choose the life to create conditions. So, what is the difference between negative pressure fan and positive pressure fan?
1, different installation
Positive pressure fan is usually installed in the building windows, and negative pressure fan is usually installed in the workshop outside the window and lower outlet, easy to suck the air to the outside and introduce fresh outdoor air, in order to achieve the effect of air convection. 2, different exhaust principle
Negative pressure fan to the outside exhaust, so that the indoor air thin, thus forming a negative pressure zone, outdoor air inflow, to achieve the effect of ventilation. On the contrary, positive pressure fan, is indoor air extraction. 3, different functions
Negative pressure fan is mainly ventilation and cooling, eliminate odor and dust.
Positive pressure fan is usually used in the escape corridor. When a fire accident occurs, its internal motor will open the air outlet, smoke dew or manual fire alarm will be opened. The positive pressure air livery at the top of the tower will automatically open to supply compressed air to the supply shaft. The front room of the staircase will be continuously supplied with air to the front room through the positive pressure air supply outlet to maintain positive pressure in the front child to ensure that smoke will not spread in this area, thus giving space for people to escape. When the temperature is higher than 280C, there is no possibility for people to escape, its internal fuse will blow and the air outlet will close automatically to prevent the fire from spreading.
A major cause of indoor air is stagnant indoor air that flows at a certain speed, which naturally lowers the temperature. It is well known that electric fans do not change the temperature, but they can be utilized to cool a person with a weak agitating airflow. If there is a draft in the passage between two buildings, it will be colder than a shop space where sealed air is not flowing. In fact, negative pressure fans utilize the physical principles of negative pressure ventilation, air convection, and the creation of “through-flow” to achieve indoor cooling.
These are the differences between the two. Negative pressure fan has the advantages of low investment cost, large wind star, low noise, low energy consumption, stable operation, long service life and high efficiency. Shutters can be automatically opened and closed to realize dustproof, waterproof, beauty now generous. It can blow and exhaust, which is a good choice for modern workshop cooling and ventilation.