Components of a ventilation system: bathroom extractors

What is a fan?

A fan is a rotating machine that sets the air in motion. It can thus be defined as a turbomachine that transmits energy to generate the necessary pressure to maintain a continuous airflow.

Types of fans

Depending on the function the fan performs, these can be:

1. Impeller Fans: they have a free entry for air and a ducted exit.
2. Extractor Fans: both the entry and the exit of the fan are ducted.
3. Wall Fans: also known as extractors, and they function to transfer air between two spaces separated by a wall.
4. Jet Fans: are fans used to project a stream of air impacting on people or things.

According to the air path, the fans can be:

1. Centrifugal Fans: in these fans, the air path follows an axial direction at the entry and parallel to a radial plane at the exit. Therefore, entry and exit are at right angles.
2. Axial Fans: the air enters the device and exits following a trajectory along coaxial cylindrical surfaces.
3. Transverse Fans: the air path in the impeller of these fans is normal to the axis at both entry and exit.

Depending on the pressure, fans can be:

1. Low Pressure Fans: those that do not exceed 70 Pascals. They are usually centrifugal fans.
2. Medium Pressure Fans: are fans in which the pressure is between 70 and 3,000 Pascals. They can be centrifugal or axial.
3. High Pressure Fans: in these, the pressure is above 3,000 Pascals. They are usually centrifugal with narrow internal impellers and large diameter.

Types of bathroom extractors

A specific type of fan is the bathroom extractors, which are electrical devices designed to air and ventilate the room, as well as to reduce bad odors and mold that appears due to humidity. By preventing condensation, they also help to keep the walls, ceilings, and joints in bathrooms in good condition. There are three types of extractors:

1. Axial Extractors: are extractors that are placed on the ceiling, walls or windows. They are indicated for installations with reduced ducts.
2. Helicoidal Extractors: are installed in windows or exterior walls, without any evacuation duct.
3. Centrifugal Extractors: are more powerful than the previous ones and are indicated for those installations where the evacuation ducts cover large distances to the exit, of up to 50 meters.

Also, according to their operation, the following types of extractors can be distinguished:

1. Manual: need to be activated by a switch.
2. With presence detector: are activated when they detect presence via infrared in the space they cover.
3. Hygrostats: include sensors (humidistats) that activate the extractor based on the humidity in the environment.
4. With timer: remain active for the necessary time to renew the contaminated air, and turn off once that time has elapsed.