How Does The Supply Air System of A Fume Hood Work?

The main purpose of the supply air system of a fume hood is to discharge harmful gases and dust while maintaining a clean and comfortable indoor environment and preventing the spread of harmful substances to the operator and the outdoor environment. Its working principle and mode can be summarized as follows:

First, working principle

The make-up air system maintains the circulation and balance of indoor air by introducing fresh outdoor air into or in front of the fume hood to replenish the air drawn away by the exhaust system. This helps prevent excessive indoor negative pressure caused by exhaust ventilation, as well as fluctuations in temperature and humidity.

Second, working methods

Make-up air outlet setting:

The make-up air outlets are usually set at the front or side of the fume hood, and some are designed inside the cabinet. These make-up air outlets can ensure that fresh air effectively enters the fume hood, forming an air circulation.

Supplementary air supply power

The make-up air system may rely on natural wind pressure or be powered by dedicated make-up air ducts and make-up fans. For fume hoods that require a large supply air volume, supply fans are usually used to enhance the supply air effect.

Supplementary air filtration

The make-up air entering the fume hood is usually filtered to remove pollutants such as dust and particles, ensuring the quality of the make-up air. This is helpful for maintaining the cleanliness of the laboratory environment.

Air volume control

The make-up air volume needs to be adjusted in real time according to the exhaust air volume to maintain the balance of indoor air. Modern fume hood systems are usually equipped with air volume sensors and controllers, which can automatically monitor and adjust the supply air volume and exhaust air volume.

Third, the type of the air supply system

Natural air supply type:

This type relies on natural wind pressure for air supply and is suitable for situations where the exhaust volume is small and the requirements for air supply are not high. Its advantages are simple structure and low maintenance cost, but the air supply effect may be affected by the external environment.

Powered air supply type

The supplementary air supply powered by the supplementary fan can ensure a stable supplementary air volume and effect. It is suitable for occasions with large exhaust air volume and high requirements for make-up air. However, it increases the equipment cost and the difficulty of maintenance.

Intelligent control type

By integrating intelligent devices such as sensors and controllers, it can automatically adjust the supply air volume and exhaust air volume based on real-time monitoring data, maintaining a stable and comfortable indoor environment. This type has a high level of automation and intelligence, but the cost is also relatively high.

Fourth, maintenance of the make-up air system

To ensure the normal operation and effectiveness of the air supply system, it is necessary to maintain and inspect it regularly. This includes cleaning the air supply outlets, replacing the filters, inspecting the operating conditions of the air supply ducts and air supply fans and other equipment, etc.

In conclusion, the make-up air system of the fume hood replenishes the air drawn away by the exhaust system by introducing fresh outdoor air, thereby maintaining a clean and comfortable indoor environment. Its working principle and mode are diverse, and the appropriate type can be selected for configuration and maintenance according to actual needs.