Classification of exhaust hoods

At work, in the face of dust and poison, the most commonly used occupational disease hazard protection facility is the exhaust hood. It can effectively absorb and treat the dust poison on the job site, so as to achieve the purpose of reducing the concentration of pollutants in the air. 

How are exhaust hoods classified?

In "GB/T 16758-2008 Classification and Technical Conditions of Exhaust Hoods", the exhaust hoods are divided into 6 categories:

1. Airtight hood: an exhaust hood that seals harmful substances in the hood. According to their different designs and usage scenarios, they are divided into the following four categories:

(1) Partial airtight hood: an exhaust hood that only seals the part of the process equipment that releases harmful substances.

(2) Overall airtight hood: an exhaust hood that seals most or all of the equipment that releases harmful substances.

(3) Large-volume airtight hood: an exhaust hood that completely seals the equipment or related technological processes that release harmful substances in a large range.

(4) Exhaust hood: a cabinet-type exhaust hood with three sides enclosed on one side open or equipped with a working hole for operating a sliding door.

2. External hood: set near the source of harmful substances, and rely on the suction effect of the hood to form an exhaust hood at the control point to remove harmful substances with a certain wind speed. According to their different settings, they are divided into upper suction hood, lower suction hood and side suction hood.

(1) The upper suction hood, also known as the top suction hood, is an outer cover set on the upper part of the source of harmful substances.

(2) Lower suction hood: Also called bottom suction hood, it is an outer cover set at the lower part of the source of harmful substances.

(3) Side suction hood: the external cover set on the side of the harmful substance source, such as the external hood set on the side of the industrial tank (electroplating tank, pickling tank, etc.) of the three-way harmful substance, also called the tank side cover.

3. Receiving hood: an exhaust hood that passively receives the harmful airflow generated or induced by the production process (such as thermal process and mechanical movement process), such as the dust hood of the grinding machine, the umbrella-shaped hood on the upper part of the high temperature heat source, etc.

4. Blowing and suction hood: an exhaust hood that captures harmful substances by the combined action of the jet blown from the air outlet and the backflow in front of the suction outlet.

5. Air curtain isolation hood: an exhaust hood that uses an air curtain to isolate the airflow containing harmful substances from the clean air.

6. Air supplement hood: The air supplement device is used to directly send the outdoor air to the exhaust hood at the exhaust port, such as supplement air type exhaust cabinet.

The above is a brief classification of exhaust hoods.

In actual use, it is necessary to fully combine the actual situation of the site, select a suitable exhaust hood, and install it according to the production requirements and installation requirements. The hood works effectively.