Acid Digestion Duct Fume Hood for Professional Laboratory

A fume hood is typically a large piece of equipment enclosing five sides of a work area, the bottom of which is most commonly located at a standing work height.

Two main types exist, ducted and recirculating (ductless). The principle is the same for both types: air is drawn in from the front (open) side of the cabinet, and either expelled outside the building or made safe through filtration and fed back into the room. This is used to:

• protect the user from inhaling toxic gases (fume hoods, biosafety cabinets, glove boxes)
• protect the product or experiment (biosafety cabinets, glove boxes)
• protect the environment (recirculating fume hoods, certain biosafety cabinets, and any other type when fitted with appropriate filters in the exhaust airstream)

Most fume hoods for industrial purposes are ducted. A large variety of ducted fume hoods exist. In most designs, conditioned (i.e. heated or cooled) air is drawn from the lab space into the fume hood and then dispersed via ducts into the outside atmosphere.

The fume hood is only one part of the lab ventilation system. Because recirculation of lab air to the rest of the facility is not permitted, air handling units serving the non-laboratory areas are kept segregated from the laboratory units. To improve indoor air quality, some laboratories also utilize single-pass air handling systems, wherein air that is heated or cooled is used only once prior to discharge. Many laboratories continue to use return air systems to the laboratory areas to minimize energy and running costs, while still providing adequate ventilation rates for acceptable working conditions. The fume hoods serve to evacuate hazardous levels of contaminant.

To reduce lab ventilation energy costs, variable air volume (VAV) systems are employed, which reduce the volume of the air exhausted as the fume hood sash is closed. This product is often enhanced by an automatic sash closing device, which will close the fume hood sash when the user leaves the fume hood face. The result is that the hoods are operating at the minimum exhaust volume whenever no one is actually working in front of them.

1. Easy to assemble; Anti-corrosion and high temperature resistance;
2. Unique down return air, timely and effectively exhaust without residual;
3. Special flow-equalized design makes the flow even without any blind angle;
4. The internal visual range will not form condensate due to temperature difference, therefore no drip will form;
5. The internal airflow direction is not affected by the volume of the exhaust air, thus will not cause turbulence;
6. Low energy consumption, easy to operate;
7. Has air compensation channel and connection, saves energy, comfortable;
8. Drainage will not be limited by the height of the drain,since it has pump to lift the sewage;

 

How a Fume Hood Works

A fume hood is a ventilated enclosure in which gases, vapors and fumes are captured and removed from the work area. An exhaust fan situated on the top of the laboratory building pulls air and airborne contaminants through connected ductwork and exhausts them to the atmosphere.

Depending on its design, the sash may move vertically, horizontally or a combination of the two and provides some protection to the hood user by acting as a barrier between the worker and the experiment.

The slots and baffles within the hood direct the air and, in many hoods, can be adjusted to allow the most even flow. It is important to prevent the baffles from becoming blocked, by excessive material storage or equipment, since this significantly affects the exhaust path within the hood and as a result, the efficiency of hood capture. 

The beveled frame around the hood face, called the airfoil, allows for even air flow into the hood by eliminating sharp curves to reduce turbulence.