Types of fume hoods and common misconceptions in their use

A fume hood, also known as a fume hood or fume hood, is a kind of safety backup equipment in the laboratory, which is used to reduce the contact between the inspector and toxic and harmful smoke during the experiment, and provides a safe operation space for the inspector. The main advantages of the fume hood: the harmful gases in the experiment are discharged from the outdoors, and the air can be replenished by itself, and the wind speed can be freely adjusted according to the actual situation of the experiment to achieve the best effect.

Types of fume hoods

1. General-purpose type

Suitable for general chemistry laboratories.

2. No pipeline type

The built-in high-efficiency activated carbon filter has zero polluted air emission and purifies the air in the laboratory.

3. Replenishment air type

Replenish air from outside to reduce the load on the laboratory air conditioner.

4. Siamese type

Expand the experimental space and provide convenience for large instruments.

5. Two-sided type

It can be operated on both sides.

6. Desktop type

A fume hood mounted on a lab bench.

7. Floor-standing type

Suitable for large experimental setups.

Common misconceptions about the use of fume hoods

Is it safe to experiment in a fume hood?

NO!

It's not just safe to experiment in a fume hood.

Here is a summary of the common misunderstandings in the use of fume hoods:

1. Can I adjust the height of the fume hood window arbitrarily?

Of course, this is not right, the distance between the fume hood window and the table surface is also the best range, the fume hood window is 100~150mm away from the table top during the experiment, and the distance between the operator and the adjustment door should be kept above 150mm, and frequent movement should also be avoided, and large actions should be carried out in front of the adjustment door.

2. Is the greater the wind speed of the fume hood, the better the effect?

We generally think that the higher the wind speed, the better, but this is not the case. It is very important to have a wind speed between 0.5~0.75m/s. When the surface wind speed is higher than 0.75m/s, the vortex will be generated, which is easy to cause pollutants to escape from the laboratory fume hood, increasing the damage to the operator, and when the wind speed is between 0.5~0.75m/s, the safety factor is the highest.

3. Can I store items in a fume hood?

It depends on the specific situation, if it is an explosive, flammable or toxic and harmful substance, long-term storage in a fume hood will not only pose a threat to personal safety, but also increase the safety risk of the laboratory. When some items necessary for the experiment need to be stored, try to place them on the left and right sides and away from the source of contamination. Items or equipment that will protrude out of the cabinet, obstruct the opening and closing of the adjustment window, or block the opening under the deflector are not allowed.

4. The fume hood closes immediately after the end of the experiment?

Of course, this is also a no-no, the exhaust gas in the window needs to be run by the exhaust fan for a few minutes before it is completely discharged. After the exhaust gas is thoroughly discharged, wipe the inside and outside of the cabinet to clean, and close the switches and windows.