Publish Time: 2021-12-22 Origin: Site
Fume hood is an indispensable kind of laboratory furniture. It has the function of exhausting and ventilating in the laboratory. Various toxic and harmful gases, odors, moisture, flammable, explosive, and corrosive substances will be produced during the experiment operation. In order to protect the safety of users and prevent the diffusion of pollutants in the experiment to the laboratory, the source of the experimental pollution Fume hood equipment was added nearby. In the past, the number of fume hoods was small, and it was only used in experiments that generate a lot of heat and particularly harmful and dangerous gases. The fume hood is only responsible for the auxiliary functions of the experimental bench.
In recent years, considering the improvement of the experimental environment, the experiments carried out on the experimental bench have gradually been transferred to the fume hood, which requires the most suitable function for the use of equipment in the fume hood. In particular, most newly-built laboratories require air-conditioning, so the number of fume hoods used must be included in the air-conditioning system plan in the preliminary design stage of the building. As fume hoods occupy a very important position in the biochemical laboratory, the number of fume hoods used has increased dramatically in terms of improving the laboratory environment, improving labor sanitation conditions, and improving work efficiency.
Fume hoods can be classified into three types according to the exhaust method: upper exhaust type, lower exhaust type and upper and lower exhaust simultaneously. In order to ensure uniform wind speed in the experimental area, the lower exhaust type should be used for the experiments that produce cooling during the experiment or the experiment itself is operated in a low temperature environment, and the upper exhaust type should be used for the experiments that generate heat or require heat during the experiment. In the process of unstable heat, the upper and lower exhaust outlets can be set up and down to adjust the ratio of the upper and lower exhaust air volume with the change of the heat generated in the cabinet, so as to obtain a uniform wind speed.
Fume hoods are also divided into three categories according to the way of air intake. It is called the full exhaust type, which is a type that is widely used. According to the classification of the fume hood, it can be divided into integral lower part open type, floor type, two-sided type, three-sided glass type, desktop type, conjoined type, as well as radioactive experiments and synthetic experiments designed according to different experimental use needs. , Special fume hood for perchloric acid experiment. Safety is the greatest mission pursued by fume hoods. The use of fume hoods in laboratories is to ensure the safety of users and prevent pollution to the surrounding environment.
1. Before the start of the experiment, it must be ensured that the fume hood should be in operation before the experiment can be carried out.
2. After the experiment, the ventilator can be turned off after at least 5 minutes of continuous operation to ensure that the residual gas in the ventilation duct can be discharged from the duct. The exhaust time delay device can also be installed in the fume hood to ensure the delayed operation of the ventilator.
3. During the experiment, no material can be placed in the glass window 1500mm. Large-scale experimental equipment must have sufficient space, which should not affect the air flow. The front window should be closed as much as possible.