How does the Fume Hood exhaust
Fume Hood is a kind of local exhaust equipment in the laboratory, because of its different structure, the use of different conditions, the exhaust effect is not the same. The good performance of the Fume Hood depends mainly on the speed of movement of the air through the Fume Hood. The speed of movement depends mainly on the power of the fan, the length of the exhaust pipe and the exhaust pipe thickness and so on.
The biggest purpose of using the Fume Hood is to discharge the harmful gases produced in the experiment to protect the health of the experimenter, that is to say that there is a high degree of safety and superior operability, which requires the Fume Hood to have the following functions:
(1) Release function: It should be provided with a mechanism for removing harmful gases from the inside of the Fume Hood with the outside of the absorber and allowing it to be removed from the outdoor unit.
(2) isolation function: in front of the Fume Hood should not slide the glass window to separate the inside and outside the Fume Hood.
(3) Supplementary function: There shall be a passage or replacement device for the inhalation of air from the Fume Hood when the harmful gas is discharged.
(4) heat and acid corrosion function: some of the Fume Hood to place the electric furnace, and some experiments produce a large number of acid and alkali and other toxic and harmful gases with a strong corrosive.
(5) does not return to the function: should have a dust inside the Fume Hood generated by the exhaust gas from the inside of the Fume Hood does not reverse the flow into the room function. To ensure the realization of this function, a Fume Hood and a fan with a single pipe connection is the best way, can not be connected with a single pipe, and only the same room can be connected with the same room, the fan as much as possible Installed at the end of the pipe (or at the top of the pipe).
(6) to control the wind speed function: In order to prevent the escape of harmful gases within the Fume Hood, need to have a certain rate of suction. The factors that determine the rate of inhalation of the Fume Hood are: the amount of heat generated by the experiment and the relationship with the number of ventilation. The main thing is the experimental content and the nature of the harmful substances. Determine the wind speed must also pay attention to the noise problem, through the air flow in the pipeline to 7-10m limit, more than 10m will produce noise, usually laboratory (indoor background noise level) noise limit of 70dBA, increase the pipeline area will be Reduce the wind speed, also reduce the noise, taking into account the pipeline funding and construction problems, you must carefully select the pipeline and the exhaust fan power. Fan power and air volume is mainly dependent on the size of the Fume Hood and the length of the discharge pipe calculated.