The traditional type of fume hood is externally arranged, and the toxic gas that is pumped away is directly discharged to the outside through an external pipe, which not only may cause harm to the environment, but also the fan continuously draws indoor air and consumes a large amount of air conditioning energy consumption. Cause energy waste. When installing a pipeline fume hood, it needs to go through professional laboratory planning and design, heavy layout and construction, the process is long and costly, and once the construction is completed, the modification is very inconvenient.
The ductless fume hood is equipped with a fan and a filter at the top, and the fan draws air from the bottom. The filter adsorbs and removes toxic and harmful substances in the airflow, and then the safe airflow is discharged to the laboratory, and the cycle is repeated. The ductless fume hood does not require external piping, and the non-polluting gas is discharged into the atmosphere. At the same time, there is no need to vent indoor air, which is energy-saving and environmentally friendly, and easy to move. It can be flexibly changed according to the laboratory layout. The ductless fume hood is assembled and delivered without any complicated installation process, saving a lot of time and manpower.
In terms of scope of application, traditional fume hoods do not limit the use of chemicals, nor do they limit the amount of chemicals used. These volatilized chemicals are discharged directly to the outside. The ductless fume hood uses an activated carbon filter to purify the gas. Different types of activated carbon filters are required for different chemical types. Different activated carbon filters do not have the same filtration efficiency for a particular chemical. When selecting a filter type, you need to consider the type of chemicals that will be used in the fume hood. In addition, the adsorption of the filter will be saturated, monitoring the saturation of the filter is very necessary for the ductless fume hood, when the filter is saturated, it should be replaced regularly.
The development of ductless fume hoods has been more than 30 years old, and the various technologies have become more mature. The international standards have also been set. The most stringent standard for the unpiped fume hoods in the world is the French AFNOR NFX 15-211 standard. This standard is adopted by most European countries. China's China Standard JG/T385-2012, which was released in 2012 and is about to be implemented, is also aimed at any self-circulating filter fume hood and medicine cabinet. In addition, there are other international standards such as: US SEFA 9 standard, US control concentration standard ASHRAE110 -1995, European controlled concentration standard EN14175-3. When selecting a ductless fume hood, users need to pay attention to whether the product meets these standards.
The ductless fume hood and the traditional fume hood have their own advantages and disadvantages. In the specific selection, it is necessary to take into account the actual situation of the user, such as: laboratory site, scope of application, cost budget, etc. In the end, as far as possible from the perspective of the overall situation and sustainable development ideas, choose a program that meets the long-term interests of users.
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