The laboratory constant speed exhaust system mainly consists of ventilation ducts, ventilation equipment, ventilation terminals, and ventilation systems.
There are two ventilation methods for chemical laboratories, namely local exhaust and full room ventilation. Local exhaust is a feasible and economical method for improving existing laboratory conditions, and may also be the best way to adapt to new laboratory ventilation construction, as it can immediately discharge a large amount of harmful substances nearby with less air volume, saving energy and achieving good results. For some experiments where local exhaust cannot be used or cannot meet the exhaust requirements, full room ventilation should be used.
A fume hood is a local exhaust device in a laboratory, and its performance mainly depends on the speed at which air moves through the fume hood. The factors that affect the forward speed and air movement are eddy currents, the shape of the cabinet inlet, thermal load, mechanical action, exhaust hole design, and anti condensation materials. In addition, Shangding's fire resistance, corrosion resistance, ability to clean and collect certain pollutants before entering the exhaust system are all related to his performance. It is generally believed that fume hoods in laboratories should be able to accommodate flammable liquids and gases, and the structural materials should have a fire resistance of several minutes to maintain the integrity of the fume hood and promptly extinguish the fire.
There are five main technical requirements for the laboratory constant speed exhaust system
1. The dust collection capacity of the fume hood is constant at 0.5m/s
2. Differential pressure control in the laboratory, implementing negative pressure reference values (-5~10Pa) with adjacent rooms
3. Control the frequency of the fan to achieve energy-saving effect
4. Precise temperature and humidity control, control range:+1.5 ° C, humidity of 60%,+5% variation range
5. Remote control, closely connecting the laboratory control system with the building
6. Exhaust gas purification treatment
Arrange and select according to the process requirements, usually with a wake-up frequency of 20-30 times or more
The ventilation adopts a brand new air system, and the exhaust of the fume hood does not circulate indoors. Due to the laboratory's requirement for negative pressure in the room relative to other auxiliary areas.