The ventilation design of the laboratory is different from the ventilation design requirements of the comfort air conditioning system. The main purpose of laboratory ventilation is to provide a safe and comfortable experimental environment and reduce the exposure of the experimental personnel to the harmful air environment. Solve the physical health and labor protection of experimental personnel in the experimental environment.
The laboratory plastic ductwork consists of ventilation equipment, PP plastic ductwork and air duct dampers, and ventilation control systems.
Laboratory plastic ductwork skills requirement:
①Fume hood capture and dust collection ability, to achieve a constant wind speed of 0.5m/s on the surface of the fume hood, which meets the international standard.
②Laboratory differential pressure control, implement negative pressure with adjacent rooms, reference value (-5~10Pa).
③ Control the fan frequency to achieve energy saving effect.
④Precise control of temperature and humidity, control range: +1.5°C, humidity is 60%, and the change range is +5%.
⑤ Remote control, the laboratory control system and the building are closely connected.
⑥ Exhaust gas purification treatment.
Ventilation design scheme of laboratory
(1) The laboratory selects a certain number of fume hoods according to the process requirements and functional layout, and some also have some local exhaust hoods. Usually checked, the number of air changes is much greater than 10 times, – generally more than 20-30 times, which meets the requirements of the number of air changes. However, this number of air changes is based on the ventilation
The ventilation volume calculated by the maximum open area of the cabinet, data and experience show that 100 fume hoods are only used by 18 or less people 99% of the time. Therefore, the ventilation volume and the number of air changes at the minimum opening area of the fume hood should also be checked. If it is less than the required number of air changes, increase the comprehensive exhaust system
(2) The laboratory ventilation adopts a fresh air system, and the exhaust air of the fume hood is not circulated indoors. Because the laboratory requires the room to be under negative pressure relative to other auxiliary areas. Therefore, the fresh air volume of the laboratory is designed to be 70% -80% of the exhaust air volume. Another 20% -30% of the fresh air is sent to the laboratory auxiliary room, office, management room, inner corridor, etc., and then supplemented to the room by the gap between doors and windows.
(3) The air volume balance of the fume hood can be controlled by a constant air volume control system, that is, the exhaust air volume is constant, the supply air volume and the supplementary air volume for the gap between doors and windows are constant. This method is suitable for laboratories where the maximum exhaust air volume meets the minimum air change requirements.
(4) For rooms whose exhaust air volume is much larger than the minimum ventilation volume requirement, a two-stage ventilation control system can also be used to ensure air volume balance, that is, according to the displacement signal of the fume hood, there are two air supply conditions for the exhaust fan and the supply fan. The working conditions should be used to maintain the minimum number of air changes.
about energy consumption. In this case, the drug testing institute adopted a variable air volume control system. When the air volume of the fume hood changes, the exhaust air volume will also be relatively small.
At this time, the exhaust fan placed on the roof is required to change frequency with the change of the position of the fume hood cabinet , reduce the air volume, and ensure the constant wind speed of the fume hood surface. At the same time, the automatic control system changes the frequency of the new fan, reduces the air volume, and maintains the negative pressure balance. Variable air volume systems can reduce system energy consumption. When the maximum and minimum ventilation times of the system are close, the constant air volume system is considered, which makes the system simple and reduces the initial investment.
In addition to the special requirements for fume hoods mentioned above, Plastic ductwork also has certain requirements and standards for other equipment and control systems. In addition to satisfying the air exhaust and capture capacity, the selection of the fume hood should also pay attention to the need to change the air volume immediately according to the movement of the adjustment door to maintain a constant surface wind speed.
Suggested that the measurement and control of the system air volume should be measured by the displacement of the cabinet door instead of the surface wind speed. In addition to the equipment selection factors, the design of the plastic ductwork and the control system are the key factors to ensure the response of the system.
The time should be short enough (<1 second) that the unbalanced plastic ductwork will cause the fume hood to lose the exhaust and capture capacity, the air flow out of the laboratory, and the pressure in the building will become unstable.
Laboratory plastic ductwork Maintenance
●Scope of service
Maintenance and maintenance of laboratory equipment; maintenance and maintenance of fume hoods; maintenance and maintenance of laboratory bench cabinets; maintenance and maintenance of plastic ductwork; maintenance and maintenance of laboratory equipment accessories, etc.
●Value-added services:
- Specialized in the training of daily maintenance of laboratory furniture for all personnel of the enterprise laboratory;
- Training of laboratory furniture operating procedures;
- The laboratory maintenance personnel of the selected user department] regularly maintain;
Maintenance; maintenance and maintenance of laboratory bench cabinets; maintenance and maintenance of plastic ductwork; maintenance and maintenance of laboratory equipment accessories, etc.
●Value-added services:
- Specialized in the training of daily maintenance of laboratory furniture for all personnel of the enterprise laboratory;
- Training of laboratory furniture operating procedures;
- The laboratory maintenance personnel of the selected use department regularly maintain;
