Standard laboratory fume hood and variable frequency air volume control system:

       1. Configuration and function

      The standard laboratory (three to nine floors) has designed the most simplified, inexpensive and practical fume hood constant wind speed variable frequency control system and ceiling exhaust interlock control system.

     Large laboratories with a single fume hood on the first and second floors have only designed fume hood exhaust and ceiling exhaust interlock control systems, without frequency converters and sensors.

       2. Configuration of standard laboratory fume hood and air volume control system

      Each laboratory is equipped with one fan and one frequency converter, and can be configured with up to three fume hoods, which can be arbitrarily reduced.

      Each fume hood is equipped with a displacement sensor, which automatically adjusts the exhaust air volume of the system as the opening (lifting) of the glass door is changed to maintain the surface wind speed on the front side of the fume hood substantially unchanged (wind speed is 0.5±0.1m/S). ).

When the glass door of each fume hood is closed (lower down), the electronically controlled valve of the ceiling exhaust is automatically opened, and the indoor exhaust is exhausted through the two exhaust vents on the ceiling. When the door of any fume hood is opened, the electronically controlled valve of the ceiling exhaust is closed.

      When the fan power is turned off, the air duct has a certain natural exhaust effect.

       3. Features of the constant wind speed variable air volume control system of the fume hood

     (1) The inverter is directly controlled by the displacement sensor, and no sensor is installed in the air duct to avoid corrosion and contamination of the sensor.

     (2) The air volume is directly adjusted by the lifting of the glass door (no other switches are added), and the method of use is simple.

     (3) The energy-saving effect is good, and the low-intensity exhaust can save electricity and reduce the loss of heat or cold in indoors and buildings.

     (4) When the air is discharged at a low intensity, the noise inside and outside the room becomes small.

       4. Basic technical parameters of constant air speed variable air volume control system for fume hood

      The rated power of the fan is 2200W, the rated air volume is 6000m3/hr, and the indoor air can be replaced every two minutes at full power operation.

      The air volume of the ceiling exhaust is 800 to 1100 m3/hr. The indoor air can be replaced in about 10 minutes.

The air volume of the natural exhaust of the wind tunnel is 0-60 m3/hr (related to atmospheric wind and indoor and outdoor temperature difference).

When the opening height of the ventilating cabinet door is greater than 30cm, the surface wind speed is about 0.5m/S, and when the door opening height is less than 30cm, the surface wind speed is about 1m/S.

       5. Material and performance of the fume hood

The cabinet is made of all-steel type, and the surface is electrostatically sprayed with epoxy resin (using international famous brand coatings, which has good anti-corrosion performance). The countertop is made of 20mm thick special ceramic plate, which is resistant to chemical corrosion and high temperature, and is covered with epoxy water retaining edge. The electric socket and the light switch are mounted on the outside of the frame, equipped with 10A single-phase five-hole and three-hole sockets. The small-panel of the three-hole universal socket can be inserted into the round plug. There are 1 or 2 remote water nozzles and epoxy small basins in the cabinet.