Both fume hoods and universal exhaust hoods are used as equipment for laboratory ventilation, but the scope of use of the two is different. The fume hood plays a role in controlling and discharging polluting gases. Other exhaust equipment, such as universal suction hood and atomic absorption hood, also have exhaust functions, but they cannot control the direction of the air flow well, and cannot isolate the polluting gas and prevent the function of polluting gas overflow.

1. The universal exhaust hood is mostly installed above the experimental table. When the experiment is carried out, the moving arm of the universal exhaust hood can be moved to directly cover the cover directly above the experimental position, which can ensure that the polluting gas can be absorbed and discharged smoothly.

The advantage of the universal extraction hood is that it is flexible, movable, and able to move arbitrarily within the maximum radius. The disadvantage of the universal extraction hood is that the absorption area is not large enough to completely absorb harmful gases, so the safety is poor.

2, the fume hood is placed directly in the laboratory somewhere, when it is necessary to use, open the fume hood, and then transfer the experimental environment to the fume hood cabinet body, because the inside of the cabinet is isolated from the outside world, so when the fume hood works, the polluting gas will be firmly controlled inside the cabinet, while discharging the polluting gas, it also avoids the contact between the polluting gas and the outside world.

The advantages of the fume hood are isolation and discharge effect, and because the experiment is carried out directly inside the fume hood, it plays a protective role for the experimenter. The disadvantage of the fume hood is that the equipment occupies a larger position and cannot be moved at will, which is more rigid and flexible to use.

3 The performance characteristics of the universal exhaust hood:

1. The material is composed of high-density PP, which is acid and alkali resistant and corrosion resistant;
2. Large range of motion, can be centered on the fixed frame, with 1440mm as the radius of 360 degrees of rotation; The height stroke can be freely retracted and positioned within the range of 720mm;
3. The distance between the decorative fixing seat and the bottom surface of the fixing frame is adjustable, and the adjustable range is 990mm~1450mm;
4. With airflow adjustment button, can control the gas flow;
5. Easy to use, easy to disassemble, reassemble and clean.

Second, the universal exhaust hood installation and use
1. According to the workplace and indoor environment, select the installation position of the exhaust hood, punch the hole in the ceiling according to the fixed seat hole, and fix the fixing frame to the ceiling with M8 expansion screws;
2. Insert the telescopic tube into the exhaust pipe hole of the fixing frame, lock the telescopic pipe with the exhaust pipe with the pipe hoop, and position the decorative coil tightly;
3. Tighten the gas collection cover;
4. Connect the exhaust outlet, connect the exhaust outlet with the exhaust air system;
5. When using, you can pull the gas collection cover at will, align it with the exhaust point, and adjust the flow adjustment button. With the rear rotation knob, close the wind deflector and fold the gas collector to reset.

Third, the universal exhaust hood installation and use precautions:
1. There are pressure bearings and rubber rings in the joint, if the joint is loose, the joint knob can be tightened appropriately;
2. Do not push and pull the gas collection cover too hard;
3. The telescopic tube and the fixing frame should not exceed 90 degrees in the vertical plane, otherwise it will rebound;
4. Installation height, ceiling and suction port vertical distance of up to 2440mm, minimum 1710mm.