What to pay attention to when installing fume hood air exhaust system

First, the laboratory fume hood-fan selection:

 

The installation of laboratory fume hoods generally uses two types of axial flow fans and centrifugal fans. DC exhaust fans are generally used in laboratory exhaust ducts. Centrifugal fans are recommended for pipes longer than 10 meters. The resistance of the wind is naturally large when the pipes are long. Larger, the air volume is also larger, you have to use a centrifugal fan. The general fan material is pp material and glass steel material.

 

Second, the laboratory fume hood-fan installation:

 

1. The foundation of the laboratory fume hood-fan is required to be horizontal and sturdy, and the foundation height is ≥200mm.

 

2. The steel bracket of the laboratory fume hood-fan must be fixed on the concrete foundation. A rubber damping pad must be added between the steel bracket of the laboratory fume hood-fan and the foundation. All the fan and motor components are installed on a monolithic steel bracket, and the steel floor frame is installed on the vibration damping pad on the top of the foundation. The vibration damping pad uses a porous rubber plate.

 

3. The pipe diameter of the fan outlet can only be enlarged and cannot be reduced. An insect-proof net should be installed at the air outlet, and a rain cap must be added when the air outlet is upward.

 

4. Laboratory fume hood-The fan and the air pipe are connected by hoses (flexible materials and do not burn), the length should not be less than 200mm, and the pipe diameter is the same as the size of the fan inlet and outlet. To ensure that the hose does not distort during the operation of the system, the installation should be moderately tight. For the canvas hose installed on the suction side of the fan, it can be installed a little tighter to prevent the fan from being sucked in during the operation and reduce the cross-sectional size of the canvas hose.

 

Third, laboratory fume hood-air duct bracket installation precautions:

 

1. All bolt holes on the air duct bracket are drilled, and gas welding cut holes are not allowed;

 

2. For brackets with inclined support, the welding seam should be full;

 

3. No other professional pipes or cables can be installed on the air duct support.

 

Fourth, the attention of concrete foundation construction:

 

1. Before pouring concrete, civil engineering should check the position of the foundation, the elevation of the top surface of the foundation, the geometry of the foundation, the position and depth of the bolt holes reserved, and the elevation of the foundation surface should not have a positive error (that is, it should not be adjusted) Out design elevation).

 

2. The depth of the foundation buried below the ground should be constructed according to the design requirements, generally not less than 50mm, the concrete should be dense, the outer surface should be smooth, and the concrete strength grade should meet the design requirements.

 

3. After the fan is fixed, the secondary grouting anchor bolt holes should be performed. Bean stone concrete should be used for the second grouting, and the holes should not be filled with cement mortar.

 

4. The blanking of the boom in the hanger should be accurate, and there should be no overlap welds in the middle of the boom;

 

5. When the cross section of the air duct is small, the air duct boom can be fixed on the floor with expansion bolts. When the air duct is large, it should be fixed by drilling;

 

5. Before installing the bracket, the centerline of the air duct should be popped up on the wall, column and floor, and then the horizontal position and elevation of the bracket should be determined to ensure the horizontality and plane center position of the air duct after installation;

 

6, before the installation of the bracket, the exposed part should be derusted and brushed with anti-rust paint;

 

7. When there is no special requirement, the distance between the air duct brackets of the fume hood is generally 3m, but in the air duct less than 3m, one bracket should be installed at each end, and brackets should be installed at the tee and elbow.