Ventilation is very important in various production environments, so in order to achieve better ventilation, most companies will use centrifugal fans as induced draft fans or blowers, but want to ensure smooth operation of centrifugal fans, low noise, and correct foundation construction Sex is very important, how to do the foundation of the centrifugal fan?
Basic construction requirements for centrifugal fan foundation
1. According to the weight, structure, size and force indicated on the centrifugal fan drawing, it is necessary to ensure that the installation foundation is correctly designed and the quality is reliable.
2. In order to ensure that the centrifugal fan runs smoothly and quietly, obtains good performance, and reduces vibration and maintenance costs, the installation foundation is required to be flat, solid and level.
3. The soil, stones, rocks, etc. under the foundation must be solid enough to prevent structural imbalance, and must have appropriate hardness to avoid shaking or translational vibration resonance.
4. If the centrifugal fan is installed under the support seat of the bearing through some backing plates, when making the foundation, it is necessary to leave space according to the size of the backing plate and the needs of grouting.
5. The position of the anchor bolts should be consistent with that in the assembly drawing of the centrifugal fan.
Common centrifugal fan foundation construction requirements
1. Rigid support foundation
The rigid foundation is the pouring of reinforced concrete under the centrifugal fan and all drive components. In general, when the weight of the foundation is more than five times the weight of the fan and all drive components, it can act as an inert block to help stabilize the foundation, but requires:
(1) The base layer must gradually become larger in order to avoid subsidence.
(2) The top of the foundation must be 150~180mm wider than the bottom contour of the centrifugal fan, and the edge shall be beveled to avoid breaking into small pieces.
(3) The lower limit of the weight of the opposite parts of the drive end and the base of the drive end should be equal to the weight of the wheel and axle assembly.
(4) The sides of these bases slope down from the top, at least 15 degrees, unless the drive end base is shared with the motor base, if so, the sides must be vertical.
2. Flexible support foundation
The flexible support foundation of the centrifugal fan is generally a foundation with a shared base and a shock absorber below it, which is also required in the construction design:
(1) If a structural steel foundation must be used, the steel foundation must be strong enough to ensure that the center remains unchanged after alignment. In addition to fully bearing the weight of the centrifugal fan, the design must also be able to withstand the rotating parts. Centrifugal force (usually equal to 50% of the weight of the rotating part).
(2) Centrifugal fans installed on the ground should be close to solid walls or large columns, or on top of them. Over-the-top platforms or supported objects must be level, supported firmly, and must be independently supported in any direction. Shared support with the fan, as long as it is installed on the ground, the design of the structure should allow on-site corrections (that is, diagonal bracing can be used). If the test operation shows that the firmness must be increased, diagonal bracing must be used. For many centrifugal fans installed on structural steel frames, it is recommended to install vibration isolators with springs to avoid vibration transmission problems.
(3) The shape of the anchor bolts in concrete must be L-shaped or T-shaped. They should be placed in a pipe or sheath made of sheet metal, the size of the pipe or sheath should be 50mm larger than the size of the anchor bolts to facilitate fine-tuning after grouting. The foundation must be level, leaving a space of at least 25~30mm, so that when the top surface of the foundation can be adjusted and grouted with spacers, the jacking bolts must be removed, and the bolts must be tightened before grouting. All gaps under the bottom corners of the foundation All must be filled with grout. After curing, tighten the foundation bolts, and then check again that the foundation is level.
(4) For all large centrifugal fans, the foundation should be anchored to the rock bed, and if necessary, piles should be driven. Before foundation construction, please consult the civil engineer.
Inspection and lay-out of centrifugal fan foundation
In order to ensure the smooth progress of the installation of the centrifugal fan, the installation unit should generally inspect the external dimensions of the foundation, the dimensions related to the installation, and the surface quality together with the civil engineering unit. The axis, elevation and dimensions of the foundation must meet the requirements of the architectural drawings, the plane height error is not more than 0~20mm, the vertical error of the anchor bolt hole is not more than 1/100, and the surface of the foundation must not have cavities, looseness, interlayers and other debris .
The foundation line is to correctly find and draw the installation reference line and installation construction line of the centrifugal fan, so that the centrifugal fan can be placed in the correct spatial position. Requirements:
1. The installation datum line refers to the plane datum line, the longitudinal line (axis), the horizontal line, the elevation line, and the installation construction line refer to the center line of the reserved hole for the anchor bolt.
2. Draw the frame line of the centrifugal fan base and the position line of the installation horn.
