Cooling Systems Axial Exhaust Fans Industrial Low Noise Bifurcated Axial Fan

Axial exhaust fan low noise high efficiency industrial axial flow fans bifurcated axial fan

The impeller for axial exhaust fanis one of the main components of the axial flow fan. The gas can obtain energy through the rotation of the impeller, and then leave the impeller for the axial movement of the spiral line.
The industrial axial fans impeller is composed of moving blade, hub, petiole, bearing and balance weight hammer.
Many blades of the same airfoil are arranged into a group of blades with equal distance from each other, which is called a cascade. The axial flow fan is equipped with blades on the hub to form a ring cascade. The height of the flow through part of the blade of the axial flow fan is larger than that of the ventilator, which can ensure that the smoke volume of the induced draft fan is larger than the air supply volume.
The rotor blade of the axial flow fan is twisted. The whole blade is twisted to a certain Angle along the radial direction, and the blade width and thickness are gradually reduced along the wing span direction of the blade. We have stated previously that in order to make the energy heads produced by all sections of the fan blades with different radii the same, that is, the velocity loops on all sections are equal. Therefore, the blade radius near the hub is small, the grid distance is also small, and the circumferential velocity also decreases. In order to make the velocity loop equal to the blade top, it is bound to increase the blade root installation Angle and blade chord length, so the blade is made into a spatially twisted shape. Of course, the width and thickness of the blade along the wingspan direction is reduced, which can also reduce the centrifugal force generated by the blade, do not make the petiole and thrust bearing force is too large, and ensure the blade strength.
Axial fan blades made of twisted shape, its efficiency is also higher, less loss. Because the impeller rotates, tip speed is greater than the circumference of the hub and peripheral speed of wind pressure big, small peripheral speed of wind pressure, so that in the runner blade along the blade of radial flow of energy is not equal, so produced from the tip to the flow of the blade root part, forming axial vortex energy loss. And make the blade into a twisted shape, blade root blade installation Angle is larger, then the wind pressure can be increased; On the contrary, the blade at the tip of the blade installation Angle is smaller, the wind pressure can be reduced. The blade mounting Angle at the blade root is larger, but the circumferential velocity is smaller. The blade installation Angle at the blade tip is smaller, but the circumferential velocity is larger. These two factors restrict each other, so that the wind pressure generated at the blade tip and blade root is almost equal, and axial vortex is avoided.
The surface of the moving blade of the axial fan is required to be smooth, which can reduce the friction loss of the air flow and the separation loss caused by the flow off the airfoil surface. The root of the blade is bolted to the petiole, and the blade and petiole are placed into a circular hole in the hub, and then fitted with counterweight blocks, support bearings, guide bearings, safety rings, safety plates and adjusting rods. The supporting bearings of axial flow maneuvering blades are subjected to the centrifugal force generated by moving blades and petioles. The guide bearing on the moving blade, because the moving blade and petiole are longer, the guide bearing is to ensure that their center is not skewed, and the guide bearing can also bear a certain centrifugal force. In order to make the moving blade can rotate flexibly when adjusting, guide the bearing and support. Bearings are made of ball bearings with low friction.
The leaf stalk of each moving blade is equipped with a balance weight block, and the center line of the balance weight block is almost perpendicular to the airfoil plane of the moving blade. Its function can balance the large closing moment generated by the moving blade, so that the moving blade can also move quickly when rotating.
In order to ensure sealing and lubrication, lubricant is injected in the guide bearing and the supporting bearing, and grease is also filled in the gap between the petiole and the hub.
The radial gap between the moving blade and the shell is required to be less than 3mm. This gap can not be too large, otherwise it will cause large air leakage loss and reduce the efficiency of the fan.
In order to ensure the dynamic balance of the whole impeller, when replacing the blade, the same weight of the blade can be placed in a symmetric position, and balance check.
The moving blade housing is a steel welded housing, and the inspection hole is provided on the housing, which can check, remove and install the moving blade. The upper part of the fan enclosure is removable for quick loading and unloading of the impeller.

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