Cause Analysis and Solution of Vibration in the Operation of Screw Conveyor


The speed required for the screw conveyor is higher,if the revolving speed of the rotor is not selected properly or the rigidity of the spiral is insufficient or the balance of the spirals is poor, the vibration will be generated during operation, not only for its conveying capacity, power consumption, mechanical efficiency, material breaking rate, screw blade wear and other work performance have a greater impact, even when the serious can not work. Let us analyze the causes of the vibration of the screw conveyor and find out the corresponding solution.

For the inclined screw conveyor, the vibration of the screw conveyor is related to the speed designing,in order to avoid the direct friction between the screw blade and the inner wall of the casing, it is necessary to use the hinge support at both ends of the screw conveyor,if vertical lifting, it is appropriate to use one end of the fixed, one end of the free type.We know that when the angular velocity of the screws is close to its natural frequency, strong vibrations will occur,when the angular velocity of the screws is equal to the natural frequency, resonance occurs. The resonant rotational speed of the screw conveyor is: if the rotation speed of the screw body is close to the resonance speed, the strong vibration will destroy the steady flow of the material, which will lead to the disturbance of the material, the gap between the feedstock and the screw blade(screw conveyor part) and the casing so that the conveyor capacity and mechanical efficiency of the screw conveyor will be reduced and the power consumption will increase.At the same time, the crushing rate of material between the screw blade and machine will increase,and when the vibration of screws is multi-waveform vibration, the material flow within the machine will also be affected , increase the crashed rate,therefore, the rotation speed of the screw body should not be too high, so it will make the speed and shaft rigidity(shaft diameter) design of the rapid screw conveyor more reasonable, to avoid the design and manufacture of the screw conveyor to produce a strong vibration phenomenon, to improve its work performance.In order to solve these problem,we can according to above analysis,we can adopt below solution.

(1) Adjusting the rotary speed, make it be far away from the resonance zone.
(2) Reducing the length of the screw body. Resonance speed and spine length inversely proportional to the square.
(3) Setting the middle support,it has a similar effect with reducing the length of the screw,but the calculation of its resonant speed is slightly more complex,however, this measure is a convenient and effective method, for example,the screw conveyor in the cereals industry, if reduce the speed,it will affect the capacity,if increase the speed, it will causing food damage rate and power consumption increased. Therefore, usingmiddle support, to keep the other design parameters unchanged, so that the calculation length reduced a half, the result of the original violent vibration into the vibration can not feel.
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