Dynamic Design and Computer Imitation of Belt Conveyor with Horizontal Curves

The dynamic design of a large belt conveyor with horizontal curves was studied in this paper. The method of calculating its running resistance was obtained by analyzing the orienting force and resistance on the curving parts of the belt conveyors. Dynamic equation of belt conveyor with horizontal curves by using discrete finite element model was established integrating the line-running parts and the curve-running parts. Additionally, dynamic analysis software of belt conveyor with horizontal curves was developed. Through simulation on real time system, start-up process and braking process were analyzed. The deviation of the belt was analyzed based on the tension, and the effect of curve running on belt conveyor was discussed.


Introduction
Because of the limitation of buildings or landform, the long distance belt conveyor may include horizontal curves.By setting idlers roller inclined forward, raising the inner curves, and increasing the groove angle, the natural orientation of the belt conveyors can be achieved.Up to now dynamic of long distance belt conveyor systems has been researched [1] [2] [3] , but the research on the dynamic of belt conveyors with horizontal curves is comparatively scarce.It gives the force analysis of the curve parts, deduces the calculating method of resistance, establishes the dynamic equations, develops the dynamic analysis software, simulates the real time system and then analyzes its results in this paper.The most effective centrifugal thrust force is produced by the gravity of belt and materials.The direction of the centrifugal thrust force is pointing to the outer curve; the groove angle of the idlers was increased as shown in fig. 1.The inner of the idlers will be inclined along the moving direction of belt shown as fig2.

The structure of the horizontal curves
is satisfied, the belt will not deviate to the inner curve.

The running resistance calculation of the belt of the horizontal curves
The running resistance includes the major resistance, the inclining resistance and the forwardinclining resistance of the idler.The resistance calculation process of the curve-running part can adopt the standard method [5] .Assuming the curve of the belt is circular arc, and supported by three idlers, as shown in fig. 3. ) .Because the centrifugal inertial force is very small of the curves, it can be ignored.Aiming at the distance between adjacent idler units, according to the force analysis of fig. 3 ) sin( ) cos(

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Mechatronics and Information Technology

Building up the dynamic equation of the belt conveyor with horizontal curves
Belt conveyor with horizontal curves was divided in discrete finite units.The dynamic equation of the system is the integration of line-running parts, curve-running parts, drive unit and tension device.In this paper the emphasis is curve-running parts, and others can refer to reference [5] .Aim at the unit i of curve-running parts.For this unit the arc is l , the radius is R , so the corresponding central angle is Adding other parts of the system the dynamic equation of the whole system can conclude The simulation on real time system By the Wilson θ method the dynamic equation was solved.Using Visual Basic 6.0 the software was developed.Using the software the 8000m belt conveyor with 2 horizontal curves was analyzed.
The results are as follows:   .Therefore, the fully loaded belt will not deviate to inner curve in the curve-running part.But it maybe deviates to the outer curve.In this case, vertical idlers will be adopted at outer curve.Then the belt conveyor will run normally.

Fig. 1 .
Fig. 1.The structure of superelevation angle in Fig. 2. Mechanical model of the belt at inner curve and trough angle of the idlers the horizontal curve

Fig. 3 .ρ
Fig. 3. Forced graph of the belt at the horizontal curveThe arc distance between two idler units is 0 a , the radius of curvature is 0 ρ , so the shown in fig.4.So the dynamic equation of unit i :

Fig. 4 .
Fig. 4. Mechanical model of the unit i in horizontal curves

Fig. 5 . 3 Fig. 7 .
Fig. 5. Velocity curve of the belt of tart-up process Fig. 6.Tension curve of the belt of tart -up process