圆锥破碎机磨损模型英文文献和中文翻译(4)

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factor f in Eq. (5) is small, since the angle between the liners is small.

2 shows the measured and simulated wear on an H6800 mantle. The wear is computed as the difference between nominal new and worn geometry, measured in the normal direction of the surface. As can be seen in Fig. 12, the new wear model signiﬁcantly improves the wear prediction in the upper part of the crushing chamber compared to the old model. The ﬂow model used here was presented by Lindqvist .

Fig. 13 shows simulated and measured wear on the concave of a worn SANDVIK H3000 MF chamber. The measurement in Fig. 13 was made by Lindqvist and Evertsson. Highly abrasive quartzite was crushed. The simulation in reference was made with the ﬂow model presented by Evertsson . That model is slightly different from the one used here. Fig. 12 shows the wear on the mantle of a Sandvik, H6800 crusher, Fig. 13 shows the wear on a Sandvik H3000 MF concave. The mantle and the concave have different local coordinate systems in the simulator, hence the difference in y-coordinate.

3.3. Simulation versus measurement of operating parameters

Hydroset pressure and power draw were read off the control panel of the crusher once every day. When the inlet bin of the crusher is entirely ﬁlled with rock material, the crusher is said to be choke fed, and this is the preferred way to operate a cone crusher. Readings were taken during normal operation of the crusher, i.e. choke fed conditions. The feed was between 32 and 250 mm and came from the primary crusher.

The wear model is indifferent to how time is scaled, and the wear rate is exaggerated in the simulations, to save computation time. The wear was accelerated by a factor of 4700 times,as compared to the wear rate found by Lindqvist and Evertsson . If the wear rate is accelerated too much, the simulated worn geometry will deteriorate as compared to the measured geometry.

Fig.14 shows the correlation between power draw and hydroset pressure. The model for ﬂow and crushing pressure require a validation of some model parameters . In the simulations made here, the model parameters were selected so that power draw and hydroset pressure were predicted as accurately as possible with respect to average measured data. Power draw and hydroset pressure cannot be predicted accurately without taking losses into account. Losses in a cone crusher arise mainly in the electric motor, the belt drive, the roller bearings supporting the driveshaft. Frictional losses occur in the top bearing, the eccentric bushings and the spherical thrust bearing who are all boundary lubricated plain bearings. According to the machine manufacturer, this particular crusher usually has an idle power draw of 30–35 kW. The mass of the main shaft corresponds to a hydraulic pressure of 0.28 MPa. To adjust for losses, dependent and load independent losses were simply added to

the nominal data to make simulations match measured data. A constant load independent loss of 35 kW was added to the power draw and the load dependent loss was computed by piding the nominal power draw by the total efﬁciency. The efﬁciency used here was 59%. If the losses are subpided onto electric motor, belt drive, driveshaft, bevel gear and eccentric bushing, the average efﬁciency of each of these power-transmitting components will be about 90%. The two model parameters for an H3000 MC chamber that were found by Lindqvist [6] were K1 = 0.312 and K2 = 1.01. For this crusher, which is much larger, K1 = 0.3590 and K2 = 1.2387.

Readings of power draw and hydroset pressure were taken during normal chokefed conditions once every day (see Figs. 15 and 16). The time of these readings were only speciﬁed by date. The number of hours per day each crusher was in operation was recorded, and was below 8 h every day. This means there is an inaccuracy of less than 8 h as for when each read- ing was made. Simulated time has here been expressed as dates.Simulated time corresponds to the time it takes for the model to produce the same amount of maximum wear on the mantle as is measured. In other words, maximum simulated wear corresponds directly to simulated time. The maximum wear on the mantle was 48 mm in the last measurement 。