Mill Mill Mill

Mill   First, an overview :       In the grinding process is the most important equipment ball mill, using VVVF drive, which is still present on the blank . The reason is that the rotational speed of the cylinder mill work is constant , even if changes in range is not large . Mill electric drive way , three-phase AC squirrel cage induction motor - hydraulic coupling - gear reducer - Pulley reducer , or three-phase AC squirrel cage induction motor - gear reducer - Pulley reducer , general mill barrel as a reducer pulley used. When mill heavy start , if no transmission link hydraulic coupling , even with auto decompression starter or star - delta starter , the grid will cause greater impact, and often difficult to start . To cushion the impact of start-up , the transmission link is added to the fluid coupling , which can start smoothly ball in any state . Second, the critical speed of the ball mill and the best working speed      The speed of the ball mill grinding process directly affects the movement of the ball and the material conditions and materials. At different speeds, the ball movement and position of the cylinder body of the different materials and if the speed is low , the ball and the cylinder wall with increased material when the material and the ball is equal to or greater than the natural angle of inclination angle, the ball slide along the slope , can not form a sufficient gap, the role of the ball on the ground the material is very small, this situation is very low efficiency . If the high speed of the cylinder , due to centrifugal force , so that no material from the tube wall and the ball , and rotates together therewith. This state produces the minimum speed is called the critical speed. At this time the ball did not hit role , only slightly abrasive materials , the efficiency is very low. When the speed of the cylinder between the two is , the ball was taken after a certain height along the parabola fall. At this point the ball on the barrel end of the material to produce a strong knock-on effect , for maximum efficiency . Maximum efficiency when the speed of the work to be the best working speed .      The electrical power consumption of the ball mill motor speed is proportional to the primary side , and therefore , with the frequency of the fundamental frequency of the motor speed can be adjusted less energy range , the magnitude of energy related to the speed . Depending on the circumstances of different mediation range, 0 to 11% energy saving between the magnitude of frequency control theory . Third, the motor efficiency      A motor for the mill 90kW, during normal operation the motor current is 80 ~ 110A, load rate 62% . Since the load is not high, but also reduce the efficiency of the motor . During normal operation, the motor power does not exceed 55kW, taking into account the ball is heavy start , in order to ensure a smooth start is appropriate to increase the capacity of the motor necessary . On the surface , it seems that there is a large saving space. In fact , when the ball does not affect productivity , such as the use of frequency control , the output frequency is still 50Hz, even when the need for speed, it is impossible to regulate , reduce the frequency of a wide range of small-scale , limited energy savings . Now drive generally have " energy-saving operation " function under conditions of constant operating frequency converter automatically adjusts its output voltage, the motor efficiency is improved. Fourth, energy-saving motor regulator      As mentioned above, the motor is lightly loaded regulate the supply voltage available way to improve efficiency, calculated by the oversight Guide GB12497 " three-phase asynchronous motor economy " mandatory national standards      Thus , the frequency energy ball mill energy saving operation is limited , because the high efficiency of the motor itself , the rated efficiency of 93.5.5 % , the voltage regulator can reduce the copper loss and iron loss and stray loss , it is only reduced , and a larger proportion of the total loss of mechanical friction losses essentially unchanged, so the motor efficiency is limited, as in this example saves the active 0.27 (kW), the saving rate is very low. However , after the installation of the inverter , the efficiency of the inverter is not 100% , but this is not only not saving energy . For the transformation frequency 50Hz operation or a request for equipment , whether it is a constant torque load characteristics , or fans, pumps squared torque load characteristics , just does not make sense to consider energy conservation . The purpose of reform should be to increase the performance of the equipment and to enhance the level of automation equipment , so that not only improve productivity and product quality can be guaranteed. Such condition in the actual production abound, such as tile and cement mill plant , the rotational speed of the cylinder is determined by the calculation or experimental data , typically 16r/min ~ 18r/min, the speed deviation from the impact mill efficiency will be different Therefore even if such machinery and equipment installed on the drive and the original operating speed if there is no saving at the same speed . Fifth, the fluid coupling and frequency conversion energy conservation      Fluid coupling is achieved by controlling the moment of momentum changes in the working chamber of the working oil to the energy transfer of the motor , the motor through the fluid coupling the input shaft dragging its initiative to work round the oil accelerated the work , the work was accelerated oil work and then drive a turbine driven hydraulic coupling , and the transfer of energy to the output shaft and the load. There are variable speed hydraulic coupling and constant filling of the points, the former governor for electric drive , which is used to start the motor . The hydraulic coupling system from a buffer when the motor starter , the efficiency of the theoretical value of 95% , the efficiency of the inverter is 96 %, that is , remove the fluid coupling in the transmission link, AC variable frequency speed control mill drive motor , ball mill can start smoothly at rated current or slightly higher than the rated current, and , in theory, the efficiency can be increased by 1 %. Indeed fluid coupling efficiency and fuel injected fluid coupling cavity relevant during operation, the fluid coupling of a certain temperature , the presence of a leak Mifengbuyan other factors, its efficiency is generally less than the theoretical value of 95 %.      Scene, local compensation capacitor , the power factor is relatively high, with a compensation capacitor in place after removing the drive , the drive itself, due to the high power factor, therefore , little change in the power factor of the system . Thus, the saving rate should be around 5% , plus 1% of the previous total of 6 % ​​energy saving . VI Summary :      The current energy-saving ball mill from the above three aspects to consider , adjust the speed according to the actual work situation , in theory, 0 to 11 % energy savings ; regulate the use of the inverter power saving mode has less energy ; using the fluid coupling in the transmission link, remove fluid coupling inverter saving rate of 6 % ​​shows that the use of integrated energy conservation measures, mill frequency transformation can still achieve a certain energy saving.   <a href="http://www.finegrindings.com/solution/mining/m-sand-manufacturing-machine.html">M Sand Manufacturing Machine</a>   <a href="http://www.finegrindings.com/solution/construction/iron-ore-mining-equipment.html">iron ore mining equipment</a>   <a href="http://www.finegrindings.com/solution/production-line/iron-ore-beneficiation-plant.html">Iron Ore Beneficiation Plant</a>   <a href="http://www.finegrindings.com/solution/mining/copper-mining-process-plant.html">Copper Mining Process Plant</a>   <a href="http://www.finegrindings.com/solution/construction/artificial-sand-making-machine.html">Artificial Sand Making Machine</a>