1. Structure and technical characteristics of mineral sizer crusher
1.1 Body structure mineral sizer crusher body is mainly composed of driving part, rotor part, counter plate part, adjustment part and so on.
1.1.1 Drive part of Mineral sizer crusher The drive part adopts the configuration mode of motor + mechanical coupling + soft starting system. The motor adopts domestic YKK6302-10 6kV motor with a power of 900kW, the mechanical coupling adopts the German elastic pin coupling imported with the main engine, and the soft starting system adopts the products of foreign advanced companies. The driving mode can reduce the starting impulse current of the motor, reduce the impact on the power grid and the motor itself, but also reduce the mechanical impact on the mechanical load device of the motor, prolong the service life. In addition, the elastic pin coupling is small in size, light in weight, maintenance-free, easy to disassemble and assemble, and can directly transfer the motor torque to the mineral sizer crusher, high efficiency, conducive to the performance of impact mineral sizer crusher, to ensure the crushing effect. Compared with the hydraulic coupler which is large in volume, heavy in weight, needs to be filled with oil and is extremely difficult to disassemble and assemble, it has obvious advantages. Therefore, this driving mode is the preferred configuration of large reversible hammer coal crusher.
1.1.2 Part of the rotor The effective length of the rotor is 2500mm, the diameter of the rotor is 1800mm, the linear speed of the rotor is 56m/s, and 108 hammer heads are distributed on 12 shafts and assembled in the frame. The hammer head and hammer arm are split structure and connected by the pin shaft, so as to facilitate the replacement of the hammer head. The hammer head is arranged in spiral shape in the direction of the rotor length, and the connection shaft between the hammer arm and the rotor is a piecewise structure. It does not need to pump shaft space during maintenance, and can effectively reduce the inlet and outlet air volume, improve the balancing performance of the whole maneuver, and reduce the disturbing force value of the operation. The hammer head adopts large distributed diameter and small starting torque. The rotor disc of the suspended hammer arm is a split structure, and the flexible connection between the hammer head and the hammer arm and the hammer arm and the rotor disc can play the role of overload protection to prevent debris from jamming or damaging the equipment after entering the mineral sizer crusher.
1.1.3 Counterattack plate and adjustment part The counterattack plate is suspended in the frame and is in the shape of a broken line, with one set on the left and one set on the right. The two sides are arranged symmetrically. mineral sizer crusher outlet without grate, by adjusting the gap between the counter plate and the hammer head to ensure the granularity of discharge, discharge granularity dmax≤8mm. There are two adjusting points on the upper and lower part of the counter plate. The upper adjusting point can be adjusted according to the different position of the crushing material, so as to change the size of the upper part of the crushing chamber and the impact Angle of the material on the counter plate. At the same time, the feeding particle size can be properly controlled. The lower adjustment point can change the gap between the counter plate and the hammer at any time, so as to control the granularity of the discharge.
2.1 Control System and accessories The equipment has a high level of automation, equipped with automatic monitoring system, hydraulic opening system, automatic lubrication system and vibration reduction system. The automatic monitoring system can monitor the amplitude of the host bearing seat, bearing temperature, speed, etc. The monitoring system is equipped with control software, which can be interlocked with the main control system to realize local and remote automatic control.
The hydraulic opening system is used for the opening and closing of the left and right frame during maintenance, which can effectively reduce the maintenance work intensity. The automatic lubrication system is centrally controlled by the automatic monitoring system. There are grease injection interfaces at various key positions of the fine mineral sizer crusher, which acts as the seal of the rotating parts while reducing friction and wear. The damping system adopts special composite damping damper, the damping efficiency is more than 80%, which can effectively reduce the dynamic and static load of the whole machine on the foundation and reduce the investment in civil construction.
Since the equipment was put into trial operation on October 21, 2002, up to 4.5 years of operation,A mineral sizer crusher has crushed about 2.05 million tons of raw coal in total. B Fine mineral sizer crusher crushed about 2.43 million tons of raw coal. The overall operation condition is good. The output of the equipment, the granularity of the discharge and the adaptability of the coal quality can meet the production needs, but some problems have also been exposed. Now, the operation condition of the fine mineral sizer crusher is analyzed from the following aspects.
3.1 Discharge Grain size and output analysis According to the grain size distribution curve of coal fed into the furnace provided by the boiler, the optimal grain size distribution is dmax=8mm and d50=1m. In order to cooperate with the performance test of mineral sizer crusher, during the trial operation, the power plant specially purchased large coal with a particle size of 60~ 150mm. After the crushing of two-stage mineral sizer crusher, the power plant randomly grabbed a handful of coal, which was found to be fine particles and fine powder by visual inspection. After sampling to do screening test, screening results meet customer requirements.