对6.7m双螺旋卸车机控制回路的研究及改造

Research and Modification of the Control Loop of 6.7 m Double Screw Unloader

6.7米双螺旋卸车机是火力发电厂的大型卸煤设备,使用率非常高,相应的故障也很多。因绞笼的自重原因,以及操作的不规范。绞笼下降到下限位时,虽然抱闸启动了,但并不能将绞笼马上停下,时常将绞笼的下降机械限位撞坏。绞笼经常过下限位运行时绞笼与火车车厢的底板摩擦,造成绞笼的过度磨损,造成设备的不必要浪费。卸煤机的二次回路相对复杂,依靠继电器进行保护和自动控制,故障率较高。有的操作器件结构复杂,不易维护。而且设计回路也有不合理之处:无法对大车行走电机中的其中一台进行试验;有时会发生火车车厢与绞笼的碰撞,无法在控制回路中对其进行保护,而避免人员操作上的失误。针对这些情况,决定对卸车机进行控制回路改造。新的控制回路采用PLC控制,根据实际生产情况编写了程序,对控制回路进行了重新设计。更换了新型的十字主令控制器,磁感应限位开关。实现了绞笼分阶段下降,减缓了绞笼下降速度,保护了设备,延长了其使用寿命。实现了行走电机的单独控制,增加了防绞笼碰撞保护,确保了卸车机稳定可靠工作。

The 6.7-meter double-screw unloading machine is a large-scale coal unloading device for thermal power plants.The utilization rate is very high and the corresponding faults are also many.Due to the self-weight of the cage,and the irregular operation.When the cage is lowered to the lower limit,although the brake is activated,the cage cannot be stopped immediately,and the mechanical limit of the falling cage is often damaged.The winch often rubs against the bottom plate of the train car when the lower limit is running,causing excessive wear of the winch,resulting in unnecessary waste of equipment.The secondary circuit of the coal unloader is relatively complicated,relying on relays for protection and automatic control,and the failure rate is high.Some operating devices are complicated in structure and difficult to maintain.Moreover,the design loop is also unreasonable:it is impossible to test one of the trolley travel motors;sometimes the collision between the train carriage and the winch can occur,and it cannot be protected in the control loop,and the personnel operation is avoided.Mistakes.In response to these circumstances,it was decided to carry out the control loop transformation of the unloader.The new control loop is controlled by PLC,and the program is programmed according to the actual production situation,and the control loop has been redesigned.Replaced the new cross master controller,magnetic induction limit switch.The stepwise reduction of the stranded cage was achieved,which slowed down the speed of the cage and protected the equipment and prolonged its service life.The individual control of the traveling motor is realized,and the anti-strand cage collision protection is added to ensure the stable and reliable operation of the unloading machine.