除铁器是一种能产生强大磁场吸引力的设备，它的用途是将原料中混杂的铁质和其他磁性物料去除，以保证输送系统中的破碎机、球磨机等机械设备安全正常的工作。
The iron remover is a device that can produce strong magnetic attraction. Its purpose is to remove iron and other magnetic materials mixed with raw materials, so as to ensure the safety and normal work of crusher, ball mill and other mechanical equipment in the conveying system.
我国除铁器的除铁效率普遍不高，有些选厂为了能提高除铁效率，通常都采用2级或3级除铁方法，但仍然不能达到选厂所需要求，其主要原因是处在煤层底部的铁物质受到的电磁力较小，同时还受上层煤的压力作用，所以除铁效果不好。
In addition to our iron iron removal efficiency is generally not high, some plant in order to improve the efficiency of removing iron, usually with 2 or 3 iron removal method, but still cannot reach the plant requirements, the main reason is that in the bottom of the coal seam by the iron material electromagnetic force is small, but also by the pressure the role of the upper coal, so the iron removal effect is not good.
近几年，行业研发了一种提高除铁效率的方法，对电磁铁实施“短时强励”，即在电磁铁极靴的前边、输送带的下边安装一个传感器，其目的是利用传感器检测离极靴最远、吸引效果最弱之处的磁性物质，然后通过传感器将检测到的信号传递给强励整流器，使磁性物质再通过极靴下方时，给磁铁圈短暂的施加高的供电电压，从而产生强大的磁力流，让电磁吸力短时间剧增，这样便能将埋在深处的磁性物质吸出，之后电压便重新恢复到平时的供电状态。
In recent years, the industry developed a method to improve the removal efficiency of iron, the implementation of the "short-term strong excitation of electromagnet, in front of the electromagnet pole, the conveyor belt is arranged under a sensor, its purpose is to use sensors to detect from the pole and the farthest place to attract the weakest effect of magnetic material, and then the detected signal is transferred to the strong excitation rectifier through the sensor, the magnetic material through the pole below when applied to high voltage magnet coil short, resulting in strong magnetic flow, let the electromagnetic suction short time increase, so that they can be buried in the depths of the magnetic material sucking, after the voltage restore to state the usual power supply.
传感器安装在极靴前方的目的，是为了避开电磁铁磁场的干扰，一般情况下，铁物质在煤层上部或中部的时候，不让传感器发送有效信号，只有铁质埋在煤层底部的时候，才可发送有效信号。
The purpose of sensors installed in the front of the pole, to avoid interference of electromagnetic field, under normal circumstances, when the iron material in the middle or upper part of the coal bed, do not let the effective sensor sends a signal, when it is buried in the bottom of the iron coal seam, can send a valid signal.
传感器分为以下几个环节：
The sensor is divided into the following links:
正常励磁触发控制环节
Normal excitation trigger control link
主要是对电磁铁进行正常的励磁控制，需具有触发脉冲移相调节功能，控制主同路的可控硅KP1、KP2，来实现正常励磁电流调节。
It is mainly for normal excitation control of electromagnet. It needs trigger pulse phase shifting function to control the main circuit KP1 and KP2 to achieve normal excitation current regulation.
强励延时控制环节
Strong excitation delay control link
它是提供从检测到有铁物质信号时起，到铁物质正好运行到电磁铁极靴前端这段时间进行延时，然后启动强励控制信号，启动强励触发环节，在最佳时刻进行强励，且尽可能减少强励时间，不错过捕捉良机的目的。
It is supplied from the detected signal of iron, iron material just run to the front electromagnet pole shoe this time delay, and then start the strong excitation control signal, start strong excitation trigger link, strong excitation at the best time, and as far as possible to reduce the strong excitation time, good opportunity to capture.
强励时间控制环节
Strong excitation time control link
主要是控制施加强励时间的长短，将强励时间控制在运行前极靴的前端，到运行后极靴的后端这一段时间，可将强励时间控制在最佳范围内。
The main purpose is to control the length of the strong excitation time, and control the strong excitation time to the front end of the pole shoe before running to the back end of the pole shoe, so that the strong excitation time can be controlled in the best range.
强励触发控制环节
Strong excitation control link
它主要是在强励延时、强励时间的控制下，向强励主回路的可控硅KP3和KP4适时的发出强励触发脉冲，进行强励。另外，不需要对触发脉冲进行移相控制，只需将触发角控制到最小值即可，这样能够获得最大的强励电流。
Under the control of strong excitation delay and strong excitation time, it sends strong excitation pulses to the silicon controlled KP3 and KP4 in the main circuit of the strong excitation, and makes strong excitation. In addition, the phase shift control of the trigger pulse is not necessary, only the trigger angle is controlled to the minimum value, thus the maximum strong excitation current can be obtained.
在目前电磁除铁器的除铁效果不能完全满足除铁需求的情况下，“短时强励”这一方法极大改善了这一状况，十分具有潜力和应用价值。
At present, the iron removal effect of electromagnetic iron remover can't meet the demand of iron removal completely. "Short time strong excitation" method has greatly improved this situation. It has great potential and application value.