Every city will have a certain number of mixing stations, this is because the construction of high-rise buildings in the city is inseparable from concrete, and the transportation of concrete is inseparable from the automatic feeding mixer, so the automatic feeding mixer is very important. The automatic feeding mixer is composed of many parts, such as the chassis of special vehicle, loading tank, hydraulic system, subframe, reversing valve, etc For example, the valve can not change direction or change direction slowly, gas leakage, electromagnetic pilot valve failure and so on. The following small series will introduce the solutions to these failures.

1.自动上料搅拌车的换向阀不能换向或者换向动作缓慢，一般是因润滑不良、弹簧被卡住或损坏、油污或杂质卡住滑动部分等原因引起的。此时，我们应先检查油雾器的工作是否正常，润滑油的粘度是否合适。必要时，应更换润滑油，清洗换向阀的滑动部分，或更换弹簧和换向阀。

1. The reversing valve of automatic feeding mixer can not change direction or the reversing action is slow, which is generally caused by poor lubrication, spring stuck or damaged, oil or impurities stuck in the sliding part, etc. At this time, we should first check whether the oil atomizer works normally and whether the viscosity of the lubricating oil is appropriate. If necessary, replace the lubricating oil, clean the sliding part of the directional valve, or replace the spring and directional valve.

2.自动上料搅拌车的换向阀经长时间使用后容易出现阀芯密封圈磨损、阀杆和阀座损伤的现象，导致阀内气体泄漏，阀的动作缓慢或不正常换向等故障。此时，需要更换密封圈、阀杆和阀座，或将换向阀换新。

2. After a long time of use, the reversing valve of automatic feeding mixer is prone to wear of valve core sealing ring, damage of valve stem and valve seat, resulting in gas leakage in the valve, slow action or abnormal reversing of the valve. At this time, the sealing ring, valve stem and valve seat need to be replaced, or the change-over valve needs to be renewed.

3.若电磁先导阀的进、排气孔被油泥或其他杂物堵塞，封闭不严，活动铁芯被卡死，电路有故障等，均可导致换向阀不能正常换向，对于前三种情况应清洗先导阀及活动铁芯上的油泥和杂质，而电路故障一般又可分为电路故障和电磁线圈故障两类。

3. If the inlet and exhaust holes of the solenoid pilot valve are blocked by oil sludge or other debris, the sealing is not tight, the movable iron core is stuck, and the circuit is faulty, the reversing valve can not be normally reversed. For the first three cases, the oil sludge and impurities on the pilot valve and movable iron core should be cleaned, and the circuit faults can be divided into circuit faults and solenoid coil faults.

在检查电路故障之前，要先将换向阀的手动旋钮转动几下，看换向阀在额定的气压下是否正常换向，若能正常换向，则是电路有故障；检查时，可以用仪表测量电磁线圈的电压，看是否达到了额定电压，如果电压过低，应进一步检查控制电路中的电源和相关联的行程开关电路。

Before checking the circuit fault, turn the manual knob of the directional valve a few times to see whether the directional valve can change direction normally under the rated air pressure. If it can change direction normally, the circuit is faulty. When checking, use the instrument to measure the voltage of the solenoid coil to see whether it reaches the rated voltage. If the voltage is too low, further check the power supply and related lines in the control circuit The circuit of the range switch.

如果在额定电压下换向阀不能正常换向，则应检查电磁圈的接头是否松动或接触不实，检查方法：拔下插头，测量线圈的阻值（一般应在几百欧姆几千欧姆之间），如果阻值太大或太小，说明电磁线圈已损坏，需要更换。

If the reversing valve can not change direction normally under the rated voltage, check whether the connector of the solenoid coil is loose or not. Check method: pull off the plug and measure the resistance of the coil (generally between several hundred ohm and several thousand Ohm). If the resistance is too large or too small, it means that the solenoid coil is damaged and needs to be replaced.