Common Failures of Concrete Mixing Station-Reversing Valve Failure & Component Failure

1. Reversing valve failure

The faults of the reversing valve include: the valve can not be reversed or the reversing action is slow, the gas leaks, and the electromagnetic pilot valve is faulty.

(1) The reversing valve can't reverse or the reversing action is slow, which is generally caused by poor lubrication, the spring being stuck or damaged, oil pollution or impurities stuck in the sliding part, etc. In this regard, we should first check whether the oil mist device works normally; Whether the viscosity of lubricating oil is appropriate. If necessary, replace the lubricating oil, clean the sliding part of the reversing valve, or replace the spring and reversing valve.

(2) After long-term use, the reversing valve is prone to wear of the sealing ring of the valve core and damage of the valve stem and valve seat, resulting in gas leakage in the valve, slow action of the valve or abnormal reversing. At this time, the sealing ring, valve stem and valve seat should be replaced, or the reversing valve should be replaced.

(3) If the inlet and exhaust holes of the electromagnetic pilot valve are blocked by impurities such as sludge, the sealing is not strict, the movable iron core is stuck, and the circuit is faulty, etc., the reversing valve can not be reversed normally. In the first three cases, the sludge and impurities on the pilot valve and the movable iron core should be cleaned. Circuit faults are generally divided into control circuit faults and electromagnetic coil faults. Before checking the circuit fault, turn the manual knob of the reversing valve a few times to see if the reversing valve can reverse normally under the rated air pressure. If it can reverse normally, it is a circuit fault. During the inspection, the voltage of the electromagnetic coil can be measured with an instrument to see if it reaches the rated voltage. If the voltage is too low, the power supply in the control circuit and the associated travel switch circuit should be further inspected. If the reversing valve can't reverse normally under rated voltage, check whether the connector (plug) of the electromagnetic coil is loose or not. The method is to unplug the plug and measure the resistance of the coil (generally between several hundred ohms and several thousand ohms). If the resistance is too large or too small, the electromagnetic coil is damaged and should be replaced.

2. Component failure

The faults of pneumatic conveying components mainly include: oil mist fault, automatic blowdown fault, muffler fault and so on.

Faults of the oil fogger include: the adjustment amount of the adjusting needle is too small, the oil circuit is blocked, and the pipeline leaks, which will make the liquid oil droplets unable to be atomized. In this regard, the blockage and air leakage should be dealt with in time, and the oil drop amount should be adjusted to reach about 5 drops /min. During normal use, the oil level in the oil cup should be kept within the upper and lower limits. The water deposited at the bottom of the oil cup should be removed in time.