The failure of the reversing valve of the cutting machine includes: the valve cannot be reversed or the reversing action is slow, the gas leaks, and the electromagnetic pilot valve is faulty.
(1) The reversing valve cannot be reversed or the reversing action is slow, generally caused by poor lubrication, spring jamming or damage, oil stains or impurities jamming the sliding part. In this regard, first check whether the oil mister is working properly; whether the viscosity of the lubricating oil is appropriate. If necessary, replace the oil, clean the sliding part of the reversing valve, or replace the spring and the reversing valve.
(2) After the valve is used for a long time, the valve reversing valve is prone to wear of the valve core seal, damage to the valve stem and the valve seat, resulting in gas leakage in the valve, slow valve operation or failure to normal commutation. In this case, replace the seal, stem and seat, or replace the reversing valve.
(3) If the inlet and exhaust holes of the electromagnetic pilot valve are blocked by oil and other debris, the sealing is not strict, the movable iron core is stuck, the circuit is faulty, etc., and the reversing valve can not be normally reversed. For the first three cases, the sludge and impurities on the pilot valve and the moving iron core should be cleaned. Circuit faults are generally divided into two types: control circuit faults and electromagnetic coil faults. Before checking the circuit fault, first turn the manual knob of the reversing valve a few times to see if the reversing valve can be normally reversed under the rated air pressure. If the commutation is normal, the circuit is faulty. During the inspection, the voltage of the electromagnetic coil can be measured by the meter to see if the rated voltage is reached. If the voltage is too low, the power supply in the control circuit and the associated stroke switch circuit should be further checked. If the reversing valve cannot be reversed normally at the rated voltage, check the connector (plug) of the solenoid for looseness or contact. The method is to unplug the plug and measure the resistance of the coil. If the resistance is too large or too small, the solenoid is damaged and should be replaced.