Concrete mixing station valve failure are: the valve can not change or change the direction of action, gas leakage, electromagnetic pilot valve failure.
(1) concrete mixing station reversing valve can not be reversed or reversing action is slow, generally due to poor lubrication, the spring was stuck or damaged, oil or impurities caught in sliding part of the cause. In this regard, should first check the work of the oil mist is normal; lubricating oil viscosity is appropriate. If necessary, replace the lubricating oil, clean the sliding part of the reversing valve, or replace the spring and the reversing valve.
(2) concrete mixing station valve after a long period of time prone to use the valve ring seal wear, stem and valve seat damage phenomenon, resulting in valve gas leakage, the valve action is slow or can not be normal commutation and other failures. At this point, should replace the seals, stem and valve seat, or change the valve.
(3) If the electromagnetic pilot valve into the exhaust hole is blocked by mud and other debris, closed lax, the activities of the core was stuck, the circuit is faulty, can lead to the valve can not be normal for the direction. In the first three cases, the oil and impurities on the pilot valve and the movable iron core should be cleaned. The circuit failure is generally divided into control circuit failure and electromagnetic coil failure two categories. Before checking the circuit failure, you should first turn the valve manually turn a few times to see the valve under the rated pressure can be normal for the direction, if the normal commutation, it is a circuit failure. During the inspection, the voltage of the solenoid can be measured by the instrument to see if the rated voltage has been reached. If the voltage is too low, the power supply in the control circuit and the associated trip switch circuit should be further checked. If the reversing valve can not be changed normally at rated voltage, check whether the connector (plug) of the solenoid is loose or not in contact. Method is to unplug the plug, measuring the coil resistance (usually in the hundreds of ohms to several thousand ohms), if the resistance is too large or too small, indicating that the solenoid is damaged, should be replaced.
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