In the actual operation process, often encounter a variety of construction problems, including concrete mixing station will also appear various abnormal conditions. The air-way system of concrete mixing station is the executing device of concrete mixing station. Its function is to switch on and off aggregate silos, unloading doors of mixers and cement weighing unloading doors in time according to the instructions issued by industrial computers, break the arch of cement in the cement silo, blow and mix additives to ensure the accurate measurement of various aggregates, cement and additives, and complete the loading task of finished materials. Only by using and maintaining the system correctly can the efficiency and economy of the whole machine be guaranteed.
The common faults are as follows:
1. Breakdown of Gas Circuit System - Breakdown of Gas Source
Common faults of air source occur in air compressor, pressure reducing valve, pipeline, compressed air handling unit, etc. (1) The common faults of air compressor are check valve damage, serious wear of piston ring, damage of intake valve piece and blockage of air filter.
After ten seconds of automatic shutdown of air compressor, turn off the power supply and move the large belt wheel by hand. If it can rotate for a week easily, it shows that the check valve is not damaged, otherwise it has been damaged. It can also be judged according to the exhaust situation of the exhaust outlet under the automatic pressure switch. If the air compressor exhausts continuously after automatic shutdown and stops until the air compressor starts again, the check valve itself will be explained. Damage, need to be replaced. When the pressure of air compressor rises slowly and accompanied by oil channeling, it shows that the piston ring of air compressor has been seriously worn and should be replaced in time. When the intake valve piece is damaged or the air filter is blocked, the pressure of the air compressor will rise slowly (but there is no oil channeling). Place the palm on the air filter inlet, if there is hot air outside the top, it means that the intake valve has been damaged and needs to be replaced; if the suction is small, it is usually caused by dirty air filter, the filter should be cleaned or replaced.
(2) Fault of pressure relief valve. Pressure adjustment is not high, often the spring or diaphragm break, must be updated; pressure rise slowly, usually blocked filter, should be removed and cleaned.
(3) Pipeline failure. When the joint leaks and the hose ruptures, the location of the leak can be judged by sound. If condensate accumulates in the pipeline, it is easy to freeze and block the air passage, it should be removed in time.
(4) Compressed air treatment component failure. The filter element of oil-water separator is blocked and damaged, and the moving parts of the sewage valve are not flexible. The filter element should be cleaned regularly to remove impurities such as oil contamination in the drain valve. Oil atomizer does not drip oil, water is deposited at the bottom of oil cup, sealing ring of oil cup mouth is damaged, etc. Should check whether the air flow in the intake is lower than the fogging flow, whether it leaks, whether the oil flow control needle valve is blocked, etc.
2. Breakdown of Gas Circuit System - Cylinder Breakdown
(1) Internal and external leakage of cylinder is generally caused by eccentric installation of piston rod, insufficient supply of lubricating oil, wear or damage of sealing ring and sealing ring, impurities in cylinder and scars on piston rod. The central position of the piston rod should be readjusted, the reliability of the oil mist should be checked frequently, and the impurities in the cylinder should be removed in time. When there is a scar on the piston rod, new parts should be replaced.
(2) The output force of the cylinder is insufficient and the operation is not stable. Generally, the piston or piston rod is stuck, lubricated badly, the air supply is insufficient, or there are condensate and impurities in the cylinder. The central position of the piston rod should be adjusted; the reliability of the oil mist should be checked; whether the gas supply pipeline is blocked or not, the condensate and impurities in the cylinder should be removed in time.
(3) The cushioning effect of cylinder is not good, usually because of the wear of cushioning ring or the damage of adjusting screw, the sealing ring and adjusting screw should be replaced.
(4) The damage of piston rod and cylinder head is generally due to the eccentric installation of piston rod or the inactive cushioning mechanism. The central position of piston rod should be adjusted in time, and the cushioning sealing ring or adjusting screw should be replaced if necessary.
3. Breakdown of Gas Circuit System-Breakdown of Commutation Valve
(1) Can't change direction or change direction slowly. It is necessary to check whether the oil mist is working properly and whether the lube oil is suitable. If necessary, replace the lubricant, clean the sliding part of the reversing valve or replace the spring and the reversing valve.
(2) The spool seal ring is worn out, the spool and seat are damaged, the gas inside the valve leaks, and the action is slow or can not be reversed normally. The sealing ring, spool and seat should be replaced, and the new reversing valve should be replaced if necessary.
(3) Inlet and exhaust holes of the first conductive solenoid valve are blocked by impurities such as sludge, improper sealing, blocked active spool and circuit failure, which can lead to the reversing valve can not be reversed normally. The impurities such as sludge on the leading solenoid valve and movable spool should be cleaned in time. Before checking the circuit failure, the manual knob of the reversing valve should be rotated several times to see if the reversing valve can be reversed normally under rated air pressure. If the reversing valve can be reversed normally, the circuit will be faulty. When checking, 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 related trip switch circuit should be further checked. If the commutation valve can not commute normally under rated voltage, check whether the connection (plug) of the solenoid coil is loose or not. The method is to unplug the plug and measure the resistance of the coil (usually between hundreds and thousands of ohms). If the resistance is too large or too small, it means that the electromagnetic coil has been damaged, it should be replaced.
4. Breakdown of Gas System-Breakdown of Pneumatic Auxiliary Components
(1) The adjustment amount of the adjusting needle of the oil mist is too small, the blockage of the oil pipeline and the leakage of the pipeline will make the liquid oil droplets unable to atomize. The blockage and leakage should be handled in time, and the amount of oil droplets should be adjusted so as to reach about 5 drops/min. Oil in oil cup during normal use