Common fault causes and troubleshooting of pneumat

Causes and troubleshooting of common faults in the pneumatic system of concrete mixing station

causes and troubleshooting of common faults in the pneumatic system of concrete mixing station:

the pneumatic system is the executive device of the action of concrete mixing station. Its function is to timely open and close all bone silos, mixer discharge doors, and cement scale discharge doors according to the instructions issued by the industrial microcomputer, break the arch of cement in the cement silo, blow air and mix additives, and ensure that all kinds of aggregates, cement Accurately measure the additives and complete the loading task of finished products. Only the correct use and maintenance of the system can ensure the high efficiency and good economy of the whole machine production

there are five common faults:

1 Air source failure

common failures of air sources occur in air compressors, pressure reducing valves, pipelines, compressed air handling components, etc

(1) the common faults of the air compressor are the damage of the check valve, the serious wear of the piston ring, the damage of the inlet valve plate and the blockage of the air filter

after the air compressor stops automatically for more than ten seconds, turn off the power supply and turn the large belt wheel by hand. If it can rotate for a week easily, it indicates that the check valve is not damaged, otherwise it has been damaged; It can also be judged according to the exhaust condition of the exhaust port under the automatic pressure switch. If the air compressor always exhausts after automatic shutdown and does not stop until the air compressor is started again, it indicates that the check valve has been damaged and needs to be replaced. When the pressure of the air compressor rises slowly with oil channeling, it indicates that the piston ring of the air compressor has been seriously worn and should be replaced in time. When the inlet valve is damaged or the air filter is blocked, the pressure of the air compressor will rise slowly (but there is no oil channeling). Put your palm on the air inlet of the air filter. If there is hot air pushing outward, it means that the air inlet valve is damaged and needs to be replaced; If the suction is small, it is generally caused by the dirty air filter. The filter should be cleaned or replaced

(2) pressure reducing valve failure. If the pressure is not adjusted high, the pressure regulating spring is often broken or the diaphragm is broken, and it must be renewed; The pressure rises slowly, which is generally due to filter blockage. It should be removed for cleaning

(3) pipeline failure. In case of joint leakage and hose rupture, the position of air leakage can be judged by sound. If condensate accumulates in the pipeline, it is easy to freeze and block the gas path, it should be eliminated in time

(4) compressed air handling component failure. The filter element of the oil-water separator is blocked or damaged, and the moving parts of the drain valve are not flexible, etc. Clean the filter element frequently to remove oil and other impurities in the blowdown valve. The oil atomizer does not drip oil, moisture is deposited at the bottom of the oil cup, and the sealing ring at the mouth of the oil cup is damaged. Check whether the air flow at the air inlet is lower than the fog flow, whether there is air leakage, whether the oil volume regulating needle valve is blocked, etc

2. Cylinder failure

(1) internal and external leakage of the cylinder is generally caused by eccentric installation of the piston rod, insufficient supply of lubricating oil, wear or damage of the sealing ring and sealing ring, impurities in the cylinder and scars on the piston rod. The central position of the piston rod should be readjusted, and the reliability of the oil atomizer should be checked frequently to remove impurities in the cylinder in time; If there is a scar on the piston rod, replace it with a new one

(2) the output force of the cylinder is insufficient and the action is unstable. Generally, it is because the piston or piston rod is stuck, the lubrication is poor, the air supply is not enough for the steel strand test (please note when ordering), or there is condensate and impurities in the cylinder. Adjust the central position of the piston rod; Check the reliability of the oil atomizer; If the air supply pipeline is blocked, the condensed water and impurities in the cylinder should be removed in time

(3) the buffer effect of the cylinder is poor, which is generally due to the wear of the buffer seal ring or the damage of the adjusting screw. The seal ring and adjusting screw should be replaced

(4) the damage of the piston rod and cylinder head is generally due to the eccentric installation of the piston rod or the failure of the buffer mechanism. The central position of the piston rod should be adjusted in time, and the buffer seal ring or adjusting screw should be replaced if necessary

3. Reversing valve fault

(1) unable to reverse or the reversing action is slow. Oil mist should be checked first. 6. Why should we strengthen the construction of new material collaborative innovation system? Whether the device works normally; Whether the clearance 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) if the sealing ring of the valve core is worn, the valve core and valve seat are damaged, the gas in the valve leaks, the action is slow or the normal reversing is not possible, the sealing ring, valve core and valve seat should be replaced, and the reversing valve should be replaced if necessary

(3) the inlet and outlet holes of the pilot solenoid valve are blocked by debris such as oil sludge, the sealing is not tight, the movable valve core is stuck, and the circuit fails, which can lead to the normal reversing of the change-over valve. Clean the oil sludge and other impurities on the pilot solenoid valve and movable valve core in time. Before checking the circuit fault, turn the manual knob of the reversing valve for several times to see whether the reversing valve can reverse normally under the rated air pressure. If it can reverse normally, the circuit is faulty. During the inspection, the voltage of the solenoid coil can be measured with an instrument to see whether it has reached the rated voltage. If the voltage is too low, further check the power supply in the control circuit and the related travel switch circuit. If the reversing valve cannot reverse normally under the rated voltage, check whether the connector (plug) of the solenoid coil is loose or not. The method is to unplug the plug and measure the resistance value of the coil (generally between hundreds and thousands of ohms). If the resistance value is too large or too small, it means that the solenoid coil has been damaged and should be replaced

4. Pneumatic auxiliary component failure

(1) the adjustment amount of the adjusting needle of the oil mist is too small, the oil circuit is blocked, and the pipeline leaks air, which will make the liquid oil droplets unable to atomize. The blockage and air leakage should be handled in time, and the oil dripping 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

(2) sometimes the oil and water in the automatic blowdown cannot be removed automatically, so it should be removed for inspection and cleaning

(3) when the muffler installed on the reversing valve is too dirty or blocked, it will also affect the sensitivity of the reversing valve. It is necessary to clean the muffler often

5. Mechanical failure

the discharge port on the powder metering hopper often has a material door driven by the cylinder. Annual operation of the electronic tensile testing machine. Don't worry. Nearly 2000 shafts are stuck; The flap butterfly valve driven by the rack cylinder is stuck, making it unable to close in place or open. Therefore, the powder caking on the inner wall of the flap butterfly valve should be removed frequently