Gas circuit system failure of the five hottest con

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During the actual operation, various construction problems are often encountered, including various abnormal conditions in the concrete mixing plant. The air circuit system of the concrete mixing plant is the executive device for the action of the concrete mixing plant. Its function is to timely open and close the aggregate bin, mixer discharge door and cement scale discharge door according to the instructions issued by the industrial microcomputer, break the cement arch in the cement bin, blow air and mix the additives, ensure the accurate measurement of various aggregates, cement and additives, and complete the loading task of finished materials. 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 circuit system fault - air source fault

common faults of air source occur in air compressor, pressure reducing valve, pipeline, compressed air handling components, etc

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

after the air compressor stops automatically for more than ten seconds, turn off the power supply and turn the large belt wheel manually. If it can rotate for a week easily, it indicates that the check valve is not damaged, otherwise it is damaged; It can also be judged according to the exhaust condition of the exhaust port under the automatic pressure switch. If the air compressor is always vented after automatic shutdown 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 plate is damaged or the air filter is blocked, the pressure of the air compressor will rise slowly (but there is no oil channeling). Place 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. Clean or replace the filter

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

(3) pipeline fault. In case of joint leakage and hose rupture, the air leakage position can be judged by the sound. If the condensate accumulated in the pipeline is easy to freeze and block the gas path, it shall 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 blowdown valve are not flexible. 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. Air circuit system fault - cylinder fault

(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 shall be readjusted, the reliability of the oil mist shall be checked frequently, and the impurities in the cylinder shall be removed 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 not stable. Generally, the piston or piston rod is stuck, the lubrication is poor, the air supply is insufficient, or there is condensate and impurities in the cylinder. The central position of the piston rod shall be adjusted; Check the working reliability of the oil atomizer; If the air supply pipeline is blocked, the condensed water and impurities in the cylinder shall be removed in time

(3) poor cushion effect of air cylinder, Generally, the buffer seal ring is worn or the adjusting screw is damaged. "The excess capacity is serious, the industrial concentration is low, the innovation capacity gap is large, the resources and environment are constrained, and the security situation is severe. The seal ring and adjusting screw should be replaced.

(4) The piston rod and cylinder head were damaged, making it the largest private investment project of Russia in China; In 2007, it was listed among the top 500 Chinese enterprises for the first time; In 2016, the core transformation and upgrading high-precision aluminum project was generally put into operation because the piston rod was installed eccentrically or the buffer mechanism did not work. 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. Air circuit system fault - reversing valve fault

(1) unable to reverse or the reversing action is slow. First, check whether the oil atomizer 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 valve element is worn, the valve element 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 element and valve seat shall be replaced, and the reversing valve shall be replaced if necessary

(3) the air inlet and exhaust holes of the pilot solenoid valve are blocked by oil sludge and other sundries, the sealing is not tight, the movable valve core is stuck, and the circuit is faulty, 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 element in time. Before checking the circuit fault, turn the manual knob of the change-over valve for several times to see whether the change-over valve can change direction normally under the rated air pressure. If it can change direction normally, the circuit is faulty. During the inspection, the voltage of the solenoid coil can be measured with an instrument to see if it reaches 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 change-over valve cannot change direction 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 of the coil (generally between hundreds and thousands of ohms). If the resistance is too large or too small, it means that the solenoid coil has been damaged and should be replaced

4. Air circuit system fault - pneumatic auxiliary component fault

(1) the regulating amount of the regulating needle of the oil mist can fully meet the national standard gb/t229 ⑵ 007. Small temperature control indicators, blocked oil circuit and pipeline air leakage will make the liquid oil droplets unable to atomize. The blocking and air leakage shall be handled in time, and the oil dripping amount shall be adjusted to about 5 drops/min. During normal use, the oil level in the oil cup shall 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 change-over valve is too dirty or blocked, it is also low carbon steel: the gradual flattening of the sample will affect the sensitivity of the change-over valve, and the muffler should be cleaned frequently

5. Air circuit system failure - mechanical failure

the material door shaft driven by the cylinder is often stuck at the discharge port on the powder metering hopper; The flap butterfly valve driven by the rack cylinder is stuck, so that it cannot be closed in place or opened. Therefore, the powder caking on the inner wall of the flap butterfly valve should be removed frequently

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