Analysis and solution of common failures of pulse dust collector
Grain dust is the main fuel source of explosion during grain loading, unloading and transportation. Grain dust is highly combustible. If sufficient grain dust disperses in the air or accumulates on the surface of an object and encounters ignition source (such as hot bearings, overheated motors, off-track conveying belts, welding, cutting, etc.), it will burn or explode.
The U.S. Occupational Safety and Health Administration (OSHA) standards require that grain processing and storage companies must control grain dust and ignition sources to prevent the fatal explosion. For grain and oil processing enterprises, dust collector is the key equipment to control dust effectively. Maintaining dust removal equipment in good working condition reduces the risk of explosion and helps to provide better safety for the staff on duty.
一、除尘器工作原理Working principle of dust collector
Dusty gas enters the middle box tangentially from the air inlet, through rotation separation. The larger dust particles settle firstly,the dusty gas is filtered by filter bags to become purified air, enters the upper box, and discharges from the air outlet,dust accumulates on the outer surface of filter bags. When the accumulated dust reaches a certain amount, it must be cleaned. When cleaning dust, the high-pressure airflow injects air according to set requirements while each solenoid valve is triggered by pulse controller and enters filter bags through nozzle holes. The filter bags expand instantly and rapidly to shake off the dust accumulating on the surface of filter bags and then enters dust discharge device,and discharges through the airlock, and the dust is cleaned by periodic pulse blowing so that filter bags are in effective filtration state and the dust removal system works normally.
Dust removal process: the power of dust removal is compressed air → through the action of the controller and solenoid valves → open the pulse valve → the compressed air is released instantly → and eject air which is several times as the amount of compressed air → inject the filter bags together through venturi→ the dust on the surface of filter bags falls off.
二、常见故障的原因及处理方法Causes and solution of common failures
Solving the failures of dust collector timely and effectively not only can ensure the continuity of production, but also have positive meaning for extending the service life of dust collector.
The suction volume of dust collector is reduced, and the exhaust inlet can not collect dust effectively
Cause 1: The air duct is blocked and the air door is shifted.
Solution: Clean the air duct and fix the air door.
Cause 2: The dust collector and air duct are not tightly sealed, there is air leakage locally.
Solution: Check and solve the sealing of dust collector and air duct.
Cause 3: The designed air volume of dust collector is too small.
Solution: Replace the dust collector.
Cause 4: The fan does not match.
Solution: Replace the fan.
Cause 5: The filter bag is blocked.
(1) When the dusty gas concentration is too large, increase pre-filter or enlarge dust collector.
(2) When the humidity of dusty gas is too high, preserve heat or heat, and replace it with water-repellent membrane filter materials.
(3) When the dusty gas has strong hygroscopicity and adheres to the surface of filter bags,preserve heat or heat and replace it with membrane filter materials.
(4) When filter bags works long time, replace the filter bags.
(5) When set cleaning cycle is too long and the blowing width is too short, adjust the pulse controller to shorten the cleaning cycle.
(6) When filter bags are affected by the oil or water in the sprayed gas, clean the filter.
(7) When the cleaning intensity is insufficient, adjust the blowing pressure.
(8) When the pulse controller is in disorder and cannot control the dust removal, check the controller.
(9) When the solenoid valve does not work, the coil is damaged, the diaphragm is damaged and deformed, or the spring fails, replace it in time.
(10) When the solenoid valve does not work and the setting loop is incorrect, adjust the pulse controller to reset it.
(11) When the shutdown sequence is wrong and the injection is not extended, adjust the shutdown sequence according to the specifications and increase the injection delay.
(12) When the dust discharge is not smooth and accumulated dust is too much, clean the dust hopper and check the dust discharge device.
The air suction volume of dust collector is too large, and the exhaust inlet sucks too much dust
Cause 1: The air door is shifted.
Solution: adjust and fix the air door.
Cause 2: The designed air volume of dust collector is too large.
Solution: replace the dust collector.
Cause 3: The fan does not match.
Solution: Replace the fan.
Cause 4: The filter bag is damaged or falling off.
Solution: Check the filter bag.
Cause 5: The amount of accumulated dust in the filter bag is too small.
(1) When the cleaning cycle is too short and the blowing pulse is too wide, adjust the pulse controller to extend the cleaning cycle.
(2) When the cleaning intensity is too high, adjust the blowing pressure.
There is dust at the outlet of dust collector
Cause 1: The filter bag is damaged and falling off.
Solution: Check the filter bag.
Cause 2: The filter bag is not properly installed and sealed.
Solution: Check and re-install.
Cause 3: The flower board is damaged.
Solution: Repair the flower board.
Cause 4: The size of dust particle is too small.
Solution: Replace the filter materials.
Cause 5: The cleaning cycle is too short and the blowing pulse is too wide.
Solution: Adjust the pulse controller to extend the cleaning cycle.
Cause 6: The cleaning intensity is too strong.
Solution: Adjust the blowing pressure.
Dust accumulation in dust hopper of dust collector
Cause 1: The dust is not discharged timely.
Solution: Adjust the frequency of dust discharge.
Cause 2: The ash discharge device is abnormal.
Solution: Repair the dust discharge device.
Cause 3: Air leakage at the dust discharge port.
Solution: check the seal
Cause 4: Dust accumulation.
Solution: Increase the dust discharge angle, clean up manually or use strike vibrator
Cause 5: The humidity of dust is high.
Solution: Take measures to preserve heat
The research from the first global dust fire and explosion tracking platform DustEx in the world shows that since 2016, dust collection equipment has accounted for the largest proportion in combustible dust accidents, with an average of 23%. The historical data of the U.S. Chemical Safety and Hazard Investigation Board (CSB) shows that the proportion of dust removal equipment in dust accidents reaches 40%.
Compared with other equipment, dust collectors account for smaller proportion in recorded dust explosion accidents, but there were many injured people. Ensuring dust collector in good working condition is crucially important to the proper operation in grain and oil plants or warehouses.