Reviewing the old to gain new insights: Common faults of bag dust collectors and their solutions

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Common faults of bag dust collectors and their troubleshooting methods: Check the air ducts for corrosion, leaks, or any external damage. Check for loose bolts, welding cracks, and dust accumulation in any areas (mainly on straight pipes and reducers). Check whether the solenoid/pulse valve is operating correctly: listen for the sound of compressed air being ejected. Is the pressure relief valve leaking? Be careful as there may be debris inside the pressure relief valve. Ensure that the fan is installed firmly and horizontally, and refuel it regularly. Be aware that dust tends to accumulate on the blades. Check the compressed air system to ensure that the compressor is properly lubricated. Check for cracks on the air tanks and pipes ； Pay attention to the pressure indication of the pressure regulator (if installed). Check whether the air compressor and air tank are draining water. All access doors must be securely sealed. Check whether the seal strip is loose, cracked, or worn. Replace as needed. Check the inlet/outlet guide plates for excessive wear or corrosion. Check the air volume control valve and lift valve, as well as the oiler (if necessary), to ensure they are operating properly. Common faults and troubleshooting methods for bag dust collectors: Symptoms, possible causes, and solutions. High differential pressure: Incorrect reading of the differential pressure; clean the pressure measurement interface/ check for cracks in the air pipes/ inspect the differential pressure gauge. Incorrect settings of the cleaning system: Increase the cleaning frequency/ insufficient pressure of compressed air ； Increase pressure/ Check the dryer and clean it if necessary/ Check for blockages in the pipelines. If the spray valve is not working, check the diaphragm valve/ Check the control solenoid valves. If the pulse controller is not functioning, check whether the controller indicates all the contacts/ Check the output of each terminal. Clogged filter bags, condensation on the filter bags (see below) ； Send the filter bag to the laboratory for analysis of the cause. Drying and cleaning of filter bags / or replacement of them / reducing air flow rate / increasing compressed air pressure / increasing the frequency of cleaning / spraying neutral modifying powder to form a protective layer as well as a porous, loose primary cake. Excess secondary dust should be continuously removed from the ash hoppers / and each row of filter bags/tubes should be cleaned in a random sequence, rather than in order. Check the inlet baffle to ensure it is clean. Low fan motor current/low air volume, high dust collector pressure difference; see above. The pulleys of the fan and motor are connected in the wrong order; check the drawings and reverse the connection of the pulleys. Clean the pipes clogged by dust accumulation, and check the gas flow rate. Close the fan baffle; open the baffle and lock it in the open position. Check the air circuit with the dust collector lift valve closed; open the valve plate. If the system’s static pressure is too high, measure the static pressure at both ends of the fan and check the design specifications, making adjustments as necessary. Replace the original poor design of the pipeline for high-flow rate inspections. The fan is not operating within the specified design parameters; check the fan’s inlet structure to ensure smooth airflow. Check the blades for wear; repair or replace them as needed. Reverse the rotation of the fan by reversing the wiring on the motor. The volume of air from which dust escapes at the dust collection point is small; see above. Repairing cracks in the pipeline prevents dust from bypassing the dust collection point. If the pipeline balance is incorrect, adjust the dampers on the branch pipelines. The suction hood is poorly designed, leaving the area surrounding the dust collection point open. Check whether the flat-suction ventilation device can overcome the suction force. Check whether dust is carried out of the suction hood by the belt. Replacement of ash leakage filters in chimneys: If the filter bag is torn or has small holes. Check the installation of the spring coils to ensure they are tight. Ceiling leakage at joints or welds. There is no sufficient dust cake to reduce the compressed air pressure ； Reduce dust cleaning frequency / Inject neutral modulating powder to form a primary dust cake. Perform a permeability test on filters or cartridge filters with too many pores, and consult the manufacturer. The fan is severely worn; for handling excessive dust in the fan, see above. The fan is not properly evaluated to determine whether it is suitable for the operating conditions ； Consult the manufacturing factory. If the fan speed is too high, consult the manufacturer. The fan is vibrating severely due to dust accumulation on the blades; clean the blades and check whether the fan has been exposed to excessive dust. Check the fan’s installation location/ Drain condensation or moisture/ Keep the fan dry. Consult the manufacturer if the fan impeller is not suitable for the operating conditions. The pulley is not level; a cross pulley is used for dynamic balancing. Bearing wear requires replacement. Excessive use of compressed air leads to a shorter dust cleaning cycle; if possible, reduce the blowing time – all air flow beyond the initial impact is wasted ； Usually, the injection time is set to 0.1 seconds.) If the pressure is too high, check the diaphragm and spring (see the analysis of valve failure earlier in this chapter). For air tube leaks, conduct a bubble test and repair them. If the compressed air pressure is low or the consumption of compressed air is too high, refer to the points mentioned above. Check for blockages in the air tube to ensure there are no obstructions. If the dryer is clogged, replace the desiccant or bypass it if the operating conditions permit. For issues related to compressor wear, consult the manufacturer or refer to the compressor maintenance manual. If the air flow is too high, seal any leaks in the pipes; if the static pressure is insufficient, close the air valves. Reduce the fan speed; low air compression demand. The pulse valve is not working – check the pulse valve using the methods mentioned earlier. If the controller is malfunctioning, check the terminal outputs using the same methods. Premature failure of the filter bags – the filter media used is not suitable for this operating condition; analyze the chemical properties of the gas and consult the manufacturer of the filter bags or cartridges. The filter media is not appropriate for the gas composition; preprocess the gas before it enters the dust collector ； Either replace the filter bag or filter cartridge, or increase the gas temperature at the acid dew point temperature. High efficiency loss of the filter bags during startup due to bypassing – excessive wear of the flow equalizing baffles; these baffles need to be replaced. Excessive dust present: a primary dust collector should be installed. The dust cleaning cycle is too frequent; the cycle time needs to be extended. The inlet airflow is not properly evenly distributed by the filter bags or cartridges; consult the manufacturer. Dust is present in the clean air chamber/ceiling panels; clean the ceiling panels as well as the inside of the filter bags or cartridges ； Conduct a fluorescence test to locate the leak point; remove burrs/corrosion on the frame (if used) and smooth out any burrs ； Replace if necessary. If corrosion is a concern, consider using a cage frame with an anti-corrosion coating. High filter bag failure rate – baffles are used in the pipes with a layered distribution of hot and cold combustion gases to eliminate turbulence. A spark arrester is installed inside the dust collector to capture sparks. Replace the failed thermocouple and determine the cause of the failure. For a failed cooling unit, check the design specifications and consult the manufacturer. Since the moisture in the dust collector is not heated sufficiently, hot air is introduced into the system before starting to process the airflow. There is no purging system after shutdown; the fan runs for 15~20 minutes after the system stops. Lowering the casing temperature below the dew point temperature raises the gas temperature; unit insulation helps to retain heat; reducing moisture within the system also helps to lower the dew point temperature. External air is introduced into the dust collector to check for leaks in the housing and wear on the door seals. A colder object is placed inside the insulation layer to avoid using metal as the inner lining. Check for moisture in the compressed air; install an automatic drain or a secondary cooler/dryer. If the process conditions deteriorate, inject modified powder. The hinge conveyor system is severely worn or has insufficient capacity; measure the dust collection rate per hour and consult the manufacturer. If the conveyor speed is too high, reduce it. The star-shaped discharge valve is severely worn or the size of the discharger is too small; measure the dust collection rate per hour and consult the manufacturer. For issues related to thermal expansion, consult the manufacturer. If the rotation speed is too high, reduce it. Material buildup in the hopper and moisture inside the dust collector – see points above. The design of the hopper hinders the movement of material; install acoustic horns or vibrators to facilitate material movement. Dust accumulates in the ash hopper for continuous ash discharge ； Do not store ash in the ash hopper; the conveyor opening is too small – use wide, flared trough-shaped blades ； The feeder/star discharge valve is not functioning or is of insufficient size. The conveyor/star discharge valve fails frequently; the cage conveyor is not aligned – realign the conveyor. The components are overloaded; check the sizes to ensure that each component has the capacity to handle 100% of the material conveyed from the front. The equipment is too small – consult the manufacturer. The pneumatic conveyor is severely worn; the pneumatic blower operates at too high a speed – reduce the speed of the blower. The air ducts are too small – check the design specifications and either resize the blowers or increase the diameter of the air ducts. The bend radius is too short – replace it with a bend of a larger radius. The air ducts of the pneumatic conveyor are blocked; the pneumatic conveyor is overloaded – check the design specifications ； Acoustic speakers are installed on the air duct to gradually control the discharge of dust; if the dust is moist, refer to the above instructions. If the fan motor is overloaded due to excessive airflow, check the opening degree of the fan inlet. See above. If the motor size is not suitable, adjust the fan damper when starting in cold conditions, reduce the fan speed, or replace the motor. If the outlet butterfly valve does not work – it may be stuck; insufficient lubricating oil should be added – check the lubricator and fill it as needed. If the adjustment is incorrect or the lubricator is malfunctioning, carry out adjustments, repairs, or replacements. Water is present in the air circuit – identify the cause ； Replace the water separator. The outlet butterfly valve is not functioning due to low air pressure. Check the air compressor to confirm it is working properly; repair any cracks in the air supply lines; reduce other air consumption. If the solenoid valve is not working, check its power supply ； If damaged, replace it; if the slide valve is stuck, remove it to determine the cause ； If damaged, replace it