What Causes Excessive Vibration of Fans in Waste Gas Treatment Equipment?

When operating VOCs waste gas treatment systems, dust removal equipment, desulfurization and denitrification devices, fan vibration is one of the most frequent faults that maintenance teams encounter. Persistent excessive vibration will shorten the service life of bearings, loosen connecting bolts, crack the fan shell and duct, and even lead to unexpected shutdown of the whole waste gas treatment line. It will also affect the stable emission index of the environmental protection system.

Zhengzhou Puhua Technology is a professional manufacturer of environmental protection equipment in Henan Province. The company focuses on the design, research, development and production of dust control equipment, desulfurization equipment, denitrification equipment, VOCs waste gas treatment equipment, pneumatic conveying equipment and sewage treatment equipment. Its product portfolio includes baghouse dust collectors, RCO catalytic combustion equipment, RTO equipment, VOCs treatment systems, desulfurization towers, denitrification units, photo-oxygen catalytic equipment, pulse dust collectors, mobile dust collectors, ultra-low emission equipment and sewage treatment equipment. In long-term after-sales and technical service practice, the technical team of Zhengzhou Puhua Technology has summed up a complete set of diagnosis and maintenance methods for fan vibration faults of waste gas treatment equipment.

1. Impeller Unbalance: The Most Common Reason for Fan Vibration

Impeller unbalance accounts for the largest proportion of fan vibration faults in waste gas treatment projects. The rotating impeller loses uniform mass distribution, and continuous centrifugal force will be generated during operation, bringing obvious vibration to the whole blower.

• Uneven adhesion of dust, tar or sticky pollutants on fan blades. This situation often occurs in the front-end fan of baghouse dust collectors and RCO catalytic combustion devices;

• Blade corrosion, abrasion or local damage caused by corrosive waste gas and particulate matter;

• Dynamic balance failure after on-site maintenance, blade replacement or impeller cleaning.

The conventional solution is to stop the machine for impeller cleaning, check the blade integrity, and carry out on-site dynamic balancing calibration when necessary. Regular inspection and cleaning are effective preventive measures for fans in waste gas treatment equipment.

2. Shaft and Coupling Misalignment

The fan shaft and motor shaft need to maintain accurate coaxiality. If the alignment deviates beyond the allowable range, periodic vibration will appear during rotation. This fault may appear after the first commissioning, or gradually emerge after long-time operation due to foundation settlement, thermal expansion and bolt loosening.

Common inspection points include radial offset and angular offset of the coupling. After re-alignment, the locking bolts should be tightened according to the specified torque.

3. Bearing Damage and Lubrication Abnormity

Bearings are the core supporting parts of the fan rotating assembly. Wear, pitting, clearance exceeding the standard, insufficient lubricating oil or deteriorated lubricant will all trigger abnormal vibration and abnormal noise.

4. Mechanical Looseness of Installation Base and Fasteners

The stable foundation and shock absorption components are the key to control fan vibration. Loose anchor bolts, aging shock absorbers, uneven foundation and cracks on the base will reduce the rigidity of the supporting structure and amplify vibration.

For the fans matched with RTO, desulfurization tower and pulse dust collector, it is suggested to check the fastening state of all connecting bolts regularly. If the shock absorption pad is aged and hardened, replace it in time to avoid rigid contact between the fan and the foundation.

5. Pipeline Stress and Aerodynamic Resonance

Many vibration problems are not caused by the fan itself, but transmitted from the waste gas pipeline system.

• The duct applies extra pulling force on the fan flange due to improper installation, and the pipeline stress deforms the fan casing;

• The airflow forms turbulence, eddy current or air separation at the fan inlet and outlet;

• The natural frequency of the fan and pipeline structure is close to the working frequency, and structural resonance occurs.

When this kind of fault occurs, it is necessary to check whether the soft connection between the fan and the pipeline is installed correctly, optimize the layout of the air duct, avoid sudden change of pipe diameter and sharp turning, and adjust the working condition range of the fan to stay away from the resonance zone.

6. Improper Operating Condition Matching

Each fan of waste gas treatment equipment has a suitable working flow and pressure range. Long-term operation far away from the design working point will cause unstable airflow inside the volute and induce vibration. This situation is easy to happen when the opening of the air regulating damper is too small, or the actual waste gas volume changes greatly after the transformation of the VOCs treatment system.

Step-by-step Diagnosis Process for Fan Excessive Vibration

1. Record the vibration change rule: whether it appears at startup, stable operation or temperature rise stage;

2. Check whether the fan has abnormal noise, temperature rise of bearing housing and bolt loosening;

3. Check the impeller surface for dust accumulation, corrosion and damage;

4. Verify the alignment state of the motor and fan coupling;

5. Check the bearing lubrication and shock absorption parts;

6. Eliminate pipeline stress and airflow resonance factors;

7. Carry out vibration spectrum test and dynamic balancing correction if needed.

Preventive Maintenance Suggestions

Good daily maintenance can greatly reduce the risk of fan vibration failure and ensure the stable operation of waste gas treatment equipment. The technical team of Zhengzhou Puhua Technology recommends users to make a regular maintenance plan for the supporting fans of bag dust removal, desulfurization, denitrification and VOCs governance equipment.

• Clean the impeller regularly according to the characteristics of waste gas;

• Inspect the fastening parts and shock absorption components every month;

• Replace lubricating grease according to the maintenance cycle;

• Check the alignment again after equipment overhaul and pipeline modification;

• Monitor vibration data for key fans of continuous production lines.

Conclusion

Excessive fan vibration of waste gas treatment equipment is a comprehensive mechanical and aerodynamic problem. Impeller unbalance is the most common cause, while misalignment, bearing failure, loose installation, pipeline resonance and mismatched working conditions are also important factors. Accurate diagnosis before disassembly can save maintenance time and avoid secondary damage to equipment.

Zhengzhou Puhua Technology provides complete waste gas and dust treatment system solutions. Whether you need a new set of VOCs governance equipment, baghouse dust collector, desulfurization and denitrification equipment, or technical consultation on fan matching, installation guidance and fault maintenance, you can get professional technical support from the team.

If you have questions about fan selection, installation and maintenance of industrial waste gas treatment systems, feel free to contact us for technical support.