Practical Operation Experience for Liquid Ring Vacuum Pump Units

Liquid ring vacuum pump units are universal negative-pressure equipment widely used in chemical, pharmaceutical, light industry and sewage treatment industries. Forming a vacuum cavity through liquid medium, liquid ring vacuum pumps feature explosion-proof performance, moisture resistance and tolerance to tiny impurities, perfectly adapting to complex working conditions with high humidity and steam. Different from dry vacuum pumps, they deliver stable mechanical performance and low maintenance costs. This article summarizes full-process practical operation experience including startup adjustment, daily operation, maintenance and fault handling, supporting standardized and stable on-site equipment management.

Core Structural and Operational Advantages

Liquid ring vacuum pump units show outstanding adaptability in industrial scenarios, with four core advantages:

1. Excellent moisture and steam resistance: The liquid-sealed cavity structure allows direct suction of humid air and steam mixed gas without blockage or frosting failure.

2. High explosion-proof safety: No dry friction or high-temperature heat accumulation during operation, fully compliant with safety standards for flammable and explosive gas suction.

3. High working condition tolerance: Able to operate stably with tiny dust and impurities, avoiding frequent jamming and damage under fluctuating working conditions.

4. Low daily maintenance cost: Simple structure with few precision wearing parts, requiring only regular liquid inspection and cleaning for long-term stable operation.

Pre-startup Standard Inspection Specifications

Pre-operation inspection is the core premise to avoid frequent faults. Standard pre-startup checks cover four key modules:

• Working liquid level and quality inspectionWorking liquid determines vacuum forming efficiency. Excessively high liquid level causes overload and water leakage; low liquid level leads to insufficient vacuum. Operators must calibrate the rated liquid level and ensure clean working liquid to prevent pipeline and cavity blockage.

• Pipeline and sealing system inspectionCheck the tightness of intake pipelines, flanges and soft connections thoroughly. Air leakage is the primary cause of insufficient vacuum. Ensure unobstructed exhaust pipelines to avoid back pressure and operation failure.

• Transmission and power system inspectionFasten motors, couplings and transmission parts, confirm standard grounding and intact circuits. Manual jiggling ensures flexible rotor rotation without jamming or abnormal noise before formal startup.

• Cooling auxiliary system inspectionFor cooling-type vacuum units, ensure smooth cooling water circulation and stable water pressure to avoid overheating and efficiency attenuation during long-term operation.

Startup Commissioning and No-load Operation Guidelines

Standard Step-by-step Startup Procedure

Direct load startup is strictly forbidden forindustrial liquid ring vacuum pumps. The standardized startup process protects core components effectively:

1. Turn on the water circulation and cooling system and stabilize water flow;

2. Start the motor at no load and monitor vibration, noise and current status;

3. Maintain 3-5 minutes of no-load operation to stabilize the liquid ring and internal pressure;

4. Open the intake valve gradually and load production working conditions slowly.

Parameter Calibration During Trial Operation

Monitor real-time vacuum degree, operating current, body temperature and exhaust status during commissioning. Adjust valve opening and intake volume dynamically to match production negative-pressure demands and avoid process abnormalities caused by unstable vacuum values.

Load Operation and Daily Management Specifications

Working Liquid Daily Management

Long-term operation leads to impurity and oil contamination in working liquid, resulting in vacuum attenuation and cavity corrosion. Regular liquid replacement and water tank cleaning are required to maintain liquid cleanliness and stable vacuum efficiency. Shorten maintenance cycles for high-impurity working conditions.

Real-time Operation Parameter Monitoring

Focus on three typical abnormal conditions during continuous operation:

• Continuous vacuum drop: caused by air leakage, deteriorated liquid or filter blockage;

• Abnormally high current: caused by excessive liquid level, overloaded intake or rotor jamming;

• Overheating temperature: caused by poor cooling circulation and long-term full-load operation.

Special Operation Strategies for Complex Conditions

For high-humidity, high-steam and intermittent production scenarios, avoid instantaneous massive steam intake to prevent liquid ring imbalance and vacuum fluctuation. Adopt low-load standby mode instead of frequent startup and shutdown to extend equipment service life.

Standard Shutdown and Post-operation Maintenance

Step-by-step Shutdown Process

Emergency shutdown causes water backflow, impurity backflow and rotor corrosion. The standardized shutdown procedure is as follows:

1. Close the intake valve and cut off process air source;

2. Run at no load for 2-3 minutes to exhaust residual gas and impurities;

3. Cut off motor power and then close the cooling water system;

4. Drain residual water for long-term shutdown to prevent freezing and cavity rusting.

Daily Post-shutdown Maintenance

Clean surface dust and tank impurities after each shutdown. Inspect aging seals, loose pipelines and rotor wear regularly. Routine minor maintenance effectively reduces major failure rates and improves equipment stability.

Common On-site Faults and Practical Solutions

Summarize four high-frequency faults and targeted optimization solutions based on massive field operation experience:

• Insufficient vacuum and low pumping efficiencyCauses: Pipeline air leakage, turbid working liquid, unqualified liquid level, intake blockageSolutions: Check sealing performance, replace working liquid, calibrate standard liquid level and clean filter components.

• Abnormal noise and excessive vibrationCauses: Rotor scaling, loose transmission parts, severe cavitationSolutions: Clean cavity scaling, fasten accessories and optimize liquid circulation to reduce cavitation vibration.

• Overload and high operating currentCauses: Excessive liquid level, instantaneous over-intake, internal jammingSolutions: Adjust liquid level, control intake load and clean internal impurities.

• Abnormal temperature riseCauses: Failed cooling circulation, long-term full-load operationSolutions: Dredge cooling pipelines, restore water circulation and optimize operating load.

Conclusion

The stable operation of liquid ring vacuum pump units relies on standardized pre-start inspection, scientific commissioning, dynamic daily management and standardized post-operation maintenance. Featuring outstanding moisture resistance, explosion-proof performance and high condition tolerance, liquid ring vacuum pumps adapt to most industrial negative-pressure processes. Strictly following on-site practical operation specifications eliminates common faults, reduces OPEX and extends equipment service life, providing reliable and stable negative-pressure support for industrial production lines.