How to deal with slow pumping of screw air compressor

In view of the problem of slow pumping of screw air compressors, combined with common fault causes and solutions in industrial sites, the following is a systematic treatment guide:

1. Analysis of core failure causes

1. Reduction in gas path system efficiency
   • Air filter element blocked: Long-term use without replacement will increase the intake resistance, and the measured intake volume may be reduced by more than 30%.
   • Intake and exhaust valves are stuck: The wear of the valve plate or the failure of the spring will cause poor communication between the compression chamber and the air passage, which directly affects the exhaust volume.
   • pipeline leakage: Workshop pipeline joints are loose or corroded and perforated, and the leakage may reach 15%-20% of the total gas production.
2. Host performance degradation
   • Wear of male and female rotors: The increase in clearance leads to internal leakage, and the typical wear amount increases by 0.02mm per 10000 operating hours.
   • Bearing clearance exceeds standard: Excessive axial/radial clearance causes vibration and indirectly reduces volumetric efficiency.
3. Auxiliary system matching problem
   • Cooling system failure: Cooler fouling or fan failure causes high exhaust temperature, triggering protective shutdown.
   • Lubricating oil deterioration: Oil emulsification or viscosity decreases, affecting sealing and cooling effects.

2. Standardized process for fault diagnosis

1. basic examination(Time consuming: 30 minutes)
   • visual detection: Check the dust accumulation on the surface of the air filter element. The normal pressure difference should be <0.05MPa.
   • Audiodiagnosis: Abnormal noise during operation of the air compressor may indicate bearing or rotor failure.
   • parameter check: Compare the deviation between the pressure and temperature values of the display and the rated parameters.
2. depth detection(Time consuming: 2 hours)
   • air tightness test: Close the valve after the air storage tank is pressurized to the rated pressure. The pressure drop within 5 minutes should be <0.02MPa.
   • infrared temperature measurement: Check the temperature difference between the inlet and outlet of the cooler. The normal difference should be greater than 8℃.
   • oil analysis: Take samples to test the viscosity, acid value and moisture content of the lubricating oil.
3. Professional diagnostic tools
   • vibration analyzer: Check the bearing vibration frequency, and abnormal peaks indicate potential faults.
   • thermal imager: Identify pipeline leakage points and overheated parts.

3. Precise processing plan

1. Rapid recovery measures
   • filter replacement: Original factory replacements are used, and pressure testing is required after installation.
   • valve regulating: Adjust the pre-tightening force of the intake and exhaust valve stems to ensure the synchronization of opening and closing.
2. Host maintenance strategy
   • rotor grinding: A professional maintenance workshop conducts dynamic balance verification, and the clearance after repair should be <0.03mm.
   • bearing replacement: Choosing ceramic ball bearings can increase life by 3-5 times.
3. System upgrade plan
   • frequency conversion transformation: Install a frequency converter to achieve on-demand gas supply, with an energy saving rate of 25%-40%.
   • waste heat recovery: Using compression heat to regenerate the dryer, the comprehensive energy efficiency is improved by 12%-18%.

4. Preventive maintenance plan

1. daily inspection(Daily)
   • Check condensate discharge, lubricating oil level and leak points.
2. Quarterly maintenance
   • Replace the air filter element, oil filter and oil separator core.
   • Clean cooler fins.
3. annual overhaul
   • Check rotor clearance and calibrate pressure sensor.
   • Replace the drive belt and seals.

typical cases: The blowing capacity of a screw machine in a ceramic factory dropped by 40%. After testing, it was found that the spring of the inlet valve was broken, causing the valve to not be fully opened. After replacing the valve components, the gas production returned to 98% of the rated value, saving approximately 800kWh per day.

Through systematic diagnosis and targeted treatment, most problems with slow pumping can be solved within 24 hours. It is recommended that enterprises establish a digital twin system for equipment to achieve predictive maintenance and further reduce failure rates.