Understanding screw air compressor performance parameters is essential for selection and efficiency assessment. This article explains six core parameters. Volumetric flow rate must not fall below 95% of nominal flow. Specific power—the ratio of power to flow—is the key efficiency indicator; lower values mean better efficiency. No-load power must not exceed 35% of unit power at 0.7MPa, or 29% at 0.8MPa. Shaft power excludes external transmission losses. Discharge temperature limits: ≤110°C normally, or ≤130°C above 1.25MPa with synthetic oil. Nameplates must display at least ten items including flow rate, pressure, power, and manufacturer.

Oil carryover in screw compressor discharge degrades air quality and damages equipment. This article analyzes six root causes: separator element damage, return line blockage, low system pressure, minimum pressure valve failure, excessive oil, and poor oil quality. A step-by-step troubleshooting procedure is provided—starting with a paper test, then return line observation and pressure monitoring. Solutions include replacing damaged separators, clearing return lines (maintaining 3–4mm clearance), adjusting oil levels below the sight glass midpoint, replacing failed valves, and using qualified oil. Critical precautions include checking new elements for defects, ensuring proper grounding, and leveling the compressor for accurate oil readings.

Proper valve installation is critical for pipeline safety and reliability. This article presents 20 essential considerations across pre-installation, installation, alignment, temperature requirements, and post-installation inspection. Key steps include cleaning sealing surfaces, verifying valve compliance, and cold-testing cryogenic valves. Install valves closed with bolts evenly tightened—packing only tight enough to prevent leakage. Large gate and control valves require vertical mounting. Temperature considerations are critical: high-temperature valves need re-tightening after heating; cryogenic valves require cold-state pre-tightening and testing. Post-installation, all valves must undergo opening/closing tests. Following these guidelines ensures reliable valve performance.

Compressor rotor materials have evolved significantly. For high-speed centrifugal compressors (up to 160,000 rpm), aluminum alloys reduce vibration—imbalance force is one-third that of stainless steel. For twin-screw compressors, China adopted ductile iron rotors for better machinability and lower cost. Large compressors prefer steel. Dry screw compressors require stainless steel with advanced coatings. For single-screw compressors, oil-injected versions use steel or ductile iron with PEEK star wheels; water-lubricated versions use stainless steel or copper alloys. Temperature analysis shows rotors run cooler than bodies, ensuring safe operation. Aluminum alloys show promise for future applications.

Valves are critical components in piping systems, controlling fluids including water, steam, corrosive media, and oil. Proper selection and maintenance directly impact system safety and efficiency. This guide covers valve classification by drive type, structure, application, pressure, temperature, and size. A nine-step selection process addresses operating conditions, materials, and connection methods. Selection guidelines are provided for gate, globe, ball, butterfly, check, and diaphragm valves. Common leakage issues are analyzed across five failure points: closure components, packing seals, sealing surfaces, seal rings, and body joints—with root causes and corrective procedures specified. Understanding valve selection and troubleshooting enables engineers to optimize piping system performance and ensure long-term reliability.

Many users question whether screw air compressors require regular maintenance. This article addresses five critical consequences of neglect. An unmaintained air filter reduces intake and discharge volume; if ruptured, contaminants enter the system. A clogged oil filter increases pressure differential, causing high-temperature shutdowns. A saturated oil separator raises motor current and may rupture, leading to oil loss and overheating. Neglected oil line connections cause blockages and oil starvation. Bearings without regular greasing suffer wear that can lead to motor failure. Regular maintenance—like that required for automobiles—prevents cascading failures, ensuring reliable operation and protecting equipment investment.

Proper drainage of compressed air receivers is essential for system reliability and equipment longevity. Air receivers accumulate moisture and oil from compressed air, and improper drainage leads to tank corrosion, reduced effective volume, degraded air quality, and potential damage to compressors and downstream equipment. This article presents two drainage methods: manual drain valves and automatic drain valves (electronic and mechanical). Common issues include operator neglect and valve clogging due to rust particles. Scientific drainage practices are recommended based on operating conditions—every 8 to 12 hours for manual systems, and biweekly inspections for automatic systems. Key recommendations include establishing regular drainage schedules, conducting periodic valve inspections, and specifying larger drain ports (DN40-DN50) during procurement to prevent clogging. These practices ensure safe operation, extend equipment life, and maintain compressed air quality.

Proper motor maintenance is essential for air compressor reliability and efficiency. This paper focuses on two critical aspects: lubrication and cleaning. For lubrication, both over-lubrication and under-lubrication can cause premature failure. The proper procedure involves cleaning the grease fitting, removing the drain plug, adding new grease, and running the motor for one hour before replacing the plug. For cleaning, maintaining unobstructed airflow is vital. TEFC motor cooling fins must remain debris-free to prevent overheating and increased energy consumption. For belt-driven systems, proper V-belt tension is critical—belts should be inspected every 400 operating hours. Implementing these practices supports operational reliability and cost-effective performance.

Compressor valves directly determine system efficiency and reliability. This article covers eight critical valves: inlet, minimum pressure, safety, thermostatic, oil stop, check, solenoid, and proportional. For each, it explains working principles, functions, failure symptoms, and corrective actions. Key diagnostic techniques include: identifying inlet valve loading/unloading/oil spray causes; linking minimum pressure valve failure to safety valve discharge; annual safety valve inspection; four-pipe temperature diagnosis for thermostatic valves; oil stop valve blockage causing high-temperature trip; check valve leakage; solenoid valve sticking or coil burnout; and proportional valve adjustment. This article helps maintenance personnel build systematic valve knowledge for accurate fault location and efficient repair, ensuring long-term compressor stability.

Oil carryover in screw air compressor discharge is a common industrial fault. It degrades air quality, raises oil consumption, contaminates downstream equipment, and may cause shutdowns. This article analyzes six core causes: damaged oil separator, blocked or broken return line, excessively low system pressure, failed minimum pressure valve, overfilled oil, and poor oil quality. It provides a structured diagnosis procedure including a tissue test, sight glass observation, and pressure analysis. For each cause, corrective actions and precautions are given. Key details include maintaining a 3–4 mm gap between the return line tip and separator bottom, keeping oil level below the middle sight glass, and checking the separator seal for conductive contaminants to prevent static discharge. Most oil carryover faults can be prevented through regular inspections, correct oil selection, and timely part replacement. Proactive maintenance ensures long-term, efficient compressor operation.