Air compressor acceptance inspection is a critical phase in equipment procurement, directly impacting operational reliability. This paper outlines a structured approach aligned with contractual and technical requirements. Key elements include pre-acceptance planning, performance benchmarks such as pressure, flow, power consumption, and air quality. Inspection relies on calibrated tools—sound level meters, infrared thermometers, pressure transmitters, particle counters, oil sensors, dew point sensors, power meters, and flow meters. The methodology covers functional checks of system configuration, safety devices, and post-treatment equipment. Documentation transfer—including schematics, manuals, certificates, and parts lists—is essential. A systematic acceptance framework ensures equipment conformity, identifies improvement areas, and supports long-term supplier collaboration.

LONTREX's 90MPa hydrogen compressor achieves 100% domestic core components, enabling China's self-sufficient hydrogen refueling stations.

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.

Piston compressors are widely used in petroleum, chemical and gas transmission for their high pressure and efficiency. As equipment grows larger and parts more costly, operation and maintenance skills have become critical. This paper analyzes energy-saving and safety issues from process design, operation management and maintenance technology. It points out that unreasonable layout such as insufficient cooler spacing, small buffer tanks and lack of mist eliminators leads to liquid hammer and ammonia carryover. Operators should enhance inspections and identify anomalies including noise, vibration and temperature changes. The article also details overhaul methods for seven key components: frame, cylinder, crankshaft, valve, piston ring, piston rod and piston. A real accident case of piston rod fracture leading to explosion is cited for warning. This study helps enterprises build scientific operation and maintenance systems to ensure safe, energy-saving and stable long-term operation.

"Magnetic stainless steel" (commonly called "stainless iron") is an industrial term for martensitic and ferritic stainless steels such as 409, 410, 430, and 444. Their key feature is magnetism. In contrast, austenitic grades like 304 and 316L are non-magnetic. This article compares the two types from three perspectives: microstructure, chemical composition, and magnetic properties. Martensitic grades (0.1–0.45% C, 12–14% Cr) are hardenable by heat treatment, reaching up to HRC 50, and are used for valves, cutters, and medical instruments. Ferritic grades (<0.15% C, 12–30% Cr) offer better corrosion resistance than martensitic types but suffer from 475°C embrittlement and sigma phase brittleness. Austenitic grades (18% Cr + 8–11% Ni) provide the highest corrosion resistance and are the most widely used. The article provides three simple identification methods: magnetic test, spark test, and copper sulfate test, helping users avoid material selection errors.

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.