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.

As a core clean energy source, natural gas is widely used in power generation, heating, industrial manufacturing and urban gas systems. Its production, gathering and transportation highly depend on stable and reliable power equipment. Centrifugal air compressors play an irreplaceable role in the natural gas industry due to their high efficiency, large flow rate and smooth operation. This article introduces the key functions of centrifugal air compressors in compressed air supply, natural gas production, pipeline transportation and boosting stations, highlighting their value in ensuring safe, stable and efficient natural gas operations.

Against the rising natural gas demand and expanding long-distance pipeline network in China, compressors are critical equipment that directly determines the operational stability and supply reliability. Centrifugal and reciprocating compressors are most widely used, but often suffer unplanned shutdown, performance loss and mechanical damage due to equipment, electrical, operational and human factors. This paper identifies typical failure causes of the two compressors, analyzes root causes from mechanical faults, control systems, external conditions and personnel management, and proposes targeted countermeasures to support safe, efficient operation and failure reduction.

Natural gas compressors are the core power equipment for natural gas production enterprises, with their operating status directly determining the stability and safety of the entire production process. This guide focuses on reciprocating natural gas compressors (the most widely used type in the natural gas industry) and elaborates on a scientific graded maintenance system to ensure efficient operation, extend service life and reduce operational costs.

This article serves as a comprehensive introduction to compressors, detailing their definition, diverse industrial applications, and systematic classification. Compressors, or air compressors, are machines that increase gas pressure for use as power sources, in refrigeration, chemical synthesis, gas transportation, and refining processes. The article explains the various classifications of compressors, with a focus on piston compressors, which are categorized by cylinder orientation, number of stages, arrangement, piston action, discharge pressure, capacity, speed, drive type, cooling method, and transmission. Specialized types such as booster and recycle compressors are also defined. Fundamental pressure concepts—including atmospheric, gauge, absolute pressure, and vacuum—are clarified to establish a foundational understanding of compressor operation. This guide provides essential knowledge for professionals working with compressors across industries.