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I. Equipment inspection: To maintain the original performance of production equipment, this is a process of conducting thorough preventive inspections at regular intervals and using predetermined methods. It involves utilizing the human senses (sight, hearing, smell, taste, touch) or simple tools and instruments to check specific parts of the equipment against pre-established standards, in order to detect any abnormalities early. This allows for early identification, prevention, and correction of potential problems within the equipment; such equipment inspection is known as point inspection. Adopting predictive maintenance, which is based on inspections and utilizes condition monitoring, is the direction for reforming equipment maintenance methods. During the equipment usage phase, maintenance management is a key aspect of equipment management. To overcome the drawbacks of scheduled maintenance, condition-based maintenance should be adopted; the basis for this approach is the inspection of equipment to determine its condition, thereby providing a foundation for maintenance activities. II. Classification of inspections There are many methods for classifying inspections, but the common classification methods can be summarized into the following three types. 1. Classified by type of inspection: (1) Quality inspection: It only checks the condition of the equipment, that is, the degree of deterioration of the equipment, in order to determine the timing for its maintenance. (2) Trend-based inspection: Typically used for the inspection of equipment prone to sudden failures; it involves checking for signs of degradation in such equipment and carrying out trend management to predict maintenance times or replacement cycles. 2. Classified by inspection method: (1) Disassembly inspection. (2) Non-dismantling inspection. 3. Classified by inspection cycle: (1) Routine inspections. Daily inspections are carried out by operators, who mainly use their senses to check the condition of the equipment. When abnormal phenomena are detected and can be resolved through simple adjustments or repairs, the operators handle them on their own. If the operators are unable to resolve the issue, it is reported to professional maintenance personnel who then fix the problem. Some defects and deteriorations that do not affect normal production are addressed during regular maintenance. (2) Regular inspections. Regular inspections are planned checks carried out by maintenance personnel or equipment inspectors, using not only the senses but also various specialized measuring instruments. The inspection schedule should be coordinated with the production plan, and it should be adjusted based on past maintenance records, production conditions, the actual condition of the equipment, and experience, in order to make it more reasonable. Problems identified during regular inspections should be addressed immediately if possible; those that cannot be resolved should be included in the planned maintenance or renovation schedule. (3) Precision inspection. Comprehensive testing and inspection of equipment are carried out using precision instruments and meters, or diagnostic techniques are applied without disassembling the equipment; that is, special instruments, tools, or methods are used to measure physical parameters such as vibration, wear, stress, temperature rise, current, and voltage. By analyzing and comparing the collected data, it is possible to quantitatively determine the technical condition of the equipment and the degree of its degradation, thereby assessing the necessity for repair or adjustment. Precise inspections are generally carried out on a regular or irregular basis by dedicated maintenance personnel (including engineering technicians) for inspection and measurement. The main inspection methods for precision inspections are as follows: (1) Non-destructive testing: used to detect defects, cracks, etc. in components. (2) Vibration noise measurement: Mainly used for the regular assessment of imbalances, shaft misalignment, bearing wear, etc., in high-speed rotating machinery. (3) Ferrography and spectroscopic analysis: Used for the regular determination and analysis of the quantity, size, and shape of metal particles in lubricants. (4) Oil sampling analysis: Used to analyze the degree of degradation of lubricating oils, hydraulic oils, and transformer oils. (5) Stress, torque, and torsional vibration testing: Used for drive shafts, pressure vessels, crane girders, etc. (6) Surface non-destructive testing: For areas that cannot be inspected with ordinary tools, specialized techniques and instruments are used for inspection. (7) Relay and insulation testing: Used for periodic protection testing of transformers, motors, switches, cables, etc. (8) Switch-related tests: Measurement of the contact resistance value of switches such as SF6 switches. (9) Electrical system testing: includes thyristor leakage testing, drive protection testing, as well as tests on contact pulses and characteristics of the drive system. III. Contents of inspections 1. Contents and methods of routine inspections Routine inspections involve checking and monitoring ten key aspects of equipment, including pressure, temperature, flow rate, leaks, lubrication status, abnormal noises, vibrations, cracks (breakages), wear, and looseness. Its methods primarily rely on the five senses of sight, hearing, touch, taste, and smell, with some important areas being measured using simple instruments and tools. 2. Contents of regular equipment inspections (1) Regular inspections of the equipment without disassembly ； (2) Equipment disassembly inspection ； (3) Degradation tendency ； (4) Precision testing of the equipment ； (5) Precision inspection and adjustment of the system ； (6) Regular component analysis of oil in the tank and replacement/addition thereof ； (7) Replacement of components, repair of deteriorated parts, etc. 3. Main tasks of equipment inspection Although the contents of equipment inspection vary greatly depending on the type of equipment and operating conditions, several key steps must be carefully carried out in any equipment inspection: (1) Identifying the inspection points. Generally, the key parts and weak points of the equipment are listed as inspection points. Choose the sensitive points of equipment vibration as much as possible ； The key points closest to the core of the device and the vulnerable areas prone to degradation ； (2) Determining the inspection items means specifying the contents of inspections for each inspection area (point) ； (3) Establish judgment criteria for inspections. Establish criteria for determining whether the technical condition of each inspection item is normal, based on the technical specifications and practical experience provided by the manufacturer ； (4) Determine the inspection cycle. The inspection cycle is determined based on the importance of the checkpoints in maintaining production or safety as well as the characteristics of the manufacturing process, taking into account past experience with equipment maintenance ； (5) Determine the methods and conditions for inspections. Based on the requirements of the inspection, determine the methods and operating conditions to be used for each inspection item ； (6) Identify the inspectors. Identify the persons responsible for various types of inspections (such as routine inspections, periodic inspections, and special inspections), and determine who is in charge of each type of inspection ； (7) Prepare inspection checklists. Form fixed tables containing various inspection checkpoints, items, cycles, methods, criteria for judgment, as well as the designated recording symbols, for use by inspectors during inspections ； (8) Keep proper inspection records and conduct analysis. Inspection records are the original materials used to analyze equipment condition, establish equipment technical files, and prepare equipment maintenance plans ； (9) Ensure proper management of inspections, and establish a rigorous equipment inspection management system ； (10) Provide proper training for inspection personnel. The 5th 2024 Symposium on Catalytic Hydrogenation Processes and Continuous Flow Technology -- Nanjing. The \"five fixed elements\" for equipment inspection refer to fixed location, fixed method, fixed standards, fixed frequency, and fixed person in charge. This is the most essential element of equipment inspection work. 4. Inspection tasks and responsibilities of full-time inspection personnel: (1) Establishing basic materials such as inspection standards, lubrication standards, component coding, and standard working time quotas. (2) Prepare various plans and record performance. (3) Carry out inspection tasks carefully as planned, provide guidance on inspection and maintenance work to operators or crew members, and have the authority to supervise and inspect; any issues found must be investigated and resolved promptly. (4) Prepare a schedule of maintenance tasks and list the monthly maintenance plan. (5) Based on the inspection results and maintenance needs, prepare a cost budget plan and utilize it. (6) Based on the expected usage plan for spare parts and the requirements of maintenance schedules, prepare plans for the required maintenance materials as well as carry out the preparatory work for material procurement. (7) Collect equipment status information for trend management, quantitative analysis, and to determine the degree of component degradation. (8) Participate in accident analysis and handling, and propose suggestions for repairing, preventing, and improving equipment performance. (9) Provide maintenance records to conduct performance analysis regarding faults, repairs, costs, etc., and propose measures and suggestions for improving the equipment. (10) Participate in precision inspections. IV. Management of Degradation Trends To understand the degree of degradation of the target equipment as well as the trends in the amount of deterioration, it is necessary to monitor its fault parameters, conduct regular measurements of the degree of degradation, manage the quantitative data related to equipment degradation, and analyze the causes and locations of degradation. This allows for the control of the degradation trends of the target equipment, thereby predicting its service life and enabling repairs to be carried out in the most economical manner. The implementation steps for degradation tendency management are as follows: (1) Identify the project: that is, select the equipment subject to tendency management and the management items. (2) Formulate a plan: Design and prepare trend management charts. (3) Implementation and recording: Record the measured data and create trend management curve charts. (4) Analysis and countermeasures: Conduct statistical analysis to identify patterns of degradation, predict replacement and repair cycles, and propose improvement measures. V. Contents of equipment technical diagnosis: This is a quantitative testing of the equipment carried out by professional technicians, commissioned by specialized inspectors. It mainly includes the following: (1) Mechanical testing: vibration, noise, ferrography analysis, acoustic emission. (2) Electrical testing: insulation, dielectric loss. (3) Oil quality testing: contamination, viscosity, infrared oil analysis. (4) Temperature detection: point temperature, thermal imaging. VI. The “five key elements” for inspecting equipment and the “four principles of maintenance” for equipment 1. The “five key elements” for inspecting equipment (1) Tightening ； (2) Cleaning ； (3) Add grease ； (4) Spare parts management ； (5) Carry out maintenance as planned. 2. The “four maintenances” of equipment (1) Maintain the equipment’s clean appearance ； (2) Maintain the structural integrity of the equipment ； (3) Maintain the performance and accuracy of the equipment ； (4) Maintain the degree of automation of the equipment. VII. The five-layer protection system for equipment: To ensure the proper operation of the equipment, daily inspections, regular inspections, precise inspections (including accuracy tests), technical diagnostics of the equipment, and equipment maintenance are combined to form a comprehensive protection system for it. It can be specifically divided into the following five levels: 1. Daily inspections by operators. Through these daily inspections, if any abnormalities are detected, in addition to promptly notifying specialized inspection personnel, one can also take action to resolve the issues themselves and carry out minor repairs; this constitutes the first line of defense against accidents. 2. Professional inspection by specialized inspectors relies mainly on the senses or the use of certain tools and simple instruments to carry out inspections. It involves targeted inspection of key equipment, identifying and eliminating potential hazards, analyzing and resolving faults, and organizing their repair – this constitutes the second line of defense. 3. The precise inspection and accuracy testing by professional technical personnel involve conducting rigorous, detailed inspections, measurements, adjustments, and analyses of the equipment on a regular basis, in addition to routine inspections and periodic professional inspections; this constitutes the third line of defense. 4. Equipment technical diagnosis: Equipment technical diagnosis involves conducting systematic tests on equipment while it is in operation or without disassembling it, thereby assisting professional inspectors in making decisions and preventing accidents; this represents the fourth level of protection. 5. Equipment maintenance: Through the aforementioned four layers of protection, it is possible to understand the patterns of equipment degradation, thereby slowing down this process and extending the lifespan of the components. However, sudden failures can still occur, and in such cases maintenance is required. The level of maintenance skills directly affects the rate at which equipment deteriorates; therefore, there is a need for a maintenance team with high skill levels and a strong sense of responsibility. It can be said that equipment maintenance is also an important part of the inspection system, representing the fifth line of defense for equipment.