Brief Discussion on Key Points of Compressor Equipment Management, Operation and Maintenance

Since humans began using machinery, equipment management has always been indispensable. Like all other mechanical equipment, 

compressors have evolved from simple and primitive structures to sophisticated and advanced systems. Meanwhile, 

equipment management has developed from experience-based operation guidance to an independent discipline through several stages.

Stage 1: Breakdown Maintenance

Breakdown maintenance refers to repairs carried out only after machine equipment suffers damage or failure. At the early stage of industrialization, 

simple equipment was repaired by experienced operators only after breakdown and shutdown. With industrial development following the Industrial Revolution, 

the quantity and complexity of equipment increased, and maintenance work became more technically demanding. Professional maintenance personnel gradually separated from operators, 

and rudimentary equipment management systems emerged accordingly.

Stage 2: Preventive Maintenance

With the rise of large-scale socialized production, economic losses caused by equipment failures could no longer be ignored. Around 1925, 

the United States first put forward the concept of preventive maintenance, adopting a "prevention-oriented" strategy to eliminate potential failures before they occur. 

The core is to strengthen maintenance to prevent malfunctions, implement preventive maintenance as much as possible, and reduce downtime and maintenance costs. 

The main practice is to evaluate equipment conditions based on daily and periodic inspections to arrange maintenance work. Later, the industry established the Planned Preventive Maintenance System. 

Founded on maintenance complexity coefficients and maintenance cycle structures, the system formulates maintenance quotas according to equipment complexity as the basis for compiling preventive maintenance schedules. 

Apart from periodic inspections and planned repairs, it also emphasizes daily equipment maintenance.

Stage 3: Systematic Equipment Management

In 1954, General Electric Company of the United States proposed the concept of productive maintenance. It advocates systematic equipment management and targeted maintenance strategies for critical equipment to improve enterprises’ 

overall economic benefits. In the 1960s, the U.S. industrial community introduced the viewpoint of equipment logistics management. Reliability, 

maintainability and necessary logistics support schemes are considered starting from the equipment design phase. After equipment delivery, manufacturers provide comprehensive services including technical documents, 

testing solutions, spare parts supply and personnel training, 

enabling users to achieve the target of minimum life-cycle cost of equipment. Equipment management expanded from maintenance management to systematic management covering design and manufacturing, marking a new phase.

Stage 4: Comprehensive Equipment Management

Comprehensive equipment management adopts a series of technical, economic and administrative measures to manage the entire life cycle of equipment in line with enterprises’ 

macro production and operation objectives. It aims to maintain good equipment conditions, continuously improve equipment technical performance, ensure effective equipment utilization and achieve optimal economic benefits.

Two representative theories of comprehensive equipment management are Terotechnology proposed by Dennis Parks in the UK, and Total Productive Maintenance (TPM) developed in Japan on this basis. 

Their respective goals are minimum equipment life-cycle cost and maximum overall equipment efficiency.

After hundreds of years of development, theories and practices of mechanical equipment management have undergone tremendous changes. Nevertheless, 

looking at the current application status of compressors in the market, equipment management adopted by users mixes practices from Stage 1 to Stage 3, with differences arising from varying corporate technical concepts. 

Very few enterprises manage compressors in line with Stage 4 standards. Therefore, "comprehensive equipment management" is the goal that enterprises strive to achieve.

To realize the above target, namely full life-cycle equipment management, the following measures must be implemented in equipment management:
Equipment Operation
(1) Certified Operation

Before independent operation, operators must receive theoretical technical training and practical skill training. 

Only those passing assessment can obtain operation certificates issued uniformly by the equipment management department to operate equipment independently. The operation certificate shall specify the applicable equipment models.

(2) Fixed Personnel & Fixed Machine System

The fixed personnel and fixed machine system shall be implemented to strictly implement operators’ job responsibilities, ensure standardized equipment operation and daily maintenance. 

The equipment post responsibility system specifies operators’ basic obligations, rights, required skills and reward rules.

Dedicated maintenance personnel shall be assigned for shared equipment with clear maintenance responsibilities. For equipment operated by multiple people, a team leader system shall be adopted, 

and the team leader shall be responsible for equipment operation and maintenance.

(3) Shift Handover System

The shift handover system shall be implemented for critical equipment running continuously on multiple shifts. The outgoing operator shall record all equipment faults and abnormalities in detail in the shift log, 

and brief the incoming operator on operating status. Both parties conduct on-site inspection and sign the log after confirmation.

The incoming operator has the right to refuse handover if equipment abnormalities exist, records are unclear, conditions are unknown or maintenance is not completed as required. 

If equipment fails after handover due to unclear handover records, the incoming operator shall take responsibility.

In case on-site handover cannot be realized, the outgoing operator shall complete daily maintenance, secure the equipment in safe status, 

fill in the shift record and obtain signature confirmation from the person in charge for proxy handover.

Shift logs are prohibited from being torn or altered. Maintenance personnel shall collect logs regularly to analyze equipment status and optimize maintenance work. 

Equipment management departments and workshop supervisors shall conduct random inspections on the implementation of the shift handover system.

(4) Formulate Equipment Operation and Maintenance Procedures
Operation and maintenance procedures shall be formulated for precision, large-scale, rare, key and safety-related equipment.
Such procedures generally include the following contents:
On-site cleaning requirements before equipment startup;
Mandatory tools for equipment operation;
Startup procedures and precautions;
Key process parameters during equipment operation;
Contents and requirements for equipment status inspection (when necessary);
Lubrication methods and specifications;
Items, contents and frequency of spot inspection and maintenance;
Shutdown procedures, precautions and post-shutdown requirements;
Usage and adjustment standards for safety protection devices;
Causes and troubleshooting methods of common faults;
Specific work and record requirements for shift handover.
(5) Four Requirements for Equipment Operation
Neatness: Tools, workpieces and accessories are arranged neatly; safety protection devices are complete; circuits and pipelines are intact.

Cleanliness: The interior and exterior of equipment are free of heavy oil contamination. Sliding surfaces, lead screws, 

racks and gears have no oil dirt or scratches; no water or oil leakage occurs at all positions.

Lubrication: Oil filling and replacement are performed on schedule with qualified oil. Oil cans, oil guns and oil cups are complete; 

oil felts and oil lines are clean; oil level indicators are clear and oil passages are unobstructed.

Safety: Implement fixed personnel & fixed machine system and shift handover system; comply with operating procedures; use equipment reasonably; monitor abnormalities and avoid accidents.
(6) Five Disciplines for Equipment Operators
Operate equipment with valid operation certificates and comply with safety operating procedures.
Keep equipment clean and replenish lubricating oil as specified.
Abide by the equipment shift handover system.
Properly manage tools and accessories to avoid loss.
Shut down equipment immediately once abnormalities are found; promptly notify relevant personnel for inspection if problems cannot be solved independently.
(7) Four Proficiencies for Equipment Operators
Proficiency in operation: Operators shall learn equipment operating procedures, complete internship and obtain operation certificates before independent operation.
Proficiency in maintenance: Learn and implement daily maintenance and lubrication specifications to keep equipment clean and intact.

Proficiency in inspection: Master equipment structure, performance and vulnerable parts; distinguish normal and abnormal operating conditions; 

cooperate with maintenance technicians to conduct inspections and identify faults.

Proficiency in troubleshooting: Be familiar with equipment characteristics and disassembly precautions; perform basic adjustments; cooperate with maintenance technicians to eliminate faults.
(8) Three Good Practices for Equipment Management
Manage equipment well: Equipment shall be assigned to dedicated personnel; equipment cannot be used or modified without approval.
Use equipment well: Strictly implement operating procedures and avoid overloading equipment.
Maintain equipment well: Operators shall cooperate with maintenance technicians to eliminate equipment faults in a timely manner.
(9) Equipment Status Labeling
Long-term idle equipment pending retention (not scrapped) shall be sealed and marked with an Idle Equipment tag.
Equipment under maintenance shall be hung with a red maintenance tag; power switches shall be switched off and fitted with a Do Not Close Switch warning sign.
Scrapped equipment shall be marked with a black scrapped tag.
Equipment in good operating condition on site generally requires no additional labeling.
(10) Equipment Operation Records
Mandatory operation records shall be kept for large and precision equipment (Class A equipment).
Equipment Maintenance
1. Difference between Preventive Maintenance and Predictive Maintenance
(1) Preventive Maintenance
Preventive maintenance refers to planned maintenance activities implemented to avoid potential equipment failures and maintain normal operating capacity.
(2) Predictive Maintenance
Predictive maintenance is maintenance carried out by forecasting potential equipment failure modes based on data obtained from process monitoring and equipment condition monitoring.
2. Preventive Maintenance

The core contents of equipment maintenance include cleaning, inspection, lubrication, fastening, adjustment, corrosion protection, tidiness and safety. 

According to workload and technical difficulty, maintenance is divided into three levels: Routine Maintenance, Primary Maintenance and Secondary Maintenance. Primary Maintenance and Secondary Maintenance fall under periodic maintenance.

(Note: In some documents, Routine Maintenance is defined as Primary Maintenance, followed by Secondary Maintenance and Tertiary Maintenance.)
For preventive maintenance, maintenance plans including annual, monthly and (if necessary) weekly plans shall be formulated. Since maintenance items are fixed, specific maintenance contents may not be listed in the plans.
(1) Routine Maintenance
Routine Maintenance is performed by operators every day, focusing on surface upkeep.
Contents include:
Inspection before shift, during shift and after shift, including:
① Check belt tightness;
② Verify normal operation of brake switches;
③ Confirm integrity of safety protection devices;
④ Inspect positions, mechanisms and components prone to faults.
Fastening: Check and tighten loose screws.
Lubrication: Add lubricating oil in accordance with specifications.
Cleaning: Sweep and wipe equipment.
Other work: Timely drain water daily for pneumatic equipment and release pressure after work.
It is necessary to formulate routine maintenance procedures to standardize daily equipment upkeep.
(2) Primary Maintenance

Primary Maintenance is planned maintenance mainly undertaken by operators with guidance and assistance from maintenance technicians 

(or performed by maintenance technicians with operator coordination). It involves moderate technical work including inspection, adjustment, replacement and repair.

Main contents:
Partially disassemble and inspect key equipment positions as planned, thoroughly remove oil contamination and unclog oil passages.
Clean or replace oil felts, oil lines, filters and other components.
Inspect wear conditions, adjust fitting clearances of all components and fasten all positions.
Clean and inspect electrical cabinets and motors to ensure electrical installations are securely arranged and safety protection devices are reliable (undertaken by electricians).
Clean accessories and cooling devices.
General cycle: Primary Maintenance is required after every 500 operating hours.
Records shall be completed after Primary Maintenance, unresolved defects shall be noted, and acceptance inspection shall be carried out. The maintenance cycle depends on actual equipment conditions.
(3) Secondary Maintenance
Secondary Maintenance is mainly undertaken by maintenance technicians with assistance from operators (or fully completed by maintenance technicians). It requires high technical capability.
Main contents:
Partial disassembly, inspection and repair of equipment;
Repair or replace vulnerable parts and perform partial scraping and finishing;
Overhaul electrical cabinets, rearrange wiring and clean motors;
Inspect, adjust and restore equipment precision and horizontal level.

Detailed maintenance records shall be filled and acceptance implemented after Secondary Maintenance. Secondary Maintenance shall guarantee that main precision meets process requirements; 

precision that cannot be restored can be deferred to the next major overhaul. The maintenance cycle is determined according to actual equipment conditions. Secondary Maintenance can be regarded as periodic repair.

Special Notes

Major Overhaul: Major overhaul is the most labor-intensive planned repair. It requires complete disassembly of equipment, comprehensive inspection, 

repair or replacement of all worn components, calibration and adjustment of the whole system, to fully restore the original precision, performance, 

productivity and appearance (including repainting). Major overhaul can be combined with equipment technical transformation. Some documents classify major overhaul together with Secondary Maintenance under one category.

The above three-level maintenance system covers equipment spot inspection requirements. Daily spot inspection is integrated with Routine Maintenance; 

weekly periodic spot inspection is integrated with Primary Maintenance; precision inspection is integrated with Secondary Maintenance. Thus, separate specifications for spot inspection are unnecessary.

The three-level maintenance system includes traditional minor repair and intermediate repair work. Accordingly, separate minor repair and intermediate repair items are not required under this system.

Spot inspection is incorporated into the maintenance mechanism. Problems found during spot inspection shall be repaired immediately or scheduled for repair. 

Therefore, planned repairs shall be arranged between periodic Primary and Secondary Maintenance cycles as required. Alternatively, 

the schedule for Primary and Secondary Maintenance can be unfixed and determined by equipment condition monitoring (this mode belongs to predictive maintenance).

Spot inspection can also be implemented independently. Annual and monthly plans for Primary and Secondary Maintenance shall generally be formulated, listing maintenance items, contents and schedules.