Blow the Lid Off!

 

Save thousands of dollars a year by maintaining your compressor.

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Energy use may account for up to 90 percent of the total costs for compressed air production. If a system is not operating at peak efficiency, energy consumption goes up as air leakage and pressure drops occur. A preventive maintenance program will help optimize efficiency and keep minor problems from becoming major ones. A well-maintained system can save 20 percent to 50 percent of the cost to run it, according to Efficiency Maine.

Good maintenance practices

A good maintenance program should follow the manufacturer’s specifications and guidelines regarding frequency of procedures and types of lubricants. Designate one employee to manage the program.

Daily inspections of oil and fluid levels are recommended to ensure they are at the specified levels. Cleaning and changing air filters regularly will extend the life of oil and other fluids. Other filters should be checked regularly as well; in one case, a dirty coalescing filter resulted in an additional compressed air energy cost of $1,265 per year.

Operating conditions, such as the level of contaminants in the facility’s air, will determine how often filters and separators should be changed; however, it is recommended that air line filters be inspected annually and replaced when pressure drop exceeds 2 to 3 psid. The air lubricant separator should be changed when pressure drop exceeds 10 psid in the case of a lubricant-injected rotary screw compressor.

The following table provides a summary of tasks in a standard program for an air compressor system.

 Standard Maintenance Program for Air Compressors
ComponentTasks
Air compressor
  • Replace air, oil, and panel filters, as needed
  • Replace separator element
  • Inspect electrical components
  • Change oil or top-off as required
  • Cooler blowout
  • Wipe down exterior
  • Check belts for wear every 400 hours of operation
  • Check motor for proper lubrication and cleanliness
Dryer
  • Blow out condenser
  • Inspect electrical components
  • Clean drain trap and check open/close position
  • Wipe down exterior
Filter
  • Inspect and replace element as required
  • Clean condensate drain
  • Wipe down exterior
Condensate separation systems
  • Inspect for proper installation
  • Wipe down exterior
Receiver tank
  • Inspect safety relief valve, pressure gauge, and drain valve
  • Check for contamination in the air line from the compressor cylinder to the air receiver
Water cooling system
  • Check water quality (pH and total dissolved solids), flow, temperature
  • Clean and replace filters and heat exchangers
Air cooling system
  • Check fan for clogging
  • Check to ensure proper water training is taking place

A good maintenance program should also include quarterly air audits to find large leaks and other problems. Annual inspection for leaks using ultrasonic equipment is recommended. Because typical compressed air systems have leak loads in the range of 10 to 50 percent of the compressor capacity, leaks should be kept below 10 percent of the facility load. Check for system leaks in lines (especially joints), fittings, clamps, valves, hose disconnects, regulators, filters, lubricators, gauge connections and end-use equipment.

Keep it clean

The cleanliness of the entire system and its components is critical to efficient operation. For reciprocating compressors, keeping water jackets clean helps maintain the proper operating temperature. Measuring the temperature difference between inlet and outlet water pipes will determine when the water jacket requires cleaning. The motor’s air passages must also be kept clean and free of obstruction, and cooling fins must be kept free of debris. If motors become overheated, their operating life is reduced, and energy consumption increases. Energy use also increases if air treatment equipment—filters, dryers, aftercoolers and separators—are not kept clean.

Benchmarking the system periodically (by tracking power, pressure and flow) will help you determine if the maintenance program is working. If power increases at a specific pressure and flow, this indicates the air compressor system is not operating at full capacity. Identify problems and adjust the maintenance program as needed.

For further information see the U.S. Department of Energy’s Improving Compressed Air System Performance, A Sourcebook for Industry, Maintenance of Compressed Air Systems for Peak Performance.