The air dryer's purpose is to remove the moisture from compressed air to prevent corrosion, freeze, and other damaging effects. So to ensure the reliable and efficient operation of the air dryers, regular maintenance is mandatory.
This article will provide air dryers working principle and procedures for maintaining , encompassing daily, monthly, and annual intervals.
Air Dryer Working Principle
Air Dryers are designed to absorb moisture from compressed air. The dryers have two towers, each tower contain desiccant beads, which alternate between drying and regenerating modes, with the continuous stream of dry air on dryer's outlet. During the normal operation, wet air passes through the on line tower and water vapor from the air is absorbed on the desiccant beads.
While air is being absorbed in online tower, the moisture on the desiccant in the offline tower is removed by a process called regeneration. After an initial rapid depressurization, a portion of dried air from the online tower passes over the desiccant bed and carries the moisture off the bed and out to the dryer's exhaust.
The continuous, alternating process of absorption and desorption is controlled using timer that switches the towers in a specific timed sequence. The Most dry compressed air dew points are accomplished through continuous switching and operation of this dryer. (reference ingersollrand)
Daily Maintenance:
- Visual Inspection: Conduct a thorough visual inspection of the air dryer system for any visible signs of leaks, corrosion, or damage. Check devices connected to the air dryer, pre-filters and after-filters, gauges, pipes and electric wires for wear and tear.
- Moisture Measurement: Use a hygrometer to measure the outlet temperature and dew point of the dried air. Compare the results with the manufacturer's specifications to ensure optimal moisture removal.
- Condensate Drain: Drain the condensate from the air dryer's pre-filters and after-filters, to prevent water accumulation and potential damage to the system. Ensure the drain valves are functioning correctly and are not leaking.
Monthly Maintenance:
- Air Filters Replacement: Replace the air pre-filters at the inlet and air after-filters at the outlet of the air dryer to prevent moisture, condensate, Clog and dirt. (Confirm this point with the manual provided from the manufacturer).
- Desiccant Inspection: Check the Desiccant of air dryers, check their condition if they need to be replaced.(Confirm this point with the manual provided from the manufacturer).
- Purging Filters Replacement: Check purging filters of the air dryer, replace them if needed to prevent dust and debris. (Confirm this point with the manual provided from the manufacturer).
Annual Maintenance:
- Comprehensive Inspection: Conduct a thorough inspection of the instrument air package, including the compressor, air dryer, connections and electric system. Check for any loose connections, corrosion, or wear on hoses, belts, and other components.
- Air Receiver Tank Inspection: Inspect the air receiver tank for corrosion, leaks, or other damage and check auto drain operation.
- Auto Drain Inspection: Check the auto drain device which is connected to the air receiver tank, its purpose is to auto drain any condensate which is accumulated in the air receiver tank.
- Desiccant Replacement: Replace the Desiccant of air dryer, Most problems of air dryer comes from the melted desiccant.
**Reminder: Always read the instructions of the air dryer manufacturer.
Maintenance Logs and Troubleshooting
- Maintenance Log: Keep a detailed maintenance log of all inspections, repairs, and replacements performed on the air dryer system. This log serves as a valuable record for tracking maintenance intervals and identifying potential issues.
- Troubleshooting: If any issues arise with the air dryer system, refer to the manufacturer's manual for troubleshooting procedures.
Common problems include:
- Desiccant melt
- Excessive condensate production
- High outlet moisture content
- Leaks or damage to the system
- Compressor failure
Air Dryer Maintenance Procedures in General
- Take all the precautions needed for safety prior to work commencing.
- Check your operating conditions for inlet flow, inlet pressure, and inlet temperature.
- Check the readings of tower pressure gauge, Are the readings within operating tolerance?.
- Check tower pressure gauges for proper dryer cycling.
- Check that there is no condense discharged from pre-filters, replace them if needed.
- Verify that pressure in the purging tower is 3.5PSIG or less. (You have to read the manufacturer instructions of the unit).
- Check and verify the pre-filters and after-filters differential pressure is within operating limits.
- Check sequence of operations and the dryer cycle (i.e. drying, depressurizing, regenerating, heating, and cooling).
- Check tower temperature gauges during the third and fourth hour of the regeneration cycle.(You have to read the manufacture instructions of the unit).
- Check the pilot air filter element and clean it.
- Check the outlet dew point of the air dryer.
- Check the Blow down relief valves of the air dryer.
- When you are done with all maintenance procedures, refer to operation procedures for start-up.
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