Compressed-air drying system

A compressed-air drying system configured to remove oil and water contained in compressed air delivered from a compressor, the system comprising:

• a pressure governor configured to output an air pressure signal to a supply passage;
• an air dryer including:
• desiccant,
• a drain port configured to drain liquid generated through regeneration of the desiccant, and
• a first drain valve device configured to be opened by the air pressure signal from the pressure governor;
• an oil mist separator including:
• a trapping portion configured to trap oil contained, as oil mist, in the compressed air,
• a drain port configured to drain liquid containing the trapped oil, and
• a second drain valve device configured to be opened by the air pressure signal from the pressure governor,
• wherein the oil mist separator is provided in a passage between the compressor and the air dryer;
• a reservoir configured to store the liquid drained from the air dryer and the liquid drained from the oil mist separator;
• a drain passage connected to the reservoir and configured to drain, to the reservoir, the liquid drained from the air dryer and the liquid drained from the oil mist separator;
• and
• a connecting portion that connects, to the drain passage, the drain port of the air dryer and the drain port of the oil mist separator,
• wherein, in an unloading mode operation, responsive to the pressure governor outputting the air pressure signal, the second drain valve device of the oil mist separator is first opened, and thereafter the first drain valve device of the air dryer is opened.