Patent ID: 7722331

Claim:
A control system for an air-compressing apparatus comprising: a plurality of air compressors that compress air and discharge compressed air; a tank that stores the compressed air from said plurality of air compressors; a pressure detecting unit that detects a pressure in said tank; and a control unit that controls a discharge flow rate of said plurality of air compressors by increasing or decreasing a number of said plurality of air compressors to be operated according to the pressure in said tank detected by said pressure detecting unit; wherein said control unit controls the number of said plurality of air compressors to be operated according to a rate of increase over time of the pressure in said tank detected by said pressure detecting unit such that the number of said plurality of air compressors to be operated decreases more significantly when the rate of increase is high as compared to when the rate of increase is low, and said control unit controls such that the number of said plurality of air compressors to be operated is decreased at lower pressure in the tank, when the rate of increase is high as compared to when the rate of increase is low; said control unit calculates from the increasing rate an upper limit arrival time needed for the pressure in said tank to reach an upper limit pressure; and said control unit decreases the number of said plurality of air compressors to be operated when the upper limit arrival time is less than a predetermined time.