METHOD AND APPARATUS FOR CONTROLLING NUMBER OF OPERATED AIR COMPRESSORS

摘要

PROBLEM TO BE SOLVED: To supply compressed air of stable pressure without falling less than a lower limit value under pressure even if load sharply fluctuates, and to prevent excess operation and thereby to reduce an energy cost. SOLUTION: A flow rate F of the compressed air fed from an air tank 2 to a load is measured. When measured flow rate Fpv reaches a nearest stage increase, one of air compressors 1 not in a loaded state is made to be a loaded state in favor of an air compressor in an unloaded stage. A flow rate changeΔF of the compressed air fed from the air tank 2 to the load is calculated from a previous value and a present value of the measured flow rate Fpv. A time where the present flow rate F reaches the nearest stage increase flow rate from the flow rate changeΔF is calculated as a stage increase point arrival time t. When the stage increase point arrival time t is shorter than a rising time of the air compressor 1, one of the air compressors 1 in a stop state is started to be in an unloaded state. COPYRIGHT: (C)2003,JPO