Image Number 5 for United States Patent #6711507.
A flow meter is installed in a supply line of compressed air connected with air-driven devices in a compressed air circuit and measures a flow rate of compressed air in the supply line. A monitor computer receives measured flow rate data from the flow meter. The monitor computer includes an operational state identifying means for identifying a current operational state of the air-driven devices from a plurality of categorized operational states of the air-driven devices. The monitor computer further includes an air leakage determining means for determining a level of leakage of compressed air in the compressed air circuit through comparison of the measured flow rate data with a corresponding one of a plurality of master flow rates, which corresponds to the current operational state of the air-driven devices identified by the operational state identifying means.