Method and apparatus for monitoring passage of final blow and cooling air

摘要

Apparatus for monitoring application of air through a dual-stage blowhead (18) to blow mold a container includes a first solenoid valve (32) for applying final blow air through a blowhead to a container in a mold (12, 14) and a second solenoid valve (34) for applying finish cooling air through the blowhead around the finish of the container in the mold. Electronic circuitry (36) is coupled to the first and second solenoid valves for detecting timing of application of first and second electrical valve control signals to the valves. Air pressure sensors (40, 42) are operatively coupled to the first and second solenoid valves for generating associated electrical signals indicative of timing of application of air by the first and second solenoid valves to the blowhead. Electronic compare logic (38) is responsive to the timing of the valve control signals relative to the sensor signals for indicating operating condition of the valve, preferably by comparing timing of the valve control signals to timing of the sensor signals to indicate malfunction or potential malfunction at the valves.