APPARATUS AND METHOD FOR DETECTING FAULTS IN CAN END SEALANT DEPOSITING MACHINE

2070644 9108544 PCTABS00005 The present invention detects sealant deposit faults by detection of a quantity related to sealant flow within the valve chamber of the needle valve employed in the sealant depositing machine. A proximity detector (120) indicates to an electronic controller (100) when a can end (30) is in position for depositing the sealant. The electronic controller preferably monitors the pressure within the valve chamber (26) during at least one predetermined interval of time during the open and close operation of the needle valve (27). Upon detection of a pressure abnormality during one of these predetermined intervals of time, the electronic controller generates a reject signal which enables the transport mechanism to remove that particular can end from the stream of can ends going to the next station and place it in a reject pile (38). The monitoring takes place during an initial opening period of the needle valve, and during a time when the sealant flow is relatively steady. The rate of flow of sealant into the controllable valve may also be measured directly or measured from the pressure difference measured on opposite sides of a flow restrictor (117).