Patent ID: 8453595

Claim:
A jetting apparatus for jetting individual droplets of viscous medium onto a substrate, comprising: a jetting device having a jetting outlet through which said droplets are jetted, a vacuum ejector configured to produce a negative pressure for producing a flow of air past the jetting outlet for removing viscous medium residue at the jetting outlet, a receptacle for receiving viscous medium residue transported by said air flow away from the jetting outlet, an air flow path for said air flow between said jetting outlet and said vacuum ejector, via said receptacle, an air flow meter for measuring the air flow in said air flow path, said air flow meter including a flow sensor positioned in the air flow path between said jetting outlet and said vacuum ejector, said air flow meter being arranged for outputting an air flow signal representative of the air flow in the air flow path, and a processor arranged for receiving said flow signal from the air flow meter, evaluating said flow signal, and outputting an indication of a status of the jetting apparatus.