Patent ID: 6769626
Filing Date: 2004-08-03
Classification: A61M,B05B

Abstract:
In an apparatus for discharging liquid, an improved device for measuring the amount of liquid that is present in the apparatus, said improved device comprising:a first member having at least one hole through which the liquid passes to be discharged from the apparatus along a direction of discharge; a second member spaced behind said first member along the direction of liquid discharge; means for providing liquid between said first and second members; said spaced first and second members establishing a volume in the apparatus between the members for receiving the provided liquid, the volume being defined in the apparatus by an area of mutual overlap of said first and second members and the amount of spacing between said first and second members in the area of overlap, said first and second members being formed to constrain the provided quantity of liquid between the members so that a dimension of the liquid quantity between the first and second members that is normal to the direction of the spacing between said first and second members is dependent on the amount of liquid in the volume, said first and second members being formed to establish a mutual capacitance that reflects the amount of liquid that is present in the volume; and a capacitance measuring unit coupled to said first and second members to determine the amount of liquid in the apparatus.