CARTRIDGE WITH FILL LEVEL DETECTION
First Claim
1. A cartridge with a fill level detection system, the cartridge comprising a substantially rigid containing wall having a tubular wall portion surrounding a chamber for receiving fluid therein, a plunger or piston mounted inside the chamber and configured to seal one side of the chamber, the plunger or piston being displaceable in the chamber towards an outlet end of the cartridge, wherein the fill level detection system comprises a plurality of discrete fixed electrodes positioned along the tubular wall portion in a juxtaposed manner in a direction of displacement D of the plunger or piston, and a mobile discrete electrode member fixed to the plunger or piston and displaceable therewith, the average thickness (t) of the mobile discrete electrode member in the direction of displacement of the mobile electrode member being equal to, or less than, two times a spacing (s) between adjacent said discrete fixed electrodes.
3 Assignments
0 Petitions
Accused Products
Abstract
A cartridge (2) with a fill level detection system (10, 10′, 10″), the cartridge comprising a substantially rigid containing wall (4) having a tubular wall portion (12) surrounding a chamber (18) for receiving liquid therein, a plunger or piston (8) mounted inside the chamber and configured to seal one side of the chamber, the plunger or piston being displaceable in the chamber towards an outlet end (14) of the cartridge, characterised in that the fill level detection system comprises a plurality of discrete fixed electrodes (24, 24′) positioned along the tubular wall portion in a juxtaposed manner in a direction of displacement D of the plunger or piston (8), and a mobile electrode member (28) fixed to the plunger or piston and displaceable therewith.
32 Citations
14 Claims
- 1. A cartridge with a fill level detection system, the cartridge comprising a substantially rigid containing wall having a tubular wall portion surrounding a chamber for receiving fluid therein, a plunger or piston mounted inside the chamber and configured to seal one side of the chamber, the plunger or piston being displaceable in the chamber towards an outlet end of the cartridge, wherein the fill level detection system comprises a plurality of discrete fixed electrodes positioned along the tubular wall portion in a juxtaposed manner in a direction of displacement D of the plunger or piston, and a mobile discrete electrode member fixed to the plunger or piston and displaceable therewith, the average thickness (t) of the mobile discrete electrode member in the direction of displacement of the mobile electrode member being equal to, or less than, two times a spacing (s) between adjacent said discrete fixed electrodes.
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13. A method of determining the fill level of a cartridge comprising a mobile plunger or piston, including:
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providing the cartridge with a plurality of discrete fixed electrodes positioned along a tubular wall portion of the cartridge in a juxtaposed manner in a direction of displacement D of the plunger or piston, and a mobile discrete electrode fixed in, on or to the plunger or piston, and reading a capacitance value between each of the plurality of fixed electrodes and the mobile discrete electrode, whereby the fixed electrode that provides the strongest capacitance value indicates the position of the plunger or piston. - View Dependent Claims (14)
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Specification