×

Reservoir volume sensors

  • US 6,210,368 B1
  • Filed: 04/30/1998
  • Issued: 04/03/2001
  • Est. Priority Date: 04/30/1998
  • Status: Expired due to Term
First Claim
Patent Images

1. A drug delivery device comprising:

  • a housing;

    an expansible reservoir within the housing for containing a supply of drug, the reservoir defining a volume;

    a propellant contained in the housing as both a liquid phase and a vapor phase so as to maintain a substantially constant vapor pressure force on the reservoir as the reservoir volume changes;

    a capacitor disposed within the housing, the capacitor having a capacitance and comprising an absorbent dielectric for absorbing the liquid phase of the propellant and having dielectric properties that vary with the amount of absorbed liquid phase of the propellant, whereby the capacitance of the capacitor changes with variations in the reservoir volume.

View all claims
  • 2 Assignments
Timeline View
Assignment View
    ×
    ×