Patent ID: 8869612
Filing Date: 2014-10-28
Classification: A61M,G01F

Abstract:
1. A medical fluid system comprising: a container holding a fluid at a level; a power source that supplies an input signal at a selected operating frequency; a radio frequency level sensor operably connected to the container and including an emitting electrode and a receiving electrode, the electrodes operating as a transmission line having an electrical impedance that varies with the level or volume of the fluid in the container; a bi-directional coupler operably connected to the sensor, the coupler receiving the input signal and outputting an incident signal and a reflected signal, the incident signal including a first phase and the reflected signal including a second phase; and a phase detector that receives the first phase and the second phase and outputs a difference signal representing a difference between the first phase and second phase, wherein the difference signal is associated with the level or volume of the fluid in the container.