Patent ID: 8491570

Claim:
A wearable infusion pump assembly comprising: a reservoir for receiving an infusible fluid; a fluid delivery system configured to deliver the infusible fluid from the reservoir to an external infusion set, wherein the fluid delivery system includes: a volume sensor assembly configured to receive, and measure the volume of, a quantity of the infusible fluid from the reservoir, the volume sensor assembly including: an acoustically contiguous region having a volume that varies based upon the quantity of infusible fluid received from the reservoir, an acoustic energy emitter configured to provide acoustic energy at a plurality of frequencies to excite a gas included within the acoustically contiguous region for measuring the volume of the quantity of the infusible fluid, a first acoustic energy receptor for receiving at least a portion of the acoustic energy provided by the acoustic energy emitter and defining an acoustic response for each of the plurality of frequencies, and a second acoustic energy receptor for receiving at least a portion of the acoustic energy provided by the acoustic energy emitter and defining an acoustic reference for each of the plurality of frequencies; a disposable housing assembly including the reservoir, a first portion of the fluid delivery system, a first portion of a pump assembly, a first portion of a first valve assembly, and a first portion of a second valve assembly; a reusable housing assembly including a second portion of the fluid delivery system, a second portion of the pump assembly, a second portion of the first valve assembly, and a second portion of the second valve assembly; at least one processor; and a computer readable medium coupled to the at least one processor, the computer readable medium including a plurality of instructions stored thereon which, when executed by the at least one processor, cause the at least one processor to perform operations comprising: determining a phase relationship between the acoustic response and the reference for each of the plurality of frequencies, and calculating a change of volume characteristic based, at least in part, upon the phase relationship between the acoustic response and the acoustic reference for each of the plurality of frequencies; wherein the pump assembly is configured to extract the quantity of the infusible fluid from the reservoir and provide the quantity of the infusible fluid to the volume sensor assembly; wherein the first valve assembly is configured to selectively isolate the pump assembly from the reservoir; and wherein the second valve assembly is configured to selectively isolate the volume sensor assembly from the external infusion set.