Patent ID: 8561459

Claim:
A pressure sensing system for volume measurements, comprising: a container having a container opening; a chamber having a chamber opening that is sealably coupled to the container opening to form an enclosed space defined by a portion of the container and a portion of the chamber; a pressure changing device at least partially located within the chamber, the pressure changing device configured to increase a pressure of a gas substance contained within the enclosed space at a predetermined pressure; a pressure sensing device configured to measure a new pressure of the gas substance contained within the enclosed space after the pressure changing device increases the pressure of the gas substance contained within the enclosed space; a memory stored with a reference volume corresponding to a volume of the container when empty of a solid or liquid substance and a reference pressure corresponding to a pressure of the container when empty of a solid or liquid substance; and a processor configured to determine an available space volume of the container by using the reference volume, the reference pressure, and the new pressure, such that a temperature is not used to determine the available space volume of the container.