Acoustic volume indicator

An indicator for noninvasively determining the pressure of gas within an elastomeric bladder disposed in a container, comprising:

• a contactor positioned outside of and adjacent the container and configured to cause the container to vibrate;
• a detector positioned outside of and adjacent the container and configured to detect vibration from the container caused by activation of the contactor and provide an output signal;
• a processor that is configured to receive the output signal from the detector and determine information relating to the pressure of the gas within the bladder;
• and
• an indicator that provides an indication of the pressure of the gas within the bladder as determined by the processor.

A method for noninvasively determining the pressure of a gas within a container, wherein the container comprises a gas-filled bladder disposed therein, the method comprising the steps of:

• causing the container to vibrate by use of a device located outside of the container;
• detecting vibration of the container caused by the device and providing an output signal by a detector disposed outside of the container;
• and
• processing the output signal to determine the pressure of gas within bladder.