Fluid volume sensor

A volume detection system for determining the volume of fluid in a container, comprising:

• a container;
• an indicium mechanically linked to the container for conveying information about the configuration of the container;
• an ultrasonic transducer removably coupled to the container;
• an indicium detector mechanically linked to the transducer, said indicium detector positioned to detect the indicium on the container;
• and
• electronics in electrical communication with said transducer and said indicium detector for identifying the container through the use of the indicium and for determining the volume of fluid in the container.

An apparatus for determining the volume of a liquid within a container having a predetermined configuration, wherein a boundary exists between said liquid and a gas, said apparatus comprising:

• a transducer in sonic communication with said container for generating and subsequently receiving an ultrasonic signal through said liquid;
• circuitry in connection with said transducer for measuring the time elapsed between the generation and reception of said ultrasonic signal;
• indicator means for indicating to said apparatus said configuration of said container, wherein said indicator means comprises a photo-diode for reading a bar code located on said container;
• circuitry for converting said elapsed time between said generation and reception of said ultrasonic signal into dimensional data;
• and
• means for determining volume data representing the volume of said liquid, each value of said volume data being determined from the indicated configuration of said container in combination with a value of said dimensional data.

A method for determining the rate of change in the volume of blood in a container having a predetermined configuration, wherein a boundary exists between said blood and a gas, said method comprising the steps of:

• (a) generating an ultrasonic signal which propagates through said blood and is subsequently received by a receiver;
• (b) measuring the time elapsed between the generation and reception of said ultrasonic signal;
• (c) converting said elapsed time between said generation and reception of said ultrasonic signal into volume data representing the volume of said blood within said container;
• and
• (d) repeating steps (a) to (c) a plurality of times in order to determine the change in the volume of said blood over a specified time interval, wherein an alarm is set off when said change in the volume of said blood indicates that the rate at which blood is entering said container is lower than the rate at which blood is leaving said container.