Fluid volume sensor

• US 5,303,585 A
• Filed: 10/31/1991
• Issued: 04/19/1994
• Est. Priority Date: 10/31/1991
• Status: Expired due to Fees

• Current Assignee: JTL Medical Corporation
• Original Assignee: JTL Medical Corporation
• Inventors: Lichte, Leo J.
• Primary Examiner(s): Cuchlinski, Jr., William A.
• Assistant Examiner(s): Bennett, G. Bradley
• Application Number:
  US07/785,792
• Time in Patent Office: 901 Days
• Field of Search: 73/149, 73/290 V, 73/290 B, 73/114, 367/908, 364/564, 364/509, 364/571.07
• US Class Current: 73/290.00V
• CPC Class Codes: A61M 1/3623 Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3627 Degassing devices; Buffer reservoirs; Drip chambers; Blood filters
• CPC Class Codes: A61M 2205/3389 Continuous level detection A61M2205/3393 takes precedence
• CPC Class Codes: G01F 23/2962 Measuring transit time of reflected waves
• CPC Class Codes: G01F 25/20 of apparatus for measuring liquid level
• CPC Class Codes: Y10S 367/908 Material level detection, e.g. liquid level

Abstract

A volume sensing system includes electronic circuitry which is electrically connected to an ultrasonic transducer. The transducer is affixed by means of an adaptor to the base of a container having a known configuration. The container holds a liquid and a gas so that a liquid-gas boundary is formed within the container. The transducer generates ultrasonic pulses which propagate through the liquid, are reflected at the liquid-gas boundary, and are received again by the transducer. The received return pulse is converted into an electrical signal which is analyzed by the electronic circuitry to determine the level of the liquid within the container. The level of the liquid within the container is then employed to determine the volume of the liquid within the container in accordance with the configuration of the container. In a preferred embodiment, the adaptor includes an indicator which may be used to identify the configuration of the container.

Claims

1. An adaptor for providing an interface between a container having a predetermined configuration and a transducer for generating an ultrasonic pulse, wherein:

said adaptor is formed to affix to said container of said predetermined configuration and to said transducer so that said adaptor may be used only to connect said container and said transducer, said transducer being in sonic communication with said container when said transducer is affixed to said container by way of said adaptor, wherein said transducer generates an ultrasonic signal through said liquid in order to measure the volume of said liquid in said container; and

said adaptor includes an indicator which identifies said configuration of said container to which said adaptor connects, said indicator including circuitry which is capable of transmitting data for identifying said adaptor and said predetermined configuration of said container.

2. 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.

3. A volume detection system as in claim 2 further comprising an adaptor for providing an ultrasonic coupling between the transducer and the container.

4. A volume detection system as in claim 3, wherein said adaptor comprises a first unique complementary surface structure which complements a corresponding second unique surface structure on a container, so that the adaptor is only functionally mountable on a container having the second unique surface structure.

5. A volume detection system as in claim 4, wherein said indicium is disposed on the adaptor.

6. A volume detection system as in claim 5, wherein said indicium comprises a bar code.

7. A volume detection system as in claim 6, further comprising a bar code reader on the transducer for reading the bar code on the adaptor.

8. 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.

9. 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.