Ultrasonic bubble detector

• US 4,418,565 A
• Filed: 12/03/1980
• Issued: 12/06/1983
• Est. Priority Date: 12/03/1980
• Status: Expired due to Term

• Current Assignee: Baxter Travenol Laboratories Incorporated
• Original Assignee: Baxter Travenol Laboratories Incorporated
• Inventors: St. John, Peter A.
• Primary Examiner(s): Kreitman, Stephen A.
• Application Number:
  US06/212,653
• Time in Patent Office: 1,098 Days
• Field of Search: 73/19, 73/61 R, 73/53, 128/663, 128/660, 128/214 E
• US Class Current: 73/19.03
• CPC Class Codes: A61M 5/365 Air detectors A61M5/1684 takes precedence; in extracorporeal blood circuits A61M1/3626
• CPC Class Codes: G01N 2291/02433 Gases in liquids, e.g. bubbles, foams
• CPC Class Codes: G01N 2291/02836 Flow rate, liquid level
• CPC Class Codes: G01N 2291/0425 Parallel to the surface, e.g. creep waves
• CPC Class Codes: G01N 2291/048 Transmission, i.e. analysed material between transmitter and receiver
• CPC Class Codes: G01N 2291/102 one emitter, one receiver
• CPC Class Codes: G01N 29/032 by measuring attenuation of acoustic waves

Abstract

Ultrasonic bubble detection apparatus utilizes a typically one-piece, rigid housing having a channel defined therein for receiving flow tubing in which bubbles are to be detected. First and second ultrasonic sending and receiving transducers are positioned on opposite sides of the channel, with an aperture communicating between each of the transducers and the channel, the aperture being filled with an elastomeric material capable of transmitting ultrasound energy between the channel and each transducer means. An air-containing slot may be positioned at the bottom of the channel to hinder the propagation of ultrasound energy through the housing from the first to the second transducer by a route other than one passing through the elastomeric material. Also, a novel shape for the apertures, and the elastomeric material filling them, is disclosed.

Claims

1. In ultrasonic bubble detection apparatus, a one-piece, rigid housing made of glass-filled polytetrafluoroethylene, a channel defined in the one-piece housing for receiving flow tubing in which bubbles are to be detected;

first ultrasonic sending transducer means positioned in said housing on one side of the channel;

second ultrasonic receiving transducer means positioned on the other side of said channel, said sending and receiving transducer means being of the type for respectively sending and receiving ultrasound energy at a frequency of 1 to 3 MHz;

aperture means respectively communicating between each of said first and second transducer means and said channel, said aperture means being filled with an elastomeric material capable of transmitting ultrasound energy between said channel and each transducer means;

electric lead means communicating from each transducer means to the exterior of said housing, and added air-containing slot means positioned in the bottom of said channel of a width too small to contain the tubing positioned within said channel and being of a depth extending below the lower edge of each of said transducer means, to hinder the propagation of ultrasound energy through said housing from the first to the second transducer by a route other than one passing through said elastomeric material, whereby tubing inserted in said channel may be in contact with said elastomeric material to provide transmission of ultrasound energy between the first and second transducers, which transmission of ultrasound energy is significantly altered by the presence of a bubble in the tubing, when compared with said tubing completely filled with liquid.

2. The ultrasonic bubble detection apparatus of claim 1 in which said elastomeric material is translucent silicone rubber.

3. The ultrasonic bubble detection apparatus of claim 1 in which each aperture means comprises a pair of apertures respectively communicating between each of the first and second transducer means and said channel;

each aperture, and the elastomeric material filling each aperture, being of a shape comprising a disc portion adjacent each of said first and second transducer means, each disc portion of elastomeric material being adhered at its outer face to a face of the adjoining transducer means, each aperture, and the elastomeric material carried therein, also comprising an elongated projection extending from said channel to the side of each disc portion opposed to the adjacent transducer means, said elongated projection of elastomeric material being integral with its adjacent disc portion of elastomeric material, whereby a bridging path of elastomeric material communicates directly from each transducer to said channel, extending inwardly of said channel to a degree sufficient to assure firm contact with flow tubing positioned in said channel.

4. The ultrasonic bubble detection apparatus of claim 1 in which each of said sending and receiving transducer means are positioned in a chamber defined by said housing, and held in said chamber by annular retention means which press against only the peripheral portions of the respective transducer means, so that outwardly-facing central portions of said transducer means face an open space.

5. In ultrasonic bubble detection apparatus, a channel defined in the one-piece housing for receiving flow tubing in which bubbles are to be detected;

first ultrasonic sending transducer means positioned in said housing on one side of said channel;

second ultrasonic receiving transducer means positioned on the other side of said channel;

aperture means respectively communicating between each of said first and second transducer means and said channel, said aperture means being filled with an elastomeric material capable of transmitting ultrasound energy between said channel and each transducer means;

said housing having an air-containing slot positioned in the bottom of said channel of a width too small to contain the tubing positioned within said channel and being of a depth extending below the lower edge of each of said transducer means, to hinder the propagation of ultrasound energy through said housing from the first to the second transducer by a route other than one passing through said elastomeric material;

each aperture means comprising a pair of apertures communicating between each of the first and second transducer means and said channel;

the elastomeric material filling each aperture comprising a shape comprising a disk portion adjacent each of said first and second transducer means, each disk portion of elastomeric material being adhered at its outer face to a face of the adjoining transducer means, the elastomeric material carried in each aperture also comprising an elongated projection extending from said channel to the side of each disk portion opposed to the adjacent transducer means, said elongated projection of elastomeric material being integral with its adjacent disk portion of elastomeric material, whereby a bridging path of elastomeric material communicates directly from each transducer to said channel, extending inwardly of said channel to a degree sufficient to assure firm contact with flow tubing positioned in said channel;

electric lead means communicating from each transducer means to the exterior of said housing, whereby tubing inserted in said channel may be in contact with said elastomeric material to provide transmission of ultrasound energy between the first and second transducers, which transmission of ultrasound energy is significantly altered by the presence of a bubble in the tubing, when compared with said tubing completely filled with liquid.

6. The ultrasonic bubble detection apparatus of claim 5 in which each elongated projection of the apertures on opposite sides of the channel, and the elastomeric material therein, is of generally oval cross section, with the longest axis of said oval cross section being positioned to be essentially parallel to the axis of flow tubing positioned in said channel.

7. The ultrasonic bubble detection apparatus of claim 5 in which said elongated projection of each aperture means is spaced toward the outer portion of said slot from the axis of each disc portion of said aperture means.