System and method of evaluating or calibrating a bubble detector

• US 7,013,703 B2
• Filed: 12/31/2003
• Issued: 03/21/2006
• Est. Priority Date: 03/20/2001
• Status: Expired due to Term

• Current Assignee: TherOx Incorporated (Asahi Kasei Corporation)
• Original Assignee: TherOx Incorporated (Asahi Kasei Corporation)
• Inventors: Patterson, William R., Creech, Jeffrey L., Derek, Daw J.
• Primary Examiner(s): RAEVIS, ROBERT R
• Application Number:
  US10/750,428
• Publication Number:
  US 20040154374A1
• Time in Patent Office: 811 Days
• Field of Search: 261/29, 261/72.1, 356/243.2, 137/565.18, 137/154, 73/10.1, 73/10.2, 73/10.3, 73/10.6, 738/656, 73/240.1, 73/17.3
• US Class Current: 73/1.73
• CPC Class Codes: A61M 1/32 Oxygenators without membranes
• CPC Class Codes: A61M 1/362227 the interface providing means for actuating on functional elements of the cassette, e.g. plungers
• CPC Class Codes: A61M 1/36224 with sensing means or components thereof
• CPC Class Codes: A61M 1/362262 Details of incorporated reservoirs
• CPC Class Codes: A61M 1/362265 Details of valves
• CPC Class Codes: A61M 1/3623 Means for actively controlling temperature of blood
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 2202/0476 Oxygenated solutions
• CPC Class Codes: A61M 2209/02 Equipment for testing the apparatus
• CPC Class Codes: G01N 2291/015 Attenuation, scattering
• CPC Class Codes: G01N 2291/02433 Gases in liquids, e.g. bubbles, foams
• CPC Class Codes: G01N 2291/02466 Biological material, e.g. blood
• CPC Class Codes: G01N 35/08 using a stream of discrete samples flowing along a tube system, e.g. flow injection analysis

Abstract

A bubble detector utilizes an ultrasonic transducer to sample bubbles as they pass the transducer. The envelope of the return signal is analyzed to determine the volume of each sampled bubble. If the total volume of bubbles sampled within a certain period of time exceeds a desired maximum volume, the bubble detector may initiate a system shut down. A bubble detector can be evaluated or calibrated by introducing bubbles into a conduit, detecting the bubbles introduced into the conduit using visual inspection or a bubble detector of known resolution and comparing the results with the examination of a bubble detector under evaluation.

Claims

1. A system for evaluating or calibrating a bubble detector, comprising:

a conduit adapted to pass a flow material therethrough, wherein the conduit is configured for passing flow materials of different viscosities;

a pump operatively coupled to the conduit to pump the flow material through the conduit;

a bubble-forming device operatively coupled to the conduit, the bubble-forming device being adapted to introduce bubbles into the flow material passing through the conduit; and

a bubble detector to be evaluated positioned to examine the bubbles in the flow material passing through the conduit,

wherein the bubble-forming device comprises;

a connecting device operatively coupled to the conduit;

a bubble-forming capillary adapted to be positioned within the connecting device in communication with the flow material passing through the conduit; and

a bubble-pumping device operatively coupled to the bubble-forming capillary, the bubble-pumping device adapted to deliver a bubble-forming material to the flow material in the conduit through the bubble-forming capillary to create bubbles in the flow material,

wherein the capillary comprises;

a proximal portion operatively coupled to the bubble-pumping device and a distal portion slidably positioned within the connecting device.

2. The system, as set forth in claim 1, comprising:

an evaluation device positioned to examine the bubbles in the flow material passing through the conduit.

3. The system, as set forth in claim 2, wherein the evaluation device comprises:

a previously evaluated bubble detector having a known bubble detection resolution.

4. The system, as set forth in claim 2, wherein the evaluation device comprises:

an inspection device adapted to record bubbles finned by the bubble-forming device.

5. The system, as set forth in claim 4, wherein the inspection device comprises a camera operatively positioned proximate to bubble-forming device.

6. The system, as set forth in claim 1, wherein the pump comprises a peristaltic pump.

7. The system, as set forth in claim 1, wherein the pump is capable of pumping the flow material through the conduit at a plurality of flow rates.

8. The system, as set forth in claim 1, wherein the bubble-pumping device is adapted to deliver the bubble-forming material at a plurality of bubble flow rates and sizes.

9. The system, as set forth in claim 1, comprising:

a pulse dampener operatively coupled the conduit between the pump and the bubble-forming device.

10. The system, as set forth in claim 1, wherein the flow material comprises a surfactant.

11. A system for evaluating or calibrating a bubble detector, comprising:

a conduit adapted to pass a flow material therethrough, wherein the conduit is configured for passing flow materials of different viscosities;

a pump operatively coupled to the conduit to pump the flow material through the conduit;

a bubble-forming device operatively coupled to the conduit, the bubble-forming device being adapted to introduce bubbles into the flow material passing through the conduit; and

a bubble detector to be evaluated positioned to examine the bubbles in the flow material passing through the conduit,

wherein the bubble-forming device comprises;

a connecting device operatively coupled to the conduit;

a bubble-forming capillary adapted to be positioned within the connecting device in communication with the flow material passing through the conduit; and

a bubble-pumping device operatively coupled to the bubble-forming capillary, the bubble-pumping device adapted to deliver a bubble-forming material to the flow material in the conduit through the bubble-forming capillary to create bubbles in the flow material,

wherein the bubble-pumping device comprises a syringe.

12. A method of evaluating or calibrating a bubble detector comprising the acts of:

(a) pumping a flow material through a conduit, wherein the conduit is configured for passing flow materials of different viscosities;

(b) introducing bubbles into the flow material;

(c) examining the bubbles in the flow material with a bubble detector under evaluation; and

(d) detecting the bubbles in the flow material

wherein the act (b) comprises the act of;

using a capillary to inject bubbles into the flow material,

wherein the act of using a capillary comprises the act of;

slidably positioning the capillary within the flow material to adjust the size of the bubbles.

13. The method, as set forth in claim 12, wherein the act of using a capillary comprises the act of:

pumping a bubble-forming material through the capillary and into the flow material.

14. The method, as set forth in claim 12, wherein act (b) comprises the act of:

introducing a gas into the flow material to create the bubbles.

15. The method, as set forth in claim 12, comprising the act of:

mitigating pressure oscillations within the flow material.

16. The method, as set forth in claim 12, wherein act (c) comprises the act of:

using an ultrasonic probe to examine the bubbles in the flow material at a plurality of ultrasonic signal levels.

17. The method, as set forth in claim 12, wherein act (d) comprises the act of:

detecting the bubbles by visual inspection.

18. The method, as set forth in claim 12, wherein act (d) comprises the act of:

detecting the bubbles using a bubble detector having a known bubble detection resolution.

19. The method, as set forth in claim 12, comprising the act of:

comparing the examination of the bubbles in the flow material with the bubble detector with the detection of the bubbles in the flow material to calibrate the bubble detector.

20. The method of claim 19, comprising the acts of:

(a) calculating a calibration factor from the examination of the bubbles in the flow material with the bubble detector and the detection of the bubbles in the flow material; and

(b) applying the calibration factor to the bubble detector to calibrate the bubble detector.

21. The method, as set forth in claim 20, wherein act (b) comprises the act of:

programming the calibration factor into a memory of the bubble detector.

22. The method, as set forth in claim 12, wherein act (a) comprises the act of:

pumping the flow material in the conduit at a plurality of flow rates.

23. The method, as set forth in claim 12, wherein act (b) comprises the act of:

altering the size of the bubbles.

24. The method, as set forth in claim 12, wherein act (b) comprises the act of:

altering a formation rate of the bubbles.