METHOD FOR MAKING AND USING AN AIR BUBBLE DETECTOR

• US 20080098798A1
• Filed: 10/22/2007
• Published: 05/01/2008
• Est. Priority Date: 10/24/2006
• Status: Active Grant

• Current Assignee: Zevex (Moog Incorporated)
• Original Assignee: Zevex (Moog Incorporated)
• Inventors: Riley, Timothy, Crandall, Frank, Eggers, Philip, Stringham, Mark, Blaine, David
• Granted Patent: US 7,805,978 B2
• Time in Patent Office: Days
• US Class Current: 73/19.03
• CPC Class Codes: A61M 1/3626 Gas bubble detectors
• CPC Class Codes: A61M 2205/3375 Acoustical, e.g. ultrasonic, measuring means
• 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 2291/02854 Length, thickness
• CPC Class Codes: G01N 2291/048 Transmission, i.e. analysed material between transmitter and receiver
• CPC Class Codes: G01N 29/02 Analysing fluids using acoustic emission techniques G01N29/14 ; constructional or flow details for analysing fluids G01N29/222; optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/032 by measuring attenuation of acoustic waves
• CPC Class Codes: G01N 29/221 Arrangements for directing or focusing the acoustical waves electronic orientation or focusing G01N29/262; sound directing or focusing G10K11/26; mechanical steering of sound transducers or their beams G10K11/35
• CPC Class Codes: G01N 29/222 Constructional or flow details for analysing fluids optoacoustic fluid cells G01N29/2425
• CPC Class Codes: G01N 29/2468 Probes with delay lines
• CPC Class Codes: Y10T 29/42 Piezoelectric device making
• CPC Class Codes: Y10T 29/49005 Acoustic transducer
• CPC Class Codes: Y10T 29/4908 Acoustic transducer
• CPC Class Codes: Y10T 29/4979 Breaking through weakened portion
• CPC Class Codes: Y10T 29/49826 Assembling or joining

Abstract

A universal air bubble detector allows for use with a variety of sizes and types of tubing. The detector maintains proper alignment of a sensor emitter and receiver with different sizes of tubing. The detector may be mounted on existing equipment or may be used to monitor a tubing at any position along the tubing, and may operate in a stand alone mode or in combination with existing equipment.

Claims

1. A method for forming a universal bubble detector, the method comprising:

selecting an ultrasonic emitter;

selecting an ultrasonic receiver;

attaching the emitter and the receiver to a base having a first mount and a second mount movable relative to the first mount such that the ultrasonic emitter and ultrasonic receiver move relative to one another so as to vary the distance between the emitter and the receiver.

2. The method according to claim 1, wherein the method comprises moving the mounts so that the ultrasonic emitter and the ultrasonic receiver are disposed at a desired distance apart from one another and selectively locking the movable mount in place so that the ultrasonic emitter and the ultrasonic receiver may no longer move relative to one another.

3. The method according to claim 1, wherein the method comprises moving the mounts so that the ultrasonic emitter and the ultrasonic receiver are disposed at a desired distance apart from one another and permanently affixing the movable mount in place so that the ultrasonic emitter and the ultrasonic receiver may no longer move relative to one another.

4. The method according to claim 3, wherein the method comprises affixing the first mount in place using at least one of the group consisting of glue, solvent, and heat.

5. The method according to claim 1, wherein the method further comprises adjusting a height of at least one of the ultrasonic emitter and the ultrasonic receiver relative to the base.

6. The method according to claim 1, wherein the first mount and second mount define a channel therebetween and wherein the method comprises adjusting the depth of the channel in proportion to a distance between the ultrasonic emitter and the ultrasonic receiver.

7. The method according to claim 1, wherein the first and second mounts are arms and wherein the method comprises pivoting the emitter and the receiver relative to the arms to maintain the emitter and the receiver facing one another.

8. The method according to claim 1, wherein the method comprises automatically measuring the distance between the ultrasonic emitter and the ultrasonic receiver and automatically adjusting the operating conditions of the emitter and the receiver based on the measured distance.

9. The method according to claim 8, wherein the method comprises using a variable resistor to automatically measure the distance between the ultrasonic emitter and the ultrasonic receiver.

10. The method according to claim 8, wherein the method comprises using a change in distance between the emitter and receiver to determine a pressure change in a conduit passing between the emitter and receiver.

11. The method according to claim 1, wherein the method further comprises biasing the first mount toward the second mount.

12. The method according to claim 1, wherein at least one of the emitter and the receiver comprise a plurality of piezoelectric elements, and wherein the method further comprises selectively sending or receiving transmissions through the plurality of piezoelectric elements.

13. A method for detecting an undesired fluid in a fluid stream, the method comprising:

providing a transmitter for transmitting an ultrasonic signal through a conduit;

providing a receiver for receiving an ultrasonic signal through the conduit;

positioning the transmitter and the receiver so that the transmitter and the receiver are parallel to each other and such that the transmitter and receiver only partially overlap each other; and

processing signals received to detect the presence of the undesired fluid.

14. The method according to claim 13, wherein the fluid stream is a liquid and wherein the undesired fluid is a gas.

15. The method according to claim 13, wherein the fluid stream is gas and the undesired fluid is liquid.

16. A method for detecting air bubbles in a conduit, the method comprising:

selecting a piezoelectric transmitter and a piezoelectric receiver, at least one of the transmitter and the receiver comprising a plurality of piezoelectric elements and the other comprising a single piezoelectric element; and

transmitting a signal through a conduit containing a liquid from the transmitter to the receiver to thereby create a plurality of signals indicative whether an air bubble is in the liquid.

17. The method according to claim 16, wherein the receiver comprises a plurality of receiver elements and wherein the method comprises disposing the plurality of receiver elements in a curved array and generating signals indicative of ultrasonic signals received by the receiver elements.

18. The method according to claim 16, wherein the plurality of elements is disposed in a linear array along the conduit and wherein the method comprises determining the velocity at which the air bubble is moving through the conduit.

19. A method for detecting a foreign fluid in a conduit filled with a first fluid, the method comprising:

selecting an ultrasonic transmitter and an ultrasonic receiver;

positioning the transmitter along a conduit;

positioning the receiver along the conduit opposite the transmitter; and

forming a plurality of bubble detection areas along the conduit between the transmitter and the receiver.

20. The method according to claim 19, wherein the plurality of bubble detection areas are formed by at least one of the group consisting of:

selectively blocking the transmission of ultrasonic signals from the transmitter into the conduit and selectively blocking the receiver from receiving ultrasonic signals from the conduit.

21. The method according to claim 19, wherein the method comprises forming a plurality of pedestals between the at least one transmitter and the conduit to selectively transmit ultrasonic signals to from the transmitter to the conduit.

22. The method according to claim 21, wherein the method comprises disposing a masking compound between the plurality of pedestals to thereby block ultrasonic signals.

23. The method according to claim 19, wherein the method comprises forming a plurality of pedestals between the receiver and the conduit to selectively transmit ultrasonic signals to from the conduit to the at least one receiver.

24. A method for improving the detection of air bubbles in a conduit, the method comprising:

selecting a conduit having opposing sides;

disposing an ultrasonic transmitter on one side of the conduit;

disposing an ultrasonic receiver on a side of the conduit generally opposite from the transmitter; and

limiting the transmission area between the transmitter and the receiver to form a limited air bubble detection area in the conduit.

25. The method according to claim 24, wherein the method comprises masking at least one of the transmitter and the receiver to form a plurality of air bubble detection areas in the conduit between the at least one transmitter and the at least one receiver.

26. A method for forming a sensor comprising:

selecting a housing having a first electrical contact and a second electrical contact, the second electrical contact forming a spring; and

disposing an ultrasonic sensor element between the contacts so that the spring presses the ultrasonic the sensor element against the first electrical contact.