Patent US5394732A successfully refreshed from Google Patents.
US5394732A
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US
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Method and apparatus for ultrasonic detection of air bubbles
Assignee: Gambro Renal Products Inc
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Filing: 1993-09-10
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Granted: 1995-03-07
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Expires: 2013-09-10
Abstract
Abstract Inclusions in a liquid flow, such as air bubbles in a blood flow, are detected by transmitting a signal through the fluid and receiving and interpreting the received signal based on the expected degree of attenuation for the liquid and the inclusions. The amplitude of the transmitted signal is automatically adjusted to maintain a constant average amplitude of the detected signal, thus compensating for changes in the detection environment. The average amplitude of the transmitted signal is controlled by integrating the received signal using an integrator with a time constant longer than the time constant of the expected inclusion signals, and comparing the integrated signal to a constant reference level. The presence of microbubbles is detected and a signal comprising a string of high frequency pulses is generated while the microbubbles are present. By counting the pulses, in conjunction with knowledge about the flow of liquid and the anticipated size of the microbubbles, an estimate of the total amount of air infused into the patient within a given time period is calculated. A tubing holder for retaining a flexible tube in an inclusion detector has tubing retention grooves formed into tubing engagement faces, the tubing engagement faces being spaced closer together than the tube diameter. The tube is inserted into the tubing holder by compressing and deforming it against the tubing engagement faces, until it reaches the tubing retaining grooves.
Inventors
- 👤 David A. Johnson
- 👤 Douglas P. Miller
- 👤 Keith J. Manica
- 👤 William M. Dormont
- 👤 Christopher J. Welsh
- 👤 William R. Mandel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 16:23
CPC Classifications
G; G01; G01N; G01N29/00; G01N29/44; G01N29/4409; G01N29/4427; A; A61; A61M; A61M1/00; A61M1/36; A61M1/3621; A61M1/3626; G01N29/02; G01N29/032; G01N29/22; G01N29/223; G01N29/32; G01N29/34; G01N29/36; G01N29/38; G01N2291/00; G01N2291/01; G01N2291/015; G01N2291/02; G01N2291/024; G01N2291/02433; G01N2291/02466; G01N2291/10; G01N2291/102
Claims Analysis
Total Claims: 50
Claim 1
Independent Claim
101 words
An inclusion detector for detecting the presence of inclusions in a flow of a liquid while compensating for changes in the detection environment comprising: a conduit; transmitting means for transmitting a signal through a liquid flowing in the conduit at a transmitted signal level; receiving means for receiving and interpreting the signal transmitted by the transmitting means, a change in a received signal level being indicative of the presence of an inclusion in the liquid flow; and signal adjusting means for adjusting the transmitted signal level to maintain an average value of the received signal level at a relatively constant value.
Claim 2
Dependent Claim
101 words
An inclusion detector for detecting the presence of inclusions in a flow of a liquid while compensating for changes in the detection environment comprising: a conduit; transmitting means for transmitting a signal through a liquid flowing in the conduit at a transmitted signal level; receiving means for receiving and interpreting the signal transmitted by the transmitting means, a change in a received signal level being indicative of the presence of an inclusion in the liquid flow; and signal adjusting means for adjusting the transmitted signal level to maintain an average value of the received signal level at a relatively constant value.
Claim 3
Dependent Claim
23 words
The inclusion detector defined in claim 1 wherein the inclusion is at least one bubble of at least one of air or gas.
Claim 4
Dependent Claim
21 words
The inclusion detector defined in claim 1 wherein the liquid is at least one of a biological or a pharmaceutical liquid.
Claim 5
Dependent Claim
18 words
The inclusion detector defined in claim 3 wherein the liquid is one of blood or a blood component.
Claim 6
Dependent Claim
14 words
The inclusion detector defined in claim 1 wherein the signal is an ultrasonic signal.
Claim 7
Dependent Claim
33 words
The inclusion detector defined in claim 5 wherein the conduit is flexible plastic medical tubing having a circumferential wall and the ultrasonic signals are transmitted and received through the wall of the tubing.
Claim 8
Dependent Claim
24 words
The inclusion detector defined in claim 5 wherein the transmitting means comprises: an oscillator; and a transmitting ultrasonic transducer electrically responsive to the oscillator.
Claim 9
Dependent Claim
29 words
The inclusion detector defined in claim 7 wherein the transmitting means further comprises a driver electrically responsive to the oscillator, the ultrasonic transducer being electrically responsive to the driver.
Claim 10
Dependent Claim
35 words
The inclusion detector defined in claim 8 wherein the adjusting means adjusts a level of voltage supplied to the driver to maintain a relatively constant voltage level at a predetermined point within the receiving means.
Claim 11
Dependent Claim
47 words
The inclusion detector defined in claim 9 wherein the driver comprises: a first transistor; and a second transistor; and the first and second transistors are electrically responsive to the oscillator to alternately apply and remove the voltage supplied to the driver to and from the transmitting transducer.
Claim 12
Dependent Claim
35 words
The inclusion detector defined in claim 7 wherein the receiving means comprises: a receiving ultrasonic transducer; a rectifier electrically responsive to the receiving transducer; and at least one signal comparator electrically responsive to the rectifier.
Claim 13
Dependent Claim
50 words
The inclusion detector defined in claim 11 wherein the receiving means further comprises: am amplifier electrically responsive to the receiving ultrasonic transducer, the rectifier being electrically responsive to the amplifier; and a filter electrically responsive to the rectifier, the at least one signal comparator being electrically responsive to the filter.
Claim 14
Dependent Claim
36 words
The inclusion detector defined in claim 12 wherein the level adjusting means adjusts the transmitted signal to maintain an average voltage level between the filter and the at least one comparator at a relatively constant value.
Claim 15
Dependent Claim
26 words
The inclusion detector defined in claim 11 further comprising: another signal comparator substantially identical to the at least one comparator and electrically responsive to the rectifier.
Claim 16
Dependent Claim
72 words
The inclusion detector defined in claim 11 wherein the at least one signal comparator comprises: a first signal comparator electrically responsive to the rectifier to detect the presence of a failure of the inclusion detector; a second signal comparator electrically responsive to the rectifier to detect the presence of a relatively large inclusion; and a third signal comparator electrically responsive to the rectifier to detect the presence of a relatively small inclusion.
Claim 17
Dependent Claim
32 words
The inclusion detector defined in claim 11 wherein the signal adjusting means further comprises: an integrator electrically responsive to the rectifier; and a supply voltage adjusting means electrically responsive to the integrator.
Claim 18
Dependent Claim
14 words
The inclusion detector defined in claim 1 wherein the inclusion is a solid particle.
Claim 19
Dependent Claim
14 words
The inclusion detector defined in claim 1 wherein the signal is a light signal.
Claim 20
Independent Claim
88 words
A method for detecting the presence of inclusions in a liquid flowing in a conduit while compensating for changes in the detection environment comprising: transmitting a signal through the liquid at a transmitted signal level; receiving the signal at a received signal level; interpreting the signal to detect the presence or absence of an inclusion, a sudden change in the received signal level being indicative of the presence of an inclusion; and adjusting the transmitted signal level to maintain the received signal level at a relatively constant level.
Claim 21
Independent Claim
88 words
A method for detecting the presence of inclusions in a liquid flowing in a conduit while compensating for changes in the detection environment comprising: transmitting a signal through the liquid at a transmitted signal level; receiving the signal at a received signal level; interpreting the signal to detect the presence or absence of an inclusion, a sudden change in the received signal level being indicative of the presence of an inclusion; and adjusting the transmitted signal level to maintain the received signal level at a relatively constant level.
Claim 22
Dependent Claim
23 words
The detecting method defined in claim 19 wherein the inclusion is at least one bubble of at least one of air or gas.
Claim 23
Dependent Claim
21 words
The detecting method defined in claim 19 wherein the liquid is at least one of a biological or a pharmaceutical liquid.
Claim 24
Dependent Claim
18 words
The detecting method defined in claim 21 wherein the liquid is one of blood or a blood component.
Claim 25
Dependent Claim
14 words
The detecting method defined in claim 19 wherein the signal is an ultrasonic signal.
Claim 26
Dependent Claim
33 words
The detecting method defined in claim 23 wherein the conduit is flexible plastic medical tubing having a circumferential wall and the ultrasonic signals are transmitted and received through the wall of the tubing.
Claim 27
Dependent Claim
32 words
The detecting method defined in claim 23 wherein the transmitting step comprises: generating an oscillating signal; and electrically driving a first ultrasonic transducer with the oscillating signal to produce ultrasonic mechanical vibrations.
Claim 28
Dependent Claim
31 words
The detecting method defined in claim 25 wherein the transmitting step further comprises amplifying the oscillating signal by a determined gain factor before the oscillating signal electrically drives the ultrasonic transducer.
Claim 29
Dependent Claim
38 words
The detecting method defined in claim 26 wherein the adjusting step comprises determining the determined gain of the amplifying step to maintain a relatively constant value of a voltage level that is proportional to the received signal level.
Claim 30
Dependent Claim
45 words
The detecting method defined in claim 25 wherein the receiving step comprises: mechanically driving a second ultrasonic transducer with the ultrasonic mechanical vibrations produced by the first ultrasonic transducer to produce an electrical signal; and rectifying the electrical signal to produce a rectified electrical signal.
Claim 31
Dependent Claim
33 words
The detecting method defined in claim 28 wherein the receiving step further comprises: amplifying the electrical signal before it is rectified; and filtering the rectified electrical signal to produce a filtered electrical signal.
Claim 32
Dependent Claim
42 words
The detecting method defined in claim 29 wherein the level adjusting step comprises adjusting the strength of the ultrasonic mechanical vibrations produced by the first ultrasonic transducer to maintain the average level of the filtered electrical signal at a relatively constant value.
Claim 33
Dependent Claim
51 words
The detecting method defined in claim 30 the signal adjusting step means further comprises: integrating the value of the filtered electrical signal to produce an integrated electrical signal; and adjusting the strength of the ultrasonic mechanical vibrations produced by the first ultra sonic transducer in response to the integrated electrical signal.
Claim 34
Dependent Claim
23 words
The detecting method of claim 29 wherein the interpreting step comprises comparing the filtered electrical signal to at least one predetermined reference signal.
Claim 35
Dependent Claim
54 words
The detecting method defined in claim 32 wherein the interpreting step further comprises: comparing the filtered electrical signal to a first predetermined reference signal to detect the presence of a relatively large inclusion; and comparing the filtered electrical signal to a second predetermined reference signal to detect the presence of a relatively small inclusion.
Claim 36
Dependent Claim
14 words
The detecting method defined in claim 19 wherein the signal is a light signal.
Claim 37
Dependent Claim
15 words
The detecting method detector defined in claim 19 wherein the inclusion is a solid particle.
Claim 38
Dependent Claim
99 words
An extracorporeal blood processing apparatus comprising: a conduit for conveying blood; transmitting means for transmitting an ultrasonic signal through the blood conveyed in the conduit at a transmitted signal level; receiving means for receiving and interpreting the ultrasonic signal transmitted by the transmitting means, a relatively sudden change in a received signal level being indicative of the presence of at least one bubble of at least one of air or gas in the blood; and signal adjusting means for adjusting the transmitted signal level to maintain an average value of the received signal level at a relatively constant value.
Claim 39
Dependent Claim
99 words
An extracorporeal blood processing apparatus comprising: a conduit for conveying blood; transmitting means for transmitting an ultrasonic signal through the blood conveyed in the conduit at a transmitted signal level; receiving means for receiving and interpreting the ultrasonic signal transmitted by the transmitting means, a relatively sudden change in a received signal level being indicative of the presence of at least one bubble of at least one of air or gas in the blood; and signal adjusting means for adjusting the transmitted signal level to maintain an average value of the received signal level at a relatively constant value.
Claim 40
Dependent Claim
11 words
The processing apparatus defined in claim 36 comprising a dialysis apparatus.
Claim 41
Dependent Claim
301 words
A tubing holder for retaining flexible tubing in contact with at least one ultrasonic transducer comprising: a first mounting block; a first generally planar tubing engagement face having an axis and a first leading edge generally parallel to the axis; a first tubing retaining groove recessed into the first tubing engagement face, the first tubing engagement groove being generally parallel to the axis and spaced a predetermined distance from the leading edge and having a generally arcuate cross sectional configuration; a first ultrasonic transducer mounted in the first mounting block below and in proximity with the first tubing retaining groove; a second mounting block; a second generally planar tubing engagement face having an axis and a second leading edge generally parallel to the axis; a second tubing retaining groove recessed into the second tubing engagement face, the second tubing engagement groove being generally parallel to the axis and spaced a predetermined distance from the leading edge and having a generally arcuate cross sectional configuration; and a housing securing and supporting the first and second mounting blocks in a relationship wherein: the first tubing engagement face faces the second tubing engagement face, is generally parallel to the second tubing engagement face and is spaced a predetermined distance from the second tubing engagement face; the first leading edge is generally parallel to and opposite the second leading edge; the first tubing retaining groove is generally parallel to and opposite the second tubing retaining groove; and the predetermined distance is selected to permit the tubing to be inserted between the first tubing engagement face and the second tubing engagement face at the location of the first and second leading edges when the tubing is relatively greatly compressed, and retained in the first and second tubing retaining grooves when the tubing is relatively less compressed.
Claim 42
Dependent Claim
301 words
A tubing holder for retaining flexible tubing in contact with at least one ultrasonic transducer comprising: a first mounting block; a first generally planar tubing engagement face having an axis and a first leading edge generally parallel to the axis; a first tubing retaining groove recessed into the first tubing engagement face, the first tubing engagement groove being generally parallel to the axis and spaced a predetermined distance from the leading edge and having a generally arcuate cross sectional configuration; a first ultrasonic transducer mounted in the first mounting block below and in proximity with the first tubing retaining groove; a second mounting block; a second generally planar tubing engagement face having an axis and a second leading edge generally parallel to the axis; a second tubing retaining groove recessed into the second tubing engagement face, the second tubing engagement groove being generally parallel to the axis and spaced a predetermined distance from the leading edge and having a generally arcuate cross sectional configuration; and a housing securing and supporting the first and second mounting blocks in a relationship wherein: the first tubing engagement face faces the second tubing engagement face, is generally parallel to the second tubing engagement face and is spaced a predetermined distance from the second tubing engagement face; the first leading edge is generally parallel to and opposite the second leading edge; the first tubing retaining groove is generally parallel to and opposite the second tubing retaining groove; and the predetermined distance is selected to permit the tubing to be inserted between the first tubing engagement face and the second tubing engagement face at the location of the first and second leading edges when the tubing is relatively greatly compressed, and retained in the first and second tubing retaining grooves when the tubing is relatively less compressed.
Claim 43
Dependent Claim
41 words
The tubing holder defined in claim 38 further comprising a second ultrasonic transducer mounted in the second mounting block below and in proximity with the second tubing retaining groove at a location generally opposite the location of the first ultrasonic transducer.
Claim 44
Dependent Claim
13 words
The tubing holder defined in claim 38 wherein the leading edges are beveled.
Claim 45
Independent Claim
182 words
A method for measuring the amount of air in the form of microbubbles in a liquid flowing in a tube comprising: transmitting a signal through the liquid at a transmitted signal level; receiving the signal at a received signal level; interpreting the signal to detect the presence or absence of a microbubble, a change in the received signal level being indicative of the presence of a microbubble; generating at least one logic signal pulse for each microbubble detected: counting the number of logic pulses generated over a predetermined time period; establishing the number of logic signal pulses that represent one microbubble and ascertaining the number of microbubbles in the tube during the predetermined time period; wherein: the logic pulses are generated at a predetermined frequency during a detection time period when a microbubble is detected; and the establishing step comprises: determining a value of a constant that is directly proportional to the frequency at which the logic pulses are generated and directly proportional to an expected microbubble size; and dividing the constant by a flow rate of the liquid in the tube.
Claim 46
Independent Claim
182 words
A method for measuring the amount of air in the form of microbubbles in a liquid flowing in a tube comprising: transmitting a signal through the liquid at a transmitted signal level; receiving the signal at a received signal level; interpreting the signal to detect the presence or absence of a microbubble, a change in the received signal level being indicative of the presence of a microbubble; generating at least one logic signal pulse for each microbubble detected: counting the number of logic pulses generated over a predetermined time period; establishing the number of logic signal pulses that represent one microbubble and ascertaining the number of microbubbles in the tube during the predetermined time period; wherein: the logic pulses are generated at a predetermined frequency during a detection time period when a microbubble is detected; and the establishing step comprises: determining a value of a constant that is directly proportional to the frequency at which the logic pulses are generated and directly proportional to an expected microbubble size; and dividing the constant by a flow rate of the liquid in the tube.
Claim 47
Dependent Claim
34 words
The method defined in claim 42 wherein the ascertaining step further comprises: dividing the number of logic pulses counted over the predetermined time period by the number of logic pulses that represent one microbubble.
Claim 48
Dependent Claim
33 words
The method defined in claim 41 further comprising: correlating the number of microbubbles ascertained in the predetermined time period with a volume of air in the flowing liquid during the predetermined time period.
Claim 49
Dependent Claim
29 words
The method defined in claim 41 further comprising: comparing the number of microbubbles ascertained in the predetermined time period with an allowable number of microbubbles for the time period.
Claim 50
Dependent Claim
32 words
The method defined in claim 41 further comprising: activating an alarm if the number of microbubbles ascertained in the predetermined time period exceeds the allowable number of microbubbles for the time period.
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