Ultrasonic air-in-line detector for a medication infusion system
First Claim
1. A system for detecting the presence of a significant amount of air in fluid passing through a fluid passageway, comprising:
- ultrasonic sensor means disposed adjacent said fluid passageway for providing an air-in-line output signal indicative of whether there is presently air or fluid in said fluid passageway at the location monitored by said ultrasonic sensor means;
means for monitoring the volume pumped through said fluid passageway, said monitoring means providing a volume output signal indicative of the volume pumped;
means, responsive to said air-in-line output signal and said volume output signal, for calculating the volume of air contained in the last predetermined volume pumped through said fluid passageway, said calculating means providing as an output the volume of air contained in the last predetermined volume pumped; and
means for providing an alarm signal if the output from said calculating means is equal to or greater than a second predetermined volume.
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Accused Products
Abstract
An ultrasonic air-in-line detection system for use in detecting air bubbles in the fluid line of a disposable cassette mounted on a main pump unit is disclosed which can accurately detect air bubbles in any type of fluid, whether clear or opaque. The system uses a windowing technique to determine when a threshold amount of air bubbles in a predetermined volume of material pumped occurs, with the alarm being sounded only when this threshold amount of air bubbles is present in the window volume. The system of the present invention thus avoids so-called nuisance alarms due to the presence of small isolated air bubbles in the fluid due to the fluid pumped not having been degassed.
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Citations
20 Claims
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1. A system for detecting the presence of a significant amount of air in fluid passing through a fluid passageway, comprising:
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ultrasonic sensor means disposed adjacent said fluid passageway for providing an air-in-line output signal indicative of whether there is presently air or fluid in said fluid passageway at the location monitored by said ultrasonic sensor means; means for monitoring the volume pumped through said fluid passageway, said monitoring means providing a volume output signal indicative of the volume pumped; means, responsive to said air-in-line output signal and said volume output signal, for calculating the volume of air contained in the last predetermined volume pumped through said fluid passageway, said calculating means providing as an output the volume of air contained in the last predetermined volume pumped; and means for providing an alarm signal if the output from said calculating means is equal to or greater than a second predetermined volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17)
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18. A system for detecting the presence of a significant amount of air in fluid passing through a fluid passageway, comprising:
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a first ultrasonic transducer located on one side of said fluid passageway; a second ultrasonic transducer located on the other side of said fluid passageway; means for driving said first ultrasonic transducer to generate ultrasonic vibrations which are transmitted to said one side of said fluid passageway, said ultrasonic vibrations passing through said fluid passageway and being received by said second ultrasonic transducer when there is fluid in said fluid passageway, said ultrasonic vibrations substantially not passing through said fluid passageway and not being received by said second ultrasonic transducer when there is an air bubble in said fluid passageway; receiver means for detecting the ultrasonic vibrations received by said second transducer and providing an air-in-line output signal indicative of whether there is presently air or fluid in said fluid passageway between said first and second transducers; means for monitoring the volume pumped through said fluid passageway, said monitoring means providing a volume output signal indicative of the volume pumped; means, responsive to said air-in-line output signal and said volume output signal, for calculating the volume of air contained in the last predetermined volume pumped through said fluid passageway, said calculating means providing as an output the volume of air contained in the last predetermined volume pumped; and means for providing an alarm signal if the output from said calculating means is equal to or greater than a second predetermined volume.
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19. A system for detecting the presence of a significant amount of air in fluid passing through a fluid passageway, comprising:
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sensor means disposed adjacent said fluid passageway for providing an air-in-line output signal indicative of whether there is presently air or fluid in said fluid passageway at the location monitored by said sensor means; means for monitoring the volume pumped through said fluid passageway, said monitoring means providing a volume output signal indicative of the volume pumped; means, responsive to said air-in-line output signal and said volume output signal, for calculating the volume of air contained in the last predetermined volume pumped through said fluid passageway, said calculating means providing as an output the volume of air contained in the last predetermined volume pumped; and means for providing an alarm signal if the output from said calculating means is equal to or greater than a second predetermined volume.
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20. A method of detecting the presence of a significant amount of air in fluid passing through a fluid passageway, comprising:
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providing an air-in-line output signal indicative of whether there is presently air or fluid in said fluid passageway at a particular location with an ultrasonic sensor means disposed adjacent said fluid passageway at said particular location; monitoring the volume pumped through said fluid passageway and providing a volume output signal indicative of the volume pumped; calculating, from said air-in-line output signal and said volume output signal, the volume of air contained in the last predetermined volume pumped through said fluid passageway and providing as an output the volume of air contained in the last predetermined volume pumped; and providing an alarm signal if the output from said calculating means is equal to or greater than a second predetermined volume.
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Specification