Air bubble sensor
First Claim
1. A system for automatically detecting a gas bubble in a liquid flowing through a tube of an intravenous line having a cassette disposed therein, comprising:
- (a) a chassis;
(b) a transmitter for generating an acoustic signal that is directed through a portion of the tube, the transmitter being disposed at one side of the tube, in contact therewith;
(c) a receiver for receiving the acoustic signal and producing an electrical signal in response thereto, the receiver being in contact with an opposite side of the tube, directly opposite the transmitter; and
(d) a pair of members, each member of the pair being pivotally coupled to and supported by the chassis, one member supporting the transmitter, another member supporting the receiver, the pair of members being pivoted in an outwardly direction in response to engagement between the cassette and the pair of members, said members being pivoted in an inwardly direction to position the transmitter and the receiver in contact with the opposite sides of the tube, a magnitude of the electrical signal produced by the receiver indicating whether a gas bubble is disposed in the tube between the receiver and the transmitter.
3 Assignments
0 Petitions
Accused Products
Abstract
A system and a method for detecting the presence of air bubbles in an intravenous (IV) line supplying a medicinal liquid to a patient. An air bubble sensor includes an ultrasonic transmitter acoustically coupled to an ultrasonic receiver to detect the presence of a gas (e.g., air) in a portion of a tube comprising the IV line. The transmitter and receiver are mounted on pivoting transducers that are disposed on opposite sides of the tube. A spring biases the transducers inwardly toward each other so that the transmitter and receiver contact opposite sides of the tubing. This assembly automatically accommodates different sizes of tubing and tubing of a relatively wide range of stiffness. The tube is connected to a disposable pumping cassette that is engaged in a pump chassis on which the transducers are pivotally mounted. A user actuated plunger on the pump chassis is depressed to cause the transmitter and receiver to move away from the tube when the pumping cassette is removed from or inserted into the interior of the pump chassis. A controller precisely monitors the flow of medicinal liquid through the tubing to detect the size of gas bubbles and total volume of gas infused. The controller automatically compensates for minor contamination of the exterior surface of the tube, e.g., if the surface is wet with a liquid.
174 Citations
35 Claims
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1. A system for automatically detecting a gas bubble in a liquid flowing through a tube of an intravenous line having a cassette disposed therein, comprising:
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(a) a chassis; (b) a transmitter for generating an acoustic signal that is directed through a portion of the tube, the transmitter being disposed at one side of the tube, in contact therewith; (c) a receiver for receiving the acoustic signal and producing an electrical signal in response thereto, the receiver being in contact with an opposite side of the tube, directly opposite the transmitter; and (d) a pair of members, each member of the pair being pivotally coupled to and supported by the chassis, one member supporting the transmitter, another member supporting the receiver, the pair of members being pivoted in an outwardly direction in response to engagement between the cassette and the pair of members, said members being pivoted in an inwardly direction to position the transmitter and the receiver in contact with the opposite sides of the tube, a magnitude of the electrical signal produced by the receiver indicating whether a gas bubble is disposed in the tube between the receiver and the transmitter. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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19. A system for automatically detecting a gas bubble in a liquid flowing through a tube of an intravenous line, comprising:
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(a) a chassis, said chassis defining a slot that is substantially wider than a diameter of the tube; (b) an ultrasonic transmitter that produces an ultrasonic signal directed through a portion of the tube disposed within the slot, the ultrasonic transmitter being disposed adjacent a side of the portion of the tube; (c) an ultrasonic receiver for receiving the ultrasonic signal and producing a corresponding electrical signal, the receiver being disposed on an opposite side of the portion of the tube, directly opposite the ultrasonic transmitter; (d) a pair of members pivotally connected to the chassis and disposed adjacent opposite sides of the slot, one member having an end facing toward the slot, said ultrasonic transmitter being disposed on said end, another member also having an end facing toward the slot, said ultrasonic receiver being disposed thereon, the pair of members pivoting to position the ultrasonic transmitter and the ultrasonic receiver against the sides of the portion of the tube and as a result, accommodating tubes of different external diameters and different stiffnesses; and (e) a controller that is coupled to the ultrasonic transmitter to excite the ultrasonic transmitter at a resonant frequency, so that the ultrasonic transmitter produces the ultrasonic signal, and to the ultrasonic receiver to receive the electrical signal produced thereby in response to the ultrasonic signal, the controller responding to a magnitude of the electrical signal to determine whether a liquid or a gas is in the portion of the tube disposed between the ultrasonic receiver and the ultrasonic transmitter.
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20. A method for detecting a gas bubble in a liquid that flows through a tube of an intravenous line and automatically accommodating tubes of different stiffness, comprising the steps of:
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(a) providing a chassis; (b) providing a pair of members, each member of the pair pivotably mounted and supported by said chassis, said members pivotable in an outwardly direction in response to engagement between the cassette and the pair of members; (c) mounting a receiver and a transmitter to said members respectively to position said receiver and transmitter on opposing sides of a portion of the tube; (d) exciting the transmitter to produce an acoustic signal that is acoustically coupled to the receiver through said portion of the tube, and the receiver producing an electric signal that corresponds to an acoustic signal received from the transmitter, a magnitude of said electrical signal being indicative that one of the gas and the liquid is disposed in the portion of the tube; (e) periodically sampling the electrical signal produced by the receiver to monitor flow through the tube, detecting said one of the gas and the liquid in the portion of the tube; (f) applying a biasing force to pivot the members in an inwardly direction to cause said transmitter and receiver into contact with the portion of the tube, so that tubes having different stiffness are automatically accommodated with sampling the electrical signal. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35)
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Specification