Fluid delivery system and sensing unit therefor
A fluid delivery system capable of delivering a precise amount of fluid, such as a fluid required for medical treatment. The delivery system makes use of an inline sensing unit that includes a housing comprising an inlet for receiving a fluid from a fluid source, an outlet for discharging the fluid from the housing, and at least one cavity between the inlet and the outlet. A sensing element and electronic circuitry are disposed within the at least one cavity. The electronic circuitry is adapted to produce an electrical output based on at least one response of the sensing element. The sensing unit is further equipped with a communication element for providing communication between the electronic circuitry and an electronic device remote from the housing.
1. An infusion system comprising:
an intravenous pole;
an intravenous tube hanging alongside the intravenous pole;
an inline sensing unit coupled to the intravenous tube and comprising a housing, an inlet for receiving a fluid from the intravenous tube, an outlet for discharging the fluid from the housing, at least one cavity between the inlet and the outlet, and a sensing element mounted within the at least one cavity, the sensing element having a first response to the density of the fluid flowing between the inlet and the outlet of the housing, the sensing element having a second response to the mass flow rate of the fluid flowing between the inlet and the outlet of the housing;
a module attached to the intravenous pole, the module comprising electronic circuitry that produces an electrical output based on at least one of the first and second responses of the sensing element, means for displaying a visual output based on the electrical output of the electronic circuitry, means for producing an audible output based on the electrical output of the electronic circuitry;
at least one of means for detecting gas bubbles within the fluid, means for detecting a phase within the fluid, and means for determining the fluid based on the density output of the electronic circuitry; and
means for providing communication between the sensing unit and the module;
wherein the sensing element comprises:
a freestanding tube portion through which the fluid flows;
means for vibrating the freestanding tube portion at a resonant frequency thereof that varies with the density of the fluid flowing therethrough, the resonant frequency of the freestanding tube portion being the first response of the sensing element, the Coriolis effect causing the freestanding tube portion to twist to a degree that varies with the mass flow rate of the fluid flowing therethrough while the freestanding tube portion is vibrated at resonance, the degree of twist being the second response of the sensing element; and
means for sensing movement of the freestanding tube portion to sense the resonant frequency and the degree of twist of the freestanding tube portion as the fluid flows therethrough.
2. The infusion system according to claim 1 , wherein the module does not contain components that contact the fluid, the sensing unit constitutes a separable disposable portion of the infusion system, and the module constitutes a reusable portion of the infusion system.
3. The infusion system according to claim 1 , further comprising means in communication with the module for stopping flow of the fluid through the intravenous tube in response to the electrical output of the electronic circuitry.
4. The infusion system according to claim 1 , further comprising a computer remote from the module and coupled to the module for communication therewith.