Optical flow sensor

• US 8,034,020 B2
• Filed: 06/19/2008
• Issued: 10/11/2011
• Est. Priority Date: 06/19/2008
• Status: Active Grant

• Current Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Original Assignee: Carefusion 303 Incorporated (Becton, Dickinson & Co)
• Inventors: Dewey, Paul
• Primary Examiner(s): Lucchesi; Nicholas D
• Assistant Examiner(s): FLICK, JASON E
• Application Number:
  US12/142,215
• Publication Number:
  US 20090318858A1
• Time in Patent Office: 1,209 Days
• Field of Search: 604/67
• US Class Current: 604/67
• CPC Class Codes: A61M 2205/3306 Optical measuring means
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 2205/368 by electromagnetic radiation, e.g. IR waves
• CPC Class Codes: A61M 5/16886 for measuring fluid flow rate, i.e. flowmeters
• CPC Class Codes: G01F 1/7044 using thermal tracers
• CPC Class Codes: G01F 1/7086 using optical detecting arrangements

Abstract

An optical flow sensor is provided, including a heater configured to heat an aliquot of fluid in an adjacent fluid-delivery channel and a sensor disposed adjacent to the fluid-delivery channel downstream from the heater. The sensor is configured to illuminate fluid in the fluid-delivery channel, to collect reflected light from the illuminated fluid, and to determine when the heated aliquot passes the sensor based upon an amount of the reflected light. A method for determining a flow rate of a fluid is also provided. The method includes heating an aliquot of the fluid at a first position of a fluid-delivery channel, illuminating fluid in the fluid-delivery channel at a second position downstream from the first position, measuring an amount of light reflected from the illuminated fluid to determine a change in the amount corresponding to the heated aliquot passing the second position, and calculating the flow rate of the fluid based upon a distance between the first position and the second position and a time between the heating the aliquot and the heated aliquot passing the second position.

Claims

1. An optical flow sensor, comprising:

a heater configured to heat an aliquot of fluid in an adjacent fluid-delivery channel; and

a sensor disposed adjacent to the fluid-delivery channel downstream from the heater, the sensor configured to illuminate fluid in the fluid-delivery channel, to collect reflected light from the illuminated fluid, and to determine when the heated aliquot passes the sensor based upon a change in an amount of the reflected light,

wherein the sensor comprises a light source positioned to emit light towards the fluid-delivery channel, and

wherein the light emitted from the light source does not refract before contact with the fluid-delivery channel.

2. The optical flow sensor according to claim 1, further comprising a processor configured to calculate a flow rate of the fluid in the fluid-delivery channel based upon a time between the heater heating the aliquot and the sensor determining when the heated aliquot passes the sensor.

3. The optical flow sensor according to claim 1, wherein the light source comprises a light emitting diode (LED) optically coupled to the fluid-delivery channel by a first fiber and a photodetector optically coupled to the fluid-delivery channel by a second fiber.

4. The optical flow sensor according to claim 3, wherein the first fiber and the second fiber are disposed on a same side of the fluid-delivery channel.

5. The optical flow sensor according to claim 3, wherein the LED and the photodetector are disposed on a same side of the fluid-delivery channel.

6. The optical flow sensor according to claim 1, wherein the heater is a laser.

7. The optical flow sensor according to claim 1, wherein the fluid is opaque.