Fluid flow meter for gravity fed intravenous fluid delivery systems

• US 20030109836A1
• Filed: 12/07/2001
• Published: 06/12/2003
• Est. Priority Date: 12/07/2001
• Status: Active Grant

• Current Assignee: Medrip Limited
• Original Assignee: Medrip Limited
• Inventors: Shekalim, Avraham
• Granted Patent: US 6,679,865 B2
• Time in Patent Office: Days
• US Class Current: 604/251
• CPC Class Codes: A61M 2205/3379 Masses, volumes, levels of fluids in reservoirs, flow rates
• CPC Class Codes: A61M 5/16877 Adjusting flow; Devices for setting a flow rate
• CPC Class Codes: G01F 3/00 Measuring the volume flow of fluids or fluent solid material wherein the fluid passes through the meter in successive and more or less isolated quantities, the meter being driven by the flow measuring a proportion of the volume flow G01F5/00

Abstract

The present invention is a flow metering system for accurately metering and regulating the flow rate of fluid in a gravity fed intravenous fluid delivery system. The fluid flow is directed through a flow path guide that is suspended at an angle from one end. As the fluid flows through the flow path guide, the flow path guide bends due to the weight of the fluid. A drop of fluid forms at the end of the flow path guide then falls off, thereby releasing the flow path guide, which springs back it its original position. The sequence of drops and springing back continues throughout the fluid delivery procedure, and is monitored by sensors. The resultant data is used by a processor to determine the flow rate of the fluid. The flow rate may be adjusted as needed by a flow regulator that is responsive to an adjustment actuator that is controlled by the processor.

Claims

1. A flow meter for achieving an accurate reading of the flow rate of a fluid, the flow meter comprising:

(a) a fluid flow path guide along which the fluid flows, said flow path guide being deployed at an angle with an upper end fixedly attached to a meter inlet and a lower end suspended above a reservoir attached to a meter outlet, said flow path guide having an initial position, said flow path guide configured so as to have a given elastic resiliency such that when bent and subsequently released said flow path guide returns to said initial position;

(b) a sensing device configured and deployed so as to generate an output which varies as a function of movements of said flow path guide; and

(c) a processing unit in electronic communication with said sensing device, said processing unit configured to use said output from said sensing device to determine the flow rate.

2. The flow meter of claim 1, wherein said given elastic resiliency is inherent to the configuration of said flow path guide.

3. The flow meter of claim 1, wherein said flow path guide includes a conduit that is substantially closed along a dimension called length, said conduit being open to fluid flow at each of two ends.

4. The flow meter of claim 3, wherein said flow path guide includes a helical spring.

5. The flow meter of claim 1, wherein said given elastic resiliency is inherent to a material from which said flow path guide is fabricated.

6. The flow meter of claim 1, wherein said given elastic resiliency is inherent to a material from which an element, to which said flow path guide is attached, is fabricated.

7. The flow meter of claim 1, wherein said sensing device includes at least one magnetic sensor.

8. The flow meter of claim 1, wherein said sensing device includes an optical sensor.

9. The flow meter of claim 1, wherein at least one property that enables said sensing device to discern said movements of said flow path guide is inherent to a material from which said flow path guide is fabricated.

10. The flow meter of claim 1, wherein at least one property that enables said sensing device to discern said movements of said flow path guide is inherent to a material that is affixed to said flow path guide.

11. The flow meter of claim 1, wherein said flow path guide, said sensing device and said processor are housed in a single housing.

12. The flow meter of claim 1, wherein said flow path guide is deployed within a housing, said housing including said meter inlet and said meter outlet, and said sensing device and said processor are removably interconnected with said housing.

13. A flow metering system for accurately metering and regulating the flow rate of fluid flowing through a tube of a fluid delivery system, the flow metering system comprising:

(a) an adjustable flow regulator assembly having a regulator inlet, said flow regulator thereby receiving a flow of fluid, said flow regulator being configured so as to regulate the flow of fluid through said regulator, said regulator including an adjustment mechanism responsive to an adjustment actuator, said flow regulator further having a regulator outlet; and

(b) the flow meter of claim 1 in fluid communication with said regulator;

wherein said adjustment actuator is in electronic communication with, and responsive to, said processing unit, so as to regulate said flow.

14. The flow metering system of claim 13, wherein the fluid delivery system includes a gravity fed intravenous fluid delivery system for delivery of fluid drugs to a patient.

15. The flow metering system of claim 14, wherein said flow regulator assembly includes a variable length elongated flow path.

16. The flow metering system of claim 15, wherein said adjustment mechanism is configured so as to vary length of said elongated flow path.

17. The flow metering system of claim 13, wherein said processing unit, and said adjustment actuator are included in a base housing unit.

18. The flow metering system of claim 13, wherein at least part of said flow regulator and at least part of said flow meter are included in a removable fluid flow path unit.

19. A flow metering method for accurately metering the flow rate of fluid flowing through a tube of a fluid delivery system, the flow metering method comprising:

(a) directing the flow along a fluid flow path guide, said flow path guide being deployed at an angle with an upper end fixedly attached to a meter inlet and a lower end suspended above a reservoir attached to a meter outlet, said flow path guide having an initial position, said flow path guide configured so as to have a given elastic resiliency such that when bent and subsequently released said flow path guide returns to said initial position, said bending being caused by weight from a build up of fluid at a lower end and said return of said flow path guide to said initial position occurring when a drop is released from said lower end of said flow path guide;

(b) sensing movements of said flow path guide; and

(c) processing output resulting from said sensing, so as to derive fluid flow rate.

20. The flow metering method of claim 19, wherein the flow is regulated based on said processing.

21. The flow metering method of claim 20, wherein said regulating is accomplished by varying the length of a variable length elongated flow path.

22. The flow metering method of claim 21, wherein said varying is accomplished by activation of an adjustment actuator.

23. The flow metering method of claim 22, wherein said activation includes activation of an electric-motor-driven gear assembly.

24. The flow metering method of claim 20, wherein said regulation maintains a predetermined flow rate.

25. The flow metering method of claim 20, wherein said regulation changes the flow rate according to a predefined program.