Apparatus for fluid storage and delivery at a substantially constant pressure

• US 20050238512A1
• Filed: 08/19/2004
• Published: 10/27/2005
• Est. Priority Date: 04/26/2004
• Status: Active Grant

• Current Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Original Assignee: Georgia Tech Research Corporation (University System of Georgia)
• Inventors: Hesketh, Peter Julian, Luharuka, Rajesh, Wu, Chi-Fu
• Granted Patent: US 7,481,337 B2
• Time in Patent Office: Days
• US Class Current: 417/437
• CPC Class Codes: B33Y 80/00 Products made by additive manufacturing
• CPC Class Codes: F04B 19/006 Micropumps F04B43/043 and F04B43/095 take precedence
• CPC Class Codes: F04B 43/084 the tubular member being deformed by stretching or distortion
• CPC Class Codes: F04B 9/02 the means being mechanical

Abstract

Microfluidic pumps, methods of fabrication thereof, and methods of use thereof, as well as method of pumping a fluid, are disclosed.

Claims

1. A microfluidic pump, comprising:

a fluid reservoir system that includes a fluid chamber for holding a volume of a fluid;

an outlet structure having an outlet port, wherein the fluid reservoir system is fluidically coupled to the outlet port; and

a constant force system coupled to the fluid reservoir, wherein the constant force system is adapted to apply a force to the fluid chamber, wherein the force causes the volume of the fluid to flow out of the fluid chamber and through the outlet port at a substantially constant pressure.

2. The microfluidic pump of claim 1, wherein:

the constant force system includes a constant torque system rotationally coupled to the fluid reservoir system, wherein the constant torque system applies a torque on the fluid chamber to cause the volume of the fluid to flow out of the fluid chamber and through the outlet port at a substantially constant pressure.

3. The microfluidic pump of claim 2, wherein the constant torque system further comprises:

a torsion spring having a first end and a second end, the torsion spring fixed at the first end and coupled to the fluid reservoir system at the second end, wherein the torsion spring applies a torque on the fluid reservoir system causing the volume of the fluid to flow out of the fluid chamber and through the outlet port at a substantially constant pressure.

4. The microfluidic pump of claim 2, wherein the constant torque system further comprises:

an output drum connected to the fluid reservoir system; and

a constant torque device that applies a torque on the output drum, causing the volume of the fluid to flow out of the fluid chamber and through the outlet port at a substantially constant pressure.

5. The microfluidic pump of claim 4, wherein the constant torque system further comprises:

a take-up drum, wherein the output drum and the take-up drum are positioned about substantially parallel axes of rotation; and

the constant torque device is fastened to the output drum and the take-up drum, wherein the constant torque device applies a torque on the output drum and the take-up drum in opposite directions about their respective axes of rotation.

6. The microfluidic pump of claim 4, wherein the output drum comprises:

a rotatable pillar coupled to the fluid reservoir system such that the rotation of the output drum corresponds to the volume displaced from the fluid chamber through the outlet port.

7. The microfluidic pump of claim 6, wherein the rotatable pillar is disposed about a low friction system.

8. The microfluidic pump of claim 7, wherein the low fiction system is selected from a ball bearing, a bush bearing, a sleeve bearing, and combinations thereof.

9. The microfluidic pump of claim 7, wherein:

the rotatable pillar comprises a hollowed pillar;

the low fiction system is configured such that the rotatable pillar rotates about a cylidrical surface the low fiction system is configured such that the rotatable pillar rotates about a cylidrical surface; and

the cylidrical surface and at least the portion of the rotatable pillar contacting the cylindrical surface are coated with a low friction material, wherein the low fiction material is selected from;

polytetrafluoroethylene, lubricating oil, lubricating grease, and combinations thereof.

10. The microfluidic pump of claim 5, wherein the constant torque device comprises a constant torque spring.

11. The microfluidic pump of claim 5, wherein:

the output drum comprises a rotatable pillar coupled to the fluid reservoir system such that the rotation of the output drum corresponds to the volume displaced from the fluid reservoir system through the outlet port; and

the take-up drum comprises a rotatable pillar.

12. The microfluidic pump of claim 11, wherein:

the rotatable pillar is disposed about a first bearing; and

the take-up drum is disposed about a second bearing, wherein each of the first bearing and the second bearing are selected from;

a ball bearing, a bush bearing, a sleeve bearing, and combinations thereof.

13. The microfluidic pump of claim 11, wherein the rotatable pillars rotate about a low friction system.

14. The microfluidic pump of claim 13, wherein:

the rotatable pillars comprise hollowed pillars;

the rotatable pillars rotate about cylidrical surfaces; and

the cylidrical surfaces and at least the portion of the rotatable pillars contacting the cylindrical surfaces are coated with a low friction material wherein the low friction material is selected from;

polyfluoroethylene, lubricating oil, lubricating grease, and combinations thereof.

15. The microfluidic pump of claim 2, wherein the fluid reservoir system comprises:

a delivery structure rotationally coupled to the constant torque system; and

wherein the fluid chamber is a compressible fluid chamber, the compressible fluid chamber interposed between the delivery structure and the outlet port, wherein a torque applied to the delivery structure causes the delivery structure to compress the compressible fluid chamber, resulting in fluid being flowed through the outlet port at a pressure substantially constant over time.

16. The microfluidic pump of claim 15, wherein the compressible fluid chamber is chosen from:

a flexible bellows, a flexible bladder, a balloon, and combinations thereof.

17. A microfluidic pump comprising:

a fluid reservoir system including a curved fluid chamber and a curved delivery structure rotationally coupled to the torque system;

an outlet structure having an outlet port, the outlet port in fluidic communication with the fluid reservoir system; and

a constant torque system rotationally coupled to the torque system, wherein the torque system includes;

an output drum, the output drum rotationally coupled to the fluid reservoir system such that the rotation of the output drum actuates the delivery structure,

a take-up drum, and

a constant torque spring, the constant torque spring fastened to the output drum and take-up drum such that the constant torque spring applies a torque in substantially opposite directions about the respective axes of rotation of the output drum and the take-up drum and fastened such that the constant torque spring winds around the output drum and the take-up drum.

18. The microfluidic pump of claim 17, further comprising:

a base on which the fluid reservoir system is disposed, wherein the fluid reservoir system further comprises a delivery structure disposed adjacent the fluid reservoir system; and

wherein the constant torque system is coupled to the delivery structure, causing the delivery structure to displace a volume of fluid from the fluid chamber through the outlet port at a substantially constant pressure.

19. The microfluidic pump of claim 18, wherein the constant force system comprises:

a constant force spring having a first end and a second end, wherein each end of the constant force spring is coupled to the base, and wherein the constant force spring is disposed over the top of the fluid delivery structure.

20. The microfluid pump of claim 19, wherein the constant force spring is fastened to a first and a second bearing, the first and the second bearings disposed upon the base.

21. The microfluid pump of claim 19, wherein:

the constant force spring is fastened to a first and a second take-up drum disposed on the base.

22. The microfluid pump of claim 21, wherein:

the first and the second take-up drums comprise a rotatable pillar disposed about a low friction system.

23. The microfluid pump of claim 22, wherein:

the rotatable pillar comprises a hollowed pillar;

the rotatable pillar rotates about a cylidrical surface; and

the cylidrical surface and at least the portion of the rotatable pillar contacting the cylindrical surface are coated with a low friction material, wherein the low friction material is selected from;

polytetrafluoroethylene, lubricating oil, lubricating grease, a metal sleeve, and combinations thereof.

24. The microfluid pump of claim 21, wherein:

the first and the second take-up drums are each disposed about bearings, wherein the bearings are selected from;

a ball bearing, a bush bearing, a sleeve bearing, and combinations thereof.

25. The microfluidic pump of claim 18, wherein the constant torque system comprises:

a first constant force spring and a second constant force spring, wherein the first constant force spring and the second constant force spring each have a first end and a second end, wherein the first end of each constant force spring is coupled to the base, wherein the second end of each constant force spring is coupled to the delivery structure, and wherein the first constant force spring and second constant force spring apply a force substantially balanced about the center of the delivery structure.

26. The microfluid pump of claim 25, wherein the constant force springs are fastened to a first take-up drum and a second take-up drum disposed on the base.

27. The microfluid pump of claim 26, wherein the first and the second take-up drums each comprise a rotatable pillar disposed about a low friction system.

28. The microfluid pump of claim 27, wherein:

the rotatable pillar comprises a hollowed pillar; and

the low friction system is configured such that the rotatable pillar rotates about a cylidrical surface, and the cylidrical surface and at least the portion of the rotatable pillar contacting the cylindrical surface are coated with a low friction material, which is selected from;

polytetrafluoroethylene, lubricating oil, a metal sleeve, lubricating grease, and combinations thereof.

29. The microfluid pump of claim 26, wherein:

the first and the second take-up drums are each disposed about a first and a second bearing, wherein the first and the second bearings are selected from;

a ball bearing, a bush bearing, a sleeve bearing, and combinations thereof.

30. The microfluid pump of claim 25, wherein:

the first and the second constant force springs are fastened to a first bearing and a second bearing, the bearings disposed upon the base, and wherein the first bearing and the second bearing is selected from;

a ball bearing, a bush bearing, a sleeve bearing, and combinations thereof.

31. The microfluidic pump of claim 18, wherein the fluid chamber includes a compressible fluid chamber interposed between the fluid delivery structure and the outlet structure.

32. The microfluid pump of claim 31, wherein the compressible fluid chamber is chosen from:

a flexible bellows, a balloon, a flexible bladder, and combinations thereof.

33. A microfluidic pump comprising:

an outlet structure having an outlet port;

a fluid reservoir system in fluidic communication with the outlet port, wherein the fluid reservoir system comprises a hollowed channel, a fluid delivery structure disposed within the hollowed channel, and a compressible fluid chamber disposed within the hollow channel interposed between the fluid delivery structure and the outlet structure; and

a constant force system comprising a constant force spring fastened by each end to the base on substantially opposite sides of the base, and routed over the top of the fluid delivery structure between the fastening points.

34. A microfluidic pump comprising:

an outlet structure having an outlet port;

a fluid reservoir system disposed upon a base and in fluidic communication with the outlet port, wherein the fluid reservoir system comprises a hollowed channel, a fluid delivery structure disposed within the hollowed channel, and a compressible fluid chamber disposed within the hollow channel interposed between the fluid delivery structure and the outlet structure; and

a constant force system comprising a first constant force spring and a second constant force spring, each having a first end and a second end, the first constant force spring attached via the first end to a first take-up drum, the second constant force spring attached via the first end to a second take-up drum, the first take-up drum and the second take-up drum disposed about a low friction system on substantially opposite sides of the base, the first constant force spring attached via the second end to the fluid delivery structure, the second constant force spring attached via the second end to the fluid delivery structure on substantially the opposite side of the fluid delivery structure relative to the first constant force spring.

35. A microfluidic pump comprising:

an outlet structure having an outlet port;

a fluid reservoir system disposed upon a base and in fluidic communication with the outlet port, wherein the fluid reservoir system comprises a hollowed channel, a fluid delivery structure disposed within the hollowed channel, and a compressible fluid chamber disposed within the hollow channel interposed between the fluid delivery structure and the outlet structure; and

a constant force system comprising at least one constant force spring having a first end and a second end coupled to the fluid delivery structure via the first end and fastened to a low friction system disposed on the base via the second end, wherein the at least one constant force spring applies at least one force substantially balanced about the center of the fluid delivery structure.

36. A method of pumping fluid, comprising:

providing a fluid reservoir system coupled to an outlet structure having an outlet port, wherein the fluid reservoir system includes a fluid chamber having a volume of fluid;

providing a constant force system coupled to the fluid reservoir system; and

applying a constant force on the fluid chamber using the constant force system, wherein the constant force applied to a constant contact area of the piston causes the volume of the fluid to flow through the outlet port at a substantially constant pressure.

37. A method of pumping fluid, comprising:

providing a fluid reservoir system fluidically coupled to an outlet structure having an outlet port, wherein the fluid reservoir system includes a fluid chamber having a volume of fluid;

providing a constant torque system rotationally coupled to the fluid reservoir system; and

applying a constant torque on the volume of fluid using the constant torque system, wherein the constant torque applied to a constant contact area of the piston causes the volume of the fluid to flow through the outlet port at a substantially constant pressure.