Fluid flow control device
A flow control device having no moving parts that controls fluid flow along a fluid pathway in such a way that flow rate remains constant irregardless of environmental changes. The device achieves a constant flow rate by taking advantage of the properties of the fluid moving along the fluid pathway and maintains the constant flow rate irregardless of changes in viscosity due to changes in temperature.
1. A flow control device having a fluid pathway comprising a micro-channel having a first segment having an inner wall and being of a first radius, a second tapered segment having an inner wall, a third segment having an inner wall and second radius greater than said first radius, said inner wall of second tapered segment extending from said inner wall of said first segment toward said inner wall of said third segment at an acute angle and having an initial radius and a third radius substantially equal to said second radius of said third segment and means within said fluid pathway for achieving flow rate stabilization by providing viscosity dependent resistance to fluid flow along said fluid pathway, said means comprising a stationary vane protruding into said fluid pathway, said vane being constructed and arranged to produce an eddy within the fluid flowing along said micro-channel, said vane having a thickness of between about 5 μm and about 100 μm.
2. The device as defined in claim 1 in which said inner wall of second tapered segment extends from said inner wall of said first segment toward said inner wall of said third segment at an angle of between approximately 30 degrees and approximately 60 degrees.
3. The device as defined in claim 1 which said inner wall of second tapered segment extends from said inner wall of said first segment toward said inner wall of said third segment at an angle of approximately 30 degrees in which said vane is constructed and arranged to produce an eddy within the fluid flowing along said fluid pathway.
4. The device as defined in claim 1 which said inner wall of second tapered segment extends from said inner wall of said first segment toward said inner wall of said third segment at an angle of approximately 60 degrees.
5. The device as defined in claim 1 in which said vane extends from said wall at an angle of between about 15 degrees and about 75 degrees.
6. The device as defined in claim 1 in which said vane has a length of between about 25 μm and about 1,000 μm.
7. A flow rate stabilization device for stabilizing the rate of fluid flow through the device comprising:
(a) a housing having a fluid flow path comprising a micro-channel having a first segment having an inner wall and being of a first radius, a second tapered segment having an inner wall and a third segment having an inner wall and being of a second radius greater than said first radius, said second tapered segment having an initial radius and a third radius substantially equal to said second radius of said third segment, said inner wall of second tapered segment extending from said inner wall of said first segment toward said inner wall of said third segment at an angle of between about 30 degrees and about 60 degrees; and
(b) an obstacle connected to said housing and positioned within said micro-channel in a manner to generate an eddy that provides viscosity dependant resistance to the flow of fluid along said fluid flow path.
8. The device as defined in claim 7 in which said obstacle comprises a vane extending into said fluid flow path.
9. The device as defined in claim 7 in which said obstacle comprises a vane affixed to said wall and extending into said micro-channel.
10. The device as defined in claim 9 in which said vane extends from said wall at an angle of between about 15 degrees and about 75 degrees.
11. The device as defined in claim 10 in which said vane has a length of between about 25 μm and about 1,000 μm.
12. The device as defined in claim 11 in which said vane has a thickness of between about 5 μm and about 100 μm.
13. A fluid flow control device comprising:
(a) a housing having a fluid pathway comprising a micro-channel having a wall, a first segment having an inner wall and being of a first radius, a second tapered segment having an inner wall, a third segment having an inner wall and a second radius greater than said first radius, said second tapered segment having an initial radius of a magnitude intermediate between the magnitudes of said first radius of said first segment and said second radius of said third segment and a final radius substantially equal to said second radius of said third segment, said inner wall of second tapered segment extending from said inner wall of said first segment toward said inner wall of said third segment at an acute angle; and
(b) a plurality of stationary vanes affixed to said wall and extending into said micro-channel in a manner to create an eddy current within the fluid flowing along said fluid pathway.
14. The device as defined in claim 13 in which said inner wall of second tapered segment extends from said inner wall of said first segment toward said inner wall of said third segment at an angle of between about 30 degrees and about 60 degrees.
15. The device as defined in claim 13 in which said plurality of stationary vanes are randomly positioned.
16. The device as defined in claim 13 in which said vanes extend generally perpendicularly from said wall.
17. The device as defined in claim 13 in which said vanes have a length of between about 50 μm and about 200 μm.
18. The device as defined in claim 13 in which said vanes have a thickness of between about 5 μm and about 10 μm.
19. The device as defined in claim 13 in which said radius of said first segment is between about 80 μm and about 110 μm.
20. The device as defined in claim 19 in which said radius of said third segment is about 800 μm.