Device for reducing fouling in a tubular heat exchanger
The invention relates to a device for reducing fouling in a tube ( 1 ) through which a fluid passes. The inventive device comprises a mobile rotary element ( 3 ) and a fixed bearing-forming element ( 2 ) which can be solidly connected to the upstream end of the tube ( 1 ). In addition, the mobile element ( 3 ), which is connected to the fixed element ( 2 ), comprises an upstream trunnion-forming part ( 4 ) and a downstream turbulence-generating part ( 5 ) which is shaped such as to be rotated by the flow of the fluid in the tube ( 1 ). The aforementioned upstream ( 4 ) and downstream ( 5 ) parts are connected to one another by means of an elongated flexible connector ( 6 ) that is deformable along the entire length thereof.
1. A device for reducing fouling in a tube ( 1 ) through which a fluid passes, said device comprising;
a mobile rotary element ( 3 ); and
a fixed bearing-forming element ( 2 ) that is solidly connected to the upstream end of the tube ( 1 ),
wherein:
the mobile rotary element ( 3 ) is connected to the fixed bearing-forming element ( 2 ) and comprises an upstream trunnion-forming part ( 4 ) and a downstream turbulence-generating part ( 5 ), shaped so as to be rotated by the fluid flowing in the tube ( 1 ),
the upstream trunnion-forming part ( 4 ) and the downstream turbulence-generating part ( 5 ) are connected to one another by an elongate flexible connector ( 6 ) deformable along its whole length, fitted to permit damping of the dislodging force exerted by the mobile rotary element on the fixed bearing-forming element, and
wherein the downstream turbulence-generating part forms a separate and distinct element from the elongate flexible connector, with one end of the elongate flexible connector being connected to the downstream turbulence generating part.
2. The device as claimed in claim 1 , wherein the flexible connector ( 6 ) is a cable comprising braided or twisted strands, a chain or a ringed tube.
3. The device as claimed in claim 2 , wherein the flexible connector ( 6 ) is made from one of metal, plastic, carbon fibers, synthetic fibers, elastomer, and a composite material comprising a combination of a plurality of these materials.
4. The device as claimed in claim 2 , wherein the cable comprises a number of strands of 100 or less.
5. The device as claimed in any one of the preceding claims, wherein the length of the flexible connector ( 6 ) is between 1 cm and 5 cm.
6. The device as claimed in claim 1 , wherein the diameter of the flexible connector is between 2 and 10 mm.
7. The device as claimed in claim 1 , wherein the downstream turbulence-generating part ( 5 ) is helix shaped.
8. The device as claimed in claim 7 , wherein the ratio of the outside diameter of the helix to the inside diameter of the tube is between 0.5 and 0.9.
9. The device as claimed in claim 7 , wherein the outside diameter of the first turn or of the first turns of the helix is smaller than the outside diameter of the other turns of the helix.
10. The device as claimed in claim 9 , wherein the ratio of the outside diameter of the first turn, or of the first turns, to the inside diameter of the tube, is between 0.1 and 0.6.
11. The device as claimed in claim 1 , wherein the fixed bearing-forming element ( 2 ) is a cup-shaped yoke comprising a central part ( 7 ) drilled with an orifice for receiving the upstream trunnion-forming part ( 4 ) of the mobile rotary element ( 3 ), and two branches ( 8 ), symmetrical to one another, having a shape suitable for fixing them to the upstream end of the tube ( 1 ).
12. The device as claimed in claim 11 , wherein a first stop ( 9 ) is provided at the end of the upstream trunnion-forming part ( 4 ) and in that a second tubular stop ( 10 ) is provided on the central part ( 7 ) of the yoke in a prolongation of the orifice suitable for receiving the upstream trunnion-forming part of the mobile rotary element, forming therewith a channel for maintaining the upstream trunnion-forming part.
13. A heat exchanger comprising a plurality of tubes ( 1 ) through which a fluid passes, wherein a fouling reducing device as claimed in claim 1 , is fixed to the upstream end of at least one of said tubes.
14. The device as claimed in claim 3 , wherein the metal is stainless steel.
15. The device as claimed in claim 4 , wherein the number of strands is 50 or less.
16. The device as claimed in claim 5 , wherein the length of the flexible connector is between 2 cm and 4 cm.
17. The device as claimed in claim 6 , wherein the diameter of the flexible connector is between 4 and 8 mm.
18. The device as claimed in claim 8 , wherein the ratio of the outside diameter of the helix to the inside diameter of the tube is between 0.6 and 0.8.
19. The device as claimed in claim 10 , wherein the ratio of the outside diameter of the first turn, or of the first turns, to the inside diameter of the tube, is between 0.2 and 0.6.
20. The device as claimed in claim 1 , wherein the elongate flexible connector, the upstream trunnion-forming part and the downstream turbulence-generating part form three separate, distinct elements, with one end of the elongate flexible connector being connected to the upstream trunnion-forming part and a second end of the elongate flexible connector being connected to the downstream turbulence-generating part.