Evaporator tube having an optimised external structure

Patent metadata

Field	Value
Publication number	US-9909819-B2
Application number	US-201715416752-A
Country	US
Kind code	B2
Filing date	Jan 26, 2017
Priority date	Dec 21, 2011
Publication date	Mar 6, 2018
Grant date	Mar 6, 2018

Abstract

A metal heat exchanger tube for the evaporation of liquids on the outside of the tube, having a tube axis, a tube wall, and integrally formed ribs that run circumferentially on the outside of the tube. The ribs have a rib foot, rib flanks, and a rib tip, wherein the rib foot projects substantially radially from the tube wall. A respective groove is located between every two ribs that are adjacent to one another in the axial direction. At least first, second, and third lateral material projections, which are formed from the material of the ribs, are arranged on a first, second, and third level on the rib flanks in such a way that the grooves are largely covered by all of the material projections. The first, second, and third lateral material projections are formed on levels that are in each case differently spaced apart from the tube wall in the radial direction.

First claim

What is claimed is:

1. A metal heat exchanger tube ( 1 ) for the evaporation of liquids on the outside ( 21 ) of the tube, comprising a tube axis, a tube wall ( 2 ), and integrally formed ribs ( 3 ), each of said ribs ( 3 ) running circumferentially in the form of a helical line on the outside ( 21 ) of the tube and having a rib foot ( 31 ), rib flanks ( 32 ), and a rib tip ( 33 ), wherein the rib foot ( 31 ) projects substantially radially from the tube wall ( 2 ), there is a respective groove ( 35 ) between every two ribs ( 3 ) that are adjacent to one another in the axial direction, and wherein lateral material projections formed from material of the ribs ( 3 ) are arranged on the rib flanks ( 32 ), wherein the maximum lateral extent of said material projections is less than the width W of the grooves, characterized in that at least first ( 41 ), second ( 42 ), and third ( 43 ) lateral material projections are arranged in such a way that the grooves ( 35 ) are largely covered by the material projections ( 41 , 42 , 43 ) taken as a whole, and that the first ( 41 ), second ( 42 ) and third ( 43 ) lateral material projections are formed on levels that are in each case differently spaced apart from the tube wall ( 2 ) in the radial direction.

2. The heat exchanger tube ( 1 ) as claimed in claim 1 , characterized in that the grooves ( 35 ) are covered to such an extent that the proportion of the groove bottom ( 36 ) that is visible is no more than 4% of the outer tube surface when viewed radially.

3. The heat exchanger tube ( 1 ) as claimed in claim 2 , characterized in that the grooves ( 35 ) are covered to such an extent that the proportion of the groove bottom ( 36 ) that is visible is no more than 2% of the outer tube surface when viewed radially.

4. The heat exchanger tube ( 1 ) as claimed in claim 3 , characterized in that the grooves ( 35 ) are covered to such an extent that the groove bottom ( 36 ) is not visible when viewed radially.

5. The heat exchanger tube ( 1 ) as claimed in claim 1 , characterized in that the lateral material projections ( 41 , 42 , 43 ) are of a discontinuous design in the circumferential direction of the tube on at least one level.

6. The heat exchanger tube ( 1 ) as claimed in claim 5 , characterized in that the lateral material projections ( 41 , 42 , 43 ) are of a discontinuous design in the circumferential direction of the tube on at least two levels, and the lateral material projections ( 41 , 42 , 43 ) on these levels are arranged at least partially offset relative to one another in the circumferential direction of the tube.

7. The heat exchanger tube ( 1 ) as claimed in claim 5 , characterized in that the grooves ( 35 ) are covered to such an extent that the groove bottom ( 36 ) is not visible or is visible only through openings with an area of at most 0.007 mm 2 when viewed radially.

8. The heat exchanger tube ( 1 ) as claimed in claim 1 , characterized in that the lateral extent of the material projections ( 41 , 42 , 43 ) is so great on at least one level that they overlap in the axial direction with the lateral material projections ( 41 , 42 , 43 ) which are formed on at least one other level on an opposite rib flank ( 32 ), and that the radial distance of these material projections ( 41 , 42 , 43 ) from the tube wall ( 2 ) is chosen in such a way that narrow passages remain between the material projections ( 41 , 42 , 43 ) in the region of overlap.

9. The heat exchanger tube ( 1 ) as claimed in claim 1 , wherein the ribs ( 3 ) are provided with notches ( 51 ) which extend in the direction of the rib foot ( 31 ) from the rib tip ( 33 ), wherein the depth of the notching is less than the height (H) of the ribs ( 3 ), on the level of the notches ( 51 ) material of the rib ( 3 ) forms first lateral material projections ( 41 ), which, on a first level, partially cover the groove ( 35 ) between two ribs ( 3 ) that are adjacent in the axial direction, there are second lateral material projections ( 42 ) between the rib tip ( 33 ) and the level of the notches ( 51 ), said projections partially covering, on a second level, the groove ( 35 ) between two ribs ( 3 ) that are adjacent in the axial direction, and the regions ( 54 ) of the rib tip ( 33 ) which are situated between two notches ( 51 ) that are adjacent in the circumferential direction of the tube are widened in the axial direction, with the result that the widened regions ( 54 ) of the rib tip ( 33 ) form third lateral material projections ( 43 ), which, on a third level, partially cover the groove ( 35 ) between two ribs ( 3 ) that are adjacent in the axial direction, characterized in that the grooves ( 35 ) between two ribs ( 3 ) that are adjacent in the axial direction are largely covered by the material projections ( 41 , 42 , 43 ) taken as a whole.

10. The heat exchanger tube ( 1 ) as claimed in claim 1 , wherein the maximum lateral extent of the material projections ( 41 , 42 , 43 ) is no more than 90% of the width W of the grooves.

Assignees

• Wieland Werke Ag

Inventors

• Lutz Ronald
• Beutler Andreas
• Schwitalla Andreas
• Revermann Markus
• Rettich Christian

Classifications

• F28F1/12 Primary

  the means being only outside the tubular element · CPC title

• F28D2021/0064

  Vaporizers, e.g. evaporators · CPC title

• F28F13/187 Primary

  especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites · CPC title

• F28F1/10

  Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses (crimped or corrugated elements F28F1/06, F28F1/08) · CPC title