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CN-116507872-B - Metal heat exchanger tube

CN116507872BCN 116507872 BCN116507872 BCN 116507872BCN-116507872-B

Abstract

The invention relates to a metal heat exchanger tube (1) comprising integral fins (2) formed on the outside of the tube, having a fin bottom (3), fin flanks (4) and fin tips (5), wherein the fin bottom (3) protrudes radially from the tube wall (10) and channels (6) are formed between the fins (2), which channels have a channel base (61) and in which channels additional structures (7,71,72) are arranged spaced apart from one another. The additional structure (7,71,72) divides the channels (6) between the fins (2) into segments (8). The first additional structure (7, 71) is a protrusion (71) starting from the channel base (61) and pointing radially outwards. A radially outwardly located material protrusion (72) is arranged as a second additional structure (7,72) at the location of the protrusion (71). The heat exchanger tube of the present invention has improved properties of evaporating liquid on the outside of the tube.

Inventors

  • Achim Gotbam
  • Manfred Naboo
  • RONALD LUTZ

Assignees

  • 威兰德-沃克公开股份有限公司

Dates

Publication Date
20260505
Application Date
20211007
Priority Date
20201031

Claims (9)

  1. 1. A metal heat exchanger tube (1) for evaporating a liquid fluid on the outer surface of the tube, comprising integral fins (2) formed on the outside of the tube and having a fin bottom (3), fin flanks (4) and fin tips (5), wherein the fin bottom (3) protrudes radially from the tube wall (10) and channels (6) with channel bases (61) are formed between the fins (2), wherein channel-spaced additional structures (7) are arranged in the channels, -The additional structure divides the channels (6) between the fins (2) into segments (8), and -Said additional structure locally reduces the through-flow cross-sectional area in the channel (6) between the two fins (2), thus restricting at least the fluid flow in the channel (6) during operation, and Wherein the first additional structure is radially outwardly directed protrusions (71) emerging from the channel base (61) and each being delimited in the radial direction by an end surface (713) located between the channel base (61) and the fin tips (5), as a result of which the radial extent of the protrusions (71) is defined, Material projections (72) in the form of a second additional structure are arranged radially outwards at the location of the projections (71), which are formed from the material of the fin flanks (4), -The material projections (72) are each arranged in radial direction between the end surface (713) and the fin tips (5) and in contact with the end surface (713) of the projection (71) such that the material projections (72) are formed transversely on the fin flanks (4) via the channel base (61) of the channel (6) around the radial extent of the projection (71), and Wherein the material projection (72) extends further in the axial and radial direction than in the circumferential direction, -Wherein the protrusions (71) and the material protrusions (72) locally reduce the through-flow cross-sectional area in the channel (6) between two fins (2) by at least 30%, thereby controlling the exchange of fluid between adjacent segments (8).
  2. 2. Heat exchanger tube (1) according to claim 1, characterized in that the protrusions (71) and material protrusions (72) locally reduce the through-flow cross-sectional area in the channel (6) between two fins (2) by 40% to 70%.
  3. 3. Heat exchanger tube (1) according to claim 1 or 2, characterized in that the channels (6) are closed radially outwards except for a separate partial opening (9).
  4. 4. A heat exchanger tube (1) according to claim 1, wherein each segment (8) has at least one partial opening (9).
  5. 5. A heat exchanger tube (1) according to claim 1, wherein the protrusions (71) are formed at least of the material of the channel base (61) between two integrally encircling fins (2).
  6. 6. A heat exchanger tube (1) according to claim 5, wherein the protrusion (71) has a height between 0.15 mm and 1 mm.
  7. 7. A heat exchanger tube (1) according to claim 1, wherein the protrusions (71) have an asymmetric shape.
  8. 8. A heat exchanger tube (1) according to claim 1, wherein the protrusion (71) has a trapezoidal cross-section in a cross-sectional plane extending perpendicular to the tube longitudinal axis (a).
  9. 9. A heat exchanger tube (1) according to claim 1, characterized in that opposing material projections (72) are formed at the location of the projections (71) in the direction of the tube longitudinal axis (a).

Description

Metal heat exchanger tube Technical Field The present invention relates to metal heat exchanger tubes. Background Evaporation occurs in many sectors of refrigeration and air conditioning engineering and in process and power engineering. Tubular heat exchangers are often used, in which the liquid evaporates from a pure substance or mixture on the outside of the tube and in the process cools the brine or water on the inside of the tube. By making the heat transfer on the outside and inside of the tube more intense, the size of the evaporator can be greatly reduced. In this way, the production costs of such a device are reduced. Furthermore, the amount of refrigerant required is reduced, which is important in view of the fact that the mainly used chlorine-free safety refrigerant can at the same time form a non-negligible part of the total equipment costs. Furthermore, conventional high power tubes today have been about four times more efficient than smooth tubes with the same diameter. The highest performance commercially available finned tubes for flooded evaporators have fin structures on the outside of the tube with fin densities of 55 to 60 fins/inch (U.S. Pat. No. 5,669,441A; U.S. Pat. No. 5,697,430A; DE 197 57 526 C1). This corresponds to a fin spacing of about 0.45mm to 0.40 mm. Furthermore, it is known that by introducing additional structural elements in the region of the groove bottoms between the fins, it is possible to produce evaporation structures with improved performance, wherein the fin spacing remains the same on the outside of the tubes. In EP 1,223,400 B1, it is proposed to create undercut secondary grooves on the groove bottoms between the fins, said secondary grooves extending continuously along the primary grooves. The cross-section of the secondary grooves may remain constant or may vary at regular intervals. Other examples of structures on the bottom of the groove can be found in EP 0 222 100 B1, US 7,254,964 B2 or US 5,186,252A. A common feature of the structures is that the structural elements do not have an undercut shape on the groove bottom. These are indentations introduced into the bottom of the groove, or protrusions in the lower region of the channel. In the prior art, higher protrusions are clearly excluded, as it seems that the fluid flow in the channels is disadvantageously blocked for heat exchange. Another method with a higher structure emerging from the groove bottom is disclosed in EP 3 111 153 B1. These structures are protrusions in the channels that result in the segmentation. By the segmentation between the two fins, the channels are repeatedly interrupted in the peripheral direction, thus at least reducing or completely preventing migration of heat exchange fluid and emerging bubbles in the channels. The exchange of liquid and vapor along the channels is less and less, or even no longer assisted by the corresponding additional structures. Disclosure of Invention The present invention is based on the object of developing a heat exchanger tube with improved properties for evaporating a liquid on the outside of the tube. The invention includes a metal heat exchanger tube comprising integral fins formed on the outside of the tube having fin bases, fin flanks and fin tips, wherein the fin bases project radially from the tube wall and channels having channel bases are formed between the fins, wherein additional structures of channel spacing are disposed in the channels. The additional structure divides the channels between the fins into segments. The additional structure locally reduces the through-flow cross-sectional area in the channel between the two fins and thereby at least restricts the fluid flow in the channel during operation. The first additional structure is a radially outwardly directed projection emerging from the channel base and each being delimited in a radial direction by an end surface located between the channel base and the fin tips, as a result of which the radial extent of the projection is defined. The material projections in the form of the second additional structure are arranged radially outwardly at the location of the projections, the material projections being formed by the material of the flanks of the fins. The material projections are each arranged between the end surface and the fin tips in a radial direction such that the material projections are formed laterally on the fin flanks via the channel base of the channel, around the radial extent of the projections. The material projections extend further in the axial and radial directions than in the circumferential direction. These metal heat exchanger tubes are particularly useful for evaporating liquids from pure substances or mixtures on the outside of the tubes. This type of high efficiency tube can be manufactured by means of a rolling disc based on integrally rolled finned tubes. Integrally rolled finned tubes are understood to mean finned tubes in which the fins have been formed from