JP5399472B2 - Finned tubes for condensation and evaporation - Google Patents

Description

  The present invention relates to a finned tube for heat transfer such as a tube used in a shell and a heat exchanger.

  Finned tubes have been used for heat transfer for many years. Heat moves from the hot position to the cold position. Thus, heat transfer is achieved by transferring heat from a warmer material to a cooler material. Also, heat is released when the gas liquefies from vapor to liquid, and heat is absorbed when the liquid volatilizes or evaporates from liquid to vapor. When finned tubes are used for heat transfer, warmer materials are placed either inside or outside the tube, and cooler materials are placed on the opposite side. Typically, the tube achieves heat transfer without mixing warmer and colder materials.

  For the purpose of cooling, the cooling medium is a liquid such as cooling water that flows through the shell and tube heat exchanger, or a gas such as air that blows through the finned tube. Similarly, the heat medium is typically either a liquid or a gas. Finned tubes may be used instead of associated smooth tubes because of their high heat transfer rates. As a result, in a given application, a smaller heat exchanger with finned tubes can transfer as much heat as a larger heat exchanger with an associated smooth tube. The design of the finned tube affects the heat transfer rate. The tube may be designed for each specific heat transfer application. For example, a finned tube for condensation is designed to be different from a finned tube for evaporation.

  Examples of the prior art include a finned tube with a helical ridge formed on the inner surface of the tube and a fin formed on the outer surface of the tube. Adjacent fins on the outer surface of the tube define a channel, which has a curved “U” shaped bottom or a flat bottom. If the tube is used as a condensing tube that utilizes vapor condensation outside the tube and cooling fluid flowing inside the tube, the channel is filled with condensate. The condensate serves to protect the tube and limit the cooling required for additional condensation. The condensate tends to spread along the bottom of the flat channel rather than ascending the sides of the fin. For this reason, a flat bottom is preferred. Thereby, since the surface area in the fin through which a condensate flows freely becomes larger, heat transfer efficiency improves.

  Further, in the finned tube, a crack is formed in the fin. This causes the condensate flowing in the channel between the two fins to flow through the crack and enter a different channel. Another finned tube has a fin that is partially bent on the outside so that a bend is formed in a portion of the passage between the fin base and the fin upper end. This makes it possible to form fins with additional angles that allow the tube to eject the condensate more quickly. The heat transfer efficiency improves when the condensate is ejected from the tube more quickly. The other fin has a notch formed at the tip of the fin and includes a tip defined between the notches. In some examples, the tip is bent into a curved shape. This further increases the curvature and the angle of the fins, thus allowing the tube to eject the condensate more quickly.

  Some finned tubes are formed by attaching a fin material to an associated smooth tube so that the fins are not formed from the material of the tube body. This increases the area available for heat transfer so as to improve heat transfer efficiency, but the joint between the fin and the tube provides some resistance to heat transfer. Fins attached to the tube can extend radially from the tube axis to stand upright from the tube. However, to improve heat transfer efficiency, they may be curved or bent by various methods.

  Some tubes are designed for evaporation on the outer surface of the tube. For example, the fin is formed on the outer surface of the tube and the score is pushed into the upper end of the fin. The fin is then bent so that the fin upper end contacts the adjacent fin so that the bent fin forms a roof that covers the channel between two adjacent fins. This forms a cavity that is largely enclosed between the outer surface of the tube and two adjacent fins. A notch in the upper end of the fin allows liquid to flow into the cavity and vapor to be released from the cavity. Although there are many designs in existing finned tubes, further changes are possible that improve heat transfer efficiency.

  The heat transfer tube has adjacent fins extending from the outer surface of the tube, with channels between the fins. The fins are formed from a material on the outer surface of the tube so as to be integral with the tube body. The vanes extend from opposing fin sidewalls between the fin base and the fin upper end to form a barrier that divides the channel into an upper channel and a lower channel. A plurality of holes through the barrier are formed. The blade includes an upper blade and a lower blade. The tube includes a spiral ridge formed on the inner surface of the tube and a recess formed at the upper end of the fin.

FIG. 1 is a perspective view showing a cross section of a finned tube. FIG. 2 is a side sectional view showing the finned tube. FIG. 3 is a top view showing the outer surface of the tube including a cut-out cross section showing the outer surface of the tube at the bottom surface of the blade. FIG. 4 is a perspective view showing a cross section of a finned tube having a recess at the upper end of the fin. FIG. 5 is an enlarged perspective view showing a cross section of one fin. FIG. 6 is a side view of the arbor and the internal support, including a cross-section of the tube sidewall between the arbor and the internal support.

The finned tube of the present invention is intended to be used for heat transfer and primarily phase change on the outer surface of the tube. Typically, heat transfer tubes are designed for either evaporation (boiling) or condensation, but not both. The present invention includes desirable structures for evaporation and condensation. For this reason, the tube is efficiently used for both types of phase changes. The tube is designed to promote a phase change at the outer surface of the tube using a heat or cooling medium such as a liquid flowing in the tube. Tubes are often utilized in shell and tube heat exchanger configurations. However, other applications are possible.
Heat transfer principle

  To facilitate the following explanation, heat transfer during condensation is described. The same basic principle can be applied to evaporation, except that the direction of heat transfer is reversed. In this example, the coolant flowing through the tube absorbs the heat of condensation as the vapor liquefies on the outer surface of the tube. The fin design on the outer surface of the tube can increase the surface area of the tube and improve the ability of the tube to eject condensate. This improves heat transfer efficiency. Other aspects of the tube also improve heat transfer efficiency.

  When transferring heat from the condensed vapor outside the tube to the coolant inside the tube, heat transfer is considered in several different steps. The same basic steps can be applied when transferring heat between any two media having different temperatures through a barrier such as a tube wall. This description relates to condensed vapor outside the tube and coolant inside the tube, but different applications are possible.

  Steam outside the tube transfers heat to the coolant inside the tube. When steam liquefies, it releases a certain amount of heat, referred to as heat of condensation. Conversely, when a liquid evaporates into a gas, it absorbs a certain amount of heat, referred to as heat of evaporation. Condensation heat and evaporation heat are equal for a given quantity of a given substance, apart from the release of condensation heat and absorption of evaporation heat.

  Reference is now made to condensation in the tube. A layer of condensate is usually placed on the outer surface of the tube so that heat is transferred from the vapor in the tube to the condensate in the first step. Next, heat is transferred through the condensate. Because the condensate functions as a thermal insulator, it often becomes a resistance to heat transfer. Even if the liquid is a good conductor of heat, the layer of condensate still provides some resistance to heat transfer. Heat is transferred through the condensate and then from the condensate to the outer surface of the tube. There is a junction between the condensate and the outer surface of the tube, and every junction provides some resistance to heat transfer.

  As soon as heat is transferred to the outer surface of the tube, it is transferred from the outer surface of the tube to the inner surface. In order to promote this heat transfer, the heat transfer tube is typically formed from a material or heat conductor that promotes heat transfer. One material considered as a good thermal conductor is copper. Usually, there is a thin layer of liquid in contact with the inner surface of the tube wall, where liquid essentially does not flow. After the heat is transmitted through the tube wall, it is transferred to the adjacent coolant layer on the inner surface of the tube through a junction between the inner surface of the tube wall. The heat is then transferred through this thin layer of liquid adjacent to the tube wall to the body through which the liquid in the tube flows.

  The more turbulent or rapid the flow of liquid in the tube, the thinner the layer of liquid that will not flow and stays adjacent to the tube wall. Therefore, a tube design that mixes or stirs the liquid in the tube is beneficial. Turbulence promotes liquid mixing compared to laminar flow, and a larger liquid flow rate promotes turbulence. The properties at the inner surface of the tube also promote liquid turbulence and mixing within the tube. As the liquid flows out of the tube, the heat transferred to the liquid flowing in the tube is released.

  If the fin is configured separately from the tube and then attached, there is a junction between the fin and the tube. This is true even if the fins and tubes are composed of the same material such as copper or different materials. Every joint provides some resistance to heat transfer. In the case where the fin is formed from the tube wall, there is no need for a joint and heat transfer efficiency is improved. In this description, fins formed from the tube wall are referred to as being integral with the tube, and it is preferred that the fin and tube be integral to minimize resistance to heat transfer.

It is preferred that the tube be formed from a malleable material so that the fins are formed from the tube without forming cracks or cracks in the tube wall. Cracks or fissures limit the structural integrity and strength of the tube and further provide resistance to heat transfer. These tubes are typically used in shell and tube heat exchangers, and the ends of the tubes are added to the tube plate of the heat exchanger. The malleable tube can be easily attached by the heat exchanger tube sheet. Moreover, it is preferable that a pipe | tube is comprised from the substance which accelerates | stimulates heat transfer. Copper is often used in tube construction for its malleable and heat transfer properties.
Specific condensation considerations

  Finned tubes are considered for design with particular reference to condensate collection on the outer surface of the tube. Some tubes are superior to others in the ejection of condensate. If the condensate spouts more quickly, the condensate layer in the tube will become thinner and less resistant to heat transfer. Therefore, a condensing tube that ejects the condensate more quickly is preferable because it conducts heat more quickly.

  One aspect that allows the tube to eject the condensate more quickly is the external surface function that aggregates the condensate into droplets. This is often performed by a steep or curved portion on the outer surface. If the steep or curved portion is substantially concave, the surface tension collects the condensate on the concave surface features, which serves as a storage location for the condensate droplets. Due to the effect of surface tension, the condensate moves away from the convex area. For this reason, the condensate avoids convex surfaces. Therefore, the convex region remains relatively free of condensate and has a lower resistance to heat transfer. In order for the tube to eject the condensate more quickly, the concave area then aggregates the condensate into droplets that flow more quickly out of the tube. Curved or steep portions typically form both convex and concave surfaces at different locations.

Also, in fact, a larger surface area in the condenser tube makes heat transfer faster. When fins are formed on the tube, the surface area of the tube increases. Thereby, the heat transfer rate in the whole pipe | tube becomes large. Other deformations on the outer surface of the tube that increase the surface area of the tube also increase the heat transfer rate.
Specific evaporation principle

  The evaporator tube has design characteristics that are different from the specific design characteristics preferred for the condenser tube. The evaporator tube is usually immersed in the evaporating liquid so that it is not related to the ability to eject the condensate. For this reason, elements that improve evaporation provide a nucleation site for the initial formation of bubbles, a closed area that superheats the liquid, and a closed that can release vapor and introduce more liquid. The provision of holes or access ports that lead to other areas.

  Boiling nucleation sites often result in very small deficiencies or steep areas on the boiling surface. The closed area in the tube stores a relatively small amount of liquid so that it is substantially surrounded by the heat transfer surface provided by the finned tube. For this reason, the heat transfer area per volume of the liquid increases. This quickly heats the liquid to promote boiling or evaporation. Since vapor is less dense than liquid, liquid expands as it evaporates. If the evaporating liquid is closed, it generates pressure as it evaporates. Further, since the steam expands when heated, the pressure is increased by heating the steam in the closed region.

The small hole in the closed area allows a small amount of liquid to escape from it after evaporation, and the pressure generated by evaporation allows the vapor to be pushed out of the hole. Normally, surface tension reduces the liquid flowing through small holes unless there is a sufficiently large pressure differential to drive or push liquid through the holes. The vapor leaves a reduced pressure in the closed area that draws liquid through a small hole after discharge and the process is repeated. This functions as a kind of pumping action that draws liquid into the closed area and pushes the vapor out of the closed area.
Finned tube body

  A finned tube 10 according to one embodiment of the present invention is shown in FIGS. 1, 2 and 3 from different perspectives. While the description will focus on the embodiments shown below, this description is not intended to be limiting. Other embodiments that will be apparent to those skilled in the art are also possible.

Tube 10 includes a body 12 having an outer surface 14 and an inner surface 16. The body 12 provides a foundation for any shape or structure on the outer surface 14 or the inner surface 16. The body 12 is preferably formed from a material that promotes heat transfer. In general, metals are good conductors and are often used in the construction of the tubes of the present invention. As a metal used for the structure of the tube 10, copper is usually used. However, aluminum, other metals, various alloys, and non-metallic materials can also be used. The material is also preferably malleable so that various structures on the outer surface 14 and inner surface 16 are formed without damaging the integrity of the tube body 12. As a result, these structures are formed from the tube body 12 and are integrated with the tube body 12.
Tube fins

  The tube 10 has at least one fin 20 formed on its outer surface 14. The fins 20 typically protrude or extend from the outer surface 14 of the tube body. Usually, the fin 20 is spiral. The tube 10 often has an end without any fins 20 so as to easily achieve a seal between the end of the tube and the heat exchanger tubesheet. Usually these ends are flat. There is usually some transition region between the flat end of the tube 10 and the finned portion.

  A single single fin 20 may spiral around the entire length of the finned portion of the tube 10. A plurality of fins 20 may be wound around the tube 10 in a spiral shape. In either configuration, the cross-section of the outer surface 14 of the tube body appears as if there are a plurality of adjacent fins 20 that project out from the outer surface 14 of the tube body. When viewed from a direction parallel to the axial direction of the tube 10, the cross-sections of adjacent fins 20 may be the same fin 20 that spirally surrounds the outer surface 14 of the tube body. Despite the fact, it is referred to as the adjacent fin 20. Since the fin 20 is formed from the material of the tube body 12, the fin 20 has an integral structure with the tube body 12.

  Each fin 20 has several portions including a fin base 22, a fin upper end 24, and fin sidewalls 26. The fin base 22 is disposed at a position where the fin 20 is connected to the outer surface 14 of the pipe body. The fin upper end portion 24 is disposed on the opposite side of the fin base 22 and is the highest position in the fin 20 with respect to the axis of the tube 10. The fin side wall 26 includes a left side wall 28 and a right side wall 30 on the opposite side of the left side wall 28. A channel 32 is defined between two adjacent fins 20 on one side of the tube body 12 and has a channel center 34. Channel center 34 is equidistant from two adjacent fins 20 that form channel 32. The fin 20 is generally perpendicular to the tube body 12 so that it extends substantially straight out from the outer surface 14 of the tube body. In this example, the fins 20 extend radially from the tube 10. The fins 20 may also be arranged at other angles with respect to the outer surface 14 of the tube body.

The fin upper end 24 has a plurality of indentations 36 as best seen in FIGS. The recess 36 has a skew angle 38 defined by the angle of the recess 36 relative to the fin upper end 24. The skew angle 38 can range from 0 degrees to 90 degrees depending on whether the recess 36 is perpendicular to the fin 20 or whether the recess 36 is fixed at different angles to the fin 20. The indentation typically has a depth 40 ranging from 0.1 millimeters to 0.5 millimeters. A plurality of tips 42 are defined between adjacent recesses 36. When the recess 36 is formed in the fin upper end 24, a base 44 extending from the fin upper end 24 in the recess 36 is formed. Since the fin upper end portion 24 undulates together with the recess 36 and the tip end portion 42, the base 44 is disposed on the fin upper end portion 24. A plurality of platforms 44 define additional curvature, angle, and surface area at the fins 20.
Feather

  Referring now to FIGS. 1, 2, 3, and 5, the fin 20 includes a vane 50 that extends or protrudes from the fin sidewall 26 between the fin upper end 24 and the fin base 22. The blade 50 is close to the fin upper end 24 or the fin base 22, but is not disposed on the fin upper end 24 or the fin base 22, but is disposed near the center of the side wall 26. The vanes 50 are fixed substantially perpendicular to the fin sidewalls 26 or at other angles relative to the fin sidewalls 26. The vane has a height 52 defined as the distance from the fin base 22 to the upper surface 54 of the vane. If the vane 50 is fixed at an angle other than 90 degrees relative to the fin sidewall 26, the vane height 52 is defined as the distance from the fin base 22 to the highest point on the upper surface 54 of the vane.

  The blade 50 has a blade base 56 at a position where the blade 50 is connected to the fin side wall 26. The blade base 56 is generally substantially parallel to the fin base 22. However, the blade base 56 may be at an angle that is not parallel to the fin base 22. The blades 50 extend from the side wall 26 to the vicinity of the channel center 34. The vanes 50 extend from both the left side wall 28 and the right side wall 30 such that each vane 50 from adjacent fins 20 reaches into a channel 32 defined between adjacent fins 20. The vanes 50 extending into the channel 32 form a barrier 58 that divides the channel 32 into a lower channel 62 and an upper channel 60 above the lower channel 62. The barrier 58 that covers the lower channel 62 is not absolute, but typically provides a closed area that protects the fluid that flows freely outwardly therefrom and into the interior thereof. The blade 50 defines a hole 64 at a position where the blade 50 contacts. The hole 64 is preferably a smaller hole 64 than the larger hole 64 to the extent that it is not too small in order to limit the free flow of liquid. The vane 50 has a vane end 66 on the opposite side of the vane base 56, and the hole 64 is located between the opposite vane 50 end 66 extending into the same channel 32. .

  In one embodiment, the vanes 50 on one fin sidewall 26 include interchangeable upper and lower vanes 68 and 70. The upper surface 72 of the upper blade 68 is higher in position than the upper surface 74 of the lower blade 70. For this reason, the blades 50 form a notched pattern along the single fin side wall 26 similar to the pattern at the top of the castle wall. Regardless of whether the blade 50 is located at the top or bottom of the tube 10, the upper surface 72 of the upper blade 68 is farther from the outer surface 14 of the tube body than the upper surface 74 of the lower blade 70. For this reason, the upper surface 72 of the upper blade 68 is positioned higher than the upper surface 74 of the lower blade 70. Since the fin 20 has a left side wall 28 and a right side wall 30, the vane 20 is further described as a left vane 75 and a right vane 77. Accordingly, the upper blade 68 is further described as a left upper blade 76 and an upper right blade 78, and the lower blade 70 is further described as a left lower blade 80 and a right lower blade 82. Therefore, the barrier 58 is formed by the left blade 75 and the right blade 77 extending from the adjacent fins 20.

  Since the upper left blade 80 and the upper right blade 82 and the lower left blade 76 and the lower right blade 78 are arranged in a line, the end portions 66 of the lower left blade 80 and the lower right blade 82 are each in the vicinity of the channel center 34. In each other. Similarly, the end portions 66 of the upper left blade 76 and the upper right blade 78 face each other in the vicinity of the channel center 34. The lower left wing 80 and the lower right wing 82 contact near the channel center 34 to better form a barrier 58 that covers the lower channel 62. There may be a gap 84 between the upper left wing 76 and the upper right wing 78, but the upper left wing 76 and the upper right wing 78 also contact near the channel center 62. This gap 84 functions as a hole 64 in the barrier 58. Further, the upper blade 68 and the lower blade 70 can be alternated so that the upper left blade 76 faces the lower right blade 82 in the vicinity of the channel center 34 and vice versa. Further, the arrangement of the upper blades 68 and the lower blades 70 on the opposing fin side walls 26 may be random instead of a specific order related to each other.

  The hole 64 defined by the blades 50 is usually arranged at a position where the blades 50 intersect each other. The hole 64 is present at a position where the upper blade 68 and the lower blade 70 are in contact with each other along the fin side wall 26 and at a position where the fins 20 are in contact with each other in the vicinity of the channel center 34. For example, when all of the upper left blade 76, the upper right blade 78, the lower left blade 80, and the lower right blade 82 substantially contact at substantially the same position, three or more blades 50 exist in the hole 64. Contact is particularly common. For example, when the upper left blade 76 and the upper right blade 78 do not contact in the vicinity of the channel center 34, the hole 64 can be long.

  The size of the hole 64 is preferably not so large that the effect of the barrier 58 is weakened in the formation of the closed region. The closed region formed by the barrier 58, the two adjacent fins 20, and the outer surface 14 of the tube body promote liquid overheating and nucleate boiling, which significantly increases the boiling efficiency. However, some of the holes 64 are designed so that the size of the holes 64 does not become too small so that the vapor is released and the liquid enters the closed area. The hole 64 is preferably smaller than 0.2 square millimeters, and more preferably in the range of 0.01 square millimeters to 0.2 square millimeters. If the hole 64 is too large, the blade 50 does not function as the barrier 58 and the boiling efficiency is significantly reduced. In fact, if the hole 64 is too large, the vane 50 will only protrude into the channel 32 and will not form a barrier 58. The size of the hole 64 can be varied to better accommodate the particular material that evaporates. Thus, the tube is somewhat customized for a particular user or substance. Examples of other components designed for a particular material include the blade height 52 and the spacing between adjacent fins 20. It is preferred that the holes 64 have no greater than about 10% of the area of the barrier 58.

  The top channel 60 is defined by a barrier 58 at the bottom and either fin sidewall 26. The upper channel 60 is configured to be opened because the upper end is relatively open so that liquid can flow freely out of and into the upper channel 60. The upper end can include larger holes that are better suited to allow free flow of liquid, but a protrusion can be formed on a portion of the upper channel 60 at the upper end. The platform 44 in the recess 36 does not form a barrier 58 but forms a protrusion over the upper channel 60. The upper end of the upper channel 60 includes a continuous opening or hole 64 that is at least large enough to allow liquid to flow therethrough. The upper end of the upper channel 60 is preferably only about 50% fixed by the solid structure, and an opening larger than 0.2 square millimeters is formed in the upper channel 60.

Barrier 58 divides channel 32 into upper channel 60 and lower channel 62. The lower channel 62 is designed to be suitable for evaporation and the upper channel 60 is designed to be suitable for condensation. The lower channel 62 may be beneficial to some extent without significantly preventing condensation. The upper channel 60 can be beneficial to some extent without significantly hindering evaporation. This provides a finned tube 10 that is effective in transitioning between both evaporation and condensation stages.
Channel mark

  A channel mark 86 is formed on the outer surface 14 of the tube body within the fin channel 32. The channel mark 86 is typically a recess defined in the outer surface 14 of the tube body. The channel mark 86 is continuous or intermittent. The continuous channel mark 86 is typically in the form of a groove circumferentially formed around the tube 10 in the fin channel 32 and the intermittent channel mark 86 is defined in the fin channel 32. There are several inconspicuous depressions made. Channel mark 86 is shown intermittently. Channel marks 86 are typically arranged in a row to define channel lines 88. The channel line 88 is substantially parallel to the fin channel 32 or the fin base 22 or bends within the channel 32. Channel line 88 is defined by a column of channel marks 86.

  One channel line 88 or a plurality of channel lines 88 can exist in one fin channel 32. The channel line 88 is disposed on or near the channel center 34 to offset the channel center 34 near the fin base 22 or at any position therebetween. If more than one channel line 88 is present and the channel mark 86 is intermittent, the channel mark 86 may be present at the same time or interchangeable. When the channel marks 86 are present at the same time, they are arranged in a row facing each other as shown in the figure. When the channel marks 86 are exchangeable, the channel marks 86 in one channel line 88 are arranged in a line without facing the channel marks 86 of another channel line 88 in the same fin channel 32. Is done.

The channel mark 86 can have various shapes. They can be square, rectangular, trapezoidal, polygonal, triangular, or most any other shape. The channel mark 86 functions as a nucleation site for evaporation. It also functions as a nucleation site for condensation. The sharp and sharp corner channel marks 86 become deficient when bubbles begin to develop during evaporation. Also, the sharp or acute channel mark 86 facilitates droplet formation to provide a storage location for condensate. Further, the channel mark 86 increases the surface area so as to promote heat transfer. The channel marks 86 can extend into the tube body 12 and thus reduce the strength of the tube 10 by reducing the thickness of the tube body 12. Therefore, the channel mark 86 and the channel line 88 are arranged at a position where the thickness of the tube body 12 is large in the vicinity of the fin base 22.
Inner ridge

Heat transfer through the tube 10 is improved by transferring heat more efficiently between the inner surface 16 of the tube body and the liquid in the tube 10. To facilitate faster heat transfer, a ridge 90 is defined on the inner surface 16 of the tube body. The ridge 90 on the inner surface 16 is typically helical and has a deep portion 92 and a number of individuals. The number of individuals is the number of ridges 90 within a predetermined distance. The ridge 90 can also be fixed at different cutting angles relative to the tube axis. The population of the deep portion 92 and the ridge 90 can be changed, and the cutting angle is determined so that the coolant can swirl the inside of the tube 10. By increasing the amount of stirring in the coolant, the swirling liquid promotes heat transfer.
Tube forming process

  Finned tube 10 is typically formed from an associated smooth tube 10 with tube finning machines known in the art. The tube finning machine includes an arbor 94 as shown in FIG. 5 along with successive references FIGS. 1, 2 and 3. Tube finning machines often include three or more arbors 94 disposed around the tube 10. For this reason, the tube 10 is held in an appropriate position by the arbor 94. Arbors 94 are arranged and angled so that each complements the other. The tube is provided and supplied through a finning machine such that the tube wall 96 is positioned between the arbor 94 and the internal support 98. Arbor 94 deforms the outer surface 14 of the tube and an internal support 98 deforms the inner surface 16 of the tube. Arbor 94 functions as the shape of the tool's container, and in fact holds various tools or discs, and the tool contacts and shapes the outer surface 14 of the tube. Typically, the tube wall 96 rotates relative to the arbor 94 and moves axially with the internal support 96 as it rotates.

  Arbor 94 includes a number of fin-forming discs 100 that typically deform tube wall 96 in succession to form one or more helical fins 20 on the outer surface 14 of the tube. The continuous finning disc 100 penetrates deeply into the tube wall 96 so that the fins 20 are formed and pushed upward by the finning disc 100. The inner support 98 includes a recess 102 so that when the fins 20 are formed on the outer surface 14 of the tube, a helical ridge 90 is formed on the inner surface 16 of the tube.

After the finning disk 100 forms the fin 20, various other disks are further provided in the arbor 94 to deform and define the final tube 10 embodiment. These other remaining disks are included or removed as desired. Following finned disc 100, channel mark disc 104 is used to form channel mark 86 in channel 32 defined by adjacent fins 20. Following the channel mark disk 104, one or more blade forming disks 106 are used to form the blades 50 on the fin side surfaces 28 between the fin base 22 and the fin upper end 24. The blade forming disk 106 forms a blade 50 that will later become the lower blade 70. Following the vane forming disk 106, one or more vane discs 108 are arranged such that the fin sidewall 26 includes interchangeable upper vanes 68 and lower vanes that define a barrier 58 that forms the upper channel 60 and the lower channel 62. Upper blades 68 are formed. Next, the indentation disk 110 is attached to the arbor 94. The recess forming disk 110 forms a recess 36 in the fin upper end 24. In this way, various modifications in the original associated smooth tube 10 are realized. Other sequences that can achieve similar results and disc and tool designs apply.
Tube benefits

  The described tube 10 is efficient to be used as both an evaporation tube and a condensation tube. The tube 10 may be used for other purposes, but is useful as a tube 10 composed of two parts for condensation and evaporation. Some applications in heat transfer, such as certain heat pumps, require a heat exchanger that is used continuously for liquid evaporation and vapor condensation. The normal design for most evaporator tubes is different from the design for most condenser tubes, and vice versa. For this reason, a tube having both functions is beneficial. The outer surface of the tube 10 is usually used for phase transition using a cooling medium or a heat medium, which is usually a liquid flowing inside the tube 10.

  The upper channel 60 is most beneficial when the coolant flowing through the tube is used to condense the vapor at the outer surface 14. The outer surface 14 has fins 20 to increase the surface area and has various angles and sharp angles to facilitate condensation. These and sharp angles provide a region with surface tension that causes the condensate to become droplets. These droplets fall into the tube 10 more quickly as they form, so the tube 10 ejects the condensate more quickly. Both the upper channel 60 and the lower channel 62 between the fins 20 facilitate the flow of condensate so as to improve the efficiency of the droplets flowing out or falling from the tube 10. Thereby, this invention also improves the function which ejects a condensate.

  Fins 20, vanes 50, indentations 36, pedestals 44, and channel marks 70 all increase the surface area on the outer surface 14 of the tube. Because heat travels throughout the surface of the tube, the larger surface area improves heat transfer efficiency. Thus, any deformation in the outer surface 14 of the tube that increases the surface area improves heat transfer efficiency.

  The bottom channel 62 is most beneficial for evaporation, but the surface area and sharp corners of the top channel 60 are also beneficial. The liquid is superheated in a closed region defined by the barriers 58, adjacent fins 20, and the outer surface 14 of the tube body. The large surface area of the closed area encloses a relatively small volume in the filled liquid so that considerable heat can be transferred quickly to the closed liquid. This causes the closed liquid to overheat and boil. In addition, the channel mark 86 functions as a nucleation site in a closed region that further promotes boiling of the liquid.

  The liquid enters the closed region of the lower channel 62 through the hole 64 in the barrier 58. As the liquid evaporates, the volume expands and the pressure pushes the vapor that has exited through the hole 64. The released vapor leaves a low pressure in the lower channel 62 and the closed area that draws more liquid to repeat the process. In order for the entire lower channel 62 to function as a closed area for evaporation, the holes 64 are preferably arranged at regular intervals along the length of the barrier 58 to allow vapor and liquid to pass through. If the holes 64 do not pass through the barrier 58 at regular intervals, the liquid prior to evaporation can be prevented from flowing through a portion of the lower channel 62 to limit the evaporation efficiency of the tube 10. Interchangeable upper and lower blades 68 and 70 provide a number of blade intersections. This provides many locations for the holes 64 along the entire length of the barrier 58 and facilitates the evaporation efficiency of the tube 10.

  The angle and steep portion in the upper channel 60 serves as a nucleation site for boiling, and the large surface area facilitates heat transfer to the liquid. For this reason, the upper channel 60 facilitates the evaporation process. Since the upper channel 60 does not have a closed region, it does not have the same evaporation efficiency as the lower channel 62, but does not interfere with the evaporation process.

Since the ridge 74 causes coolant turbulence and vortexing, the inner surface 16 of the tube also promotes heat transfer. Turbulence and vortices cause mixing that minimizes laminar flow and minimizes the depth of the fluid layer directly adjacent to the inner surface 16 of the tube. Ridge 74 also increases the surface area of inner surface 16 to facilitate heat transfer. More ridge populations and / or larger ridge depths 76 improve heat transfer efficiency, while more ridge populations and / or deeper ridges 74 are more resistant to coolant flow through the tube 10. Increase Heat transfer slows down due to a decrease in the coolant flow rate. Therefore, the balance for the best heat transfer conditions is negotiated.
Exemplary dimensions

  Exemplary dimensions are described below to provide a concept for at least one embodiment of the present invention, but the dimensions in the present invention may vary.

  The distance between the fins is the distance between the center points of two adjacent fins 20, and this distance can range from 0.3 millimeters to 0.7 millimeters.

  The fins 20 have a thickness above the vanes 50, referred to as the fin thickness. This thickness can then range from 0.05 millimeters to 0.3 millimeters.

  The fin 50 has a height measured from the fin base 22 to the fin upper end 24 measured from the tip 42 when the fin has a recess 36. The fin height can then range from 0.5 millimeters to 1.5 millimeters.

  The vane 50 has a height 52 that is measured from the outer surface 14 of the tube body to the upper surface 54 of the vane. Including the difference in vane height 52 between upper vane 68 and lower vane 70 that ranges from 0.02 millimeters to 0.2 millimeters, the lower vane height 52 is between 0.15 millimeters and 0. The upper blade height 52 can range from 0.2 millimeters to 0.6 millimeters.

  The channel mark 70 has several external dimensions. They have a total length measured along the circumference of the tube 10. This total length can range from 0.1 millimeters to 1 millimeter. The channel mark 70 has a full width measured along the axis of the tube 10. This full width can range from 0.1 millimeters to 0.5 millimeters. The channel mark 70 has a deep portion that can be in the range of 0.01 millimeters to 0.2 millimeters.

  The recess 36 formed in the fin upper end 24 has a deep portion 40 that can vary in the range of 0.1 millimeters to 0.5 millimeters. The recess 36 has a width that can vary in a range from 0.1 millimeters to 1 millimeter.

  The ridge 74 formed on the inner surface 16 of the tube body has a height. This height can then range from 0.1 millimeters to 0.5 millimeters. The internal ridge angle to the axis can be fixed at 46 degrees and the ridge start can vary in the range of 8 to 50.

  The width of the upper blade 68 measured around the tube 10 along the blade base 56 can range from 0.1 millimeters to 1 millimeter, and the width of the lower blade 70 can be from 0.1 millimeters. It can range up to 1 millimeter.

  The hole 64 defined in the barrier 58 may have a region in the range of 0.01 square millimeters to 0.2 square millimeters.

  While the present invention has been described with respect to a limited number of embodiments, those skilled in the art having the benefit of this disclosure may make modifications to other embodiments that do not depart from the scope of the invention disclosed herein. Understand what you get. Accordingly, the scope of the invention is limited only by the appended claims.

Claims (14)

A tube body having an outer surface;
Extending from the outer surface of the tube body, defining channels, each of which is integral with the tube body, including fin upper ends, fin bases, and adjacent fins including left and right fin sidewalls;
A left vane extending from the left fin sidewall between the fin upper end and the fin bottom and comprising a plurality of replaceable upper left and lower left vanes, and the fin between the fin upper end and the fin bottom A barrier comprising a right vane extending from a right fin sidewall and comprising a plurality of interchangeable upper right vanes and right lower vanes , wherein the channel is divided into an upper channel and a lower channel; A barrier, wherein the wing and the right wing define a plurality of holes through the barrier; and
A plurality of indentations at the upper end of the fin,
A finned tube, wherein a tip is defined between the adjacent indentations, a plurality of platforms extend from the fin upper ends of the indentations, and the upper channel is open.   The finned tube of claim 1, wherein the hole has an area of up to 0.2 square millimeters. The finned tube according to claim 1 , wherein the upper left blade and the upper right blade are arranged in a row, and the lower left blade and the lower right blade are arranged in a row.   The finned tube of claim 1, further comprising a channel mark in the channel on an outer surface of the tube body.   The finned tube of claim 1, wherein the tube body includes an inner surface, and the finned tube further comprises a ridge on an inner surface of the tube body. A tube body having an outer surface;
A fin that extends from the outer surface of the tube body, is integral with the tube body, and includes a fin upper end, a fin base, and fin sidewalls;
A plurality of vanes extending from the fin side wall between the fin upper end and the fin base and having an upper surface thereof, further comprising a plurality of replaceable upper and lower vanes; A blade whose upper blade upper surface is farther from the outer surface of the tube body than the upper surface of the lower blade;
A plurality of tip portions at the upper end of the fin,
The fin further comprises adjacent fins defining a channel therebetween, the fin sidewall further comprises a left fin sidewall and a right fin sidewall, and the vane extends to the left extending from the left fin sidewall. A right vane extending from the vane and the right fin side wall, wherein the left vane and the right vane form a barrier dividing the channel into an upper channel and a lower channel, the vane being the barrier A finned tube in which a hole is defined through which an adjacent tip defines a recess in the upper end of the fin and a base extends from the upper end of the fin in the recess. The finned tube of claim 6 , wherein the hole has an area up to 0.2 square millimeters and the upper channel is open. The finned tube of claim 6 , further comprising a channel mark in the channel on an outer surface of the tube body. The finned tube of claim 6 , wherein the tube body further comprises an inner surface, and the finned tube further comprises a ridge on an inner surface of the tube body. A method of forming a finned tube comprising:
(A) providing a tube having an outer surface;
(B) forming a helical fin including a fin side wall, a fin upper end, and a fin base on the outer surface of the tube;
(C) forming a plurality of replaceable upper and lower blades on the fin side wall between the fin upper end and the fin base,
It said fins, further comprising a fin adjacent to define a channel therebetween, the fin sidewalls further comprises a left fin sidewalls and right fin side walls, the vane, extend life and death from the left fin sidewall A left wing comprising a plurality of replaceable upper left and lower wings , and a right wing extending from the right fin sidewall and comprising a plurality of replaceable upper and lower right wings, The left and right vanes form a barrier that divides the channel into an upper channel and a lower channel, the vanes define a hole through the barrier, and adjacent tips are at the fin upper end. A method of defining a recess and a platform extending from an upper end of the fin in the recess. The method of claim 10 , further comprising forming a barrier formed from the vanes that intersects a channel defined by adjacent fins to divide the channel into an upper channel and a lower channel. . 12. The method of claim 11 , wherein (c) further comprises extending the vanes near a channel center such that a plurality of holes having a region of up to 0.2 square millimeters pass through the barrier. Method. The method of claim 10 , further comprising forming channel marks on an outer surface of the tube. The method of claim 10 , further comprising forming a helical ridge on the inner surface of the tube.

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