CA1150723A - Heat transfer surface and method of manufacture - Google Patents
Heat transfer surface and method of manufactureInfo
- Publication number
- CA1150723A CA1150723A CA000307146A CA307146A CA1150723A CA 1150723 A CA1150723 A CA 1150723A CA 000307146 A CA000307146 A CA 000307146A CA 307146 A CA307146 A CA 307146A CA 1150723 A CA1150723 A CA 1150723A
- Authority
- CA
- Canada
- Prior art keywords
- tube
- fins
- ridge
- ridges
- adjacent
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F13/00—Arrangements for modifying heat-transfer, e.g. increasing, decreasing
- F28F13/18—Arrangements for modifying heat-transfer, e.g. increasing, decreasing by applying coatings, e.g. radiation-absorbing, radiation-reflecting; by surface treatment, e.g. polishing
- F28F13/185—Heat-exchange surfaces provided with microstructures or with porous coatings
- F28F13/187—Heat-exchange surfaces provided with microstructures or with porous coatings especially adapted for evaporator surfaces or condenser surfaces, e.g. with nucleation sites
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B21—MECHANICAL METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL; PUNCHING METAL
- B21C—MANUFACTURE OF METAL SHEETS, WIRE, RODS, TUBES OR PROFILES, OTHERWISE THAN BY ROLLING; AUXILIARY OPERATIONS USED IN CONNECTION WITH METAL-WORKING WITHOUT ESSENTIALLY REMOVING MATERIAL
- B21C37/00—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape
- B21C37/06—Manufacture of metal sheets, bars, wire, tubes or like semi-manufactured products, not otherwise provided for; Manufacture of tubes of special shape of tubes or metal hoses; Combined procedures for making tubes, e.g. for making multi-wall tubes
- B21C37/15—Making tubes of special shape; Making tube fittings
- B21C37/20—Making helical or similar guides in or on tubes without removing material, e.g. by drawing same over mandrels, by pushing same through dies ; Making tubes with angled walls, ribbed tubes and tubes with decorated walls
- B21C37/207—Making helical or similar guides in or on tubes without removing material, e.g. by drawing same over mandrels, by pushing same through dies ; Making tubes with angled walls, ribbed tubes and tubes with decorated walls with helical guides
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23P—METAL-WORKING NOT OTHERWISE PROVIDED FOR; COMBINED OPERATIONS; UNIVERSAL MACHINE TOOLS
- B23P15/00—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass
- B23P15/26—Making specific metal objects by operations not covered by a single other subclass or a group in this subclass heat exchangers or the like
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F28—HEAT EXCHANGE IN GENERAL
- F28F—DETAILS OF HEAT-EXCHANGE AND HEAT-TRANSFER APPARATUS, OF GENERAL APPLICATION
- F28F1/00—Tubular elements; Assemblies of tubular elements
- F28F1/10—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses
- F28F1/12—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element
- F28F1/24—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely
- F28F1/26—Tubular elements and assemblies thereof with means for increasing heat-transfer area, e.g. with fins, with projections, with recesses the means being only outside the tubular element and extending transversely the means being integral with the element
Abstract
ABSTRACT
A heat transfer surface for nucleate boiling of liquids is formed on the outer surface of a heat exchanger tube. Helical ridges having two fins each encase the tube. A fin at each ridge is angled toward the adjacent fin on the adjacent ridge forming a gapped cavity therebetween. The method of making the tube includes rolling alternating deep grooves and shallow grooves in the outside surface of the tube and then flaring the fins to form the gapped cavity.
A heat transfer surface for nucleate boiling of liquids is formed on the outer surface of a heat exchanger tube. Helical ridges having two fins each encase the tube. A fin at each ridge is angled toward the adjacent fin on the adjacent ridge forming a gapped cavity therebetween. The method of making the tube includes rolling alternating deep grooves and shallow grooves in the outside surface of the tube and then flaring the fins to form the gapped cavity.
Description
2;~
This invention relates to heat exchanger apparatus for use with a boiling liquid. More particularly this invèntion relates to a heat exchanger tube having a fluid to be cooled passing therethrough and a boiling refrigerant in contact with the external surface of the tube. The invention also relates to the method of manufacturing a tube of this particular configuration.
In certain refrigeration applications such as a chiller or an evaporator liquid to be cooled is passed through a tube while liquid refrigerant is in contact with the outside of the tube. Usually the tube is either immersed in re~rigerant or wetted with a refrigerant spray. The refrigerant changes state from a liquid to a vapor absorbing heat from the fluid to be cooled within the tube. The c;election of the external configuration of the tube is extremely influential in determining the boiling characteristics and overa]l heat transfer rate of the tube.
It has been found that the transfer of heat to a boiling liquid is enhanced by the creation of nucleate boiling sites. It has been theorized that the provision of vapor entrapment cavities in the heat exchanger surface creates sites ~or nucleate boiling.
In nucleate boiling the trapped vapor is superheated by the heat exchanger surface and consequently grows in size until surface tension is overcome and the vapor bubble breaks free from the surface. As the bubble leaves the surface, liquid wets the now vacated area and the remaining vapor has a source of additional liquid for creating vapor to form the next bubble.
The continual wetting and release together with the convection effect of the superheated bubble traveling through and mixing the liquid result in an improved heat transfer rate for the heat exchanger surface. "
It is known that the surface heat transfer rate is high in the area where the vapor bubble is formed. Consequently, the overall heat transfer rate tends to increase with the density of vapor entrapment sites per unit area of heat exchanger surface.
See for example, United States Patent No. 3,696,861 issued to Webb and entitled "Heat Transfex Surface Having A High Boiling Heat Transfer Coefficient", or Heat Transfer by M. Jakob, Vol. 1, published by John Wiley and Sons.
There are numerous heat transfer surfaces which utiliæe nucleate sites to enhance overall heat transfer rates. In United States Patent No. 3,454,081 granted to Kun and Czi~k entitled "Surface For Boiling Liquids", a cross-grooved boiling surface layer is created having sub-surface cavities with restricted openings to the outer surface of monoscopic density. In United States Patent No. 3,326,283 issuecl to Ware and entitled "Heat Transfer Surface", fins on tube are deformed to form indentations for the promotion of nuclPate boiling.
There are also many methods of creating nucleate boiling surfaces. In United States Patent No. 3,487,670 entitled, 'iM~thod of Forming Indentations In Fins Extending From A Heat Transfer Surface", a method is disclosed of forming the heat transfer surface in the Ware patent above. The fins are rolled with an indenting tool which flares the fin material beyond each side wall of the fin to form the vapor entrapment cavity. In United States Patent No. 3,496,752 granted to Kun the method includes scoring the heat transfer surface to form grooves of microscopic density and then forming cavities by deforming the material between the grooves into the grooves. In Webb, United States Patent No. 3,696,861, fins on a heat exchange tube are ~5~7~3 unidirectionally rolled over toward the adjacent fin to form vapor entrapment sites therebetween.
The creation of a cost effective high performance (nucleate boiling) heat exchanger tube that can be manufactured from a commercial tube blank in a single pass on a conventional tube finning machine is the problem resolved herein. In order for the tube to be cost effective, the additional expense in manufacturing the high performance tube must be recovered either in the decreased expense of construction utilizing the higher performance tube or in increased overall capacity of the heat exchanyer.
An object of the invention is to form a highly effective heat transfer surface.
Another object of the invention is to sustain nucleate boiling at a relatively high rate on a heat transfer surface.
Another object of the preser~t invention is to provide a high performance boiling tube which can be used with existing refrigeration equipment.
A still further object of the present invention is to provide an economical and durable heat exchanger tube having increased external surface area over a smooth tube.
Another object of the present invention is to provide a high performance nucleate boiling tube.
A still further object of the present invention is to provide a high performance tube which can be formed by a single rolling operation.
A further object of the present invention is to produce a high performance tube by rolling a conventional tube blank in a tube finning machine.
Other objects will be apparent from the description to follow and from the appended claims.
ô 2~
The preceding objects are achieved according to a preferred embodiment of the invention by the provision of alternating deep grooves and shallow grooves on the surface of a heat exchanger tube. A ridge is defined by adjacent deep grooves, the ridge having a base portion and two fins extending radially outward therefrom. The shallow groove separates the two fins extending ~rom the base poriton. The two fins of each ridge are bent in opposite directions toward the next adjacent fin on either side so that the fin partially encases the deep groove forming a single gapped cavity between adjacent ridges for promoting nucleate boiling.
The present invention is formed in a single pass through a conventional tube finning machine. A series of discs are mounted on a tool arbor in engagement with the tube passing through a tube finning machine. These~ discs are so arranged that alternating deep grooves and shallow grooves are first formed in the outer surface of the tube. Thereafter a flaring disc is applied to the shallow groove to force the fins outward over the deep grooves forming the gapped cavity between adjacent ridges.
Figure 1 is a partial sectional view of a smooth surface heat exchanger tube.
Figure 2 is a partial sectional view of the same tube as shown in Figure 1 after having the alternating shallow and deep grooves rolled therein.
Figure 3 is a partial sectional view of the same tube as shown in Figures 1 and 2 after having the fins flared to form the gapped cavities of the invention.
Figure 4 is a partial sectional view of the heat exchanger tube with the tool gang engaged therewith gang showing the progression of rolling discs and flaring discs utilized to ;23 form the shallow and deep grooves and the gapped cavities of the invention.
Figure 5 is a perspective view of a tool arbor having tool gang thereon shown skewed slightly to the tube being rolled.
The embodiment of the invention described below is adapted for use in a heat exchanger having a fluid to be cooled passing through a heat exchanger tube and simultaneously having a refrigerant to be vaporized in contact with the external surface of the tube. This heat transfer arrangement of fluid to be cooled and refrigerant can be found in an evaporator or chiller of a refrigeration system. In a typical application a plurality of parallel heat exchanger tubes are mounted such that several tubes form a fluid flow circuit and a plurality of parallel circuits are provided for the fluid to be cooled. Usually all the tubes of the various circuits are contained within a single casing wherein they are immersed in re!frigerant.
Referring now to the drawings, Figure 1 is a cross-sectional view of one wall of a smooth surface cylindrical tube prior to rolling. Figure ~ is a cross-sectional view of the same tu~e after alternating deep grooves 18 and shallow grooves 16 have been rolled therein. As a result of the rolling ridges 20 are formed, each ridge 20 constituting the part of the tube between adjacent deep grooves 18 which extends radially outward from an imaginary line drawn from the lowest point of a deep groove 18 to the lowest point of the adjacent deep groove 18. In figure 2 a ridge 20 is denoted as that part of the tube shown within the dotted line.
Ridges 20 each have a base portion 22 and two fins 24.
The base portion 22 is that part of ridge 20 that is located radially outward from an imaginary line connecting the lowest point of adjacent deep grooves and radially inward from an ~5~3 imaginary lin~ drawn between the lowest point of adjacent shallow grooves 16. Fins 24 are mounted to base portion 22 one on `each side of shallow groove 16 and extend radially outward from the imaginary line connecting the lowest points of adjacent shallow grooves 16.
Figure 3 is a cross-sectional view of the tube from Figures 1 and 2 having fins 24 flared to partially enclose cavities 30. Fins 24 have been angled away from the center of ridge 20 toward the adjacent ridge thereby partially covering deep groove 16. The pair of fins on each ridge are angled in opposite directions forming a narrow gap with the adjacent fin from the adjacent ridge. Gap 32, between the ends of the adjacent fins 24, is of such a dimension as to promote nucleate boiling within cavity 30. Cavity 30 is defined by the bottom of deep groove 18, the sides of adjacent base portions 22 and the sides of adjacent fins 24.
Ridges 20 are normally rolled in helical arrangement around tube 10. Thereby a single gapped cavity 30 is formed extending helically about the entire length of the heat exchanger tube. Of course, if double lead tooling is used two gapped cavities will extend the entire length of the heat exchanger tube. Obviously, more cavities may be provided by either increasing the number of leads in the tooling or by discontinuing the cavities at some location over the length of the tube, as for example to form lands on the tube surface whereby the tube may be held within a conventional tube sheet.
In Figure 4 the tool arrangement used within a conventional tube inning machine to roll this high performance tube is shown. In the conventional tube finning machine cylindrical discs are mounted on a multiplicity of tool arbors in such a manner that when rotated the discs displace portions of ~5~7~:3 the tube forming the desired configuration. From figure 4 it can be particularly seen that alternating deep grooves and sha`llow grooves are rolled into the surface of tube 10 by alternating deep groove discs 40 and shallow groove discs ~2, said discs progressing in depth as the tube proceeds along tool gang 38.
The specific number of rolling discs to achieve a specific width or depth of a particular groove or the number of tool arbors using multiple lead tooling is a design expedient as is the space, if any, between adjacent groups of discs. Also shown in figure 4 are a series of four flaring discs 44 for use with double lead tools, said discs being designed to fit within shallow groove 16 formed in ridges 20 on the surface of the tube such that the pair of fins 24 on each ridge are flared outwardly in opposite directions. It can be seen that the four flaring discs, a narrow and a wide disc on each set of double lead tooling, are arranged such that upon rolling the fins are progressively displaced. During flaring the gapped cavity 30 is formed by fins 24 being partially displaced to encase the groove 18 leaving a narrow gap 32 therebetween. It can be further seen in figure 4 that flare discontinuities 36 are produced at the bottom o~ shallow groove 16 when the fins 24 are flared. These flare discontinuities provide additional surface area and irregularities to promote nucleate boiling at sites other than cavities 30.
In a typical heat exchange application a copper tube having a .745 inch external diameter and a .0515 inch wall thickness would be utili2~d. After rolling and flaring the wall thickness measured at the bottom of the gapped cavity is approximately .028 inches.
Figure 5 shows an arbor 46 mounted so that its axis is skewed slightly to the axis of tube 10. Mounted on arbor 46 is tool gang 38 as shown in figure 4 and arbor nut 48 locking tool gang 38 and the appropriate spacers 50 in place on the arbor. As can be seen from figure 5 the axis of the tool arbor forms an acute angle appxoximating 3 degrees with the axis of tube 10.
This small amount of skew provides for tube 10 being driven along its axis as arbor 46 and the tool gang 38 thereon are rotated.
Consequently the tube 10 is moved through the tube finning machine (not shown) containing the tool gang and arbor as the arbor is rotated.
Within tube 10 is a conventional smooth mandrel (not shown~ for supporting the interior surface of the tube during rolling. The mandrel is of sufficient length that the interior surface of the tube is supported beneath all the discs on the tool arbor.
It is further obvious that as the tube proceeds along its axis, first the alternating deep grooves and shallow grooves are rolled progressively deeper into the tube surface and then the fins are f lared outwardly to form the gapped cavities, all rolling occurring in a single pass through the tube finning machine. In a typical application a plurality of tool arbors mounted about the circumference of the tube will be simultaneously utilized to provide smooth and consistent rolling.
The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
This invention relates to heat exchanger apparatus for use with a boiling liquid. More particularly this invèntion relates to a heat exchanger tube having a fluid to be cooled passing therethrough and a boiling refrigerant in contact with the external surface of the tube. The invention also relates to the method of manufacturing a tube of this particular configuration.
In certain refrigeration applications such as a chiller or an evaporator liquid to be cooled is passed through a tube while liquid refrigerant is in contact with the outside of the tube. Usually the tube is either immersed in re~rigerant or wetted with a refrigerant spray. The refrigerant changes state from a liquid to a vapor absorbing heat from the fluid to be cooled within the tube. The c;election of the external configuration of the tube is extremely influential in determining the boiling characteristics and overa]l heat transfer rate of the tube.
It has been found that the transfer of heat to a boiling liquid is enhanced by the creation of nucleate boiling sites. It has been theorized that the provision of vapor entrapment cavities in the heat exchanger surface creates sites ~or nucleate boiling.
In nucleate boiling the trapped vapor is superheated by the heat exchanger surface and consequently grows in size until surface tension is overcome and the vapor bubble breaks free from the surface. As the bubble leaves the surface, liquid wets the now vacated area and the remaining vapor has a source of additional liquid for creating vapor to form the next bubble.
The continual wetting and release together with the convection effect of the superheated bubble traveling through and mixing the liquid result in an improved heat transfer rate for the heat exchanger surface. "
It is known that the surface heat transfer rate is high in the area where the vapor bubble is formed. Consequently, the overall heat transfer rate tends to increase with the density of vapor entrapment sites per unit area of heat exchanger surface.
See for example, United States Patent No. 3,696,861 issued to Webb and entitled "Heat Transfex Surface Having A High Boiling Heat Transfer Coefficient", or Heat Transfer by M. Jakob, Vol. 1, published by John Wiley and Sons.
There are numerous heat transfer surfaces which utiliæe nucleate sites to enhance overall heat transfer rates. In United States Patent No. 3,454,081 granted to Kun and Czi~k entitled "Surface For Boiling Liquids", a cross-grooved boiling surface layer is created having sub-surface cavities with restricted openings to the outer surface of monoscopic density. In United States Patent No. 3,326,283 issuecl to Ware and entitled "Heat Transfer Surface", fins on tube are deformed to form indentations for the promotion of nuclPate boiling.
There are also many methods of creating nucleate boiling surfaces. In United States Patent No. 3,487,670 entitled, 'iM~thod of Forming Indentations In Fins Extending From A Heat Transfer Surface", a method is disclosed of forming the heat transfer surface in the Ware patent above. The fins are rolled with an indenting tool which flares the fin material beyond each side wall of the fin to form the vapor entrapment cavity. In United States Patent No. 3,496,752 granted to Kun the method includes scoring the heat transfer surface to form grooves of microscopic density and then forming cavities by deforming the material between the grooves into the grooves. In Webb, United States Patent No. 3,696,861, fins on a heat exchange tube are ~5~7~3 unidirectionally rolled over toward the adjacent fin to form vapor entrapment sites therebetween.
The creation of a cost effective high performance (nucleate boiling) heat exchanger tube that can be manufactured from a commercial tube blank in a single pass on a conventional tube finning machine is the problem resolved herein. In order for the tube to be cost effective, the additional expense in manufacturing the high performance tube must be recovered either in the decreased expense of construction utilizing the higher performance tube or in increased overall capacity of the heat exchanyer.
An object of the invention is to form a highly effective heat transfer surface.
Another object of the invention is to sustain nucleate boiling at a relatively high rate on a heat transfer surface.
Another object of the preser~t invention is to provide a high performance boiling tube which can be used with existing refrigeration equipment.
A still further object of the present invention is to provide an economical and durable heat exchanger tube having increased external surface area over a smooth tube.
Another object of the present invention is to provide a high performance nucleate boiling tube.
A still further object of the present invention is to provide a high performance tube which can be formed by a single rolling operation.
A further object of the present invention is to produce a high performance tube by rolling a conventional tube blank in a tube finning machine.
Other objects will be apparent from the description to follow and from the appended claims.
ô 2~
The preceding objects are achieved according to a preferred embodiment of the invention by the provision of alternating deep grooves and shallow grooves on the surface of a heat exchanger tube. A ridge is defined by adjacent deep grooves, the ridge having a base portion and two fins extending radially outward therefrom. The shallow groove separates the two fins extending ~rom the base poriton. The two fins of each ridge are bent in opposite directions toward the next adjacent fin on either side so that the fin partially encases the deep groove forming a single gapped cavity between adjacent ridges for promoting nucleate boiling.
The present invention is formed in a single pass through a conventional tube finning machine. A series of discs are mounted on a tool arbor in engagement with the tube passing through a tube finning machine. These~ discs are so arranged that alternating deep grooves and shallow grooves are first formed in the outer surface of the tube. Thereafter a flaring disc is applied to the shallow groove to force the fins outward over the deep grooves forming the gapped cavity between adjacent ridges.
Figure 1 is a partial sectional view of a smooth surface heat exchanger tube.
Figure 2 is a partial sectional view of the same tube as shown in Figure 1 after having the alternating shallow and deep grooves rolled therein.
Figure 3 is a partial sectional view of the same tube as shown in Figures 1 and 2 after having the fins flared to form the gapped cavities of the invention.
Figure 4 is a partial sectional view of the heat exchanger tube with the tool gang engaged therewith gang showing the progression of rolling discs and flaring discs utilized to ;23 form the shallow and deep grooves and the gapped cavities of the invention.
Figure 5 is a perspective view of a tool arbor having tool gang thereon shown skewed slightly to the tube being rolled.
The embodiment of the invention described below is adapted for use in a heat exchanger having a fluid to be cooled passing through a heat exchanger tube and simultaneously having a refrigerant to be vaporized in contact with the external surface of the tube. This heat transfer arrangement of fluid to be cooled and refrigerant can be found in an evaporator or chiller of a refrigeration system. In a typical application a plurality of parallel heat exchanger tubes are mounted such that several tubes form a fluid flow circuit and a plurality of parallel circuits are provided for the fluid to be cooled. Usually all the tubes of the various circuits are contained within a single casing wherein they are immersed in re!frigerant.
Referring now to the drawings, Figure 1 is a cross-sectional view of one wall of a smooth surface cylindrical tube prior to rolling. Figure ~ is a cross-sectional view of the same tu~e after alternating deep grooves 18 and shallow grooves 16 have been rolled therein. As a result of the rolling ridges 20 are formed, each ridge 20 constituting the part of the tube between adjacent deep grooves 18 which extends radially outward from an imaginary line drawn from the lowest point of a deep groove 18 to the lowest point of the adjacent deep groove 18. In figure 2 a ridge 20 is denoted as that part of the tube shown within the dotted line.
Ridges 20 each have a base portion 22 and two fins 24.
The base portion 22 is that part of ridge 20 that is located radially outward from an imaginary line connecting the lowest point of adjacent deep grooves and radially inward from an ~5~3 imaginary lin~ drawn between the lowest point of adjacent shallow grooves 16. Fins 24 are mounted to base portion 22 one on `each side of shallow groove 16 and extend radially outward from the imaginary line connecting the lowest points of adjacent shallow grooves 16.
Figure 3 is a cross-sectional view of the tube from Figures 1 and 2 having fins 24 flared to partially enclose cavities 30. Fins 24 have been angled away from the center of ridge 20 toward the adjacent ridge thereby partially covering deep groove 16. The pair of fins on each ridge are angled in opposite directions forming a narrow gap with the adjacent fin from the adjacent ridge. Gap 32, between the ends of the adjacent fins 24, is of such a dimension as to promote nucleate boiling within cavity 30. Cavity 30 is defined by the bottom of deep groove 18, the sides of adjacent base portions 22 and the sides of adjacent fins 24.
Ridges 20 are normally rolled in helical arrangement around tube 10. Thereby a single gapped cavity 30 is formed extending helically about the entire length of the heat exchanger tube. Of course, if double lead tooling is used two gapped cavities will extend the entire length of the heat exchanger tube. Obviously, more cavities may be provided by either increasing the number of leads in the tooling or by discontinuing the cavities at some location over the length of the tube, as for example to form lands on the tube surface whereby the tube may be held within a conventional tube sheet.
In Figure 4 the tool arrangement used within a conventional tube inning machine to roll this high performance tube is shown. In the conventional tube finning machine cylindrical discs are mounted on a multiplicity of tool arbors in such a manner that when rotated the discs displace portions of ~5~7~:3 the tube forming the desired configuration. From figure 4 it can be particularly seen that alternating deep grooves and sha`llow grooves are rolled into the surface of tube 10 by alternating deep groove discs 40 and shallow groove discs ~2, said discs progressing in depth as the tube proceeds along tool gang 38.
The specific number of rolling discs to achieve a specific width or depth of a particular groove or the number of tool arbors using multiple lead tooling is a design expedient as is the space, if any, between adjacent groups of discs. Also shown in figure 4 are a series of four flaring discs 44 for use with double lead tools, said discs being designed to fit within shallow groove 16 formed in ridges 20 on the surface of the tube such that the pair of fins 24 on each ridge are flared outwardly in opposite directions. It can be seen that the four flaring discs, a narrow and a wide disc on each set of double lead tooling, are arranged such that upon rolling the fins are progressively displaced. During flaring the gapped cavity 30 is formed by fins 24 being partially displaced to encase the groove 18 leaving a narrow gap 32 therebetween. It can be further seen in figure 4 that flare discontinuities 36 are produced at the bottom o~ shallow groove 16 when the fins 24 are flared. These flare discontinuities provide additional surface area and irregularities to promote nucleate boiling at sites other than cavities 30.
In a typical heat exchange application a copper tube having a .745 inch external diameter and a .0515 inch wall thickness would be utili2~d. After rolling and flaring the wall thickness measured at the bottom of the gapped cavity is approximately .028 inches.
Figure 5 shows an arbor 46 mounted so that its axis is skewed slightly to the axis of tube 10. Mounted on arbor 46 is tool gang 38 as shown in figure 4 and arbor nut 48 locking tool gang 38 and the appropriate spacers 50 in place on the arbor. As can be seen from figure 5 the axis of the tool arbor forms an acute angle appxoximating 3 degrees with the axis of tube 10.
This small amount of skew provides for tube 10 being driven along its axis as arbor 46 and the tool gang 38 thereon are rotated.
Consequently the tube 10 is moved through the tube finning machine (not shown) containing the tool gang and arbor as the arbor is rotated.
Within tube 10 is a conventional smooth mandrel (not shown~ for supporting the interior surface of the tube during rolling. The mandrel is of sufficient length that the interior surface of the tube is supported beneath all the discs on the tool arbor.
It is further obvious that as the tube proceeds along its axis, first the alternating deep grooves and shallow grooves are rolled progressively deeper into the tube surface and then the fins are f lared outwardly to form the gapped cavities, all rolling occurring in a single pass through the tube finning machine. In a typical application a plurality of tool arbors mounted about the circumference of the tube will be simultaneously utilized to provide smooth and consistent rolling.
The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.
Claims (17)
1. A thermally conductive surface for transferring heat to a boiling liquid in a heat exchange apparatus comprising: a wall; and ridges which are affixed to the wall, each ridge having a base portion connected to the wall and two fins mounted to the base portion, said fins of each ridge being angled in opposite directions toward but spaced from the closest fin of the next adjacent ridge so that a cavity is formed between adjacent ridges, one fin from each ridge serving to partially enclose the cavity to aid in the entrapment of vapor within the cavity for promoting nucleate boiling.
2. The invention as set forth in claim 1 wherein the base portion of the ridge extends radially outward from the wall and wherein the fins of the ridge are angled therefrom.
3. The invention as set forth in claim 2 wherein the wall is a cylindrical tube and wherein the ridges are an integral part of the tube formed in a helical configuration about the tube.
4. The invention as set forth in claim 3 wherein one or more helical cavities is formed extending the length of the tube between adjacent ridges.
5. A thermally conductive surface for transferring heat to a boiling liquid in a heat exchange apparatus comprising at least one gapped cavity wherein vapor is trapped to promote nucleate boiling, said cavity being defined by a wall and by spaced ridges affixed to the wall, the ridges having a base portion attached to the wall and fins mounted to the base portion such that a fin from each ridge is angled over the cavity forming a narrow gap therebetween.
6. The invention as set forth in claim 5 wherein the surface is cylindrical in shape and the cavity is helical about said surface.
7. The invention as set forth in claim 5 wherein the ridges are an integral part of the thermally conductive surface.
8. A heat exchanger comprising: a plurality of connected tubes for transferring heat from a relatively warm fluid within the tubes to a boiling fluid surrounding said tubes;
and helical ridges on said tubes, each ridge having a base portion integral with outer surface of the tube and having two-fins mounted on the base portion and integral therewith; the fins on each ridge being opposingly angled towards the next adjacent fin of the adjacent ridge so that a gapped cavity is formed by the outer surface of the tube, the base portion of the two adjacent ridges and by two fins, one fin from each adjacent ridge.
and helical ridges on said tubes, each ridge having a base portion integral with outer surface of the tube and having two-fins mounted on the base portion and integral therewith; the fins on each ridge being opposingly angled towards the next adjacent fin of the adjacent ridge so that a gapped cavity is formed by the outer surface of the tube, the base portion of the two adjacent ridges and by two fins, one fin from each adjacent ridge.
9. A method of forming a heat exchanger tube having integral ridges with fins angled in opposite directions to provide gapped cavities between the ridges comprising the steps of: providing a tubular blank of substantially circular cross-section; rolling the tubular blank to form alternating shallow grooves and deep grooves in the external surface thereof, the material between the deep grooves being a ridge having two fins as a part thereof; and flaring the fins of each ridge in opposite directions so that each fin extends over the deep groove on its respective side of the ridge forming a narrow gap with the flared fin from the adjacent ridge thereby converting the deep groove into a gapped cavity.
10. The method as set forth in claim 9 and further including the step of: translating the blank so that the step of rolling includes helical grooves being formed in the tube blank.
11. The method as set forth in claim 10 wherein the steps of rolling and flaring are accomplished by separate tools on the same tool arbor in an integral tube finning machine.
12. The method as set forth in claim 11 wherein steps of rolling and flaring further include using multiple tool arbors on a tube finning machine.
13. The method as set forth in claim 12 wherein the step of rolling includes forming two parallel ridges with double lead tools.
14. A method of forming a heat exchanger tube having integral ridges, each ridge having two fins angled in opposite directions to form gapped cavities between the ridges comprising the steps of: providing a tubular blank of substantially circular cross-section;
mounting the blank for rotational movement about its axis as well as movement in the direction of the axis;
locating rolling tools on a tool arbor adjacent to the blank;
making a plurality of deep grooves in the blank with a deep disc tool;
forming with a shallow disc tool a plurality of shallow grooves in the blanks, the shallow grooves being spaced between alternating deep grooves; and flaring with a flaring tool those parts of the blank between adjacent deep grooves which extend radially outward from the bottom of the shallow groove such that those parts angle over the deep grooves forming gapped cavities.
mounting the blank for rotational movement about its axis as well as movement in the direction of the axis;
locating rolling tools on a tool arbor adjacent to the blank;
making a plurality of deep grooves in the blank with a deep disc tool;
forming with a shallow disc tool a plurality of shallow grooves in the blanks, the shallow grooves being spaced between alternating deep grooves; and flaring with a flaring tool those parts of the blank between adjacent deep grooves which extend radially outward from the bottom of the shallow groove such that those parts angle over the deep grooves forming gapped cavities.
15. The method as set forth in claim 14 wherein the deep disc tool, the shallow disc tool and the flaring tool are all held in the same tool arbor and further including the step of: rotating the tool arbor and the tools thereon in rolling engagement with the tube forcing the tube to rotate therewith.
16. The method as set forth in claim 15 wherein the step of rotating includes the tool arbor axis being inclined at a slight angle to the tube axis so that upon rotation of the tool arbor the tube is rotated about its axis and simultaneously advanced in the direction of its axis whereby helical grooves are formed in the tube.
17. The method as set forth in claim 16 wherein the step of locating rolling tools includes multiple tool arbors being spaced about the tube and offset in the direction of the tube axis so that multiple lead grooves may be formed.
(18) A process for forming fins on a tube outer side which fins run circum-ferentially about the tube in a continuous fashion with their outer ends approaching the outer ends of adjacent fins forming a chamber between adjacent fins including the steps of:
displacing the material making up the tube wall in an outward direction by means of a rolling process, said rolling process being carried out by means of rolling discs positioned at the circumference of the tube;
notching the ends of the fins as they are being formed, said notching step being effected by means of a plurality of notching discs co-axially mounted in an alternating fashion with said rolling discs;
bending the ends of the notched fins into Y-fins, said bending step being effected by means of a bending roller mounted subsequent to said rolling and notching discs.
(19) A finned tube for heat exchangers or the like, of the type having circum-ferentially extending fins exteriorly of the tube and integral therewith, each fin having a base portion at which the fin merges with the exterior of the tube, the base extending generally radially outwardly from the wall of the tube, the base merging at its part remote from the exterior of the tube with a divergent radially outward portion, whereby the base and the radially outward portion define a generally Y-shaped cross-sectional configuration within a plane parallel with the axis of the tube, said fins being formed by a continuous ridge having said generally Y-shaped cross-section configuration, the ridge extending circumferentially about said tube and being of a generally uniform cross-section throughout its entire length.
(20) A finned tube as claimed in claim C19, wherein the base and the radially outward portion of the ridge are so shaped that two adjacent fins define there-between a chamber whose cross-sectional configuration is such that, proceeding from the exterior of the tube radially outwardly, the width of the chamber first increases and then decreases.
(21) A finned tube as claimed in claim C20, wherein a transition between the increasing and decreasing width of said chamber is smooth.
(22) A finned tube as claimed in claim C20, wherein the ridge is disposed helically about the tube.
(23) A finned tube as claimed in claim C22, wherein more than one ridge is provided and disposed in a multiple-thread fashion about the tube.
Applicant should note that if the conflict proceeds to the Section 45(5) stage then an affidavit will be required. Should applicant wish to include a certified copy of a corresponding foreign application as part of the affidavit, steps should now be taken to obtain such a copy.
(18) A process for forming fins on a tube outer side which fins run circum-ferentially about the tube in a continuous fashion with their outer ends approaching the outer ends of adjacent fins forming a chamber between adjacent fins including the steps of:
displacing the material making up the tube wall in an outward direction by means of a rolling process, said rolling process being carried out by means of rolling discs positioned at the circumference of the tube;
notching the ends of the fins as they are being formed, said notching step being effected by means of a plurality of notching discs co-axially mounted in an alternating fashion with said rolling discs;
bending the ends of the notched fins into Y-fins, said bending step being effected by means of a bending roller mounted subsequent to said rolling and notching discs.
(19) A finned tube for heat exchangers or the like, of the type having circum-ferentially extending fins exteriorly of the tube and integral therewith, each fin having a base portion at which the fin merges with the exterior of the tube, the base extending generally radially outwardly from the wall of the tube, the base merging at its part remote from the exterior of the tube with a divergent radially outward portion, whereby the base and the radially outward portion define a generally Y-shaped cross-sectional configuration within a plane parallel with the axis of the tube, said fins being formed by a continuous ridge having said generally Y-shaped cross-section configuration, the ridge extending circumferentially about said tube and being of a generally uniform cross-section throughout its entire length.
(20) A finned tube as claimed in claim C19, wherein the base and the radially outward portion of the ridge are so shaped that two adjacent fins define there-between a chamber whose cross-sectional configuration is such that, proceeding from the exterior of the tube radially outwardly, the width of the chamber first increases and then decreases.
(21) A finned tube as claimed in claim C20, wherein a transition between the increasing and decreasing width of said chamber is smooth.
(22) A finned tube as claimed in claim C20, wherein the ridge is disposed helically about the tube.
(23) A finned tube as claimed in claim C22, wherein more than one ridge is provided and disposed in a multiple-thread fashion about the tube.
Applicant should note that if the conflict proceeds to the Section 45(5) stage then an affidavit will be required. Should applicant wish to include a certified copy of a corresponding foreign application as part of the affidavit, steps should now be taken to obtain such a copy.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US05/815,116 US4159739A (en) | 1977-07-13 | 1977-07-13 | Heat transfer surface and method of manufacture |
| US815,116 | 1977-07-13 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1150723A true CA1150723A (en) | 1983-07-26 |
Family
ID=25216912
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000307146A Expired CA1150723A (en) | 1977-07-13 | 1978-07-11 | Heat transfer surface and method of manufacture |
Country Status (15)
| Country | Link |
|---|---|
| US (1) | US4159739A (en) |
| JP (1) | JPS5420450A (en) |
| AR (1) | AR216162A1 (en) |
| AU (1) | AU516021B2 (en) |
| BR (1) | BR7804497A (en) |
| CA (1) | CA1150723A (en) |
| CH (1) | CH630720A5 (en) |
| DE (1) | DE2829070C2 (en) |
| FR (1) | FR2397615A1 (en) |
| GB (2) | GB2001160B (en) |
| IN (1) | IN147952B (en) |
| IT (1) | IT1097006B (en) |
| MX (1) | MX146551A (en) |
| NL (1) | NL7807493A (en) |
| ZA (1) | ZA783702B (en) |
Families Citing this family (35)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4313248A (en) * | 1977-02-25 | 1982-02-02 | Fukurawa Metals Co., Ltd. | Method of producing heat transfer tube for use in boiling type heat exchangers |
| JPS53141958A (en) * | 1977-05-17 | 1978-12-11 | Hisaka Works Ltd | Plate type evaporator |
| DE2758526C2 (en) * | 1977-12-28 | 1986-03-06 | Wieland-Werke Ag, 7900 Ulm | Method and device for manufacturing a finned tube |
| DE2758527C2 (en) * | 1977-12-28 | 1985-04-25 | Wieland-Werke Ag, 7900 Ulm | Method and device for manufacturing a finned tube |
| DE2803274A1 (en) * | 1978-01-26 | 1979-08-02 | Wieland Werke Ag | FIBER TUBE AND THE METHOD AND DEVICE FOR THE PRODUCTION THEREOF |
| DE2803273A1 (en) * | 1978-01-26 | 1979-08-02 | Wieland Werke Ag | FIBER TUBE AND THE METHOD AND DEVICE FOR THE PRODUCTION THEREOF |
| US4219078A (en) * | 1978-12-04 | 1980-08-26 | Uop Inc. | Heat transfer surface for nucleate boiling |
| JPS5659194A (en) * | 1979-10-20 | 1981-05-22 | Daikin Ind Ltd | Heat transfer tube |
| GB2084308B (en) * | 1980-07-14 | 1983-11-30 | Cryoplants Ltd | Revapourising liquefied gas |
| US4545427A (en) * | 1982-05-24 | 1985-10-08 | Grumman Aerospace Corporation | Re-entrant groove heat pipe |
| US4549606A (en) * | 1982-09-08 | 1985-10-29 | Kabushiki Kaisha Kobe Seiko Sho | Heat transfer pipe |
| JPS59112199A (en) * | 1982-12-17 | 1984-06-28 | Hitachi Ltd | Heat-exchanging wall and manufacture thereof |
| US4577381A (en) * | 1983-04-01 | 1986-03-25 | Kabushiki Kaisha Kobe Seiko Sho | Boiling heat transfer pipes |
| GB2146930B (en) * | 1983-09-24 | 1987-04-23 | Eschweiler Bergwerksverein | A planetary skew-rolling mill |
| US4660630A (en) * | 1985-06-12 | 1987-04-28 | Wolverine Tube, Inc. | Heat transfer tube having internal ridges, and method of making same |
| DE3664959D1 (en) * | 1985-10-31 | 1989-09-14 | Wieland Werke Ag | Finned tube with a notched groove bottom and method for making it |
| GB2183519B (en) * | 1985-12-02 | 1989-10-04 | Carrier Corp | Method and apparatus for producing helically finned tubes |
| JPH0730963B2 (en) * | 1986-05-06 | 1995-04-10 | 株式会社東芝 | Helium cooling system |
| US6371199B1 (en) * | 1988-02-24 | 2002-04-16 | The Trustees Of The University Of Pennsylvania | Nucleate boiling surfaces for cooling and gas generation |
| US5351397A (en) * | 1988-12-12 | 1994-10-04 | Olin Corporation | Method of forming a nucleate boiling surface by a roll forming |
| US5018573A (en) * | 1989-12-18 | 1991-05-28 | Carrier Corporation | Method for manufacturing a high efficiency heat transfer surface and the surface so manufactured |
| EP0519886A1 (en) * | 1991-06-18 | 1992-12-23 | Ente per le nuove tecnologie, l'energia e l'ambiente ( ENEA) | Fluid-dynamic device, particularly for heat exchange |
| US6427767B1 (en) | 1997-02-26 | 2002-08-06 | American Standard International Inc. | Nucleate boiling surface |
| EP0949478A3 (en) * | 1998-03-09 | 2000-03-01 | Nefit Fasto B.V. | Heat exchanger |
| US6382311B1 (en) | 1999-03-09 | 2002-05-07 | American Standard International Inc. | Nucleate boiling surface |
| US20040010913A1 (en) * | 2002-04-19 | 2004-01-22 | Petur Thors | Heat transfer tubes, including methods of fabrication and use thereof |
| PT1692447E (en) * | 2003-10-23 | 2009-07-13 | Wolverine Tube Inc | Method and tool for making enhanced heat transfer surfaces |
| US7119312B2 (en) * | 2004-07-09 | 2006-10-10 | Sedlmayr Steven R | Microwave fluid heating and distillation method |
| US20090134152A1 (en) * | 2005-10-27 | 2009-05-28 | Sedlmayr Steven R | Microwave nucleon-electron-bonding spin alignment and alteration of materials |
| JP2008045868A (en) * | 2006-07-21 | 2008-02-28 | Sumitomo Light Metal Ind Ltd | Heat exchanger for water heater, and its manufacturing method |
| US20080235950A1 (en) * | 2007-03-30 | 2008-10-02 | Wolverine Tube, Inc. | Condensing tube with corrugated fins |
| US20090294112A1 (en) * | 2008-06-03 | 2009-12-03 | Nordyne, Inc. | Internally finned tube having enhanced nucleation centers, heat exchangers, and methods of manufacture |
| US8875780B2 (en) | 2010-01-15 | 2014-11-04 | Rigidized Metals Corporation | Methods of forming enhanced-surface walls for use in apparatae for performing a process, enhanced-surface walls, and apparatae incorporating same |
| DE102014002829A1 (en) * | 2014-02-27 | 2015-08-27 | Wieland-Werke Ag | Metallic heat exchanger tube |
| DE102014018817A1 (en) * | 2014-12-19 | 2016-06-23 | Schmöle GmbH | Method for providing a finned tube body of a heat exchanger and finned tube coil |
Family Cites Families (23)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| BE376635A (en) * | 1930-01-21 | |||
| GB415609A (en) * | 1932-10-28 | 1934-08-30 | British Aluminium Co Ltd | Improvements in or relating to heat-interchanger tubes |
| GB651465A (en) * | 1938-11-14 | 1951-04-04 | Brown Fintube Co | Improvements in and relating to heat-exchange conductors |
| GB670574A (en) * | 1940-03-12 | 1952-04-23 | Brown Fintube Co | Improvements in and relating to the manufacture of finned tubes |
| US3299949A (en) * | 1960-04-29 | 1967-01-24 | Thomson Houston Comp Francaise | Device for evaporative cooling of bodies, and particularly power vacuum tubes |
| GB1018228A (en) * | 1962-09-27 | 1966-01-26 | Brown Fintube Co | A finned tube heat exchanger |
| FR1444696A (en) * | 1964-12-17 | 1966-07-08 | Thomson Houston Comp Francaise | Improvements made to heat-dissipating walls and to devices comprising such walls |
| US3326283A (en) * | 1965-03-29 | 1967-06-20 | Trane Co | Heat transfer surface |
| US3487670A (en) * | 1965-03-29 | 1970-01-06 | Trane Co | Method of forming indentations in fins extending from a heat transfer surface |
| BE673408A (en) * | 1965-11-26 | |||
| FR1550992A (en) * | 1967-06-13 | 1968-12-27 | ||
| US3481394A (en) * | 1967-06-26 | 1969-12-02 | Calumet & Hecla Corp | Configuration of heat transfer tubing for vapor condensation on its outer surface |
| US3496752A (en) * | 1968-03-08 | 1970-02-24 | Union Carbide Corp | Surface for boiling liquids |
| US3566514A (en) * | 1968-05-01 | 1971-03-02 | Union Carbide Corp | Manufacturing method for boiling surfaces |
| US3454081A (en) * | 1968-05-14 | 1969-07-08 | Union Carbide Corp | Surface for boiling liquids |
| US3602027A (en) * | 1969-04-01 | 1971-08-31 | Trane Co | Simultaneous finning and reforming of tubular heat transfer surface |
| US3696861A (en) * | 1970-05-18 | 1972-10-10 | Trane Co | Heat transfer surface having a high boiling heat transfer coefficient |
| US3768290A (en) * | 1971-06-18 | 1973-10-30 | Uop Inc | Method of modifying a finned tube for boiling enhancement |
| JPS5325380B2 (en) * | 1975-02-07 | 1978-07-26 | ||
| GB1468710A (en) * | 1975-04-30 | 1977-03-30 | Atomic Energy Authority Uk | Methods of forming re-entrant cavities in the surface of heat exchange members or ebulators |
| US4050507A (en) * | 1975-06-27 | 1977-09-27 | International Business Machines Corporation | Method for customizing nucleate boiling heat transfer from electronic units immersed in dielectric coolant |
| DE2758527C2 (en) * | 1977-12-28 | 1985-04-25 | Wieland-Werke Ag, 7900 Ulm | Method and device for manufacturing a finned tube |
| DE2803274A1 (en) * | 1978-01-26 | 1979-08-02 | Wieland Werke Ag | FIBER TUBE AND THE METHOD AND DEVICE FOR THE PRODUCTION THEREOF |
-
1977
- 1977-07-13 US US05/815,116 patent/US4159739A/en not_active Expired - Lifetime
-
1978
- 1978-06-28 ZA ZA00783702A patent/ZA783702B/en unknown
- 1978-07-01 DE DE2829070A patent/DE2829070C2/en not_active Expired
- 1978-07-01 IN IN495/DEL/78A patent/IN147952B/en unknown
- 1978-07-07 AU AU37854/78A patent/AU516021B2/en not_active Expired
- 1978-07-10 JP JP8390778A patent/JPS5420450A/en active Granted
- 1978-07-11 IT IT25557/78A patent/IT1097006B/en active
- 1978-07-11 CA CA000307146A patent/CA1150723A/en not_active Expired
- 1978-07-11 FR FR7820657A patent/FR2397615A1/en active Granted
- 1978-07-12 GB GB7829672A patent/GB2001160B/en not_active Expired
- 1978-07-12 CH CH756178A patent/CH630720A5/en not_active IP Right Cessation
- 1978-07-12 GB GB8030869A patent/GB2085570B/en not_active Expired
- 1978-07-12 NL NL7807493A patent/NL7807493A/en not_active Application Discontinuation
- 1978-07-12 BR BR7804497A patent/BR7804497A/en unknown
- 1978-07-13 MX MX174162A patent/MX146551A/en unknown
- 1978-07-13 AR AR272940A patent/AR216162A1/en active
Also Published As
| Publication number | Publication date |
|---|---|
| BR7804497A (en) | 1979-03-06 |
| IT7825557A0 (en) | 1978-07-11 |
| FR2397615B1 (en) | 1983-05-27 |
| AU3785478A (en) | 1980-01-10 |
| US4159739A (en) | 1979-07-03 |
| AR216162A1 (en) | 1979-11-30 |
| GB2085570B (en) | 1982-10-20 |
| IN147952B (en) | 1980-08-23 |
| JPS6158757B2 (en) | 1986-12-12 |
| MX146551A (en) | 1982-07-07 |
| FR2397615A1 (en) | 1979-02-09 |
| NL7807493A (en) | 1979-01-16 |
| DE2829070C2 (en) | 1986-02-06 |
| CH630720A5 (en) | 1982-06-30 |
| AU516021B2 (en) | 1981-05-14 |
| ZA783702B (en) | 1979-07-25 |
| IT1097006B (en) | 1985-08-26 |
| GB2001160A (en) | 1979-01-24 |
| GB2085570A (en) | 1982-04-28 |
| GB2001160B (en) | 1982-10-13 |
| DE2829070A1 (en) | 1979-02-01 |
| JPS5420450A (en) | 1979-02-15 |
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Legal Events
| Date | Code | Title | Description |
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| MKEX | Expiry |