TECHNICAL FIELD
This disclosure relates to indirect heat exchangers and, more specifically, relates to heat exchangers having pressure vessels that receive a pressurized fluid.
BACKGROUND
One type of indirect heat exchanger is a fin-and-tube heat exchanger having a tube and fins mounted to the tube. A fin-and-tube heat exchanger may be utilized in a cooling tower or other heat transfer apparatus to cool a process fluid from an industrial process, such as an HVAC system, a manufacturing process, or a computer data center. The tube operates as a pressure vessel and receives the process fluid, such as a water and glycol mixture, at a maximum pressure of 100 psi or greater, such as 150 psi, 350 psi, or even 1000 psi. A fin-and-tube heat exchanger may also be utilized in a cooling tower or other heat transfer apparatus to condense a process fluid such as R-134a or R744.
Some fin-and-tube heat exchangers utilize a tube of a high-conductivity material, such as brass or aluminum, to increase the efficiency of the heat exchanger. A tube of high-conductivity material, with a wall thickness sized to withstand an internal process fluid pressure of 100 psi or more, may be cost-prohibitive in some situations.
SUMMARY
In one aspect of the present disclosure, an indirect heat exchanger is provided that includes a plurality of fins having openings and a plurality of tubes connecting the fins. The indirect heat exchanger has spacings between the fins that permit a first fluid, such as air, to flow therethrough. The fins have outer portions outward of the tubes to be contacted by the first fluid as the first fluid flows through the spacings between the fins. The tubes have interiors aligned with the openings of the fins to permit a second fluid, such as a water/glycol mixture or a refrigerant such as R-134a or R744, to flow through the tubes and the openings of the fins. The fins have inner portions extending about the openings to be contacted by the second fluid. The fins are configured to transfer heat between the first fluid and the second fluid via direct contact between the outer portions of the fins and the first fluid and direct contact between the inner portions of the fins and the second fluid. Because the fins directly contact both the first and second fluids, the fins are able to transfer heat between the first and second fluids while the tubes keep the first and second fluids separated.
In one embodiment, the tubes are made of a first material and the fins are made of a second material, the second material having a higher thermal conductivity than the first material. For example, the tubes may be made of a plastic material such as CPVC and the fins may be made of a metallic material such as aluminum. Because the tubes and fins may be made of different materials, the efficiency and material cost of the indirect heat exchanger may be narrowly tailored for a particular embodiment.
In another aspect, a method is provided for manufacturing an indirect heat exchanger. The method includes forming an opening of a fin, the fin having an inner portion extending about the opening. The method further includes connecting tubes to opposite sides of the fin with interiors of the tubes aligned with the opening of the fin to permit a fluid to flow through the interiors of the tubes and the opening of the fin. The step of connecting the tubes to the opposite sides of the fin comprises positioning the inner portion of the fin to be contacted by the fluid as the fluid flows through the opening of the fin.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevational view of an indirect heat exchanger having a serpentine tube for receiving a process fluid and a mat of wires that provides extended surfaces to transfer heat from the process fluid to air contacting the mat of wires;
FIG. 2 is a cross-sectional view taken across line 2-2 in FIG. 1 showing plugs securing wires of the mat in openings of a side wall of the serpentine tube, the wires each having a portion in an interior of the tube to contact the process fluid and portion exterior of the tube to contact the air;
FIGS. 3, 4, and 5 are schematic views of cooling towers that may utilize an indirect heat exchanger having tubes and wires similar to the indirect heat exchanger of FIG. 2;
FIGS. 6A-6H are a series of schematic views of a method of manufacturing an indirect heat exchanger having a tube and a mat of wires;
FIGS. 7A-7D are a series of schematic views of a method of manufacturing an indirect heat exchanger having a tube and a mat of wires, the method including using a loom to direct the wires through runs of the tube;
FIG. 8 is a perspective view of an indirect heat exchanger having fins and tubes secured to the fins;
FIG. 9 is an exploded view of two of the tubes and one of the fins of FIG. 8, FIG. 9 showing a through opening in the fin that permits process fluid to travel from one tube, through a collar portion of the fin, and into the other tube;
FIG. 10 is a side elevational view of the fin of FIG. 9 showing the collar portion of the fin depending from a plate portion of the fin;
FIG. 11 is an indirect heat exchanger including a tube with holes and heat pipes extending through the holes to transfer heat between a process fluid in an interior of the tube and a fluid exterior of the tube;
FIG. 12 is a perspective view of an indirect heat exchanger having a tube and a fin that extends through slots in a sidewall of the tube;
FIG. 13 is a perspective view of an indirect heat exchanger having a flat fin and halves of a tube secured thereto;
FIG. 14 is an exploded view of the indirect heat exchanger of FIG. 13 showing longitudinal edges of the tube halves that are secured to the fin;
FIG. 15 is a perspective view of an indirect heat exchanger having a tube with openings, wires protruding from the openings, and an expanded liner in the tube that secures end portions of the wires to an interior surface of the tube;
FIG. 16 is a perspective view of the indirect heat exchanger of FIG. 15 prior to the liner being expanded;
FIG. 17 is a perspective view of an indirect heat exchanger having an outer tube and an expanded liner having portions of the liner protruding into through openings of a side wall of the tube;
FIG. 18 is a perspective view of the heat exchanger of FIG. 17 before the liner has been expanded;
FIG. 19 is a perspective view of a heat exchanger having an expanded liner and a helical support to resist rupture of the expanded liner upon the expanded metal liner receiving pressurized process fluid;
FIG. 20 is a perspective view of an indirect heat exchanger having a tube and a spiral fin that extends through a helical slot in a side wall of the tube;
FIG. 21 is a perspective view of an indirect heat exchanger having a tubular support and an expanded liner with wires that protrude outward through a side wall of the support;
FIG. 22 is a perspective view of the liner of FIG. 21 prior to expansion of the liner and showing wires that are pre-attached to a tubular side wall of the unexpanded liner;
FIG. 23 is a perspective view of an indirect heat exchanger having tubes, a fin, and o-rings;
FIG. 24 is an exploded view of an indirect heat exchanger of FIG. 23 showing a through opening of the fin that permits process fluid to flow from one tube, through the fin, and into the other tube;
FIG. 25 is a perspective view of an indirect heat exchanger having a tube and a metallic sleeve electroplated to the tube;
FIG. 26 is a perspective view of the support of FIG. 25 showing an electrically conductive paint applied to an exterior of the tube to facilitate electroplating;
FIG. 27 is a perspective view of an indirect heat exchanger having a tube molded onto a fin;
FIG. 28 is a plan view of the fin of the indirect heat exchanger of FIG. 27 showing a central opening to permit process fluid to flow therethrough and peripheral openings that permit material of the tube to flow through the fin during manufacture of the indirect heat exchanger;
FIG. 29 is a schematic view of a mold for forming the indirect heat exchanger of FIG. 27;
FIGS. 30-39 are views of a process of manufacturing an indirect heat exchanger;
FIG. 40 is a perspective view of an indirect heat exchanger having fins and multiple tubes molded to each fin;
FIG. 41 is a perspective view of a fin similar having multiple tubes molded therewith;
FIG. 42 is a schematic view of a hot water trough having fins upstanding from a floor of the trough to transfer heat from hot water in the trough to air contacting the fins;
FIG. 43 is an elevational view of an indirect heat exchanger having a tube with spike fins protruding from the tube to transfer heat between a process fluid in the tube and a fluid flowing over an exterior of the tube;
FIG. 44 is a cross-sectional view taken across line 44-44 in FIG. 43 showing epoxy mounted to a radially inner surface of the tube to secure the spikes to the tube;
FIG. 45 is a view similar to FIG. 44, FIG. 45 showing an alternative configuration wherein the epoxy is applied to a radially outer surface of the tube to secure the spikes to the tube;
FIG. 46 is an elevational view of an indirect heat exchanger having a tube that receives a process fluid and spike fins protruding therefrom to transfer heat between the process fluid and a fluid traveling over an exterior of the tube;
FIG. 47 is a cross-sectional view taken across line 47-47 in FIG. 46 showing epoxy beads applied to the spikes to secure the spikes to the tube;
FIGS. 48A-48D are cross-sectional views of indirect heat exchangers having tubes with different tube aspect ratios;
FIG. 49 is a perspective view of a plate-style indirect heat exchanger connected to inlet and outlet headers;
FIG. 50 is a perspective view of a heat transfer apparatus having a non-pressurized direct contact heat exchanger;
FIG. 51 is a cross-sectional of the heat transfer apparatus of FIG. 50 showing troughs of the heat exchanger that receive process fluid and fins for transferring heat from the process fluid to air traveling through the heat transfer apparatus;
FIG. 52 is a cross-sectional view of an indirect heat exchanger having a tubular support with radial openings, an outer metal liner, and an inner metal liner expanded outward through the radial openings and contacting the outer metal liner; and
FIG. 53 is a perspective view of an indirect heat exchanger having a thin conductive liner held against support rods by the hydrostatic pressure of process fluid in an interior of the liner.
DETAILED DESCRIPTION
Regarding FIG. 1, an indirect heat exchanger 10 is provided that includes a pressure vessel such as a tube 12 having an inlet end portion 14 to receive a process fluid in direction 16 and an outlet end portion 22 to return the process fluid in direction 24. For example, the inlet end portion 14 may be connected to an inlet header of a heat transfer apparatus such as a cooling tower and the outlet end portion 22 may be connected to an outlet header of the heat transfer apparatus. The heat transfer apparatus may have one or more indirect heat exchangers to transfer heat between the process fluid and another fluid, such as air traveling in direction 44 by one or more fans of the heat transfer apparatus.
The tube 12 includes runs 18 and return bends 20 connecting the runs 18. The tube 12 is made of a material having a low thermal conductivity such as below 200 W-M/K. Example materials include polyvinyl chloride (PVC) and steel. The return bends 20 may each be, for example, a single bend (e.g. a curved 180 degree bend) or multiple bends (e.g., two 90 degree bends connected by a straight section of the tube) that cooperate to transfer the process fluid from between the runs 18.
The indirect heat exchanger 10 further includes a mat of wires 30 associated with the tube 12. Regarding FIG. 2, the mat of wires 30 includes individual wires 32 made of a material having a high thermal conductivity, such as at least 150 W-m/K. For example, the material of the wires 32 may have a conductivity between 200 and 250 W-m/K. An example material of the wires 32 is an aluminum alloy. In another embodiment, less conductive materials may be used such as steel, copper, and carbon fibers.
The wires 32 are secured in openings 34 of a side wall 36 of the tube 12 via plugs 38. In one embodiment, the plugs 38 are epoxy plugs and the wires 32 are secured to the tube 12 using the method described below with respect to FIGS. 6A-6H.
Once the wires 32 have been secured to the tube 12 via the plugs 38, the wires 32 are tousled to form the mat of wires 30. The tousled wires 32 provide a matrix of material having a high thermal conductivity and openings between the material for air and/or another fluid to travel therethrough. In one embodiment, airflow may be directed in horizontal (e.g., directions 44, 46), vertical (e.g., directions 40, 42), or diagonal directions across the indirect heat exchanger 10 as shown in FIG. 1. Alternatively or additionally, airflow may be directed into or out of the page of FIG. 1. The tousled wires 32 create a turbulent flow of air in and around the mat of wires 30 which encourages heat transfer between the wires 32 and the airflow.
Regarding FIG. 2, each of the wires 32 has an end portion 50 protruding inward of an inner surface 54 of the tube 12 and is positioned in an interior 52 of the tube 12. The end portions 50 are positioned to be contacted by a process fluid 60 traveling in direction 16 through the interior 52 of the tube 12. In one example, the process fluid 60 is at a first temperature and the air contacting the mat of wires 30 is at a lower, second temperature. The wires 32 transfer heat from the end portions 50 of the wires 32 in the interior 52 toward end portions 51 of the wires 32 positioned outward from an outer surface 62 of the tube 12. In a second example, the process fluid 60 is in a vapor state at a condensing temperature and the air contacting the mat of wires 30 is at a lower, second temperature. The wires 32 transfer heat from the end portions 50 of the wires 32 in the interior 52 towards end portions 51 of the wires 32 positioned outward from an outer surface 62 of the tube 12, and, in doing so, decrease the vapor quality of the process fluid 60. The wires 32 may project from the outer surface 62 of the tube 12 a distance 70, such as 0.5 inches to approximately 1 inch, although longer wires 32 may be utilized for different applications. The wires 32 each have a length and the distance 70 the wire 32 projects outward from the tube 12 may be a majority of the length of the wire 32.
Regarding FIG. 3, a heat transfer apparatus 80 is provided having an air inlet 82, an air outlet 84, an indirect heat exchanger 86, and a fan 88 to direct airflow from the air inlet 82, across the indirect heat exchanger 86, and to the air outlet 84. The indirect heat exchanger 86 is similar to the indirect heat exchanger 10 and includes tubes 90 for receiving process fluid and wires 92 to transfer heat to the airflow before the airflow enters plenum 94.
Regarding FIG. 4, a heat transfer apparatus 100 is provided having an air inlet 102, an air outlet 104, and an indirect heat exchanger 106 that fills a plenum 108 of the heat transfer apparatus 100. The indirect heat exchanger 106 is similar to the indirect heat exchanger 10 and includes tubes 110 and wires 112 for transferring heat between a process fluid and the tubes 110 and air traveling from the air inlet 102 to the air outlet 104 due to operation of a fan 114 of the heat transfer apparatus 100.
Regarding FIG. 5, a heat transfer apparatus 120 is provided having an air inlet 122, an air outlet 124, a plenum 126, an indirect heat exchanger 128, and a fan 130. The indirect heat exchanger 128 includes tubes 130 with wires 132 projecting therefrom to transfer heat between process fluid in the tubes 130 and air traveling between the air inlet 122 and the air outlet 124. The indirect heat exchanger 128 has a non-traditional arrangement of tubes 130 which may permit additional tubes 130 and associated wires 132 to be utilized in the heat transfer apparatus 120. By contrast, the indirect heat exchanger 86 may have a similar overall size and shape as conventional fin-and-tube heat exchangers such that the indirect heat exchanger 86 may be utilized as a replacement for a fin-and-tube heat exchanger with minimal changes to the internal structure of the associated heat transfer apparatus.
Regarding FIG. 6A-6H, a method 149 is shown for forming an indirect heat exchanger 150 (see FIG. 6H) having a tube 152 and a mat of wires 154. Regarding FIG. 6A, the tube 152 has an initial, straight configuration with opposite ends 154, 156 and a side wall 158 extending therebetween. The tube 152 is made of a material having a low thermal conductivity, such as PVC or steel. Regarding FIG. 6B, the tube 152 is bent to form a bend 160 that connects runs 162, 164 of the tube 152. To facilitate bending of the tube 152, the tube 152 may be softened such as by heating the tube 152.
Regarding FIG. 6C, openings 170 are formed in the runs 162, 164 such as by drilling the openings 170 into the side wall 158 of the tube 152.
Regarding FIGS. 6D and 6E, a wire assembly 180 is formed for each of the openings 170 by applying an adhesive, such as epoxy 190, to individual wires 182. Other examples of adhesives that may be used include polyurethane and cyanoacrylate. The individual wires 182 have opposite end portions 184, 186 and an intermediate portion 188 therebetween. The individual wires 182 with epoxy 190 thereon are brought together so that the epoxy on the individual wires 182 a coalesce into a body 192 of epoxy.
Regarding FIGS. 6F and 6G, the wire assemblies 180 are each advanced into one of the openings 170 so that the end portions 186 of the wires 182 are in an interior of the tube 152 and the body 192 of epoxy is in the opening 170. Next, additional epoxy 200 is added to fill in the opening 170 and form a plug 202 of epoxy that supports the wire assembly 180 in the opening 170. The plug 202 is similar to the plug 38 discussed above. The end portions 184 of the wires 182 are exterior to the tube 152.
With reference to FIGS. 6G and 6H, the mat of wires 154 is formed by tousling the end portions 184 of the wires 182 that are external to the tube 152. The tousling may provide an even spatial distribution of the wires 182. The tousling may be performed using, for example, a brush or comb.
Regarding FIGS. 7A-7D, a method 210 is provided for forming an indirect heat exchanger 212 (see FIG. 7D) having a tube 214 and a mat of wires 216. The indirect heat exchanger 212 is similar to the indirect heat exchanger 150 discussed above.
Regarding FIG. 7A, the tube 214 is initially straight. The tube 214 has a side wall 220 extending between ends 222, 224 of the tube 214. The tube 214 is bent to form a bend 226 connecting runs 228, 230 of the tube 214.
Regarding FIG. 7C, a loom 250 is utilized that has a wire carrier 252, such as a rapier, projectile, or shuttle, configured to advance wires 254 through the runs 228, 230 of the tube 214. The wire carrier 252 punctures or otherwise advances a leading end portion 260 of each wire 262 through the side wall 220 of the tube 214. The wire carrier 252 may or may not be heated.
In one embodiment, each wire is advanced through the run 230 and the run 228 such that the wire has a trailing end portion 262 proximate and external to the run 230, the leading end portion 260 proximate and external to the run 228, and an intermediate portion 270 extending between the runs 230, 228. Each wire 262 further includes portions 280, 282 extending across the interiors of the runs 230, 228 to contact fluid traveling through the runs 230, 228.
Regarding FIG. 8, an indirect heat exchanger 300 is provided that includes tubes 302, 304, 306, 308, 310, 312 and fins 314, 316. The tubes 304-312 each have interiors 320 to receive process fluid and are secured to the fins 314, 316 via epoxy 326. The tubes 302, 312 are made of a material having a low thermal conductivity, such as PVC, chlorinated polyvinyl chloride (CPVC), or steel, and the fins 314, 316 are made of a material having a high thermal conductivity such as aluminum. The fins 314, 316 each have an inner portion, such as a projecting portion such as collar portion 330 (see FIG. 9), and an outer portion, such as plate portion 332. The collar portion 330 extends into and along the interior 320 of the associated tube 302-312 such that the collar portion 330 of the fins 314, 316 directly contact the process fluid that travels through the tubes 302-312.
Regarding FIG. 9, the tubes 302, 306 are shown exploded from the fin 314. The collar portion 330 of the fin 314 extends about an opening 336 in the plate portion 332. The opening 336 permits the process fluid to travel from the interior 320 of the tube 302, along and in contact with an annular inner surface 331 of the collar portion 330, and into the interior 320 of the tube 306.
Regarding FIG. 10, the collar portion 330 may be formed by drawing the material of the fin 314 down and away from the plate portion 332. The drawing operation may also form the opening 336.
Regarding FIG. 11, an indirect heat exchanger 350 is provided that includes a tube 352 having an interior 354 to receive a first fluid and a side wall 356. The tube 352 is made of a material having a low thermal conductivity such as PVC. The heat exchanger 350 further includes heat pipes 360, 362 that extend through openings 364, 366, 368 in the side wall 356 of the tube 352. The heat pipes 360, 362 are secured to the tube 352 with epoxy 370, 372. The heat pipes 360, 362 each have end portions 380, 382 outward of an outer surface 384 of the side wall 356 and positioned to be contacted by a second fluid external to the tube 352 such as air or a liquid. Each heat pipe 360, 362 has an intermediate portion 390 extending across the interior 354 of the tube 352. The intermediate portion 350 directly contacts the first fluid in the interior 354 of the tube 352. The heat pipes 360, 362 are each configured to exchange heat between the second fluid contacting the end portions 380, 382 and the first fluid in the interior 354 of the tube 352. Each heat pipe 360, 362 utilizes vapor cycles to transfer heat between the intermediate portion 350 and the end portions 380, 382.
Regarding FIG. 12, an indirect heat exchanger 400 is provided that includes a tube 402 having an interior 404 and a side wall 406 extending thereabout. The heat exchanger 400 further includes a fin 408 extending through slots 410, 412 of the tube 402 and secured thereto via epoxy 414, 416. The tube 402 is made of a material having a low thermal conductivity, such as PVC or steel, and the fin 408 is made of a material having a higher thermal conductivity, such as aluminum.
The fin 408 has an intermediate portion 420 extending across the interior 404 and positioned to directly contact a first fluid in the interior 404 of the tube 402. The fin 408 further includes end portions 424, 426 protruding from an outer surface 428 of the tube 402 for being directly contacted by a second fluid exterior of the tube 402. The fin 408 transfers heat between the first fluid contacting the intermediate portion 420 in the tube interior 404 and the second fluid contacting the end portions 424, 426 of the fin 408. The fin 408 may extend diametrically across the interior 404 of the tube 402 or may be offset from a center of the tube 402 and extend as a cord if the tube 402 has a circular cross section.
Regarding FIG. 13, an indirect heat exchanger 450 is provided that includes a tube 452 and a fin 454. The tube 452 has halves 456, 458 that are secured to the fin 454 via epoxy 460, 462. The tube halves 456, 458 have interiors 466, 468 that receive a first fluid. The fin 454 has an intermediate portion 470 that is contacted by the first fluid in the interiors 466, 468 of the tube halves 456, 458. The fin 454 has portions 480, 482 protruding from the tube halves 456, 458 to be contacted by a second fluid external to the tube 452.
Regarding FIG. 14, the indirect heat exchanger 450 is shown with the tube halves 456, 458 exploded from the fin 454. The halves 456, 458 have longitudinal edges 490, 492, 494, 496 that are secured to the tube front and rear surfaces 497, 498 of the fin 454 via epoxy.
Regarding FIG. 15, an indirect heat exchanger 500 is provided that includes a support, such as a tube 502, an expanded liner 504 having an interior 506 to receive a first fluid, and wires 512 protruding from the tube 502 to contact a second fluid. The tube 502 is made of a material having a low thermal conductivity, such as PVC, and the expanded liner 504 and wires 512 are made of one or more materials having a higher thermal conductivity such as brass. Other materials that may be used for the expanded liner 504 and/or wires 512 are silver, bronze, and steel. The expanded liner 504 has been radially expanded tightly against a radially inner surface 508 of the side wall 510 of the tube 502 to secure wires 512 to the tube 502.
More specifically and with reference to FIG. 16, the liner 504 is shown in an unexpanded configuration and the wires 512 are positioned so that end portions 514 thereof extend in openings 516 of the tube 502. The metal liner 504 is made of copper or another ductile material that permits the metal liner 504 to be expanded, such as by introducing a high-pressure fluid into the interior of the unexpended liner 504. Expanding the metal liner 504 firmly engages a radially outer surface 530 of the tubular metal liner 504 against a radially inner surface 508 of the tube 502. The pressing of the radially outer surface 530 of the liner 504 against the radially inner surface 508 of the tube 502 captures the end portions 514 of the wires between the radially outer surface 530 of the metal liner 504 and the radially inner surface 508 of the tube 502. In this manner, the wires 512 are firmly fixed to the tube 502 and extend outward from the openings 516 such that end portions 540 thereof are exterior to the tube 502. The wires 512 may thereby contact the liner 504 and transfer heat from the first fluid in the interior 506 of the expanded liner 504 to the second fluid contacting the wires 512 external to the tube 502.
Regarding FIG. 17, an indirect heat exchanger 550 is provided that has a support, such as a tube 552, and an expanded liner 554. The tube 552 has openings 560 and the expansion of the liner 554 from an unexpanded configuration of FIG. 18 to the expanded configuration of FIG. 17 during manufacture of the indirect heat exchanger 550 forms portions, such as nubs 562, of the liner 554 that extend into the openings 560 of the tube 552. Once the liner 554 has been expanded to the configuration of FIG. 17, the expanded liner 554 has an interior 556 to receive a first fluid. The nubs 562 are contacted by a second fluid exterior of the tube 552 and facilitate indirect heat transfer between the first and second fluids. In one embodiment, the indirect heat exchanger 550 may be utilized in an evaporative heat exchanger.
The liner 554 is made of a material that is unable to withstand the internal pressure of the first fluid in the interior 556 of the expanded liner 554. The tube 552 inhibits further radial expansion and rupture of the tube 552.
Regarding FIG. 18, the liner 554 is shown in an interior 570 of the tube 552 in an unexpanded configuration. The liner 554 has a radially outer surface 572 of the liner 554 spaced from a radially inner surface 574 of the tube 552. The liner 554 is made of a metallic material, such as copper, aluminum, or steel.
Regarding FIG. 19, a heat exchanger 600 is provided that includes a support 602, such as a helical support, made of a material having a low thermal conductivity such as PVC. The indirect heat exchanger 600 further includes an expanded liner 604 made of a second material having a higher thermal conductivity than the support 602.
The expanded liner 604 has an interior 606 to receive a first fluid under pressure, such as greater than 50 psi. The support 602 inhibits radial expansion of the liner 604 beyond a predetermined configuration such that the indirect heat exchanger 600 can handle the pressurized first fluid in the interior 606 of the expanded liner 604.
The expanded liner 604 has a portion 608 covered by turns 614, 616 of the support 602 and an exposed portion 610 in an opening 612 between the turns 614, 616 of the support 602. The exposed portion 610 has a radially inner surface contacted by the first fluid in the interior 606 of the expanded liner 604 and a radially outer surface contacted by a second fluid exterior of the support 602. The expanded liner 604 thereby facilitates heat transfer between the first and second fluids at the exposed portion 610.
Regarding FIG. 20, an indirect heat exchanger 650 is provided that includes a tube 652 having a side wall 654 extending about an interior 656 that receives a first fluid. The indirect heat exchanger 650 further includes a spiral fin 657 having a portion 659 that extends inward into the interior 656 of the tube 652 via a helical slot 658 formed in the side wall 654 of the tube 652. In this manner, the portion 659 of the spiral fin 657 is positioned to directly contact a process fluid in the interior 656 of the tube 652. The spiral fin 656 is secured to the tube 652 via epoxy 670. The spiral fin 656 may thereby transfer heat between the process fluid in the interior 656 of the tube 652 and a fluid contacting the outer surfaces 672 of the spiral fin 657.
Regarding FIG. 21, an indirect heat exchanger 700 is provided having a support such as a tube 702 and an expanded liner 704. The liner 704 is shown in FIG. 22 in an unexpanded configuration and includes a tubular side wall 706 extending about an interior 708 and wires 709 attached to the tubular side wall 706. During assembly, the tubular side wall 706 is positioned in an interior 710 of the tube 702 and expanded which drives free ends 720 of the wires 709 outward through a side wall 722 of the tube 702. The tube 702 may be heated to soften the side wall 706.
The piercing or otherwise advancing of the wires 709 through the side wall 722 positions portions 730 of the wires 709 exterior to the tube 702. The wires 709 may thereby transfer heat between the process fluid in the interior 708 of the expanded liner 704 and a fluid contacting the wires 709 external to the tube 702.
Regarding FIG. 23, an indirect heat exchanger 750 is provided that includes a pressure vessel 752 for receiving a first fluid. The pressure vessel 752 includes tubes 754, 756, a fin 758, and seal members such as o-rings 770, 772. The fin 758 has an opening 762 that permits process fluid to flow between interiors 760 of the tubes 754, 756 and an opening 762 of the fin 758 as shown in FIG. 24.
The o-rings 770, 772 are sandwiched between the tubes 754, 756 and the fin 758. The indirect heat exchanger 750 may be secured together at least in part by a clamping force applied to the tubes 754, 756 to keep the o-rings 770, 772 sandwiched between the tubes 754, 756.
Regarding FIG. 25, an indirect heat exchanger 800 is provided having an interior 802 to receive a first fluid and an exterior surface 804 that is contacted by a second fluid. The indirect heat exchanger 800 includes a support such as a tube 806. The indirect heat exchanger 800 includes an electroplated metal layer 820 applied to the tube 806.
Regarding FIG. 26, the tube 806 is shown before the electroplated metal layer 820 has been applied to the tube 806. The tube 806 has a side wall 808 having through openings 810 and an interior 812. Regarding the enlarged area of FIG. 26, the side wall 808 of the tube 806 has an electrically conductive paint 814 applied to a radially outer surface 816 thereof.
Regarding an enlarged portion of FIG. 25, the electroplated metal layer 820 has been applied to the electrically conductive paint 814 on the side wall 808. The electroplated metal layer 820 includes portions 830 covering the openings 810 in the side wall 808 of the tube 806 that are formed during the electroplating process. Although the tube 806 is made of a material having a low electrical conductivity, such as PVC, the electrically conductive paint 814 permits the electroplated metal layer 820 to be applied to the tube 806. The portions 830 of the electroplated metal layer 820 have radially inner surfaces contacted by the first fluid in the interior 802 of the indirect heat exchanger 800 and a radially outer surface contacted by a second fluid exterior of the indirect heat exchanger 800.
Regarding FIG. 27, an indirect heat exchanger 850 is shown having a tube 852 molded onto a fin 851. The tube 852 is made of a material having a low thermal conductivity, such as a plastic such as PVC, and the fin 851 is made of a material having a higher thermal conductivity, such as a metal such as metal. The tube 852 has tube portions 854, 856 on opposite sides of the fin 851 and have a unitary, one-piece construction.
Regarding FIG. 28, the fin 851 is shown prior to the tube 852 being molded thereto. The fin 851 has a central opening 860 that permits fluid to flow between interiors of the tube portions 854, 856. Further, the fin 851 has peripheral openings 862 that permit the material of the tube 852 to flow through the fin 851 during the molding process.
Regarding FIG. 29, a mold 880 is provided that may be used to mold the tube 852 to the fin 851. The fin 851 has opposite surfaces 882, 884 that are clamped between portions 886, 890 of the mold 880. The mold 880 has a cavity 892 with a first tube portion 894 for forming the tube portion 854 and a second tube portion 896 for forming the tube portion 856.
In one approach, the process of molding the tube 852 includes advancing the material of the tube 852 into first tube portion 894 of the cavity 892, permitting the material to flow through the peripheral openings 862 of the fin 851, and advancing the material of the tube 852 into the second tube portion 896.
Turning to FIG. 39, an indirect heat exchanger 900 is provided having a pressure vessel 903 having an interior 908 to receive a first fluid under a pressure of, for example, 100 psi or higher. The pressure vessel 903 includes tubes 902, 904 and collar portions 940 (see FIG. 38) of fins 906. The fins 906 are textured, such as having a v-waffle surface texture.
The collar portions 940 of the fins 906 directly contact the process fluid in the interior 908 and transfer heat between the process fluid in the interior 908 and a fluid contacting external surfaces 910 of the fins 906, such as air being directed across the fins 906.
Regarding FIGS. 30-38, a method of forming the indirect heat exchanger 900 is provided. Regarding FIGS. 30 and 31, the method 920 includes providing a sheet 922 of metal and imparting a surface pattern, such as a v-waffle pattern, to the sheet 922 as shown in FIG. 31. The sheet 922 has valleys 924 and peaks 926.
Regarding FIG. 32, the sheet 922 is stamped to form a flattened portion 930 in the center of the sheet 922. Next, a hole 932 is formed in the flattened portion 930 of the sheet 922 as shown in FIG. 33.
Regarding FIG. 34, the method 920 includes completing the fin 906 by drawing a collar portion 940 of the sheet 922 downward from the flattened portion 930 and forming an opening 942.
Regarding FIG. 35, the method 920 includes applying a seal member such as epoxy 943, such as a first ring of epoxy, to a first surface portion 944 of the flattened portion 930 of the sheet 922. In other embodiments, other seal members may be used such as materials that are fluid resistant and able to withstand operating temperatures and pressures. For example, a butyl sealant may be used instead of epoxy.
Examples of materials for seal members include ethylene propylene diene monomer (EPDM), EPDM rubber, ethylene propylene copolymer (EPM), EPM rubber, IIR, and/or isobutylene tripolymer. Suitable materials may include one or more rubber polymer and/or thermoplastic materials. Some seal members may include a tackifier (e.g., rosin), a pigment (e.g., carbon black), a filler (e.g., calcium carbonate), and/or a vulcanizing agent (e.g., sulfur).
Regarding FIG. 36, the method 920 further includes applying epoxy 946, such as a second ring of epoxy, to an opposite, second surface portion 948 of the flattened portion 930 of the sheet 922.
Regarding FIG. 38, the tube 904 is fit onto the collar portion 940 and secured in place via the epoxy 946. The collar portion 940 has an outer diameter slightly smaller than the inner diameter of the tube 904 to permit the tube 904 to fit snugly onto the collar portion 940.
Turning to FIG. 37, on the opposite side of the sheet 922, the tube 902 is secured to the first surface portion 944 via the epoxy 946.
In one embodiment, the tubes 902, 904 are made of aluminized steel and are welded to sheet 942. In another embodiment, the tubes 902, 904 are made of steel and are braised to sheet 942. In yet another embodiment, the tubes 902, 904 are made of steel and are welded to the sheet 942 using a welding process such as friction stir welding, a bimetallic transition joint, cold metal transfer, or explosion welding as some examples.
The tubes 902, 904 have free ends 960, 962 (see FIG. 38) that are secured to adjacent fins 906 using epoxy in a manner similar to the process of attaching the tubes 902, 904 to the sheet 922 discussed above.
Regarding FIG. 40, an indirect heat exchanger 1000 is provided having fins 1002 with multiple pressure vessels 1004 formed therein by tubes 1006 secured to the fins 1002 via a process similar to the indirect heat exchanger 900 discussed above. FIG. 41 is a perspective view of a fin 1050 of another indirect heat exchanger assembly having columns of pressure vessels 1052 formed by tubes 1054 secured to the fin 1050.
Regarding FIG. 42, a hot water basin 1100 is provided that includes a trough 1102 made of a low thermal conductivity material such as PVC. The hot water basin 1100 further includes fins 1104 made of a material having a high thermal conductivity, such as aluminum, with base portions 1106 secured to a floor 1108 of the trough 1102. The fins 1104 have free end portions 1110 opposite the base portions 1106 and opposite surfaces 1114, 1116. The hot water basin 1100 includes an evaporative barrier 1116 that limits evaporation of water 1118 from the trough 1102. The water 1118 is advanced in direction 1120 through the trough 1102 and contacts the base portions 1106 of the fins 1104 submerged in the water 118. Cooler air is directed in direction 1130 across intermediate portions 1132 and removes heat from the fins 1104 that has been collected via the base portions 1106 submerged in the water 1118.
With reference to FIGS. 43 and 44, an indirect heat exchanger 1150 is provided that includes a tube 1152 of a material having a low thermal conductivity, such as PVC. The tube 1152 has an interior 1154 to receive a first fluid and a side wall 1156 extending about the interior 1154 and having openings 1158 formed therein. The indirect heat exchanger 1150 includes fins, such as spikes 1160, that extend through the openings 1158 of the side wall 1156. The spikes 1160 may be shot or otherwise advanced through the side wall 1156 to form the openings 1158 when the side wall 1156 has been softened such as by heating.
Regarding FIG. 44, the spikes 1160 each have a portion 1162 in the interior 1154 of the tube 1152 to contact the first fluid and a portion 1164 exterior of the tube 1152 to contact a second fluid. The spikes 1160 are made of a material having a higher thermal conductivity than the material of the tube 1152. The spikes 1160 transfer heat between the first and second fluids. The spikes 1160 are secured to the tube 1152 via epoxy 1170 applied to an inner surface 1172 of the tube 1152 such as by flowing the epoxy along the inner surface 1172 after the spikes 1160 have been positioned in the openings 1158. Alternatively or additionally, an epoxy 1180 may be applied to an outer surface 1182 of the tube 1152 to secure the spikes 1160 to the tube 1152 as shown in FIG. 45.
Turning to FIGS. 46 and 47, an indirect heat exchanger 1200 is provided that is similar to the indirect heat exchanger 1150. The indirect heat exchanger 1200 has a tube 1202 with a side wall 1203 and fins, such as spikes 1204 advanced through the side wall 1203 during manufacture of the indirect heat exchanger 1200. The indirect heat exchanger 1200 has epoxy 1206, such as an epoxy bead, at each spike 1204 to secure the spike 1204 to the tube 1202. The epoxy 1206 may be applied to each spike 1204 after the spikes 1204 have been advanced through the side wall 1203.
Alternatively, the epoxy 1206 or another sealant may be positioned on each spike 1204 prior to the spike 1204 piercing the side wall 1203. The epoxy 1206 is then melted onto the tube 1202 by, for example, heating the spikes 1204 and/or tube 1202.
Regarding FIGS. 48A-48D, indirect heat exchangers 1250, 1252, 1254, 1256 are provided that are similar to the indirect heat exchangers discussed above and include tubes 1258, 1260, 1262, 1264 with different aspect ratios. A given tube may have the same aspect ratio throughout or may have different aspect ratios at different locations along the tube.
A plate indirect heat exchanger 1300 is provided in FIG. 49. The plate indirect heat exchanger 1300 has a body 1302 including two joined plates that define an interior to receive process fluid. One or both of the plates of the body 1302 has wires 1304 protruding from the body 1302 and having portions in the interior of the body 1302 to directly contact the process fluid. An inlet header 1306 to provide process fluid to the interior of the body 1302 and an outlet header 1308 receives process fluid from the interior of the body 1302. The plate indirect heat exchanger 1300 may include multiple bodies 1302 joined to the same inlet header 1306 and outlet header 1308. For example, the inlet header 1306 and outlet header 1308 may be tubes that extend through openings of the plates of the bodies 1302 and have openings in the side walls of the tubes that permit process fluid to flow out of or into the tubes.
Regarding FIG. 50, a heat transfer apparatus 1350 is provided having an outer structure 1352, air inlets 1354, an air outlet 1356, and a fan 1358 to cause airflow from the air inlets 1354 to the air outlet 1356. The heat transfer apparatus 1350 has a non-pressurized direct contact heat exchanger 1359 that includes external hot water basins 1360 which receive heated process fluid and are similar to the hot water basin 1100 discussed above. Regarding FIG. 51, the non-pressurized direct contact heat exchanger 1359 further includes a series of internal hot water basins 1362 that receive process fluid from the external hot water basins 1360. The hot water basins 1360, 1362 have fins 1364, 1366 to transfer heat from the process fluid in the hot water basins 1360, 1362 to the airflow traveling through the heat transfer apparatus 1350. The cooled process fluid is returned back to the industrial process, such as an HVAC system of a building.
Turning to FIG. 52, an indirect heat exchanger 1400 is provided that includes a tube 1402, an inner metal liner 1404, and an outer metal liner 1406. The tube 1402 is made of a low-thermal conductivity material such as PVC and the inner and outer metal liners 1404, 1406 are made of a higher thermal conductivity material such as brass. The tube 1402 has a side wall 1408 with openings 1410. During assembly, the inner and outer metal liners 1404 and 1406 are positioned onto the tube 1402 and the inner metal liner 1404 is hydrostatically expanded which causes portions 1412 of the inner metal liner 1404 to deform radially outward into the openings 1410 and contact portions 1414 of the outer metal liner 1406. In this manner, the deformed portions 1412 of the inner metal liner 1404 are able to transfer heat from the process fluid in the interior of the inner metal liner 1404 to the outer metal liner 1406.
Regarding FIG. 53, an indirect heat exchanger 1450 is provided that includes a thin conductive liner 1452 having an interior 1454 to receive a pressurized process fluid. The indirect heat exchanger 1450 has a support, such as rods 1456, resisting expansion of the thin conductive liner 1452. The thin conductive liner 1452 is held against the rods 1456 by hydrostatic pressure.
Uses of singular terms such as “a,” “an,” are intended to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. The terms “comprising,” “having,” “including,” and “containing” are to be construed as open-ended terms. It is intended that the phrase “at least one of” as used herein be interpreted in the disjunctive sense. For example, the phrase “at least one of A and B” is intended to encompass A, B, or both A and B.
While there have been illustrated and described particular embodiments of the present invention, it will be appreciated that numerous changes and modifications will occur to those skilled in the art, and it is intended for the present invention to cover all those changes and modifications which fall within the scope of the appended claims. For example, some tubes are shown having circular cross sections but it will be appreciated that the tubes may have non-circular cross sections, such as elliptical or polygonal shapes.
Patent Application
20250230986
