WO2006017167A2

WO2006017167A2 - Heat exchanger apparatus and methods for temperature control of high purity re-circulating liquids

Info

Publication number: WO2006017167A2
Application number: PCT/US2005/024246
Authority: WO
Inventors: Troy J. Orr
Original assignee: Purity Solutions Llc
Priority date: 2004-07-12
Filing date: 2005-07-08
Publication date: 2006-02-16
Also published as: US20060005955A1; WO2006017167A3

Abstract

A heat exchanger apparatus enables the temperature of a liquid located external to the apparatus in a recirculation loop to be controlled by heat transfer within the apparatus. The apparatus has heat transfer tubes (140) which may be helically wound around a fluid directional component (300). A manifold fitting (210) is also provided for distributing fluid from multiple conduits to a single conduit.

Description

HEAT EXCHANGER APPARATUS AND METHODS FOR CONTROLLING THE TEMPERATURE OF A HIGH PURITY, RE-CIRCULATING LIQUID

Technical Field

[0001] The present invention relates generally to the field of cooling and heating fluids. More particularly, the present invention relates to cooling and heating fluids in fluid recirculation loops, such as those used in the manufacture of semiconductor wafers, which require the avoidance or at least minimization of impurities being introduced into the fluid in the recirculation loop.

Brief Description of the Drawings

[0002] Understanding that drawings depict only typical embodiments of the invention and are not therefore to be considered to be limiting of its scope, the invention will be described and explained with additional specificity and detail through the use of the accompanying drawings. The drawings are listed below. [0003] FIG. 1 is a schematic view of a method and system for heat transfer and temperature control of a process liquid wherein the heat exchanger apparatus has two gas separators adapted to separate pressurized gas into gas streams having different temperatures.

[0004] FIG. 2A is a perspective view of the housing of the heat exchanger apparatus with an inlet manifold fitting and an outlet manifold fitting extending through one of the end caps.

[0005] FIG. 2B is a perspective view of the same housing shown in FIG. 2A with complete inlet and outlet fittings. [0006] FIG. 2C is a perspective view of the heat exchanger apparatus with a partial cut-away view of the housing.

[0007] FIG. 3A is an exploded perspective view of the components of the heat exchanger apparatus.

[0008] FIG. 3B an enlarged perspective view of the gas separator case and an exploded perspective view of the components of the gas separator for delivery of a stream of cold gas and the gas separator for delivery of a stream of cold gas.

[0009] FIG. 3C an exploded perspective view of the components shown in FIG. 3B from another viewing angle.

[001O] FIG. 3D is an enlarged perspective view of a vortex generator.

[0011] FIG. 3E is an enlarged perspective view of a stream decoupler.

[0012] FIG. 4A is a perspective view of the side of the heat exchanger apparatus shown in FIG. 2B.

[0013] FIG. 4B is a cross-sectional view of the heat exchanger apparatus taken along cutting line 4B — 4B in FIG. 4A.

[0014] FIG. 4C is a cross-sectional view of the heat exchanger apparatus taken along cutting line 4C — 4C in FIG. 4A.

[0015] FIG. 5 is an exploded perspective view of the inlet fitting for the fluid which flows into the heat exchanger apparatus for heat transfer.

[0016] FIG. 6A depicts the heat exchange tubes after being positioned within the passages of the body of a manifold fitting such that they extend beyond the first end of the body.

[0017] FIG. 6B depicts tubes 140 have been cut off to be as close as possible to being flush with the face of the body of the manifold fitting. [0018] FIG. 6C depicts an infrared heater exposing the inlet ends of the tubes and the portion of the body of the manifold fitting under its face to fuse the tubes and the body at least under its face.

[0019] FIG. 6D is a perspective view of the body of the manifold fitting and the spacing around the inlet ends of the heat transfer tubes before the inlet ends and the body are fused.

[002O] FIG. 6E is a cross-sectional view of the body of the manifold fitting and the spacing around the inlet ends of the heat transfer tubes before the inlet ends and the body are fused.

[0021] FIG. 6F depicts the inlet ends of heat transfer tubes before being fused to the body of the manifold fitting.

[0022] FIG. 6G depicts the inlet ends of heat transfer tubes after being fused to the body of the manifold fitting.

[0023] FIG. 7 is a schematic view of a method and system for heat transfer and temperature control of a process liquid wherein the heat exchanger apparatus has one gas separator adapted to separate pressurized gas into gas streams having different temperatures.

[0024] FIG. 8 is an exploded perspective view of the components of a heat exchanger apparatus having one gas separator adapted to separate pressurized gas into gas streams having different temperatures.

[0025] FIG. 9A is a perspective view of the side of the heat exchanger apparatus shown in FIG. 7.

[0026] FIG. 9B is a cross-sectional view of the heat exchanger apparatus taken along cutting line 9B— 9B in FIG. 9A. [0027] FIG. 10A is a schematic view of another method and system for heat transfer and temperature control of a process liquid wherein the heat exchanger apparatus has one gas separator adapted to separate pressurized gas into gas streams having different temperatures and a hot gas passage which receives heated gas from an electric heater.

[0028] FIG. 10B is a cross-sectional view of the heat exchanger apparatus taken along cutting line 10B— 10B in FIG. 10A.

[0029] FIG. 11A is a schematic view of an additional method and system for heat transfer and temperature control of a process fluid wherein the heat exchanger apparatus has a fluid passage component. A case is also shown which has a pair of gas separators in fluid communication with the heat transfer tubes.

[003O] FIG. 11 B is a perspective view of the heat exchanger apparatus taken along cutting line 11 B — 11 B in FIG. 11 A.

[0031] FIG. 11C is a perspective view of the housing of the heat exchanger apparatus shown in FIG. 11 B with an inlet manifold fitting and an outlet manifold fitting extending through one of the end caps via manifold fitting receptacles. The other end cap is shown with an inlet fitting and an outlet fitting.

[0032] FIG. 11 D is a cross-sectional view of the heat exchanger apparatus taken along cutting line 11 D— 11 D in FIG. 11 C.

[0033] FIG. 11 E is a perspective view of the case containing two gas separators.

[0034] FIG. 11 F is a cut-away view of the case and the two gas separators taken along cutting line 11 F— 11 F in FIG. 11 E.

[0035] FIG. 12A is a schematic view of another method and system for heat transfer and temperature control of a process liquid. The heat exchanger apparatus has a housing around a liquid passage component and heat transfer tubes around the liquid passage component. A case is also shown which has a pair of gas separators in fluid communication with the heat transfer tubes.

[0036] FIG. 12B is a perspective view and partial cut-away of the heat exchanger apparatus and a perspective view of the case shown in FIG. 12A.

[0037] FIG. 13 is a schematic view of yet another method and system for heat transfer and temperature control of a process liquid.

[0038] FIG. 14 is a perspective view of a tube 140 (without combs) which is wound from one end of fluid directional component (not shown) and then back to the same end.

Index of Elements Identified in the Drawings

[0039] Elements shown in one or more of or discussed with reference to FIGS. 1 , 7, 10A, 11A, 12A and 13:

10 process tank

20 recirculation pump

30 optional component

35 bypass line

60 controller

62 temperature sensor

70 compressed gas source

72 first valve for gas delivery

74 second valve for gas delivery

[0040] Elements shown in one or more of or discussed with reference to FIGS. 1 , 2A- 2C, 3A, 4A-4C, and 9A-9B, 10A-10B, 11A-11D, and 14:

100 heat exchanger apparatus 110 housing

112 shell

120 end cap

122 access portal

124 exhaust vent

130 end cap

132 inlet opening

134 outlet opening

140 heat transfer tubes

142i inlet ends of heat transfer tubes 140

142o outlet ends of heat transfer tubes 140

150 tube support combs

152 comb holes

160 baffle

162 baffle holes

164 baffle access

[0041] Elements shown in one or more of or discussed with reference to FIGS. 2A- 2C, 3A, 5, 6A-6G and 8, 9A-9B, 10B, 11 B-11D, 13 and 14:

20Oi inlet fitting

20Oo outlet fitting

204i anchorable inlet manifold fitting

204o anchorable outlet manifold fitting

205i connected inlet manifold fitting

205o connected outlet manifold fitting

206i extension of inlet manifold fitting 206o extension of outlet manifold fitting

21Oi inlet manifold fitting

21Oo outlet manifold fitting

212i first end of body 22Oi

212o first end of body 22Oo

214i second end of body 22Oi

214o second end of body 22Oo

216i passages

216o passages

217i terminal portion of passage 216i

218i face at the first end of body 22Oi

218o face at the first end of body 22Oo

22Oi body of inlet manifold fitting

22Oo body of outlet manifold fitting

222i seal interface of body 22Oi

222o seal interface of body 22Oo

224i track of body 22Oi

224o track of body 22Oo

226i groove of body 22Oi

226o groove of body 22Oo

24Oi manifold fitting receptacle

24Oo manifold fitting receptacle

242i threads of manifold fitting receptacle 24Oi

242o threads of manifold fitting receptacle 24Oo

244i sleeve portion of manifold fitting receptacle 24Oi 244o sleeve portion of manifold fitting receptacle 24Oo

25Oi fitting nut

25Oo fitting nut

252i threads of fitting nut 25Oi

252o threads (not shown) of fitting nut 25Oo

26Oi fluid communicator

260o fluid communicator

262i conduit of fluid communicator 26Oi

263i flared end of neck 264i of fluid communicator 26Oi

263o flared end of neck 264o of fluid communicator 26Oo

264i neck of fluid communicator 26Oi

264o neck of fluid communicator 26Oo

266i elbow of fluid communicator 26Oi 266o elbow of fluid communicator 26Oo 268i neck of fluid communicator 26Oi

268o neck of fluid communicator 26Oo 269i threads 269o threads 27Oi fitting nut 27Oo fitting nut

299 infrared heater

[0042] Elements shown in one or more of or discussed with reference to FIGS. 1 , 2C, 3A-3E, 4A-4C, 8 and 9A-9B, 1OB, 11A-11 B, 11 E-11 F and 12A-12B:

300 gas separator case

302 exhaust end of gas separator case 304 delivery end of gas separator case

306 grooves

308 baffle rim of gas separator case 300

322 gas inlets

326 gas channels

328 gas channel extension

332 exhaust portal for gas separators 400c and 40Oh

334 delivery portals

342c access portal for gas separator 400c

342h access portal for gas separator 400c

360c cold gas stream chamber

36Oh hot gas stream chamber

370 delivery chamber

[0043] Elements shown in one or more of or discussed with reference to FIGS. 3A- 3E, 4A-4C, 8, 9A-9B, 11 E-11 F, and 12A-12B:

400 hot gas passage

400c gas separator for delivery of stream of cold gas

400h gas separator for delivery of stream of hot gas

402 gas heater

403 inlet to the hot gas passage 400

405 channel of hot gas passage 400

406 outlet to the hot gas passage 400

41 Oc flow restrictor for gas separator 400c

41 Oh flow restrictor for gas separator 40Oh

412c slot 412h slot

420c hot gas separator

42Oh hot gas separator

422c vent holes

422h vent holes

424c bands

424h bands

426c vent holes

426h vent holes

430c stream decoupler

43Oh stream decoupler

440c expansion chamber

44Oh expansion chamber

450c vortex generator

45Oh vortex generator

452c slanted tunnels

452h slanted tunnels

453c interior surface or perimeter

453h interior surface or perimeter

460c cold gas discharge nozzle

46Oh cold gas discharge nozzle

47Oh cold gas separator of gas separator 400h

472h vent holes

490 annular grooves

492 O-rings [0044] Elements shown in one or more of or discussed with reference to FIGS. 11A- 11 E and 12A-12B:

600 coupling tube

670 fitting nut

1100 heat exchanger apparatus with a liquid passage component

1110 housing

1120 end cap

1122 inlet portal

1124 outlet portal

1130 end cap

117Oi inlet fitting of the inlet portal

117Oo outlet fitting of the outlet portal

1172i fitting nut of the inlet portal

1172o fitting nut of the outlet portal

1174i channel of the inlet fitting

1174o channel of the outlet fitting

1400 fluid passage component

1403 inlet of fluid passage component 1400

1405 channel of fluid passage component 1400

1406 outlet of fluid passage component 1400 1499 weir

Detailed Description of Preferred Embodiments [0045] The inventions described hereinafter relate to a recirculation loop heat exchanger apparatus and related methods and systems. The apparatus enables the temperature of a fluid source to be controlled by heat transfer across plastic tubes that isolate the fluid source from the cooling or heating fluid. The inventions also relate to specific components as utilized with a recirculation loop heat exchanger apparatus or another apparatus.

[0046] A heat exchanger apparatus for a recirculation loop has many uses in cooling and/or heating a fluid. One example of such a use is in the manufacture of semiconductor wafers. Maintenance of the temperature of fluids used during the manufacture of semiconductor wafers is needed during many of the processing steps. Examples of such fluids used in the semiconductor manufacturing process include liquids used to etch, liquids used in photolithography processes, rinsing liquids, and cleaning fluids. Examples of etching liquids include hydrogen peroxide (H₂O₂) and acids such as hydrofluoric acid (HF) and hydrochloric acid (HCL). Examples of liquids used in photolithography processes include resist liquids and developer liquids. Slurry solutions and chemicals used in chemical-mechanical planarization (CMP). are also examples of processes that can be sensitive to small changes in temperature. Examples of rinsing liquids include deionized water and liquids used in the process known in semiconductor manufacturing industry as the RCA clean such as RCA rinsing liquids. Components used to contact such liquids are formed from materials which remain chemically inert to the liquid. [0047] The heat exchanger apparatus has a small footprint which is ideal for use in the manufacture of semiconductor wafers. Due to the costs of facilities used in the manufacture of semiconductor wafers, it is beneficial to minimize the space required for all devices utilized in the manufacturing process. [0048] In addition to controlling the temperature of the source liquid, the heat exchanger apparatus can be used to cool the source liquid from an elevated temperature in preparation for releasing into waste chemical lines. In many semiconductor fabrication facilities, waste line pipes cannot accept fluids warmer than about 50⁰C, due to the pipe material, and the chemically reactive characteristics of certain waste fluids. Accordingly, liquids, such as those mentioned above which are heated to e.g., 75°C, as is needed for efficient processing, cannot be released into waste lines, without first allowing them to cool down. Ordinarily, heated liquids are allowed to cool in a tank or reservoir within a processing unit. However, the processing unit is then not useable during the cool down interval. Consequently, manufacture of semiconductors is slowed. The heat exchanger apparatus allows this drawback to be minimized, by actively cooling the liquid, instead of storing the liquid in bulk and waiting for it to passively cool down in the tank. Specifically, the heat exchanger apparatus accelerates the rate of cooling and reduces the time required before the liquid source reaches a temperature acceptable for release into manufacturing facility waste lines. As a result, the processing unit is more readily available to process additional flat media.

[0049] In the embodiments disclosed herein of a heat exchange apparatus, a plurality of heat transfer tubes are helically wound around a fluid directional component for heat transfer. Various embodiments of a fluid directional component are disclosed including a fluid passage component, a temperature changing component, and a blocking component.

[0050] The fluid passage component and some embodiments of the temperature changing component are configured to block the flow of fluid through the center or main portion of the space defined by the heat transfer tubes while directing the flow of fluid across the tubes. Examples of a fluid passage component include tubular structures. The tubular structure may be utilized to transport a gas or a liquid. An example of a temperature changing component include at least one gas separator. Another example of a temperature changing component is an electrical gas heater. [0051]The blocking component is positioned in the housing of the heat exchanger apparatus with the heat transfer tubes positioned around the blocking structure. The blocking component does not deliver a fluid but blocks its fluid flow through the center of the coils of the heat transfer tubes or main portion of the space defined by the heat transfer tubes. An embodiment of a heat exchange apparatus utilizing a blocking component, has fluid delivered directly into the housing so that the fluid flows substantially across the heat transfer tubes from one end of the housing to the other before exiting out of the housing. Examples of blocking components include closed and hollow structures and solid structures. In one embodiment, the blocking component is rod shaped. The blocking component may have any shape which is similar or identical to those of the exterior of the fluid passage components and the temperature changing components disclosed herein. The blocking component may have any shape which substantially blocks fluid flow through the center of the coils so that the fluid is directed substantially across the heat transfer tubes from one end of the housing to the other before exiting out of the housing.

[0052] The housing of the heat exchange apparatus, the fluid directional component and the heat transfer tubes enable heat to be transferred between two fluids as one of the fluids travels around in the coils of the heat transfer tubes and the other fluid travels in a path that is essentially transverse to the coils. The fluid directional component is configured to direct fluid such that the fluid does not pass through the center of coils and instead directs the fluid from one end of the housing of the heat exchanger apparatus to the other end and across the coils of the heat transfer tubes.

For example, a fluid directional component which is a hollow tube or a gas separator receives the fluid and then directs the fluid into the space between the housing and the exterior of the fluid directional component.

[0053] FIGS. 1 , 7, 10A, 11 A, 12A and 13 provide schematic diagrams of the methods and systems used to alter and control the temperature of a process fluid, without adversely affecting the quality thereof. In one embodiment, the method comprises: sensing the temperature of the process liquid; controlling the delivery of a pressurized gas from a source of pressurized gas; changing the temperature of the pressurized gas; delivering the gas, after its temperature has been changed, to contact at least one plastic heat transfer tube; and circulating a liquid from a source of liquid such that the liquid flows and is in contact with the heat transfer tube to enable the heat transfer tube to heat or cool the liquid contacting the heat transfer tube to control the temperature of the liquid in the source. As described below, the delivery of the pressurized gas can be controlled by selectively delivering the pressurized gas or by selectively adjusting the pressure of the pressurized gas. The embodiments disclosed herein enable the temperature of a liquid in the source of liquid to be maintained in a range from about 0⁰C to about 120°C. Some embodiments permit the temperature to be in a range from about 10⁰C to about 40⁰C. Other embodiments permit the temperature to be in a range from about 15°C to about 3O⁰C.

[0054] Heat transfer tubes 140 are shown in the schematic diagrams of the methods and systems shown in and described with reference to FIGS. 1 , 7, 10A, 11 A, 12A and 13. Perspective views of heat transfer tubes 140 are shown in FIGS. 2C, 3A, 4B, 4C₁ 8, 9B, 10B, 11 D and 12B. With the exception of the embodiment shown in FIG. 12B, heat transfer tubes 140 extend helically around a fluid directional component in coils or spirals with varying diameters such that there are coils around coils. Also the coils are different distances from the exterior of the fluid directional component. Stated otherwise, the coils are ringed around each other to create offset layers around the fluid directional component. At least some of the coils are concentric with respect to some of the other coils. These coils are also in a spatial relationship which minimizes their contact with each other. The coiled configuration permits a large volume of heat transfer tubes to be positioned in a small volume of the housing. The coiled and offset configuration of the heat transfer tubes creates a tortuous path for the fluid passing around the heat transfer tubes while maximizing the surface area exposed for transferring heat between the fluids. [0055] The fluid flow is forced across the bank of helical tubes between fluid directional component and shell 112. Flow is generally across tubes and not along the length of the tubes. Enhanced heat transfer is achieved due to mixing caused by flow through the tortuous path created by array of helical tubes. [0056]A heat exchange apparatus which has heat transfer tubes helically positioned around a fluid directional component can be manufactured by various methods. For example, heat transfer tubes 140 can be manually positioned around a fluid directional component. The plurality of smaller diameter heat transfer tubes have a reduced bend radius before buckling would occur than a single larger tube with the same flow capacity. The smaller heat transfer tubes may be flexible so that they can be mechanically wound around a fluid directional component and avoid buckling due to their helical configuration within the housing of the heat exchange apparatus. Due to this flexibility, heat transfer tubes 140 may contact each other if support structures are not used to maintain transfer tubes in a particular spatial relationship. Support combs 150 are examples of support structures capable of maintaining heat transfer tubes 140 in their relative positions to other heat transfer tubes. Other support structures capable of maintaining heat transfer tubes 140 in relatively fixed positions may also be used.

[0057] In some embodiments, the heat transfer tubes are able to maintain their spatial relationship with respect to each other in between support structures and even avoid contacting each other. In other embodiments, the spatial relationship as defined by their relative positions in a support structure is maintained between two support structures in a configuration such that they do not contact each along the majority of the length between the two support structures. While the holes of the support combs are spaced apart to minimize contact between the tubes, the rigidity of the tubes also assists in their ability to avoid contacting each other as the rigidity enables the tubes to maintain their spatial relationship to adjacent tubes between support combs. When tubes are used with increased flexibility, then more support structures may be needed which are more closely positioned with respect to each other to prevent the tubes from contacting each other.

[0058] Any number of support structures such as combs 150 may be used such as one, two, three, four, five, six, etc. Also, any support structures may be used which are capable of holding the plurality of heat transfer tubes in a generally circular configuration. For example, support structures which hold each coil at three points maintains each coil in a generally circular configuration. In the embodiments depicted herein, three support combs 150 are used to maintain the coils of the plurality of heat transfer tubes in a generally circular configuration. [0059] In one embodiment, three support combs are used and each comb has 28 holes per row and 6 holes per column and 12 heat transfer tubes are wound in these holes. The heat transfer tubes may be held in the holes of such an embodiment by threading several of the tubes into an interior row of each of the combs and followed by threading several other tubes into the next outer row. Note that for simplicity, not all of the coils which can be wound around a fluid directional component, are shown. For example, in one embodiment, the number of coils is 4 times greater than the number shown.

[0060] Comb 150 may, as shown, have holes in a column which are staggered with respect to the holes of an adjacent column and similarly the holes of a row may also be staggered with respect to the holes of an adjacent row. Some tubes 140 may be threaded such that the coils are not parallel and lean with slightly different orientations or with reverse orientations. The tubes positioned in outer rows may have a substantially reverse helix angle with respect to tubes positioned in inner rows. FIG. 14 depicts a tube 140 (without combs) which is wound from one end and then back such that there is an inner helically wound set of coils and an outer helically wound set of coils. Tube 140 which is shown in FIG. 14 without other tubes to present a simplistic view depicts a first set of coils having a substantially reverse helix angle with respect to the second set of coils.

[0061] By positioning coils of heat transfer tubes such that spirals with greater diameters are positioned around coils with smaller diameters, heat transfer tubes can have long lengths while being wrapped around a fluid directional component which is much shorter. For example, in one embodiment, the length of the fluid directional component, may be about 12 inches. In one embodiment, the length of the heat transfer tubes relative to the length of the fluid directional component is about 3:1 to about 100:1. In other embodiments, it ranges from about 5:1 to about 30:1 , 10:1 to about 20:1 , and 12:1 to about 15:1. Heat transfer tubes 140 may all have the same length or tubes used in a single apparatus may have different lengths. [0062]The volume of the heat tubes relative to the volume defined by the exterior of the fluid directional component and the housing of the heat exchange apparatus may range from about 5% to about 75% in one embodiment. The space between the housing the fluid directional component is also referred to as the plenum. In other embodiments, the volume of the heat tubes relative to the volume of the plenum may range from about 10% to about 60%, from about 15% to about 50%, from about 25% to about 45%, from about 30% to about 40%, and about 35%. [0063] FIG.1 depicts an embodiment of the heat exchanger apparatus at 100 which has two temperature changing components identified at 400c and 40Oh. The temperature changing components, referred to herein as gas separators, receive pressurized gas and then change the temperature of the gas. Gas separator 400c delivers a stream of cold gas into the housing 110 of heat exchanger apparatus 100 while gas separator 40Oh delivers a stream of hot gas into housing 110. [0064] Liquid from process tank 10 flows to heat transfer tubes 140 or other heat transfer tubes via recirculation pump 20 which pressurizes the liquid. The process liquid may optionally return from heat transfer tubes 140 after passing through an optional component 30 such as a flow meter, filter, valve, etc. Liquid may also be routed through a bypass line 35 for high flow to optional component 30 from the line or the fluid communicator which delivers the pressurized liquid to heat transfer tubes 140. Alternatively, the liquid may return from the heat transfer tubes 140 to feed into the recirculating process between the process tank 10 and the recirculation pump 20. This enables high fluid flow though the bypass line 35 to be recirculated back to the liquid source. The liquid flowing through the heat exchanger apparatus mixes with the liquid flowing to the recirculation pump. The liquid source temperature can be altered and controlled by controlling the heat transferred to the liquid flow through the heat exchanger apparatus and mixing of the two liquid flows in the recirculation loop.

[0065]The temperature of process tank 10, the source of the liquid, is monitored and controlled via a controller 60 which is electronically coupled to a temperature sensor 62. Temperature sensor 62 is positioned to determine the temperature of the liquid in the process tank.

[0066] Compressed gas, such as nitrogen or air, is delivered to gas separator 400c and gas separator 40Oh in housing 110 of heat exchanger apparatus 100 from compressed gas source 70. First valve 72 controls gas delivery to gas separator 400c. Second valve 74 controls gas delivery to gas separator 40Oh. The compressed gas may be supplied to the gas separator at a flow rate of about 10 to about 35 standard cubic feet per minute (SCFM) and at a pressure of about 50 to 100 psig. For manufacturing semiconductor wafers, the compressed gas is typically supplied to the gas separator at a flow rate of about 15 SCFM and at a pressure of about 80 psig.

[0067] Apparatus 100 may be utilized to maintain a liquid in a process tank at room temperature (approximately 22°C). For such a use, apparatus 100 may be designed to adjust the temperature of the process tank or ambient bath by +/- 5°C to maintain it at approximately 22°C. Apparatus 100 may also be utilized to heat or cool the liquid beyond ambient temperature. The gas streams or fractions generated by the gas separators may have temperatures ranging from about -40⁰C to about 110⁰C. The cold gas stream generated by the gas separator may have a temperature ranging from about 28°C to about 50⁰C below the temperature of the pressurized gas received by the gas separator. The amount of heat transferred by apparatus

100 varies depending on the design. For example, it may be designed to transfer about 75 to about 300 watts. It may be designed to transfer about 120 watts for typical uses in the manufacture of semiconductor wafers.

[0068] FIG. 2A shows housing 110. Housing 110 comprises shell 112 and end caps 120 and 130. Shell 112 is the open body of housing 110. End caps 120 and 130 are at opposite ends and butt up to shell 112.

[0069] lnlet manifold fitting 21Oi and outlet manifold fitting 21Oo are shown extending through end cap 130. Inlet manifold fitting 21Oi and outlet manifold fitting 21 Oo are respectively positioned within manifold fitting receptacle 24Oi and manifold fitting receptacle 240o. FIG. 5 provides a more detailed view of inlet manifold fitting 21Oi and outlet manifold fitting 210o. A method for manufacturing such fittings is described in reference to FIGS. 6A-6G.

[0070] Each manifold fitting has a body. Body 22Oi of inlet manifold fitting 21Oi and body 22Oo of outlet manifold fitting 21Oo are formed from a plastic material as described in more detail below. Body 22Oi of inlet manifold fitting 21Oi and body 22Oo of outlet manifold fitting 21Oo respectively hold the inlet ends 142i and outlet ends 142o of heat transfer tubes 140. This configuration permits each manifold fitting to be coupled with a single fluid communicator having only one conduit such as a tube or a bulkhead. FIG. 4B and FIG. 9B show tubes 140 extending through manifold fitting receptacle 240 and positioned in manifold fitting 210. [0071]The clustering of the plurality of heat transfer tubes 140 at their ends enables a large volume of flowing fluid to be delivered from and returned to process tank 10 or another source of fluid and to then be separated into much smaller flowing volumes within housing 110 of apparatus 100. Separating the fluid into smaller flowing volumes within the separate tubes of the plurality of heat transfer tubes 140 provides for more efficient heat exchange. Tubes 140 have a large surface area, a relatively thin wall thickness, and a relatively small inner diameter. These factors enhance the ability of the fluid in tubes 140 to be heated or cooled by fluid contacting the outside of the tubes 140.

[0072] FIG. 2B shows inlet fitting 20Oi and outlet fitting 20Oo fully assembled. The same components of inlet fitting 20Oi are shown in an exploded perspective view in FIG. 8. Note that, as shown, the components of outlet fitting 20Oo and inlet fitting 20Oi may be essentially identical. As shown in FIG. 2A, manifold fitting receptacle 24Oi and manifold fitting receptacle 24Oo both have threads which are respectively identified at 242i and 242o. Threads 242i and 242o are respectively engaged by the threads 252i (shown only in FIG. 5) of fitting nut 25Oi and threads 252o (not shown) of fitting nut 25Oi. Such threads are examples of locking components. [0073] As mentioned above, the configuration of the manifold fittings permits the opposing ends of the plurality of heat transfer tubes 140 to be collectively coupled with a single fluid communicator having only one conduit such as a tube. Fluid communicator 26Oi and fluid communicator 26Oo are examples of such fluid communicators having only a single conduit. The fluid communicator may have more than one conduit. However, it is beneficial for the single conduit or multiple conduits to have a diameter or perimeter that is larger than the inner diameter or inner perimeter of tubes 240. Conduit 262i of fluid communicator 26Oi is shown in FIG. 5. FIG. 4B and FIG. 9B show the transition from manifold fitting 210 to fluid communicator 260.

[0074]The embodiments of fluid communicators depicted in FIG. 2B each comprise an elbow between necks. As shown in FIG. 5, neck 264i and neck 264o each have a flared end respectively identified at 263i and 263o. Flared ends 263i and 263o respectively seal against a seal interface 222i of body 22Oi and a seal interface 222o of body 220o. Respectively extending from the other ends of elbow 266i and 266o are necks 268i and 268o. Fitting nut 27Oi and fitting nut 27Oo are respectively positioned onto threads 269i and 269o of fluid communicator 26Oi and 26Oo to attach a tube or conduit (not shown).

[0075] FIG. 3A is an exploded perspective view of heat exchanger apparatus 100. Gas separator case 300 has an exhaust end 302 opposite from delivery end 304. Along the length of gas separator case 300 are grooves 306 which receive tube support combs 150. As shown in FIG. 2C, heat transfer tubes 140 are positioned within comb holes 152 of tube support combs 150. Support combs 150 have tabs 154 which are sized to permit them to be positioned in baffles holes 162 of baffle 160. Baffle 160 has an opening referred to as the baffle access 164 positioned around gas separator case 300 against its baffle rim 308. The configuration of baffle 160 around gas separator case 300 as it is held between support combs 150 and baffle rim 308 stabilizes support combs 150 and baffle 160.

[0076] Pressurized gas is introduced into gas separator case 300 by a compressed gas line (not shown) and into gas inlets 322c and 322h shown in FIG. 3B and FIG. 4A. The pressurized gas then flows from gas inlets 322c and 322h respectively via gas channels identified in FIG. 4B at 326c and at 326h to gas separators 400c and 40Oh. The gas channel may include an optional gas channel extension such as the extension shown at 328c in FIG. 4C.

[0077]As discussed in more detail with respect to FIGS. 3B-3E, gas separator 400c and gas separator 40Oh each receive pressurized gas and separate the pressurized gas into two gas streams. Both gas separators separate the pressurized gas they receive into a high temperature stream and a low temperature stream relative to the temperature of the pressurized gas before separation. Gas separator 400c directs a relatively cooler gas stream into housing 110 and vents the relatively hotter gas stream it generated to exhaust vent 124. Gas separator 40Oh directs a relatively hotter gas stream into housing 110 and vents the relatively cooler gas stream it generated to exhaust vent 124. This configuration enables fluid in tubes 140 to be either cooled or heated as is needed. Note that the gas separators typically operate separately as simultaneous operation would counteract their ability to alter the temperature of the fluid in the tubes. The gas stream used for heat transfer is referred to herein as the heat transfer gas stream while the other gas stream is referred to as the bypass gas stream. Since the heat transfer gas stream delivered by gas separator 400c has a low temperature relative to the temperature of the pressurized gas before separation, the letter "c" is used to indicate that its heat exchange gas stream has a relatively cooler temperature. The letter "h" is used in association with gas separator 40Oh as its heat exchange gas stream has a relatively hotter temperature.

[0078] When gas separator 4QOc delivers a relatively cooler gas stream or gas separator 40Oh delivers a relatively hotter gas stream into the space defined by housing 110 for heat transfer with the fluid in tubes 140, the gas stream is delivered at delivery end 304 of gas separator case via delivery portals 334. The other stream of gas vented by gas separator 400c (relatively hotter than the pressurized gas) or by gas separator 40Oh (relatively cooler than the pressurized gas), the bypass gas stream, is directed out of housing 100 in manner which limits its contact with the plurality of heat transfer tubes or other heat transfer tubes. Such a gas stream is directly vented via exhaust portal 332 out of gas separator case 300. As best seen in FIG. 4A, the bypass gas streams exhausted by gas separator 400c and gas separator 40Oh via exhaust portal 332 out of gas separator case 300 are vented out of heat exchanger apparatus 100 via exhaust vent 124 of end cap 120. [0079] Exhaust vent 124, shown in FIGS. 3A and 4A, is also the exit for the streams of gas which have been used for the heat transfer with the fluid in tubes 140. The heat exchange gas streams are released into housing 110 out of gas separator case 300 via delivery portals 334. After passing by tubes 140, these gas streams pass out of housing 110 via exhaust vent 124. As one of the gas separators operates, its heat exchange gas stream and its bypass gas stream recombine in housing 110 at the vent side of baffle 160 and exit exhaust vent 124. Note that exhaust vent 124 may be threaded for coupling with an external conduit to direct the discharged gas flow to a collector.

[0080] The heat exchange gas stream passes through baffle holes 162 of baffle 160 before exiting via exhaust vent 124, as best understood in reference to FIG. 3A and FIG. 4A. Baffle 160 provides uniform flow or distribution across tubes 140 so that the heat exchange. gas stream is able to uniformly contact tubes 140. Baffle 160 provides a physical barrier to enhance circulation so that the heat exchange gas stream does not immediately exit via exhaust 124. As shown in other embodiments, baffle 160 serves the same purpose with respect to liquids. Baffle 160 also allows the bypass gas stream to exit via the same vent as the heat exchange gas stream while isolating as much as possible the heat transfer tubes from the bypass stream. When the heat exchange gas stream has been released into the space defined by housing 110, its pressure has dropped significantly as compared with the pressure of the gas when delivered into the gas separator. However, as the heat exchange gas stream flows through baffle 160 and out of exhaust vent 124, it counters potential ingress of air or gas surrounding heat exchanger apparatus 100. The physical barrier of baffle 160 also further assists in minimizing the ingress of surrounding gas. [0081] FIGS. 3A-3E provide detailed views of the components of the two gas separators in gas separator case 300 which are identified as gas separator 400c and gas separator 40Oh. The general operation of the gas separators and each of their respective individual components will now be described in detail. In the discussion below, each of the components that are common to both gas separator 40Oh and gas separator 400c will be described with reference to a generic reference numeral while the same components are identified in the drawings by reference numerals which include the letter "c" or "h" to designate which gas separator the component is used with in gas separator case 300. Whenever a component in one gas separator is different from the corresponding component in the other or is not present in the other, that component will be described with reference to a specific reference numeral which includes the letter "c" or "h" to designate which gas separator the component is used with in gas separator case 300.

[0082] Gas separators 400c and 40Oh each include a flow restrictor 410, a hot gas separator 420, a stream decoupler 430, an expansion chamber 440, a vortex generator 450, and a cold gas discharge nozzle 460. Gas separator 40Oh also includes a cold gas separator 47Oh.

[0083] The compressed gas is introduced directly into vortex generator 450 via gas channel 320. Vortex generator 450 forces the pressurized gas to rotate and thereby create a vortex from the pressurized gas. As seen in FIG. 3D, vortex generator 450 has a plurality of slanted tunnels 452 that direct the gas along the interior surface or perimeter 453 of the internal bore of the device. Tunnels 452 direct gas into the bore of the gas separator at an angle that is at least approximately tangential to the interior surface 453 to initiate the rotation of the pressurized gas. [0084] The vortex is forced down the expansion chamber 440 towards the stream decoupler 430. The vortex travels down expansion chamber 440 along the inside perimeter of the chamber. Although the expansion chamber shown in the accompanying drawings is tapered such that its interior diameter increases as it approaches the stream decoupler 430, other embodiments are possible. For instance, the expansion chamber could have a uniform interior diameter or, alternatively, its interior diameter could decrease as it approaches the stream decoupler. Although stream decoupler 430 need not be present in all embodiments of gas separators, it has been found that, under certain conditions, it may be useful to include a stream decoupler to straighten out the vortex somewhat prior to venting the hot gas stream through the hot gas separator 420. Stream decoupler 430 has an opening with a plurality of projections or vanes 432, as best seen in FIG. 3E, which facilitate straightening the outer regions of the vortex.

[0085] After passing through stream decoupler 430, the now hot gas at the perimeter of the interior bore of the gas separator is vented by hot gas separator 420. Although they serve essentially the same purpose, it can be seen from the accompanying figures that hot gas separator 42Oh differs structurally from hot gas separator 420c. It should be understood, however, that some embodiments of the invention may have two gas separators, each of which have components which are identical.

[0086] Hot gas separator 42Oh has a plurality of vent holes 422h. The hot gas stream is vented through the hot gas separator 42Oh and then out through vent holes

422h. As is discussed in greater detail below, the amount of hot gas that is allowed to vent through vent holes 422h may be controlled by controlling how far flow restrictor 41Oh is threaded into hot gas separator 42Oh.

[0087] Hot gas separator 420c instead directs the hot gas through vent holes 422c that lead back towards the center of the device and outside of the interior bore. Optionally, one or more bands 424 may be disposed around the perimeter of the region to which the hot gas is directed, as shown in the accompanying figures. These bands 424 may also have vent holes 426c that are coaxial with vent holes 422c. Bands 424 may be used to provide support for a gas permeable muffling cover (not shown). Such a cover may be comprised of any suitable material which allows gas to permeate there through and may be tightly fit over bands 424 in order to reduce the noise associated with venting the hot gas.

[0088] After the hot gas stream is vented from the gas separator, the remaining gas stream is reflected off of flow restrictor 410 and travels down the center of the gas separator in the opposite direction. Flow restrictor 410 may be adjustable so as to allow the temperature and volume of the cold and hot streams of gas to be varied. In the depicted embodiment, adjustment of flow restrictor 410 may be made by screwing and unscrewing the flow restrictor 410. For example, a screwdriver may be inserted via access portal 122 of housing 100 and access portal 342c of gas separator case 300 into slot 412c. As the flow restrictor 410 is unscrewed, or threaded away from the hot gas separator 420, a greater portion of hot gas is released from the hot gas separator 420. This likewise affects the volume and temperature of cold gas released from the opposite side of the gas separator. Note that, as shown in FIG. 4A, access portal 342c for gas separator 400c is adjacent to access portal 342h for gas separator 400c [0089] As it travels down the center of the gas separator, the gas transfers heat to the gas spiraling in the other direction along the interior perimeter of the gas separator and is thereby cooled. In the depicted embodiment, the cold gas is vented through cold gas discharge nozzle 460. Cold gas discharge nozzle 460 may optionally be adapted to be fit with a vent tube to direct the cold gas to a desired location. In the depicted embodiment, cold gas discharge nozzle 460c sends the cold gas stream down a portion of gas separator case 300, including the cold gas stream chamber 360c and delivery chamber 370, and out one or more delivery portals 334 in case 300, which allows the gas stream to contact the heat transfer tubes 140. Note that delivery chamber 370 also receives hot gas from hot gas stream chamber 36Oh as the hot gas proceeds out of delivery portals 334. [009O]A gas permeable muffler (not shown) may be located in the vent tube. For example, a muffler may comprise a plastic material, such as a woven polypropylene around hot gas separator 420c or an open cell foam in delivery chamber 370. Such a device may be comprised of any suitable material which allows gas to permeate there through and reduce the noise associated with venting the cold gas. [0091] Gas separator 40Oh has an additional component — cold gas separator 47Oh — which is connected with cold gas discharge nozzle 46Oh. Cold gas separator 47Oh has vent holes 472h, which direct a cold gas stream out of the heat exchanger apparatus 100 via exhaust vent 124. Like hot gas separator 420c, cold gas separator 47Oh may have one or more bands 474h, and may also be fit with a gas permeable muffling cover (not shown) similar to that described above in connection with the hot gas separator 420c. [0092] In embodiments of the invention including two gas separators, such as the embodiment shown in FIGS. 3A-3C having gas separators 400c and 40Oh, cold gas and hot gas stream can alternatively or simultaneously be introduced into the space defined by the apparatus housing 110 and adjacent to the heat transfer tubes 140. This allows for maintenance of a liquid bath at a relatively constant temperature, within any desired range of temperatures, which is located remotely with respect to apparatus 100. In other words, when the liquid bath is at or near a temperature which is undesirably high, gas separator 400c is utilized, which introduces cold gas into the space adjacent to heat transfer tubes 140. Likewise, when the liquid bath is at or near a temperature which is undesirably low, gas separator 40Oh is utilized, which introduces hot gas into the space adjacent to heat transfer tubes 140. [0093] Of course, embodiments of the invention having only a single gas separator are also envisioned as described in reference to FIGS. 7-8 and FIGS. 9A-9B. Such embodiments may be used, for example, in environments in which it is desirable to keep a liquid bath above or below the environment temperature. For instance, if it is desired to keep a liquid bath at a temperature below the temperature of the environment, only a single gas separator is necessary to introduce cold gas into the heat transfer tubes.

[0094] Many of the fundamental aspects of the gas separators are well-known to those of skill in the art, as demonstrated by U.S. Patent Nos. 3,173,273 issued to Fulton; 4,240,261 issued to Inglis; 5,558,069 issued to Stay; 5,682,749 issued to Bristow et al.; and 6,032,724 issued to Hatta. All of the foregoing references are hereby incorporated by reference in their entirety.

[0095] Gas separators 400 may be fit within gas separator case 300, which may be configured to receive one or more gas separators. Gas separators 400 or, more particularly, one or more gas separator components, may also be configured with annular grooves 490. Each annular groove 490 may then be fit with an O-ring 492. Use of O-rings allows for creation of one or more seals to direct the gas to desired locations and/or prevent the passage of gas to undesired locations. [0096] FIG. 5 depicts inlet fitting 20Oi in an exploded perspective view. In addition to the other components of inlet fitting 20Oi, inlet manifold fitting 21Oi is best seen in FIG. 5. Inlet manifold fitting 21Oi has a body 22Oi with a first end 212i opposite from a second end 214i. Passages 216i extend from first end 212i to second end 214i. [0097] FIGS. 6A-6G depict the manufacture of inlet manifold fitting 21Oi. FIG. 6A depicts tubes 140 after being pulled through passages 216i and beyond first end 212i of inlet manifold fitting 21Oi. Note that the while the outer diameter of each tube 140 may be slightly smaller than the diameter of each passage 216i, they may also be approximately the same. Ends of tubes 140 are then cut off as shown in FIG. 6B to be as close as possible to being essentially flush with face 218i of body 22Oi. FIG. 6C depicts infrared heater 299 exposing at least a portion of body 22Oi and tubes 140 to fuse at least body 22Oi and tubes 140 at face 218i.

[0098] FIGS. 6D-6E depict an embodiment of manifold fitting 21Oi having passages 216i in its body 22Oi with terminal portions 217i which have a greater diameter at the first end 212i of body 22Oi. In some embodiments, inlet ends 142i of heat transfer tubes 140 expand upon being heated. To a less extent, in some embodiments, passages 216 of body 220 may collapse radially inward upon being heated as may the inlet ends 142 of heat transfer tubes 140 upon cooling. The spacing enables inlet ends 142i to expand radially outward during heating and to fuse with terminal portions 217i of body 22Oi. For example, in an embodiment wherein manifold fitting 21Oi and heat transfer tubes 140 are formed from polyperfluoroalkoxyethylene (PFA) and heat transfer tubes 140 have an outer diameter which is .158 inches and a wall thickness which is .02 inches, the diameter of passages 216i at first end 212i is .166 inches. In various embodiments, the diameters of the terminal portions of the channels and the inlet ends of the heat transfer tubes differ in diameter in a range of about 2% to about 10%. In other embodiments, the range is about 4% to about 6%. In yet another embodiment, the diameters differ by about 5%. [0099] FIGS. 6F-6G depict the inlet ends 142i of heat transfer tubes 140 before and after being fused to body 22Oi. As shown in FIG. 6F, tubes 140 and body 22Oi are distinct from each other at the initiation of being heated. More particularly, the outer diameter of tubes 140 are not mechanically attached to body 22Oi. After being heated, as shown in FIG. 6G, the outer diameter of tubes 140 have fused with body 22Oi such that they are mechanically attached and the complete perimeter is sealed to body 22Oi.

[00100] The objective of heating tubes 140 and the portion of body 22Oi below face 218i is to form a fluid-tight seal between the outer diameter of tubes 140 and body 22Oi so when fluid is transferred from a fluid communicator all of the fluid flows into tubes 140 and not around tubes 140 into passages 216i. When heat is applied, the circular tubes expand and engage the passages 216i. When the materials reach their melting point temperatures, the tubes 140 and body 22Oi fuse together at heated face 218i and directly below the heated face 218i. Such results are achieved primarily through the use of plastics which are either identical or are sufficiently compatible to have similar melting temperatures. Other variables include the duration of the exposure to the heating source, the temperature of the heating source, the proximity of the heat source to face 218i, and the wall thickness of tubes 140. [00101] The bodies of the manifold fittings and tubes 140 may be formed from any plastic material which remains inert to fluids such as hydrofluoric acid and other liquids used in manufacturing semiconductor wafers. Fluoropolymers are examples of suitable plastics. Specific examples of fluoropolymers which remain inert during exposure to various fluids include: polytetrafluoroethylene (PTFE) sold as Teflon, fluorinated ethylene propylene (FEP), polyperfluoroalkoxyethylene (PFA) and polyvinyl difluoride (PVDF). Other plastics which may be utilized include polypropylene (PP)₁ polyvinyl chloride (PVC), and polyvinyl difluoride (PVDF). The other components of heat exchanger apparatus 100 may also be formed from such plastics.

[00102] The plastic components are heated at or above their melting points to fuse portions of the tubes within the passages of the body of manifold fitting to the upper portion of the body of manifold fitting. Utilizing plastics which are identical or relatively similar enables the plastic components to simultaneously reach their melting points or reach them at very similar temperatures. Proper selection of such plastics ensures that one component does not receive excessive heat once it reaches its melting point as. the other component is still approaching its melting point. Avoidance of excessive heating assists in preserving the geometrical shape of the inner diameter of the tubes. Deformation of the tubes from their original geometry during heating could prevent a fluid from freely flowing through the tubes. [00103] The longer that the components are exposed to the heat then the deeper the penetration of the heat. The weld depth may be twice the thickness of the wall of the tubes to ensure that there is a secure seal. As mentioned above, the walls of tubes 140 are selected to be sufficiently thin to permit rapid and efficient heat transfer. The wall thickness is also selected to be sufficiently thick to withstand the pressure of the pressurized liquid and to prevent weeping of the fluid. For example, when the fluid is hydrofluoric acid (HF) pressurized to about 45 psi, the tube may have a wall thickness ranging from about .01 inches to about .02 inches. More particularly, a tube formed for such use from polyperfluoroalkoxyethylene may have a wall thickness of about .02 inches. To fuse such tubes to the body of a manifold fitting, an infrared heater is set at a temperature of 600⁰F and positioned about 0.5 inch away from the face of the body of the manifold fitting and the inlet ends of the tubes for about 1 minute.

[00104] The embodiment of heat exchanger apparatus 100' shown in FIGS. 7-8 and FIGS. 9A-9B which has only a single gas separator is essentially identical to the heat exchanger apparatus shown in FIGS. 1-4C. As mentioned above, embodiments with only one gas separator may be used in environments in which it is desirable to keep a liquid bath above or below the environment temperature. [00105] Like the embodiment of the heat exchanger apparatus having two gas separators, a heat exchanger apparatus having a single gas separators controls the delivery of the gas stream contacting the plurality of heat transfer tubes by: selectively enabling the gas to flow into the gas separator, selectively adjusting the pressure of the gas flowing into the gas separator, selectively adjusting the gas separator to alter the ratio of a cold or hot gas stream.

[00106] As best seen in FIG. 9A, end cap 120' has a different configuration compared with end cap 120 since there is only one gas separator in this embodiment of the heat exchanger apparatus. Flow restrictor 410c for gas separator 400c is accessed by access portal 122. The other components shown in FIG. 8 are identical to those shown in FIG. 3A. As discussed below with reference to FIG. 9B, the internal configuration of gas separator case 300' differs from gas separator case 300. [00107] FIG. 9B shows the same view of apparatus 100' as is shown of apparatus 100 in FIG. 4C. Since gas separator 300c is the only gas separator in gas separator case 300', it is centered differently from separator 300c within gas separator case 300. Another difference is that there is not a delivery chamber as the cold gas stream chamber 360c directly delivers the cold gas stream out of delivery portals 334.

[00108] FIG. 10A depicts a schematic view of a method and system for heat transfer and temperature control of a process liquid which differs from the method and system shown in FIG. 1 by replacing gas separator 400c with a hot gas passage 400 which receives heated gas from a gas heater 402. In some embodiments, a gas heater delivers more heat than a gas separator.

[00109] Gas heater 402 is in fluid communication with hot gas passage 400. In the embodiment shown in FIG. 10A, gas heater 402 is positioned outside of heat exchanger apparatus 100". In another embodiment, the gas heater is within the heat exchanger apparatus. Any device capable of heating a pressurized gas and then transmitting the heated gas to hot gas passage 400 may be used as gas heater 402. For example, gas heater 400 may be a conventional electrical heater having a resistive element such as nichrome which defines a channel through which the pressurized gas passes. The resistive element may be separated from an outer casing formed from a material such as stainless steel by an insulator such as a ceramic. Alternatively, an electric heating element may be positioned in the hot gas passage 400 to heat the gas as it passes over the heating element and delivered to the outlet for the hot gas passage 406. An example of a heater element is Omegalux CIR-5065 sold by Omega Engineering, Inc. Those of ordinary skill in the art would recognize the need for electrical heater controls and safety devices along with needed heater mounting adaptors to position the heating element in the hot gas passage 406 and to effectively transfer and control heat to the flowing fluid. Alternatively, an electric heating element positioned around the outside of housing 110, within housing 110, or on the inside surface of housing 110 could be used to heat the fluid before and while it is flowing across the heat transfer tubes. An example of a heater element is a Kapton® insulated flexible heater part number KH- 1012/(5)-P sold by Omega Engineering, Inc. Those of ordinary skill in the art would recognize the need for electrical heater controls and safety devices along with methods to mount the heating element on or within the housing 110 of the apparatus and effectively transfer heat to the flowing fluid.

[00110] FIG. 10B depicts the tubular structure of hot gas passage 400. Hot gas passage 400 has an inlet 403 opposite from an outlet 406. FIG. 10B also shows channel 405 extending between inlet 403 and outlet 406.

[00111] FIG. 11A is a schematic view of an additional method and system for heat transfer between a fluid and a process liquid without adversely affecting the quality of the process liquid. The temperature of the process liquid is controlled by directing the process liquid through a fluid passage component 1400 which permits heat transfer with the flow of large volumes of fluids. Fluid passage component 1400 is a tube configured to receive a process liquid and to then deliver the process liquid into a heat exchanger 1100 for the exchange of heat with heat transfer tubes 140 which are wound around fluid passage component 1400. The temperature of the fluid in the heat transfer tubes is adjusted in the embodiment shown in FIG. 11 A by a pair of gas separators in fluid communication with heat transfer tubes 140 including a gas separator 400c for a cold gas stream and a hot gas separator 400h for a hot gas stream. The gas separators are contained in a case 300". [00112] FIG. 11 B depicts heat exchanger apparatus 1100 and case 300". A gas stream is delivered from one of the gas separators to heat transfer tubes 140 via a coupling tube 600 which is connected with inlet fitting 20Oi. A fitting nut 670 secures coupling tube 670 to case 300".

[00113] FIG. 11C shows end caps 1120 and 1130 heat exchanger apparatus 1100. Like end cap 130 of heat exchanger apparatus 100, end cap 1130 of heat exchanger apparatus 1100 has an inlet opening 132 and an outlet opening 134. As shown in FIG. 11 D, end cap 1120 has an inlet portal 1122 and an outlet portal 1124. Housing end caps 1120 and 1130 are welded to the shell 112 to seal the housing and withstand the process liquid pressure flowing through the heat exchanger apparatus 1100.

[00114] FIG. 11 D also shows an inlet fitting 117Oi extending through inlet portal 1122 and an outlet fitting 117Oo extending through outlet portal 1124. Each fitting 1170 has a fitting nut 1172 and a channel 1174 extending through the fitting. The fittings connect the heat exchanger apparatus 1100 to the process fluid conduits. Perspective views of fitting nuts 1172i and 1172o are shown in FIGS. 11 B-11 C. [00115] FIG. 11 D shows the pathway for a process fluid. The process fluid enters inlet 1403 of fluid passage component 1400 via channel 1174i of inlet fitting 117Oi and travels through channel 1405. The process fluid exits channel 1405 via outlet 1406 and passes out of fluid passage component 1400 and into the space defined by housing 110 around fluid passage component 1400. The fluid pressure then directs the fluid to pass across heat transfer tubes 140. Alternatively, the direction of fluid flow can be reversed. [00116] As described above, the plurality of heat transfer tubes 140 are adapted to contain a fluid and are helically wound around and along at least the majority of the length of a fluid directional component such as fluid passage component 1400 or a temperature changing component such as case 300 of gas separators or a heater. Housing 100, the fluid directional component and heat transfer tubes 140 enable heat to be transferred between the two fluids as one of the fluids travels around in the coils of the heat transfer tubes and the other fluid travels from the inlet of the fluid directional component to the outlet of the fluid directional component. The fluid passing across heat transfer tubes 140 in housing 110 travels in a direction which is essentially parallel with an axis of housing 110 or fluid directional component and essentially transverse with respect to the coils of heat transfer tubes 140. [00117] FIGS. 11 E-11 F depict gas separators 400c and 40Oh held in case 300". The components of gas separators 400c and 40Oh are identical to those of the gas separators discussed above. Case 300" also has the same components as the other cases which enclose gas separators, however, some of the components have slightly different configurations. For example, gas inlets 322c" and 322h" provide more direct pathways than gas inlets 322c and 322h. The embodiment of the case shown at 300" has only a single exhaust portal 332" and a single delivery portal 334".

[00118] FIGS. 12A-12B depict another embodiment of a method and system for heat transfer and temperature control of a process liquid. The heat exchanger apparatus 1100' comprises a housing 1110' around a liquid passage component 1400' and heat transfer tubes 140 around liquid passage component 1400'. Liquid passage component 1400' is a process tank or more particularly, a conventional overflow weir. Liquid which rises above the weir 1499' flows over weir 1499' and into housing 1110', or more particularly an outer tank. Housing 1110' has an outlet portal 1124' through which gas is expelled from outlet ends 142o of heat transfer tubes 140.

[00119] The embodiment shown in FIGS. 12A-12B has the identical case 300" and gas separators 400c and 400h as the embodiment shown and described with reference to FIGS. 11A-11 F. Like the embodiment shown and described with reference to FIGS. 11 A-11 F, a gas separator can also be replaced by a heater and a tube as described above.

[00120] FIG. 13 depicts a schematic view of another method and system for heat transfer and temperature control of a process liquid. The system involves heat transfer between two liquids and is particularly useful for higher heat transfer rates. Cold liquid source 70c and hot liquid source 7Oh are respectively delivered to fluid directional component 1400 via valves 72 and 74. In one embodiment, hot deionized water is used as hot liquid source 7Oh to transfer heat to a process liquid. The deionized water may have a temperature of about 10⁰C to about 120⁰C and be useful for adjusting the temperature of the process liquid to a temperature ranging from about 15°C to 95⁰C. For example, when 12 heat transfer tubes are used which each have a length of about 30 feet and have an outer diameter of .158" and an inner diameter of .118", deionized water having a temperature of about 90⁰C can be used as the hot liquid source to transfer heat to a process liquid having a temperature of 30⁰C such that about 6000 watts of heat is transferred. [00121] The other components in FIG. 13 are substantially identical to those which are identically numbered in the other schematic drawings. Note that the methods and systems described herein can be used for heat transfer between any two fluids including liquid/liquid, gas/liquid, liquid/gas and gas/gas. [00122] The heat transfer tubes disclosed herein are examples of heat transfer components. The heat transfer tubes are also examples of heat transfer means for receiving a pressurized fluid in the housing for heat transfer as delivered from a fluid source, providing sufficient surface area for effective heat and transfer and for delivering the fluid out of the housing to be routed back to the fluid source. [00123] The support combs are examples of support structures. Support structures are examples of means for spatially orienting the heat transfer means for effective heat transfer. The baffle is an example of means for directing the heat transfer gas stream across the heat transfer means, for minimizing contact with the heat transfer means from the bypass gas stream as the bypass gas stream is directed out of an exhaust vent, and for directing the heat transfer gas stream out of the exhaust vent after the heat transfer gas stream has contacted the heat transfer means.

[00124] As indicated above, a gas separator is an example of a temperature changing component. The gas separators are also examples of temperature changing means for receiving pressurized gas, for separating the pressurized gas into a high temperature stream and a low temperature stream relative to the temperature of the pressurized gas received, for directing one of the gas streams into contact with the plurality of heat transfer components and then out of the housing, and for directing the other stream out of the housing while limiting the contact with the heat transfer means. Such temperature changing means are also examples of means for cooling or heating the fluid in the heat transfer means. Other examples of means for heating or cooling the fluid in the heat transfer means include a hot bath or cold bath through which the heat transfer means passes. [00125] Another example of a temperature changing component is a gas heater. Some embodiments of gas heaters are examples of temperature changing means for receiving a pressurized gas, heating the gas and directing the gas into contact with the plurality of heat transfer components. The gas heaters are also examples of means for heating the fluid in the heat transfer means.

[00126] The temperature changing components are examples of fluid delivery components. Other examples of fluid delivery components include fluid passage components. Examples of fluid passages components include tubular structures. Temperature changing components and fluid passage components are examples of fluid delivery components as they are able to receive a fluid and then direct the fluid into the space between the housing and the exterior of the fluid delivery component. The fluid delivery components are examples of means for receiving a fluid into the housing and delivering the fluid into contact with the plurality of heat transfer tubes. [00127] The fluid delivery components are also fluid directional components. Other, examples of fluid directional components include blocking components. In contrast to fluid delivery components, a blocking component does not deliver a fluid is just blocks its flow through the center of the coils. An embodiment utilizing a closed, hollow, rod-shaped structure positioned along the center axis of the housing of the heat exchanger apparatus to act as a blocking component, has fluid delivered directly into the housing so that the fluid flows substantially across the heat transfer tubes from one end of the housing to the other before exiting out of the housing. [00128] A fluid directional component is positioned in the housing of the heat exchanger apparatus with the heat transfer tubes positioned around the blocking component to block the flow of fluid through the center or main portion of the space defined by the heat transfer tubes. Whether the fluid directional component is hollow like a fluid passage component, contains various structural components such as a gas separator, or is a solid blocking component, these embodiments of the fluid directional component direct fluid substantially across the coils from one end of the housing of the heat exchanger apparatus to the other end while minimizing or preventing flow through the center of the coils of the heat transfer tubes. The fluid delivery components positioned within the coils and the blocking components are examples of means for directing the fluid across the coils and minimizing or preventing flow through the center of the coils of the heat transfer tubes. [00129] The inlet manifold fittings are examples of inlet manifold means for providing fluid communication between the plurality of heat transfer means and an inlet fluid communicator having a conduit in fluid communication with the fluid source to enable the plurality of heat transfer means to receive the pressurized fluid in the housing from the fluid source. The outlet manifold fittings are examples of outlet manifold means for providing fluid communication between the plurality of heat transfer means and an outlet fluid communicator having a conduit in fluid communication with the fluid source to enable the plurality of heat transfer means to deliver the pressurized fluid out of the housing to the fluid source. [00130] All of the heat exchanger apparatus components, except the electrical heating element and associated control devices as described previously, can be constructed of non metallic materials enabling the apparatus to be exposed to the process liquids without adversely changing the operation of the heat exchanger apparatus.

[00131] Without further elaboration, it is believed that one skilled in the art can use the preceding description to utilize the invention to its fullest extent. The examples and embodiments disclosed herein are to be construed as merely illustrative and not a limitation of the scope of the present invention in any way. It will be apparent to those having skill in the art that changes may be made to the details of the above- described embodiments without departing from the underlying principles of the invention. In other words, various modifications and improvements of the embodiments specifically disclosed in the description above are within the scope of the appended claims. Note that elements recited in means-plus-function format are intended to be construed in accordance with 35 U. S. C. § 112 1J6. The scope of the invention is therefore defined by the following claims.

Claims

1. A method to alter and control the temperature of a process liquid, without adversely affecting the quality thereof, comprising: sensing the temperature of the process liquid, controlling the delivery of a pressurized gas from a source of pressurized gas, changing the temperature of the pressurized gas, delivering the gas, after its temperature has been changed, to contact at least one plastic heat transfer tube, and circulating a liquid from a source of liquid such that the liquid flows and is in contact with the heat transfer tube to enable the heat transfer tube to heat or cool the liquid contacting the heat transfer tube to control the temperature of the liquid in the source.

2. The method of claim 1 , further comprising monitoring the. temperature of the source of liquid to enable the delivery of the pressurized gas to be controlled based on input received regarding the temperature of the source of liquid.

3. The method of claim 1 , wherein the delivery of the pressurized gas is controlled by selectively delivering the pressurized gas.

4. The method of claim 1 , wherein the delivery of the pressurized gas is controlled by selectively adjusting the pressure of the pressurized gas.

5. The method of claim 1 , wherein the temperature of the pressurized gas is changed before it is delivered to the heat transfer tube as the pressurized gas passes through one of at least two temperature changing components.

6. The method of claim 5, wherein the two temperature changing components are selectively utilized to deliver pressurized gas to the heat transfer component.

7. The method of claim 1 , wherein the temperature of the pressurized gas is changed by heating the pressurized gas.

8. The method of claim 1 , wherein the temperature of the pressurized gas is changed by separating the pressurized gas into a high temperature stream and a low temperature stream relative to the temperature of the pressurized gas before separation and wherein at least one of the gas streams is then delivered to the heat transfer tube.

9. The method of claim 8, wherein the ratio of the high temperature stream and the low temperature stream is selectively adjustable.

10. The method of claim 1 , wherein the pressurized gas is delivered, after its temperature has been changed, to a plurality of heat transfer tubes.

11. The method of claim 10, wherein each of the heat transfer tubes has an inlet to receive the pressurized gas and an outlet for delivery of the pressurized gas.

12. The method of claim 10, wherein each of the heat transfer tubes is a tube having an inlet end, wherein the inlet ends are positioned in a body of an inlet manifold fitting, wherein the outlet ends are positioned in the body of an outlet manifold fitting, wherein the inlet manifold fitting is adapted to be coupled with a single fluid communicator having only one conduit.

13. The method of claim 10, wherein each of the heat transfer tubes has a wall thickness which permits the pressurized gas to be contained by each tube while transferring heat to the liquid from a higher temperature gas or from the liquid to a lower temperature gas.

14. The method of claim 1 , wherein the heat transfer tube is chemically inert to any liquid contacting the heat transfer tube.

15. The method of claim 1 , wherein the temperature of the liquid in the source of liquid is maintained via the method in a range from 0⁰C to 120⁰C.

16. An apparatus for transferring heat to a process fluid, without adversely affecting the quality thereof, the apparatus comprising: a housing having a first end and a second end, a fluid directional component situated longitudinally within the housing, a plurality of plastic heat transfer tubes adapted to contain a first fluid, wherein the plurality of heat transfer tubes are within the housing and are outside of the fluid directional component, wherein each of the heat transfer tubes has an inlet to receive the first fluid from a source outside of the housing and an outlet to deliver the first fluid out of the housing, wherein one end of each of the heat transfer tubes is fused into a fluid manifold fitting; wherein the housing, the fluid directional component and the heat transfer tubes enable heat to be transferred between the first fluid and a second fluid as the first fluid travels in the heat transfer tubes and the second fluid travels in contact with the exterior of the heat transfer tubes around the fluid directional component and within the housing.

17. The apparatus of claim 16, wherein the ends of the plurality of heat transfer tubes fused into a fluid , manifold fitting are adapted to be in fluid communication with a single fluid communicator.

18. The apparatus of claim 16, wherein said fluid manifold fitting and the ends of the plurality of heat transfer tubes have been fused together by placing the heat transfer tubes in holes in a manifold body, configuring the ends of the heat transfer tubes to be substantially flush to a face of the manifold body, and applying sufficient radiant heat to said tube ends to cause their outer walls to expand against and fuse with the walls of the holes in the manifold body to form a seal between the tubes and the manifold body.

19. The apparatus of claim 16, wherein the apparatus is configured such that the first fluid is isolated to be within the inside of the heat transfer tubes and the fluid manifold fitting and another fluid manifold fitting.

20. An apparatus for transferring heat to a process fluid, without adversely affecting the quality thereof, the apparatus comprising: a housing having a first end and a second end, a fluid directional component within the housing, a plurality of plastic heat transfer tubes adapted to contain a first fluid, wherein the plurality of heat transfer tubes are within the housing and are helically wound around the fluid directional component such that there are coils of heat transfer tubes along at least a portion of the length of the fluid directional component, wherein each of the heat transfer tubes has an inlet to receive the first fluid from a source outside of the housing and an outlet to deliver the first fluid out of the housing, and wherein the housing, the fluid directional component and the heat transfer tubes enable heat to be transferred between the first fluid and a second fluid as the first fluid travels around in the coils of the heat transfer tubes and the second fluid travels in contact with the exterior of the heat transfer tubes around the fluid directional component and within the housing.

21. The apparatus of claim 20, wherein the inlets of the heat transfer tubes are adapted to collectively receive the first fluid from a single fluid communicator.

22. The apparatus of claim 20, wherein the outlets of the heat transfer tubes are adapted to collectively deliver the first fluid to a single fluid communicator.

23. The apparatus of claim 20, wherein the coils have a plurality of diameters such that some coils are different distances from the exterior of the fluid directional component.

24. The apparatus of claim 20, wherein the coils are wrapped around each other in an offset configuration.

25. The apparatus of claim 20, wherein the heat transfer tubes are flexible enough to avoid buckling due to their helical configuration within the housing.

26. The apparatus of claim 20, wherein the apparatus further comprises a plurality of tube support combs positioned within the housing, wherein the tube support combs have a plurality of holes and the tubes are positioned in the holes to enable the second fluid to flow around the tubes.

27. The apparatus of claim 20, wherein the holes are spaced apart to minimize contact between the tubes.

28. The apparatus of claim 20, wherein the plurality of heat transfer tubes are held with at least three points in each coil to maintain each coil in a generally circular configuration.

29. The apparatus of claim 20, wherein the apparatus has a length of about 12 inches.

30. The apparatus of claim 20, wherein the ratio of the length of the tubes to the length of the housing ranges from about 3:1 to about 100:1.

31. The apparatus of claim 20, wherein the volume of the space in the housing around the tubes ranges from about 5% to about 75% of the total volume between the housing and the fluid directional component.

32. The apparatus of claim 20, wherein the heat transfer tubes are chemically inert.

33. The apparatus of claim 20, wherein the fluid directional component is a temperature changing component.

34. The apparatus of claim 20, wherein the fluid directional component is a fluid passage component.

35. The apparatus of claim 20, wherein the fluid directional component is a blocking component.

36. The apparatus of claim 20, further comprising a baffle positioned in the housing.

37. An apparatus for transferring heat to a process fluid, without adversely affecting the quality thereof, the apparatus comprising: a housing having a first end and a second end, a gas delivery component within the housing, wherein the gas delivery component has an at least one inlet to receive a fluid and an outlet to deliver the gas into the housing, a plurality of heat transfer tubes adapted to contain a liquid, wherein the plurality of heat transfer tubes are within the housing and are helically wound around the gas delivery component along at least a portion of the length of the gas delivery component, wherein each of the heat transfer tubes has an inlet to receive a liquid from a source outside of the housing and an outlet to deliver the liquid out of the housing, and wherein the housing and the gas delivery component enable gas to be delivered in the housing to contact the plurality of heat transfer tubes and then to pass out of the housing.

38. An apparatus for transferring heat to a process fluid, without adversely affecting the quality thereof, the apparatus comprising: a housing having a first end and a second end, at least one temperature changing component positioned in the housing, wherein the temperature changing component has an inlet to receive pressurized fluid and an outlet to deliver the fluid into the housing, and wherein the temperature changing component changes the temperature of the fluid before the fluid is delivered into the housing, a plurality of heat transfer tubes adapted to contain a liquid, wherein the plurality of heat transfer tubes are within the housing and are helically wound around at least a portion of the length of the temperature changing component, wherein each of the heat transfer tubes has an inlet to receive a liquid from a source outside of the housing and an outlet to deliver the liquid back to the source to control the temperature of the liquid in the source, and wherein the housing and the temperature changing component direct the fluid in the housing into contact with the plurality of heat transfer tubes and then out of the housing.

39. A system for transferring heat to a process liquid, without adversely affecting the quality thereof, the system comprising: a fluid temperature changing apparatus comprising a case having an inlet and an outlet, and at least one temperature changing component within the case, wherein temperature changing component receives pressurized gas via the inlet and then changes the temperature of gas before it is delivered to the outlet; and a heat exchange apparatus comprising a housing, a fluid passage component within the housing, wherein the fluid passage component has an inlet to receive a fluid and an outlet to deliver the fluid out of the fluid passage component and into the housing, and a plurality of heat transfer tubes adapted to receive the gas from the temperature changing component, wherein the plurality of heat transfer tubes are within the housing and are helically wound around the fluid passage component such that there are coils of heat transfer tubes along at least the majority of the length of the fluid passage component, and wherein the housing, the fluid passage component and the heat transfer tubes enable heat to be transferred between the gas and the fluid as the gas travels around in the coils of the heat transfer tubes and the liquid contacts the heat transfer tubes as the liquid travels from the inlet of the fluid passage component to the outlet of the passage component.

40. A system for transferring heat to a process fluid, without adversely affecting the quality thereof, the system comprising: a fluid temperature changing apparatus comprising a case having at least one inlet and two outlets, and at least one gas separator positioned within the case, wherein the gas separator receives pressurized gas via the inlet and then separates the pressurized gas into a high temperature stream and a low temperature stream relative to the temperature of the pressurized gas received by the gas separator, wherein the gas separator is adapted to separately direct the gas streams out of the case via the outlets a heat exchange apparatus comprising a housing, at least one heat transfer tubes adapted to receive one of the gas streams from the gas separator, wherein the heat transfer tube is positioned around a liquid passage component and within the housing, and wherein the housing, the liquid passage component and the heat transfer tubes enable heat to be transferred between the gas and the liquid as the gas travels through the heat transfer tube and the liquid contacts the heat transfer tube as the liquid flows from the liquid passage component and within the housing.

41. A system for transferring heat to a process fluid, without adversely affecting the quality thereof, the system comprising: a controller; a fluid temperature changing apparatus comprising at least one gas separator, wherein the gas separator receives pressurized gas and then separates the pressurized gas into a high temperature stream and a low temperature stream relative to the temperature of the pressurized gas received by the gas separator, a heat exchange apparatus comprising at least one heat transfer tube adapted to receive one of the gas streams from the gas separator, wherein the heat transfer tube is positioned in the flow of the process liquid in a liquid passage component, and wherein the heat transfer tube enables heat to be transferred between the gas and the liquid as the gas travels through the heat transfer tubes and the liquid contacts the heat transfer tube.