U.S. patent application number 10/583904 was filed with the patent office on 2007-06-28 for potted exchange devices and methods of making.
Invention is credited to Cha P. Doh, Joseph E. Smith.
Application Number | 20070144716 10/583904 |
Document ID | / |
Family ID | 34743000 |
Filed Date | 2007-06-28 |
United States Patent
Application |
20070144716 |
Kind Code |
A1 |
Doh; Cha P. ; et
al. |
June 28, 2007 |
Potted exchange devices and methods of making
Abstract
The present invention relates to potted exchange devices
including hollow conduits and or hollow porous membranes wherein
the housing includes recessed channels or grooves. The recessed
channels or grooves are filled by the potting material during the
potting process and form a unitary end structure with the potting
material. The grooves or channels formed on the inside of the
housing maintains the integrity of the potting with the housing
under a wide range of mechanical and thermal conditions.
Inventors: |
Doh; Cha P.; (Sudbury,
MA) ; Smith; Joseph E.; (North Andover, MA) |
Correspondence
Address: |
Timothy J King;Entegris Inc
129 Concord Road
Billerica
MA
01821-4600
US
|
Family ID: |
34743000 |
Appl. No.: |
10/583904 |
Filed: |
December 21, 2004 |
PCT Filed: |
December 21, 2004 |
PCT NO: |
PCT/US04/42941 |
371 Date: |
January 16, 2007 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
60531666 |
Dec 22, 2003 |
|
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|
60586363 |
Jul 7, 2004 |
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Current U.S.
Class: |
165/158 |
Current CPC
Class: |
B01D 2311/103 20130101;
B01D 69/088 20130101; F28D 7/08 20130101; F28F 21/062 20130101;
F28D 7/082 20130101; B01D 63/02 20130101; B01D 2313/34 20130101;
F28F 1/006 20130101; F28D 21/0015 20130101; B01D 63/022 20130101;
B01D 65/003 20130101; F28F 21/067 20130101 |
Class at
Publication: |
165/158 |
International
Class: |
F28F 9/02 20060101
F28F009/02 |
Claims
1. An exchange device comprising: a thermoplastic housing having
one or more hollow conduits; said hollow conduits fluidly sealed by
a thermoplastic resin and bonded to an end portion of said housing;
the end portion of the housing having one or more grooves; said
grooves and resin forming a unitary end structure wherein the resin
and housing fuse at a portion of said groove to form said unitary
end seal.
2. The exchange device of claim 1 having a sintered thermoplastic
coating on the inside of said housing.
3. The exchange device of claim 1 wherein said housing includes
fluid fittings.
4. The exchange device of claim 1 wherein two or more grooves are
interconnected by vent channels.
5. The exchange device of claim 1 wherein said hollow conduit are
perfluorinated porous hollow fibers, perfluorinated skinned hollow
fibers, perfluorinated conduits, perfluorinated co-extruded hollow
conduits, or combinations of these.
6. The exchange device of claim 1 wherein the ends of the hollow
conduits are opened.
7. An exchange device comprising: one or more thermoplastic hollow
conduits fused at a first end portion of the conduits to a
thermoplastic resin; said thermoplastic resin fused to one or more
structures on an interior surface of a first sleeve or to a first
end of thermoplastic housing; and a second end portion of the
thermoplastic hollow conduits fused with a thermoplastic resin;
said thermoplastic resin fused to one or more structures on an
interior surface of a second sleeve or to a second end of the
thermoplastic housing.
8. The exchange device of claim 7 where the structures are
protrusions, grooves, or a combination of these.
9. The exchange device of claim 7 where the structures are grooves
in the surface of the housing or sleeves.
10. The exchange device of claim 7 having a sintered thermoplastic
coating on the inside of the sleeve or housing.
11. The exchange device of claim 7 wherein said housing or sleeve
includes fluid fittings.
12. The exchange device of claim 9 having two or more grooves in
the housing or sleeves that are interconnected by vent
channels.
13. The exchange device of claim 7 wherein the hollow conduit are
porous hollow fibers, skinned hollow fibers, thermoplastic
conduits, co-extruded hollow conduits, or combinations of
these.
14. The exchange device of claim 7 wherein the ends of the hollow
conduits are opened to fluid flow.
15. The exchange device of claim 7 wherein the thermoplastic
conduits include a perfluorinated thermoplastic.
16. An exchange device comprising: one or more co-extruded
thermoplastic hollow conduits fused at a first end portion of the
conduits to a thermoplastic resin; said thermoplastic resin fused
to a surface of a first sleeve or to a surface of a first end of
thermoplastic housing; and a second end portion of the
thermoplastic hollow conduits fused with a thermoplastic resin;
said thermoplastic resin fused to a surface of a second sleeve or
to a surface of a second end of the thermoplastic housing.
17. The exchange device of claim 16 wherein the ends of the hollow
conduits are opened to fluid flow.
18. The exchange device of claim 16 wherein said housing or sleeve
includes fluid fittings.
19. The exchange apparatus of claim 16 where the outer layer of the
co-extruded conduit includes a thermally conductive material.
20. The exchange apparatus of claim 20 where the co-extruded
conduits have an inner layer thermally bonded to an inner layers,
the outer layer fusing with a thermoplastic resin in the exchange
device.
21. A method of treating a fluid comprising: flowing a fluid to be
treated on a first side of one or more thermoplastic hollow
conduits, the hollow conduits fused at a first end portion of the
conduits to a thermoplastic resin; the thermoplastic resin fused to
one or more structures on an interior surface of a first sleeve or
to a first end of thermoplastic housing and where a second end
portion of the thermoplastic hollow conduits is fused with a
thermoplastic resin; the thermoplastic resin fused to one or more
structures on an interior surface of a second sleeve or to a second
end of the thermoplastic housing; and flowing an exchange fluid on
a second side of the thermoplastic hollow conduits to transfer
mass, energy, or a combination of these is between the first and
second fluids through a wall between the first and second side of
the hollow conduits.
22. The method of claim 21 wherein thermal energy is
transferred.
23. The method of claim 21 wherein said conduit wall is
non-porous.
24. The method of claim 21 wherein the grooves are interconnected
by vent slots.
25. An apparatus comprising: an exchange device having one or more
thermoplastic hollow conduits fused at a first end portion of the
conduits to a thermoplastic resin; said thermoplastic resin fused
to one or more structures on an interior surface of a first sleeve
or to a first end of thermoplastic housing; and a second end
portion of the thermoplastic hollow conduits fused with a
thermoplastic resin; said thermoplastic resin fused to one or more
structures on an interior surface of a second sleeve or to a second
end of the thermoplastic housing. a source of exchange fluid
connected to a first fluid inlet of the exchange apparatus and a
source of process fluid connected to a second fluid inlet of the
exchange apparatus, the first and second fluid inlets separated by
the hollow tubing, and a fluid controller fluidly connected to an
exchanger outlet in fluid communication with the second fluid
inlet, the fluid controller providing conditioned fluid to one or
more substrates to be treated by the apparatus.
26. The apparatus of claim 25 wherein the exchanger outlet in fluid
communication with the second fluid inlet provides conditioned
fluid to a tank containing one or more substrates.
27. The apparatus of claim 25 wherein the fluid controller is a
pump, a dispense pump, or a liquid flow controller.
28. The apparatus of claim 25 wherein the exchange fluid is a
source of temperature controlled fluid.
29. The apparatus of claim 25 wherein the substrate to be treated
includes silicon.
30. An exchange device comprising: potted hollow conduits in a
housing capable of transferring heat from a first fluid to a second
fluid through the walls of the hollow conduits, the exchange device
integral at a temperature of at least 100.degree. C. and a pressure
of at least 50 psig, the hollow conduits having a packing density
by volume of hollow conduits in the housing of from between 20 and
70 percent,
31. The exchange device of claim 30 with potted hollow conduits
having 9 ft.sup.2 (0.85 m.sup.2) of exchange surface area, the
exchange device capable of exchanging at least about 13,000 watts
of energy between a first fluid flowing on a first side of the
hollow conduit with a second fluid flowing on a second side of the
hollow conduits.
32. The device of claim 31 where the first fluid flows at a rate of
9.5 liter per minute or less on a first side of the hollow conduits
and the second fluid flows at a rate of 5.8 liter per minute or
less on the second side of the hollow conduits.
33. The exchange device of claim 30 where the device is integral at
a temperature of 160.degree. C. and a pressure of 70 psig.
34. The exchange device of claim 30 where the device is integral at
a temperature of 200.degree. C. and 50 psig.
35. The exchange device of claim 30 where the device includes
co-extruded perfluorinated hollow conduits.
36. The exchange device of claim 30 where the hollow conduits are
made from perfluorinated thermoplastics.
Description
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims the benefit of and priority to U.S.
Provisional Application Ser. No. 60/531,666 filed Dec. 22, 2003 and
U.S. Provisional Application Ser. No. 60/586,363 filed Jul. 7, 2004
the contents of each incorporated herein by reference in their
entirety.
BACKGROUND AND SUMMARY
[0002] Hollow fibers and thin walled hollow tubes have been used in
mass transfer, heat exchange, and cross flow particle filtration
devices. In these applications the hollow tubes or porous fibers
provide a high surface to volume ratio which permits a greater
transfer of heat and mass in a smaller volume than a device made
with flat sheet materials of similar composition.
[0003] A hollow fiber or a hollow tube includes an outer diameter
and surface, an inner diameter and surface, and a porous or
non-porous material between the first and second surfaces or sides
of the tube or fiber. The inner diameter defines the hollow portion
of the fiber or tube and is used to carry one of the fluids. For
what is termed tube side contacting, a first fluid phase flows
through the hollow portion, sometimes called the lumen, and is
maintained separate from a second fluid phase, which surrounds the
tube or fiber. In shell side contacting, the first fluid phase
surrounds the outer diameter and surface of the tube or fibers and
the second fluid phase flows through the lumen. In an exchange
apparatus, packing density relates to the number of useful hollow
fiber or hollow tubes that are available in the apparatus.
[0004] Examples of applications in semiconductor manufacturing
where heating or cooling of a liquid is used include sulfuric acid
and hydrogen peroxide photoresist strip solutions, hot phosphoric
acid for silicon nitride and aluminum metal etching solutions,
ammonium hydroxide and hydrogen peroxide SC1 cleaning solutions,
hydrochloric acid and hydrogen peroxide SC2 cleaning solutions, hot
deionized water rinses, and heated organic amine based photoresist
strippers. Mass exchange with a fluid is important where for
example particles are removed from a fluid during filtration, where
gases like ozone or hydrogen are added to water, or where dissolved
gases like oxygen are removed from fluids such as copper
electroplating solutions.
[0005] Exchange devices have been potted by preparing a shell or
housing with a thin layer of a potting material sintered to the
inside diameter surface of the shell. The device assembly,
including hollow fiber media, is then potted by surrounding the
assembly with a thermoplastic resin, and raising the temperature in
a controlled environment to melt the resin, thus filling the space
around the media at one end of the device. The resin would flow
sufficiently into the shell to encapsulate the media and adhere to
the sidewall of the shell that had been sintered with the potting
material in an earlier step. Other potting methods previously used
include: potting the device with hollow tubes outside of the shell
and machining the potted area to create a bonding surface and
thermally bonding the potted material to a housing; potting the
device with tubes outside of the shell, machining the potted area
to create a mating flange and sealing surface which could be
mechanically joined to the shell using an o-ring or other contact
sealing method--these parts could be held together by a snap ring,
threaded fasteners and or a secondary bonding operation. Additional
methods include inserting pins in each fiber, potting the assembly
and removing the pins after potting. Some exchange devices are made
by filling the lumen inside diameter with a binder and extracting
out the binder after potting and machining.
[0006] Embodiments of the present invention are exchange devices
that include a housing, shell, or sleeve bonded to one or more
thermoplastic potted hollow conduits, the housing, shell or sleeve
can includes structures such as grooves or channels on a surface of
the housing. Where grooves are present, the thermoplastic potting
material fills at least a portion of the grooves in the housing
surface and bonds to a portion of them to form a unitary end
structure with the potted hollow conduits. The unitary end
structure may then be cut open to expose the hollows of the
conduits at each potted end of the device. The structures permit
potted devices to be used at higher temperatures and pressures
while maintaining the fluid integrity of the potted device.
Exchange devices of the present invention and methods for making
them include any device that requires potting the working media
into a housing meant for containment of the process fluid including
but not limited to fully bonded membrane contactors, gas
contactors, ozone contactors, degassers, heat exchangers, heaters,
gas scrubbers, hollow fiber filters, and combinations of these. The
device can be made using thermoplastic materials, including
perfluorinated thermoplastics. Preferably the exchange device is
made from one or more perfluorinated thermoplastics.
[0007] The present invention improves the strength of such potted
devices by creating a mechanical interlock and or a fused bond
between the potting material and structures such as channels or
grooves in the housing shell. The interlock and or bond serves as a
molded in sealing surface, that has mechanical strength, preventing
separation of the mating parts. The grooves, and their additional
surface area, some of which may not be parallel to the housing
walls, result in fusion and adhesion of the potting resin to at
least a portion of the surfaces of the groove. Without wishing to
be bound by theory, it is believed that this bond can add a shear
component to the radial force created by thermal or pressure
expansion of the housing shell. This shear component is believed to
improve the strength of the device.
[0008] One embodiment of the present invention is an exchange
device that includes a thermoplastic housing having one or more
thermoplastic hollow conduits that can include hollow tubes, porous
hollow fibers, or a combination of these fluidly sealed to at least
one end of a housing or sleeve by a thermoplastic resin. The
thermoplastic resin is fluidly sealed, by fusion and or mechanical
bonds, to an end portion of the housing to one or more structures
such as protrusions, grooves, or a combination of these in the
housing. The housing structures and resin form a unitary end
structure where the resin, conduits, and housing fuse at a portion
of the housing. The unitary end structure may be machined or cut to
open the hollows of the conduits. The exchange device may have a
sintered thermoplastic coating on the inside of the housing
including the surfaces of the grooves. The exchange device housing
may include fluid fittings in fluid communication with the shell
side and fluid fittings in fluid communication with the lumen or
bore side of the device. The exchange device is made from various
thermoplastic materials, preferably the thermoplastics are
perfluoropolymers such as but not limited to FEP, PFA, MFA or a
combination of these. The exchange device may include but is not
limited to potted conduits that can be hollow tubes, porous hollow
fibers, skinned hollow fibers, thermoplastic tubes, co-extruded
hollow tubes or a combinations of these. Preferably the ends of the
potted hollow conduits are open by cutting following the potting
process. The mechanical interlock and or fusion of the potting
resin with the housing grooves serves to entrain the shell and
potted area together, particularly when stressed due to temperature
or pressure. Expansion or contraction of the housing more than the
potted material is reduced, keeping the assembly (housing, potting,
and hollow conduits) integral.
[0009] Another embodiment of the present invention is an exchange
device that includes a thermoplastic housing having one or more
fluidly sealed hollow conduits potted in a thermoplastic resin
where the thermoplastic resin occupies a volume of one or more
grooves on an interior surface of the housing. During potting, the
grooves and resin with hollow conduits form a unitary end structure
where the thermoplastic resin and housing fuse at a portion of the
groove and the resin and hollow conduits fuse to form a unitary end
structure. The housing inner surface and grooves may be coated with
a sintered thermoplastic material to which the potting resin may
fuse. The potted hollow conduits may be opened by cutting or
machining a portion of the unitary end structure to expose the
conduit lumens. Preferably the exchange device is constructed so
that fluid contacting surfaces are perfluorinated, more preferably
the exchange device is constructed of all perfluorinated
thermoplastics.
[0010] Another embodiment of the present invention is an apparatus
for exchanging energy or mass with a process fluid used to clean or
coat substrates. The apparatus can include an exchange device
having one or more thermoplastic hollow conduits fused at a first
end portion of the conduits to a thermoplastic resin. The
thermoplastic resin can be fused to an interior surface of a first
sleeve or first end of a thermoplastic housing or fused to one or
more structures on an interior surface of a first sleeve or to a
first end of thermoplastic housing. A second end portion of the
thermoplastic hollow conduits are fused with a thermoplastic resin.
The thermoplastic resin can be fused to an interior surface of a
second sleeve or second end of the thermoplastic housing or the
resin can be fused to one or more structures on an interior surface
of a second sleeve or to structures on a second end of the
thermoplastic housing. A source of working or exchange fluid is
connected to a first fluid inlet of the exchange apparatus and a
source of process fluid connected to a second fluid inlet of the
exchange apparatus. The first and second fluid inlets are separated
by the hollow tubing wall and by the potting material bonded to the
housing or sleeves. A fluid controller in fluid communication with
the second fluid inlet of the exchange device can be used to
provide controlled amounts of conditioned fluid to one or more
substrates to be treated by the apparatus. The fluid controller may
provide conditioned fluid to a tank or weir containing one or more
substrates or it may provide conditioned fluid directly to a
stationary, rotating, or translating substrate. The fluid
controller can be but is not limited to a fluid pump, a dispense
pump, or a liquid flow controller. Preferably the exchange fluid is
a source of temperature controlled fluid. Preferably the substrate
to be treated includes silicon.
[0011] Another embodiment of the present invention is an exchange
device that includes a thermoplastic housing having one or more
fluidly sealed hollow conduits potted in a thermoplastic resin. The
exchange apparatus may include one or more co-extruded
thermoplastic hollow conduits preferably has a housing or one or
more sleeve where the hollow conduits are bonded to a portion of
the housing by one or more structures such as protrusions, grooves,
or a combination of these in the housing. The resin can occupy a
volume of one or more grooves on an interior surface of the housing
and bonds to the surface. The structures, which can be grooves, and
resin form a unitary end structure with the hollow conduits where
the resin and housing fuse at a portion of the grooves or a coating
on the housing to form the unitary end seal with one or more hollow
conduits. The device may be used to treat a fluid while maintaining
the fluid integrity of the device, for example the bond between the
housing and the potting resin or hollow conduits and resin, at
temperatures below the melting point or the continuous use
temperature of the thermoplastic. This temperature may depend upon
the pressure of fluids on either side of the hollow conduit walls.
The device may be used to treat a fluid while maintaining the fluid
integrity of the device, for example the bond between the housing
and the potting resin or hollow conduits and resin at a
temperatures of at least 50.degree. C., preferably at least
140.degree. C., more preferably to 200.degree. C., and most
preferably 200.degree. C. or more but below the melting or
continuous use temperature of the thermoplastic materials.
Preferably the exchange device maintains its fluid integrity at
these temperatures when the pressure of the fluid is at least 10
psig, preferably at least 50 psig, and more preferably 70 psig or
greater. The integrity of the device can be maintained for an
exchange apparatus having a packing density of hollow conduits from
3-99 percent by volume, preferably 20-70 percent by volume and is
more preferably from 40-60 percent by volume.
[0012] Another embodiment of the present invention is a method of
making an exchange device that includes flowing a thermoplastic
material into an end portion of a housing or sleeve, the housing or
sleeve optionally having structures such as protrusions, grooves,
or a combination of these on an inner surface of the housing or
sleeve; the thermoplastic material flows between one or more hollow
conduits positioned within the housing or sleeve. Grooves in the
housing can be interconnected by other grooves or vent channels
along a surface or axis of the housing or sleeve. The method
further includes forming a fluid tight seal between the
thermoplastic material and the hollow conduits and a fluid tight
seal between the thermoplastic potting resin and the housing to
form a unitary end structure. Where grooves are used, preferably
the thermoplastic potting resin occupies at least a portion of the
grooves in the housing or sleeve and even more preferably the resin
fuses with a portion of the groove or a sintered thermoplastic
material coating the housing and groove surfaces. The hollow
portions of the conduits can be cut opened or machined to permit
fluid flow through the hollow conduits. Preferably the housing has
a coating of a thermoplastic material capable of fusing with the
potting resin on one or more of the housing surfaces.
[0013] Another embodiment of the present invention is a method of
treating a fluid that includes flowing a process fluid to be
treated on a first side of at least one hollow conduit having two
sides and a thermoplastic wall interposed between them, the hollow
conduit potted in a fluid tight manner within a thermoplastic
material. The thermoplastic potting material is bonded to housing
for the device, the housing has a thermoplastic sintered,
co-extruded, or molded to at least a portion of the inner surface,
to a portion of one or more structures, or a combination of these
on the inside surface of the housing that can fuse with the potting
resin. Where grooves are present on the housing, at least a portion
of the housing grooves are bonded to the thermoplastic material to
form a fluid tight seal between the thermoplastic material, the
hollow conduit and the housing. The method includes exchanging
energy, mass, or a combination of these with the process fluid to
be treated by flowing an exchange or working fluid on a second side
of the hollow conduits. The energy, mass, or a combination of these
is transferred to or from the process fluid to the exchange fluid
through the hollow conduit wall. The hollow conduits may be one or
more non-porous hollow tubes, skinned or unskinned porous hollow
fibers, co-extruded non-porous hollow tubes, co-extruded porous
hollow tubes, or a combination of these.
[0014] Exchange devices in embodiments of the present invention are
advantageous in that the structures such as grooves permit bonding
of the hollow conduits to the housing or sleeve and permit venting
of gases, generated or dissolved, that coalesce to form bubbles in
the thermoplastic resin melt. The thermoplastic resin, preferably a
perfluorinated thermoplastic resin melts at a temperature of
greater than about 100.degree. C. The thermoplastics used in the
present exchange devices fuse to a portion of the hollow conduits
and to the housing or grooves during the potting process. The
exchange devices of the present invention can be made from all
perfluorinated materials bonded together eliminating the need for
mechanical locking pins, silicon resins, and other
non-perflorinated polymeric bonding resins. Further, the exchangers
of the present invention eliminate the need for a reinforcing rib
bonded to the housing. Eliminating the reinforcing rib decreases
the costs of manufacture and also permits a greater number of
hollow conduits to be used in the device resulting in higher
contact surface area and packing density that improves transfer
performance and efficiency. By providing structures such as grooves
in the housing, endcap, or sleeve that the hollow conduits are
bonded with in the exchange devices of the present invention, a
wide variety of devices including immersion exchangers, weldable
zero clearance exchangers, and exchangers with one or more
different end caps can be made using readily available or readily
machined parts. Advantageously, for high purity applications,
stress relief channels in the potting resin, which can trap fluids
and contaminants are not required in exchange devices of the
present invention. This greatly simplifies the manufacturing
process and permits a greater numbers of thin walled hollow
conduits to be used in exchange devices.
DESCRIPTION OF THE DRAWINGS
[0015] In part, other aspects, features, benefits and advantages of
the embodiments of the present invention will be apparent with
regard to the following description, appended claims and
accompanying drawings where:
[0016] FIG. 1 illustrate versions of exchange devices of the
present invention for heat transfer, mass transfer or a combination
of these; (A) illustrates a housing with endcaps which has one or
more hollow conduits including hollow tubes or hollow fibers, or a
combination of these fluidly sealed to the housing by potting them
into a thermoplastic resin, the resin and hollow conduits are
initially bonded into the housing to form a unitary end structure
at each end of the housing. This unitary end structure can later be
cut to open the tubes; the thermoplastic potting material is shown
filling at least a portion of a groove or channel formed in the
housing; (B) illustrates a an exchange device having endcaps bonded
to separate housings or sleeves connected by one or more hollow
conduits bonded to a thermoplastic resin bonded to the housings;
(C) illustrates an exchange device without fluid endcaps;
[0017] FIG. 2 is an illustration of non-limiting (A) trapezoidal,
and (B) rectangular shaped grooves or channels in a housing or
sleeve wall that can add mechanical advantage, bonding, and
increased surface area to the interface between the shell and
potting; the channels may coated with a sintered thermoplastic
material for bonding and may have various shapes;
[0018] FIG. 3 is a schematic illustration of a end portion of a
housing or sleeve that includes one or more grooves or channels
with thermoplastic resin filling at least a portion of the channels
and preferably fusing to a portion of the channels and housing
surfaces; opened hollow tubes, porous hollow fibers, or a
combination of these are shown potted into the resin to form a
fluid tight seal with the housing walls and grooves; the housing
walls and grooves may have fused to their surface a powdered or
molded thermoplastic material;
[0019] FIG. 4 is an illustration of an exchange device of the
present invention, preferably with grooves in the housing and
hollow conduits potted in a thermoplastic resin, the resin bonding
with the housing walls and grooves, the exchange device is
illustrated as part of an apparatus for conditioning the
temperature of a process fluid used to clean, coat, or chemically
modify substrates in a bath or a substrate holder such as a single
wafer cleaning tool (not shown);
[0020] FIG. 5 is an illustration of one or more exchange device of
the present invention, preferably with one or more grooves in the
housing, with hollow conduits potted to each end of the housing
interior to form a fluid tight seal with a thermoplastic resin that
fuses with the housing walls, grooves, and hollow conduits; the
exchange devices are used as part of an apparatus for conditioning
a process fluid and conditioning the process fluid prior to
discharge;
[0021] FIG. 6 is an illustration of an exchange device, preferably
with one or more grooves in the housing and hollow tubes or hollow
fibers potted to form a fluid tight seal in a thermoplastic resin
which bonds or fuses with the housing walls and grooves in the
housing; the device is used as part of an apparatus for
conditioning a process fluid prior to dispense on to a substrate
which may be rotating, translating, or stationary. In this
non-limiting illustration, fluid from a fluid source which may be
for cleaning the substrate or for coating it is filtered with an
optional particle filter and energy, mass, or a combination of
these is added to the process fluid or removed from the process
fluid by the exchanger as it passes, preferably in a
counter-current manner, through the exchanger. The exchanger
transfers energy to or from the process fluid through the hollow
tube walls interacting with the exchange fluid. Temperature,
pressure and flow controllers may be used to control the amount of
fluid dispensed onto the substrate. The conditioned process,
coating, or cleaning fluid can be delivered by a pump to the
substrate which may be stationary, translating, or rotating. The
apparatus may include particle filters, valves, flow controller and
pump, or the fluid may be from a pressurized source;
[0022] FIG. 7A is an illustration of an end portion of a housing or
a end potion of a sleeve that can be used for an exchange apparatus
showing one or more parallel grooves on the inside of the shell,
the grooves illustrated having venting slots or channels
interconnecting parallel grooves; a completed exchange device
includes one or more end portions; FIG. 7B illustrates a
cross-section view of FIG. 7A; FIG. 7C illustrates an end portion
of a housing or sleeve in cross section with one or more hollow
tubes potted in a thermoplastic resin to the sleeve; FIG. 7D
illustrates an end portion of a housing or sleeve in cross section
with one or more co-extruded hollow tube fused together at an end
potion and potted in a thermoplastic resin to the sleeve;
[0023] FIG. 8 is an illustration of a test manifold that may be
used for testing an exchange apparatus for leakage, seal integrity,
and performance.
[0024] FIG. 9 is an illustration of a cross section of an end
portion of an exchange device housing or sleeve showing one or more
grooves in a portion of the wall of the housing, the depth of the
grooves in the housing wall as measured from the inner wall of the
housing, one or more of the grooves interconnected by slots or
channels in the housing wall, a powdered thermoplastic material is
shown sintered to the housing or sleeve wall;
[0025] FIG. 10 is an illustration of a cross section of an end
portion of an exchange device housing or sleeve that has one or
more parallel grooves in a portion of the wall of the housing, the
grooves having different wall heights between them and one or more
grooves or slots along an axis of the housing interconnecting the
parallel groove in the housing or sleeve wall;
[0026] FIG. 11 is an illustration of a cross section of an end of a
housing or sleeve of an exchange device with one or more parallel
grooves and one or more grooves along an axis of the housing
interconnecting adjacent parallel grooves in the housing wall, the
wall height between adjacent grooves varying along the length of
the housing; hollow conduits such as hollow tubes or fibers are
shown being potted in a heated vessel;
[0027] FIG. 12 (A) is an illustration of the cross section of a
co-extruded tube; (B) is an image of a portion of the cross section
of a co-extruded perfluorinated thermoplastic tube with an inner
PFA layer and an outer MFA layer; (C) is a full image of the cross
section of the co-extruded tube in (B); (D) is a cross section of
the co-extruded tubes in (C) potted in a thermoplastic resin and
bonded to a thermoplastic tube.
[0028] FIG. 13 (A) is an image of a portion of the cross section of
collapsed hollow tubes fused to a potting resin; (B) is an image of
a portion of the cross section of co-extruded perfluorinated tubes
potted in a perfluorinated thermoplastic sleeve; (C) is a full
image of the cross section of collapsed hollow tubes fused to a
potting resin from (A); (D) is a full image of the cross section of
co-extruded perfluorinated tubes potted in a perfluorinated
thermoplastic sleeve from (B);
[0029] FIG. 14 illustrate in cross section versions of an exchange
devices of the present invention for heat transfer; the housing
includes one or more potted hollow conduit that contain one or more
resistive filaments in the hollow, the resin and hollow conduits
are bonded to one or more grooves in the wall of the housing.
DETAILED DESCRIPTION
[0030] Before the present compositions and methods are described,
it is to be understood that this invention is not limited to the
particular molecules, compositions, methodologies or protocols
described, as these may vary. It is also to be understood that the
terminology used in the description is for the purpose of
describing the particular versions or embodiments only, and is not
intended to limit the scope of the present invention which will be
limited only by the appended claims.
[0031] It must also be noted that as used herein and in the
appended claims, the singular forms "a", "an", and "the" include
plural reference unless the context clearly dictates otherwise.
Thus, for example, reference to a "hollow tube" is a reference to
one or more hollow tubes and equivalents thereof known to those
skilled in the art, and so forth. Unless defined otherwise, all
technical and scientific terms used herein have the same meanings
as commonly understood by one of ordinary skill in the art.
Although any methods and materials similar or equivalent to those
described herein can be used in the practice or testing of
embodiments of the present invention, the preferred methods,
devices, and materials are now described. All publications
mentioned herein are incorporated by reference. Nothing herein is
to be construed as an admission that the invention is not entitled
to antedate such disclosure by virtue of prior invention.
[0032] Versions of exchange devices of the present invention can
include one or more thermoplastic hollow conduits fused or bonded
in a potting process at a first end portion of the conduits to a
thermoplastic resin. The thermoplastic resin bonded to the conduits
can be fused or bonded to the interior surface and or one or more
structures by potting on an interior surface of a first sleeve or
to structures on the first end of a thermoplastic housing. The
second end portion of the thermoplastic hollow conduits are fused
or bonded with a thermoplastic resin; the thermoplastic resin fused
to the interior surface or to one or more structures on an interior
surface of a second sleeve or to structures on a second end of the
thermoplastic housing. The hollows of the fused conduits may be
opened by cutting the resin and opening the conduit ends. The
surface on the housing or sleeves that the thermoplastic resin
bonds to can also include structures such protrusions, grooves, or
a combination of these; preferably the structures are grooves in
the surface of the housing or sleeves. The exchange device hollow
conduits can be hollow tubes, porous hollow fibers, skinned hollow
fibers, thermoplastic tubes, co-extruded hollow tubes, or
combinations of these.
[0033] Exchange devices of the present invention and methods for
making them include potting a working media, for example thin
walled hollow tubing or porous hollow fibers, into a housing or one
or more sleeves with a thermoplastic resin. The hollow tubes or
fibers potted in the housing separate through their walls a process
fluid to be conditioned from an exchange or working fluid that can
transfer mass, energy, or a combination of these with the process
fluid. Such exchange devices can include but are not limited to
fully bonded membrane contactors, gas contactors, ozone contactors,
degassers, heat exchangers, gas scrubbers, heaters, hollow fiber
filters, or combinations of these. These devices may be used to
exchange or transfer heat, mass, or a combination of these between
fluids separated by hollow thermoplastic tubes. The devices may be
immersion style or include a housing for separately containing the
process and exchange fluids.
[0034] One version of an exchange device includes one or more
co-extruded thermoplastic hollow conduits fused at a first end
portion of the conduits to a thermoplastic resin; the thermoplastic
resin fused to an interior surface of a first sleeve or to a first
end of thermoplastic housing. A second end portion of the
thermoplastic hollow conduits are fused with a thermoplastic resin,
the thermoplastic resin fused to an interior surface of a second
sleeve or to a second end of the thermoplastic housing. The ends of
the hollow conduits from the potted unitary end structure may be
opened to fluid flow by cutting or milling a portion of the
thermoplastic resin and conduits. Optionally the exchange device
housing or sleeve includes one or more fluid fittings. The
co-extruded hollow conduits may include a thermally conductive
material mixed or combined with one or more of the layers that make
up the hollow conduit. The thermoplastic housing or sleeve for the
exchange device is chosen to have a composition that permits it to
fuse with the potting resin during the potting process. It may
include housings or sleeves that are made from a thermoplastic,
thermoplastics with a sintered material on its interior surface,
co-extruded thermoplastics with one or more thermoplastic layers,
molded thermoplastics with one or more thermoplastic portions.
Preferably the housings have a thermoplastic on a portion of the
wall of the housing or sleeve in contact with the potting material
that is capable of fusing with the potting material during a
bonding process. The housing or sleeve may have a smooth surface or
it may have one or more structures formed on its inner surface to
bond with the potting resin.
[0035] A fluid-fluid phase contactor or exchange device of the
present invention may be made from thermoplastic polymeric
materials and preferably perfluorinated thermoplastic polymers. The
device can be used for contacting a fluid to be conditioned with a
working or exchange fluid. The contactor or exchange device
includes a bundle of a plurality of perfluorinated thermoplastic
hollow fiber membranes or hollow tubes 130 as for example shown in
FIG. 1A. These hollow tubes may be porous or non-porous, and each
have a first end 110 and a second end 122. The membranes and tubes
have an inner surface 109 and an outer surface 111. For hollow
membranes and hollow tubes the inner surface comprises a lumen or
bore. The hollow conduits may be selected from non-porous hollow
tubes; hollow fiber membranes having a porous skinned inner
surface, a porous outer surface, and a porous support structure
between them; hollow fiber membranes having a non-porous skinned
inner surface, a porous outer surface, and a porous support
structure between them; hollow fiber membranes having a porous
skinned outer surface, a porous inner surface, and a porous support
structure between, and hollow fiber membranes having a non-porous
skinned outer surface, a porous inner surface, and a porous support
structure between. Each end of the bundle of conduits or membranes
can be potted with a liquid tight perfluorinated thermoplastic seal
to form a unitary end structure with a surrounding perfluorinated
thermoplastic housing wherein the fiber ends are open to fluid flow
as shown by 110 and 122 in FIG. 1A. In one embodiment, the housing
124 has an inner wall with channels or grooves 104 and 116, a
portion of which are filled with the thermoplastic potting resin,
and an outer wall. The housing inner wall defines a fluid volume
between the inner housing wall and the outside 111 of the hollow
tubes or the hollow fiber membranes. The housing may have a first
fluid inlet 102 to supply a first fluid to the first end 110 of the
bundle to be contacted with a second fluid which may be supplied at
housing inlet 112. The housing may have a first fluid outlet 118
connection to remove the contacted first fluid from the second or
outlet end 122 of the hollow tubes 130. The housing fluid inlet
connection 112 can be used to supply a second fluid to be contacted
with first fluid through the walls of the hollow fibers or tubes.
The second fluid occupies the volume formed between the inner wall
of the housing 124 and the hollow fiber membranes or tubes 130. The
housing may include a second outlet 134 connection to remove the
contacted second fluid.
[0036] A method of making a fluid-fluid phase contactor
substantially made from thermoplastic polymers and preferably
perfluorinated thermoplastic polymers for contacting a first fluid
with a second fluid may include forming a bundle of a plurality of
perfluorinated thermoplastic hollow conduits such as hollow fiber
membranes, hollow tubes, or a combination of these having a first
end and a second end. The hollow conduits have an outer surface and
an inner surface, the inner membrane surface comprising a lumen or
bore. The hollow fiber membranes that can be used in the device and
the method of making it may be selected from the group consisting
of hollow fiber membranes having a porous skinned inner surface, a
porous outer surface, and a porous support structure between them;
hollow fiber membranes having a non-porous skinned inner surface, a
porous outer surface, and a porous support structure between them;
hollow fiber membranes having a porous skinned outer surface, a
porous inner surface, and a porous support structure between them;
and hollow fiber membranes having a non-porous skinned outer
surface, a porous inner surface, and a porous support structure
between. As illustrated in FIG. 11, the hollow conduits 1106 are
positioned and surrounded by an end of a perfluorinated
thermoplastic housing or a perfluorinated thermoplastic sleeve 1102
having an inner wall with channels or grooves 1112 and an outer
wall 1104. The hollow conduits 1106 are potted at each end of the
bundle positioned in the housing, of each end of the bundle potted
to a different housing sleeve (structure illustrated in FIG. 1C),
using a perfluorinated thermoplastic 1108 to form a liquid tight
perfluorinated thermoplastic seal with the ends of the hollow
conduits and to form a unitary end structure with the surrounding
perfluorinated thermoplastic housing including bonding to one or
more of the channels or grooves 1112 and 1116 with the
thermoplastic resin. Preferably after potting, the ends of the
hollow conduits are opened at both ends of the housing or ends of
separate sleeves(structure illustrated in FIG. 1C) to provide fluid
flow through the hollow conduits. The method may further include
the acts of modifying housing or one or more sleeves of the device
to provide one or more bonded endcaps, conduits, or one or more
fluid fittings. Alternatively, the device may be bonded or welded
directly into fluid flow circuit or a vessel. The device may be
used as an immersion device or in-line in a fluid flow circuit. In
a non-limiting example, the housing 124 of FIG. 1A may have a first
endcap 136 with fluid inlet 102 bonded to housing end 132 to supply
a first fluid to the first end 110 of the bundle to be contacted
with a second fluid which may be supplied at inlet 112. The housing
may have a second endcap 120 with fluid outlet connection 118
bonded to the housing end 121 to remove the contacted first fluid
from the second or outlet end 122 of the hollow conduits 130. A
housing fluid inlet connection 112, can be bonded to the housing
124 and used to supply a second fluid to be contacted with said
first fluid through the walls of the hollow conduits 130. The
second fluid occupies the volume formed between the inner wall of
the housing 124 and the hollow conduits 130. The housing may
include a second outlet 134 connection bonded to the housing 124 to
remove the contacted second fluid.
[0037] Potting and bonding of hollow conduit cords, hollow fibers
or hollow tubes, into the housing can be done in a single step
using for example a thermoplastic resin potting material such as
but not limited to Hyflon.RTM. MFA 940 AX resin, available from
Ausimont USA Inc. Thorofare, N.J. The devices can be made by
vertically placing a portion of a bundle hollow tube and or hollow
fiber cord lengths with at least one closed end, prepared for
example by wrapping the hollow tube or hollow fiber on a frame and
annealing, into a pot lifted off the bottom surface of the pot by
approximately 1/8-1/4 inch (0.318 to 0.635 cm). Thermoplastic resin
in pellet form can be placed around the outside of the shell of the
device, and the pot can be heated to melt the resin. The
temperature can be from about 270-285.degree. C. for hollow fibers,
and about 280-305.degree. C. for thin wall hollow tubes and
co-extruded hollow tubes. The resin melts and flows into the shell
and between the lumens by head pressure and capillary action. An
alternative method is to make a temporary recess made in a pool of
molten thermoplastic polymer held in a container. The hollow
conduits are held in a defined vertical position, maintaining the
thermoplastic polymer in a molten state so that it flows into the
temporary recess, around the hollow conduits and vertically up the
hollow conduits, filling the interstitial spaces between the hollow
conduits and one or more structures like grooves in the housing or
sleeve walls. A temporary recess is a recess that remains as a
recess in the molten potting material for a time sufficient to
position and fix the bundle of hollow conduits in place and then
will be filled by the molten thermoplastic The temporary nature of
the recess can be controlled by the temperature at which the
potting material is held, the temperature at which the potting
material is held during hollow conduit bundle placement, and the
physical properties of the potting material. The end of the hollow
conduits can be closed by sealing, plugging, or in a preferred
embodiment, by being formed in a loop.
[0038] While co-extruded hollow conduits, hollow tubes, and hollow
fiber having one or more layers of thermoplastic as illustrated in
FIG. 12A and shown FIG. 12C may be potted using the method
described vide supra, they may also be fused together and to a
sleeve or housing by placing a plurality of these hollow conduits
in contact with each other an approximately parallel relationship
in a housing or sleeve. A heated fluid can be introduced into the
interiors of the ends of these co-extruded hollow conduits to fuse
the lower melting outer thermoplastic layer of the conduits
together and to the housing wall to form an integrally bonded fluid
tight arrangement of the hollow conduits in the sleeve. The housing
or sleeve, optionally having structures like groove and protrusions
on its surface, may have a layer of a thermoplastic fused to its
inner surface or molded to its inner surface that can bond with the
hollow conduits. Alternatively, the fused tubes bonded together in
a first step can be potted with a thermoplastic resin in the
housing.
[0039] Another method for potting hollow tubes includes fusing a
portion of a plurality of thermoplastic hollow tubes or fibers in a
housing end or sleeve into a thermoplastic potting resin to form a
unitary end structure of the potting resin, hollow tubes, and
housing. The interior of the housing or sleeve can have one or more
fusible protrusions, one or more channels or grooves in its
surface. Alternatively, an inner layer of a co-extruded housing can
have a layer of thermoplastic that can fuse to the potting resin.
The process may involve, as illustrated in FIG. 11, placing the
assembly (housing 1102, hollow tubes 1106, and resin 1108) in a
heating cup 1136 and heating the potting resins 1108 in the heating
cup 1136 with an external heating block or other heat source until
the resin 1108, hollow tubes 1106, and housing 1102 are able to
fuse together without loss of the structure of the hollow tubes
1106. For perfluorinated thermoplastic materials, like FEP, PFA,
and MFA this can be a temperature in the range of from about
265.degree. C. to around 305.degree. C., with a preferred range of
from about 280.degree. C. to around 305.degree. C., until the melt
turns clear and is free of trapped bubbles. During heating, the
resin melt flows up and between the fibers and in the shell until
the height is equivalent or nearly equivalent on the inside of the
shell as the outside of the shell. Alternatively, a rod is inserted
into the melt to create a recess or cavity. The housing 1106 with
the grooves or channels 1112 and 1116 and the hollow tube bundle
1106 are then inserted into the cavity. At this point neither the
hollow tube bundle nor the housing touches the potting resin. The
melted resin 1108 will flow by gravity to fill the voids and
channels in the housing over time to pot the hollow tubes and bond
to the housing simultaneously. After cooling the potting process
may be repeated for the opposite end of the housing (not shown) or
another sleeve. After the potted ends are cooled, they can then be
cut and the lumen of the hollow tubes exposed. The potted ends may
be milled by a machine and bit to open the tube hollows and to form
a recessed potted region 725 away from the end portion 727 of the
housing or sleeve as illustrated in FIG. 7C. The hollow tubes 130
form a fluid tight seal 108 and 126 with the potting resin 106 and
114 respectively. The potted surfaces may be polished further using
a heat gun to melt away any smeared or rough potted surfaces. For
module with a large number of hollow tubes, such as 2000 or more,
it is possible that the module may have potting defects which can
be repaired using a clean soldering iron to fuse and close the
damaged areas, or by melting new resin into the defect with the aid
of the soldering iron.
[0040] FIG. 1A illustrates an exchange device having a housing or
sleeve with one or more grooves in the housing wall and where the
housing encloses the hollow tubes. The exchange device can have a
fluid inlet fitting 102 that is part of an endcap 136 that can be
bonded, threaded, welded, or connected by other suitable means to
the housing or sleeve 124. The housing 124 has one or more channels
or grooves, for example 104 and 116 (other grooves not shown for
clarity), in the housing or sleeve. The thermoplastic resin, for
example 106 and 114, from the potting, the hollow tubes, or a
combination of both, bonds one or more hollow tubes 130 to the
grooves 104 and 116 of the housing. As illustrated at 108 and 126
the resin 106 and 114 bonds with the hollow tubes 130 and form a
fluid tight seal with the housing grooves 104 and 116. Each hollow
tube includes an inlet 110 and an outlet 122 bonded to the housing
or sleeve 124. The housing may optionally include fluid fittings
112 and 134 that can be but are not limited to those that are
bonded, threaded, molded, or a combination of these with the
housing 124. The exchange device can have a fluid outlet fitting
118 that is part of an endcap 120 that can be bonded, threaded,
welded, or connected by other suitable methods to the housing or
sleeve 124. Hollow tubes 130 can be potted in thermoplastic resin
to form a unitary end structure and the tube ends cut to open the
lumen of the hollow tubes even with the housing end 132.
Alternatively the potting resin and hollow tubes can be machined to
sever and open the tubes and remove material from the end of the
housing or sleeve end 132 back to a position 128, and 121 back to a
position 117 This removal opens the tubes in the unitary end
structure and facilitates thermal bonding of endcaps to the housing
or sleeve 124. The hollow tubes 130 can be but are not limited to
porous hollow fibers, skinned hollow fibers, non-porous hollow
tubes, co-extruded hollow tubes or any combination of these,
preferably the tubes are thermoplastic or include a thermoplastic
material.
[0041] FIG. 1B illustrates an immersion type exchange device having
a housing enclosing the end portions of the hollow conduits 166.
The device may have an endcap 168 mounted to a housing or sleeve
148 having one or more channels or grooves 142 in the wall of the
housing or sleeve 148. The endcap can have a fluid inlet fitting
140 that may be molded, fusion bonded, threaded or otherwise
mounted to the endcap to provide a fluid inlet. Preferably the
housing 148 is or includes a thermoplastic material that can be
bonded to one or more hollow conduits 166 and bonded to
thermoplastic resin 164 in the one or more channels 142. The hollow
conduits 166 and thermoplastic resin form a fluid tight bond or
seal 146. Each hollow conduit includes an inlet 138 and an outlet
139 bonded to the housing or sleeve 148 and 158. The device may
have an endcap 156 mounted to a housing or sleeve 158 having one or
more channels or grooves 150 in the housing or sleeve. The endcap
156 can have a fluid outlet fittingl54 that may be molded, fusion
bonded, threaded or otherwise mounted to the endcap 156 to provide
a fluid outlet. Preferably the housing 158 is or includes a
thermoplastic material that can be bonded to one or more hollow
tubes 166 and bonded to thermoplastic resin 152 in the one or more
channels 150. The one or more hollow conduits 166 and thermoplastic
resin 152 form fluid tight bond or seal 162. The hollow conduits
166 can be porous hollow fibers, hollow tubes, co-extruded hollow
tubes or a combination of these that can be potted with resin to
form a fluid tight seal. Preferably the hollow tubes are
thermoplastic or contain a thermoplastic material. In FIG. 1B, the
hollow tubes 166 are illustrated as having an inner layer 144
(solid line) and an outer layer 160 (indicated by dashed line, see
also FIG. 7C and FIG. 12 A-D). For example the inner layer 144 may
represent a thermoplastic such as PFA while the outer thermoplastic
layer 160 may be a thermoplastic like MFA that can fuse with an MFA
potting resin, or FEP that is thermally bonded to inner hollow tube
layer 144. The outer layer of the co-extruded tube may only coat
those portions of the hollow tubes that are potted in the resin
(not shown), or it may coat the outsides of the hollow tubes as
illustrated. The hollow tubes 166 may be one more co-extruded
thermoplastic tubes, preferably perfluorinated thermoplastic, but
can also be but is not limited to porous or skinned thermoplastic
hollow fibers, or thermoplastic coated metals or ceramic tubular
materials.
[0042] FIG. 1C illustrates an exchange device that has a sleeve or
housing 186 that encloses a portion of the hollow conduits which
may be hollow tubes or hollow fibers. Fluid may be inlet to the
device at 170 and outlet from the device at 184. A fluid inlet
fitting or conduit may be connected to the housing 186 (see FIG.
1A), or the device can be welded into a fluid handling manifold at
inlet end 173 and outlet end 181. The housing 186 includes one or
more channels or grooves 174 and 182 that bond to the thermoplastic
resin 172 or 180. The housing may be provided with one or more
fluid inlet 178 and fluid outlet 196 connectors bonded, molded,
threaded or otherwise connected to the housingl86. The
thermoplastic resin 172 and 180 bonded to the channels 174 and 182
in the housing 186 also bonds to one or more hollow tubes 192
including but not limited to porous hollow fibers, non-porous
hollow tubes, co-extruded tubes or any combination of these. Each
hollow tube includes an inlet 190 and an outlet 194 bonded to the
housing or sleeve 186. The hollow tubes are shown bonded to the
resin, for example at 176 and 188. As shown for illustrative
purposes only, the tubing ends and potting resin may be cut back
inside the ends of the housing. Resin 172 and hollow conduits 192
may be removed by machining back to 175 and resin 180 and hollow
conduits 192 machined back to 183 to open the conduit ends. The
recessed ends can help with subsequent bonding or welding of encaps
to the housing ends 173 and 181.
[0043] FIG. 2A illustrates in cross section a non-limiting example
of channels or grooves in a portion of a housing, endcap, or sleeve
that is used to bond with hollow conduits. Such grooves include but
are not limited to rectangular grooves (B), trapazoid shaped groove
(A), and combinations of these or other shapes. The width of the
grooves, their depth, their spacing from one another, and their
spacing from the end of the housing may be varied without
limitation. FIG. 2A shows the cross section of a portion of a
cylindrical sleeve with trapazoidally shaped grooves 204 on the
inner portion of the tube. These grooves can be milled or formed
into the wall of the housing 202 to a depth 208 from inner housing
surface 210 and a distance 212 from the outer surface 216 of the
housing or sleeve. FIG. 2B illustrates rectangular grooves or
channels like groove 242. The grooves in the housing may be formed
a distance 224 from the housing or sleeve end 230. The housing end
230 can be bonded to an endcap or welded to a fluid conduit. The
grooves can be characterized by an opening illustrated by the
distance between 232 and 236. The grooves may be equally spaced,
for example 244 and 246 or 246 and 250, or the grooves may be
unequally space apart as illustrated by the larger distance between
grooves 242 and 244. The groove may have a depth 220 from the inner
surface 238 of the housing (grooves may be on the outer surface
240, not shown).
[0044] FIG. 3 illustrates the end portion of an exchange device
housing, sleeve, or endcap in cross section with one or more shaped
channels or grooves 304 in a housing, endcap, or sleeve where
different types of tubes are bonded or potted. Grooves or channels
304, which are illustrated as open trapezoids, can be any shape
that can be formed in a housing or sleeve wall 314. The sleeve wall
has an inner surface 316 and outer surface 308. The inner surface
316 may include a thermoplastic layer (not shown) that is capable
of fusing with the thermoplastic resin and one or more hollow
conduits. The surface of the one or more channels 304 is bonded to
the thermoplastic resin 310 along with one or more hollow tubes 318
and 320 in the housing 314. The thickness of the housing, sleeve,
or endcap, the distance between 308 and 316, can be chosen to meet
the pressure and temperature safety ratings of exchange device for
its intended use. In FIG. 3, 318 illustrate hollow conduits that
can be hollow tubes, porous or skinned hollow fibers, co-extruded
hollow tubes, or any combination of these potted in resin 310 to
form a fluid tight seal. In FIG. 3, 320 is an illustration of a
co-extruded hollow tube bonded to the housing 314 with
thermoplastic resin 310; 330 illustrates resin bonding adjacent
tube together. The hollow tube 320 has an inner portion or layer
with surface 322 and an outer portion or thermoplastic layer 326.
The outer layer and inner layer can both be thermoplastic
materials, preferably the outer layer 326 is a thermoplastic
capable of fusing with the thermoplastic resin and more preferably
has a lower melting point temperature than the inner layer 322. The
thermoplastics for one or more of the layers of the co-extruded
hollow conduits are preferably perfluorinated thermoplastics.
[0045] The exchange device may have a process fluid inlet and
outlet connected to the housing for receiving and delivering a
process fluid into a re-circulation loop or to a dispense tool. The
exchange device can have an exchange fluid or working fluid inlet
and outlet fittings for flow of an exchange fluid; the exchange
fluid separated from the treated fluid or process fluid by the
material in the walls of the hollow tubes and the potting bonding
the housing to the tubes. The exchange fluid exchanges or transfers
mass and or energy to or from the process fluid through the hollow
tube walls. The exchange device of the present invention may be
used in an apparatus that optionally includes a re-circulating pump
in fluid communication with the process fluid inlet on the exchange
device and optionally a tank for holding an article to be treated
by the process fluid. The exchange device may be used as part of a
dispense system or a re-circulating fluid flow circuit. The
apparatus may also further include a particle filter. The apparatus
may exchange mass and or energy with gases, organic containing
fluids, or aqueous fluids including ultra high purity water.
Preferably the substrate or article to be treated by the process
fluid includes but is not limited to metals such as copper and
aluminum, semiconductors including arsenic or silicon, or ceramics
including aluminum, barium, and strontium.
[0046] FIG. 4 illustrates an apparatus that includes an exchange
device of the present invention for conditioning a fluid used to
clean or coat substrates. The apparatus may include fluid conduits,
pumps, valves, sensors, and particle filters. For example, an
exchange fluid 450 may be directed through an exchange device 416
of the present invention by pump 446, through an optional
adjustable valve 412 and optional particle filter 408 and returned
by conduit 404 to a holding tank 448. Process fluid 428 for
cleaning or coating the substrates 434, for example a sulfuric acid
and hydrogen peroxide solution, can be pumped by fluid pump 438
through adjustable valve 442 an into exchange device 416 where
energy exchange occurs between fluid 450 and process fluid 428
through the walls of the hollow tubes in the exchanger. Conditioned
fluid exits the exchange device 416 through optional adjustable
valve 420 and optional particle filter 424 and enters the process
tank or weir 444. The process tank 444 can include a drain valve
432 to remove spent process fluid from the tank 444.
[0047] An apparatus or system for treating substrates may utilize
one or more exchange devices as illustrated in FIG. 5. The exchange
devices 516 and 544 may be configured for immersion (not shown),
co-current flow, or counter current flow. The process bath or
cleaning bath fluid 526 is treated by the exchange device 516 of
the present invention by contact through hollow tubes in the
exchange device 516 with an exchange fluid 560 which is illustrated
as being stored in a tank 556. The exchange fluid 560 may
temperature conditioned using a closed loop chiller, resistive
immersion heaters, a source of house/facilities hot or chilled
water. Alternatively the fluid may be a chemical that is generated
and fed into the exchange device for mass transfer to the process
fluid. The temperature and or chemically conditioned fluid may be
stored in the tank or feed directly to the exchange device. In FIG.
5, 504 is an exchange fluid pump that can be used to direct the
exchange fluid through an optional particle filter 508 and optional
adjustable valve 512 to the exchanger device 516. The exchange
fluid flows through the exchange device 516 and can be returned to
the tank 556 through valve 564 and conduit 554. Optionally the
exchange fluid is supplied from a facility source to exchange
device 516 and disposed of directly through conduit 554 to a drain
(not shown). Process fluid 526 from the tank 550 can be directed by
pump 548 through adjustable valve 552 through the exchange device
516 where it exchange energy, mass, or a combination of these with
the exchange fluid 560. The conditioned process fluid is removed
from the exchange device through optional valve 518 and optional
particle filter 522 and is returned to the process tank 550 for
treating the substrates 524. Waste process fluid 526 may be
disposed of through valve 540 to remove energy and or hazardous
chemicals through exchange device 544 and direct it to a waste
treatment or disposal drum through valve 532. The waste process
fluid can be treated by exchange of mass, energy, or a combination
of these with a second working fluid provided through valves 528
and 536 into the exchange device 544.
[0048] The exchange devices can also be used in a method and
apparatus for the purification of gases which may be used in
chemical processes or which may be removed from an effluent stream.
In particular, the present invention provides a device which
maintains the integrity of the potting resin and housing seal
during exothermic scrubbing reactions where for example an exhaust
fluid is purified by reacting a component of the exhaust fluid with
a reactive liquid, gel, or slurry contained on one side of a porous
hollow fiber membrane potted into a housing having grooves, the
potting and hollow conduits forming a unitary end structure with
the housing that can be cut open for fluid flow through the potted
hollow conduits.
[0049] An exchange device of the present invention may be used for
cleaning or coating of moving substrates. For example, FIG. 6
illustrates the coating or cleaning of a rotating substrate 636
with fluid from source 632 treated or conditioned by transfer of
mass, energy, or a combination of these by the exchange device 618.
An exchange or working fluid 650 from a tank 646 (or house facility
source not shown) can be made to flow through the exchange device
618 using a pump 642. The exchange fluid 650 interacts with the
process fluid 632 through the hollow tubes in the exchange device
618 and can be returned to the tank through valve 614, optional
particle filter 610 and conduit 604. Temperature conditioning or
chemical modification of the fluid 650 may be performed by
additional devices (not shown) including heaters, chillers,
chemical generators (hydrogen or ozone ) and controllers. Fluid
from source 632 can be delivered to the exchange device 618 using a
pressure source 628 or pump 638. The fluid may be treated by an
optional particle filter 622 installed upstream or downstream of
the exchange device. Valve 622 and 640 can be adjustable valves and
can be used to control flow and isolate the exchange device.
Process fluid 632 enters the exchange device and transfers mass,
energy, or a combination of these with the working fluid 650
through the hollow tube walls. The conditioned process fluid may be
dispensed to a rotating or translating substrate using pump 632,
which can be a dispense pump, dispense conduit or nozzle 630.
[0050] An example of a housing, sleeve, or portion of an endcap
with one or more channels in the inner or outer wall of the housing
is illustrated in FIG. 7(A). In FIG. 7A, a housing shell or sleeve
with venting slots 716 interconnecting the grooves or channels 720
are illustrated on inner surface of the sleeve 726. FIG. 7B
illustrates in cross section venting slots 716 interconnecting
grooves 720. The venting slots can allow for gases like air to
escape from the resin during potting. The housing can be a tube or
sleeve that encloses a portion of one or more hollow tubes and may
be pretreated by fusing a coating of a powdered thermoplastic,
co-extruding, or molding a thermoplastic to the inner wall, the
thermoplastic can be but is not limited to MFA onto the sleeve
illustrated by 936 in FIG. 9. The housing may be but is not limited
to cylindrical tubes, conduits having any number of sides including
hexagonal, rectangular or triangular conduits. The housing or
sleeve may be a thermoplastic material or may be a ceramic or
metallic tube coated with a thermoplastic material. The
thermoplastic material can be a fluorpolymer. In preferred
embodiment, the housing or sleeve includes one or more channels in
the inner or outer wall that can be bonded to the hollow tubes.
[0051] FIG. 7C illustrates in cross section an end portion of the
sleeve 726 shown in FIG. 7A and FIG. 7B. FIG. 7C illustrates one or
more hollow conduits, and in particular co-extruded hollow tubes
708 potted with a thermoplastic resin 722 in a thermoplastic or
thermoplastic coated housing or sleeve 726 having one or more
grooves 738, 740, 742, and 744 in the housing wall. The co-extruded
hollow tubes have an inner layer 704 and one or more outer layers
706 (additional layers not shown for clarity). During potting, the
outer layer 706 of the co-extruded tube fuses, mixes, or combines
with the resin to bond the hollow tubes to the resin 722 and the
housing 726. In FIG. 7C, 710 illustrates the outer layer of the
co-extruded tube and the potting resin forming an arbitrarily
defined interface separating the un-fused outer tubing layer 706
from fused resin bonded to the hollow tubes 708 and housing 726.
One or more venting grooves or slots 712 for inner groove 738, and
venting slots 716 may be formed in the housing for venting gas from
the grooves 740, 742, and 744 during potting. The surfaces of these
slots 716 may bond with the thermoplastic resin 722. During potting
one or more of the grooves 738, 740, 742, or 744 in the housing
bond with the potting resin. The number and extent that the grooves
are filled with resin may be varied by changing the amount of
thermoplastic resin in the pot and the placement of the housing in
the pot. A sufficient number of grooves are bonded to the resin to
provide strength and integrity for the intended use of the exchange
device and for bonding the hollow tubes 708 to the resin 722 and to
housing 726. This can be determined using the test apparatus of
FIG. 8 and expected application use conditions. As shown in FIG.
1A-C, each hollow tube 708 has an inlet, illustrated being
connected to 734, and outlet 724 for fluid flow. The inner layer
portion of the co-extruded tubing where outer layer 706 is still
present is shown by 728. The inner layer portion of the co-extruded
tubing where the outer layer has fused to the resin 722 is
illustrated by 736. The potting of the hollow tubes creates regions
732 between the hollow tubes above the potting resin 722 for fluid
flow contact with the outer layer of the co-extruded tubes 708.
Preferably the grooves are arranged so that their height decreases
from the groove nearest the outlet of the sleeve or housing 744 to
the groove nearest to the interior of the sleeve or housing 738.
The wall between adjacent grooves may be any shape. As shown in
FIG. 7C for illustrative purposes only, the grooves are separated
by three trapezoid shaped walls, the heights of the walls between
grooves decreasing from 742 to 738. The unitary end structure
formed during the potting process may be recessed from the end 727
of the housing or sleeve 726 to form a recessed surface 725. The
end surface 727 of the housing or sleeve can be bonded to endcaps,
fluid fittings, or welded into a fluid conduit.
[0052] FIG. 7D illustrates an end portion of an exchange device in
cross section where one or more co-extruded tubes 758 are bonded to
each other by fused resin 786 by from a portion of the
thermoplastic resin layer 756 on adjacent hollow tubes 758. The
fused hollow tube may be bonded to the thermoplastic or
thermoplastic coated housing or sleeve 770 (similar to 726) having
one or more grooves 788, 790, 792, or 794 by fusion of the housing
with the resin layer 756 on the thermoplastic hollow tubes or by
addition of a resin to form a thermoplastic 776 that bonds one or
more hollow tubes to the housing 770 and one or more grooves 788,
790, 792, or 794. The co-extruded hollow tubes have an inner layer
754 and one or more outer layers 756 (additional layers not shown
for clarity). During bonding, the outer layer 756 of the
co-extruded tube fuses, mixes, or combines with the outer layer
resin from adjacent tubes to bond the hollow tubes together 786 and
the optionally the housing 776; additional thermoplastic resin may
be used to bond one or more hollow tubes to the housing 776. In
FIG. 7D, 760 illustrates the region where the outer layer of the
bonded co-extruded tube forms an arbitrarily defined interface
separating the intact outer layer of the co-extruded tube 756 and
portion of co-extruded tubing where outer layer mixes with resin
786 or 776. One or more grooves or vent slots 766 may be formed in
the wall along an axis of the housing for venting gas from the one
or more concentrically formed grooves 788, 790, 792, or 794 during
bonding or potting. These grooves or vent slots 766 may have the
same or a different depth, size or shape than the grooves 788, 790,
792, or 794. During potting these channels can bond to the
thermoplastic resin. During bonding or potting one or more of the
grooves 788, 790, 792, or 794 in the housing can be filled with the
potting resin as shown. The number and extent that the grooves are
filled with resin may be varied by changing the amount of
thermoplastic resin in the pot and the placement of the housing in
the pot. A sufficient number of grooves 788, 790, 792, or 794 are
bonded to the resin 776 to provide strength and integrity for the
intended use of the exchange device and for bonding the hollow
tubes 758 to housing 770. As shown each hollow tube 758 has an
inlet, illustrated connected to 798, and outlet 796 for fluid flow.
The portion of the co-extruded tubing where the outer layer 756 is
still present is shown by 778, the portion of the co-extruded
tubing where the outer layer has bonded to adjacent hollow conduits
or thermoplastic resin is illustrated by 784. The un-fused regions
of the hollow tubes creates spaces 782 between the hollow tubes for
fluid flow contact with the outer layer of the co-extruded tubes.
Preferably the grooves 788, 790, 792, or 794 are arranged so that
their height decreases from the groove nearest the outlet of the
sleeve or housing 794 to the groove nearest to the interior of the
sleeve or housing 788. The wall between adjacent groove may be any
shape. As shown in FIG. 7D, for illustrative purposes only, the
groove walls are in the shape of trapezoids.
[0053] A test apparatus for measuring the integrity or performance
of an exchange device may include an exchange device, sensors, one
or more test fluids, and fluid handling devices such as pumps,
conduits, and valves. FIG. 8 illustrates a non-limiting example of
a test manifold that includes an exchange device 804 having one or
more hollow tubes bonded to a housing or sleeve having one or more
grooves. The hollow tube exchange device 804 under test, or any
portion of the manifold, may be insulated or placed in a
temperature controlled enclosure (not shown). The manifold can
include a shell fluid outlet 806 fluidly connected to an optional
sensor 808 which can be but is not limited to a pressure gauge,
temperature probe, concentration monitor, mass analyzer, flow
meter, or a combination of these. The fluid outlet and sensor may
be fluidly connected to a valve, preferably an adjustable valve
812, that is fluidly connected to the exchange device outlet 816.
The exchange device outlet 816 is in fluid communication with fluid
in the hollow lumens of the tubes that make up the exchange device.
The fluid from the outlet 816 exchanges mass, energy or a
combination of these with the fluid from source 834 through the
hollow tubes of the exchange device. The change in state of fluid
from inlet 842 as measured by sensor 850 from 854 and the state of
the fluid at outlet 816 (mass, energy, chemical composition) as
measured by sensor 808 may be used to characterize the performance
or integrity of the exchange device 804. Alternatively, the
integrity of the exchange device may be determined by examining
either the hollow tubes at 842 or 816 for fluid 834 after a period
of time under test conditions of for example pressure, temperature,
or chemical composition. For a non-porous hollow tube, an amount of
fluid 834 above that expected due to diffusion or permeation of the
material through the tube walls is an indication of loss of
integrity of the exchange device 804. An adjustable valve 820 can
be placed in fluid communication with the outside or shell side of
the hollow tubes. The valve 820 can be in fluid communication with
a sensor 822 that can be but is not limited to a pressure gauge,
temperature probe, concentration monitor, mass analyzer,
spectrophotometer, flow meter, particle counter, or a combination
of these. A fluid conditioning device 826 may be fluidly connected
to the exchange device. The fluid conditioning device can be a
chiller, heater, a gas generator with temperature monitoring and
control (not shown) or other device for conditioning a fluid 834.
For liquids, a chemically compatible pump 828 and or flow meter can
be used to deliver fluid at a know rate to the shell side of the
hollow tubes of the exchange device. Alternatively the exchange
device can be connected to a pressurized source of fluid without
flow and the temperature of the device modified during a test. An
optional sensor 832 can be fluidly connected to the test fluid
source 834, fluid source 834 can be an overflow tank. The outlet of
the shell side of the exchange device 804 may have an adjustable
valve 838 to control fluid flow through the shell side of the
device. An inlet 842 to the hollow tube lumens of the exchange
device 804 may be connected to an adjustable inlet valve 846. The
inlet valve 846 may be connected to a sensor 850 that measures the
state of a test fluid inlet to the exchange device 804 through
inlet 854 from a source (not shown). The sensor 850 may be used to
compare the inlet state of the fluid to that measured by the outlet
state measured by sensor 808 and can be used with fluid flow rate
and packing density of the hollow tubes in the exchange device to
determine the efficiency or transfer capability of the exchange
device.
[0054] The wall of a sleeve or housing with grooves and vent slots
from FIG. 7B is shown in greater detail in FIG. 9. The one or more
grooves 904, which can be paralle, are shown formed on the inside
wall of the sleeve having depth 916 in the wall as determined
between inner surface 920 and the bottom of the grooves 914. The
grooves or vent slots between grooves illustrated by 912 along an
axis of the housing interconnect adjacent grooves, provide a
bonding surface, and permit venting of gases from the thermoplastic
resin during fusion bonding or potting. The wall 908 of the
housing, sleeve, or endcap has a thickness 928 defined between
inner wall 920 and outer wall 924. The end of the housing, sleeve,
or endcap 932 may be welded, fused, or bonded to other fluid
handling devices, conduits, or vessels as shown for example in FIG.
1A The inner wall surface, groove surface, or both may be
pretreated with thermoplastic powder 936, shown as a broken white
line, that bonds to thermoplastic resin.
[0055] The wall of a sleeve or housing with grooves and vent slots
similar to FIG. 9 but with a tapered portion of the inner wall is
illustrated in FIG. 10. The one or more grooves 1004 are shown
formed on the inside wall of the sleeve having depth 1020 in the
wall 1008. The grooves or vent slots 1012 interconnect grooves
1O04. The slots permit venting of gases from the thermoplastic
resin during fusion bonding. Optional grooves 1014 may be provided
for venting from the inner most groove 1006. The inner wall 1016 of
the housing, sleeve, or endcap may be tapered, and the heights of
the groove walls 1028, 1032, and 1036 between grooves and shown as
rectangles also tapered. The height of the rectangular walls
between adjacent grooves is approximated as the distance between
groove bottom 1020 and line 1040. The taper shown gives groove wall
heights with 1036>, 1032>1028. The end of the housing,
sleeve, or endcap 1032 may be welded, fused, or bonded to other
fluid handling devices, conduits, or vessels as shown for example
in FIG. 1A. The inner wall surface, groove surface, or both may be
pretreated with thermoplastic powder (not shown for clarity). The
outer wall surface 1044 may have one or more grooves formed or
machined into its surface and into the wall 1008 (not shown).
[0056] The potting of one or more hollow conduits 1106 into a
housing having one or more grooves 1112 and 1116 and grooves or
vent slots 1132 fluidly interconnecting the adjacent grooves is
illustrated in FIG. 11. In FIG. 11, 1102 can be housing, sleeve, or
endcap with grooves 1112 and slots 1132 that hollow conduits 1106
can be potted with a thermoplastic resin illustrated as a melt by
1108. In FIG. 11, a gas bubble in the resin 1120 is illustrated as
rising through the vent slot between grooves 1116 and 1112. During
potting to form a unitary end seal the hollow conduits 11 26,
closed by frame wrapping the hollow conduits (other conduits like
1122 are also wrapped with the loop directed into the plane of the
page), are fused to the potting resin 1108, the housing, and to
each other by the heated pot 1136. The hollow conduit ends may be
opened by cutting the potting resin and conduit ends after cooling
the melt to form the unitary end structure.
[0057] FIG. 12 (A) is an illustration of the cross section of a
hollow conduit that is a co-extruded hollow tube that can be used
in the exchange devices in versions of the present invention. The
hollow tube can be but is not limited to a circular cross section,
the shape of the tube can be modified to be rectangular, a polygon,
or an ellipsoid. The tube has a thermoplastic outer layer 1204 with
a thickness shown between 1208 and 1212 and an overall outside
dimension or diameter 1216. The outer layer 1204 can have a melting
point that allows it to fuse with the potting resin but resists
change or collapse of the inner conduit layer 1228. The thickness
and uniformity of the layer may vary over the length of the tube,
however the variation permits fusion of the tubes to one another or
to a potting resin. This outer layer may include additives to
modify the exchange properties of the hollow tube. For example,
thermally conductive material such as carbon can be added to the
outer layer 1204. The hollow tube has an inner layer 1228 fused or
bonded to the outer layer with a thickness that can be measured
between 1224 and 1220 and inside diameter 1210. FIG. 12B is a
partial image of the cross section of a hollow co-extruded
perfluorinated thermoplastic tube shown in FIG. 12 C. In FIG. 12B,
the outer layer 1232 can be a perfluorinated thermoplastic like MFA
or FEP that appears as a darker layer 1232 thermally bonded to the
inner layer 1234 that can be a higher melting perfluorinated
thermoplastic like PFA. FIG. 12C illustrates the variation which
may occur in the thickness and uniformity of the outer layer. An
image of a portion of an exchange device prepared using co-extruded
tubes 1238 potted in a thermoplastic resin 1236 in a thermoplastic
sleeve or housing 1240 is shown in FIG. 12D.
[0058] FIG. 13A is the partial cross sectional image of a
cylindrical thermoplastic housing with wall 1304 and thermoplastic
hollow tubes that were potted in a sleeve without grooves at a
temperature that resulted in collapse of the thermoplastic tubes
and complete fusion of the with the thermoplastic resin 1308.
Hollow conduit collapse during bonding and poting can also occur
when variations in tube wall thickness or composition cause
variation in the melting temperature of the hollow conduits. FIG.
13 C is a full cross sectional view of FIG. 13A. FIG. 13B is a
partial cross sectional image of FIG. 13D. FIG. 13D shows one or
more opened thermoplastic co-extruded hollow conduits 1322, the
hollow conduits have an MFA outer layer and a PFA inner layer,
potted into a sleeve without grooves. FIG. 13D illustrates that the
outer MFA layer of the hollow conduit has fused with the MFA resin
1318 without collapse of the inner PFA conduit. These potted hollow
conduits 1322 were cut open to give open hollow tubes bonded in a
thermoplastic sleeve or housing 1314 under the same potting
conditions used for FIG. 13C. The higher melting temperature of the
inner layer of the hollow conduit may be used to retain the shape
of the hollow conduit and prevent collapse due to variations in
process conditions, material tolerance, and material
composition.
[0059] FIG. 14 is an illustration of an exchange device having a
housing 1416 enclosing one or more hollow conduits 1422 that are
bonded to a thermoplastic resin 1440 with one or more grooves 1404
and 1412 in the housing wall. The housing can include a shell side
fluid inlet 1408 and fluid outlet 1426 formed, bonded, threaded, or
otherwise fluidly connected to the housing 1416. One or more of the
hollow conduits can include resistive wires or filaments 1402 that
may be connected to an electrical circuit at ends represented by
1406 and 1410. The electrical circuit including a power supply and
controller (not shown). The wires 1402 in the hollow conduits 1422
may be resistively heated by the power supply and controller
whereby thermal energy is exchanged with a fluid 1432 inlet to the
device at 1408. The fluid 1432 is heated by the hollow conduit
enclosed resistive wires 1402, and can be removed from the exchange
device as heated fluid 1436 at housing fluid outlet 1426.
[0060] The exchange device may include but is not limited to one or
more potted hollow conduits that can be porous hollow fibers,
skinned hollow fibers, thermoplastic tubes, or combinations of
these bonded to a thermoplastic housing or sleeve. The exchange
device of the present invention can be made with a variety of
hollow conduits having variously shaped inner and outer surfaces
including but not limited hollow tubes, rectangular conduits,
triangular conduits. The hollow conduits generally have an outer
surface and can have one more channels along the inside of conduit.
The porosity of the hollow conduits walls can vary from non-porous
to those having a porosity suitable for filtration, liquid-liquid
contacting, and liquid-gas contacting. A fluid phase that flows
through the hollow portion of a potted hollow conduit, called the
lumen or bore for hollow tubes and hollow fibers, can transfer mass
or energy to a fluid which surrounds the outer surface of the
hollow conduit. A hollow conduit that is a porous membrane can be
described by an outer shape or dimension and an inner shape or
dimension with a porous wall thickness between them. A hollow
non-porous conduit is a conduit that can be described by an outer
shape or dimension, an inner shape or dimension, with a non-porous
wall thickness between them. For hollow tubular filaments, having
porous or non-porous walls, inner diameter defines the hollow
portion or lumen of the tube and can used to carry one of the
fluids or exchange medium.
[0061] The hollow membranes or hollow conduits may be braided or
twisted and optionally thermally annealed in a first step and then
the individual tubes separated from each other after cooling to
form self supporting helical shaped or non-circumferential shaped
single tubes. Thermal annealing sets the crests and bends of the
hollow tube so that the individual hollow tubes or cords can be
separated and handled without straightening. These shaped hollow
tube may be potted in the thermoplastic resin as described.
[0062] The outer or inner surface of a hollow fiber membrane can be
skinned or unskinned. A skin is a thin dense surface layer integral
with the substructure of the membrane. In skinned membranes, the
major portion of resistance to flow through the membrane resides in
the thin skin. The surface skin may contain pores leading to the
continuous porous structure of the substructure, or may be a
non-porous integral film-like surface. In porous skinned membranes,
permeation occurs primarily by connective flow through the pores.
Asymmetric refers to the uniformity of the pore size across the
thickness of the membrane; for hollow fiber conduits, this is the
porous wall of the fiber. Asymmetric membranes have a structure in
which the pore size is a function of location through the
cross-section, section, typically, gradually increasing in size in
traversing from one surface to the opposing surface. Another manner
of defining asymmetry is the ratio of pore sizes on one surface to
those on the opposite surface.
[0063] Manufacturers produce conduits such as pipe and thick walled
channels useful for housings, sleeves, and endcaps; hollow porous
membrane conduits; and non-porous hollow conduits from a variety of
materials, the most general class being synthetic thermoplastic
polymers. These can be flowed and molded when heated and recover
their original solid properties when cooled. As the conditions of
the application to which the hollow conduit is being used become
more severe, the materials that can be used becomes limited. For
example, the organic solvent-based solutions used for wafer coating
in the microelectronics industry will dissolve or swell and weaken
most common polymeric hollow fiber membranes or thin walled hollow
tubes. The high temperature stripping baths in the same industry
consist of highly corrosive liquids that can destroy membranes and
thin walled hollow tubes made of common polymers. High temperatures
and pressures will deform and weaken may polymeric hollow membranes
and thin walled hollow tubes. Perfluorinated thermoplastic polymers
useful for housings, sleeves, and hollow conduits may include but
not limited to perfluoroalkoxy (Teflon.RTM. PFA from Dupont,
Neoflon.RTM. PFA from Daikin, Teflon.RTM. PFA Plus from Dupont),
perfluoromethylalkoxy (Hyflon.RTM. MFA from Ausimont), fluorinated
ethylene propylene (Teflon.RTM. FEP from Dupont) and co-polymers of
these. These perfluorinated thermoplastics are chemically resistant
and thermally stable, so that hollow membranes and hollow tubes
made from these polymers, co-polymers, and co-extruded versions of
them can have a decided advantage over less chemically and
thermally stable polymers. Other useful thermoplastic
fluoropolymers that can be used may include homopolymers and
copolymers comprising monomeric units derived from fluorinated
monomers such as vinylidene fluoride (VF2), hexafluoropropene
(HFP), chlorotrifluoroethylene (CTFE), vinyl fluoride (VF),
trifluoroethylene (TrFE), and tetrafluoroethylene (TFE), among
others, optionally in combination with one or more other
non-fluorinated monomer. A modified PTFE, PTFM is suitable as a
shell material or containment material for the lumens as this
material is capable of bonding and adhearing to the potted
material, but is still not melt processable. For less severe
conditions of use, other thermoplastics or their blends may be used
in the practice of this invention and can include but not limited
to, polyether sulfone (PES), ultra high molecular weight
polyethylene (UHMWPE), high density polyethylene (HDPE), and other
polyolefins The invention can also be used for similar but non
identical materials such as polyethylene potting material in a
polypropylene shell or NFA potting material in a PFA shell.
Protrusions, grooves, or channels can be made in housings or
sleeves made from these materials.
[0064] The exchange device may be made from a housing, hollow
conduits, and potting resin that includes several thermally stable,
chemically compatible, and mechanically strong fluoropolymers. The
fluoropolymers may include, for example, a homopolymer or a
copolymer formed from monomer units containing fluorine. The
housing and hollow conduits may be co-extruded and include one or
more layers of fluoropolymer, or different layers of fluoropolymer
on the inner and outer surfaces.
[0065] PFA and FEP are examples of fluoropolymers that can be made
into hollow porous membranes using the Thermally Induced Phase
Separation (TIPS) process. In one example of the TIPS process a
polymer and organic liquid are mixed and heated in an extruder to a
temperature at which the polymer dissolves. A membrane is shaped by
extrusion through an extrusion die, and the extruded membrane is
cooled to form a gel. During cooling the polymer solution
temperature is reduced to below the upper critical solution
temperature. This is the temperature at or below which two phases
form from the homogeneous heated solution, one phase primarily
polymer, the other primarily solvent. If done properly, the solvent
rich phase forms a continuous interconnecting porosity. The solvent
rich phase is then extracted and the membrane dried.
[0066] The housing, endcaps, or sleeves used in exchange devices
may be but are not limited to thick walled conduits that are
cylindrical tubes, conduits having any number of sides including
hexagonal, rectangular or triangular conduits. The housing,
endcaps, or sleeves have an inner dimension capable of containing
one or more hollow thin walled conduits bonded to the interior of
the housing, endcap, or sleeve. The housing or sleeve may be a
thermoplastic, preferably a perfluorinated thermoplastic, but can
also be a thermoplastic coated metal, composite thermoplastic, or
thermoplastic coated ceramic material with grooves that exhibits
chemical compatibility for the bonding process and the intended use
of the device. The housing or sleeves may be formed from
co-extruded thermoplastics with the thermally bonded inner layer
capable of bonding to the potting resin or hollow conduits and the
outer layer providing mechanical support for the housing.
Preferably the inner layer of a co-extruded thermoplastic housing
will have a lower melting temperature than the outer layer.
Alternatively, the housing or sleeves can be molded to have one or
more thermoplastic portions or layers in the bonding region. The
structures such as protrusions, grooves, a combination of these, or
the interior surface of the housing or sleeve may be coated or
molded with a thermoplastic inner layer, for example MFA, to
provide an adhesion layer to the housing or sleeve material. One
skilled in the art would know to look to ASTM tables to find the
permitted housing or sleeve conduit wall thickness for the housing,
endcap, or sleeves for a particular use of the exchange device.
Where a housing, endcap or sleeve includes one or more structures
that are grooves, preferably the depth of the grooves or channels
are in the conduit wall are less than about one half the thickness
of the wall.
[0067] The housing, sleeve, or endcap used to form a single entity
consisting solely of thermoplastic materials, and preferably
perfluorinated thermoplastic materials, can be prepared by first
pretreating the surfaces of both ends of the housing or one or more
sleeve before the potting and bonding step. This can be
accomplished by melt-bonding or sintering a powdered form of the
thermoplastic potting material to the housing, one or more sleeves,
and groove or protrusions on their inner surfaces. The internal
surfaces on both ends of the housing may be heated close to their
melting point or just at the melting point and immediately immersed
into a cup containing powdered
[Polytetrafluoroethylene-co-perfluoromethylvinylether], MFA,
thermoplastic potting resin available from Ausimont USA Inc.
Thorofare, N.J. Since the surface temperature of the heated surface
of the housing is higher than the melting point of the potting
resins, the potting resin is then fused or sintered to the
thermoplastic housing, any channels, grooves, or raised features or
a combination of these for bonding the potting resin, the hollow
conduits, or a combination of these to the housing. A non-limiting
example of raised features or protrusion on the housing or sleeve
surface is the sintered thermoplastic coating 936 illustrated in
FIG. 9. The housing may be polished with a second heat step to fuse
any excess un-melted thermoplastic powder. It is preferred that
each end of the housing or each of the sleeves be treated at least
twice with this pre-treatment. PIG. 9 illustrates an adherent
thermoplastic coating 936 formed on the inside of a thermoplastic
housing with one or more grooves 904 and 912.
[0068] Hollow conduit exchange devices of the present invention,
especially those including one or more porous and or non-porous
hollow tubes or other shaped conduits, are advantageous because
they can be made with high fluid contact surface areas. The high
contact surface area is due to the ability to obtain a very high
packing densities of the hollow conduits in these devices. Packing
density relates to the amount of useful membrane surface per volume
of the device. It is related to the number of tubes, conduits,
fibers, or combinations of these that can be potted in a finished
contactor. The packing density of the hollow conduits such as
hollow fibers, hollow tubes, cords of these and combinations of
these within the shell tube, housing, or sleeve can be in the range
of from 3-99 percent by volume, preferably 20-70 percent by volume,
and more preferably 40-60 percent by volume.
[0069] Hollow fiber microporous membranes can be used for mass
exchange operations such as filtration, gas contacting, and
degassing. Hydrophobic microporous hollow fibers membranes are
commonly used for degasser or contactor applications, with a liquid
to be treated that does not wet the membrane. For gas contacting,
the liquid flows on one side of the membrane and a gas mixture
preferably at a lower pressure than the solution flows on the
other. Pressures on each side of the membrane are maintained so
that the liquid pressure does not overcome the critical pressure of
the membrane, and so that the gas does not bubble into the liquid.
Critical pressure, the pressure at which the liquid will intrude
into the pores, depends directly on the material used to make the
membrane, inversely on the pore size of the membrane, and directly
on the surface tension of the liquid in contact with the gas phase.
Typical applications for contacting membrane exchangers are to
remove dissolved gases from liquids, "degassing"; or to add a
gaseous substance to a liquid. For example, ozone can be added to
very pure water to wash semiconductor wafers.
[0070] Exchange devices of the present invention may be operated
with the process fluid contacting the inside or the outside surface
of the potted hollow tubes or conduits, depending on which is more
advantageous in the particular application. Baffles and other
inserts may be mounted on the inside of the housing or fluid flow
fittings to effect fluid distribution on the shell side of the
hollow conduits and housing.
[0071] Potting is a process of forming a liquid tight seals around
each hollow conduit, for example hollow tube or hollow fiber,
within the housing. The tube sheet or pot separates the interior of
the housing for the exchanger or contactor from the environment.
The potting material is bonded to the housing including surface
structures such as protrusions, channels, or grooves. This bonding
may include physical mixing of melted materials as during welding
or fusion of thermoplastics, mechanical interlocking of material,
as well as chemical bonding of the materials. Preferably the bond
between the housing and its grooves provides a fluid tight seal.
The bond to form the unitary end structure may be formed between
the potting material and the housing surfaces and housing groove
surfaces. The bond may be the result of a union of the potting and
housing materials by fusion, melting, or welding. Preferably the
potting and housing, including any of the housing's coated
surfaces, are thermoplastics that can be fused or welded together
by various heating methods such as but not limited to welding,
induction heating, ultrasonic bonding, infrared heating, and
potting. The housing and potting material may be the same or
different materials, for example the housing may be PFA and the
potting MFA. The potting material can be thermally bonded to the
housing vessel and channels, grooves, or raised structures on the
inside of the housing in the present invention to produce a unitary
end structure. The inside of the housing and channels may be coated
with a layer of the potting resin sintered, molded or co-extruded
to the one or more inner housing surfaces to facilitate the bonding
between the potting and housing.
[0072] Fluidly sealed refers to potting resin, thermoplastic
housing, hollow conduits and combinations of these that have either
welded or fused together or formed a mechanical bond together that
is characterized in that fluid does not flow past the bonded areas.
For hollow conduits like fibers or tubes in the potted area, fluid
flows through inside of the tubes and is physically separated from
fluid on the outside of the hollow tubing or fiber by the conduit
walls and potting.
[0073] The term unified terminal end block or unitary end structure
describes a mass or well of a thermoplastic resin bonded to one or
more hollow conduits such as hollow tubes, hollow fibers, or cords
of these and a housing or sleeve. Bonding of the resin with the
housing and conduits can include mechanical bonds between the resin
and structures of the housing and conduits, chemically bonding,
welding, or fusion bonding, or any combination of these. FIG. 3
illustrates an example of hollow conduits 318 and 320 fusion bonded
to a thermoplastic resin 310 and filling a portion of one or more
channels 304 in the housing inner surface 316 that was used to form
a unified terminal end block structure. FIG. 3 illustrates a
unified terminal end block structure that has been cut open to
expose the hollows of the tubes. The thermoplastic resin 310
occupies a portion of the grooves 304 and spaces between the tubes
330 and forms a bonded structure, that is acombination of
mechanical and welded bonding, between the resin, tubes, grooves
and housing walls. The resin may also bond to a layer of sintered
thermoplastic material on the housing and groove surfaces (not
shown).
[0074] The unitary end structure(s) may be cut or machined and the
lumen of the hollow conduits exposed. The potting resin and hollow
tube ends may be opened so that the resin and tube ends are even
with the housing or sleeve end as illustrated for a single end
portion of an exchange device shown in FIG. 3 or FIG. 7D.
Alternatively, potting material and tubing may be removed and
opened to a region located below one or more of the end of the
housing or sleeve end as illustrated in FIG. 1A, FIG. 1B, and FIG.
7C. For example, as shown in FIG. 1A, potting resin 106 is removed
from the housing end 132 or 121 to a region below the ends of the
housing 128 or 117. Similarly in FIG. 1B, potting can be removed
from the housing end 163 or 153 to a region below or inside the
ends of the housing shown by 161 or 155.
[0075] Porous or skinned hollow fiber diameters can range from
100-1000 um in diameter. Wall thickness should be minimized and
preferred thickness is 25-350 um. Hollow fiber beds can consist of
mats of fibers with thickness ranging from 1-25 cm in depth and
length and width of 10-100 cm. The beds can be circular with
diameters of 1-25 cm and lengths of 20-300 cm and contain multiple
baffles to distribute gas throughout the bed of fibers. Hollow
fibers in the contactor may be straight or can be loosely packed.
The hollow fibers may be extremely long and wrapped to a length
nearly equivalent to the length of the device, effectively closing
off the ends of the fiber to melt resin flow during the potting
process.
[0076] Hollow conduits that are non-porous hollow tubes made from
thermoplastics with outside diameters ranging from 0.007 to 0.5
inches (0.017 to 1.27 cm), and more preferably 0.025 to 0.1 inches
(0.063 to 0.25 cm) may be used in the exchange devices of the
present invention. For heat exchanger or mass exchange through
non-porous hollow tube, preferably the hollow tubes may have a wall
thickness ranging from 0.001 to 0.1 inches (0.0025 to 0.25 cm),
preferably 0.003 to 0.05 inches (0.0075 to 0.0125 cm) in thickness.
For mass exchange through non-porous hollow tubes--gas
separations--the thickness of the hollow tube wall can be made
thinner. The hollow tubes can be used individually, or the tubes
can be combined by braiding, plaiting, or twisting them to form
cords comprised of multiple hollow tubes. The hollow tubes may be
extremely long and wrapped to a length nearly equivalent to the
length of the device, effectively closing off the ends of the
hollow tube to melt resin flow during the potting process.
[0077] Thermoplastic hollow conduits may include co-extruded
thermoplastic tubes and porous hollow fibers that can be potted
into sleeves or housings to form exchange devices. The co-extruded
tubing or porous hollow fibers can, for example, have one or more
outer layers or portions that include a thermoplastic with a lower
melting point or melt flow index that the inner most portion or
layer of the co-extruded tubing. The layers of the co-extruded
tubing are thermally bonded or fused to one another. One
non-limiting example of this type of co-extruded tubing has an MFA
outer layer and a PFA inner layer. Another example is a hollow tube
having an FEP outer layer and a PFA inner portion. One or more of
the layers of the co-extruded hollow conduit may include a
thermally conductive material, preferably one or more of the outer
layers of the hollow conduit includes a thermally conductive
material. For example the MFA outer portion of a co-extruded tube
may include a conductive carbon particles. During potting, the
conductive particles in the MFA of the tubes will mix or combine
with NWA from adjacent hollow tubes or with the thermoplastic
potting resin. Unpotted regions of the co-extruded tube will retain
the MFA layer with the thermally conductive particles as
illustrated in FIG. 2C. This thermally conductive layer will
contact the fluid on the outside of the tube and transfer energy to
the fluid on the lumen of the tubing.
[0078] The one or more thermoplastic materials for the co-extruded
tubing can be selected for their chemical and or physical
properties, for example thermal conductivity, as well as properties
that make the tube suitable for bonding with each other, bonding to
a resin, or a combination of these used in the potting process. For
example, during potting, the outer MFA layer of the tubing will
melt and fuse with the MFA from adjacent hollow tubes, fuse with
resin in the pot, or a combination of these while the inner PFA
layer of the tube keeps the lumen opened. Potting temperature or
fusion temperature can be chosen so that the one or more outer
layers of the co-extruded tubing melt and fuse or combine with
adjacent tubes or a thermoplastic potting resin but the inner layer
remains open. For tubing having an outer MFA layer and an inner PFA
layer, the preferred potting temperature is between about
290-305.degree. C.; potting temperatures for other co-extruded
thermoplastic hollow tubes may be determined by routine
experimentation and use of the testing manifold of FIG. 8.
[0079] As illustrated in FIG. 1A-C, an exchange device may include
one or more co-extruded thermoplastic hollow tubes. Each tube has
an inlet and an outlet for fluid flow, the hollow tubes fluidly
sealed by a bond with other co-extruded thermoplastic hollow tubes
or to a thermoplastic resin. The inlet of the hollow tubes may be
fluidly sealed by a bond to a sleeve to provide a fluid to the
hollow portion of the tubes and the outlet of the hollow tubes
fluidly sealed by a bond to another part of the sleeve or to a
second sleeve to provide for removal of fluid from the hollow
portion of the tubes. As illustrated in detail in FIG. 7C, the
co-extruded tubes may be bonded together and to the housing by
thermoplastic resin 722. The exchange apparatus may have a sleeve
or housing that encloses the hollow tubes, for example 124 in FIG.
1A, or 186 in FIG. 1C. Preferably the hollow tubes, potting resin,
and the housing are thermoplastics, and even more preferably,
perfluorinated thermoplastics.
[0080] Hollow thermoplastic conduits and co-extruded hollow
thermoplastic conduits used in the invention can be impregnated
with thermally conductive powders or fibers to increase their
thermal conductance. Examples of useful thermally conductive
materials include but are not limited to glass fibers, metal
nitride fibers, silicon and metal carbide fibers, or graphite. The
thermal conductivity of the hollow thermoplastic tubes or
impregnated thermoplastic hollow tubes useful in this invention for
energy exchange is preferably greater than about 0.05 watts per
meter per degree Kelvin. The co-extruded hollow tubes may includes
a thermal heat conductor material mixed or combined with any of the
layers of the hollow tube, preferably the outer layer. The
thermoplastic of the outer layer can include, for example, carbon
nanotubes, graphite fibers made from petroleum pitch that can have
thermal conductivity values of about 500-1000 W/mK, carbon fibers
based on polyacrylonitrile (PAN) that can have thermal
conductivities of about 10 W/mK, electrically insulative ceramic
fillers like boron nitride that can have a thermal conductivity of
about 60-80 W/mK, aluminum nitride with a thermal conductivity of
about 300 W/mK, or mixtures of these.
[0081] In the practice of various embodiments of the present
invention, combinations of porous and non-porous hollow tubes may
be potted together. Such devices may be used to limit the amount of
mass transferred while maximizing the amount of energy transferred
between a process and an exchange fluid. For example temperature
conditioned aqueous sulfuric acid may be re-circulated on the shell
side of an exchange device to condition the temperature of air in a
cleanroom and remove trace amounts of organic amines from the air.
Temperature conditioning of the air may be changed by the number of
non-porous potted hollow tubes while the amount of air in contact
with the aqueous sulfuric acid scrubbing solution for mass exchange
is controlled by the number and type of porous potted fibers
present in the device.
[0082] Baffles may be useful in the practice of the present
invention to enhance the mixing and distribution of fluids on
either side of the hollow tube contactor or exchange device (not
shown in FIG. 1). The hollow fiber contactor or exchanger can be
used in a single pass mode or in a re-circulating mode for either
or both the process fluid and or the exchange fluid as illustrated
in FIGS. 4-6. Preferably the contactor is provided with two or more
fluid ports or fittings on the shell and lumen side of the housing.
Usually one port serves as a fluid inlet and the second serves as a
fluid outlet. The ports or fluid connections on the shell side of
the contactor have restricted fluid flow with the lumen side inlet
and outlet port because of the porous wall of the membrane hollow
conduits or the non-porous wall of the hollow tubes. Preferably the
fluid flowing within the tubes or and or fibers and the shell side
fluid flowing on the outside of the tubes and or fibers flow
counter current to each other as illustrated in FIG. 8; preferably
the fluid flows in a manner which maximizes a cross flow of the
fluids with respect to one another.
[0083] FIG. 2B illustrates different types of grooves- those in the
potted region (244, 246, 250) and those which may lie outside the
potted region 242. Grooves in the potted region bond with the
potting resin or thermoplastic. As shown in FIG. 2 B, a groove 242
can be added outside of the potted region. There may be one or more
of these grooves outside the potted region and these grooves or
channels may be on the inside or outside surface of the housing.
Grooves including but not limited to 244, 246, 250 bond with the
potting resin and are considered to be in the potted region and can
form a unitary structure with the potting resin and hollow tubes.
The number of grooves and their surface area may be changed without
limitation. Without wishing to be bound by theory, the groove 242
may be used to reduce radial pressure on the pot and shell
interface by hinging at this point. The shell may be pressurized by
the process fluid which tends to expand the thermosplastic shell.
The stress relief on the inside diameter or the outside diameter
may allow the shell to flex about this feature, thereby reducing
stress on the pot and shell interface and maintaining its
integrity.
[0084] As shown in FIG. 2, the grooves or equivalently channels may
be made by machining or molding the grooves in the housing. Without
limitation the grooves may be concentric and separated by equal or
unequal spacing as shown in FIG. 2B; the grooves may be in the form
of one or more spirals along the inside of the tube, they may
consist of a series of groove channels along the axis of the
housing; a hatched pattern, cross hatched pattern, variations of
these, or a combination of these. The grooves or channels are
preferably located in from the end of the housing so that the
potting material may cover over and bond with one or more of the
channels. The channels and the housing wall may be covered or
coated with a sintered thermoplastic material applied to the
grooves as disclosed herein for bonding with the potting material.
Preferably the depth of the grooves or channels permits the housing
to maintain a pressure and temperature rating suitable for its use.
One skilled in the art would know to look to ASTM tables to find
the permitted wall thickness for the use of the potted device.
Preferably the depth of the grooves or channels are less than about
one half the thickness of the housing or sleeve wall.
[0085] Groove, channel, or slot refer to narrow openings or
depressions in the housing, endcap, or sleeve wall and may be used
interchangeably. In a preferred embodiment the grooves are
interconnected with each other as illustrated for one end portion
of a housing in FIG. 7C or in FIG. 10. The channels or vent slots
allow gas may be generated or trapped in the groove during the
potting process to move out from the channel. The removal of gases
from the channel allows potting melt to fill the grooves, to bond,
and optionally interlock the potting material with the housing. The
vent channels between the grooves can have a volume that allows gas
in a groove to escape and preferably the vent channels have the
same depth as the grooves. The number and distribution of channels
between the grooves should be sufficient to vent gases present in
the housing during potting. The number can be varied depending upon
for example the size of the housing, the wall thickness of the
housing, and the amount of gas that needs to be vented during the
potting process. The depths of the vent channels may be varied
between grooves or sloped to further facilitate the removal of
gases from the grooves. In an exchange apparatus the housing may
have one or more end portions with grooves.
[0086] The groove and vent edges as well as the bottoms of the
grooves may have but are not limited to square, beveled, or a
radius finish; the edge of the top and bottom most groove in the
housing may be slotted or vented with the slots tapering to the
inner wall (not shown). One or more of the grooves in the end
portion of the exchange device are preferably interconnected by
slots or channels and the exchange device may have one or more end
portions.
[0087] The grooves or channels may have a shape that maximizes
surface area of contact and bonding between the potting material
and the housing grooves. The depth and angles of the sidewalls of
the grooves may be made to vary the amount of bonding surface
between the potting material and the grooves. Where an increase in
the amount of shear component for the bond between the channel and
potting is desired, deep thin channels are preferred. The
additional surface area of the channels, some of which may not be
parallel to the housing walls, result in fusion and adhesion of the
potting resin to all faces or surfaces of the groove. The radial
force created by thermal or pressure expansion of the device during
use may have a portion of this force transferred to a shear
component through bonding of the potting resin with the surfaces of
the grooves which greatly improves the strength of the device.
[0088] While grooves and channels are preferred for bonding the
thermoplastic resin to the housing of the present invention, it is
also contemplated that raised structures permanently bonded or
fused onto the inner surface of the housing tube could be made and
used with the same effect as channels or grooves for purposes of
bonding the thermoplastic potting resin to the housing. Such raised
structures may be considered as an equivalent to grooves or
channels for purposes of the present invention. A sintered
thermoplastic bonded to the inner housing wall is a non-limiting
example of raised surface structures or protrusions on the housing.
Preferably the structures result in bonding or fusion between the
raised structures and the potting resin. Preferably the bonding
transfers a portion of the radial force into a shear component of
force between the potting resin and the raised structure.
[0089] Channels or grooves may be formed in a housing which can
include, endcaps, sleeves, or any of these bonded to a housing
wall. The depth and area of the grooves or height of protrusions on
the inner wall of the housing that are used to bond with a
thermoplastic resin and bond to one or move hollow tubes are chosen
to bond with the resin and form a fluid tight seal that maintains
separation between fluids on the inside and outside of the hollow
tubes. The depth and area of the grooves, vent channels, or height
and area of protrusions on the inner wall of the housing for a
particular use of the exchange device may be determined using the
test manifold of FIG. 8 and the application parameters for the
exchange device including but not limited to temperature, pressure,
and chemical reactivity of the fluids contacting the exchange
device. The device preferably includes 1-4 grooves, more preferably
2-3 grooves each having a depth that is within the safety limits
for use of the device, preferably about half the housing wall
thickness or less, and a width opening or height of about 0.05 to
0.5 cm, preferably 0.1 to 0.3 cm. Where they are used, vent
channels can be formed between the grooves along the wall of the
housing or sleeve. Preferably there are about 4-8 vent channels per
groove and the depth of the vent channels the same or less than
those of the grooves.
[0090] It is also contemplated that additional means for reducing
stress between the housing and the potting material may be used in
addition to channels or grooves in the housing. For example a
housing with channels in the inside of the housing may have the
outer wall of the housing thinned by machining to relieve pressure
on the interface between the potting material and the shell. The
thinned material will yield to material movement more readily,
allowing temperature and pressure effects to be self compensating
by flexible components to maintain the integrity of the bond
between the potting resin fused to the housing.
[0091] The exchange device may include one or more hollow conduits
potted at each end into to a thermoplastic housing. Integral
exchange devices made with hollow tubes potted into a thermoplastic
housing, a packing density of about 40-50%, but without one or more
grooves in the housing were made and used as heat exchangers as
summarized by the data in Table 1. It would be reasonable to expect
that exchange devices of the present invention, with for example
co-extruded tubes or grooves in the housing, having similar numbers
of hollow conduits would have exchange performance similar to those
shown in Table 1. TABLE-US-00001 TABLE 1 # hollow heat tubes-
transfer Inlet Outlet tube Inlet Outlet shell Shell approx tube
surface tube tube flow shell shell flow ID 13 length area temp temp
rate temp temp rate (inches) twist/ft (inches) (ft.sup.2) .degree.
C. .degree. C. (lpm) .degree. C. .degree. C. (lpm) 2.25 680 18
14.15 70.66 45.26 5.55 13.09 63.14 2.97 2.25 680 18 14.15 70.02
35.77 3.80 13.05 58.83 2.97 2.25 680 18 14.15 68.15 26.71 2.64
13.24 52.17 2.97 2.75 1000 8 9.25 70.5 48.87 9.5 12.46 49.58 5.8
2.75 1000 8 9.25 70.5 42.8 7.2 12.4 46.8 5.8 2.25 680 27 21.22 70.1
22.91 4.4 14.5 46.5 6.6
[0092] Heat transfer between water on the lumen side of the hollow
tubes and water on the shell side of the hollow tubes fluids at the
inlet temperatures given in Table 1 were approximately the same
(within experimental error of less than about 10%) through the
hollow tube walls potted in the device. Calculated heat, Q,
transferred by the shell fluid ranged from about 8,000 watts to
10,000 watts at different tube flow rates for the exchange device
in Table 1 with 2.25 inch diameter and 18 inch length; Q ranged
from about 13,900 watts to 15,000 watts at different tube flow
rates for the 2.75 inch diameter housing with 8 inch length, and Q
for the 2.25 inch inside diameter device with 27 inch length was
about 14,700 watts.
[0093] One advantage of the present invention is the large surface
area of hollow conduit that can be potted in a device in a small
volume device. For example, the devices of Table 1 with packing
densities of from about 40 to 50%, have approximately 11 cm.sup.2
of transfer surface area per cubic centimeter of housing volume.
Higher packing densities would give a higher value, and lower
packing densities would give smaller value.
[0094] One embodiment of the present invention is an exchange
device including one or more potted hollow conduits capable of
transferring heat from a first fluid to a second fluid through the
walls of the hollow conduits, the exchange device integral at a
temperature of at least 100.degree. C. and a pressure of at least
50 psig, the temperature below the continuous use temperature or
melting temperature of the hollow conduit material; preferably the
exchange device remains integral at a temperature of at least
160.degree. C. and a pressure of at least 70 psig, the temperature
below the continuous use temperature or melting temperature of the
hollow conduit material. Preferably the exchanger has a packing
density by volume of hollow conduits between 20 and 70%; more
preferably 40-60% by volume. A device configured with potted hollow
conduits to have about 9 ft.sup.2 (0.85 m.sup.2) of exchange
surface area is capable of exchanging at least about 13,000 watts
of energy between a fluid flowing on a first side of the hollow
conduit with a second fluid flowing on a second side of the hollow
conduits; preferably the first fluid flows at 9.5 lpm or less on a
first side of the hollow conduits and the second fluid flows at 5.8
lpm or less on the second side of the hollow conduits. The
exchanger is capable of maintaining its fluid integrity under a
variety of test conditions of temperature, pressure, and duration
as shown by the results listed in Tables 2-5 with packing densities
in the range of 20 to 70 percent. Where the hollow conduits of the
devices are similar to those used for the exchangers of Table 1, it
would be reasonable to expect that exchange devices of the present
invention could be made and have similar exchange capabilities.
[0095] For devices prepared using porous hollow fibers, devices
having a similar packing density as shown in Table 1 may be made
and similar transfer surface areas obtained (not including the
internal membrane area).
[0096] Various aspects of the present invention will be illustrated
with reference to the following non-limiting examples.
EXAMPLE 1
[0097] This example compares the ability of various potted exchange
devices to withstand stress testing.
[0098] Table 2 shows the advantage of adding the grooved interface.
The original PFA design showed loss of housing to potting material
integrity at 120.degree. C. The temperature/Pressure test is a
method of accelerating long term ambient conditions for the device.
The MFA only device showed loss of bond integrity at 150.degree. C.
All tests on MFA devices with the improved interface are integral
up to 200.degree. C. and beyond, the PFA device with the improved
groove or channel interface is also integral at temperatures up to
160.degree. C. This device was destructively tested after the
160.degree. C. to determine the strength of the bond. The strength
of the bond is determined by cutting off thinning the outside of
the device leaving approximately 0.080-0.100'' wall thickness.
Axial and circumferential cuts are made into the shell
approximately 0.25'' above the potted area, leaving a tab
approximately 0.5'' wide by 0.25 long. The tab can then be used to
pull up on the material in an attempt to pull apart the shell
material from the potted material. In this manner the strength of
the bond can be tested qualitatively by force, or quantitatively by
an instrument such as an Instron.
[0099] The process of this example improves the overall strength of
the device by eliminating stress at this interface, and
transferring the stress to the potted material entrapped in the
grooves. Without wishing to be bound by theory, the grooves, and
their additional surface area, some of which is not parallel to the
housing walls, also add adhesion of the potting resin to at least a
portion, and preferably all surfaces or faces of the groove, adding
a shear component to a radial force created by thermal or pressure
expansion of the housing shell. This shear component greatly
improves the strength of the device. TABLE-US-00002 TABLE 2 Test
Condition 120.degree. C., 130.degree. C., 140.degree. C.,
150.degree. C., *160.degree. C., *170.degree. C., *180.degree. C.,
70 psig, 5 h 70 psig, 5 h 70 psig, 5 h 70 psig, 5 h 5 hrs 5 hrs 5
hrs PFA tube, integrity original loss PFA tube integrity w/stress
groove loss relief PFA tube Passed Passed Passed Passed Passed
w/grooved ID MFA, original Passed Passed Passed integrity loss MFA
tube Passed Passed Passed Passed Passed Passed passed w/stress
groove relief MFA tube Passed Passed Passed Passed Passed Passed
passed w/grooved ID Tubes flamed Passed Passed passed passed passed
passed with rotational fixture, MFA original Tubes flamed Passed
Passed passed passed passed passed with rotational fixture, MFA
threaded ID
EXAMPLE 2
[0100] This prophetic example illustrates that the potted devices
of the present invention may be used for heat and or mass exchange
including but not limited to filtration, gas contacting, heat
exchange, gas scrubbing and combinations of these.
[0101] The potted devices may be placed in an apparatus for
cleaning or chemical modification of substrate surfaces including
but not limited to single wafer cleaning tools, re-circulating
cleaning baths. The device can also be used for temperature
conditioning of fluids prior to disposal (such as hot sulfuric acid
used to remove polymer coatings from optical fibers and
photoresists from coated silicon wafers). As illustrated in FIG. 4
an exchange fluid or working fluid 450 in a tank 448, (or a chiller
or cold water from a building supply source not shown) can be
directed to flow through one side of the potted heat exchanger 416.
A pump 446 may be included to re-circulate the exchange fluid 450
if necessary and particle filters 408 and valves 412 may also be
used. Process fluid 428 from a cleaning or process bath, including
but not limited to solvents, acids, bases, oxidizers, and useful
combinations and mixtures of these may be re-circulated on the
shell side of the hollow tubes in the exchange device and the
process fluid temperature conditioned (heating or cooling) by
contact with the exchange fluid 450 through the hollow tube walls.
The temperature conditioned fluid 428 is returned to the process
bath or tool for use on the substrates 434. As shown in FIG. 5, a
potted exchange device 528 of the present invention may be used to
cool a process or cleaning fluid prior to discharge at outlet valve
532. An example of such fluids includes but are not limited hot
sulfuric or phosphoric acids.
EXAMPLE 3
[0102] This example illustrates a potted membrane device and method
of making it suitable for use at high temperature.
[0103] A potted filtration device having a 2.25'' ID and 12.65'' in
length MFA housing, and contained about 3000 MFA porous hollow
fibers. The device contained 4 grooves each having a depth of 0.25
cm and height 0.15 cm. Vent channels were formed between the
grooves. There were about 6 vent channels per groove and the depth
of the vent channels was about 0.15 cm. The potting melt was NFA
heated to 278.degree. C. for 3 days.
[0104] The device was tested for fluid integrity under the
following conditions. Hot fluid at the temperature of 100.degree.
C. to 210.degree. C. under pressure was fed into the shell side of
the device at a very slow flow rate and no fluid flow on the tube
side. Both end-caps were capped. Visaully inspect the device daily.
Any accumulation of oil on the lumen side indicate device failure.
The result from this experiment is listed in Table 3.
[0105] A test setup which can be used to test these devices is
shown in FIG. 8. During testing the fluid entered at the inlet 820
and flow out at the outlet 838 on the shell side. The fluid used is
the heat transfer fluid HT3 made by the Lube-tech lubrication
Technologies, Inc. It was heated 826 with Chromalox heat exchanger
model #NWH0-34515 and pressure was control by the outlet flow valve
838. The valve 838 was closed to restrict the flow and increase the
fluid pressure which was measured using an Omega pressure gauge
822. The fluid flow at about 0.46 gallon per minute at 70 psi. The
test was stopped at 210.degree. C., because of fluid degradation.
The results of the tests are summarize in Table 3. TABLE-US-00003
TABLE 3 Integrity Test Results for devices made with venting slots
in grooves. Temperature Pressure Duration Device Test (.degree. C.)
(psig) (hours) Integrity 1 100 160 100 Passed 2 160 70 24 Passed 3
170 70 24 Passed 4 180 70 24 Passed 5 190 70 24 Passed 6 200 70 24
Passed 7 210 70 8 Passed
EXAMPLE 4
[0106] This example illustrates co-extruded hollow tubing potted
into a thermoplastic resin to form hollow tubes bonded into a
thermoplastic sleeve.
[0107] In the preparation of potted devices, the process window can
vary and is dependent on the MFA tubing material properties
(melting point, melt flow index, tubing dimension and geometry).
These properties can vary from batch to batch and can be
accommodated by varying and adjusting process variables like
temperature and potting time. Overheating during potting can result
in the collapsed of the tubing and under heating can cause some
tubing not to bond during the potting. Various techniques may be
used to prevent tubing collapse, for example putting a metal wire
into the fiber or tube lumen or filling the lumen with an inorganic
salt. These methods however are labor intensive, costly and may add
contaminants to the device.
[0108] Co-extruded tubing can be potted to sleeves or housings to
form exchange devices. One embodiment of the invention is
perfluorinated co-extruded tubing or articles such as exchange
devices made from it. The co-extruded perfluorinated tubing can
have one or more outer layers or portions that include a
perfluorinated thermoplastic with a lower melting point or melt
flow index than the inner most portion or layer of the co-extruded
tubing. The different perfluorinated layers of the co-extruded
tubing are thermally bonded to one another. One non-limiting
example of such co-extruded tubing has an MFA outer layer and PFA
on the inside layer as illustrtated in FIG. 12A and shown in FIG.
12C. Both perfluorinated thermoplastic layers are thermally bonded
to each other during extrusion of the tubing. The overall dimension
of the tubing shown is ID 0.004''.+-.0.002'' (0.01.+-.0.005 cm)
with an MFA outer wall 0.003''.+-.0.001'' (0.0076.+-.0.0025 cm) and
PFA wall 0.003''.+-.0.001'' (0.0076.+-.0.0025 cm). This tubing may
be obtained from Zeus Industrial Products, Inc., Orangeburg, S.C.,
USA.
[0109] An exchanger sample was made using five 3 inch (7.6 cm) long
MFA outer layer/PFA inner layer co-extruded tubes thermoplastic
hollow conduits inserted into a 3/8 inch (0.95 cm).times.3 inch
(7.6 cm) PFA shell. This assemble was placed in a pool of molten
MFA at 300.degree. C. for 16 hours. The sample was removed, cool
down and cut opened to exposed the lumen. The sample was analyzed
under the light microscope as shown in FIG. 13B and FIG. 13D. The
MFA potting portion melted and fused in the pot, however as shown
the tubes did not collapse under these potting conditions. A sample
made using all MEA hollow tubes of similar length, wall thickness,
and diameter completely collapsed the tube hollows when potted in a
pool of molten MFA at 300.degree. C. This sample was analyzed under
a light microscope as shown in FIG. 13A and FIG. 13C. This example
illustrates the greater processing latitude available to make
potted exchange devices when using co-extruded hollow tubes with
higher melting point inner layer. Variations in hollow tube
thermoplastic properties or heating equipment which may cause
complete collapse of tubes during potting can be avoided by using
co-extruded hollow tubes.
EXAMPLE 5
[0110] This example illustrates the fabrication and integrity of an
exchange device made with one or more co-extruded hollow conduits
potted in a housing.
[0111] A bundle of 650 twisted and looped co-extruded tubing, about
13 twists per foot was made. The tubing were 8.7'' long, with
0.0042'' internal diameter and a wall thickness of 0.006''. The
tubing were made from two materials, MFA and PFA (Dupont 450 HP)
thermally bondede to each other. The outer wall was MFA and the
inner wall was PFA. Both the MEA and PFA layers had a thickness of
about 0.003 inches, total wall thickness of about 0.006 inches. The
bundle was placed in a shell made from MEFA, having a 2.25'' ID,
2.88'' OD and 8.7'' long. The shell contained 3 internal grooves on
both ends. Each groove was 0.25 cm in depth and 0.15 cm in width.
The inside shell or housing wall on each end was sintered with a
layer of powdered MFA.
[0112] The packing density was approximately 40%. The shell was
placed in a heater block with a 4'' ID by 4'' deep cavity. The
cavity was lined with a layer of aluminum foil. The shell was held
vertically in the cavity with clamp. 310 grams of Ausimont's MFA
940AX resin was poured into the space between the shell and the
cavity wall. The heater block was then heated to 297.degree. C. and
held at the temperature for 2 days. After 2 days the heater block
was cooled slowly to 150.degree. C. and then to room temperature.
The shell with tubing was removed. The opposing end of the tubing
was sealed to the opposite end of the housing using a similar
potting method described. A cut was made across the diameter of the
shell through the pots, at a position above the looped ends in the
bundle to expose the hollow of the hollow conduits. Excess potting
material was removed. Two 3/4'' PFA fluid fittings were thermally
bonded to the shell.
[0113] The device was tested for fluid integrity under the
following conditions, hot fluid at a temperature of 140.degree. C.
to 200.degree. C. under pressure. The heated fluid was fed to the
shell side of the device at 6 liters per minute with no flow on the
tube side. Both end of the device were uncapped and expose to air.
Visual inspected the device daily. Any accumulation of oil on the
tube side indicated device failure. The result from the test is
listed in the Table 4. The test set up is generally shown in FIG. 8
and described in Example 3.
[0114] The results of the tests show that a perfluorinated exchange
device with one or more hollow conduits bonded to the housing, the
housing prepared with one or more grooves, remains integral under
these test conditions. TABLE-US-00004 TABLE 4 Integrity Test Result
for device made from co-extruded tubing with grooved shell Fluid
Fluid pressure Duration Device Time Temperature(C.) (psig) (hours)
Integrity Day 1 140 50 24 Passed Day 2 160 50 24 Passed Day 3 180
50 24 Passed Day 4 200 50 24 Passed Day 5-10 140 50 100 Passed
EXAMPLE 6
[0115] This example illustrates potting a mixture of co-extruded
thermoplastic hollow tubing (MFA outer wall and PFA inner wall) and
hollow tubing made from MFA to make an exchange device.
[0116] Co-extruded tubing device example. A bundle of 650 twisted
(13 twists per foot) and looped co-extruded tubing was made.
Approximately 2/3 of the 650 tube bundle were hollow tubes made
from MWA only, approximately 1/3 of the 650 tubes were made from
co-extruded MFA/PFA hollow tubes. The tubing was about 8.7'' long,
with 0.0042'' internal diameter and a wall thickness of about
0.006''. The two tubing materials were: hollow tubes of MFA only,
and co-extruded hollow tubes with an MFA outer layer and a PFA
(Dupont 450 BP) inner layer. For the co-extruded tubes, both the WA
and PFA layers had a thickness of about 0.003 inches, total wall
thickness of about 0.006 inches. The bundle was placed in a shell
made from MFA, having a 2.25'' ID, 2.88'' OD and 8.7'' long. The
shell contained 3 internal grooves on both ends. Each groove was
0.25 cm in depth and 0.15 cm in width. The inside shell wall on
each end was sintered with a layer of powdered MFA.
[0117] The packing density was approximately 40%. The shell was
placed in a heater block with a 4'' ID by 4'' deep cavity. The
cavity was lined with a layer of aluminum foil. The shell was held
vertically in the cavity with clamp. About 310 grams of Ausimont's
MFA 940AX resin was poured into the space between the shell and the
cavity wall. The heater block was then heated to 295.degree. C. and
held at that temperature for 48 hours. After 2 days the heater
block was cooled slowly to 150.degree. C. and then to room
temperature. The shell with tubing was removed. The opposing end of
the tubing was sealed to the opposite end of the housing using a
similar potting procedure. A cut was made across the diameter of
the shell through the pots, at a position above the looped ends in
the bundle. Excess potting material was removed. Two 3/4'' PFA
fluid fittings were thermally bonded to the shell.
[0118] The device was tested for fluid integrity under the
following conditions, hot oil fluid heated at a temperature of fro
100 to 140.degree. C. under pressure was fed into the shell side of
the device at 6 liters per minute with no fluid flow on the tube
side. Both end of the device were uncapped and expose to air. The
device was visually inspected daily. Any accumulation of oil on the
tube side indicated device failure. The conditions and result from
the test is listed in the Table 5. The test set up is shown in FIG.
8 and described in Example 3. TABLE-US-00005 TABLE 5 Integrity Test
Result for device made from co-extruded tubing with grooved shell
Fluid Fluid pressure Duration Device Time Temperature(C.) (psig)
(hours) Integrity Day 1 100 50 24 Passed Day 2 120 50 24 Passed Day
3 140 50 24 Passed for fibers, housing fluid fitting failed
[0119] The results of the tests show that an exchange device of the
present invention having a mixture of hollow thermoplastic conduits
and hollow co-extruded thermoplastic conduits and one or more
grooves in the housing can remain integral up to a temperature of
140.degree. C. and pressures of 50 psig for at least 24 hours.
[0120] Although the present invention has been described in
considerable detail with reference to certain preferred embodiments
thereof, other versions are possible. Therefore the spirit and
scope of the appended claims should not be limited to the
description and the preferred versions contain within this
specification.
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