(12) United States Patent
`Spadaccini et al.
`
`I lllll llllllll Ill lllll lllll lllll lllll lllll 111111111111111111111111111111111
`US006709492Bl
`
`(10) Patent No.:
`(45) Date of Patent:
`
`US 6, 709,492 Bl
`Mar.23,2004
`
`(54) PLANAR MEMBRANE DEOXYGENATOR
`
`(75)
`
`Inventors: Louis J. Spadaccini, Manchester, CT
`(US); Steven Lozyniak, South Windsor,
`CT (US); He Huang, Glastonbury, CT
`(US)
`
`(73) Assignee: United Technologies Corporation,
`Hartford, CT (US)
`
`6,126,725 A * 10/2000 Tateyama ........................ 96/6
`7/2001 Berndt et al.
`6,258,154 Bl
`6,309,444 Bl * 10/2001 Sims et al.
`.................... 95/46
`11/2001 Spadaccini et al.
`6,315,815 Bl
`6,332,913 Bl * 12/2001 Breitschwerdt et al. ........ 95/55
`6,558,450 B2 * 5/2003 Sengupta et al.
`... ... .. ... ... 95/46
`2001/0037731 Al * 11/2001 Sims et al.
`...................... 96/6
`2003/0010213 Al * 1/2003 Gerner et al. ................. 96/193
`2003/0066426 Al * 4/2003 Ujita et al.
`... ... ... ... .. ... ... .. 96/6
`
`( *) Notice:
`
`Subject to any disclaimer, the term of this
`patent is extended or adjusted under 35
`U.S.C. 154(b) by 0 days.
`
`GB
`
`FOREIGN PATENT DOCUMENTS
`2229650 A * 10/1990
`
`OTHER PUBLICATIONS
`
`(21) Appl. No.: 10/407,004
`
`(22) Filed:
`
`Apr. 4, 2003
`
`Int. Cl.7 ................................................ BOlD 19/00
`(51)
`(52) U.S. Cl. .......................... 96/6; 95/46; 96/13; 96/14
`(58) Field of Search ............................. 95/46, 54; 96/4,
`96/6, 7, 9, 12-14
`
`(56)
`
`References Cited
`
`U.S. PATENT DOCUMENTS
`
`8/1973 Allington
`3,751,879 A
`4,613,436 A * 9/1986 Wight et al. ................ 210/232
`4,788,556 A * 11/1988 Hoisington et al. ........... 347/92
`4,853,013 A * 8/1989 Rio et al.
`.. ... ... .. ... ... ... ... .. 96/6
`4,999,107 A * 3/1991 Guerif ........................ 210/224
`5,238,547 A * 8/1993 Tsubouchi et al. ............... 96/3
`5,693,122 A * 12/1997 Berndt ............................ 96/6
`5,830,261 A * 11/1998 Hamasaki et al.
`............... 96/6
`5,876,604 A
`3/1999 Nemser et al.
`5,888,275 A
`3/1999 Hamasake et al.
`5,980,742 A * 11/1999 Saitoh ..................... 210/198.2
`6,126,723 A * 10/2000 Drost et al. ...................... 96/4
`
`Louis J. Spacaccini and He Huang: Proceedings of TURBO
`EXPO 2002 ASMI: Turbo Expo: Land. Sea & Air 2002 Jun.
`3-6, 2002, Amsterdam, The Netherlands GT-2002-30071.
`* cited by examiner
`
`Primary Examiner-Robert H. Spitzer
`(74) Attorney, Agent, or Firm-Carlson, Gaskey & Olds
`
`(57)
`
`ABSTRACT
`
`A fuel deoxygenator includes a plurality of fuel plates
`defining fuel passages through a housing. A permeable
`membrane supported by a porous substrate is in contact with
`fuel flowing through the fuel passages. A vacuum in com(cid:173)
`munication with the porous substrate creates a differential
`pressure between oxygen within the fuel and the porous
`membrane. The oxygen partial pressure differential causes
`oxygen dissolved within the fuel to migrate from the fuel
`through the permeable membrane away from the fuel. Fuel
`exiting the outlet includes a substantially reduced amount of
`dissolved oxygen.
`
`23 Claims, 6 Drawing Sheets
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`U.S. Patent
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`Mar.23,2004
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`GE-1011.004
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`U.S. Patent
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`Mar.23,2004
`
`Sheet 4 of 6
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`U.S. Patent
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`Mar.23,2004
`
`Sheet 5 of 6
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`US 6, 709,492 Bl
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`U.S. Patent
`
`Mar. 23, 2004
`
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`

`
`This invention relates generally to a method and device
`for removing dissolved oxygen from fuels and specifically to
`a planar membrane for removing dissolved oxygen from
`liquid hydrocarbon fuels.
`It is common practice to use fuel as a cooling medium for
`various systems onboard an aircraft. The usable cooling
`capacity of a particular fuel is limited by coke deposition,
`which is dependent on the amount of dissolved oxygen
`present within the fuel due to prior exposure to air. Reduc(cid:173)
`tion of the amount of dissolved oxygen within the fuel can
`result in the reduction of coke formed within the fuel
`delivery and injection system of the aircraft engine. Increas(cid:173)
`ing the temperature of fuel also increases the rate of the
`oxidative reaction that occurs. It has been determined that
`decreasing the amount of dissolved oxygen present within
`the jet fuel reduces the formation of insoluble products
`referred to as "coke" or "coking". FIG. 1 illustrates the
`amount of coke formation for various grades of aircraft
`fuels. As appreciated from a study of the graph, deoxygen(cid:173)
`ation suppresses coke formation across various aircraft fuel
`grades. Reducing the amount of oxygen dissolved within the
`jet fuel decreases the rate of coke deposition and increases
`the maximum allowable temperature. In other words, the
`less dissolved oxygen within the fuel, the higher the tem(cid:173)
`perature before coke buildup becomes a problem. For many
`fuels, in order to suppress coke deposition, it is generally 30
`agreed that the concentration of dissolved oxygen should be
`reduced below approximately 2 ppm or approximately three
`percent of saturation. Aircraft fuels that currently have
`improved coking performance are generally more expensive
`or require additives, and therefore are not always available. 35
`U.S. Pat. No. 6,315,815, assigned to Assignee of the
`current application, discloses a device for removing dis(cid:173)
`solved oxygen using a tubular gas-permeable membrane
`disposed within the fuel system. Fuel flows through tubes 40
`having an inner surface comprising a permeable membrane.
`As fuel passes along the permeable membrane, oxygen
`molecules in the fuel dissolve into the membrane and then
`diffuse across it and are removed A vacuum or oxygen
`partial pressure differential across the permeable membrane
`drives oxygen from the fuel, which is unaffected and passes
`over the membrane.
`As is appreciated tubular membranes are difficult to
`manufacture and are limited in size and construction by
`tubing sizes and economic factors. Tubular membrane
`bundles arc difficult to scale because performance is highly
`dependent on spacing and geometry and thus hard to predict.
`High pressures are also a concern with tubular membranes.
`Further, space and weight are driving factors for any system
`installed on an airframe, and any reduction in space and 55
`weight provide immediate benefits to the operation of the
`aircraft.
`Accordingly it is desirable to design a permeable mem(cid:173)
`brane system that can remove dissolved oxygen from fuel
`down to the level required to suppress coke formation, and 60
`to configure it such that it efficiently utilizes space, reduces
`weight, is easily scalable, performs predictably, and can be
`manufactured economically.
`
`2
`inlet and outlet. The fuel plate is sandwiched between
`permeable membranes backed by a porous plate. An oxygen
`concentration gradient partial pressure differential created
`between fuel within the fuel flow passages and the porous
`5 plate provides the driving force or chemical potential to
`draw dissolved oxygen from fuel through the permeable
`membrane to reduce the dissolved oxygen content of the
`fuel. The oxygen concentration gradient is manifested by the
`partial pressure differential of the oxygen and drives the
`10 oxygen through the membrane.
`The fuel deoxygenator assembly includes a plurality of
`fuel plates sandwiched between permeable membranes and
`porous backing plates disposed within a housing. Each fuel
`plate defines a portion of the fuel passage and the porous
`15 plate backed permeable membranes define the remaining
`portions of the fuel passages. The permeable membrane
`includes Teflon or other type of amorphous glassy polymer
`coating in contact with fuel within the fuel passages for
`preventing the bulk of liquid fuel from migrating through the
`20 permeable membrane and the porous plate. Trace amounts
`of fuel, nitrogen, and other gases may also migrate through
`the membrane without any deleterious effects.
`The use of a plurality of similarly configured fiat plates
`increases manufacturing efficiency and reduces overall cost.
`25 Further, the size and weight of the deoxygenator assembly is
`substantially reduced over prior art systems while increasing
`the capacity for removing dissolved oxygen from fuel.
`Moreover, the planar design is easily scalable compared to
`previous tubular designs.
`Accordingly, the fuel deoxygenator assembly of this
`invention increases and improves the amount of dissolved
`oxygen that may be removed from fuel while also reducing
`the amount of space and weight required for accomplishing
`fuel deoxygenation.
`
`BRIEF DESCRIPTION OF THE DRAWINGS
`The various features and advantages of this invention will
`become apparent to those skilled in the art from the follow(cid:173)
`ing detailed description of the currently preferred embodi(cid:173)
`ment. The drawings that accompany the detailed description
`can be briefly described as follows:
`FIG. 1 is a graph illustrating examples of Deoxygenation
`suppressing coke formation.
`FIG. 2 is a schematic view of a fuel deoxygenation
`45 system;
`FIG. 3 is a schematic view of another fuel deoxygenation
`system;
`FIG. 4 is a cross sectional view of the fuel deoxygenator
`assembly;
`FIG. 5 is a cross sectional view of plates through the fuel
`inlet;
`FIG. 6 is a cross sectional view of plates through the
`vacuum opening;
`FIG. 7, is a cross-sectional view of fuel passages;
`FIG. 8 is an exploded view of plates comprising fuel flow
`passages within the fuel deoxygenator assembly;
`FIG. 9 is a perspective view of a fuel plate;
`FIG. 10 is a schematic view of fuel passages defined by
`the fuel plate; and
`FIG. 11 is another embodiment of fuel passages defined
`by the fuel plate.
`
`50
`
`US 6,709,492 Bl
`
`1
`PLANAR MEMBRANE DEOXYGENATOR
`
`BACKGROUND OF THE INVENTION
`
`SUMMARY OF THE INVENTION
`This invention is a fuel deoxygenator assembly including
`a fuel plate that defines fuel flow passages between a fuel
`
`65
`
`DETAILED DESCRIPTION OF THE
`PREFERRED EMBODIMENT
`Referring to FIG. 2, a fuel deoxygenator system 10
`includes deoxygenator assembly 12 for removing dissolved
`
`GE-1011.008
`
`

`
`US 6,709,492 Bl
`
`3
`oxygen from fuel flowing, indicated by arrow 13, to an
`engine 14. Fuel pump 24 pumps fuel from fuel tank 22
`through the deoxygenator 12 to the engine 14. A vacuum
`source 21 creates an oxygen partial pressure differential that
`causes migration of dissolved oxygen out of fuel passing 5
`through the deoxygenator 12.
`Referring to FIG. 3, a second embodiment of a fuel
`deoxygenator system 10' is schematically illustrated. The
`oxygen partial pressure differential is controlled by the flow
`of an oxygen-free strip gas such as nitrogen, indicated by
`arrow 11, circulating through a separate circuit 13. Circu(cid:173)
`lating pump 18 circulates the strip gas 11 through an
`accumulator 20 and the deoxygenator 12. Dissolved oxygen
`within the fuel migrates through the deoxygenator 12 and
`into the strip gas 11. A sorbent 16 then removes dissolved 15
`oxygen within the strip gas 11 that recirculates through the
`deoxygenator 12. The type of strip gas 11 used may be of
`any type known to a worker skilled in the art that does not
`contain oxygen. Further, the type of sorbent 16 for removing
`oxygen from the strip gas 11 may be of any type known to 20
`a worker skilled in the art.
`The deoxygenator 12 is designed to operate in either
`system using a vacuum source 21 or a recirculating strip gas
`11 for creating the partial pressure differential that pulls
`dissolved oxygen from fuel.
`Referring to FIGS. 4-6, the fuel deoxygenator assembly
`12 includes a housing 36 with fuel inlet 26 and outlet 28
`along with a vacuum opening 30. The vacuum inlet 30 is in
`communication with the vacuum source 21(FIG. 2). Fuel 30
`flows from the fuel pump 24 to the inlet 26, through the
`outlet 28 to the engine 14. The assembly 12 includes a
`plurality of plates stacked within the housing 36 that define
`fuel flow passages 50 and the vacuum opening 30.
`The fuel flow passages 50 are formed by a plurality of fuel
`plates 46 sandwiched between oxygen permeable composite
`membranes 42 supported by porous substrates 38. The fuel
`plates 46, along with the permeable composite membranes
`42 define fuel flow passages 50 between the inlet 26 and
`outlet 28. The vacuum inlet 30 is in communication with an
`end of each porous substrate 38. Vacuum creates a partial
`pressure gradient in the direction of arrow 34. The partial
`pressure gradient established within each of the porous
`substrates 38 pulls dissolved oxygen from the fuel passages
`50 through the permeable composite membrane 42 and
`porous substrate 38 and out the vacuum inlet 30. A seal 45
`is provided to prevent leakage of fuel between fuel plates,
`and to provide a vacuum seal such that vacuum is pulled
`through the porous substrate 38.
`Referring to FIG. 5, the fuel inlet 26 is shown in cross
`section and fuel entering the assembly 12 flows from the
`inlet 26 in the direction indicated by allow 32 and is
`dispersed into each of the plurality of fuel passages 50. The
`seals 45 at an end opposite of the inlet 26 prevent fuel from
`exiting between the fuel plates 46 and the inner surface of
`the housing 36. Each fuel plate 46 is sandwiched between
`permeable composite membrane 42. An amorphous fluo(cid:173)
`ropolymer coating layer 48 is disposed on a porous backing
`43 that provides the required support structure while still
`allowing maximum oxygen diffusion from the fuel through
`the porous membrane 48. In the preferred embodiment, the
`porous membrane 48 is coated on the porous backing 43 and
`a mechanical bond between the two is formed. In alternative
`embodiments, other bonding methods could be used (e.g.,
`chemical bond, etc.) or other methods of disposition could
`be used (e.g., physical attachment, pressure, etc.) to dispose
`the porous membrane 49 on the porous backing 43. The
`
`4
`porous membrane 48 consists of a 0.5-20 µm thick coating
`of Teflon AP 2400 on a PVDF (polyvinylidene fluoride or
`Kynar®) support approximately 0.005-in. thick with
`approximately 0.25 µm pore size. Odor supports of different
`material thickness and pore size can be used as long as they
`provide the requisite strength and openness. Preferably, each
`permeable membrane 48 is formed from DuPont Teflon AF
`amorphous fluoropolymer, however other materials known
`to a worker skilled in the art are also within the contempla-
`10 tion of this invention, such as Solvay Hyflon AD perfluori(cid:173)
`nated glassy polymer, and Asahi Glass CYTOP polyperfluo(cid:173)
`robutenyl vinyl ether. Each of the permeable composite
`membranes 42 is supported by the porous substrate 38.
`Referring to FIG. 6, each of the porous plates 38 are in
`communication with the vacuum inlet 30. Vacuum is pulled
`in the direction indicated by arrows 34 through the inlet 30.
`The vacuum creates the partial pressure difference that
`draws dissolved oxygen from the fuel flowing through the
`fuel passages 50.
`Referring to FIG. 7, the assembly 12 comprises a plurality
`of fuel plates 46, sandwiched between permeable composite
`membranes 42 and porous substrates 38. The fuel plates 46
`include sides 53 that define sides of the fuel passage 50. The
`fuel passages 50 also include mixing members 52 that cause
`25 fuel flowing though the passages 50 to tumble and mix such
`that all of the fuel contacts the permeable composite mem(cid:173)
`brane 42 to allow for diffusion of dissolved oxygen from the
`fuel.
`Referring to FIGS. 8 and 9, the fuel plates 46 are
`rectangular shaped. The rectangular shape provides easier
`configuration between specific applications because extra
`capacity can be varied by simply adjusting the number of
`fuel plates 46. Further, materials are commonly provided in
`35 rectangular form, thus economic benefits are realized during
`manufacture through the use of a rectangular plate. The fuel
`plates 46 may also be circular. Circular plates provide
`superior strength. One of ordinary skill in the art will
`recognize that alternative shapes, sizes, or configurations are
`40 suitable and within the scope of the invention.
`Referring to FIG. 8, the assembly 12 is composed of a
`plurality of fuel plates 46 sandwiched between permeable
`composite membranes 42 supported by a porous substrate
`38. The porous substrate 38 is a plate supported within a
`45 vacuum frame 40. The vacuum frame 40 defines inlet 58 to
`communicate vacuum from the opening 30 to the porous
`substrate 38. The porous substrate 38 is of a selected
`porosity enabling vacuum from the opening 30 to create an
`oxygen partial pressure differential between the surface of
`50 the porous substrate 38 and the inlet 58. The pore size, open
`volume, and thickness of the porous substrate 38 are set by
`the oxygen mass flux requirement. It is this oxygen partial
`pressure that draws dissolved oxygen through the porous
`membrane 42 from fuel flowing through the fuel passages
`55 50. The porous substrate is made of a material compatible
`with hydrocarbon fuel. Preferably, a lightweight plastic
`material such as PVDF or polyethylene is used. The poly(cid:173)
`ethylene plate is approximately 0.080-in. thick and includes
`a nominal pore size of 20 µm. Although, this is the preferable
`60 configuration, a worker having the benefit of this disclosure
`would understand that plate thickness and pore size can vary
`according to application specific parameters.
`The porous composite membrane 42 is supported by the
`porous substrate 38 and forms a portion of the fuel passages
`65 50. Between the porous composite membrane 42 and the
`fuel plate 36 is a gasket 44. The gasket 44 is as known to a
`worker skilled in the art and prevents fuel from leaking and
`
`GE-1011.009
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`

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`US 6,709,492 Bl
`
`5
`
`6
`5
`deoxygenator 12 is related to permeability of the permeable
`from crossing over specific fuel passage defined by the fuel
`membrane 48 and the rate of diffusion through the surface of
`plate 46. In the preferred embodiment, the gasket 44 is
`the permeable membrane 48. The permeability of the per(cid:173)
`bonded to the membrane surface 48.
`meable membrane 48 is controlled by the solution of oxygen
`The fuel plate 46 defines the fuel passages 50 between the
`into the membrane and the diffusion of oxygen through it.
`inlet 26 and outlet 28. The fuel plate 46 only defines two
`The permeable membrane 48 must be of a specific thickness
`sides of each fuel passage 50 and the permeable composite
`in order to allow a desired diffusion of dissolved oxygen.
`membrane 42 defines the remaining sides of each fuel
`Preferably, the permeable membrane 48 is approximately
`passage 50. The configuration of the fuel passages 50 may
`four microns thick. Although a four-micron thick permeable
`be defined to assure that fuel is in maximum contact with the
`10 membrane 48 is used in the embodiment illustrated, it is also
`permeable composite membranes 42. One of ordinary skill
`understood that other thicknesses of permeable membrane
`in the art will recognize that the extent of contact between
`depending on application specific requirements are also
`the fuel and permeable composite membranes 42 required is
`within the contemplation of this invention. As one example,
`only the contact necessary to achieve the desired perfor(cid:173)
`permeable membranes 48 between 0.5 microns and 20
`mance and other levels of contact are within the scope of the
`15 microns are possible and within the scope of the invention.
`invention.
`The rate of diffusion of oxygen from the fuel through the
`The specific quantity of fuel plates 46, permeable com(cid:173)
`surface of the permeable membrane 48 is affected by the
`posite membranes 42 and porous plates 38 are determined
`duration of contact of fuel with the permeable membrane 48.
`by application-specific requirements, such as fuel type, fuel
`It is desirable, but not required, to keep a constant contact
`temperature, and mass flow demand from the engine.
`20 between the permeable membrane 48 and fuel in order to
`Further, different fuels containing differing amounts of dis(cid:173)
`maximize the amount of oxygen removed from the fuel.
`solved oxygen may require differing amounts of deoxygen(cid:173)
`Optimizing the amount of diffusion of dissolved oxygen
`ation to remove a desired amount of dissolved oxygen.
`requires a balance between maximizing fuel flow and fuel
`Further, applications specific requirements govern the spe(cid:173)
`temperature, and the creation of mixing to optimize contact
`cific number of porous plates 38 and permeable composite
`25 with the permeable membrane 48, as well as accounting for
`membranes 42.
`minimizing pressure loss and accounting for manufacturing
`Referring to FIG. 9, preferably each of the fuel plates 46
`tolerances and costs. Without mixing, only fuel flowing
`are manufactured with integrally formed fuel flow passages
`along the permeable membrane 48 would be stripped of
`that enhance contact between fuel and the permeable mem(cid:173)
`dissolved oxygen, leaving a large amount of dissolved
`brane 42. Enhancing contact between fuel flow and the
`30 oxygen in fuel flowing toward the center of the fuel passage
`permeable membrane optimizes mass transport of dissolved
`50. Dissolved oxygen contained in fuel flowing through the
`oxygen through the permeable composite membrane 42.
`center of the fuel passages 50, away from the permeable
`Improving the mass transport capacity allows for a reduction
`membrane 48, would not migrate out of the fuel. Therefore,
`in size of the deoxygenator 12 without a corresponding
`the fuel plate 46 enhances the diffusion of oxygen from the
`reduction in performance.
`35 bulk flow to the membrane surface 48 and significantly
`The fuel plate 46 includes an inlet 54 and an outlet 56. The
`reduces the fuel passage length or residence time required
`fuel passages 50 are formed to maximize fuel exposure to
`for removing more than 90 percent and preferably more than
`the permeable composite membrane 42. This may be accom(cid:173)
`97 percent of the dissolved oxygen, thereby suppressing
`plished by providing mixing and/or optimal flow patterns for
`coke deposition.
`the fuel. The fuel passages 50 are formed to maximize the 40
`The mixing members 52 disposed within the fuel passages
`amount of area of the fuel in contact with the permeable
`50 encourage mixing of the fuel such that significant por(cid:173)
`membrane in order to maximize the amount of dissolved
`tions of the fuel contact the permeable membrane 48 during
`oxygen removed from the fuel. The specific size of the fuel
`passage through the deoxygenator assembly 12. Although
`passage 50 must be of a size to allow the required amount
`mixing is advantageous to removing dissolved oxygen from
`of fuel flow and provide optimal contact with surfaces of the
`45 the fuel, turbulent flow produces an undesirable pressure
`permeable membrane 38. In other words, the fuel passages
`drop. Therefore, the mixing members 52 are configured to
`50 must be small enough that fuel is in contact with the
`produce a mixing effect without producing turbulent flow
`permeable membrane 42 and also must be large enough so
`effects. The mixing members 52 produce a mixing of the fuel
`as to not restrict fuel flow.
`that remains within the laminar flow range. Laminar flow
`Another factor that will influence the oxygen removal rate 50 through the deoxygenator 12 reduces pressure drop between
`is the fuel temperature. Fuel heating promotes oxygen
`the inlet 26 and outlet 28. Turbulent flow may also be used,
`diffusion and reduces oxygen solubility, thereby simulta(cid:173)
`in spite of pressure drop, when it provides the desired level
`neously enhancing mixing and increasing the driving force
`of mixing and an acceptable pressure loss. The mixing
`across the membrane. Therefore, in the preferred embodi(cid:173)
`members 52 extend transversely relative to the direction of
`ment the fuel is preheated to approximately 200 F prior to
`55 fuel flow indicated at 32 to cause the fuel to mix such that
`entry into the deoxygenator. For many fuels, such as JP-8,
`each portion of the fuel contacts the permeable membrane
`heating fuel above 200 F should be avoided because thermal
`48 in a uniform manner while flowing through the assembly
`oxidation (coking) will begin. The temperature at which
`12.
`thermal oxidation begins depends on the type of fuel,
`Referring to FIG. 11 another embodiment of the fuel plate
`impurities in the fuel, etc., and one of ordinary skill in the 60
`46 is shown including mixing members 52 extending trans(cid:173)
`art will recognize that the fuel may be heated to other
`versely from one side of the fuel plate 46. In this
`temperatures within the scope of the invention.
`embodiment, fuel flowing over the mixing members 52 is
`Referring to FIGS. 10 and 11, fuel flows through the flow
`encouraged to tumble and mix such that fuel more uniformly
`passages 50 in the direction indicated by the arrow 32. The
`contacts the permeable membrane 48. It should be under-
`fuel plate 46 includes multiple fuel mixing members 52 65
`stood that it is within the contemplation of this invention to
`disposed at alternating intervals along the flow passages 50
`include any configurations, shapes, sizes, etc. of mixing
`members 52 or mixing enhancers, be they inertial,
`to create a mixing effect in the fuel. Performance of the
`
`GE-1011.010
`
`

`
`US 6,709,492 Bl
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`5
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`50
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`7
`mechanical, acoustic or otherwise, to induce the desired
`amount of mixing according to application specific param(cid:173)
`eters.
`Referring to FIG. 10, in operation, fuels flowing through
`the fuel passages 50 in the direction of arrow 32 are caused
`to change direction and mix by the mixing members 52 and
`contact the permeable membrane 48. Vacuum creates an
`oxygen partial pressure differential between the inner walls
`of the fuel passage 50 and the porous membrane 42 which
`causes diffusion of oxygen dissolved within the fuel to
`migrate into the porous substrate 38 and out of the deoxy(cid:173)
`genator assembly 12 separate from the fuel flow 32. A result
`of the reduced oxygen content in the fuel is an increase in the
`thermal oxidative stability of the fuel that is manifested by
`a reduction of the formation of the objectionable deposits
`known as "coke". The increase in the temperature at which
`significant "coke" occurs increases the exploitable cooling
`capacity of the fuel. The cooling capacity of the fuel is rated
`in regard to the temperature at which auto-oxidation occurs
`to form coke deposits on the inner surfaces of fuel systems
`or engine components.
`Removing dissolved oxygen increases the exploitable
`cooling capacity allowing lower grades of fuel to operate at
`increased temperatures and to recover waste heat. This
`reduces fuel consumption costs associated with operation of
`an aircraft and further reduces maintenance requirements.
`Further, increased cooling capacity allows for operation of
`an engine at increased temperatures that in turn increases the
`overall efficiency of operating the engine. This invention
`provides the means of efficiently removing dissolved oxygen 30
`within fuel to increase thermal capacity thereby increasing
`engine operating efficiency.
`The foregoing description is exemplary and not just a
`material specification. The invention has been described in
`an illustrative manner, and should be understood that the
`terminology used is intended to be in the nature of words of
`description rather than of limitation. Many modifications
`and variations of the present invention are possible in light
`of the above teachings. The preferred embodiments of this 40
`invention have been disclosed, however, one of ordinary
`skill in the art would recognize that certain modifications are
`within the scope of this invention. It is understood that
`within the scope of the appended claims, the invention may
`be practiced otherwise than as specifically described. For
`that reason the following claims should be studied to deter(cid:173)
`mine the true scope and content of this invention.
`What is claimed is:
`1. A fuel deoxygenator assembly comprising:
`a housing comprising a fuel inlet and a fuel outlet;
`fuel plate defining fuel passages through said housing
`between said inlet and outlet;
`a permeable membrane supported by a porous substrate
`on a non-fuel side, said permeable membrane in contact
`with fuel flowing through said fuel passages on a fuel 55
`side;
`at least one opening within said housing in communica(cid:173)
`tion with said porous substrate for creating an oxygen
`partial pressure differential between said fuel side and
`said non-fuel side of said permeable membrane to draw 60
`dissolved oxygen out of fuel within said fuel passages.
`2. The assembly of claim 1, further comprising a poly(cid:173)
`tetrafluoroethylene coating disposed on said fuel side of said
`permeable membrane.
`
`8
`3. The assembly of claim 1, further comprising a perflu(cid:173)
`orinated glassy polymer disposed on said fuel side of said
`permeable membrane.
`4. The assembly of claim 1, further comprising a polyper-
`fluorobutenyl vinyl ether disposed on said fuel side of said
`permeable membrane.
`5. The assembly of claim 1, comprising a vacuum source
`for providing a vacuum at said at least one opening for
`providing said oxygen partial pressure differential between
`10 said fuel passages and said porous substrate.
`6. The assembly of claim 1, further comprising a second
`opening for a flow of strip gas through said housing in
`communication with said porous substrate creating said
`15 oxygen partial pressure differential.
`7. The assembly of claim 1, wherein said fuel plate defines
`two sides of said fuel passages.
`8. The assembly of claim 7, wherein said fuel plate
`includes a plurality of members extending between said
`20 sides of said fuel passages to induce mixing of fuel flowing
`through said fuel passages.
`9. The assembly of claim 7, wherein said fuel plate
`includes an inlet portion and an outlet portion.
`10. The assembly of claim 1, wherein said fuel plate is
`25 sandwiched between two of said permeable membranes such
`that said permeable membrane forms a portion of said fuel
`passages.
`11. The assembly of claim 1, further comprising a plu(cid:173)
`rality of said fuel plates sandwiched between a correspond(cid:173)
`ing plurality of said permeable membranes disposed within
`said housing forming a plurality of said fuel passages.
`12. The assembly of claim 11, wherein each porous
`substrate is sandwiched between said permeable
`35 membranes, and each fuel plate is sandwiched between said
`permeable membranes.
`13. The assembly of claim 1, wherein said permeable
`membrane comprises a polytetrafluoroethylene amorphous
`fluoropolymer.
`14. The assembly of claim 1, wherein