Multi level injector for chemical vapor infiltration reactor

Abstract

A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, at least one inlet for receiving a flow of reactive gas, at least one outlet for exhausting the flow of reactive gas, a plurality of vertically stacked plates defining a plurality of levels, and at least one dedicated fluid pathway for transporting the flow of reactive gas, the at least one dedicated fluid pathway extending from the at least one inlet and including a plurality of injector ports within each level of the plurality of levels.

Description

[0001] MULTI LEVEL INJECTOR FOR CHEMICAL VAPOR INFILTRATION REACTOR

[0002] CROSS-REFERENCE TO RELATED APPLICATION(S)

[0003] This application claims the benefit of U.S. Provisional Application No. 63 / 551,761 filed February 9, 2024 for “MULTI LEVEL INJECTOR FOR CHEMICAL VAPOR INFILTRATION REACTOR” by J. Nable, Y. She, J. Banhos, B. Lenz, J. Kavosi, A. Bazshushtari, and W. Beeson; and U.S Provisional Application No. 63 / 696,836 filed September 19, 2024 for “UNIFORMLY COATING POROUS COMPOSITE MATERIALS” by O. Sudre, B. Lenz, E. Callaway, J. Nable, Y. She, and J. Kavosi.

[0004] BACKGROUND

[0005] The present invention relates generally to chemical vapor infiltration, and more particularly to systems for carrying out chemical vapor infiltration.

[0006] Chemical vapor infiltration (CVI) is a well-known process used in the fabrication of ceramic matrix composites (CMCs). During CVI, one or more porous ceramic preforms can be placed in a reactor and exposed to reactive precursors carried in a gaseous flow through the reactor. Many reactors are designed such that gas flows in through only one end (i.e., the inlet end) of the reactor and travels to the opposite end (i.e., the outlet end) of the reactor. With such designs, reactive precursors within the gas tend to deplete toward the outlet end of the reactor due to consumption from the deposition reaction, thus deposits on downstream preforms (i.e., those further from the inlet end) tend to be thinner than deposits on upstream preforms. To ensure a more uniform coating, the CVI process can be interrupted to reverse the location of preforms within the reactor, however, more efficient means of ensuring uniform deposition are desirable.

[0007] SUMMARY

[0008] A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, at least one inlet for receiving a flow of reactive gas, at least one outlet for exhausting the flow of reactive gas, a plurality of vertically stacked plates defining a plurality of levels, and at least one dedicated fluid pathway for transporting the flow of reactive gas, the at least one dedicated fluid pathway extending from the at least one inlet and including a plurality of injector ports within each level of the plurality of levels. A method of performing chemical vapor infiltration (CVI) includes placing a fibrous preform upon each of a plurality of vertically stacked plates within a reactor, the vertically stacked plates defining a plurality of levels, and providing a flow of a reactive gas to each of the plurality of levels using at least one dedicated fluid pathway extending through each of the plurality of levels, the dedicated fluid pathway comprising a plurality of injector ports within each of the plurality of levels for injecting an amount of the flow of reactive gas into each of the plurality of levels.

[0009] A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, at least one inlet for receiving a flow of reactive gas, at least one outlet for exhausting the flow of reactive gas, a plurality of vertically stacked plates defining a plurality of levels, and a plurality of dedicated fluid pathways for transporting the flow of reactive gas to each of the plurality of levels, the plurality of dedicated fluid pathways extending from the at least one inlet and each comprising a plurality of injector ports within each level of the plurality of levels.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS

[0011] FIG. l is a schematic illustration of a CVI reactor.

[0012] FIG. 2 is a schematic illustration of a first alternative embodiment of the CVI reactor.

[0013] FIG. 3 is a schematic illustration of a second alternative embodiment of the CVI reactor.

[0014] FIG. 4 is a schematic illustration of a third alternative embodiment of the CVI reactor.

[0015] While the above-identified figures set forth one or more embodiments of the present disclosure, other embodiments are also contemplated, as noted in the discussion. In all cases, this disclosure presents the invention by way of representation and not limitation. It should be understood that numerous other modifications and embodiments can be devised by those skilled in the art, which fall within the scope and spirit of the principles of the invention. The figures may not be drawn to scale, and applications and embodiments of the present invention may include features and components not specifically shown in the drawings.

[0016] DETAILED DESCRIPTION

[0017] This disclosure presents various CVI reactors with targeted delivery of vaporous reactants to individual reactor levels via multi-level injector ports allowing for a more refined CVI cycle using targeted delivery of reactive gases throughout the reactor. FIG. 1 is a schematic illustration of CVI reactor 10. Reactor 10 includes body 12 defining an inner volume 14. Reactor 10 further includes inlet 16 for receiving a flow of reactive gas, indicated by arrows, from one or more gas sources (not shown), and outlet 18 for exhausting the flow of gas from inner volume 14. A vacuum source can be in communication with outlet 18 for drawing the flow of reactive gas from inner volume 14. The flow of reactive gas can include a reactive precursor and a process / carrier gas which are combined to form the reactive gas. Support plates 20 can partition inner volume 14 into multiple (e.g., two to ten) vertically stacked levels (or stages) 22. Preheating and / or premixing zone 24 can optionally be disposed between inlet 16 and a first plate 20 for heating the incoming flow of reactive gas to a desired temperature. One or more preforms 26 (e.g., fibrous ceramic preforms) can be supported by plate 20 within a respective level 22.

[0018] Reactor 10 can include a dedicated pathway for the flow of reactive gas extending from inlet 16. In the embodiment shown in FIG. 1, such pathway can be arranged as a generally centrally disposed hollow tube 28, which can be cylindrical or other suitable hollow shape. Tube 28 can include one or more injector ports 30 within each level 22 for supplying / injecting an amount of the flow of reactive gas to preforms 26 of a respective level 22. In this way, tube 28 acts as a manifold for the reactive gas flow. Injector ports 30 may be disposed circumferentially about tube 28 in some embodiments. Tube 28 allows a dedicated flow of generally unreacted reactive gas to preforms 26 within each level 22 and facilitates a more uniform infiltration and / or deposition across all preforms 26 within reactor 10. This is in contrast with conventional designs in which reactive gas is introduced to a reactor inner volume and diffuses through holes in support plates 20 in the upstream to downstream direction. It should be noted that plates 20 can still include such holes in the embodiments discussed herein to, for example, allow for gaseous byproducts to be exhausted from levels 22 via outlet 18. Injector ports 30 can be varied from one level 22 to another to account for reaction kinetics and other variables typically influencing uniform deposition. As used herein, “deposition” can refer to formation of a matrix or the formation of individual coatings (e.g., interface coatings). For example, deposition can occur more quickly on upstream substrates based on proximity to the incoming flow of reactive gas. Further, reactants which do not deposit on upstream substrates can otherwise prematurely react and / or decompose before reaching downstream substrates. As such, injector ports 30 in fluid communication with downstream levels 22 can be varied compared to those in upstream levels 22. In one example, a downstream level 22 can include more injector ports 30 as compared to the immediate upstream level 22 and / or the upstream -most level 22. As another example, the geometry and / or dimensions of injector ports 30 in a downstream level 22 can be varied (e.g., made larger) to allow for a relatively greater mass flow of reactive gas into said downstream level 22 in an effort to ensure more uniform deposition in a given amount of time between upstream preforms 26 and downstream preforms 26.

[0019] FIG. 2 is a schematic illustration of CVI reactor 110 which is substantially similar to reactor 10, having body 112 defining inner volume 114, inlet(s) 116, outlet 118, optional preheating and / or premixing zone 124, and support plates 120 for supporting preforms 126 and forming multiple levels 122 within inner volume 114. Reactor 110 differs in that it includes multiple tubes 128 through which the flow of reactive gas can be delivered to levels 122. As shown, tubes 128 can be arranged on the periphery of reactor 110 close to body 112. Each tube 128 can be in fluid communication with and extend from inlet 116, which, although represented as multiple distinct inlets 116, can be a common inlet 116 in an alternative embodiment. Each tube 128 similarly includes injector ports 130 in fluid communication with each level 122. Such injector ports 130 can be varied in any manner discussed above with respect to reactor 10. The multiple peripheral tubes 128 of reactor 110 can be preferable for increased delivery of reactive gases compared to a single tube embodiment (i.e., reactor 10), although either tube 128 can be selectively operable in a manner similar to a single tube embodiment depending on, for example, the number and / or geometry of preforms 126 to be infiltrated. In an alternative embodiment in which reactor 110 includes a retort (not shown), dedicated peripheral pathways 128 can be configured between body 112 and the retort walls, with injector ports formed in the retort walls at each level 122. This may be a preferable method of retrofitting in some reactor designs.

[0020] FIG. 3 is a schematic illustration of CVI reactor 210 which combines elements of reactors 10 and 110, having both a central and peripheral tubes 228. As with reactors 10 and 110, body 212 defines inner volume 214, while plates 220 partially define preheating and / or premixing zone 224 and multiple levels 222. Each tube 228 can be in fluid communication with a dedicated or common inlet 216. Gas can be exhausted via outlet 218. Injector ports 230 are formed in each tube 228 within each level 222, and a variable from level to level as discussed above. Peripheral tubes 228 can alternatively be arranged as a flow path between body 212 and a reactor retort, as discussed above with respect to reactor 110. The embodiment depicted in FIG. 3 can be preferable for directing the flow of reactive gas to multiple surfaces (i.e., left and right based on the orientation of FIG. 3) of each preform 226 via the central and peripheral injector ports 230. Such arrangement can facilitate a more uniform deposition on a preform-by-preform basis, in addition to the uniformity of deposition achieved across all preforms 226 from the targeted delivery of reactive gases to each level 222.

[0021] FIG. 4 is a schematic illustration of CVI reactor 310 is similar to reactor 210, having both a central and peripheral tubes 328. As with reactors 10, 110, and 210, body 312 defines inner volume 314, while plates 320 partially define preheating and / or premixing zone 324 and multiple levels 322. Peripheral tubes 328 can be in direct fluid communication with a common or dedicated inlets 316 for delivering the flow of reactive gas to levels 322 via injector ports 328. Unlike the previous embodiments, centrally disposed tube 328 can be configured as a dedicated exhaust pathway for drawing gas flow from each level 322. As such, centrally disposed tube 328 can be in direct fluid communication with outlet 318, and its respective ports can be exhaust ports 332 rather than injector ports 330. Peripheral tubes 328 can be in indirect fluid communication with outlet 318 via centrally disposed tube 328, and centrally disposed tube 328 can therefore be in indirect fluid communication with inlet(s) 316 via peripheral tubes 328. The embodiment depicted in FIG. 4 can advantageously help to exhaust reaction byproducts (e.g., gaseous HC1) from levels 322 more efficiently than other designs, helping to mitigate the “poisoning effect” of excess HC1 build-up on / around preforms 326.

[0022] In some embodiments, a foam or high surface area media can be provided in inlet(s) tube(s) 28, 128, 228, 328 (for example, in premixing zone 24, 124, 224, 324) in to initiate decomposition of reactant precursors of the CVI reactant gas and generate a byproduct that promote more uniform deposition of matrix material in preforms 26, 126, 226, 326, as described in U.S. Provisional Application No. 63 / 696,836, which is incorporated by reference in its entirety. In at least one embodiment, the matrix precursor gas may comprise methyltrichlorosilane, dimethylchlorosilane, silicon tetrachloride combined with methane, and combinations thereof. Upon decomposition, methyltrichlorosilane forms one silicon carbide (SiC) atom and three hydrochloric acid atoms. SiC may act as the matrix material, while hydrochloric acid may act as the poisoning molecule, which can inhibit deposition of silicon carbide, particularly at external portions of the preforms and thereby preventing the rapid closure of pore paths to the interior of preforms. Increasing the concentration of the hydrochloric acid byproduct in the reactant gas in tubes 28, 128, 228, 328 (prior to reaching preforms 26, 126, 226, 326) can result in more uniform deposition of matrix material (SiC) throughout the preforms. The foam or high surface area media a carbon foam, e.g., a reticulated vitreous carbon foam, a carbon preform, a carbon felt, a sacrificial fibrous preform, or combinations thereof. The sacrificial fibrous preform may comprise the same materials as the preforms 26, 126, 226, 326. The foam or high surface area media can have a surface area sufficient to generate an amount of poisoning molecule that is sufficient to poison the reaction on preforms 26, 126, 226, 326.

[0023] The disclosed CVI reactors with dedicated flow pathways can be used when infiltrating preforms via CVI, to deposit interface coatings (e.g., layers of BN, SiC, Si- doped BN, etc.) and / or to form a matrix (e.g., SiC) to create a CMC component. Such CMC components can be incorporated into aerospace, maritime, or industrial equipment, to name a few, non-limiting examples.

[0024] Discussion of Possible Embodiments

[0025] The following are non-exclusive descriptions of possible embodiments of the present invention.

[0026] A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, at least one inlet for receiving a flow of reactive gas, at least one outlet for exhausting the flow of reactive gas, a plurality of vertically stacked plates defining a plurality of levels, and at least one dedicated fluid pathway for transporting the flow of reactive gas, the at least one dedicated fluid pathway extending from the at least one inlet and including a plurality of injector ports within each level of the plurality of levels.

[0027] The reactor of the preceding paragraph can optionally include, additionally and / or alternatively, any one or more of the following features, configurations and / or additional components:

[0028] In the above reactor, the at least one dedicated fluid pathway can include a tube.

[0029] In any of the above reactors, the plurality of injector ports within one level of the plurality of levels can be greater in number than the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

[0030] In any of the above reactors, each of the plurality of injector ports within one level of the plurality of levels can have a larger dimension than each of the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

[0031] In any of the above reactors, the tube can be centrally disposed within the reactor.

[0032] In any of the above reactors, the at least one dedicated fluid pathway can include a plurality of tubes.

[0033] In any of the above reactors, two of the plurality of tubes can be oppositely disposed on a periphery of the reactor. In any of the above reactors, one of the plurality of tubes can be centrally disposed within the reactor.

[0034] In any of the above reactors, the one of the plurality of tubes can include a plurality of injector ports within each level of the plurality of levels for injecting the flow of reactive gas into each of the plurality of levels.

[0035] In any of the above reactors, the one of the of the plurality of tubes can include a plurality of exhaust ports within each level of the plurality of levels for exhausting the flow of reactive gas from each of the plurality of levels.

[0036] Any of the above reactors can further include at least one fibrous preform supported by a respective plate of the plurality of vertically stacked plates.

[0037] A method of performing chemical vapor infiltration (CVI) includes placing a fibrous preform upon each of a plurality of vertically stacked plates within a reactor, the vertically stacked plates defining a plurality of levels, and providing a flow of a reactive gas to each of the plurality of levels using at least one dedicated fluid pathway extending through each of the plurality of levels, the dedicated fluid pathway comprising a plurality of injector ports within each of the plurality of levels for injecting an amount of the flow of reactive gas into each of the plurality of levels.

[0038] The method of the preceding paragraph can optionally include, additionally and / or alternatively, any one or more of the following features, configurations and / or additional steps:

[0039] In the above method, the at least one dedicated fluid pathway can include a tube.

[0040] In any of the above methods, the plurality of injector ports within in one level of the plurality of levels can be greater in number than the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

[0041] In any of the above methods, each of the plurality of injector ports within one level of the plurality of levels can have a larger dimension than each of the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

[0042] A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, at least one inlet for receiving a flow of reactive gas, at least one outlet for exhausting the flow of reactive gas, a plurality of vertically stacked plates defining a plurality of levels, and a plurality of dedicated fluid pathways for transporting the flow of reactive gas to each of the plurality of levels, the plurality of dedicated fluid pathways extending from the at least one inlet and each comprising a plurality of injector ports within each level of the plurality of levels. The reactor of the preceding paragraph can optionally include, additionally and / or alternatively, any one or more of the following features, configurations and / or additional components:

[0043] In the above reactor, each of the plurality of dedicated fluid pathways can include a tube.

[0044] In any of the above reactors, two of the plurality tubes can be oppositely disposed on a periphery of the reactor.

[0045] In any of the above reactors, one of the plurality of tubes can be centrally disposed within the reactor.

[0046] In any of the above reactors, the one of the plurality of tubes can include a plurality of exhaust ports within each level of the plurality of levels for exhausting the flow of reactive gas from each of the plurality of levels.

[0047] While the invention has been described with reference to an exemplary embodiment s), it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the scope of the invention. In addition, many modifications may be made to adapt a particular situation or material to the teachings of the invention without departing from the essential scope thereof. Therefore, it is intended that the invention not be limited to the particular embodiment(s) disclosed, but that the invention will include all embodiments falling within the scope of the appended claims.

Claims

CLAIMS:

1. A chemical vapor infiltration (CVI) reactor comprising: a body defining an internal volume; at least one inlet for receiving a flow of reactive gas; at least one outlet for exhausting the flow of reactive gas; a plurality of vertically stacked plates defining a plurality of levels; and at least one dedicated fluid pathway for transporting the flow of reactive gas, the at least one dedicated fluid pathway extending from the at least one inlet and comprising a plurality of injector ports within each level of the plurality of levels.

2. The reactor of claim 1, wherein the at least one dedicated fluid pathway comprises a tube.

3. The reactor of claim 2, wherein the plurality of injector ports within one level of the plurality of levels is greater in number than the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

4. The reactor of claim 2, wherein each of the plurality of injector ports within one level of the plurality of levels has a larger dimension than each of the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

5. The reactor of claim 2, wherein the tube is centrally disposed within the reactor.

6. The reactor of claim 5, wherein the at least one dedicated fluid pathway comprises a plurality of tubes.

7. The reactor of claim 6, wherein two of the plurality of tubes are oppositely disposed on a periphery of the reactor.

8. The reactor of claim 7, wherein one of the plurality of tubes is centrally disposed within the reactor.

9. The reactor of claim 8, wherein the one of the plurality of tubes comprises a plurality of injector ports within each level of the plurality of levels for injecting the flow of reactive gas into each of the plurality of levels.

10. The reactor of claim 8, wherein the one of the of the plurality of tubes comprises a plurality of exhaust ports within each level of the plurality of levels for exhausting the flow of reactive gas from each of the plurality of levels.

11. The reactor of claim 1 and further comprising: at least one fibrous preform supported by a respective plate of the plurality of vertically stacked plates.

12. A method of performing chemical vapor infiltration (CVI), the method comprising: placing a fibrous preform upon each of a plurality of vertically stacked plates within a reactor, the vertically stacked plates defining a plurality of levels; and providing a flow of a reactive gas to each of the plurality of levels using at least one dedicated fluid pathway extending through each of the plurality of levels, the dedicated fluid pathway comprising a plurality of injector ports within each of the plurality of levels for injecting an amount of the flow of reactive gas into each of the plurality of levels.

13. The method of claim 12, wherein the at least one dedicated fluid pathway comprises a tube.

14. The method of claim 13, wherein the plurality of injector ports within in one level of the plurality of levels is greater in number than the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

15. The reactor of claim 13, wherein each of the plurality of injector ports within one level of the plurality of levels has a larger dimension than each of the plurality of injector ports within a more fluidly upstream level of the plurality of levels.

16. A chemical vapor infiltration (CVI) reactor comprising: a body defining an internal volume; at least one inlet for receiving a flow of reactive gas; at least one outlet for exhausting the flow of reactive gas; a plurality of vertically stacked plates defining a plurality of levels; and a plurality of dedicated fluid pathways for transporting the flow of reactive gas to each of the plurality of levels, the plurality of dedicated fluid pathways extending from the at least one inlet and each comprising a plurality of injector ports within each level of the plurality of evels.

17. The reactor of claim 16, wherein each of the plurality of dedicated fluid pathways comprises a tube.

18. The reactor of claim 17, wherein two of the plurality tubes are oppositely disposed on a periphery of the reactor.

19. The reactor of claim 18, wherein one of the plurality of tubes is centrally disposed within the reactor.

20. The reactor of claim 19, wherein the one of the plurality of tubes comprises a plurality of exhaust ports within each level of the plurality of levels for exhausting the flow of reactive gas from each of the plurality of levels.

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