Chemical vapor infiltration gas inlet injector plate

Abstract

A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, an inlet for receiving a flow of reactive gas, an outlet for exhausting the flow of reactive gas, a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet, and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates including at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway, and a plurality of holes extending from the at least one channel to a surface of the plate.

Description

[0001] CHEMICAL VAPOR INFILTRATION GAS INLET INJECTOR PLATE

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

[0003] This application claims the benefit of U.S. Provisional Application No. 63 / 551,755 filed February 9, 2024 for “CHEMICAL VAPOR INFILTRATION GAS INLET INJECTOR PLATE” by J. Nable, Y. She, J. Banhos, 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, an inlet for receiving a flow of reactive gas, an outlet for exhausting the flow of reactive gas, a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet, and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates including at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway, and a plurality of holes extending from the at least one channel to a surface of the plate. A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, an inlet for receiving a flow of reactive gas, an outlet for exhausting the flow of reactive gas, a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet, and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates including at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway, and a plurality of holes extending from the at least one channel to a surface of the plate. A first plurality of holes in a first plate are different from a second plurality of holes in a second plate.

[0009] A method of performing 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 by flowing the reactive gas through a dedicated fluid pathway extending from an inlet of the reactor, and flowing an amount of the reactive gas through at least one channel formed in each of the plurality of plates, then through a plurality of holes extending from the at least one channel to an outer surface of each of the plurality of plates.

[0010] BRIEF DESCRIPTION OF THE DRAWINGS

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

[0012] FIG. 2A is a schematic top view of a plate for the CVI reactor according to a first embodiment.

[0013] FIG. 2B is a schematic top view of a plate for the CVI reactor according to a second embodiment.

[0014] FIG. 3 is a schematic illustration comparing holes from plates in first and second levels 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 a CVI reactor with targeted delivery of vaporous reactants to individual reactor levels via channels within the support plates allowing for a more refined CVI cycle.

[0018] 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 (i.e., along the y-axis) stages / levels 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.

[0019] Reactor 10 can include a dedicated pathway for the flow of reactive gas extending along the y-axis from inlet 16. In the embodiment shown in FIG. 1, such pathway can be arranged as a centrally disposed hollow tube 28, which can be cylindrical or other suitable hollow shape. Disposed within each plate 20 is at least one channel 30 extending generally orthogonal to (i.e., along the x-axis) and in direct fluid communication with tube 28. Each channel 30 can further be in direct fluid communication with at least one hole 32, each of which extends upward along the y-axis to outer surface 34 of a respective plate 20, supplying / injecting an amount of the flow of reactive gas to preforms 26 of a respective level 22. In this way, tube 28, channels 30, and holes 32 act as a manifold for the flow of reactive gas. Tube 28 can be fluidly sealed at its end opposite inlet 16 to help direct the flow of reactive gas into channels 30.

[0020] In some embodiments, a foam or high surface area media can be provided in channels 30 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, 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 channels 30 (prior to reaching preforms 26) 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. 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.

[0021] FIGS. 2A and 2B are top views of plates 20A and 20B for a CVI reactor (e.g., reactor 10). Referring first to FIG. 2A, multiple individual channels 30A, represented with dashed lines as within the thickness of plate 20A, extend radially from tube 28A. Although four channels 30A are shown, fewer than four or more than four are possible in alternative embodiments. Each channel 30A can be in fluid communication with multiple holes 32A. Preforms 26 (see FIG. 1; not shown in FIG. 2A) can be positioned to overlap with channels 30A and holes 32A, or to be disposed between channels 30A. In FIG. 2B, a single channel 30B is formed within plate 20B. Channel 30B can be formed by machining material from disc-like halves of plate 20B such that, when secured together, a hollowed-out area (i.e., channel 30B) is formed. Holes 32B can be variously arranged within plate 20B to be aligned and in fluid communication with channel 3 OB. Although shown with a circular geometry like plate 20B, channel 30B need not have the same geometry as plate 20B. Further, plates 20A and / or 20B need not be circular, but can be elliptical or have straight sides in alternative embodiments.

[0022] Referring back to FIG. 1, holes 32 can be varied from level to level to account for reaction kinetics and other variables typically influencing uniform deposition on preforms 26 of different levels. 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 preforms 26 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. Deposition variability can be addressed by controlling the amount of reactive gas supplied to each level to create a more even rate of deposition across all levels 22. This can be accomplished by, for example, providing more holes 32 in downstream levels 22 than in upstream levels 22 to allow for a greater mass flow to downstream levels. Holes 32 can additionally and / or alternatively be geometrically and / or dimensionally varied. FIG. 3 is a schematic illustration comparing holes 32 from different levels 22 having different dimensions. More specifically, hole 32-1 can be from a first level, for example, the upstream-most level (i.e., closest to inlet 16). Hole 32-2 can be from a second level, for example, the downstream-most level (i.e., closest to outlet 18). For circular geometries, as shown in FIG. 3, hole 32-1 can have a first radius R1 and hole 32-2 can have a second radius R2 which is larger than Rl. This can be true for one or more holes 32-1 and 32-2. For non-circular geometries, Rl and R2 can represent other dimensions (e.g., semi-major or semi-minor axes for ellipses). Additional intermediate levels can have holes with the same dimensions as hole 32-1 or holes 32-2, or different dimensions, based on the desired process parameters. Software modeling can be used to determine the ideal number, geometry, and dimension of holes 32, as well as channel 30 characteristics for each level 22 to allow for finer flow control at each level 22.

[0023] The disclosed CVI reactor 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, an inlet for receiving a flow of reactive gas, an outlet for exhausting the flow of reactive gas, a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet, and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates including at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway, and a plurality of holes extending from the at least one channel to a surface of the plate.

[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, each of a first plurality of holes in a first plate can have a first dimension, and each of a second plurality of holes in a second plate can have a second dimension larger than the first dimension. In any of the above reactors, a first plurality of holes in a first plate can be greater than a second plurality of holes in a second plate.

[0029] In any of the above reactors, each of the plurality of holes can be circular.

[0030] In any of the above reactors, at least one dedicated fluid pathway can be a tube.

[0031] In any of the above reactors, the at least one channel can include a plurality of channels.

[0032] Any of the above reactors can further include a preheating zone upstream of a first level of the plurality of levels.

[0033] In any of the above reactors, the dedicated flow pathway can extend along a first axis.

[0034] In any of the above reactors, the at least one channel can extend along a second axis.

[0035] In any of the above reactors, the at least one of the plurality of holes can extend from the at least one channel along the first axis.

[0036] A chemical vapor infiltration (CVI) reactor includes a body defining an internal volume, an inlet for receiving a flow of reactive gas, an outlet for exhausting the flow of reactive gas, a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet, and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates including at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway, and a plurality of holes extending from the at least one channel to a surface of the plate. A first plurality of holes in a first plate are different from a second plurality of holes in a second plate.

[0037] 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:

[0038] In the above reactor, each of the first plurality of holes can have a first dimension, and each of the second plurality of holes can have a second dimension larger than the first dimension.

[0039] In any of the above reactors, the first plurality of holes can be greater than the second plurality of holes.

[0040] In any of the above reactors, each of the first plurality of holes or the second plurality of holes can be circular.

[0041] In any of the above reactors, the at least one dedicated fluid pathway can be a tube.

[0042] In any of the above reactors, the at least one channel can include a plurality of channels. Any of the above reactors can further include a preheating zone upstream of a first level of the plurality of levels.

[0043] A method of performing 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 by flowing the reactive gas through a dedicated fluid pathway extending from an inlet of the reactor, and flowing an amount of the reactive gas through at least one channel formed in each of the plurality of plates, then through a plurality of holes extending from the at least one channel to an outer surface of each of the plurality of plates.

[0044] 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:

[0045] In the above method, each of a first plurality of holes in a first plate can have a first dimension, and each of a second plurality of holes in a second plate can have a second dimension larger than the first dimension.

[0046] In any of the above methods, a first plurality of holes in a first plate can be greater than a second plurality of holes in a second plate.

[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; an inlet for receiving a flow of reactive gas; an outlet for exhausting the flow of reactive gas; a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet; and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates comprising: at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway; and a plurality of holes extending from the at least one channel to a surface of the plate.

2. The reactor of claim 1, wherein each of a first plurality of holes in a first plate have a first dimension, and wherein each of a second plurality of holes in a second plate have a second dimension larger than the first dimension.

3. The reactor of claim 1, wherein a first plurality of holes in a first plate is greater than a second plurality of holes in a second plate.

4. The reactor of claim 1, wherein each of the plurality of holes is circular.

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

6. The reactor of claim 1 , wherein the at least one channel comprises a plurality of channels.

7. The reactor of claim 1 and further comprising: a preheating zone upstream of a first level of the plurality of levels.

8. The reactor of claim 1, wherein the dedicated flow pathway extends along a first axis.

9. The reactor of claim 8, wherein the at least one channel extends along a second axis.

10. The reactor of claim 9, wherein the at least one of the plurality of holes extends from the at least one channel along the first axis.

11. A chemical vapor infiltration (CVI) reactor comprising: a body defining an internal volume; an inlet for receiving a flow of reactive gas;an outlet for exhausting the flow of reactive gas; a dedicated fluid pathway for transporting the flow of reactive gas extending from the inlet; and a plurality of vertically stacked plates defining a plurality of levels, each of the plurality of plates comprising: at least one channel disposed within the plate and in fluid communication with the dedicated fluid pathway; and a plurality of holes extending from the at least one channel to a surface of the plate, wherein a first plurality of holes in a first plate are different from a second plurality of holes in a second plate.

12. The reactor of claim 11, wherein each of the first plurality of holes have a first dimension, and wherein each of the second plurality of holes have a second dimension larger than the first dimension.

13. The reactor of claim 11, wherein the first plurality of holes is greater than the second plurality of holes.

14. The reactor of claim 11, wherein each of the first plurality of holes or the second plurality of holes is circular.

15. The reactor of claim 11, wherein the at least one dedicated fluid pathway is a tube.

16. The reactor of claim 11, wherein the at least one channel comprises a plurality of channels.

17. The reactor of claim 11 and further comprising: a preheating zone upstream of a first level of the plurality of levels.

18. A method of performing 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 by: flowing the reactive gas through a dedicated fluid pathway extending from an inlet of the reactor; and flowing an amount of the reactive gas through at least one channel formed in each of the plurality of plates, then through aplurality of holes extending from the at least one channel to an outer surface of each of the plurality of plates.

19. The method of claim 18, wherein each of a first plurality of holes in a first plate have a first dimension, and wherein each of a second plurality of holes in a second plate have a second dimension larger than the first dimension.

20. The reactor of claim 18, wherein a first plurality of holes in a first plate is greater than a second plurality of holes in a second plate.

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