METHOD OF FABRICATING A REACTION CHAMBER FOR A FUEL STORAGE ASSEMBLY
A method for manufacturing a reaction chamber comprising a fuel insert and an elastic enclosure with a body and an opening, the method including the steps of stretching the body of the elastic enclosure to define a working lumen, orienting the metal hydride insert within the working lumen, and restituting the elastic enclosure over the insert.
This application claims the benefit of U.S. Provisional Application No. 61/400,412, filed 26 Jul. 2010, which is incorporated in its entirety by this reference.
TECHNICAL FIELDThis invention relates generally to the reaction chamber field, and more specifically to a new and useful method of manufacturing a reaction chamber in the reaction chamber field.
BACKGROUNDIn fuel generation systems, stable and repeatable performance for both continuous and on/off operation are highly desirable. Stable fuel generation from fuel carriers relies on how well a uniform and constant reaction interface is maintained between a fuel carrier and liquid reactant. In conventional systems, this reaction control is achieved by utilizing a liquid fuel carrier and pumping a designated amount of the fuel carrier to catalysts. However, solution type fuel carriers are less favored due to their low energy density. While solid fuel carriers have higher energy densities than liquid solutions, their further development has been hampered by difficulty in achieving reliable reaction control. The reaction control of a solid fuel carrier system relies on both the pumping rate of liquid reactants and the size of a reaction interface. In practical cases, volatile hydrolysis reaction at the interface leaves cavities or voids when the generated products flow away from the interface. This results in a non-contact between a fuel surface and liquid delivery medium such as a nozzle or wick. When this occurs, the performance of hydrogen generation system degrades over time. Furthermore, the performance of the fuel system becomes unpredictable when it is restarted after a stop period from the previous run. Typically, when the fuel system is investigated after its operation for a certain period, large gaps or voids are observed between the non-reacted surface of the solid fuel and the liquid delivery mechanism (LDM) such as a nozzle, wick, or membrane. This lack of control in maintaining constant and intact boundary between a solid fuel and liquid delivery medium has been the largest obstacle to achieving reliable performance of a solid fuel system.
Thus, there is a need in the fuel generator field to create a new and useful reaction chamber. This invention provides such new and useful reaction chamber.
The following description of the preferred embodiments of the invention is not intended to limit the invention to these preferred embodiments, but rather to enable any person skilled in the art to make and use this invention.
The method for manufacturing a reaction chamber comprises the steps of stretching the body of an elastic enclosure to define a working lumen S200; orienting a fuel insert within the working lumen S300; and, restituting the elastic enclosure over the insert S400. This method preferably utilizes an elastic enclosure and a fuel insert. The method preferably produces a reaction chamber with the elastic enclosure disposed substantially around the fuel insert, such that the elastic enclosure is in tension about the insert and applies a compressive force to the insert. The reaction chamber is preferably used to contain and control a fuel-generating reaction, more preferably a hydrogen-generating reaction. In operation, the elastic enclosure maintains contact between a liquid reagent delivery mechanism and a reaction zone, wherein the reaction zone is preferably the surface of the unreacted fuel insert. To address the issues described above, the reaction chamber of the preferred embodiments provides a moving boundary interface (i.e. the elastic enclosure) that ensures constant contact between a solid fuel insert and the liquid delivery mechanism and/or the liquid reagent by bringing the liquid delivery mechanism and/or the liquid reagent in contact with the varying contour of the reacting surface of the fuel insert. When the fuel insert is consumed and decreases in volume, the elastic enclosure shrinks and maintains substantially continuous contact with the insert surface. The assembled reaction chamber is preferably substantially similar to the reaction chamber disclosed in U.S. application Ser. No. 12/460,794, filed Jul. 23, 2009, incorporated herein by this reference. However, the assembled reaction chamber may be any suitable elastic reaction chamber that may facilitate volume exchange with the reaction products and/or collector. The method is preferably automated and performed by machinery using one or more machines, but may alternately be performed by hand, utilizing one or more assembly personnel.
The elastic enclosure 100 of the reaction chamber functions to apply a compressive force about substantially the whole of the fuel insert. As shown in
The fuel insert 200 functions to store fuel and to provide a reaction interface. This reaction interface is preferably along the surface of the fuel insert, and is preferably constantly changing as the insert is consumed by the reaction. The fuel insert preferably forms fuel upon reaction with a liquid reagent, and preferably forms hydrogen gas but may alternatively form any suitable fuel (e.g. methane, butane, etc.). The fuel insert preferably comprises a metal hydride fuel carrier, more preferably sodium borohydride (SBH) fuel carrier, but may alternately include lithium borohydride, alane, or any other suitable fuel carrier. The fuel insert preferably comprises metal hydride powder compressed into a solid insert (e.g. pill), but may alternately comprise a solid block of metal hydride. The fuel insert may alternatively be manufactured by injection molding, sintering, or any other suitable method of manufacturing a fuel insert. The fuel insert preferably includes guide grooves, preferably a liquid delivery mechanism (LDM) guide groove and/or an alignment groove. The LDM guide groove functions to allow easy insertion and alignment of the LDM with the insert. The alignment groove functions to align the fuel insert with other fuel inserts, the elastic enclosure and/or other components encapsulated within the elastic enclosure in the end product (e.g. exhaust nozzles, filters, etc.). The guide grooves are preferably located on the exterior of the fuel insert, but may alternately be located on the interior. However, the fuel insert may alternately include other grooves or not include any grooves at all. The fuel insert may additionally include any suitable alignment features. The reaction chamber preferably includes one fuel insert, but may additionally include any number of fuel inserts of any composition.
The reaction chamber may additionally include a liquid delivery mechanism (LDM) 220 that functions to deliver a liquid reagent to the reaction zone. The reaction zone is preferably the surface of the fuel insert, but may alternatively be on the interior of the fuel insert. The LDM is preferably a flexible tube, but may alternatively comprise a nozzle, multiple tubes of different lengths, multiple tubes of the same length, multiple nozzles of different varieties, a combination of the above, or any other suitable liquid delivery mechanism. The LDM is preferably the longer than the length of the fuel insert such that it covers the entirety of the fuel insert, but may alternately cover only a portion of the fuel insert, or be substantially shorter than the fuel insert. However, the LDM may be any suitable configuration to deliver liquid reagent to the reaction zone. The LDM is preferably substantially solid such that it does not leak, but may alternatively have holes or be porous along a section (e.g. the section proximal to the insert after assembly or the whole length). The LDM is preferably flexible, but may be substantially rigid. The LDM is preferably impervious to the liquid reagent, and preferably comprises ultra-high molecular weight polyethylene (UHMWPE), high-density polyethylene (HDPE), polypropylene, PTFE, PVDF, or any other suitable material. The LDM may additionally include a distribution mechanism, such as wicking materials leading from the lumen of the LDM to the exterior to facilitate liquid reagent distribution, pores along the fuel insert-contacting length, side channels, or any other suitable distribution mechanism. The reaction chamber preferably includes one LDM, but may alternatively include a plurality of LDMs of the same or of varying lengths.
The step of stretching the body of the elastic enclosure to define a working lumen S200 functions to achieve an elastic enclosure configuration that allows for easy fuel insert insertion. The working lumen 160 is preferably formed from the elastic enclosure body interior, wherein the elastic enclosure body is stretched to a diameter and length that readily accepts the desired portion of the fuel insert (e.g. stretched to achieve dimensions larger than the fuel insert, stretched to a larger diameter than the insert, stretched to a longer length than the insert length or width, etc). S200 may additionally include the step of halting and maintaining the working lumen configuration, wherein the stretching force is adjusted and/or maintained to retain the desired working lumen configuration.
In a first embodiment (“vacuum embodiment”) of S200, the working lumen is achieved by pulling suction on the exterior of the elastic enclosure, and preferably uses a vacuum tube 300 coupled to a vacuum generator (suction generator), wherein the vacuum tube includes an opening through which the elastic enclosure is received into the vacuum tube lumen. The vacuum tube is preferably substantially sealed except for the vacuum tube opening, and preferably has a substantially constant diameter throughout its length but may alternately have a variable diameter. As shown in
As shown in
As shown in
In a second embodiment of S200, the working lumen is created by utilizing positive pressure within the elastic enclosure body (“positive pressure embodiment”). In a first embodiment of the positive pressure embodiment (“enclosure-stretching apparatus lumen stretching” embodiment), as shown in
The step of orienting the fuel insert within the working lumen S300 functions to ensure that the elastic enclosure restitutes over the insert in a desired configuration (shown in
The step of restituting the elastic enclosure over the fuel insert S400 functions to create continuous contact between the elastic enclosure and the fuel insert, (shown in
As shown in
As shown in
As shown in
The method of manufacturing a reaction chamber may additionally include repeating any of the aforementioned steps, preferably at least S200, S300, and S400, for additional elastic enclosures, such that the fuel insert is encapsulated by two or more elastic enclosures.
As a person skilled in the art will recognize from the previous detailed description and from the figures and claims, modifications and changes can be made to the preferred embodiments of the invention without departing from the scope of this invention defined in the following claims.
Claims
1. A method for manufacturing a reaction chamber, the reaction chamber having a fuel insert and an elastic enclosure, the elastic enclosure having a body and an opening portion that defines an opening in the elastic enclosure, the method comprising the steps of:
- a) stretching the body of the elastic enclosure to define a working lumen;
- b) orienting the fuel insert within the working lumen; and
- c) restituting the elastic enclosure over the insert.
2. The method of claim 1, wherein step (a) further includes the steps of:
- placing the body of the elastic enclosure within a vacuum tube, wherein the opening of the elastic enclosure is disposed outside the vacuum tube;
- securing the elastic enclosure opening portion to the vacuum tube opening, thereby sealing the vacuum tube opening; and
- defining a working lumen in the elastic enclosure by pulling a suction within the vacuum tube to expand the elastic enclosure body.
3. The method of claim 2, wherein step (a) further includes the step of sealing the elastic enclosure to leave one opening.
4. The method of claim 3, wherein the elastic enclosure is a tube, and the end opposing the opening is sealed.
5. The method of claim 2, wherein step (c) includes the step of releasing the suction within the vacuum tube.
6. The method of claim 2, wherein the step of securing the elastic enclosure opening portion to the vacuum tube opening includes disposing the elastic enclosure opening portion in a fold over the vacuum tube opening, such that the body of the elastic enclosure is encapsulated within the vacuum tube lumen and the elastic enclosure opening portion is disposed outside the vacuum tube.
7. The method of claim 6, wherein disposing the elastic enclosure opening portion in a fold over the vacuum tube opening comprises the steps of:
- folding the elastic enclosure opening portion over a stretching apparatus;
- stretching the elastic enclosure opening portion radially to a diameter larger than the vacuum tube diameter;
- sliding the vacuum tube into the fold between the elastic enclosure opening portion and the elastic enclosure body; and
- transferring the folded elastic enclosure to the vacuum tube.
8. The method of claim 6, wherein the elastic enclosure opening portion has substantially the same diameter as the body.
9. The method of claim 6, wherein the elastic enclosure is stretched prior to disposing the elastic enclosure opening portion in a fold over the vacuum tube opening.
10. The method of claim 6, wherein the elastic enclosure opening portion is flared outward from the body.
11. The method of claim 10, wherein a portion of the flared opening has a diameter larger than the vacuum tube diameter.
12. The method of claim 10, wherein the method further includes the step of flaring the elastic enclosure opening portion, which includes the steps of:
- placing a portion of the elastic enclosure body within the vacuum tube lumen while leaving a second portion of the elastic enclosure outside the vacuum tube, wherein the second portion is proximal to the elastic enclosure opening portion;
- coupling the elastic enclosure opening to a pressure source; and
- pressurizing the elastic enclosure such that a section of the second portion is flared to a diameter larger than the vacuum tube diameter.
13. The method of claim 12, wherein the step of disposing the elastic enclosure opening portion in a fold over the vacuum tube opening includes the step of pushing the flared portion of the elastic enclosure over the exterior of the vacuum tube.
14. The method of claim 2, wherein step (a) further includes the step of lubricating the vacuum tube.
15. The method of claim 1, wherein step (b) further includes the steps of:
- positioning the fuel insert relative to the working lumen opening; and
- inserting a portion of the fuel insert into the working lumen.
16. The method of claim 15, wherein the step of positioning the fuel insert includes using a guide.
17. The method of claim 16, wherein the fuel insert includes multiple pieces, and the guide retains the relative positions of the multiple pieces.
18. The method of claim 15, wherein the fuel insert is fully inserted into the working lumen.
19. The method of claim 15, wherein the step of inserting a portion of the fuel insert into the working lumen includes the step of inverting the working lumen over the fuel insert.
20. The method of claim 1, wherein step (c) includes the step of maintaining the fuel insert position within the working lumen.
21. The method of claim 1, further comprising the step of inserting a liquid delivery mechanism between the fuel insert and the elastic enclosure.
22. The method of claim 21, wherein the step of inserting a liquid delivery mechanism occurs before the step of restituting the elastic enclosure over the fuel insert, wherein the step of inserting a liquid delivery mechanism includes the steps of:
- positioning the liquid delivery mechanism within the working lumen; and
- maintaining the liquid delivery mechanism position during restitution.
23. The method of claim 21, wherein the step of inserting a nozzle occurs after the step of restituting the elastic enclosure over the insert, wherein the step of inserting a liquid delivery mechanism includes the steps of:
- stretching a portion of the elastic enclosure away from the insert;
- positioning the liquid delivery mechanism between the insert and the elastic enclosure; and
- releasing the portion of the elastic enclosure.
24. The method of claim 1, further comprising the step of trimming the excess restituted elastic enclosure from the reaction chamber.
25. The method of claim 1, wherein steps (a), (b) and (c) are repeated for a second elastic enclosure, wherein the fuel insert is encapsulated in a first elastic enclosure.
26. A method for manufacturing a reaction chamber, the reaction chamber comprising a metal hydride insert and an elastic enclosure, the elastic enclosure including a body and an opening portion that defines an opening in the elastic enclosure, the method comprising:
- placing the body of the elastic enclosure within a vacuum tube, wherein the opening portion of the elastic enclosure is disposed outside the vacuum tube;
- securing the elastic enclosure opening portion to the vacuum tube opening, thereby sealing the vacuum tube opening;
- defining a working lumen in the elastic enclosure by reducing air pressure within the vacuum tube to expand the elastic enclosure body;
- maintaining constant vacuum tube pressure when the elastic enclosure is stretched to a desired working lumen size;
- orienting the metal hydride insert within the working lumen;
- maintaining the insert orientation; and
- allowing pressure increase within the vacuum tube to allow restitution of the elastic enclosure about the insert.
27. The method of claim 26, further comprising the step of inserting a liquid delivery mechanism between the insert and the elastic enclosure.
28. The method of claim 26, wherein the step of securing the elastic enclosure opening to the vacuum tube opening includes disposing the elastic enclosure opening in a fold over the vacuum tube opening edge, such that the body of the elastic enclosure is enclosed within the vacuum tube lumen and the elastic enclosure opening is disposed on the vacuum tube exterior.
29. The method of claim 28, wherein the step of disposing the elastic enclosure opening in a fold over the vacuum tube opening includes the steps of:
- folding the elastic enclosure opening portion over a stretching apparatus;
- stretching the elastic enclosure opening portion radially to a diameter larger than the vacuum tube opening diameter;
- sliding the vacuum tube into the fold between the elastic enclosure opening portion and the elastic enclosure body; and
- transferring the folded elastic enclosure to the vacuum tube.
30. The method of claim 28, wherein the elastic enclosure opening portion is flared outward from the body, and the step of disposing the elastic enclosure opening in a fold over the vacuum tube opening includes the step of stretching the flared opening over the vacuum tube opening.
31. The method of claim 30, further comprising the step of flaring the opening, which includes the steps of: wherein the step of disposing the elastic enclosure opening in a fold over the vacuum tube opening includes the step of pushing the flared portion of the elastic enclosure over the exterior of the vacuum tube.
- placing a portion of the elastic enclosure body within the vacuum tube lumen while leaving a second portion of the elastic enclosure outside the vacuum tube, wherein the second portion includes the elastic enclosure opening portion;
- coupling the elastic enclosure opening to a pressure source; and
- pressurizing the elastic enclosure such that the second portion of the elastic enclosure is flared to a diameter larger than the vacuum tube diameter;
Type: Application
Filed: Jul 26, 2011
Publication Date: Jan 26, 2012
Inventors: KEI EDGARDO YAMAMOTO (SAN FRANCISCO, CA), COURTNEY ALINE HELLAND (SAN FRANCISCO, CA), MATTHIEU JONEMANN (SAN FRANCISCO, CA), ANDREW PETERSON (SAN FRANCISCO, CA), DANIEL BRAITHWAITE (SAN FRANCISCO, CA)
Application Number: 13/191,360
International Classification: B21D 51/16 (20060101);