In the accompanying drawings forming a part of this specification and in which reference numerals shown in the drawings designate like or corresponding parts throughout the same:
The invention is generally indicated by numeral 10 in
Each reactor 12 is provided with its own heating element 14. Each reactor 12 has its own intake line 16 for delivery of the process gas into the reactor and its own exhaust line 18 for exhausting the process gas. The exhaust lines 18 for the reactors 12 lead to a common effluent scrubber not shown. Insulation 20 is held in place around the reactors 12 and heating elements 14 by a furnace jacket 22.
In operation, the process of coating substrates is carried out in essentially the same manner as when using a single large reactor. The difference is the use of multiple smaller reactors that eliminate the risk and difficulty normally associated with scaling up a newly developed FBCVD process.
The invention has two primary advantages over scaling a process for use in a larger reactor. One is that development costs are not required if multiple small or intermediate reactors (the same size used to develop the FBCVD process) are used in a large furnace. A second advantage is that the use of multiple reactors allows stopping the coating process in one reactor without losing the entire batch of substrates. The coating in one reactor can be stopped while the others continue without losing the entire furnace run. When only a single large reactor is used, as in the current known art, the entire furnace run is lost if a problem causes the process to be stopped. If the substrates are valuable (e.g., nuclear fuel kernels), significant money can be saved with the ability to continue the process in the remaining reactors according to the inventive concept.
The invention is applicable to any FBCVD process. It is not limited to the number of reactors contained within a furnace. While the description illustrates an example using three reactors, it should be understood that two, three, or more reactors may be used. The invention is not limited by the materials of which the furnace system is constructed or the type of furnace control equipment. Further, the invention is not limited to the design of the furnace or reactor since this would be specific to a process. For example, a particular process may require a thermal gradient in the furnace which would be controlled by the type and amount of insulation and the design of the heating element(s).
While specific embodiments and/or details of the invention have been shown and described above to illustrate the application of the principles of the invention, it is understood that this invention may be embodied as more fully described in the claims, or as otherwise known by those skilled in the art (including any and all equivalents), without departing from such principles.
This invention was made, in part, with government support under Contract No. DE-AC07-05ID14517 awarded by the Department of Energy. The United States government has certain rights in this invention.