# Patent

## Title
Fluid recirculation system for use in vapor phase particle production system

## Abstract

A method of and system for recirculating a fluid in a particle production system. A reactor produces a reactive particle-gas mixture. A quench chamber mixes a conditioning fluid with the reactive particle-gas mixture, producing a cooled particle-gas mixture that comprises a plurality of precursor material particles and an output fluid. A filter element filters the output fluid, producing a filtered output. A temperature control module controls the temperature of the filtered output, producing a temperature-controlled, filtered output. A content ratio control module modulates the content of the temperature-controlled, filtered output, thereby producing a content-controlled, temperature-controlled, filtered output. A channeling element supplies the content-controlled, temperature-controlled, filtered output to the quench chamber, wherein the content-controlled, filtered output is provided to the quench chamber as the conditioning fluid to be used in cooling the reactive particle-gas mixture.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 13/907,667, filed May 31, 2013, which is a divisional of U.S. patent application Ser. No. 12/151,765, filed May 8, 2008, now U.S. Pat. No. 8,574,408, issued Nov. 5, 2013, which claims priority benefit of U.S. Provisional Application Ser. No. 60/928,946, filed May 11, 2007, entitled “MATERIAL PRODUCTION SYSTEM AND METHOD,” all of which are hereby incorporated by reference in their entireties as if set forth herein. The entire contents of U.S. patent application Ser. No. 11/110,341, filed on Apr. 19, 2005, entitled, “HIGH THROUGHPUT DISCOVERY OF MATERIALS THROUGH VAPOR PHASE SYNTHESIS” are incorporated by reference herein.


FIELD OF THE INVENTION
The present invention relates generally to the field of particle production. More specifically, the present invention relates to systems and methods for recirculating fluid used within a vapor phase particle production system.
BACKGROUND OF THE INVENTION
Many vapor phase particle production systems produce mixtures of particles and fluid. Typically, these mixtures are high in temperature and thus reactive. In some systems, these mixtures are quenched via introduction of a conditioning fluid. The conditioning fluid acts to cool the mixture and promote particle formation, and often acts as a carrier for the particles. Typically, particles are sampled or collected from the mixture following introduction of the conditioning fluid. Then, the conditioning fluid is vented to the ambient, or otherwise disposed. This disposal occurs because typical particle production systems require high purity gases as conditioning fluids. In many cases, the purity must be on the order of 99.9999% purity. The unit cost of particles produced using these methods is inflated by the need to use fresh fluid for each production run.
What is needed in the art is a way to reduce the costs associated with a vapor phase particle production system, while at the same time maintaining a high purity level for the system.
SUMMARY OF THE INVENTION
In one aspect of the present invention, a particle production system comprises a particle production core and a fluid recirculation system fluidly coupled to the particle production core. The production core is configured to produce a reactive particle-gas mixture from a precursor material and a working gas, and to quench the reactive particle-gas mixture using a conditioning fluid, thereby producing a cooled particle-gas mixture. The cooled particle-gas mixture comprises a plurality of precursor material particles and an output fluid. The output fluid includes the conditioning fluid. The fluid recirculation system is configured to receive the cooled particle-gas mixture from the particle production core, and to remove the plurality of precursor material particles from the cooled particle-gas mixture, thereby producing a filtered output that includes the output fluid. The fluid recirculation system is also configured to modulate a content ratio of the filtered output, thereby producing a content-controlled, filtered output, wherein the filtered output comprises a distinct primary fluid and a distinct secondary fluid, and the content ratio is the ratio of the primary fluid to the secondary fluid. The fluid recirculation system is further configured to channel the content-controlled, filtered output to the particle production core, wherein the content-controlled, filtered output is provided to the particle production core as the conditioning fluid to be used in quenching the reactive particle-gas mixture.
In a preferred embodiment, the particle production core comprises a particle production reactor and a quench chamber fluidly coupled to the particle production reactor. The particle production reactor is configured to receive the precursor material and the working gas, to energize the working gas to form a plasma, and to apply the plasma to the precursor material, thereby producing the reactive particle-gas mixture. The quench chamber is configured to receive the reactive particle-gas mixture from the particle production reactor, to receive the content-controlled, filtered output from the recirculation system as the conditioning fluid, and to mix the received conditioning fluid with the reactive particle-gas mixture, thereby producing the cooled particle-gas mixture.
In some embodiments, the fluid recirculation system is further configured to control the temperature of the filtered output prior to modulation of the content ratio.
Furthermore, in some embodiments, the fluid recirculation system is further configured to sense the ratio between the primary fluid and the secondary fluid, and to modulate the content ratio of the filtered output by adjusting the amount of either the primary fluid or the secondary fluid in the content-controlled, filtered output based on the sensed ratio.
In another aspect of the present invention, a particle production system comprises a particle production reactor and a quench chamber having a fluid inlet, a reactive mixture inlet fluidly coupled to the particle production reactor, and a cooled mixture outlet. The particle production system also comprises a filter element fluidly coupled to the cooled mixture outlet, a temperature control module fluidly coupled to the filter element, a content ratio control module fluidly coupled to the temperature control module, and a channeling element fluidly coupling the content ratio control module to the fluid inlet of the quench chamber.
The particle production reactor is configured to produce a reactive particle-gas mixture from a precursor material and a working gas. The quench chamber is configured to receive a conditioning fluid at the fluid inlet, to receive the reactive particle-gas mixture mix fluid from the particle production reactor at the reactive mixture inlet, and to mix the conditioning fluid with the reactive particle-gas mixture to produce a cooled particle-gas mixture. The cooled particle-gas mixture comprises a plurality of precursor material particles and an output fluid, the output fluid including the conditioning fluid. The filter element is configured to receive and filter the output fluid from the quench chamber to produce a filtered output. The temperature control module is configured to control the temperature of the filtered output to produce a temperature-controlled, filtered output. The content ratio control module is configured to modulate a content ratio of the temperature-controlled, filtered output, thereby producing a content-controlled, temperature-controlled, filtered output, wherein the temperature-controlled, filtered output comprises a distinct primary fluid and a distinct secondary fluid, and the content ratio is the ratio of the primary fluid to the secondary fluid. Finally, the channeling element is configured to supply the content-controlled, temperature-controlled, filtered output to the fluid inlet of the quench chamber, wherein the content-controlled, filtered output is provided to the quench chamber as the conditioning fluid to be used in quenching the reactive particle-gas mixture.
In a preferred embodiment, the particle production reactor is configured to energize the working gas to form a plasma, and to apply the plasma to the precursor material, thereby producing the reactive particle-gas mixture.
In some embodiments, the system also comprises a suction generator configured to generate a suction force at the cooled mixture outlet of the quench chamber to draw the output fluid from the quench chamber.
In some embodiments, the filter element is configured to remove the plurality of precursor material particles from the output fluid to produce the filtered output. Furthermore, the filter element preferably comprises a high efficiency particulate air (HEPA) filter.
In some embodiments, a pressure relief module is fluidly coupled between the filter element and the temperature control module. This pressure relief module is configured to reduce the pressure of the filtered output if the pressure exceeds a predetermined threshold.
In some embodiments, the temperature control module comprises a heat exchanger. It is also contemplated that other means for adjusting fluid temperature can be employed.
In a preferred embodiment, the content ratio control module comprises a sensor and a micro-controller communicatively connected to the sensor. The sensor is configured to sense the content ratio of the temperature-controlled, filtered output, and to produce a signal representing the sensed content ratio. The micro-controller is configured to receive the signal from the sensor and modulate the content ratio of the content-controlled, temperature-controlled, filtered output that is to be supplied to the fluid inlet of the quench chamber. This modulation is based on the received signal.
In some embodiments, the content ratio control module can further comprise a buffer reservoir fluidly coupled to the temperature control module and to the sensor. The buffer reservoir is configured to receive the temperature-controlled, filtered output from the temperature control module and to temporarily store the temperature-controlled, filtered output before the content ratio of the temperature-controlled, filtered output is modulated. The content ratio control module can also comprise a fluid relief valve fluidly coupled between the buffer reservoir and the ambient atmosphere. This fluid relief valve is configured to vent the secondary fluid from the buffer reservoir to the ambient atmosphere.
Furthermore, the content ratio control module can comprise a secondary fluid supply reservoir that stores a supply of the secondary fluid and is communicatively connected to the micro-controller. This secondary fluid supply reservoir is configured to selectively add a portion of the secondary fluid from the secondary fluid supply reservoir into the temperature-controlled, filtered output in response to a signal from the micro-controller, thereby producing the content-controlled, temperature-controlled, filtered output.
The content ratio control module can additionally or alternatively comprise a primary fluid supply reservoir that stores a supply of the primary fluid and is communicatively connected to the micro-controller. The primary fluid supply reservoir is configured to selectively add a portion of the primary fluid from the primary fluid supply reservoir into the temperature-controlled, filtered output in response to a signal from the micro-controller, thereby producing the content-controlled, temperature-controlled, filtered output.
In addition to these systems, the present invention also includes methods of recirculating fluid within these systems, involving the operations discussed both above and below.



BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic illustration of one embodiment of a fluid recirculation system integrated into a particle production system in accordance with the principles of the present invention.
FIG. 2 is a schematic illustration of one embodiment of the particle production system of FIG. 1 with a more detailed embodiment of the content ratio control module in accordance with the principles of the present invention.
FIG. 3A is a schematic illustration of one embodiment of a content ratio control module in accordance with the principles of the present invention.
FIG. 3B is a schematic illustration of another embodiment of a content ratio control module in accordance with the principles of the present invention.
FIG. 4 is a flow chart illustrating one embodiment of a method of recirculating a fluid in a particle production system in accordance with the principles of the present invention.



DETAILED DESCRIPTION OF THE INVENTION
The description below concerns several embodiments of the invention. The discussion references the illustrated preferred embodiment. However, the scope of the present invention is not limited to either the illustrated embodiment, nor is it limited to those discussed. To the contrary, the scope should be interpreted as broadly as possible based on the language of the Claims section of this document.
In the following description, numerous details and alternatives are set forth for purpose of explanation. However, one of ordinary skill in the art will realize that the invention can be practiced without the use of these specific details. In other instances, well-known structures and devices are shown in block diagram form in order not to obscure the description of the invention with unnecessary detail.
This disclosure refers to both particles and powders. These two terms are equivalent, except for the caveat that a singular “powder” refers to a collection of particles. The present invention may apply to a wide variety of powders and particles.
The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings. To facilitate this description, like reference numerals designate like elements.
FIG. 1 illustrates one embodiment of a fluid recirculation system integrated into a particle production system 100 in accordance with the principles of the present invention. The particle production system 100 includes a particle production core 120, which takes various material inputs, including both working and conditioning fluids as well as particle precursors, and produces a particle-gas mixture. The two main components of the particle production core 120 are a particle production reactor 122, configured to produce a reactive particle-gas mixture from a precursor material and a working gas, and a quench chamber 124, configured to quench the reactive particle-gas mixture using a conditioning fluid.
In general, vapor phase particle production means are preferred for producing the particle-gas mixture in the particle production core 120. Most preferably, the embodiments of the present invention use particle production systems similar to those disclosed in U.S. patent application Ser. No. 11/110,341, filed on Apr. 19, 2005 and entitled, “HIGH THROUGHPUT DISCOVERY OF MATERIALS THROUGH VAPOR PHASE SYNTHESIS”, which is currently published as U.S. Publication No. 2005-0233380-A. In such a particle production system, working gas is supplied from a gas source to a plasma reactor. Within the plasma reactor, energy is delivered to the working gas, thereby creating a plasma. A variety of different means can be employed to deliver this energy, including, but not limited to, DC coupling, capacitive coupling, inductive coupling, and resonant coupling. One or more material dispensing devices introduce at least one material, preferably in powder form, into the plasma reactor. The combination within the plasma reactor of the plasma and the material(s) introduced by the material dispensing device(s) forms a highly reactive and energetic mixture, wherein the powder can be vaporized. This mixture of vaporized powder moves through the plasma reactor in the flow direction of the working gas. As it moves, the mixture cools and particles are formed therein. The still-energetic output mixture, comprising hot gas and energetic particles, is emitted from the plasma reactor. Following emission from the plasma reactor, the output mixture can cool further. This output mixture may comprise hot gas and particles of relatively homogeneous size distribution. Each particle can comprise a combination of the materials introduced by the material dispensing devices. It is contemplated that portions of these or other particle production means, including non-vapor phase particle production means, are within the scope of the present invention as well and can be employed as part of the particle production core 120.
In a preferred embodiment, the reactor 122 is fluidly coupled to a working gas supply 110 via a working gas inlet 111, thereby allowing the reactor 122 to receive a working gas from the working gas supply 110. Examples of working gas include, but are not limited to, argon and hydrogen. The reactor 122 can also be fluidly coupled to a precursor material supply 115 via a precursor material inlet 116, thereby allowing the reactor 122 to receive precursor material, such as precursor material powder, from the precursor material supply 115. The reactor 122 combines the working gas and the precursor material to produce a reactive particle-gas mixture. In a preferred embodiment, as discussed above, energy is delivered to the working gas within the reactor 122, thereby creating a plasma. The plasma is then applied to the precursor material. The application of the plasma to the precursor material(s) forms a highly reactive and energetic mixture, wherein the powder can be vaporized. This mixture of vaporized powder moves through the reactor 122 in the flow direction of the working gas. This reactive particle-gas mixture flows into the quench chamber 124, preferably via reactive mixture port 123, which fluidly couples the reactor 122 to the quench chamber 124.
In addition to being configured to receive the reactive mixture from the reactor 122, the quench chamber 124 is also configured to receive recirculated conditioning fluid. One example of a conditioning fluid is argon. However, it is contemplated that other fluids may be used in addition to or as alternatives to argon. In a preferred embodiment, the quench chamber 124 is housed within a conditioning fluid input manifold 125, which itself receives recirculated conditioning fluid through a conditioning fluid inlet 119. The conditioning fluid is supplied to the conditioning fluid input manifold 125 via a recirculation system discussed in detail below. The manifold 125 is fluidly coupled to the quench chamber 124, preferably via one or more conditioning fluid ports 121, thereby providing the recirculated conditioning fluid to the quench chamber 124.
The quench chamber 124 mixes the conditioning fluid with the reactive particle-gas mixture from the reactor 122, thereby quenching the reactive particle-gas mixture. This quenching rapidly cools the reactive mixture to form a cooled particle-gas mixture. The cooled mixture is preferably drawn into a conduit system 126 that is fluidly coupled to the quench chamber. In a preferred embodiment, the cooled mixture is drawn into the conduit system 126 by suction supplied by a suction generator 128, such as a pump, drawing the cooled mixture towards the suction generator 128. A powder product can be sampled or collected from the cooled mixture between the quench chamber 124 and the suction generator 128. Such sampling or collection can be achieved in a variety of ways.
Outside of the quench chamber 124 and the particle production core 120, the rest of the particle production system 100 comprises a fluid recirculation system, which includes a plurality of elements fluidly coupled via a conduit system 180. The fluid recirculation system is configured to receive the cooled mixture from the particle production core, filter the cooled mixture to produce a filtered output, modulate the content ratio of the filtered output to produce a content-controlled, filtered output, and channel the content-controlled, filtered output to the particle production core 120 to be used as the recirculated conditioning fluid in quenching the reactive mixture. The means for performing these operations, as well as other functions, will be discussed in further detail below.
In a preferred embodiment, the fluid recirculation system comprises a filter element 130 fluidly coupled to the suction generator, a pressure relief module 140 fluidly coupled to the filter element 130, a temperature control module 150 fluidly coupled to the pressure relief module 140, and a content ratio control module 160 fluidly coupled to the temperature control module 150 and to the particle production core 120, thereby creating a recirculation path from the output of the particle production core 120 to the input of the particle production core 120. It is contemplated that the scope of the present invention can include the rearrangement or removal of some of these components. For example, pressure relief module 140 may be disposed between temperature control module 150 and content control module 160, rather than between filter element 130 and temperature control module 150. In an alternative example, pressure relief module 140 can be completely removed from the fluid recirculation path.
The suction generator 128 preferably moves the cooled particle-gas mixture out of the particle production core through the conduit system 126 and into the filter element 130. The filter element 130 is configured to remove remaining particles, such as precursor material particles, from the cooled mixture, thereby producing a filtered output. Preferably, the filter element 130 is a high efficiency particulate air (HEPA) filter. In some embodiments, the filter element 130 does not completely remove all of the particles from the cooled mixture.
Following passage through the filter element 130, the cooled mixture becomes a filtered output, which is channeled into the conduit system 180. The conduit system 180 fluidly couples the filter element 130 to the pressure relief module 140 such that the pressure relief module 140 can receive the filtered output from the filter element 130. The pressure relief module 140 is configured to reduce the pressure of the fluid of the filtered output. This pressure reduction can be conditioned upon the pressure of the fluid exceeding a predetermined threshold. Furthermore, this pressure reduction can be achieved in a variety of ways, including, but not limited to, venting to ambient atmosphere. As noted above, in some embodiments, no pressure relief module 140 is included at all.
Following passage through the pressure relief module 140, the filtered output passes into the temperature control module 150. The temperature control module 150 is configured to regulate the temperature of the output, thereby forming a temperature-controlled, filtered output. In a preferred embodiment, the temperature control module 150 comprises a heat exchanger. Additionally, in some embodiments, no temperature control module 150 is included at all.
The temperature-controlled, filtered output reenters a portion of the conduit system 180 that fluidly couples the temperature control module 150 to the content ratio control module 160. The content ratio control module 160 is configured to receive and modulate the content ratio of the temperature-controlled, filtered output, thereby producing a content-controlled, temperature-controlled, filtered output. In a preferred embodiment, the filtered output that is received by the content control module 160 comprises a distinct primary fluid and a distinct secondary fluid. The content control module 160 controls the ratio of the primary fluid to the secondary fluid, making adjustments when necessary, thereby producing the content-controlled output.
This content-controlled output, still comprising conditioning fluid from the quench chamber, is then channeled through another portion of the conduit system 180 to the conditioning fluid inlet 119 of the particle production core 120 for use in quenching. Thus, the output of the quench chamber 124, which includes the conditioning fluid, has been recirculated back into the quench chamber 124. This recirculation includes the filtering and the content control (and in some cases, the pressure relief and the temperature control) of the fluid to ensure sufficient preparation for the fluid's reuse in quenching the reactive mixture in the particle production core 120.
FIG. 2 illustrates one embodiment of a particle production system 200, similar to the system 100 of FIG. 1, with a more detailed embodiment of the content ratio control module 160 in accordance with the principles of the present invention. The content ratio control module 160 can include a plurality of components. Some components are fluidly coupled with the conduit system 180. For example, a buffer reservoir 260 is preferably coupled to the conduit system 180 and in fluid communication with the temperature control module 150.
The content ratio control module 140 of some embodiments receives the temperature-controlled, filtered output from the temperature control module 150 in the buffer reservoir 260. The buffer reservoir 260 acts as a fluid buffer, holding the temperature-controlled, filtered output for a period of time before releasing it. During the time while the temperature-controlled, filtered output is within the buffer reservoir 260, the fluid within the output begins to separate based on density because of gravity. In the embodiments where the output comprises a primary fluid and a secondary fluid, the secondary fluid is preferably a less dense fluid. Thus, in these embodiments, the primary fluid concentrates in a lower portion of the buffer reservoir 260, while the secondary fluid concentrates in an upper portion of the buffer reservoir 260.
In a preferred embodiment, the content control module also comprises a content ratio sensor 262 coupled into the conduit system and in fluid communication with the buffer reservoir 260. The content ratio sensor 262 is configured to receive a portion of the fluid mixture, determine the content ratio of the mixture (e.g., the ratio fo primary fluid to secondary fluid), and provide one or more signals representing the content ratio.
The buffer reservoir 260 can be configured to permit venting of the secondary fluid from the system 200. In one embodiment of such a configuration, the buffer reservoir 260 is fluidly coupled to a secondary fluid relief element 264. The secondary fluid relief element 264 is in fluid communication with the ambient environment of the particle production system 200 and is configured to selectively permit fluid communication between the buffer reservoir 260 and the ambient atmosphere.
A secondary fluid supply 266 can be fluidly coupled to the conduit system 180 to permit selective fluid communication with the conduit system 180, and thereby with the content ratio sensor 262. The secondary fluid supply 266 is configured to store and selectively introduce an amount of secondary fluid into the fluid mixture to increase the amount of secondary fluid in the mixture relative to the amount of primary fluid, thereby adjusting the content ratio.
The content ratio control module 160 preferably includes a micro-controller 268. The micro-controller 268 is communicatively connected to the content ratio sensor 262, thereby enabling the micro-controller 268 to receive signals from the content ratio sensor 262 that represent the content ratio of the fluid within the conduit system 180 that is in the vicinity of the content ratio sensor 262. The micro-controller 268 is also communicatively connected to the secondary fluid supply 266 and the secondary fluid relief element 264, thereby enabling the micro-controller 268 to select whether the secondary fluid supply 266 is in fluid communication with the conduit system 180 to add secondary fluid and select whether the relief element 264 provides fluid communication between the buffer reservoir 260 and the ambient environment to vent the secondary fluid. The micro-controller 268 can make any or all of these selections based on the content ratio as represented by the signal provided by the content ratio sensor 262.
During the time while the temperature-controlled, filtered output is within the buffer reservoir 260, the secondary fluid relief module 264 can operate to make an initial adjustment to the level of secondary fluid within the buffer reservoir 260. The relief module 264 is preferably coupled to the upper portion of the buffer reservoir 260 to take advantage of the gravity-based separation of the secondary and primary fluids. The micro-controller 268 controls relief of the secondary fluid by the relief module 264. Preferably, the secondary fluid relief module 264 operates by relieving fluid at a continuous rate. The rate can be variable and is preferably determined by the micro-controller 268.
Following the initial adjustment of the secondary fluid level, the adjusted output moves out of the buffer reservoir 260 and into a portion of the conduit system 180 that fluidly couples the buffer reservoir 260 to the content ratio sensor 262. The content ratio sensor 262 detects the ratio of the primary fluid to the secondary fluid within the adjusted output, then sends a signal representing the ratio to the micro-controller 268.
Meanwhile, the adjusted output moves through another portion of the conduit system 180 that fluidly couples the sensor 262 to the outlet of the secondary fluid supply 266. The micro-controller 268 controls the secondary fluid supply 266 to introduce secondary fluid into the adjusted output. The micro-controller 268 uses the signal from the content ratio sensor 262 in determining the rate at which secondary fluid is introduced into the output. The result of these adjustments is the production of a content-controlled, temperature-controlled, filtered output.
This output is channeled through a portion of the conduit system 180 that fluidly couples the outlet of the secondary fluid supply 266 to the conditioning fluid inlet 119 of the particle production core 120. Thus, the content-controlled, temperature-controlled, filtered output is supplied to the particle production core 120 as conditioning fluid.
Because the working gas from the working gas supply 110 becomes part of the output of the particle production core 120, the recirculated conditioning fluid comprises the working gas. In some embodiments, the conditioning fluid is initially supplied from the working gas supply 110 in a charging step, where no precursor material is introduced into the reactor 122. The fluid recirculation system works during the charging step to modulate the characteristics of the conditioning fluid until desired characteristics are reached, at which point, the precursor material is introduced into the reactor 122.
FIG. 3A is a schematic illustration of one embodiment of a content ratio control module 300, similar to content ratio control module 160 shown in FIG. 2, in accordance with the principles of the present invention. A portion of the content ratio control module 300 is disposed along the conduit system 180. The conduit system 180 provides fluid communication between a buffer reservoir 260, a content ratio sensor 262, and a secondary fluid supply valve 366.
The secondary fluid supply valve 366 is fluidly coupled to a secondary fluid reservoir 367. The secondary fluid supply reservoir 367 contains a secondary fluid G2. The supply valve 366 enables selective fluid communication between the secondary fluid reservoir 367 and the conduit system 180, thereby allowing for the introduction of additional secondary fluid G2 into the conduit system 180 when appropriate.
Similarly, a primary fluid supply valve 376 is fluidly coupled between the buffer reservoir 260 and a primary fluid reservoir 377, which contains a primary fluid G1, thereby enabling selective fluid communication between the primary fluid reservoir 377 and the buffer reservoir 260 and allowing for the introduction of additional primary fluid G1 into the conduit system 180 when appropriate.
Additionally, the buffer reservoir 260 can be fluidly coupled to a secondary fluid relief valve 364, which is fluidly coupled with the ambient atmosphere, thereby enabling selective fluid communication between the buffer reservoir 260 and the ambient atmosphere. In an exemplary embodiment, the buffer reservoir 260 contains both primary fluid G1 and secondary fluid G2.
The content ratio control module 300 further includes micro-controller 268. The micro-controller 268 is communicatively connected to the content ratio sensor 262, thereby enabling the micro-controller 268 to receive signals from the content ratio sensor 262 that represent the content ratio of the fluid within the conduit system 180 that is in the vicinity of the content ratio sensor 262. The micro-controller 268 is also communicatively connected to the secondary fluid supply valve 366, the secondary fluid relief valve 364, and the primary fluid supply valve 376, thereby enabling the micro-controller 268 to select whether the secondary fluid supply reservoir 367 is in fluid communication with the conduit system 180 to add secondary fluid, to select whether the secondary fluid relief valve 364 provides fluid communication between the buffer reservoir 260 and the ambient environment to vent the secondary fluid, and to select whether the primary fluid supply reservoir 377 is in fluid communication with the conduit system 180 to add primary fluid. The micro-controller 268 can make any or all of these selections based on the content ratio as represented by the signal provided by the content ratio sensor 262.
In operation, the content ratio control module 300 receives the temperature-controlled, filtered output in the buffer reservoir 260. The buffer reservoir 260 acts as a fluid buffer, holding the temperature-controlled, filtered output for a period of time before releasing it.
During the time while the temperature-controlled, filtered output is within the buffer reservoir 260, the fluid within the output begins to separate based on density because of gravity. In the embodiments where the output comprises a primary fluid G1 and a secondary fluid G2, the secondary fluid G2 is preferably a less dense fluid. Thus, in these embodiments, the primary fluid G1 concentrates in a lower portion of the buffer reservoir 260, while the secondary fluid G2 concentrates in an upper portion of the buffer reservoir 260.
Also, during the time while the temperature-controlled, filtered output is within the buffer reservoir 260, the secondary fluid relief valve 364 can operate to make an initial adjustment to the level of secondary fluid G2 within the buffer reservoir 260. The relief valve 364 is preferably coupled to the upper portion of the buffer reservoir 260 to take advantage of the gravity-based separation of the secondary fluid G2 and primary fluid G1. The micro-controller 268 controls relief of the secondary fluid G2 by the relief valve 364. Preferably, the secondary fluid relief valve 364 operates by relieving secondary fluid G2 at a continuous rate. The rate can be variable and is preferably determined by the controller 268.
Additionally, during the time while the temperature-controlled, filtered output is within the buffer reservoir 260, the primary fluid supply valve 376 and reservoir 377 can operate to make an initial adjustment to the level of primary fluid G1 within the buffer reservoir 260. Although not shown, the primary fluid supply valve 376 can be coupled to the lower portion of the buffer reservoir to take advantage of the gravity-based separation of the secondary fluid G2 and primary fluid G1. The micro-controller 268 controls supply of the primary fluid G1 by the valve 376. Preferably, the primary fluid supply valve 376 operates by supplying primary fluid G1 at a continuous rate. The rate can be variable and is preferably determined by the micro-controller 268.
Following the initial adjustment of the secondary fluid level, the adjusted output moves out of the buffer reservoir 260 and into a portion of the conduit system 180 that fluidly couples the buffer reservoir 260 to the content ratio sensor 262. The content ratio sensor 262 detects the ratio of the primary fluid G1 to the secondary fluid G2 within the adjusted output and sends a signal representing the ratio to the micro-controller 268.
Meanwhile, the adjusted output moves through another portion of the conduit system 180 that fluidly couples the sensor 262 to the secondary fluid supply valve 367. The micro-controller 268 controls the secondary fluid supply valve 3672 to selectively introduce secondary fluid G2 into the adjusted output from the secondary fluid reservoir 367. The micro-controller uses the signal from the content ratio sensor 262 in determining the rate at which secondary fluid G2 is introduced into the output. The result of these adjustments is the production of a content-controlled, temperature-controlled, filtered output.
This output is channeled through a portion of the conduit system 180 that fluidly couples the content ratio control module 300 to the conditioning fluid inlet of the particle production core 120. Thus, the content-controlled, temperature-controlled, filtered output is supplied to the particle production core 120 as conditioning fluid.
FIG. 3B is a schematic illustration of another embodiment of a content ratio control module 300′ in accordance with the principles of the present invention. Content ratio control module 300′ is the same as content ratio control module 300, except that module 300′ does not include primary fluid supply valve 376 or primary fluid supply reservoir 377. In an alternative embodiment, primary fluid supply valve 376 and primary fluid supply reservoir 377 can be present while secondary fluid supply valve 366 or secondary fluid supply reservoir 367 are excluded. It is contemplated that several other different configurations are also well within the scope of the present invention.
FIG. 4 is a flow chart illustrating one embodiment of a method of recirculating a fluid in a particle production system in accordance with the principles of the present invention.
At step 402, the particle production core performs two main functions. First, it produces a reactive particle-gas mixture using a working gas and a precursor material. Preferably, this operation is performed via a particle production reactor as discussed above. Second, the particle production core quenches the reactive particle-gas mixture using recirculated conditioning fluid, resulting in the production of a cooled particle-gas mixture, which comprises a plurality of precursor material particles. Preferably, this operation is performed via a quenching chamber as discussed above.
The cooled particle-gas mixture then flows out of the particle production core and into the fluid recirculation system for preparation before being re-introduced back into the particle production core for use in quenching.
At step 404, the cooled particle-gas mixture flows into a filter, where the filter removes the precursor material particles from the cooled particle-gas mixture, thereby producing a filtered output. It is contemplated that, in some embodiments, the filter can be configured to remove all of the precursor material particles in the cooled particle-gas mixture, leaving no precursor material particles in the filtered output, while in other embodiments, the filter can be configured to remove less than all of the precursor material particles in the cooled particle-gas mixture, leaving a certain amount of the precursor material particles remaining in the filtered output.
At this point, the filtered output flows to the content ratio control module. However, it is contemplated that the filtered output can optionally be subjected to additional preparation before reaching the content ratio control module. If this additional preparation is desired, then at step 405, the filtered output can undergo temperature control and/or pressure relief, as discussed above with respect to the temperature module and the pressure relief module. For example, a portion of the filtered output can be vented to ambient, thereby reducing the pressure of the filtered output. The filtered output can then flow through a heat exchanger, thereby reducing its temperature.
At step 406, the filtered (and possibly temperature-controlled and pressure-relieved) output reaches the content ratio control module, where its content ratio is modulated. In a preferred embodiment, the filtered output comprises a distinct primary fluid and a distinct secondary fluid, and the content ratio is the ratio of the primary fluid to the secondary fluid. As discussed above, this modulation of the content ratio can involve one or more operations, including, but not limited to, a decrease in the amount of a certain fluid or the increase in the amount of a certain fluid. These operations are preferably performed with the use of one or more components, such as the micro-controller, sensor, reservoirs, and valves discussed above. The result of this content ratio modulation is the production of a content-controlled, filtered output that is now acceptable for reuse as conditioning fluid in quenching the reactive particle-gas mixture back in the particle production core.
At step 408, a channeling element recirculates the content-controlled, filtered output into the particle production core for use as conditioning fluid in the quenching of the reactive mixture back at step 402. This process 400 can be repeated several times, wherein the same conditioning fluid is recirculated and reused over and over again.
Embodiments of the present invention permit the recirculation and reuse of conditioning fluids within a particle production system. Furthermore, these embodiments permit the adjustment of a content ratio of the conditioning fluids, which may otherwise change undesirably with system use. Particle production systems incorporating embodiments of the present invention do not need a constant supply of fresh conditioning fluid. When fresh fluid is supplied, the system uses it for multiple production runs. Since the cost of fresh conditioning fluid is spread over more than one production run, the unit cost of the particles produced using the present invention is less than with conventional means.
Additionally, some embodiments described herein permit recirculation using filters with a specified tolerance so as not to filter out every particle from the output. These embodiments allow for use of less expensive filters on dedicated production lines where cross-contamination is not an issue.
The present invention has been described in terms of specific embodiments incorporating details to facilitate the understanding of the principles of construction and operation of the invention. As such, references herein to specific embodiments and details thereof are not intended to limit the scope of the claims appended hereto. It will be apparent to those skilled in the art that modifications can be made to the embodiments chosen for illustration without departing from the spirit and scope of the invention.

## Claims

1. A method comprising:
plasma vaporizing a precursor material using a first gas, thereby producing a vaporized particle-gas mixture;
quenching the vaporized particle-gas mixture using a conditioning fluid comprising a second gas, thereby producing a cooled particle-gas mixture comprising a plurality of particles comprising the precursor material;
removing the plurality of particles from the cooled particle-gas mixture, thereby producing a filtered output comprising the first gas and the second gas;
adjusting an amount of the filtered output, thereby producing a content-controlled, filtered output;
supplying the content-controlled, filtered output as the conditioning fluid for quenching the vaporized particle-gas mixture.

2. The method of claim 1, further comprising reducing pressure of the filtered output by venting a portion of the filtered output if the pressure exceeds a predetermined threshold.

3. The method of claim 1, wherein adjusting the amount of the filtered output comprises venting a portion of the filtered output.

4. The method of claim 1, wherein the filtered output has a temperature, and the method further comprises controlling the temperature of the filtered output.

5. The method of claim 1, wherein adjusting the amount of the filtered output comprises adjusting an amount of the second gas in the filtered output.

6. The method of claim 5, wherein adjusting the amount of the second gas in the filtered output comprises adding additional second gas to the filtered output.

7. The method of claim 1, wherein adjusting the amount of the filtered output comprises adjusting an amount of the first gas in the filtered output.

8. The method of claim 7, wherein adjusting the amount of first gas in the filtered output comprises adding additional first gas to the filtered output.

9. The method of claim 1, further comprising temporarily storing the filtered output before adjusting the amount of the filtered output.