Abstract:
A needle valve is disclosed for controlling the quantity of a halide vapor to be injected into a liquid metal. The needle valve may seat in a supersonic nozzle from which the halide vapor exits. Various products made with the apparatus of the invention are disclosed.

Description:
RELATED APPLICATIONS  
       [0001]     This application, pursuant to 37 C.F.R. 1.78(c), claims priority based on provisional application U.S. Provisional Application Ser. No. 60/408,924 filed Sep. 7, 2002 and U.S. Provisional Application Ser. No. 60/408,825 filed Sep. 7, 2002 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     This invention relates to the Armstrong process as described in U.S. Pat. Nos. 5,779,761, 5,958,106 and 6,409,797, the disclosures of each of which is incorporated herein by reference. As illustrated in the above-referenced patents, a reductant metal and a halide of the metal to be produced are introduced into a reactor chamber. For instance, in the &#39;106 patent, a sodium stream from a source of sodium is pumped by a pump  11  into a reaction chamber  14 . Titanium tetrachloride from a source thereof is fed by a pump  21  to a boiler  22 . From the boiler  22 , titanium tetrachloride vapor is also pumped to the reaction chamber  14 .  
         [0003]     The present invention relates in general to the Armstrong Process as described above but also more specifically to the reactor used in converting a halide vapor into a powder, either of ceramic or metal or alloy. More particularly, the invention relates in part to a needle valve used to introduce halide vapor into the liquid metal, such as sodium, providing significant advantages to the Armstrong Process. In another aspect of the invention, a supersonic nozzle is used for the introduction of the halide vapor to improve the mixing of the vapor with the liquid, reducing the expansion of the gas into the liquid which occurs with a sonic nozzle, thereby modifying the reactions advantageously.  
       SUMMARY OF THE INVENTION  
       [0004]     Accordingly, an object of the present invention is to provide an apparatus for injecting halide vapor into a liquid metal in which a needle valve is used to carefully meter the amount of vapor introduced into the liquid metal.  
         [0005]     Still another object of the invention is to provide an apparatus for introducing a halide vapor into a liquid metal environment in which a supersonic nozzle is employed.  
         [0006]     Another object of the invention is to provide an apparatus and system for injecting a halide vapor subsurface of a liquid metal, comprising inner and outer conduits forming an annulus there between, a needle valve interior of the inner conduit movable axially thereof between an open position in which the inner conduit is in fluid communication with the outer conduit and a closed position in which the inner conduit is sealed from the outer conduit, a supply of halide vapor in fluid communication with the inner conduit, a supply of liquid metal in fluid communication with the outer conduit, and an actuator assembly connected to the needle valve for moving the needle valve axially of the inner conduit between the open and sealed positions thereof, whereby introduction of halide vapor into liquid alkali or alkaline earth metal or mixtures thereof present in the annulus results in an exothermic reaction controlled at least in part by the axial position of the needle valve.  
         [0007]     A still further object of the present invention is to provide an apparatus and system of the type set forth incorporating a supersonic nozzle.  
         [0008]     Another object of the present invention is to provide a system for making a powder by the exothermic reduction of a halide vapor with an alkali metal or an alkaline earth metal or mixtures thereof, comprising a supply of liquid alkali or alkaline earth metal or mixtures thereof, a supply of a halide vapor, an apparatus for injecting the halide vapor subsurface of the liquid metal having inner and outer conduits forming an annulus therebetween, a needle valve interior of the inner conduit movable axially thereof between an open position in which the inner conduit is in fluid communication with the outer conduit and a closed position in which the inner conduit is sealed from the outer conduit, the supply of halide vapor being in fluid communication with the inner conduit, the supply of liquid metal in being fluid communication with the outer conduit, and an actuator assembly connected to the needle valve for moving the needle valve axially of the inner conduit between the open and sealed positions thereof, whereby introduction of halide vapor into liquid alkali or alkaline earth metal or mixtures thereof present in the annulus results in an exothermic reaction controlled at least in part by the axial position of the needle valve producing the powder and the halide salt of the liquid metal.  
         [0009]     Still another object of the present invention is to provide a system of the type previously set forth using a supersonic nozzle without a needle valve to introduce the halide vapor into the liquid metal.  
         [0010]     A final object of the present invention is to provide powder made by the operation of the apparatus and systems disclosed, the powder being a ceramic, a metal or an alloy with or without conversion to a solid product from the powder.  
         [0011]     The invention consists of certain novel features and a combination of parts hereinafter fully described, illustrated in the accompanying drawings, and particularly pointed out in the appended claims, it being understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0012]     For the purpose of facilitating an understanding of the invention, there is illustrated in the accompanying drawings a preferred embodiment thereof, from an inspection of which, when considered in connection with the following description, the invention, its construction and operation, and many of its advantages should be readily understood and appreciated.  
         [0013]      FIG. 1  is a schematic representation of a system for practicing the present invention;  
         [0014]      FIG. 2  is a schematic representation of a needle valve assembly useful in the present invention; and  
         [0015]      FIG. 3  is a schematic representation of a supersonic nozzle useful in the practice of the present invention. 
     
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT  
       [0016]     Referring to  FIG. 1  of the drawings, there is disclosed a system  10  for the practice of the present invention including a supply of halide vapor  15  which in turn is in fluid communication with a plurality of liquid halide or solid halide materials, shown for purposes of illustration only as supplies  16 ,  17  and  18  for halide liquids or solids A, B and C respectively. The system  10  further includes a supply of liquid metal  20  which may be any alkali or alkaline earth metal or various mixtures thereof, sodium and magnesium being preferred with sodium being mostly preferred.  
         [0017]     Similarly, with respect to the halide vapor supply  15 , chlorides are preferred.  
         [0018]     There is further provided a separation vessel  30  in fluid communication with a reactor assembly  50 , as will be described and the separation vessel  30  is also in fluid communication with a drying and passivating vessel  40 . A powder product outlet  45  is in fluid communication with the drying and passivating vessel  40 , as will be described, is either the final product or the intermediate product of the system and process of the invention.  
         [0019]     The present invention and system  10  includes the reactor assembly  50 , as seen in  FIG. 2 , which has an outer cylinder  51  having an exit portion  52  which may be of reduced diameter or of the same diameter as the remainder of the outer cylinder or conduit  51 , as preferred.  
         [0020]     The reactor assembly  50  serves to receive the halide of the metal or ceramic to be produced and the liquid reducing metal and to introduce the halide in a controlled fashion subsurface of the reducing metal or into a stream of the reducing metal so that the temperature of the reaction is controlled, in part, by the excess of the reducing metal, all is taught in the above-referenced patents.  
         [0021]     The reactor assembly  50  has one-half of a sealing ring  54  on the exit nozzle portion  52  to sealing engage another sealing ring (not shown) located in the vessel into which the exit portion  52  is positioned. The outer cylinder  51  also has a inlet nozzle portion  56  which terminates in an end  57 . An actuator  60 , either pneumatic or otherwise, as is known in the art, is in communication with the reactor assembly  50  and particularly the outer cylinder  51  as will be explained. The outer cylinder  51  also has a pressure tap  62  which may be for the introduction of an inert gas such as argon or to vent the assembly  50 , if required, or to monitor the pressure within the outer cylinder  51 . Also provided is a reducing metal inlet  64 , in the illustration a sodium inlet. Both the pressure tap  62  and the reducing metal inlet  64  extend through the outer cylinder  51  and are sealed thereto.  
         [0022]     A sealing ring is made up of mating halves  66  and  67  intermediate the actuator  60  and the exit nozzle portion  52  of the reactor assembly  50 . A halide inlet tap  69  extends into the inlet nozzle portion  56  of the outer cylinder  51  and is sealed downstream of the inlet  69  by means of the sealing rings  66 ,  67  and is in fluid communication with a housing  79  which may be generally cylindrical in shape and extends from the sealing half ring  66  through the outer cylinder  51  and terminates at an end  81  having a valve seat therein.  
         [0023]     A needle valve  75  includes an elongated cylindrical shaft portion  76  having a conical shape valve portion  77  and another end  78  in communication with the actuator  60 . The halide inlet  69  introduces halide vapor into the chamber formed by the inlet nozzle portion  56  of the outer cylinder  51  and enters the housing  79  by virtue of the communication between the end of the housing  79  and the sealing rings  66 ,  67 . The sodium entering through sodium inlet  64  is on the outside of the housing  79  and completely fills the outer cylinder  51  and flows axially of the outer cylinder. The longitudinal axial movement of the needle valve  75  by means of the actuator  60  causes the conical end portion  77  to seat within a valve seat in the end  81  of the housing  79 , it being apparent to those of ordinary skill in the art that the diameter of the valve seat in the end  81  must be smaller than the diameter of the shaft portion  76  of the needle valve  75 . Valve seats  81  between  1 / 8  and  {fraction (3/8)} inch have been used with the appropriate change in shaft portion 76.    
         [0024]     As stated in the above referenced patents, it is important that no sodium be able to back up through the valve seat in the end  81  into the halide vapor supply. That necessity is accomplished by using at least sonic flow of the halide through reactor assembly  50  as taught in the referenced patent. As the actuator  60  is operated to move the shaft portion  76  axially of outer cylinder  51  to the right in  FIG. 1  so that the conical portion  77  of the needle valve  75  begins to seat within the valve seat in the end  81 , the amount or volume of halide vapor, such as titanium tetrachloride, introduced into the sodium or reducing metal inside the outer cylinder  51  is reduced or controlled permitting the operators of the system to vary the time and rate of delivery of the halide vapor. Another advantage of the needle valve  75  is that when the needle valve  75  is fully seated within the valve seat in the end  81 , a vacuum may be drawn upstream of the nozzle or reactor assembly  50  before startup of the production of the metal by the exothermic reaction of the halide with the reducing metal.  
         [0025]     Referring now to  FIG. 3 , there is disclosed a supersonic nozzle  5  including an elongated housing  86  having a first larger diameter  87  and a throat  88 . The terminal or distal diameter  89  is larger than the throat  88  and smaller than the internal diameter  87 , all as well known in the art. Representative but not limiting dimensions are on  FIG. 3 , the arrow  90  being indicative of the gas flow through the nozzle  85 .  
         [0026]     The use of a supersonic nozzle  85  distinguished to a sonic nozzle is an improvement to the process disclosed in the above captioned patents. The supersonic nozzle  85  alters the flow pattern of the halide gas flow  90  and permits the halide gas to flow at a higher velocity at the entry point to the reductant metal. Also, the use of a supersonic nozzle  85  reduces the expansion of the halide gas as it enters the reductant metal thereby altering the size and shape of the reaction zone.  
         [0027]     More specifically, when using a sonic nozzle, the vapor exiting the nozzle is at an over pressure condition which causes it instantly to expand at the end of the nozzle as the gas enters the liquid reductant. The use of a supersonic nozzle  85  ( FIG. 3 ), permits the gas to exit the nozzle without being in an over pressurized condition and without the subsequent expansion associated with a sonic nozzle. By virtue of the use of the supersonic nozzle  85 , a modified reaction zone is obtained in which various size and morphology characteristics of the product powder are altered and may also reduce the oxygen content of the powder produced. Designs of supersonic nozzles  85  are well known, the  FIG. 3  shows a nozzle  85  having slightly larger diameter exit point  89  than the smallest diameter of the nozzle throat  88 . Specifically, the exit diameter  89  of the nozzle  85  is 0.239 inches plus or minus 0.002 inches, and the narrowest part of the throat  88  is 0.219 inches plus or minus 0.002 inches. The invention is applicable to reductions of various halides with a wide variety of reductant metals, all as set forth in the above three referenced patents.  
         [0028]     Referring again to  FIG. 1 , it is seen that the powder product  45  discharged from the drying and passivating vessel  40  may be used as a product in and of itself or may be used in powder metallurgy to produce product or ingot or other means by which solid product is formed which also includes casting, extruding or other methods. Any solid product or object made from the powder  45  produced by the inventive system  10  is within the purview of the present invention.  
         [0029]     While there has been disclosed what is considered to be the preferred embodiment of the present invention, it is understood that various changes in the details may be made without departing from the spirit, or sacrificing any of the advantages of the present invention.