Abstract:
A plasma torch is provided and adapted to generate very high operating temperatures to gasify various types of materials, such as biomass materials and various carbonaceous materials. The plasma torch is composed of a ceramic body that has first, second, and third intersecting bores. Each of the first, second, and third intersecting bores defines a threaded portion therein. A first and second tungsten carbide electrode is adjustably disposed in the first and second intersecting bores and operative to be adjustable to establish a controlled gap size therebetween. A compressed gas connection is threadably disposed in the threaded portion of the third bore and is operative to introduce a flow of compressed gas through the controlled gap. The first and second tungsten carbide electrodes are connectable to a source of electrical energy and functions to produce an electrical arc across the controlled gap. The resulting flame produced by the electrical arc burns at an extreme temperature.

Description:
TECHNICAL FIELD  
       [0001]    This invention relates to the apparatus and application of a plasma torch used for the gasification of biomass fuels, copper, aluminum, carbonaceous, etc. 
       BACKGROUND  
       [0002]    Various plasma torches are known and available. Many are used to cut thin metals for the production of metal art while others are used in furnaces to melt or gasify materials such as coal, metal, copper, aluminum, biomass and other types of materials. Some plasma torch furnaces are used to produce fine powders, such as, aluminum powders. Many applications of plasma torches uses temperatures under 1000 degrees C., while other applications may go up to 7,000 degrees C. to 10,000 degrees C. In all of the noted applications, the plasma torch(s) used are based on the same principles. A body is provided that has two different electrodes disposed therein spaced from one another at a predetermined fixed distance. By directing electrical current through one of the electrodes (anode), an arc is generated from the anode to the other electrode (cathode). By directing a known gas across the space between the anode and the cathode, a high temperature plasma flame is generated. Various metals have been used in the past to make plasma torches. Generally the body is made of a metal and utilizes various forms of cooling systems to remove the high heat from the body that is absorbed during the melting process. The added cooling systems are both costly and bulky. It would be advantageous to have a plasma torch that does not require a complicated cooling system and can operate at higher temperatures. 
         [0003]    The electrodes that are used in known plasma torches are typically made from high conductivity metals, such as, copper, aluminum, silver, graphite and various combinations of these metals. Some known combinations are copper/aluminum, copper/silver, and copper/graphite. Likewise, hard coatings, such as tungsten surface coating, have been applied to different metals to provide a surface that can more readily resist the extreme heat and wear resulting from continued exposure to the arc generated between the electrodes. 
         [0004]    Various problems and disadvantages have been experience by using various ones of the known plasma torches. The life of the known plasma torches is one of the problems. Many known plasma torches last only 220-400 hours during continued usage. As the operating temperature is increased, the life of the plasma torch is decreased. Most known high temperature plasma torches are limited to an operating temperature of generally up to 10,000 degrees C. At such high operating temperatures, the generated arc between the electrodes cause high wear on the surfaces of the electrodes. Since the electrodes are secured in a permanent position, it is time consuming and costly to replace the electrodes. Many times it is necessary to replace the entire plasma torch. As can be appreciated, by increasing the current and amperage, the wear on the electrodes will likewise increase. It is desirable to have a plasma torch that will overcome one or more of the problems or disadvantages set forth above. 
       SUMMARY OF THE INVENTION 
       [0005]    According to the present invention, a plasma torch is provided wherein the body is made of a ceramic material and has a first bore, a second bore, and a third bore, each intersecting with each other. A first threaded portion is defined in the first bore, a second threaded portion is defined in the second bore and a third threaded portion is defined in the third bore. A first tungsten carbide electrode having an external threaded portion is threadably disposed in the first threaded portion of the first bore, a second tungsten carbide electrode having an external threaded portion is threadably disposed in the threaded portion of the second bore and a compressed gas fitting is threadably disposed in the threaded portion of the third bore. 
         [0006]    The use of a ceramic body allows the use of the subject plasma torch without the need of a complicated cooling system. Likewise, with the use of tungsten carbide electrodes, high wear on the electrodes, from the generated arc, is lessened. Furthermore, the ease in adjusting the electrodes relative to each other eliminates the need to change the electrodes so often. The ease of adjusting also permits the flexibility of adjusting the generated arc for the most optimal arc generation Additionally, the electrodes may be quickly changed while also securing the electrodes in a desired position. The subject plasma torch can operate at higher temperatures than others, be used for longer periods of time and has a longer life than others. 
         [0007]    Other objects, features, and advantages of the subject concept will become more apparent from the following detailed description of the preferred embodiments and certain modification thereof when taken together with the accompanying drawings. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0008]      FIG. 1  illustrates a cross-sectional view of the ceramic body taken through the respective two electrodes; 
           [0009]      FIG. 2  illustrates a cross-sectional view of the ceramic body taken through one of the two electrodes and the compressed gas bore and being generally perpendicular to the view of  FIG. 1 ; 
           [0010]      FIG. 3  illustrates one of the electrodes; 
           [0011]      FIG. 4  illustrates another of the electrodes; 
           [0012]      FIG. 5  illustrates another embodiment of a cross-sectional view of the ceramic body taken through the respective bores of the two electrodes and the compressed gas bore; and 
           [0013]      FIG. 6  illustrates a cross-sectional view of the ceramic body taken through the electrode bores and being generally perpendicular to the view of  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    Referring to  FIGS. 1 &amp; 2 , a general representation of a plasma torch  10  is disclosed and includes a ceramic body  12 , a first tungsten carbide electrode  14  adjustably disposed in the ceramic body  12 , a second tungsten carbide electrode  16  adjustably disposed in the ceramic body  12  and a compressed gas connection  18  disposed in the carbide body. Also illustrated is a source  19  of electrical energy and associated positive and negative connections  20 , 21 . The positive and negative connections  20 , 21  are connected to the respective ones of the first and second tungsten carbide electrodes  14 , 16 . 
         [0015]    A first bore  22  is defined in the ceramic body  12  and extends from one side  23  thereof into the ceramic body  12 . A second bore  24  is defined in the ceramic body  12  and extends from a second side  26  thereof into the ceramic body  12 . The second bore  24  intersects with and extends beyond the first bore  22 . A third bore  30  is defined in the ceramic body  12  and intersects with both the first and second bores  22 , 24 . The location of the intersection of the third bore  30  with respect to each of the first and second bores  22 , 24  is generally perpendicular with each. The third bore  30  extends from a third side  32  of the ceramic body  12  to an opposed, fourth side  34  thereof. A center line  36  of the second bore  24  is defined in the ceramic body  12  and is offset nearer to the third side  34  than a center line  38  of the first bore  22  ( FIG. 3 ). The ceramic body  12 , as illustrated in  FIGS. 1 &amp; 2 , has a generally multi-sided shape. However, it is recognized that the shape could be cylindrical, tubular or hexagonal. 
         [0016]    A first internally threaded insert  42  is disposed in the first bore  22  of the ceramic body  12  generally adjacent the first side  23 , a second internally threaded insert  44  is disposed in the second bore  24  of ceramic body  12  generally adjacent the second side  26  and a third internally threaded insert  46  is disposed in the third bore  30  of the ceramic body  12  generally adjacent the third side  32 . It is recognized that the internal threads of each of the first, second, and third internally threaded inserts  42 , 44 , 46  could be formed directly in the ceramic body  12  without departing from the essence of the subject invention. 
         [0017]    Referring to  FIG. 3 , the first tungsten carbide electrode  14  is more clearly illustrated. The first tungsten carbide electrode  14  has a threaded portion  50  disposed on the perimeter thereof and extends from one end  51  thereof a predetermined distance. The remaining distance to an opposed end  52  thereof has a reduced diameter that is operative to permit the reduced diameter to slide within the first bore  22  of the ceramic body  12 . A slot  54  is defined in the one end  51  of the first tungsten carbide electrode  14  adjacent the threaded portion  50  and operative to permit easy adjustment of the first tungsten carbide electrode  14  within the first bore  22 . The opposed end  52  of the first tungsten carbide electrode  14  has a generally bullet shaped nose  56  as illustrated. It is recognized that the shape could vary from the bullet nose shape  56  to a flat nose without departing from the essence of the subject invention. In the embodiment illustrated in  FIGS. 1 &amp; 2 , the first tungsten carbide electrode  14  could serve as the anode. 
         [0018]    Referring to  FIG. 4 , the second tungsten carbide electrode  16  is illustrated more clearly. The second tungsten carbide electrode  16  has a threaded end portion  60  disposed on the perimeter thereof and extends from one end  61  thereof a predetermined distance. The remaining distance thereof to an opposed end  62  has a reduced diameter that is operative to permit the reduced diameter to slide within the second bore  24  of the ceramic body  12 . A slot  64  is defined in the one end  61  of the first tungsten carbide electrode  16  adjacent the threaded end portion  60  and operative to permit easy adjustment of the second tungsten carbide electrode  16  within the second bore  24 . The opposed end  62  of the second tungsten carbide electrode  16  has a generally flat shape  66  as illustrated. It is recognized that the shape could vary from the flat shape and to a bullet nose shape without departing from the essence of the subject invention. In the embodiment illustrated in  FIGS. 1 &amp; 2 , the second tungsten carbide electrode  16  could serve as the cathode. 
         [0019]    The first tungsten carbide electrode  14  is threadably received in the internal threads of the first internally threaded insert  42  and is operative to move further into or out of the first bore  22  to establish a desired distance between the opposed end  52  thereof and the side of the second tungsten carbide electrode  16 . The second tungsten carbide electrode  16  is threadably received in the internal threads of the second internally threaded insert  44  and is operative to move further into or out of the second bore  24  to expose an unused portion of the reduced diameter of the second tungsten carbide electrode  16  to the opposed end  52  of the first tungsten carbide electrode  14 . Since the first and second tungsten carbide electrodes  14 , 16  are substantially pure tungsten carbide, they will wear better and more efficiently conduct the electrical energy therethrough. In addition, the compressed gas connection is threadably disposed in the third internally threaded insert  46 . The compressed gas connection is operatively connected to a source of compressed gas. The source of compressed gas could be various types or combinations of compressed gas, for example, such as; air, nitrogen, noble gases, etc. It is recognized that the first and second tungsten carbide electrodes  14 , 16  could be interchangeably used as the anode and cathode. 
         [0020]    As illustrated in  FIG. 1 , the first tungsten carbide electrode  14  is connected to the source  19  of electrical energy by a positive electrical connection  20 . The second tungsten carbide electrode  16  is connected to the source  19  of electrical energy by a negative electrical connection  21 . The source  19  of electrical energy has the controls therein that are operative to control the voltage and the amperage as desired. 
         [0021]    Referring to  FIGS. 5 &amp; 6 , another embodiment is illustrated. Like elements have like element numbers. Element numbers having a prime (′) attached indicates similar elements from  FIGS. 1 &amp; 2  having modifications made to them. The first bore  22  of  FIGS. 5 &amp; 6  is the same as that of  FIGS. 1 &amp; 2 . However, the second bore  22 ′ of  FIGS. 5 &amp; 6  is diametrically opposed to the first bore  22 . They still intersect with each other but on a common plane. The third bore  30 ′ of  FIGS. 5 &amp; 6  is basically the same as that of  FIGS. 1 &amp; 2  with the exception that the third bore  30 ′ is reduced in size near the exit to the opposed side  26  of the ceramic body  12 . The third bore  30 ′ intersects the first and second bores  22 , 24 ′ at their intersection point and along the same plane as illustrated. 
         [0022]    The first tungsten carbide electrode  14  and the second tungsten carbide electrode  16 ′ of  FIGS. 5 &amp; 6  are substantially the same and are each connected to the source  19  of electrical energy by the respective positive and negative electrical connections  20 , 21  in the same manner. It is recognized that the bullet nose shape  56  of each tungsten carbide electrode  14 , 16 ′ could be different without departing from the essence of the subject invention. 
         [0023]    It is recognized that various types of electrical connections  20 , 21  could be used to connect the source  19  of electrical energy to the first and second tungsten carbide electrodes  14 , 16 . Likewise, various known systems/apparatus could be used to vary the voltage and amperage being directed to the first and second tungsten carbide electrodes  14 , 16  of the subject plasma torch  10 . 
       INDUSTRIAL APPLICABILITY  
       [0024]    The subject plasma torch  10  provides an efficient, high temperature, long lasting and self-cooled plasma torch. During operation, electrical energy is directed through the positive electrical connection  20  to the first tungsten carbide electrode  14  (anode) and the negative electrical connection  21  provides a path for the electrical energy to return to the source  19  to complete the electrical path. As a result of the controlled spacing between the anode  14  and the second tungsten carbide electrode  16  (cathode), an optimal spark is generated therebetween. 
         [0025]    By passing the compressed gas through the connection  18 , through the third bore  30 , and through the generated arc between the first and second tungsten carbide electrodes  14 , 16  as controlled by the gap therebetween, a plasma gas/flame is produced. Based on the voltage and amperage, the intensity of the produced plasma flame is controlled. As previously set forth, the produced plasma flame can produce operating temperatures well in excess of 10,000 degrees C. As the duration of the plasma torch  10  being used continues for long periods of time, it may be necessary to adjust one or both of the first and second tungsten carbide electrodes  14 , 16 . The adjustment will once again optimize the electrical arc being generated between the first and second tungsten carbide electrodes  14 , 16 . By using the subject plasma torch  10 , the total life thereof far exceeds known plasma torches. 
         [0026]    The subject plasma torch  10  can be utilized to gasify various types of materials, such as biomass and many different types of carbonaceous materials. Since the operating temperatures of the subject plasma torch is so high, the gasified gases (syngas) is very clean as compared to other plasma torches. This is true because the extremely high operating temperatures vaporize many of the unwanted gases that are normally present in produced syngas. By vaporizing many unwanted gases from the syngas, additional steps are not needed to remove them in order to attain the desired syngas that has a desired relationship between the retain hydrogen and carbon monoxide gases. 
         [0027]    Other embodiments as well as certain variations and modifications of the embodiments herein shown and described will obviously occur to those skilled in the art upon becoming familiar with the underlying concept. It is to be understood, therefore, that the subject design may be practiced otherwise than so specifically set forth above.