PATENT ABSTRACT
An apparatus for destroying the contaminants found in contaminated soil prior to soil reclamation. The apparatus preferably includes three major sections or components and they are: a soil infeed section, a heating section, and a soil extraction section. The preferred infeed section includes a hopper placed in conjunction with an incline conveyor and a distally positioned dump chute. The heating section has a material receptacle in the form of a material receiving chute, a heater disposed adjacent to the interior of a longitudinal spirally internally veined rotating drum which communicates with the third section, which is a material extraction or expulsion section also in the form of an incline conveyor and a chute. The heater section includes a heater station which enables a supply of propane or LP gas to be connected thereto and ignited to fire heat the internal chamber of the rotating drum. The heating enables the contaminants such as hydrocarbons to be burned from contaminated soil.

PATENT DESCRIPTION
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates generally to apparatuses and methods for the removal of contaminates, such as hydrocarbons, from soil, and more particularly those apparatuses used to raise the temperature of soil containing the contaminate (e.g., hazardous, volatile hydrocarbons) to facilitate the removal thereof. The present apparatus and method is also believed to be particularly well suited for the removal of hydrocarbon contaminants from soil, clay, silt, or sand, etc.  
           [0003]    2. Description of the Related Art.  
           [0004]    Growing environmental awareness has caused recognition of the potential environmental and health hazards associated with soil that has become contaminated with hydrocarbons. Tanks for storing hydrocarbons such as crude oil or products such as gasoline or diesel sometimes develop leaks resulting in discharge of a portion of their contents into the surrounding soil. Over time the hydrocarbons can accumulate in the soil eventually causing contamination of nearby water supplies.  
           [0005]    Solids can also accumulate within the tanks themselves. Over time, these solids can form an emulsion of solids and hydrocarbons often referred to as sludge. This sludge generally forms a layer at the bottom of a tank that must eventually be removed. An inexpensive way for decontaminating such sludge or contaminated soil is desirable.  
           [0006]    Many techniques have been developed to remediate soil and groundwater which becomes contaminated with, for example, hydrocarbons. Some techniques are limited to the remediation of soil only and others remediate both the soil and the underlying groundwater.  
           [0007]    “Vapor extraction” is a common method of environmental remediation. This method draws vapors containing volatile hydrocarbons from the soil. As these vapors are withdrawn from the soil, the quantity of hydrocarbons remaining in the soil and the underlying groundwater is gradually reduced. When vapor extraction is conducted long enough, the quantity of hydrocarbons remaining in the soil and groundwater are reduced to a point which is considered non-threatening to the public health. When the vapors are drawn from the soil and exhausted into the atmosphere, with or without treatment, the method is called “open-loop”. When the vapors are drawn from the soil, treated, and pumped back down into the soil, the method is called “closed-loop”.  
           [0008]    Because the vapors drawn from the soil often contain hazardous hydrocarbons, local, state, or federal environmental regulations may require that the vapors be treated to prevent air pollution. When the treatment equipment generates heat, and this heat is used to heat the treated vapors prior to injecting them back into ground, the process is called “closed-loop, thermally-enhanced vapor extraction”. The heated vapors slowly raise the temperature of the contaminated soil, thereby enhancing the vaporization of the remaining hydrocarbons in the soil.  
           [0009]    “Pump and treat” is a common method of remediating contaminated groundwater. It uses a pump to extract contaminated groundwater from the ground. The extracted groundwater is treated to remove the dissolved and floating hydrocarbons before being discharged to a local sewer or surface water.  
           [0010]    The prior art can be conveniently divided into four groups: closed-loop technologies, both thermally-enhanced (thermal) and non-thermally-enhanced (non-thermal); and open-loop technologies, both thermal and non-thermal. Techniques in these categories have been developed to simultaneously treat both soil and groundwater, groundwater only, soil only, and free (hydrocarbon) product only. The present invention is concerned primarily with the treatment of soil only or in combination with only trace amounts of ground water.  
           [0011]    Soil Only  
           [0012]    Technologies which treat soil only include: a closed-loop, thermal process disclosed in U.S. Pat. No. 4,982,788, titled “Apparatus and Method for Removing Volatile Contaminants from the Ground” issued on Jan. 8, 1991 to Donnely; two closed-loop, non-thermal processes disclosed in U.S. Pat. No. 4,890,673, titled “Method for Removing Volatile Contaminants from Contaminated Earth Strata” issued on Jan. 2, 1990 to Payne, and that disclosed in U.S. Pat. No. 4,730,672, titled “Method of Removing and Controlling Volatile Contaminants from the Vadose Layer of Contaminated Earth” issued on Mar. 15, 1988 to Payne; and an open-loop, non-thermal process disclosed in U.S. Pat. No. 4,886,119, titled “Method of and Arrangement for Driving Volatile Impurities from the Ground” on Dec. 12, 1989 to Bernhardt et al; in U.S. Pat. No. 4,842,448, titled “Method of Removing Contaminants from Contaminated Soil In Situ” on Jun. 27, 1989 to Koerner et al., and in U.S. Pat. No. 4,660,639, titled “Removal of Volatile Contaminants from the Vadose Zone of Contaminated Ground” on Apr. 28, 1987 to Visser et al.; and in U.S. Pat. No. 4,593,760, titled “Removal of Volatile Contaminants from the Vadose Zone of Contaminated Ground” on Jun. 10, 1986 to Visser et al.  
           [0013]    Soil and Groundwater  
           [0014]    Technologies which simultaneously treat both soil and groundwater include: a closed-loop, non-thermal process disclosed in U.S. Pat. No. 4,966,564 and entitled “Soil and Groundwater Remediation System” which issued Oct. 30, 1990 to Carberry; an open-loop, thermal process disclosed in U.S. Pat. No. 5,018,576 entitled “Process for In Situ Decontamination of Subsurface Soil and Groundwater” issued on May 28, 1991 to Udell et al.; and an open-loop, non-thermal process disclosed in U.S. Pat. No. 5,050,676 entitled “Process for Two Phase Vacuum Extraction of Soil Contaminants” issued on Sep. 24, 1991 to by Hess et al., in U.S. Pat. No. 4,945,988 entitled “Apparatus and Process for Removing Volatile Contaminants From Below Ground Level” issued on Sep. 24, 1991 to Payne et al., and in U.S. Pat. No. 4,832,122 entitled “In-Situ Remediation System and Method for Contaminated Groundwater” issued on May 23, 1989 to Corey et al.  
           [0015]    Some of the above technologies use concepts found in processes developed to remove crude oil and other fuel hydrocarbons from the ground. These processes are summarized as follows:  
           [0016]    Hydrocarbon Removal  
           [0017]    Technologies which remove hydrocarbons from the ground include: closed-loop, thermal processes disclosed in U.S. Pat. No. 3,881,551, titled “Method of Extracting Immobile Hydrocarbons” issued on May 6, 1975 to Terry et al. and disclosed in U.S. Pat. No. 4,303,127, titled “Multistage Clean-Up of Product Gas from Underground Coal Gasification” issued on Dec. 1, 1981 to Freel et al.; and an open-loop, thermal process disclosed in U.S. Pat. No. 4,474,237, titled “Method for Initiating an Oxygen Driven In-Situ Combustion Process” issued on Oct. 2, 1984 to Shu; and an open-loop, non-thermal process disclosed in U.S. Pat. No. 4,369,839, titled “Casing Vacuum System” issued on Jan. 25, 1983 to Freeman et al. and disclosed in U.S. Pat. No. 4,345,647, titled “Apparatus to Increase Oil Well Flow” issued on Aug. 24, 1982 to Carmichael.  
           [0018]    Of the technologies cited above, six are closed-loop processes, of which three are thermal. Two of the three thermal technologies are used exclusively to recover hydrocarbon fuels; only one is known to be used for environmental remediations. In the thermal process cited above by Terry et al., it is not used for the environmental remediation of either soil or groundwater. Rather, it is used to extract a hydrocarbon fuel from deep beneath the earth. The process recirculates a heated fluid through a formation containing a solid hydrocarbon fuel. As the heated fluid passes through the formation, the solid fuel melts and flows through the formation to a well where it is pumped to the surface. The heat transfer medium is a liquid.  
           [0019]    In addition, there are fourteen open-loop processes, of which only two are thermal. Of the two thermal processes, one is used to recover hydrocarbon fuels, and one is used for environmental remediations.  
           [0020]    Only two of the above processes, whether open or closed loop, are used for environmental remediation and employ heat. Donnelly employs a combination of heat from a heat pump and an independent electric coil to heat air drawn from contaminated soil before it is reinjected into the ground. Udell et al. simply injects live steam into the ground.  
           [0021]    The technologies cited above which are used to recover hydrocarbon fuels employ heat by either circulating a heated fluid through the geological formation containing the fuel or by igniting the formation itself. Terry et al. circulates a heated fluid; Freel et. al. and Shu ignite the formation. Both are inefficient and are not effective for soil remediation.  
           [0022]    In general, the above references fall short of the goals of performing adequate soil remediation for several reasons. For example, the non-thermal processes for remediating contaminated soil developed by Carberry, Morrow, Hess et al., Payne et al., Corey et al., Payne, Bernhardt et al., Koerner et al., and Visser et al. are generally limited to more volatile hydrocarbons such as those found in gasoline.  
           [0023]    Although the processes developed by Udell et al. and Donnelly do heat the soil, they are substantially complex and quite expensive to operate. In the case of Udell et al., steam is injected into the ground where it condenses. The condensing steam heats the soil and volatilizes high-boiling hydrocarbons, but as the condensed steam migrates vertically through the soil, it leeches hydrocarbons out of the soil. When the condensed steam reaches the underlaying water table it contaminates the groundwater. Special ground-water extraction wells are needed to extract and treat the contaminated groundwater from the ground. The cost of operating the steam boilers and extracting and treating the contaminated groundwater is very substantial. Further, none of the energy contained in the hydrocarbons removed from the soil is used to operate the process.  
           [0024]    The process developed by Donnelly is also expensive to operate, and, again, none of the energy contained in the hydrocarbons removed from the soil is used to operate the process. The Donnelly process has the additional limitation of using a refrigerated coil to remove hydrocarbons from vapors drawn from the soil before these vapors are heated and reinjected back into the soil. Unless the refrigerated coil is operated in the cryogenic temperature range which would capture all of the hydrocarbons, which is unlikely due to the prohibitive cost, the vapors reinjected into the ground will contain significant amounts of hydrocarbons. Consequently, the Donnelly process actually recirculates hydrocarbons through the soil. This scheme limits the extent of remediation which can be achieved.  
           [0025]    In a typical soil remediation, the soil is often a mixture of sand, silts, and clays which may be present in discrete layers, called lenses. When this soil is remediated using non-thermal vapor extraction, as demonstrated by the patents cited above, the hydrocarbons held by the silts and clays are very difficult to remove. Due to their high surface areas, clays and silts have a strong affinity for hydrocarbons and retard their volatilization.  
           [0026]    It is preferred that the equipment for decontaminating such sludge or soil be somewhat portable so that it can be taken to the site of contamination, avoiding the relatively expensive process of moving large quantities of solids to a central processing facility.  
         SUMMARY OF THE INVENTION  
         [0027]    The present invention can be summarized as heating apparatus capable of receiving soil for decontamination treatment. The invention can be stationary or mobile. The mobile embodiment includes a towable frame structure in the nature of a wheel mounted trailer with trailer hitch configuration suitable for engagement with a motorized vehicle enabling it to be towed from place to place.  
           [0028]    The preferred embodiment of the present invention generally includes several distinct sections operably interconnected to carry out the soil decontamination process. One of the sections includes a hopper and an inclined conveyor. The conveyor preferably further includes a series of spaced apart transverse flights positioned across the surface of the conveyor belt which enables the soil to be carried upward and dumped into the next section. The next section is the heating section and includes a heating chamber or burner.  
           [0029]    The heating section generates a high heat within the interior of a cylindrical chamber. The selected temperature is sufficient to ignite the contaminants such as and destroy them. The high heat is preferably produced by a propane or LP gas flame blower configuration directed into the interior of a rotating steel cylinder. The flame raises the internal temperature of the steel cylinder and the exterior of the steel cylinder is shielded to maintain the efficiency of the system.  
           [0030]    When contaminants are introduced into the cylinder of the heating section via an access chute having an inlet and a exit, the high heat causes the temperature of the soil to climb above its burning point, but remain below the melting point. The access chute allows the axial centerline of the cylinder to be offset from the end of the infeed conveyor and thus serves to shield the interior of the cylinder during use.  
           [0031]    The cylinder further includes a series of internally projecting fins attached to its interior surface. The fins help move the soil from the proximal end to the distal end of the rotating declined cylinder during use. The cylinder also includes end plates which form flanges at the proximal and distal ends of the cylinder in order to reduce the size of the interior opening to the cylinder and assist with the efficient heating and processing of the soils.  
           [0032]    An annular ring like flange is also provided adjacent the distal end of the cylinder and protrudes into it to enable the soil exiting the cylinder to be carefully removed without spilling from the cylinder. The annular flange(s) also enable the cylinder to maintain its proper operational alignment atop the declined frame on which it rotates during use.  
           [0033]    Yet another section follows the heating section and preferably includes a hopper which collects the soil which is processed within the heating chamber and carries them from the burner chamber via an exit chute. The exit chute is placed adjacent to an inclined take-away conveyor which is used to carry the processed soil upwardly and out of the confines of the machine for cooling.  
           [0034]    Of course, some considerations must take advantage of the relative height relationship between the first incline conveyor in the preferred embodiment and the dump height of the conveyor with reference to the proximal input flanged and of the rotating cylinder. It is preferred that a variance in height is presented in the event the soils emit flames within the cylinder during processing.  
           [0035]    In addition, a metal, preferably stainless steel heat resistant cover overlies the combination of the steel cylinder and a heat absorbing blanket both of which turn underneath the cover. The cover is provided as a means to insulate the cylinder and reduce the temperature to the touch. The underside of the cover is preferably lined with a heat resistant insulating blanket which further has a tendency to resist heat transfer, enhance the efficiency of the rotating steel cylinder by trapping the heat inside of the burner chamber and therefore surrounding the blanket from which the high heat has a tendency to attempt to escape.  
           [0036]    The preferred embodiment of the mobile version of the present invention positions all three of the primary components on an axled trailer as mentioned above. The axled trailer enables the apparatus to be taken to and removed from the contamination site thereby making the processing of the soil and its reclamation more efficient.  
           [0037]    The present invention may be summarized in a variety of ways, one of which is the following: an apparatus for destroying contaminants in soil, comprising, at least one hopper, conveyor means for transporting the soil to be processed, and a heating chamber assembly further comprising a burner station, a soil infeed portion and a soil removal portion.  
           [0038]    The preferred embodiment preferably further comprises a trailer portion supporting the at least one hopper, the conveyor means and the heating chamber. The conveyor means further includes at least one inclined conveyor having a proximal and distal end, and the heating chamber assembly further includes a heating cylinder and means for rotating the heating cylinder during use.  
           [0039]    The preferred embodiment also includes means for supporting the heating cylinder in a declined position such that the infeed portion of the heating cylinder is higher than the soil removal portion, and preferably includes roller means for maintaining the proper alignment of the cylinder in the proper heating cylinder.  
           [0040]    The preferred embodiment also includes means for preventing the soil from escaping the heating chamber assembly at the soil removal section thereof, and preferably includes a cooperating circumferential plate and annular collar assembly.  
           [0041]    The interior of the heating chamber has spiral flutes to help move the soil from a proximal end to a distal end within the cylinder during use.  
           [0042]    An advantage of the present invention is the ability to destroy the hazardous nature of contaminants such as hydrocarbons associated contaminated soil. An object of the present invention is to provide an apparatus for efficiently destroying and rendering inert the contaminants which become commingled and mixed within prior to soil reclamation and thereby making it possible.  
           [0043]    A feature of the present invention is a heating chamber which preferably comprises a rotating, internally heated, steel cylinder.  
           [0044]    An advantage of the present invention is to provide a rotating steel cylinder the internal confines for which the contaminated soil travels during the heating process and therefore during the step by which the contaminants are heated to destruction. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0045]    [0045]FIG. 1A is an elevated perspective view of the preferred embodiment of the present invention;  
         [0046]    [0046]FIG. 1B is an elevated perspective view of the frame portion of the preferred embodiment of the present invention as shown in FIG. 1;  
         [0047]    [0047]FIG. 2A is an elevated perspective view of the left side of the conveyor infeed portion of the preferred embodiment shown in FIG. 1;  
         [0048]    [0048]FIG. 2B is an elevated perspective view of the right side of the conveyor infeed portion of the preferred embodiment shown in FIG. 1 and opposite the left side as shown in FIG. 2A;  
         [0049]    [0049]FIG. 3A is a rear plan view of the burner section of the preferred embodiment taken in the direction opposite the arrow shown in the right hand margin of FIG. 2B;  
         [0050]    [0050]FIG. 3B is an elevated perspective view of the burner section of the preferred embodiment taken in the direction of the arrow shown in the right hand margin of FIG. 2B;  
         [0051]    [0051]FIG. 4 is an elevated perspective side view of the components shown opposite or behind those shown in FIG. 3B and taken in the direction of the arrow in that figure;  
         [0052]    [0052]FIG. 5 is an elevated perspective end view of the heating cylinder of the preferred embodiment of the present invention;  
         [0053]    [0053]FIG. 6A is an elevated perspective view of the soil removal chute of the present invention shown with an exit port substantially the same size as the cylinder diameter shown in FIG. 5;  
         [0054]    [0054]FIG. 6B is an elevated perspective view of the soil removal chute of the present invention shown with an exit port opening having an optional trap door and having an exit port substantially the same size as the cylinder diameter shown in FIG. 5;  
         [0055]    [0055]FIG. 7 is a side elevated perspective view of the heat blanket surrounding the heating cylinder;  
         [0056]    [0056]FIG. 8 is a side plan view of a portion of the means for preventing soils from escaping the heating cylinder and including cooperating circumferential plate and annular collar assembly;  
         [0057]    [0057]FIG. 9 is an elevated perspective end view of the cover shown in FIG. 1A complete with hanger brackets which facilitates the removal of the cover from the machine; and  
         [0058]    [0058]FIG. 10 is an elevated perspective view of the underside surface of the cover shown in FIG. 9. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0059]    With reference to FIG. 1A, a preferred embodiment of the present invention is designated generally by the reference numeral  10  and includes several sections or subassemblies which can be distinguished from one another by the function or operation of the components shown as designated therein and hereinbelow.  
         [0060]    A trailer portion, designated generally by the reference numeral  12  incorporates a trailer tang  14  with hitch connection  15 , attached to a trailer bed portion  16  having wheeled axles  18  for mobility. The trailer portion  12  also includes a heating chamber frame assembly designated generally by the reference numeral  13  of FIG. 1B.  
         [0061]    Frame assembly  13  has spaced apart ends  17  and  19 , a plurality of upright vertical supports  21 , horizontal frame members  23 , bearing supports  25 , and a frame cover  27 . The bearing supports  25  differ in vertical height in order to provide an imaginary declined plane from end  17  toward end  19  for optimum operable support of the heating chamber section  48  more thoroughly described below.  
         [0062]    A soil input section, designated generally by the reference numeral  20  in FIG. 1A, includes a material hopper  22  having beveled side walls  24 , an interior well  26 , a beveled front wall  28 , which presents an upper hopper opening  29  to allow the contaminated soil (not shown) to be easily dumped within the hopper well  26  for processing.  
         [0063]    In use, the hopper  22  is positioned adjacent to and/or supported by an inclined conveyor designated generally be the reference numeral  30 , the proximal end  41 P of which is in operable relationship with a hopper opening (not shown) in the bottom of the hopper  22 . Inclined conveyor  30  is supported by upright supports  32  attached to the sides  36  of the conveyor and the trailer bed  16  referred to above. Exit chute  34  is directed downwardly and away from the distal end  41 D opposite end  41 P such that soils entering the hopper  22  are carried upward on a conveyor belt (not shown) interpositioned between the sides  36  of the inclined conveyor  30 .  
         [0064]    The conveyor belt is powered by a motor assembly  38  further preferably comprising an electric motor  40  positioned about a conventional roller shaft (not shown) to drive the conveyor belt upwardly from the proximal end  41 P to the distal end  41 D and in alignment with the exit chute  34  which directs the soils from the conveyor  30  into the heating chamber portion designated generally by the reference numeral  44 . A drive axle cover  42  is positioned adjacent one of the sides  36  of the incline conveyor  30  to help minimize the possibility of inadvertent user contact with the components which rotate and turn therebelow.  
         [0065]    The heating chamber portion  44  is further comprised of a burner station  46 , a heating cylinder station  48 , and a soil exit station  86  associated with the soil removal portion of the invention designated generally by the reference numeral  72 .  
         [0066]    The soil removal portion  72  includes an inclined conveyor similar to the one described as conveyor  30  and is designated generally by the reference numeral  74 . The inclined conveyor  74  has a proximal and distal end  75 P and  75 D respectively. Proximal end  75 P is positioned adjacent to the soil exit station  86  of the heating section  44 .  
         [0067]    After the contaminated soils are heated (i.e., processed) within the heating section  44  they are expelled therefrom by rotational migration from the entrance of the heating cylinder station  48  to the exit station  86  and are received by the removal portion  72  near the proximal end  75 P of the inclined conveyor  74 .  
         [0068]    Upright frame supports  76  enable the incline conveyor  74  to be angled upwardly and away from the exit end  45  of the heating chamber section  44 . In addition, cage  78  provides additional means but not total isolation from the exit end  45  because of the high temperatures associated with the processed soils.  
         [0069]    Inclined conveyor  74  further includes spaced-apart sides  80  only one of which is shown in the figure, an ejection port  82  positioned at the distal end  75 D. Processed soil is moved along a conveyor belt (not shown) upwardly and away from the heating exit section  45  and is expelled through the chute  82  onto the ground or into some other user provided receptacle.  
         [0070]    Motor  84  is preferably electric and similar to that designated as motor  40  with respect to the infeed portion  20 . It provides the rotational force to the roller bearing (not shown) sufficient to move the conveyor belt (not shown) and carry the soils. Deflecting baffle  86  may include an optional hinged door (see FIGS. 6A and 6B) enabling the heated soils that exit the heating section  44  to be carried away by the conveyor  74  as described.  
         [0071]    With reference to FIGS. 2A and 2B, burner station  46  includes a vertical cabinet type housing  99  covering a variety of heating components including a heater assembly designated generally by the reference numeral  100 . Heater assembly  100  further includes gas supply line  102  connected to an external supply of flammable gas (e.g., natural gas or propane) but not shown. Supply lines  102  and  106  further includes gas regulator(s)  108  to throttle the flow and pressure of the flammable gas into the burner  100 . The exhaust of the burner is heat which is moved by blower  104  which is positioned opposite the vent assembly  110 . The preferred embodiment of the vent assembly  110  is covered by an insulating blanket  111  enabling the heated exhaust from the burner to be blown into the interior of the heating chamber  124  (FIG. 5) during use.  
         [0072]    With reference to FIGS. 2B, 3A,  3 B,  4  and  5 , the chute  34  is shown having an exit port  112 , a circumferential plate  114 , and an annular collar  115  which surrounds the exit port  112 . The combination of the plate  114  and collar  115  and are sized to correspond to the relative dimensions of the end plate  126  and interior  124  of the heating cylinder  122  of FIG. 5.  
         [0073]    The heating cylinder  122  is operably supported wheels  116  fitted to shafts  118  and held in proper alignment by bearing supports  25 . The bearing supports  25  and the guide rollers  135  of FIGS. 6A and 6B maintain the heating cylinder in proper elevation above the frame  13  and axial position with respect to the exit end ring  130  (FIG. 6B).  
         [0074]    With specific reference to FIGS. 3A and 3B, roller drive motor  127  has a motor shaft  129  fitted with drive sprocket  123 . Chain  121  is laced onto the drive sprocket  123  and interlaced between tension sprockets  125  and cylinder drive sprockets  120 . In use with the heating cylinder  122  having roller bearing surface  131  resting on the cylinder rollers  116  and against the guide rollers  135  (FIG. 8), the motor  127  imparts a rotational torque to the shaft  129  which then rotates the drive sprocket affixed thereto. Chain  121  turns the roller sprockets  120  in the same direction as the chain  121  is interlaced around them. Tensioners  125  take up the slack in the chain and are adjustable to compensate for the stretching of the chain over prolonged use.  
         [0075]    The heating cylinder  122  is made of steel and has an internal chamber  124  and has spiral flutes  128 , an external flanged end plate  126  having optional cutouts  133  or optional proximity peg  135  either of which allows the user to monitor the rotation of the cylinder  122  as properly rotating beneath the cover  146  which is provided to mate in close conjunction with plate  114  of FIG. 3B, 4 and  8 . Blanket  142  is fastened around the exterior surface of the cylinder by band type fasteners  144  which resist high temperatures (e.g., wire, flexible hose clamps, metal banding, etc.). The blanket  142  is made from a high temperature resistant fabric or asbestos material, and is provided to insulate the cylinder from heat loss and improve efficiency.  
         [0076]    In use, when flame is introduced into the interior of the steel cylinder  122  via the burner blower  104  through the vent assembly  110 , the expansion of the steel cylinder  122  takes up the separation distance and space between plates  126  and  114  (FIG. 8) and guide rollers  135  help maintain the proper separation distance despite thermal expansion. The rotation of the cylinder is believed necessary to cause the soils to migrate from one end of the cylinder  122  to the exit end  45  (FIG. 1).  
         [0077]    During operation the interior of the cylinder is approximately one thousand six hundred degrees (1600°) and the temperature of the soil exiting therefrom is approximately nine hundred degrees (900°). These temperature are believed to be adequate to cause the hydrocarbon contaminants associated with contaminated soils to burn and thus render the soil inert. The spiral flutes  128  assist with the migration of the soils.  
         [0078]    With reference to FIGS. 6A and 6B, exit opening  132  further includes angled walls  134  and chute  136 . The optional trap door  138  is operably configured to enable the weight of the heated soil to push it open against its biasing force enabling the soil to fall freely therethrough and be expelled from the cylinder  126 . Chute  136  directs the soils from the cylinder to the exit  132 .  
         [0079]    With reference to FIGS. 9 and 10, a cover or shield component is designated generally by the reference numeral  146 . Cover  146  includes an arcuate body  147  and interior reinforcing ribs  148  to maintain its curved shape and secure the insulation  152  to the interior surface  153  of the cover  146 . The insulating material  152  allows the material to reflect heat inwardly back toward the cylinder blanket therefore helping to maintain the overall efficiency of the operating temperatures established within the cylinder.  
         [0080]    The cover  146  also includes end flanges  151  and side flanges  156  enabling the cover to also serve as a shroud or cowling to further minimize inadvertent contact with the heated surface. Optional hangers  154  are provided as a lifting mechanisms of the cover such that what is potentially cumbersome is now easily managed by a sling arrangement fitted to the hangers  154  positioned at each end (only one of which is shown), to facilitate easy removal thereof.  
         [0081]    These and other embodiments of the present invention shall become apparent after consideration of the scope of the specification, drawings, and claims set forth herein. All such embodiments and equivalents thereof are contemplated to be covered by and within the scope of the claims appended hereto, even though not specifically set forth herein due to the limitation of space.