Abstract:
An incinerator, capable of withstanding internal shocks from projectiles resulting from the combustion of energetic materials, is made of a primary combustion chamber where the material is burned, and a secondary chamber to reburn at a higher temperature the gases emanating from the primary chamber. The incinerator has a heating or separation plate, having a flowing-material funnel facilitating the removal of waste solids, to provide heat exchange between the primary combustion chamber and a heating chamber, to protect the heating elements against projectiles, and to restrain any projectiles from exiting the unit. To increase the level of safety of operation, this incinerator is remotely controlled, has a sequence of ignition and has overpressure apertures over the primary chamber.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims the benefit of U.S. Provisional Application No. 60/318,823 filed Sep. 14, 2001, incorporated by reference herein. 
    
    
     FIELD OF THE INVENTION 
     This invention relates to an incinerator, and more particularly to an incinerator which provides safe operation and efficient disposal of hazardous, explosive or illicit materials and which can withstand internal shocks. 
     BACKGROUND OF THE INVENTION 
     Disposal of hazardous, explosive or illicit materials requires a unit which can be displaced in order to burn the material at a site or near a site where the material is stacked. This alleviates hazards and costs related to transporting the material off site. 
     In the past, it was common to dig a pit, place the contraband in the pit, pour accelerant over the material and burn it. This method has been deemed totally unacceptable as it generates unrestrained noise and pollution from known pollutants, such as lead, antimony, potassium nitrate, sodium nitrate and sulfur. There is also a threat of various unknown pollutants due to the diversity of material that can be processed, including various heavy metals and organic chemicals, such as nitrocellulose, nitroglycerine and DBP (plasticizer). 
     Another known method of burning ammunition makes use of an open drum that contains two trays with fissures. In the bottom tray, fuel in the form of fuel oil and wood shavings are added, and the ammunition is added to the top tray. During the burning process, part of the low boiling metals are melted and fall through the tray fissures and into the drum bottom. Due to the explosive nature of the material, pollutants are emitted into the air and eventually fall to the ground. 
     An ammunition incinerator, known as the “Hurd” burner from the Hurd&#39;s Custom Machinery Inc. has a reinforced body, defining a single combustion chamber, in the shape of a fuel tank. The burner fires directly in the combustion chamber and there is no reburn system. This unit generates a lot of smoke, which contains noxious gases from the ammunition. Also the manual ignition of this device leaves too much room for error, causing structural damage at the door and being hazardous for the operator. 
     U.S. Pat. No. 5,727,481, issued on Mar. 17, 1998 discloses a mobile armored incinerator for similar uses, which provides pressure release hatches and a reburn system, but the latter is not integrally built in the body. The burners fire directly in the primary chamber and there are air intakes in direct communication with the primary chamber. This leaves many exposed parts which may be hit by projectiles, or gaps from which projectiles can escape. Also, the loading cart does not provide material separation. 
     In general, incinerators are designed to be used with regular refuse material. Typically, their internal walls are made of refractory material, and they do not include armored panels nor overpressure hatches to cushion possible sudden blows. 
     Therefore there is a need for an incinerator which alleviates some of the disadvantages of the prior art. 
     SUMMARY OF THE INVENTION 
     This invention relates to an incinerator capable of withstanding internal shocks resulting from the combustion of the material to be burned. 
     Thus, according to one aspect, the invention provides an incinerator capable of withstanding internal shocks resulting from combustion of material to be burned, the incinerator comprising a body including a primary combustion chamber for burning the material, a heating chamber for providing heat to the combustion chamber, and a bullet proof separation plate providing separation between the primary combustion chamber and the heating chamber to prevent projectiles from escaping, and providing sufficient heat exchange between the primary combustion chamber and the heating chamber. 
     There are many advantages in using an incinerator according to the invention. First, by containing projectiles emitted during the combustion process, and therefore various pollutants, that are propelled into the air, contact of the pollutants with the ground is eliminated, which in turn controls the environmental impact on soil, water and air. Also, by burning at high temperatures, combustion efficiency is improved and the levels of emitted pollutants to the air may be decreased. 
     Other aspects and advantages of embodiments of the invention will be readily apparent to those ordinarily skilled in the art upon a review of the following description. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Embodiments of the invention will now be described in conjunction with the accompanying drawings, wherein: 
     FIG. 1 is a front perspective view of the incinerator in accordance with this invention with the door opened to show some interior elements; 
     FIG. 2 is a front view of the incinerator of FIG. 1 with the door removed to show constructional details; 
     FIG. 3 is a side view of the incinerator showing constructional details and a schematic of the gas circuit; and 
     FIG. 4 is a front view of the incinerator with the door closed. 
    
    
     This invention will now be described in detail with respect to certain specific representative embodiments thereof, the materials, apparatus and process steps being understood as examples that are intended to be illustrative only. In particular, the invention is not intended to be limited to the methods, materials, conditions, process parameters, apparatus and the like specifically recited herein. 
     DETAILED DESCRIPTION OF THE INVENTION 
     Referring to FIG. 1, there is illustrated an armored incinerator  10 , having a generally cylindrical body  60 , closed at one end and open at the other end. The open end is adapted to be closed by a door  50 . The body  60  includes a primary combustion chamber  15 , and a heating chamber  20  having first heating means  105 . 
     The primary combustion chamber  15  includes a support means, preferably in the form of a loading tray  25 , where the material to be burned is fed. There are also air intakes  175  (seen in FIG. 2) to allow ambient air to pass into the primary combustion chamber via the heating chamber. A secondary combustion chamber  40  is located in an upper portion of the primary chamber  15  and has a second heating means  120  (seen in FIG.  3 ), and an exhaust vent  45 . A heating plate, or separation plate,  30  separates the primary combustion chamber  15  from the heating chamber  20 . The heating plate  30  serves to provide a heat exchanging means between the heating chamber  20  and the primary combustion chamber  15 , and to distribute the heat evenly from the heating chamber  20  in the primary combustion chamber  15 . Plate  30  also prevents projectiles, which result from the combustion, from escaping the primary combustion chamber  15  via the air intakes  175 . 
     The first heating means  105  is in the form of heating elements in communication with external primary gas burners  100  (seen in FIG.  3 ). The second heating means  120  is in the form of external gas burner in communication with the secondary combustion chamber  40 . Propane gas or natural gas can be used interchangeably, either from a gas tank  160  or directly from a source line. Electrical means can be used instead of gas burner without departing from the scope of the invention. 
     Referring to FIGS. 1 and 3, the body  60  of the incinerator unit comprises several panels  66  to  73  welded, or secured by expansion joints, to form a polygon in cross-section. It will be appreciated that the incinerator can be of various proportions and sizes to be adapted to different situations. In one embodiment, these panels form an octagon, however other shapes such as hexagon, heptagon or dodecagon can be used without departing from the invention. Two of these panels  66 ,  70  are vertically disposed to form opposite sides of the body  60 . These panels are welded, or otherwise fastened, to the extensions  81 ,  82  of the frame. The two upper corner panels  67 ,  69  adjacent and disposed over the vertical panels  66 ,  70  converge to either the next panel  68  (to form an octagon), to the next panels (to form a decagon, not shown), or to a common joint (to form a hexagon or heptagon, not shown). 
     The upper corner panels  67 ,  69  each have a pressure control means to control the pressure in the primary combustion chamber  15 , comprising overpressure apertures  74 ,  75  each covered by a hinged panel  64 ,  65 . The hinged panels  64 ,  65  have hinge means  61 ,  62  on one side, and can sit by gravity over their respective upper corner panels  67 ,  69  or have means to remove or add some weight to the hinged panel depending on the side and weight of the latter. This is dependent upon the pressure limit which is considered as unsafe operation. In this embodiment, the right hinged panel  64  is shown in a closed position, and the left hinged panel  65  is shown in an open position. Steel or other high impact material screen  76 ,  77  covers the inside of the overpressure apertures  74 ,  75  to prevent projectiles to escape the unit in the event that the overpressure panels  64 ,  65  have to open in operation. 
     Tray supports  27  and plate supports  36 , each inside the vertical panels  66 ,  70  removably retain respectively, the loading tray  25  and the heating plate  30 . These supports  27 ,  36  can be an integral part of the vertical panels  66 ,  70 , or can be a separate element welded, or otherwise fastened, to the vertical panels  66 ,  70 . The loading tray  25  has perforations to permit the material in fusion or in sub-fluidic state to flow through or pass through these perforations and to fall on the heating plate  30 . The loading tray  25  also has lips  26  which cooperate with the tray supports  27 , to allow the loading tray to be removable. Generally, the loading tray  25  slides in and out of the unit, with the material to be burned disposed upon the loading tray  25 . 
     A second tray  28  (seen in FIG. 4) is also supported in the bottom part of the frame, by sliding over supports  29  (seen in FIG.  4 ). Tray  28  can be used for a second load of material to be processed. Generally, tray  28  is removed from the incinerator while the material in tray  25  is being combusted, so that resulting debris may fall from heating plate  30 . Also, when a burn has just finished, it is possible to use these supports  29  to let the tray  25 , coming from the primary combustion chamber  40 , cool down before any other manipulation. 
     The heating plate  30  is curved or sloped, from the front view, to force the material having passed through the loading tray  25 , usually the material having lower fusion temperature, to a central funnel portion  31  in the heating plate  30 . The heating plate  30  is also curved or sloped, perpendicularly from the front view, to force the same material to converge to this funnel portion  31 . The funnel portion  31  is in communication with a passage  32  adjacent to, and heated by, the first heating means  105  so that the material is in a flowable state. The material flows out of the body  60 , by an aperture  33  in the bottom plate  72 , to a collecting bin  34  under the unit. The bin  34  can be of various designs, from a single use bin to a mold to form ingots. The other part of the burned material (usually of higher fusion temperature and bigger dimension) remains on the loading tray  25 , which is removed after a burn to be cleaned for the next batch. 
     A box  41  insulates the primary combustion chamber  15  from the secondary combustion chamber  40 . This box  41  can be formed by a panel (for hexagonal or heptagonal units, not shown), or panels  42  (for octagonal or decagonal units), and the top panels of the body (for hexagonal or heptagonal units, not shown), or the top panel  68  of the body (for octagonal or decagonal units). The box  41  is closed at the front end by a panel  43  and opened at the back end to permit the flow of the gases exiting or emanating from the primary combustion chamber into the secondary combustion chamber  40 , where the exhaust gases are burned off at a higher temperature and for the passage of the secondary burning element  120  (seen in FIG.  3 ). Exhaust gas from the secondary combustion chamber  40  exits through an aperture in the top panel  68  (for octagonal or decagonal units) or at the intersection of the top panels (for hexagonal or heptagonal units), adjacent to the front end of the box, through the exhaust vent  45 , such as a catalytic converter or a simple chimney. 
     All the internal walls of the primary combustion chamber  15  can be covered by stainless steels sheets or with any other heat resistant material capable of withstanding high impact. These sheets may be applied inside the top part of the vertical panels  66 ,  70 , of the upper corner panels  67 ,  69 , the top panel  68  and the hinged panels  64 , 65 . In this way, the material of the panels  64  to  73  of the body  60  can resist penetration by most projectiles. The outside walls of the secondary combustion chamber  40  may be insulated on the inside in order to retain the heat during operation. 
     Referring to FIGS. 1 and 3, the first heating means  105  of the primary combustion chamber  15  are fed from the gas burners  100  (typically, one on each side). A local control manifold  150  regulates the flow of gas, from the information given by the user via a remote control unit  155  and from temperature sensors, such as thermocouples  125 ,  130 ,  135 . The local control manifold  150  incorporates the necessary control valves and regulators (not shown) disposed according rules and standards of gas installations as known in the art. From this circuitry, the gas burners  100  and the secondary gas burning element  120  are fed with gas using gas lines  101 ,  121  respectively. Thermocouples  125 ,  130 ,  135  are disposed in some or all the chambers to detect undesirable temperature variations, these thermocouples are linked to the local control manifold  150  by heat resistant electrical cables  126 ,  131 ,  136 , respectively. Control means (not shown) in the local control manifold  150  regulates the flow of gas from signals received from the thermocouples  125 ,  130 ,  135  and from other sensors which can be also incorporated to detect other parameters, such as pressure, presence of specific gas, velocity of gases, etc. 
     With the local control manifold  150  and the remote control unit  155 , the operator can start/ignite or stop the incinerator from a safe distance. Also by having a simple means for ignition the operator can pay more attention to the surrounding of the unit to detect any sign of hazard. 
     The incinerator can be mounted on extensions  81 ,  82  of a supporting frame  80  on each side of the body, to be supported by the leg parts  83 ,  84 , and then be transported from site to site by hoisting the unit by the frame elements on each side of the body, for example frame elements  85 . Also, any part of the frame  81  to  87  can be secured, fastened or welded to a structure, such as a trailer, a sleigh, a barge, or even to a fixed structure, if needed. These installations will have to be done according to applicable safety standards and leaving enough room around the unit for heat dissipation. 
     Referring now to FIG. 4, the front end of the body  60  is closed during operation of the incinerator by a door  50 , which can also preferably, totally cover the top part of the frame. One solution to obtain a blast resistant door is to have reinforcement bars  51  over the door having extensions  53  on each side. These extensions  53  cooperate with similar extensions  52  (seen in FIG. 1) on each side  81  of the frame. 
     The door may include hinges on one side for improved strength. Also, an electric shut-off (not shown) may be included as a safety measure to shut off the propane in the event that the door opens. 
     Also, there may be included a fan and airduct (not shown) mounted to the incinerator and cooperating with the heating chamber. The fan may be remotely operated by remote control unit  97  to speed up the cooling process of the incinerator after the burning process. This will allow the next load of material to be loaded up and burned sooner. 
     Numerous modifications may be made without departing from the spirit and scope of the invention as defined in the appended claims.