Abstract:
A method of breaking up a structure for the recovery of steel as scrap. The structure has steel plates forming a compartment secured to framing in the compartment. The method includes at least partially filling the compartment with a substantially incompressible substance and placing explosive in the substance in the compartment. The explosive is sufficient and adapted on detonation thereof to pressurize the compartment to the extent of causing separation of the plates from the framing. The method further includes detonating the explosive.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    This invention relates broadly to scrapping structures having steel components for recovery of the steel as scrap; and more particularly, to a method of scrapping barges having extensive steel plate incorporated therein, for the recovery of the steel as scrap for recycling.  
           [0002]    The invention is primarily concerned with scrapping barges which have outlived their usefulness on the rivers and/or seas. Such barges typically include large quantities of steel which, when salvaged as scrap, represent a valuable commodity. While the invention is herein disclosed as it pertains to the scrapping of barges, it is contemplated that it may be applicable to the scrapping of other structures having floodable compartments and steel plate worthy of salvaging for recycling.  
           [0003]    Typically, barges such as those to be scrapped in accordance with the invention have a bottom, sides extending up from the bottom and ends extending between the sides defining a cargo hold. The sides and ends comprise steel plates welded together on framing. Heretofore, such barges have been scrapped after they have outlived their usefulness on the waterways (i.e., after becoming unserviceable) primarily by cutting off steel plates with a cutting torch and breaking up the cut-off plates into scrap (i.e., small pieces) by means of hydraulic shears. This procedure, although effective, is labor intensive, typically taking as much as several man weeks to complete and thereby increasing the cost of the scrap and reducing profitability.  
         SUMMARY OF THE INVENTION  
         [0004]    Accordingly, among the several objects of this invention may be noted the provision of a method of scrapping a steel structure such as a barge by breaking up the structure for the recovery of steel as scrap which reduces the labor involved in scrapping the structure over that heretofore required, thereby making scrapping more economical; the provision of such a method adapted concurrently to effect reduction of the steel to scrap pieces as well as the break-up; and the provision of such a method using relatively economical components.  
           [0005]    It is contemplated that the method would be applicable to the scrapping of structures other than steel barges which have steel plates forming a floodable compartment secured to framing in the compartment. The method involves breaking up the structure for the recovery of steel as scrap by at least partially filling the compartment with a substantially incompressible substance and placing explosive in the substance in the compartment. The explosive is sufficient and adapted on detonation thereof to pressurize the compartment to the extent of causing separation of the plates from the framing. The method further includes detonating the explosive.  
           [0006]    Other objects and features will be in part apparent and in part pointed out hereinafter. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0007]    [0007]FIG. 1 is a plan of a barge of a type subject to scrapping for steel using the method of the present invention;  
         [0008]    [0008]FIG. 2 is a side elevation of the barge partially broken away;  
         [0009]    [0009]FIG. 3 is an end elevation of the barge;  
         [0010]    [0010]FIG. 4 is a section through the barge taken in the plane of line  4 - 4  of FIG. 1;  
         [0011]    [0011]FIG. 5 is a section taken in the plane of line  55  of FIG. 1;  
         [0012]    [0012]FIG. 6 is a section taken in the plane of line  66  of FIG. 1;  
         [0013]    [0013]FIG. 7 is a detail of the section of FIG. 5; and  
         [0014]    [0014]FIG. 8 is a perspective of a plate weakened for scrapping in accordance with the present invention. 
     
    
       [0015]    Corresponding reference characters indicate corresponding parts throughout the several views of the drawings.  
       DETAILED DESCRIPTION  
       [0016]    Referring to the drawings and first to FIGS.  1 - 6 , a conventional barge made principally of steel to be scrapped in accordance with the present invention is designated in its entirety by the reference numeral  1 . The barge  1  is essentially rectangular in plan comprising an essentially rectangular bottom  3 . Sides  5 ,  7  and ends  9 ,  11  extend upward from the bottom  3  to define an essentially rectangular cargo hold  13 . Either end  9 ,  11  may be the forward end and the other the aft end. The barge may, for example, be on the order of about two hundred feet long (in overall length) and about thirty-five feet wide, thereby incorporating a substantial amount of steel subject to salvage as scrap.  
         [0017]    The bottom  3  is typically of double construction comprising a steel cargo hold floor  15  mounted on transverse steel stringers  17  on a flat steel outer hull  19 . The floor  15  and hull  19  comprise steel plates having their edges welded to adjoining plates and to the stringers  17 . The sides  5 ,  7  are essentially identical to each other. Each of the sides  5 ,  7  is of double-walled construction comprising two spaced walls, an inner wall designated in its entirety by the reference numeral  21  and an outer wall designated in its entirety by the reference numeral  23 . The walls  21 ,  23  extend upward generally vertically from the periphery of the bottom  3 . Each of the walls  21 ,  23  comprises a plurality of steel plates  25  secured by welding to adjoining plates and to internal steel framing indicated generally at  27  including partitions or bulkheads  29  also of steel plate dividing the space between the walls into compartments  31 . Each side  5 ,  7  has a top  33  comprising steel plates surmounted by a steel coaming  35  which surrounds a top of the cargo hold  13 . The barge ends  9 ,  11  are substantially identical to each other. In an alternate embodiment (not shown), the barge ends may differ from each other. Each of the ends  9 ,  11  is of double-walled construction comprising two spaced walls, an inner wall designated in its entirety by the reference numeral  37  and an outer wall designated in its entirety by the reference numeral  39 . These end walls  37 ,  39  extend up from the periphery of the bottom  3 . Each of the end walls  37 ,  39  comprises a plurality of steel plates  41  secured by welding to adjoining plates and to internal framing indicated generally at  43 . Each of the ends  9 ,  11  has steel plate sides  45  and a top  47  which with the bottom  3  and walls  37 ,  39  form a floodable compartment  49 .  
         [0018]    To scrap a barge such as described above, the barge is hauled out of the water, and then broken up by the method of this invention for the recovery of its steel as scrap. As illustrated in FIG. 7, holes such as indicated at  51  are cut in the top  33  of each side  5 ,  7  of the barge providing access to each of the compartments  31  and in the top  47  of each end  9 ,  11  of the barge providing access to each of the compartments  49 . Each compartment  31 ,  49  is at least partially filled with a substantially incompressible substance such as water W through one or more of the holes  51 . The compartments may be filled with other incompressible substances such as sand or mud instead of or in addition to the water. Conventional explosive charges  53  are placed in the water W in each compartment  31 ,  49 . Each charge  53  has a conventional detonator (not illustrated) for detonating the explosive. As shown in FIG. 7, in one embodiment the charges  53  are suspended in the water W in the compartments  31 ,  49  through the holes  51  by rope, cables, wood or polymeric pipe  55 . Conventional non-electric detonators (not shown) are connected to the charges  53  prior to being lowered into the compartments  31 ,  49 . Although the charges  53  may be suspended at other heights within the compartments  31 ,  49  without departing from the scope of the present invention, in one embodiment the charges are suspended about halfway between the top and bottom of the compartments. After the charges  53  are inserted through the holes  51  and suspended in the compartments  31 ,  49 , the holes  51  are covered such as with sandbags  57 . The charges  53  in each compartment  31 ,  49  are capable of such explosive force on detonation thereof as to pressurize the water in the compartment to the extent of causing separation of the plates  25 ,  41  from the internal framing  27 ,  43 . More preferably, the charges  53  are capable of causing the separation of the plates  25 ,  41  at the welds which secured them to the internal framing  27 ,  43  and to each other.  
         [0019]    After the explosive charges  53  are placed in the water W in the compartments  31  and the holes  51  are covered, the charges are detonated, causing pressurization of the water in the compartments  31 ,  49  with resultant separation of plates  25 ,  41  from the internal framing  27 ,  43  (including the bulkheads  29 ) and separation from one another, separation occurring primarily at the welds which secured the plates to the internal framing and which secured them together. The separated plates may then be folded or cut up into scrap by hydraulic shears.  
         [0020]    The explosive charges  53  may be all detonated simultaneously or may be detonated at intervals such as one-quarter second intervals one after another. Although the holes  51  (and therefore the charges  53 ) may be spaced at other intervals without departing from the scope of the present invention, in one embodiment the holes are spaced at three to five foot intervals along the sides  5 ,  7  and ends  9 ,  11  of the barge  1 . The holes  51  may be on the order of three inches in diameter. Although other amounts and kinds of explosive may be used, in one embodiment each explosive charge  53  is a charge of dynamite in an amount between about 0.05 pound per ton of water W in the respective compartment  31 ,  49  to about 0.8 pound per ton of water in the respective compartment. Preferably, the explosive charge  53  is a non-dead-pressing explosive. Further, it is desirable that the charge  53  have a negative buoyancy.  
         [0021]    As will be appreciated by those skilled in the art, the amount of explosive needed is inversely proportionate to the depth of the water W in the compartment  31 ,  49 . Because some compartments leak, they cannot be easily filled entirely with water W. More explosive is needed in the compartments which cannot be filled with water. For example, if the compartments  31 ,  49  are filled ten feet deep with water, it may only be necessary to use eight pounds of dynamite spaced at five foot intervals around the barge  1 . However, if the compartments  31 ,  49  can only be filled five feet deep with water, it is envisioned a greater amount of dynamite (e.g., 11 pounds spaced at five foot intervals) may be needed.  
         [0022]    In certain instances, the need for cutting up the broken-off plates  25 ,  41  with hydraulic shears may be eliminated by weakening the plates  25 ,  41  beforehand so that they will be broken up into pieces on detonation of the explosive. This weakening may, for example, be by scoring the plates  25  on the barge in a grid pattern such as shown in FIG. 8, the scores being indicated at  57 . Scoring may be carried out by using a grinder, for example. Alternatively, it is envisioned that the weakening may be accomplished by strategically cutting or notching or embrittling the plates  25 ,  41  and framing  27 ,  43  in an appropriate pattern. It is envisioned that a conventional torch may be used to create a heat affected zone to embrittle the plates thereby to weaken them.  
         [0023]    It is noteworthy that, even though the blasting may be carried out in a populated area, the sound of the blasting is deadened, being muffled by the water W. Also, the plates come loose, and/or break up into pieces, without any particular danger from steel flying around.  
         [0024]    Using the method of the present invention, the preparation for blasting, the blasting and subsequent work requires much fewer man-hours than previous methods.  
         [0025]    In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.  
         [0026]    As various changes could be made in the above methods without departing from the scope of the invention, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.  
         [0027]    When introducing elements of the present invention or the preferred embodiment(s) thereof, the articles “a”, “an”, “the” and “said” are intended to mean that there are one or more of the elements. The terms “comprising”, “including” and “having” are intended to be inclusive and mean that there may be additional elements other than the listed elements.  
         [0028]    In view of the above, it will be seen that the several objects of the invention are achieved and other advantageous results attained.