Abstract:
An inflatable modularly constructed for use over cites near welding or other operations upon, for example, one or more conduit members, in order to retain within the interior structure unwanted gases, flake, slags, sparks and other debris. The modules may be shaped and provided in such numbers as to provide a specific contour with each member being re-usable in combination with other members for subsequent operations. The modular members are selectively secured together so as to be substantially air tight to provide effective inflation of the unit. A framework may also be provided to assist in enhancing effective inflation during work operations. Fans and filter units may be provided for continuous inflation and to filter the intake inflation gas.

Description:
[0001]    An inflatable modularly constructed unit is provided for use over cites near welding or other operations upon, for example, one or more conduit members, in order to retain within the interior structure or in order to retain exterior of the structure unwanted gases, flake, slags, sparks and other debris created during an outdoor welding process. The modules may be shaped and provided in such numbers as to provide a specific contour during the welding operation, with each member of the unit being re-usable in combination with other shaped and numbered members for subsequent operations. The modular members are selectively secured together one to another by so as to be substantially air tight to provide effective inflation of the unit. A framework may also be provided to assist in enhancing effective inflation of the unit during work operations. Fans and filter units may also be provided for continuous inflation of the unit and to filter the intake inflation gas, such as air, and/or the discharge gas. 
       BACKGROUND OF THE INVENTION 
       [0002]    1. Field of the Invention 
         [0003]    The invention relates to a welding enclosure for use in welding or other operations upon, for example, one or more conduit members, such as those on a well head, oil or gas pipeline, or the like. 
         [0004]    2. Brief Description of the Prior Art 
         [0005]    Subsequent to the drilling of a subterranean oil or gas well, whether such well be located inland, or on a well platform, drill ship, semi-submersible, or the like, the well is completed by introduction of a tubular conduit which is often time referred to as “casing”. The casing is cemented in place as part of the completion operation. Prior or subsequent to the introduction of one or more sections of casing conduit forming the casing string into the subterranean well, it may be necessary or desirable to perform a welding or other operation to one or more ends of the casing to affix, for example, a blowout preventer, or other component desirable to be fixedly secured to the casing conduit section. In many instances, such component will be affixed to such casing conduit member by welding operations well known to those in the industry. As a result of the flame discharge from the welding torch, during the welding operation, or other common operations, sparks, slag and other debris can be expected to be discharged into the air around the welding or other operation resulting in a serious fire hazard during the welding operation. Such slag and sparks could touch off a fire or even worse, an explosion, since the casing often times will be introduced into a “live” well which, at any time, could become uncontrollable as a result of a leak or blowout of flammable fluids, such as natural gas, or the like. 
         [0006]    Because many such welding or other associated operations are conducted at very remote locations, such as in jungles, offshore, in desert environments, islands, forests, figid locations, and other hostile environments where transportation is not convenient and weight and size of transported materials is at a premium, it would be desirable to provide materials used in such operations that are light weight in construction, can be reused, and transported in a manner that eliminates wasted and unnecessary cargo space. Furthermore, the geometric configuration of a needed welding enclosure may be expected to vary from one location to another, in size as well as in shape, such that what is satisfactory for one location and operation would be considered disadvantageous for another particular location. 
         [0007]    The present invention addresses the problems as set forth above. The relevant prior art of which applicant is aware is as reflected in the following U.S. patents: 
         [0008]    U.S. Pat. No. 5,101,604, entitled “Subterranean Welding Habitat”. 
         [0009]    U.S. Pat. No. 5,018,321, entitled “Subterranean Welding Habitat”. 
         [0010]    U.S. Pat. No. 2,872,933, entitled “Air-drilling Rig Cover”. 
         [0011]    U.S. Pat. No. 3,308,266, entitled “Method and Apparatus for Welding of Rails”. 
         [0012]    U.S. Pat. No. 3,837,171, entitled “Inflatable Underwater Structure”. 
         [0013]    U.S. Pat. No. 3,946,571, entitled “Service Module for Environment”. 
         [0014]    U.S. Pat. No. 3,991,583, entitled “Method of Providing an Underwater Enclosure”. 
         [0015]    U.S. Pat. No. 4,257,720, entitled “Apparatus and Method for Driving Members Into the Ocean Floor”. 
         [0016]    The following patents also are known to applicant and are of general interest: 
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 U.S. Patents. 
               
             
          
           
               
                 Patent No: 
                 Issue date: 
                 Inventor: 
               
               
                   
               
               
                 2872933 
                 February 1959 
                 Mackey 
               
               
                 3250024 
                 May 1966 
                 Douthitt et al. 
               
               
                 3335529 
                 August 1967 
                 Gedney 
               
               
                 3452764 
                 July 1969 
                 Bell 
               
               
                 3525290 
                 August 1970 
                 Pelsue 
               
               
                 3626836 
                 December 1971 
                 Schneidler 
               
               
                 3783906 
                 January 1974 
                 Matherne 
               
               
                 3946571 
                 March 1976 
                 Pate et al. 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 Foreign Patent Documents 
               
             
          
           
               
                 Patent No: 
                 Issue date: 
                 Inventor: 
               
               
                   
               
               
                 681345 
                 September, 1939 
                 DE2 
               
               
                 2135965  
                 February, 1973 
                 DE 
               
               
                 497787 
                 December, 1938 
                 GB 
               
               
                   
               
             
          
         
       
     
       SUMMARY OF THE INVENTION 
       [0017]    A modular welding or other operations enclosure unit has an exterior and an interior, for entrapment of welding slag, sparks, and the like within said interior during welding along at least one fluid conduit member forming a fluid transmission line. As used herein, “conduit member” or “conduit” means any surface upon which a heat or other operation, such as welding, is to be conducted, and wherein such operation results in the creation or use of gases, slag, dust, sparks, and similar resultant materials, which are desired to be contained within a controlled environment during the heating operation. Such “conduits” include surfaces on blow out preventers, oil and gas transmission lines, and the like. 
         [0018]    A plurality of selectively joinable and selectively separable inflatable members are provided which, when joined, form a modular unit mounted over a point along the conduit member and upon which a welding or heating procedure is to be conducted. Means on each of the inflatable members are also provided for selectively joining to and selectively separating from said inflatable members at least another of said inflatable members whereby, when joined to one another and when positioned over the conduit member, the inflatable members may be inflated and retained inflated to form the modular unit during welding on the conduit member. 
         [0019]    The device of the present invention may be used to also prevent debris, such as sparks, and the like, from entering within the interior of the device while an “operation”, such as welding, or the like, is being conducted exterior of the device, on an offshore platform, or any other location, such as a refinery, chemical plant, or the like. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0020]      FIG. 1  is a perspective view of the present modular unit shown in inflated position over a conduit work area. 
           [0021]      FIG. 2  is a view similar to that in  FIG. 1 , but taken interiorally during a welding operation. 
           [0022]      FIG. 3  is an exterior view of an embodiment having a dome-like configuration with an exterior support frame. 
           [0023]      FIG. 4A  is a view of an embodiment of the present invention illustrating a modular pyramid-like geometric configuration of inflatable members. 
           [0024]      FIGS. 4B and 4C  are views of a selectively collapsible internal support frame structure for the pyramid-like geometric configuration modular unit shown in  FIG. 4A . 
           [0025]      FIG. 5  is an exterior view of a preferred embodiment of the present invention in perspective with incorporation of an exterior support frame. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0026]    Now with first reference to  FIG. 1 , there is shown the modular unit  10  in inflated position over a conduit, such as a well head W of an oil or gas subterranean well ( FIG. 2 ). The unit  10  is composed of a series of separate module or inflatable members,  10 A- 10 M, which are secured one to another prior to inflation by means of companion VELCRO strips  11  secured around the outer edges pf each inflatable member. An air lock  12  is provided with an opening  12 A ( FIG. 2 ) through which a worker P ( FIG. 2 ) may enter and exit. The air lock has a flap member  12 B thereon which may be opened or closed both interiorally and exteriorally after the worker P has passed through it, to maintain inflation integrity during the welding operation. 
         [0027]    It will be appreciated that the inflation members  10 A-M forming the unit  10  do not have to be absolutely air tight at the interface of the VELCRO strips  11 , and only have to assure that the unit  10  may be inflated and maintained in inflated position during the welding or heating operation therewithin. High volume electric fans  13 A and  13 B are provided, with one of the fans being an intake fan, such as  13 A, and the other fan being an exhaust or discharge fan  13 B are provided, preferable at opposite ends of the unit  10 , for introduction of a gas, such as air, or any other inert gas, such as nitrogen, or the like, into and throughout the unit  10  to inflate it and maintain it in inflated position over the selected work area. 
         [0028]    The modular inflation members  10 A-M are preferable made of material that is comparatively light in weight as well as fire resistant or fire retardant, in order to assure that high temperature sparks are retained within the interior of the unit  10  and do not penetrate through the fabric, forming holes. 
         [0029]    The inflatable body  10  may be made of a material comprising a member selected from the class consisting of: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0030]    In Nomex the aromatic groups are all linked into the backbone chain through the 1 and 3 positions. This is called meta-linkage. 
         [0031]    Such a material is commercially available from the DuPont Chemical Company and is sold under the trademark NOMEX. In this product, the aromatic groups are all linked into the backbone chain through the 1 and 3 positions. This is typically referred to as meta-linkage. NOMEX is the registered brand name of a flame retardant meta-aramid material marketed and first discovered by DuPont in the 1970s. It can be considered an aromatic “nylon”. It is sold in both fiber and sheet forms and is used as a fabric wherever resistance from heat and flame is required. Nomex sheet is actually a calendared paper and made in a similar fashion. The paper is used in electrical laminates such as circuit boards and transformer cores as well as fireproof honeycomb structures were it is saturated with a phenolic resin. Both the firefighting and vehicle racing industries use NOMEX to create clothing and equipment that can stand up to intense heat. It is the meta variant of the para-aramid Kevlar. Both aramids are heat and flame resistant but Kevlar, having a para-orientation can be molecularly aligned and gives high strength. Meta aramid polymer cannot align during filament formation and has poor strength. 
         [0032]    Plastics are moldable chemically-fabricated (synthetic) materials derived mostly from fossil fuels, such as oil, coal or natural gas. The long molecules in plastics are composed of carbon atoms linked into chains. One type of plastic, polyethylene, is composed of extremely long molecules, each containing over 200,000 carbon atoms. These long molecule chains give plastics unique properties and distinguish plastics from material such as metal that have crystalline structures. Fossil fuels contain hydrocarbons, which provide the building blocks for long polymer molecules. The building blocks called monomers link together to form long carbon chains called polymers. The process of forming these long molecules from hydrocarbons is called polymerization. The molecules typically form viscous sticky substances known as resins which are the materials used to make plastic products or articles by heating the resins to their specific melting range and molding them into articles by various methods. 
         [0033]    The carbon backbone of polymer molecules often bond with smaller side chains consisting of other elements, including chlorine, fluorine, nitrogen and silicon, for example. These side chains give plastics distinguishing characteristics. For example, when chlorine atoms substitute for hydrogen atoms along the carbon chain, the result is polyvinyl chloride, one of the most versatile and widely used plastics in the world. 
         [0034]    The addition of chlorine makes the plastic harder and more resistant. The advantages and disadvantages of different plastics are associated with the unique chemistry of each plastic which determines the physical, mechanical and thermal properties of the molded article. 
         [0035]    Examples of commonly used thermoplastics which may be sued in forming the body  10  are: polyethylene (PE), polyvinyl chloride (PVC), polypropylene (PP), polystyrene (PS), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), polymethyl methacrylate (PMMA), polyamide (PA) and polycarbonate (PC). In addition, many variations and hybrid engineered resins based on these are in use today. 
         [0036]    Many different processes can be used to make products from thermoplastics for use as the body  10  herein. Some of the more common of these processes are injection molding, extrusion molding, blow molding, injection blow molding, blow film extrusion, calendaring, thermoforming, casting and expansion processes. In all these processes, the plastic must be softened or sufficiently liquefied in order to allow the resin to flow and create the shape of the article. For convenience, all these plastic resin forming processes will be simply referred to as “molding process” hereinafter. 
         [0037]    The inflatable members  10 A-M, etc. are preferably made of fire resistant or fire retardant textile materials. Outer textile materials for fire fighting clothing are useful for the formation of the members  10 A-M. Such materials have previously been manufactured from 100% meta-aramid or polyamideimide blends of meta-aramid and para-aramid fibres or by use of core spun yarns or staple mixtures with polyparaphenylene terephthalamide copolymer or fibres comprising para-aramid cores with meta-aramid or polyamideimide covers. The combination of these fibres in the fabric enhances the non-break open protection of the product. However meta-aramid and polyamideimide fibres shrink, consolidate and thicken when exposed to a high temperature beat source. The presence of para-aramid or polyphenylene terephthalamide copolymer in either the fibre blend or as a core can be used to prevent fibre shrinkage and consequent breaking open of the garment. However the inclusion of para-aramid fibre in the blend has been found to be insufficient in tightly woven fabrics to prevent breaking open and does not increase the air gap between the wearer and the heat source. Consequently there is a need for improved textile materials for manufacture of fire fighting garments and the like. 
         [0038]    Fire fighting garments, which may be used in the manufacture of the inflatable members  10 A-M have been made from a plurality of textile layers, including an outer layer of woven meta-aramid fibre, for example as manufactured under the trademark Nomex as previously stated. Break open protection may be afforded by blending with para-aramid fibres, e.g. as manufactured under the trademark Kevlar and as disclosed in U.S. Pat. No. 3,063,966 and U.S. Pat. No. 3,506,990. 
         [0039]    PCT/GB00/01449 discloses a fire resistant textile material comprising a woven face fabric composed of fibres selected from meta-aramid, polyamideimide and mixtures thereof, the fabric including a woven mesh of low thermal shrinkage fibres. Also useful for incorporation into the members  10 A-M is a woven faced fabric composed of face fibres selected from meta-aramid, polyamideimide and mixtures thereof the fabric including a woven back of low thermal shrinkage fibres, wherein the overfeed of the lower thermal shrinkage fibres is selected so that the sum of the extension under load and take-up is approximately equal to the extension under load and take-up of the face fibres. Such product is known as Kevlar®. This product is a polyamide, in which all the amide groups are separated by para-phenylene groups, that is, the amide groups attach to the phenyl rings opposite to each other, at carbons 1 and 4. Kevlar® is shown as follows: 
         [0000]    
       
                 
         
             
             
         
       
     
         [0040]    In Kevlar the aromatic groups are all linked into the backbone chain through the 1 and 4 positions. This is called para-linkage. 
         [0041]    Novex® on the other hand, has meta-phenylene groups, that is, the amide groups are attached on the phenyl ring at the 1 and 3 positions. 
         [0000]    
       
                 
         
             
             
         
       
     
         [0042]    In Nomex the aromatic groups are all linked into the backbone chain through 1 and 3 positions. This is called meta-linkage. 
         [0043]    Around the edges of each of the modular inflatable members  10 A-J is sewn or otherwise secured hook and loop closure components, sometimes referred to as VELCRO, or the like. Alternatively, snaps, buttons, zippers, ties, eye-hooks, hooks with mating means, etc or the like could easily be integrated or sewn, stitched, glued, grommeted, etc in such a way that they provide the same or similar buckling/closure means for each of the modular inflatable members  10 A-M. 
         [0044]    The modular inflatable members  10 A-M may be provided in any of a number of sizes and geometrical configurations. For example,  FIG. 3  illustrates the unit  10  formed of modular inflatable members  10 A, etc. such that the entire unit  10  takes the shape of a dome-like structure. Similarly,  FIG. 4A  illustrates a pyramid-like configuration that might be built when using inflatable members  10 A, etc. in the geometric configuration shown therein. 
         [0045]    With continued reference to  FIG. 1 , the unit  10  also includes electric or other power driven intake and exhaust fans  13 A and  13 B, secured to the inflatable unit  10  at opposite ends thereof through connecting conduit members  11 A and  12 A, respectively. In order to abate the entry and exit of particulate matter into and out of the interior of the inflated unit  10 , filters  11 B and  12 B are provided along and traversing the conduit members  11 A and  12 A. 
         [0046]    Also particularly shown in  FIGS. 1 ,  3  and  4 A, an air lock  13  is provided having opening panels  12 B and  12 C to permit entry and exit of a workman into and out of the interior if the inflated unit  10 , without substantial loss of effective inflation pressure within the interior of the unit  10 . 
         [0047]      FIG. 2  is an illustration of the embodiment of  FIG. 1 , in cross-section, to illustrate a workman P during a welding procedure onto a conduit member CT of a subterranean well. 
         [0048]      FIG. 3  is an exterior view of a geometric variant of the invention of  FIGS. 1 and 2 , illustrating the use of modular inflatable members  10 A-E designed to provide a dome-like unit  10 , when assembled and inflated. 
         [0049]    As illustrated in  FIG. 3 , the frame structure  20  consists of two arms  21  and  22  that may be placed in overlapping position  23  relative to one another at the top of the dome unit  10 . When placed on the exterior of the dome unit  10 , the arms  21  and  22  may be secured about the exterior by plurality of lines or ties  23  to securements  40  spaced about the exterior of the unit  10 . 
         [0050]    Alternatively, the arms  21  and  22  may be placed interiorally of the dome configured unit  10 , with like securement to the interior walls of the inflatable members  10 A, etc. 
         [0051]    Now turning to  FIGS. 4B and 4C , there is shown a normally collapsed support tripod framework structure  40  for use interiorally within the pyramid-like unit  10  of  FIG. 4A . The tripod frame structure  40  has three collapsible leg members  41 ,  42  and  43  which may be rotated at connections  41 A,  42 A and  43 A to collapse the unit for storage and transportation, as shown in such position in  FIG. 4C . The framework  40  is either installed after the unit  10  has been inflated, or the unit  10  may be constructed using members  10 A-E being placed around it before inflation. After installation, ties, snaps, or the like (not shown) may be used to secure the respective members  10 A-E to the respective legs  41 ,  42 , or  43 . 
         [0052]      FIG. 5  is an exterior elevational view of a preferred unit  10 , including an exterior support framework  50 . The framework  50  has upper and lower horizontal members  51 ,  52 ,  53 ,  54 ,  55 ,  56 .  57  and  58 . The end horizontal members  57 ,  52 ,  54  and  58  are secured to the other respective horizontal members by means, such as by removable bolts and nuts, or the like, at points  59 ,  60 ,  61 ,  62 ,  63 ,  64  and  65  (final corner securement not shown). Finally, the unit  10  is secured to the framework or structure  50  by means of a series of ties, lines or ropes  70  fastened to the exterior of the unit  10  at securement points  71 . 
         [0053]    As will be appreciated, the invention provides a light weight heat resistant modular device having panels or members that can be provided in a number of convenient sizes and shapes to provide a device that can be easily shipped and assembled in conformity to the individual needs at the work location. While not flame proof, the material used to make the panels or members are contemplated to be flame or fire resistant up to about 1,000 F. Such materials will not combust immediately when exposed to the naked flame, and will cease burning in approximately thirty minutes. The unit  10  as disclosed has an air-lock door system that seals the interior with positive internal pressure. 
         [0054]    It will also be appreciated that several refinements may be made to the preferred and other embodiments, such as by adding window panels. 
         [0055]    Furthermore, it will be appreciated that the fans or blowers may be supplied to areas where there is no space to locate a compressor and the use of rig air is not allowed. 
         [0056]    Additionally, it will be appreciated that the use of the present modularly constructed unit eliminates the need to shut down a platform during welding and other operations. 
         [0057]    The modular unit of the present invention may be used to access doors, utility stations and fire systems regardless of their physical location. It may be used to provide a safe environment for installation of patches on pipe, and/or crossovers over flow lines, as well as repairs to risers and structural welds of numerous kinds. 
         [0058]    Although the invention has been described in terms of the embodiments as shown, the invention is limited only by the scope of the appended claims. Those skilled in the art will readily perceive alternative embodiments once this specification is read and understood.