Abstract:
An apparatus and method for transporting compressed gases or similar materials. The apparatus includes an exterior housing dimensioned for intermodal transportation that contains a rack that holds pressure vessels. The apparatus may be loaded with pressure vessels and the vessels filled within the apparatus. The apparatus may be transferred between modes of transportation along a delivery route without unloading the vessels from the apparatus.

Description:
BACKGROUND 
       [0001]    1. Field of the Invention 
         [0002]    The present invention relates to an apparatus and method for transporting compressed gas. Specifically, embodiments of the invention relate to intermodal containers for transporting compressed gas within pressure vessels and methods for the manufacture and use thereof. 
         [0003]    2. Description of the Related Art 
         [0004]    Gases and similar materials require specialized pressurized containers for transportation. Natural gas and similar materials are often mined at locations that are remote from refineries and storage facilities, as well as the end users of the materials. Large volumes of pressurized gas are transported from field to market using multiple forms of transportation. 
         [0005]    Pipelines are one traditional form of transportation. However, pipelines are expensive and time consuming to install over significant distances. Transportation of gas via pipelines raises political issues relating to the construction and control of the pipeline. Pipelines often pose regulatory and environmental challenges as well. Due to these challenges, the costs of creating and utilizing a pipeline often make them infeasible as solutions in many situations. 
         [0006]    Pressure vessels are another way to transport gas from the field to market. Pressure vessels come in many forms and may be built especially for use with gases stored at very high pressure. Moving compressed gas in pressure vessels over long distances typically requires multiple modes of transportation. The compressed gas within the pressure vessels must be transferred from one mode of transportation to another along the route to the target destination. At each transfer point along the route, the gas must be emptied from one set of pressure vessels and used to fill another set of pressure vessels for the next leg of the journey. For example, a cargo ship having a set of pressure vessels is used to transport compressed gas from its country of origin to a destination country by sea. When the ship arrives at the destination country, the compressed gas is transferred from pressure vessels aboard the cargo ship to pressure vessels aboard a train or truck (i.e., a tube trailer) or into a pipeline for transport deeper into the destination country. Alternatively, the pressure vessels may be physically transferred one by one from the ship to other forms of transportation such as the train or truck. Both of these transfer methods are time consuming and require specialized equipment for pumping the materials in the vessels or transferring individual pressure vessels. This increases the cost of shipping the materials in the pressure vessels. 
     
    
     
       DESCRIPTION OF THE DRAWINGS 
         [0007]    Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that different references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references mean at least one. 
           [0008]      FIG. 1  is a diagram of one embodiment of an intermodal transportation unit. 
           [0009]      FIG. 2A  is a diagram of one embodiment of the intermodal transportation unit with a manifold and access panel. 
           [0010]      FIG. 2B  is a diagram of one embodiment of the intermodal transportation unit without doors and without a manifold to show the rack structure. 
           [0011]      FIG. 3  is a diagram of one embodiment of a pressure vessel. 
           [0012]      FIG. 4  is a flowchart of one embodiment of a process for constructing an intermodal transportation unit. 
           [0013]      FIG. 5  is a flowchart of one embodiment of a process for transporting a material using an intermodal transportation unit. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    In the following description, for the purpose of explanation, numerous specific details are set forth to provide a thorough understanding of the various embodiments. It will be apparent to one of ordinary skill in the art that the embodiments may be practiced without some of these specific details. In other instances, certain structures and devices are omitted or simplified to avoid obscuring the details of the various embodiments. 
         [0015]    The following description and the accompanying drawings provide examples for the purposes of illustration. However, these examples should not be construed in a limiting sense as they are not intended to provide an exhaustive list of all possible implementations. 
         [0016]      FIG. 1  is a diagram of one embodiment of an intermodal transportation unit  100 . The intermodal transportation unit  100  may include an exterior housing  119 , such as a 688 dry van container. In one embodiment, the exterior housing  119  may be cuboid in shape, such as a box or similar shape. In other embodiments, the exterior housing  119  may have other geometric shapes or irregular shapes. In one example embodiment, the external housing  119 , such as the 688 dry van container may be approximately twenty or forty feet in length (dependent on model), eight and a half feet in height and eight feet wide. The intermodal transportation unit  100  may have any dimensions suitable for its purpose. The intermodal transportation unit  100  may be sized to fit specific modes of transport such as truck trailers, train cars, ship holding areas and similar modes of transportation. In another embodiment, the intermodal transportation unit  100 , may be designed to be used with multiple modes of transport meeting the restrictions of each mode. 
         [0017]    The external housing  119  may include a frame  103  and a set of sidewalls  105 . A set as used herein may refer to any number of items including one item. The frame  103  may be made of a high strength metal such as steel, alloys thereof, titanium, iron or similar materials. The side panels  105  may be formed from metals, plastics or other similar materials. In one embodiment, the frame  103  and side panels  105  may be made from non-combustible or flame retardant materials to protect the contents from fire. The external housing  119  also serves to protect the contents from theft, weather, impact, or similar hazards and masks the identity of the contents and provides similar benefits. 
         [0018]    In one embodiment, the side panels  105  may be removeably attached to the frame  103  or fixed to the frame  103  by welding, riveting or similar attachment mechanisms. In one embodiment, the frame  103  and sidewalls  105  may form a complete enclosure. This enclosure may be water tight, air tight, weather proofed or similarly sealed. Extra panels may also be present in the sidewalls including the ceiling and floor panels to protect the contents from heat, cold, forced entry, impact or similar conditions and events. 
         [0019]    In one embodiment, the external housing  119  may reduce the effects of a nearby heat source such as a fire. The intermodal transportation unit  100  has been tested by being exposed to a pan fire test conducted by the Office of Hazardous Material Technology. In the test, the pan holds 150 gallons and is 12 foot by 24 foot in size. 150 gallons of Jet A fuel are burned in the pan over a period of thirty minutes. A pressure vessel exposed directly to this heat source reached a peak temperature of 1161 degrees Fahrenheit. A pressure vessel on a conventional truck trailer reached a peak temperature of 1005 degrees Fahrenheit when exposed to the same conditions. However, a pressure vessel in the intermodal transportation unit  100  exposed to the same conditions maintained a temperature below 225 degrees Fahrenheit for the full thirty minutes. These tests provide an example of the fire protection attributes of an intermodal transportation unit  100  containing a set of pressure vessels. In other embodiments, similar fire protection is provided for other types of objects that may be placed within the intermodal transportation unit  100 . 
         [0020]    In one embodiment, the external housing  119  may include a set of front  101  and rear doors  107 . The doors  101 ,  107  may be removeable side panels, hinged doors, sliding doors or similar types of doors or access panels. In another embodiment, other side panels may be configured as doors or access panels. In a further embodiment, only a single set of doors may be present to allow access to the pressure vessels  111  within the exterior housing  119 . Doors and access panels may have locking mechanisms or similar mechanisms to secure the internal components of the unit. 
         [0021]      FIG. 2A  is a diagram of one embodiment of an end view of an intermodal transportation unit showing a set of doors with an access panel. The doors  107  open and close to provide access to the contents of the intermodal transportation unit  100 . In one embodiment, the doors  107  may include a smaller access panel  257 . This panel  257  may be connected by hinge, by slide mechanism or similar attachment mechanism that allows the access panel to be opened. The access panel  257  may be used to gain access or limited access to the interior compartment of the intermodal transportation unit  100  if the doors are closed. 
         [0022]    In one example embodiment, the access panel  257  may be used to connect a set of pressure vessels and a manifold  251  connected to those pressure vessels to an external pump to load or unload the contents of the pressure vessels. The pump may be connected to the manifold  251  through the port  255  created by the open access panel  257  through a hose  253  or similar mechanism. This increases the ease in which the contents of the intermodal transportation unit  100  may be loaded and unloaded. In one example use, the access panel  257  may be used to connect the pressure vessels to a pumping system on a transport such as a ship. Each pressure vessel may be individually accessed by a pumping system or a central valve may be present in the manifold to allow simultaneous access to the pressure vessels. 
         [0023]    Returning to a discussion of  FIG. 1 , in one embodiment, the intermodal transportation unit  100  may include a rack to hold a set of pressure vessels  111 . The rack may include a set of stands  109 A,  109 B each supporting a set of crossbars. The stands  109 A,  109 B may be independent of one another or may be connected to one another for support.  FIG. 2B  is a diagram showing one embodiment of a configuration of the rack  200 . In one example embodiment, the rack  200  may include four crossbars  201  creating three rows for storing pressure vessels  111 . Any number of crossbars  201  may be utilized dependent on the size of the intermodal transportation unit  100  and the size of the pressure vessels  111 . Also, additional vertical bars or stands may be utilized in the rack to provide additional support to the pressure vessels  111 . For example, a set of stress rods  211  may reinforce the stand  109 . Any number of stress rods  211  may support the rack  200 . Any number of columns of pressure vessels may be defined by the rack  200 . The stand  109 B, crossbars  201  and stress rods  211  may be formed from metals such as steel or aluminum, or other similar materials with sufficient material strength to support the weight of a set of pressure vessels  111 . For example, the stress rods  211  may be ⅞ inch diameter steel rods. 
         [0024]    Crossbars  201 , stress rods  211  and stands  109 A,  109 B may be welded together, interlocking or similarly connected. In one embodiment, the connections may be reinforced by bolts through the joints between the crossbars  201 , stress rods  211  and stands  109 A,  109 B. In one embodiment, the holes may be drilled and the bolts  213  inserted after the rack has been loaded and compressed by a compression mechanism  215  or preloaded to simulate the weight of full pressure vessels. For example, a bottom row of the rack  200  may be loaded with pressure vessels and a crossbar placed over them. The next row is loaded on a crossbar placed over the pressure vessels. This process may repeat until all the rows are loaded. The compression mechanism  215  may exert pressure on a top crossbar to settle the pressure vessels into place and exert a compressing force to hold them in place. The compression mechanism  215  holds or clamps the rack  200  and the pressure vessels on the rack  200  in a compressed or secure position. The holes for the bolts may then be drilled and the bolts  213  inserted to hold the structure in place. The compression mechanism  215  may be any tightening or force exerting mechanism including a clamping mechanism, spring mechanism, tightening bolt or similar compression mechanisms. 
         [0025]    In one embodiment, the reinforcement provided by the stress rods  211  may improve the strength of the intermodal transportation unit  100  in the event of a rollover. The combination of the crossbars  201  and stress rods  211  maintain the shape of the rack  200  and protect the pressure vessels  111 . This structure also assists in holding the pressure vessels  111  in place when placed under the stress of sharp turns or impacts. 
         [0026]    In one embodiment, each crossbar  201  may have a set of positioning members  203 A,  203 B. The positioning members  203 A,  203 B may have a shape complimentary to the exterior cross-sectional shape of the pressure vessels  111  to secure the pressure vessels  111  during transport. The positioning members  203 A,  203 B may be attached to the crossbars  201  by welding, adhesion, riveting or similar attachment mechanisms. In another embodiment, the positioning members  203 A,  203 B may be integrally formed with the crossbars  201 . The positioning members  203 A,  203 B of each crossbar  201  define the placement of the pressure vessels  111  within the rack  200 . Any number of pressure vessels  111  may be accommodated by the rack  200  dependent on the size of the intermodal transportation unit  100 , size of the pressure vessels  111  and spacing of positioning members  203 A,  203 B. 
         [0027]    In one embodiment, a set of friction members  205 A,  205 B may be attached to the positioning members  203 A,  203 B to reduce the longitudinal movement of the pressure vessels  111  during transport. The friction members  205 A,  205 B may be a natural material such as rubber, a synthetic material or any material capable of providing sufficient surface friction to prevent or minimize the longitudinal movement of the pressure vessels. In one embodiment, the friction members  205 A,  205 B may have elastomeric properties to accommodate expansion of the tubes during filling or due to changes in temperature. The friction members  205 A,  205 B may be welded, adhered, form fit or similarly attached to the positioning members  203 A,  203 B. The friction members  205 A,  205 B may be friction enhancing cushions and provide padding to cushion the pressure vessels  111  during transport. In one embodiment the friction members may be made of tire rubber. 
         [0028]    Returning to the discussion of  FIG. 1 , the rack stands  109 A,  109 B may be positioned adjacent to each end of the pressure vessels  111  to provide a level support for each pressure vessel  111 . In one example embodiment, two stands  109 A,  109 B are present in the intermodal transportation unit  100 . In another embodiment, any number of stands may be utilized along the length of the pressure vessels  111  to provide support during transport. In one embodiment, the rack stands  109 A,  109 B provide support and secure the pressure vessels  111  along a body portion of the pressure vessels and do not support the pressure vessels  111  at the neck portion. Supporting the pressure vessels  111  in the neck portion may cause a higher level of wear and limit the lifespan of the pressure vessels. 
         [0029]      FIG. 3  is a diagram of one embodiment of a pressure vessel  111 . The pressure vessel  111  may have a body portion  301  and a neck portion  303 . The neck portion  303  defines an opening for filling and empting the vessel  111 . The pressure vessel  111  may include an inner core  305 . The inner core  305  may be composed of steel, steel alloys, carbon steel, monel, inconel, hastelloy, titanium and similar materials. The inner core  305  may be encased in a composite reinforcement layer  307 . The composite reinforcement layer  307  may be an isopolyester resin matrix, polyester, aramid or other fiber material or similar composite materials. A third layer of woven reinforcement tape  309  may also be placed over the composite layer  307 . In another embodiment, the reinforcement lay  309  may be omitted. 
         [0030]    In one embodiment, the inner core  303 , composite layer  307  or woven tape layer  309  may be formed with a thickened wall or region in at least one segment along the length of the pressure vessel  111 . The thickened wall may form an annular protrusion  311  from the surface of the pressure vessel  111 . In another embodiment, the protrusion  111  may have other shapes such as a set of bumps in an annular pattern. Any number of thickened walls may be formed in the pressure vessel  111 . The thickened walls may also be positioned at any point along the length of the pressure vessel. 
         [0031]    The pressure vessel  311  may have a tube or other elongated shape. The pressure vessel  311  may have any dimensions and shape suitable for providing sufficient strength for storing pressurized materials and for ease of transportation. The pressure vessel  111  may have a single opening in the neck portion. The opening may be fitted with a stop or valve to control the release and fill of the vessel  111 . In another embodiment, the pressure vessel  11  may have a neck and opening at each end. Each opening may be fitted with a stop or valve to control the release and fill of the vessel  111 . 
         [0032]    Returning to the discussion of  FIG. 1 , the pressure vessels  111  are restricted in longitudinal movement with relation to the rack by a combination of the friction members attached to the positioning members and the thickened wall forming protruding sections  113 A,  113 B on each pressure vessel  111 . The protruding sections  113 A,  113 B may be positioned on either side of the positioning members and friction members to inhibit longitudinal movement in either direction. The protruding sections  113 A,  113 B may both be adjacent to the positioning members of the stand  109 A in any combination of positions including both being inside of the positioning members, both being outside and one being outside and the other inside. Additional combinations may be formed if additional protrusions, for example one on either side of a positioning member, or additional stands are present. 
         [0033]    In one embodiment, the rack stands  109 A,  109 B may be secured to the exterior housing  119  through a bracket, pin, riveting, welding, or other stop or attachment mechanism. In one example embodiment, the rack stands  109 A,  109 B may be secured to the exterior housing  119  through a z-bar  115  and screw or rivet  117 . The z-bar  115  may prevent the longitudinal movement of the rack during transportation in relation to the exterior housing. The attachment mechanism may be placed at the base of each stand  109 A,  109 B. In other embodiments, attachment mechanisms may secure the stands  109 A,  109 B along other portions of the rack such as the top of the stands or the sides of the stands. Any number of attachment mechanisms may be used to secure the rack. In one example embodiment, a set of bolts  121  may extend through the external housing  119  into the stands  109 A,  109 B. The bolts  121  may be inserted after loading and clamping the rack  200  with a compression mechanism or prior to loading and clamping the rack  200 . Holes may be drilled through the external housing and into the stands  109 A,  109 B to allow the bolts  121  to be inserted. In one example embodiment, six inch washers may be placed between the external housing  119  and the head of the bolt  121 . 
         [0034]    In one embodiment, the intermodal transportation unit  100  may include a set of strong points for use in moving the unit. These strong points, e.g. corner castings, may be used by cranes or lifting machines for moving the unit without damage to the unit and its contents. These strong points may be positioned at any point on the intermodal transportation unit  100 . The strong points may be fitted with hooks, loops or similar mechanism to facilitate lifting and moving the unit  100 . 
         [0035]      FIG. 4  is a flowchart of one embodiment of a process for constructing an intermodal transportation unit. In one embodiment, a portion of the exterior housing may be assembled such as the floor and sides or the entire exterior housing (block  401 ). A rack may then be installed into the exterior housing (block  403 ). The rack may be installed as a single unit or may be installed in sections such as stand by stand and crossbar by crossbar. The rack may then be secured to the exterior housing (block  405 ). The rack may be secured by any type of attachment mechanism. For example, a set of z-bars or bolts may be used to attach the rack stands to the exterior housing. 
         [0036]    In one embodiment, the pressure vessels may then be placed in the rack (block  407 ). The positioning members may be adjustable or the crossbars and stress rods in the rack may be adjustable to facilitate the placement of the pressure vessels in the rack. In another embodiment, the pressure vessels may be placed in the rack prior to its installation into the exterior housing. After each pressure vessel is placed in the rack or after all of the pressure vessels have been placed in the rack, the pressure vessels may be secured within the rack (block  409 ). The pressure vessels may be secured by tightening the positioning mechanisms or crossbars or through similar mechanisms. 
         [0037]    In one embodiment, after the pressure vessels are secured within the rack they may be enclosed by the exterior housing (block  411 ). The exterior housing may be completed by adding missing portions such as the top or side. In another embodiment, the rack may be loaded through the front or rear doors or other access panel. The front or rear doors may be closed or the access panel reattached to complete the enclosure. 
         [0038]      FIG. 5  is a flowchart of one embodiment of a process for use of the intermodal transportation unit. In one embodiment, after the intermodal transportation unit has been constructed it may be loaded unto a first form of transportation, such a truck, train or ship (block  501 ). Any type of transport vehicle may be used. The unit may be moved by a lift, crane or similar machinery. The machinery used for the movement of the unit may be general use moving machinery instead of machinery specialized for the movement of pressure vessels. 
         [0039]    After the intermodal transportation unit has been properly loaded onto the first vehicle, the pressure vessels may be filled with a material to be shipped (block  503 ). All vessels may carry the same materials or different vessels may carry different materials or amounts of materials. The pressure vessels may be filled one by one or several or all of the vessels may be filed at the same time. The vessels may be filled through an external system that connects to the neck portion and the stops or valves attached to the vessels. The external filling system may access the pressure vessels through a front or rear door or other access panel of the unit. In another embodiment, the vessels may be filled prior to being loaded into the intermodal transportation unit. In a further embodiment, a portion of the filling system may be integrated or attached to the intermodal transportation unit. 
         [0040]    After the vessels are filled or at least a portion of the vessels are at least partially filled, the intermodal transportation unit may be closed to completely enclose the pressure vessels (block  505 ). The unit may be closed by closing and securing doors or replacing and securing an access panel or through a similar mechanism. 
         [0041]    The intermodal transportation unit may be transported to an intermediate location or a first destination by the first mode of transportation (block  507 ). At the first location, a determination is made as to whether a delivery of materials is scheduled (block  509 ). If a delivery is scheduled, then the intermodal transportation unit is opened and the appropriate amount of materials, either a portion or the whole, are emptied from the appropriate pressure vessel (block  511 ). 
         [0042]    After delivery, or if no delivery is scheduled at the location, then it is determined if the final destination has been reached (block  513 ). If the final destination has been reached then the intermodal transportation unit may be taken to the start of a new delivery route (block  515 ). This may include transferring the unit to a new form of transportation or the start of the new route may be the current location, the final destination. The new form of transportation may be a truck, train, ship or similar vehicle. The new form of transportation may be of the same type but a different vehicle. For example, the intermodal transportation unit may be moved from one truck to another or from one ship to another. At the start of the new route, the process may continue by filling the vessels (block  503 ). 
         [0043]    If the final destination has not been reached, then a determination may be made to transfer the intermodal transportation unit to a new form of transportation (block  517 ). If the unit is not to be transferred, then the unit is dosed (block  505 ) and transported to the next location (block  507 ). This process may continue until the destination is reached. 
         [0044]    If the unit is to be transferred, then the unit is closed (block  519 ) and then transferred to the new form of transportation (block  521 ). The intermodal transportation unit may be moved by standard lifting and moving equipment. The new form of transport may be any type of vehicle including the same type of vehicle from which it is transferred. After transfer, the new form of transportation may take the unit to the next location (block  507 ). This process may continue until the destination is reached. 
         [0045]    In the foregoing specification, the embodiments of the invention have been described with reference to specific embodiments thereof. It will, however, be evident that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention as set forth in the appended claims. The specification and drawings are, accordingly, to be regarded in an illustrative rather than a restrictive sense.