Abstract:
An apparatus for structural support of process equipment including a unitary structural base. The structural base includes a first surface having a mounting recess shaped to receive a first equipment component and a second surface located on the opposite side of the first surface and having a stiffening rib shaped to provide structural support. The structural base also includes a side surface located between the first and second surface and including an aperture shaped to receive a lifting component.

Description:
BACKGROUND OF THE INVENTION  
         [0001]    1. Field of the Invention  
           [0002]    The present invention relates to a housing system for chemical equipment.  
           [0003]    2. Discussion of the Background  
           [0004]    Chemical processing equipment is generally assembled into complex systems with a large number of valving connections between individual elements with varying functions and attributes. Examples include pressure vessels, compressors, pumps, mixers, chemical reactors, burners, etc. Traditionally, one or more components of the complex system, often referred to as the plant, are delivered to the site of the plant and assembled in situ with independent fluid connections, mechanical supports, weather protection, fire protection, ventilation systems, etc. This method has been employed for many years, and is especially well-adapted to physically-large equipment which must be fabricated on site. For small chemical equipment, this method is far less desirable, as the time and expense required to erect the components in the field can significantly impair the economics of the system.  
           [0005]    Consequently, small subsystems of existing chemical plants are often fabricated at a remote facility, then shipped to the site for final integration. This practice, known as shop fabrication, has been used to reduce the time required to assemble subsystems of plants. Generally, individual “skids,” fabricated manually from structural metal shapes by welding, bolting and similar methods are provided for complete subsystems such as electrical control, compression, pumping, pressure swing adsorption and other processes. For very small plants, complete processes have even been packaged on skids of this type, offering significant advantages over site-erection in terms of reduced assembly time, improved work quality, and reduced worker exposure to the elements on site. Particular examples of plants of this type are compact hydrogen generation plants, pressure-swing adsorption plants for air separation, and water treatment plants.  
           [0006]    Traditional skid construction has many serious drawbacks though. First, the skid is constructed from many structural elements, requiring a great deal of careful manual labor for assembly. Subsequent to this assembly, the individual functional elements of the plant are integrated to the skid with additional labor required to locate and drill mounting holes, attach fasteners, and the like.  
           [0007]    Provision of an outer housing can be difficult, as the dimensional tolerances of such structures can be rather poor, causing problems with fit-up of the housing elements. Many skids are thus left without any weather protection. Even if a cover is fitted, it is generally difficult to make this cover aesthetically-pleasing, due to the limited variety of shapes which can be fabricated using a metal structural frame without substantial outlay of precision labor or large investments in tooling. This is a marked disadvantage if the equipment is to be sited near public areas where aesthetic concerns may be of enormous importance.  
           [0008]    Of equal importance is the issue of protection of the skid-mounted equipment during transit. Traditional skids may provide lifting points, but they are not generally designed to discourage improper load application during shipping. Further, they do not provide any mechanical barrier against damage to the plant and its associated plumbing and wiring interconnects, which are generally susceptible to damage during handling, for example, by impact from a fork truck tine. It is also exceedingly difficult to provide a skid manufactured from individual structural components which is proof against shipping shock which is also light in weight. This results in either relatively massive skids designed to withstand shock loadings, or in less-substantial skids which run the risk of plant damage in transit.  
           [0009]    Another drawback of traditional skids is related to serviceability of the plant components. Existing skids mount each component for full service while attached to the skid itself. This can present a serious difficulty in packaging a plant in a compact fashion for ease of shipment, small installed footprint and aesthetic appeal.  
         SUMMARY OF THE INVENTION  
         [0010]    Accordingly, the present invention advantageously provides an improved mechanical apparatus for structural support of chemical process equipment.  
           [0011]    The present invention further advantageously provides means for lifting the chemical process equipment, which prevents improper handling that may lead to damage or create a safety hazard.  
           [0012]    The present invention also advantageously provides a structural support system substantially lighter than related art apparatuses for equivalent mechanical strength and rigidity.  
           [0013]    Additionally, the present invention provides means to facilitate removal of entire process units as modules for service and/or shipment.  
           [0014]    Additionally, the present invention provides an improved mechanical apparatus for the external housing of chemical process equipment.  
           [0015]    Additionally, the present invention provides a housing that provides protection of the chemical plant during shipment.  
           [0016]    Additionally, the present invention provides a housing that provides protection of the chemical plant from fire hazards.  
           [0017]    Additionally, the present invention provides a housing that provides noise attenuation.  
           [0018]    Additionally, the present invention provides a housing that provides controlled ventilation.  
           [0019]    Additionally, the present invention provides a housing that provides control of electromagnetic interference.  
           [0020]    The present invention further provides ready means of interconnection between the structural support and housing apparatus of the present invention.  
           [0021]    The present invention further provides a housing that can serve to support some or all of the components of the chemical plant.  
           [0022]    The present invention provides an assembled housing and a structural support that facilitate implementation of aesthetically-pleasing shapes.  
           [0023]    The present invention substantially reduces the assembly time for a packaged chemical plant.  
           [0024]    Additionally, the present invention provides a hydrogen generating plant packaged within an improved housing and support system of the present invention. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0025]    A more complete appreciation of the invention and many of the attendant advantages thereof will become readily apparent with reference to the following detailed description, particularly when considered in conjunction with the accompanying drawings, in which:  
         [0026]    [0026]FIG. 1 depicts a unitary structural base of the present invention with a modular subassembly carrier;  
         [0027]    [0027]FIG. 2 depicts an underside of the preferred lightweight unitary base with stiffening ribs and essentially uniform wall thickness;  
         [0028]    [0028]FIG. 3 depict the unitary structural base of the present invention with a system of preferred internal support structures;  
         [0029]    [0029]FIG. 4 depicts the improved structural base with internal support structures and attached outer housing system; and  
         [0030]    [0030]FIG. 5A depicts a front, right, top perspective view of a preferred embodiment of the external housing, and FIG. 5B depicts a rear, left, top perspective view of the housing of FIG. 5A. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0031]    Embodiments of the present invention will be described hereinafter with reference to the accompanying drawings. In the following description, the constituent elements having substantially the same function and arrangement are denoted by the same reference numerals, and repetitive descriptions will be made only when necessary.  
         [0032]    [0032]FIG. 1 depicts a unitary structural base  1  of the present invention. The base  1  includes forklift tineways  2 , which are positioned to provide a secure and stable lifting point. As shown in FIG. 1, each tineway  2  includes an aperture located on a side surface of the base  1 . Each aperture is shaped to receive a lifting component, such as a forklift tine. These tineways  2  are preferably positioned such that the center of gravity of the packaged process plant is between the tineways  2  and near the forklift toward the rear of the unitary base. The unitary base is provided with a large number of component mounting holes  3  and internal support mounting holes  4 . The base may be provided with any number of component mounting recesses  5 , as well as provisions for leveling feet  6 . It may also preferably be provided with a raised sealing feature  7 , which can be used to locate and seal the housing panels  101 ,  102  (shown in FIG. 4) to the unitary base.  
         [0033]    It is most advantageous to provide a removable carrier  9  for any component which may require periodic maintenance or replacement. The carrier  9  is integrated into mating aperture  10  and is preferably attached via fastener holes  11  which are provided in the carrier  9  and around the mating aperture  10 . Secure fastening between these elements can be highly desirable to add stiffness and strength to the assembled elements to protect against damage during transport. Alternatively, some particularly fragile equipment or equipment which generates substantial vibration may be mounted using a removable carrier  9  which is isolated structurally from the unitary base by vibration isolation means to provide protection against shock and/or vibration being transmitted to the equipment during shipment or operation. Examples of preferred vibration isolation means are vibration-damping polymer sheet or combinations of springs and damping elements.  
         [0034]    Both the unitary base  1  and the carrier  9  may be advantageously formed in a near net shape process such as casting, forging, powder metallurgy or molding. Sand casting is an especially-preferred method of manufacture for metal construction. They may be manufactured from metals or reinforced ceramics or polymers. Preferred materials combine high strength and stiffness, low density, corrosion resistance and low cost. Especially-preferred materials include alloys based on aluminum, magnesium or fiber-reinforced polymers. For process equipment which presents a fire hazard, aluminum-alloys are preferred. For process equipment handling materials which attack metals, such as strong acids, fiber-reinforced polymers are preferred.  
         [0035]    Although many component mounting features may be formed in the initial casting or molding process, tolerance limitations may require secondary machining to provide finished features with close tolerances. Computer Numeric Controlled (CNC) secondary operations can provide feature placement to very tight tolerances, and are especially preferred for providing threaded attachment holes  3 ,  4 ,  6  and  11 , mounting pad surfaces  14 , and outer panel sealing surfaces  7 .  
         [0036]    The unitary base  1 , when manufactured using near net-shape processes, has the distinct advantage over structural skids of the related art in that the shape of the perimeter of the unitary base  1  may have essentially any shape, and is not restricted to polygonal shapes such as rectangles. In particular, curved sections  18  in the outer perimeter and compound curved sections  19  may be easily formed. These features can serve structural purposes, such as preventing snagging the exterior of the process plant during transport, or can serve purely aesthetic purposes. The latter is of especial performance in applications where process equipment is to be sited near public places, where aesthetic considerations may be crucial to obtaining permission to install the system.  
         [0037]    [0037]FIG. 2 depicts the underside of the unitary base  1  of the present invention. Although casting and molding can be used to form essentially solid bases with recesses and features provided as noted in FIG. 1, this practice undesirably increases the weight and material cost of the assembled process plant. The increased weight can further exacerbate handling of the plant, increasing the probability of damage during shipment. Preferably, the unitary base is provided with stiffening ribs  20 . These ribs may be strategically-located to reinforce areas around particularly heavy components. Further, the tineways  2  also serve as stiffening features. It should be noted that in sand cast construction of the unitary base, core support points  21  may be added to reduce the probability of defective castings being manufactured. In the preferred embodiment, the unitary base  1  is configured such that the wall thickness is essentially uniform throughout the part, with increases and decreases in thickness occurring gradually in order to promote ease of manufacture through molding or casting.  
         [0038]    [0038]FIG. 3 depicts the unitary base  1  with attached structural frames  31 . These frames are provided with mounting points  32  for outer side panels and holes  33  for attaching the roof panel  201  (FIG. 5A). The structural frames  31  are also provided with a large number of component support holes  35 . All of these features are most preferably provided using computer numeric controlled (CNC) methods such as laser cutting, or punch press work. This allows these features to precisely match the mating holes provided in the unitary base  1 , the housing panels  101 ,  102 , and in the supported components themselves.  
         [0039]    Compared to related art skids which are assembled from standard structural shapes such as square or round tubes or L-shaped structural members, the structural frames  31  of the present invention are preferably formed from plate or sheet metal, or by molding of fiber-reinforced polymers. This allows the shape of the subframes to be optimized for strength and stiffness, while minimizing weight and cost. It is particularly preferred to utilize components, ducting features, and supporting panels to create box structures. For example, internal ducting baffle  36  may be joined to the forward structural supports by fasteners, as well as to the electrical enclosure  37 . The structural supports may also be joined to duct inlet  38 , which may also be joined directly to the unitary base  1 . The resulting structural shape is not only extremely strong and stiff, and much more resistant to damage due to shock loading due to shipping and handling, but is also highly functional. The duct inlet  38  is provided with means to support filters  39  as well as directing the flow of ventilating air to the plant and providing structural support. The ducting baffle  36  is provided with features to support a heat exchanger  40  and to attach an access panel  41  which may be used during maintenance to access internal components inside the plant. All of these functions may advantageously be served by a much reduced set of componentry compared to process plants mounted on skids of the related art.  
         [0040]    [0040]FIG. 4 depicts the unitary base  1  and structural subframes of the present invention with external panels  101 ,  102 , and  206  attached. The external panels are preferably provided with attachment features  110 , which are placed precisely to match the mounting means  45  provided on the structural subframes  31  (shown in FIG. 4). The external panels may be attached by bolts, screws, pins, or any other means of attachment apparent to one skilled in the art. The joints between the external panels, and between the panels and the unitary base may advantageously be provided with weather sealing means such as weather-stripping, caulk or any other means apparent to one skilled in the art. To facilitate proper sealing, the external panels may be provided with sealing features  111 , which may take the form of overlapping seams, or shiplaps. These features have the especial advantage of providing an aesthetically-pleasing seal implementation where the sealing material is not readily visible.  
         [0041]    The external panels of the present invention can serve many purposes. If they are rigidly mounted to at least one of the subframes  31  and the unitary base  1 , they can serve as load-bearing members of the assembly. This is especially advantageous if the panels are provided with stiffening features  112  or curvature  113 . These features advantageously increase the stiffness of the external panels relative to that of planar panels as practiced with polygonal skids of the related art. These combination of high-stiffness external panels and correspondingly high stiffness subframes  31  and unitary base  1  can result in significant increase in the durability of the housing assembly and thus to its resistance to damage due to imposed loads, such as shock loads during shipping. Alternatively, one or more sides of the enclosure may be combined to form larger housing systems, which may cover two, three or more sides of the process plant. Such combination of panels advantageously reduces assembly labor, increases strength and stiffness, and reduces the number of weather seals required. However, the tooling required to form such combined panels may be very expensive, and the combined panels may restrict maintenance access, such that neither method is preferred.  
         [0042]    The external panels of the present invention may be made of any material. Preferably, the panels are made of material which offers one or more of the following attributes: ease of formability; low flame spread; low smoke generation; good sound attenuation; high strength; high stiffness; high toughness; and low density. Most preferably, the panels may be made from fiber or particle reinforced thermoset or thermoplastic polymer resin. Resins which include fire-retardant compounds are especially-preferred. An example of an especially-preferred material is glass fiber reinforced polyesther resin with flame retardant additives. Fire retardancy may advantageously be obtained by providing panels with a layered construction including one or more layers which are essentially incombustible or of very limited combustibility. Examples include the use of fire-retardant polymer foams, glass or mineral fiber batting or board, or powdered ceramic material. A surprising advantage of providing this fire-retardant layer is the concurrent reduction in acoustical transmission in a properly selected enclosure panel. The acoustic attenuation properties of the composite may be modified by varying the thickness, porosity, and density of the insulative material to selectively reduce acoustic transmission in one or more frequency ranges.  
         [0043]    In chemical process equipment which handles flammable materials, it is especially advantageous to provide materials which have static-dissipative properties to prevent the accumulation of static electric charge. This is especially important to provide protection against lightening strike. This may be accomplished by providing enclosure panels made from metals, or by providing non-metallic materials which employ a static-dissipative means. Examples of such means are providing the electrically non-conductive material with a conductive filler, such as carbon or aluminum powder or fibers. Alternatively, static dissipative coatings may be used. It is particularly advantageous to provide a static dissipative means which also serves as a shield against the propagation of electromagnetic noise. This protection may be against noise radiating from sources outside the enclosure, such as radio transmitters, high frequency power supplies, or the like, or against electromagnetic emissions from inside the enclosure such as high-voltage spark igniters for burners. An example of an especially-preferred means for static dissipation and electromagnet noise protection is a copper wire mesh which is assembled to the enclosure panels, and may be manufactured into the panels.  
         [0044]    The external enclosure of the present invention may be manufactured using a variety of methods. It is especially-desirable to employ methods which can produce components with the desirable features described herein without requiring extremely costly and complicated tooling, or inordinate expenditure of manual labor for subsequent finishing and/or assembly of the panels. It is also desirable to employ a method of manufacture which can yield nearly net shape components such as hydroforming of metals, vacuum forming of thermoplastic polymer, or rotational molding of thermoplastic polymer. For the preferred, reinforced polymer materials, means such as hand lay up, spray up, resin transfer molding, or compression injection molding may be advantageously employed. Spray up of reinforced polymers is especially preferred. It is especially preferable to provide an excellent surface finish to the external surfaces of the enclosure. A preferred technique for providing the desired degree of surface finish is the use of a gel coat, which preferably contains pigment, luminescent fillers, or other appearance-enhancing means. Other methods for obtaining the desired surface finish include painting, powder coating, and electroless plating, which can also provide the static dissipative means to the components.  
         [0045]    [0045]FIGS. 5A and 5B depict a preferred embodiment of the assembled enclosure system of the present invention. The enclosure is provided with a front panel  101 , with an integral ventilation inlet louver  200 . This front panel  101  is provided with attachment means  110  (shown in FIG. 4) which facilitate easy removal for maintenance purposes. The sealing shiplap  111  (shown in FIG. 4) is overlapped by the edge of the top panel  201 , and is provided with a compliant sealing material in order to provide a substantially weather-tight seal between the panels. The bottom edge of the panel  101  is provided with a hidden elastic seal which seals the region between the sealing feature  7  of the unitary base  1 . Similar hidden seals are preferably provided between each panel which abuts the unitary base and the base sealing feature  7 . These sealing features may be made externally visible if desired for special aesthetic reasons.  
         [0046]    The back of the enclosure may advantageously be provided with an exhaust louver  204 . In the preferred embodiment of the present invention, a rear access panel  205  is provided which can be separately removed to provide ease of maintenance. A fixed panel  206  is also illustrated which is used to permit permanent attachment of utility interconnections  207 . The location of the access panels and ventilation louvers is dictated by the concerns for the chemical process equipment in question. For process equipment employed in the vicinity of heavier than air flammable vapors, the height of ventilation inlet louver  200  is most preferably at least 18 inches above ground level to protect against the ingestion of such vapors with the ventilation air. For process equipment generating a heated product gas stream, the exhaust louver  204  is preferably sited near the top of the enclosure to ensure rapid dispersal of any heated exhaust and/or any noxious exhaust products. This arrangement of inlet and exhaust louvers is particularly preferred for hydrogen generation equipment. The enclosure of the present invention may most advantageously be employed as a ventilation ductwork to direct ventilation air over the chemical process equipment packaged within. This is particularly preferable when the process equipment presents a risk of leaking flammable or hazardous vapors. Forced ventilation is especially preferred for hydrogen generation plants housed within the enclosure of the present invention.  
         [0047]    It is clear from the preceding description that the integrated structural housing of the present invention can provide an extremely high strength and stiffness by integrating a system including a unitary base with internal structural elements which preferably combine structural features with other functions such as internal flow ducting, and a system of outer enclosure panels which are themselves load-bearing, high-stiffness components.  
         [0048]    It should be noted that the exemplary embodiments depicted and described herein set forth the preferred embodiments of the present invention, and are not meant to limit the scope of the claims hereto in any way.  
         [0049]    Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described herein.