Abstract:
A fume extraction hood is designed to be positioned above a welding, cutting, or other metal-working location and to remove hot gases, smoke and fumes produced during these processes. The hood forms a box-like structure with an extractor rail structure disposed in an internal volume of the hood. The extractor rail structure comprises panels that force sharp turns in the gases, causing particulate matter to drop out of the gases both outside and inside the extractor rail. A primary path for gases accelerates and re-directs the gases entering into the extractor rail, and within the rail. The rail may form a dropout tray that can be removed for cleanout of collected particulate. The side and end rails of the hood may create a secondary path for gas not directly intaken into the extractor rail. This secondary path is re-directed towards the extractor rail, where gas is collected and particulate is forced to drop out as it joins the primary path.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application is a Non-Provisional Patent Application of U.S. Provisional patent application Ser. No. 61/558,856, entitled “Welding Fume Extractor”, filed on Nov. 11, 2011, which is herein incorporated by reference. 
     
    
     BACKGROUND 
       [0002]    The present invention relates generally to welding and other metal-working systems, and particularly to evacuation hoods used in such systems for extracting hot gases, smoke and fumes created during the processes. 
         [0003]    Many welding processes, and similar metal-working operations, have become commonplace throughout industry. In both manual and automated applications, welding often takes place in dedicated locations, sometimes referred to as weld cells, which may include individual welding systems, or more complete production lines for creating various assemblies of workpieces. Most such welding involves metal inert gas (MIG) processes, although other processes including stick welding, tungsten inert gas (TIG) welding, plasma cutting, grinding, and so forth may take place in the dedicated locations. 
         [0004]    In many such settings it is desirable to extract hot gases, smoke and fumes created during the processes, at least, while the process is ongoing. Various hoods, extraction systems, and similar devices have been devised for this purpose. In general, such systems often include a hood or other intake coupled to a conduit that draws the gases, smoke and fumes from the worksite to various filters, blowers, air recirculation and exhaust components. Certain drawbacks are often associated with existing evacuation systems, however. For example, the systems may not accommodate different sizes and configurations of weld cells or welding locations. Moreover, while some screening and filtration may be provided, certain existing systems may allow for the intake of particulate matter and even sparks from the process. It would be advantageous to allow such a particulate matter to be eliminated from the gases extracted from the work location, although existing systems do little to advance this goal. 
         [0005]    There is a need, therefore, for improved extraction systems for welding and similar metal working applications. 
       BRIEF DESCRIPTION 
       [0006]    The present invention provides novel approaches to fume and smoke extraction designed to respond to such needs. The systems are particularly adapted for welding, cutting, and similar metal-working operations that can generate fumes, smoke, hot gases, but also particulate matter and sparks. However, the embodiments described herein may be equally beneficial in any processes that generate fumes, particulate matter, and so forth, during operation. In accordance with certain aspects of the invention, a fume extractor hood includes a box-like structure and an extractor rail structure. The box-like structure has end rails, side rails and a cover, and is configured to at least partially enclose a volume over a welding, cutting or other metal-working process (or any other process, for that matter) that generates fumes and particulate matter during operation. The extractor rail structure is disposed in the volume and configured to draw fumes and particulate towards an inner space from which the fumes are conveyed to exhaust ductwork. The extractor rail comprises a side wall that forces a sharp turn in all fumes drawn into the extractor rail to force dropout of at least some of the particulate matter. An inner passageway between the side wall and a deflector accelerates the fumes entering the extractor rail. Gas entries force a second sharp turn in all fumes drawn into the extractor rail to force dropout of particulate matter entrained with the fumes into the inner passageway. 
         [0007]    In accordance with cetain aspects, the invention offers a fume extractor hood that comprises, as before, and an extractor rail structure disposed in the volume and configured to draw fumes and particulate towards an inner space from which the fumes are conveyed to exhaust ductwork. The extractor rail comprises generally parallel panels that force at least one sharp turn in all fumes drawn into the extractor rail to force dropout of at least some of the particulate matter outside the extractor rail. At least one gas entry forces at least one second sharp turn in all fumes drawn into the extractor rail to force dropout of particulate matter entrained with the fumes to a collection location within the extractor rail. 
         [0008]    In accordance with a further aspect, the invention provides a fume extractor hood that again includes a box-like structure having end rails, side rails and a cover, the box-like structure configured to at least partially enclose a volume over a welding, cutting or other metal-working process that generates fumes and particulate matter during operation, and an extractor rail structure disposed in the volume and configured to draw fumes and particulate towards an inner space from which the fumes are conveyed to exhaust ductwork. The extractor rail comprises walls defining a primary fume path, the side walls being configured and disposed to force a plurality of sharp turns in all fumes drawn into the extractor rail to force dropout of at least some of the particulate matter outside and inside the extractor rail. At least one of the side and end rails comprises a re-directing shape that re-directs fumes in a secondary fume path for fumes not directly entering the extractor rail downwardly and back towards the extractor rail. 
     
    
     
       DRAWINGS 
         [0009]    These and other features, aspects, and advantages of the present invention will become better understood when the following detailed description is read with reference to the accompanying drawings in which like characters represent like parts throughout the drawings, wherein: 
           [0010]      FIG. 1  is a perspective view of an exemplary welding location, in this case comprising a weld cell, with a hood associated with a weld cell for extraction of gases, smoke and fumes in accordance with aspects of the present disclosure; 
           [0011]      FIG. 2  is a perspective view of the hood illustrated in  FIG. 1  as showing certain of the structural components of the hood; 
           [0012]      FIG. 3  is a transverse sectional view of the hood of  FIG. 2 , illustrating internal structures of an extractor rail that draws smoke and fumes from within the hood, while eliminating particulate matter; 
           [0013]      FIG. 4  is a longitudinal section of the same hood, showing the internal components of the extractor rail; 
           [0014]      FIG. 5  is a sectional view through the exemplary extractor rail, illustrating a primary path for the flow of gases through the structure, and rejection of particulate matter; and 
           [0015]      FIG. 6  is a sectional view through the hood structure illustrating a secondary path for gases that are re-circulated within the hood for joining the primary path illustrated in  FIG. 5 . 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Turning now to the drawings, and referring first to  FIG. 1 , an evacuation hood  10  is illustrated above a welding system  12 . In the illustrated embodiment, the welding system is disposed in a weld cell  14  defined by a support structure with panels that least partially surround the welding system. In other installations, the evacuation hood  10  may be provided above welding systems, cutting systems, or other metal-working equipment without surrounding walls, curtains, or the like. However, in many applications it will be useful to provide such isolation from surrounding environments. Moreover, the structure of the weld cell allows for at least partial containment of smoke and fumes created during the metal-working operation. 
         [0017]    It should be noted that while described herein as being used in conjunction with a welding system, in other embodiments, the evacuation hood  10  may be used with cutting systems, other metal-working equipment, or any other equipment that generates fumes and/or particulate matter during operation. As described herein, the terms “particulate” and “particular matter” are intended to cover any and all of the relatively small particles that tend to travel with the gases, smoke, and fumes that are generated by the processes, such as weld sparks, soot, dust, sawdust, and so forth. 
         [0018]    The illustrated weld cell  14  generally encloses an internal volume  16  in which the welding operations are performed. In the illustrated embodiment, again, the operations are performed by a robot in an automated fashion. Such production facilities may include one or more robots, and these may be provided in individual weld cells, or in larger production areas around individual or progressing workpieces or assemblies. However, it should be borne in mind that the evacuation hood and the techniques described in the present disclosure may be equally well applied to manual welding applications, and operations in which a combination of automated and manual work takes place, and so forth. 
         [0019]    The hood  10  illustrated in  FIG. 1  is coupled to conduit or ductwork  18  that aids in evacuation of gases, smoke, and fumes. The ductwork and any downstream components may be essentially the same as those used in conventional systems, allowing for application of suction pressures to pull gases, smoke and fumes from around the welding operation, through screening and filtration components, blowers, and air recirculation and exhaust components. 
         [0020]    The evacuation hood  10  is illustrated in somewhat greater detail in  FIG. 2 . As shown in  FIG. 2 , the hood includes a box-like structure made of a frame  20  which may consist of side rails  22  and end rails  24 . In the rectangular arrangement of  FIG. 2 , the side rails and end rails are essentially identical in section, and may be formed of bent sheet metal or another construction material. Corner joints  26  allow these rails to be joined to one another to form to form the box-like hood. Although not illustrated, straight coupling joints similar to the corner joints may also be used to join rails end-to-end so as to allow creation of hoods of various sizes and shapes. The corner joints  26  in the illustrated embodiment are provided with lifting eyes  28  to allow cranes, hoists, or other equipment to position the hood in the desired location. Similarly, supports  30  may be coupled to the hood, and extend downwardly so as to allow the hood to be rested on underlying support structures, such as the frame of a weld cell. However, it should borne in mind that the hood may be suspended, supported, or otherwise held in place in any suitable manner. 
         [0021]    Between the side and end rails, various braces and struts  32  may be provided to lend structural rigidity to the hood and support for a cover  34  that aids in enclosing the volume immediately below the hood. In the illustrated embodiment the cover  34  is made of a clear polycarbonate material to allow light to penetrate into the work location, while nevertheless capturing gases, fumes, and smoke. The braces and struts  32  aid in supporting the cover  34 , and may be fastened to the cover, such as by clips or other fasteners. In the illustrated embodiment, moreover, side curtains  36  are provided to assist for isolating the internal volume of the hood. These curtains may be short as illustrated in the figures, or may extend downwardly even further to isolate and contain the internal volume. 
         [0022]    Within this internal volume of the hood, and extractor rail  38  is provided. In the embodiment illustration throughout the figures, the extractor rail is disposed in central location transverse to the side rails. The extractor rail comprises structures that aid in the capturing of gases, smoke and fumes, while assisting in rejecting particulate matter, sparks, and the like. An aperture is formed in the cover that communicates with the internal volume of the extractor rail to allow gases to be conveyed to the ductwork as described above with reference to  FIG. 1 . Although a single extractor rail  38  is illustrated in the figures, in practice, numerous extractor rails may be provided, such as for longer or extended hoods. These may be oriented transversely as illustrated in the figures, or longitudinally. Moreover, in many applications it may be warranted to place additional extractor rails over specific locations where welding, cutting, or other metal-working activities will take place. 
         [0023]      FIGS. 3 and 4  are transverse and longitudinal sections of the hood shown in  FIG. 2 , illustrating in somewhat greater detail the internal components of the side and end rails and the extractor rail. Referring to these sectional views, the extractor rail  38  comprises a dropout tray  40  at least partially surrounding a deflector structure  42 . As described more fully below, the dropout tray and deflector structure cooperate to allow channeling of hot gases, smoke and fumes into the extractor rail, while assisting in rejecting particulate matter. Slots  44  are formed in the deflector structure in the illustrated embodiment, and these allow for passage of the gases from internal gas passageways  46  between the dropout tray and the deflector structure into the internal volume of the extractor rail, and therefrom to the associated ductwork. 
         [0024]    The side and end rails in the illustrated embodiment comprise curved or facetted portions that assist in channeling gases toward the extractor rail. That is, as best illustrated in  FIG. 4 , side panels  48  extend from the cover of the hood downwardly, and join one or more lower re-directing panels  50  that deflect gases that are not directly in taken by the extractor rail back towards the extractor rail. 
         [0025]      FIG. 5  is a sectional view of the exemplary extractor rail described above illustrating a primary path  52  for gases, smoke and fumes. Such gases will rise upwardly towards the extractor rail owing to their thermal buoyancy (and the negative pressure created by evacuation of air below the hood), and will be drawn into the extractor rail as illustrated in  FIG. 5 . It is presently contemplated that most of the gases will be drawn in through this primary path. The primary path extends upwardly and around lateral extensions  54  where the path makes a sharp turn inwardly toward the center line of the extractor rail. Much or most of the particulate matter that may be entrained in the rising gases will fall out at this point due to this sharp turn, as indicated by reference numeral  60 . The primary path then extends between a deflector plate  56  of the deflector structure  42  and the lower side of the dropout tray. The gases are accelerated due to a reduced cross-sectional area at this location, and may enter the slots  44  with another sharp turn. The slots  44  are formed between the deflector plate  56  and a base plate  58  of the deflector structure near a lower portion of the deflector plate. In a presently contemplated embodiment, for example, with a gas flow velocity within the hood for good gas capture on the order of at least approximately 45 ft/min, the velocity of the gas in the internal passageway between the side wall of the dropout tray and the deflector plate may be on the order of at least approximately 200 ft/min. The second sharp turn, then, causes the gases to further accelerate angularly, but also, in a presently contemplated embodiment, in speed owing to the dimensions of the slots. For example, in the example discussed above, velocities on the order of at least approximately 3600 ft/min may be reached as the gases pass through the slots. Other velocities may, of course be used, and these may depend upon the capacity of the air-moving components, the ductwork, the volume of gas produced, and so forth. Much of any remaining particulate matter remaining in the gases will dropout at this point, as indicated by reference numeral  62 . The particulate matter  62  will collect below the base plate, and may be cleaned out from time to time. The dropout tray may be made removable for this purpose. Although only one side of the primary path is illustrated in  FIG. 5 , it would be understood that the same flow and particulate rejection occurs on opposite side, the extractor rail in the illustrated embodiment being generally bilaterally symmetrical. Moreover, the slots  44  are disposed along the length of the extractor rail, such that similar gas draw and particulate rejection occurs along the entire length of the rail. 
         [0026]    It is also contemplated that some of the rising gases may not be directly drawn into the primary path, but may escape sideways toward the side and end rails.  FIG. 6  illustrates a secondary path  64  for gases that may be directed back toward the primary path. In particular, such gases will typically rise due to their thermal buoyancy, and impact the cover  34 , being directed therefrom to the side panels  48  of the end and side rails. The lower re-directing panels  50  then channel the gases back toward the center of the hood, or more generally toward the one or more extractor rails that are provided for drawing the gases away. At least some of the particulate matter may dropout of this secondary path as it is directed from the top to the sides and back toward the extractor rail. As the second path joins the first path, then, additional particulate matter may be encouraged to drop from the gases as described above. 
         [0027]    While only certain features of the invention have been illustrated and described herein, many modifications and changes will occur to those skilled in the art. It is, therefore, to be understood that the appended claims are intended to cover all such modifications and changes as fall within the true spirit of the invention.