Abstract:
A mobile barrier for use in wind control, reduction of blowing litter and suspension and transport of airborne contaminants with applications in areas of landfill maintenance, agriculture, erosion control, and snow control is described. The mobile barrier is a large mesh panel supported in an orientation which is at a slight angle to the vertcial. The panel is supported using a pair of upright members which extend upward from a base which is freestanding. A vertically adjustable lifting boom is also supported by the upright members, and is used to secure the mobile barrier to lifting machinery for purposes of transport. Further, a system for controlling the spread of wind-borne contaminants will be described which includes a mobile barrier in combination with a misting device.

Description:
This application claims the benefit of U.S. Provisional Application Number 60/376,487 filed on Apr. 30, 2002 and U.S. Utility Application Number 10/426,190 filed Apr. 30, 2003.  
       [0001]     This invention relates to control of blowing litter from sanitary landfill operations, specifically to an improved mobile barrier to reduce blowing litter. This invention also relates to control of wind in the presence of earthwork, landfill, and surface mining operations, specifically to an improved mobile barrier to reduce wind speed and thereby reduce suspension and transport of airborne contaminants from these operations. Further, this invention relates to a misting system that is externally mounted to the mobile barrier to further reduce airborne emissions from these operations. Lastly, this invention relates to control of wind in the fields of agriculture, erosion control, and snow control. 
     
    
     BACKGROUND OF THE INVENTION  
       [0000]     Control of Litter  
         [0002]     As sanitary landfills continue to grow higher in elevation, and as surrounding areas continue to be developed, landfill operators are facing increasing problems with blowing litter. Blowing litter causes complaints from neighbors, citations from regulatory agencies, and labor cost to clean it up. Landfill operators use operational precautions, such as coordinating waste receipts and waste placement with wind conditions, to control blowing litter. However, extreme winds, or any winds during a lapse in these precautions, can cause litter transport far beyond landfill boundaries. Landfill operators also use stationary fencing around the perimeter of a landfill site to control blowing litter. However this fencing is only partially effective. The fencing is stationary and cannot be moved to adjust to changing site and wind conditions. It is also often far away from the active waste face, the source of the litter. Litter often blows upward and outward from the active face, high above and over stationary fencing.  
         [0003]     Landfill operators also fabricate large mobile barriers on-site, in a variety of forms and dimensions, to reduce blowing litter. These devices consist of a steel skid or truck and framework to position and support a large area of open screen material downwind of the active waste face. The screen material is typically chain-link fencing, welded wire, expanded steel, or plastic construction fencing. The screen lets wind pass through, but stops litter. There are a variety of methods to move these mobile barriers to adjust to changing site and wind conditions. Some mobile barriers are mounted on skids, while others are mounted on a passive truck with wheels and tires. These mobile barriers can be pulled or pushed over the ground. Yet other barriers have a lifting bale that provides for picking up and moving the barrier with the blade of a bullzoder or landfill compactor (hereinafter “machine”). These mobile barriers can prevent litter from blowing beyond landfill boundaries. However they have several common deficiencies that impair their performance and utility:  
         [0004]     They are not as mobile as they need to be. They lack provisions for readily moving them to the most appropriate location to adjust to changing site and wind conditions, in time to be effective. Barriers on skids or trucks are difficult and time-consuming to pull or push across unstable ground without sticking or damage. Tires become punctured and flattened when rolled over refuse. Pulling these barriers requires the machine operator to dismount the machine to hook up to the barrier. This is undesirable in areas of treacherous ground or during inclement weather. Lifting bales are not adjustable and can only accommodate one particular machine. Also, the bales are usually on the downwind side of the barrier, requiring the machine to traverse around the barrier to pick it up. Because of these difficulties the barriers typically stay in one place even as the waste face constantly moves throughout the life of the landfill and as wind conditions change. Therefore they are seldom positioned in the most appropriate location to effectively control litter.  
         [0005]     They are not suitable for positioning close to, or within, the active waste face that is the source of the litter. They sink into unstable refuse or ground, get stuck, or tip over. They are difficult to remove or right without damage. Consequently they are positioned at some distance from the active face, in more stable ground. This substantially increases the perimeter along which they are to intercept blowing litter, thereby requiring more barriers than if they could be positioned closer to the active face. As blowing litter rises outward and upward from the active face, it is more likely to blow high above and over these mobile barriers.  
         [0006]     Their screens have catches, pinch points, and obstructions that tend to trap litter against the screen, even after the wind has subsided. This “blinding” is unsightly, reduces effectiveness of the barriers, and increases wind loads, making the barriers prone to tipping.  
         [0007]     Plastic construction fencing is prone to wind buffeting and resulting premature failure.  
         [0008]     Their designs do not consider the full loading of high winds and they are therefore prone to tipping.  
         [0009]     They are difficult to position end-to-end with the result of allowing gaps in coverage. Consequently litter blows through, between the ends of multiple barriers.  
         [0010]     They are not matched in scale to the heavy machinery with which they are used. They are often frail structures in comparison to these machines, difficult to see and easy to damage.  
         [0011]     They have no provisions for convenient disassembly and reassembly that would be necessary, because of their large size, to ship them to or from landfill sites. By “convenient” I mean that disassembly and reassembly would require no cutting or welding of steel. Consequently they must be custom-fabricated on-site, generally under inadequate conditions to produce effective barriers at reasonable cost. Therefore the barriers do not lend themselves to economies of standardization, interchangeable parts, mass production, and shipping efficiency.  
         [0012]     Known mobile barriers can control blowing litter. However, the aforementioned deficiencies impair their performance and utility to the point where they are not very effective. Ineffective litter control is a liability to the landfill operator in the form of neighbor complaints, regulatory citations, and clean-up costs. Therefore there is a need for an improved mobile barrier to control blowing litter.  
         [0000]     Control of Wind  
         [0013]     As public awareness of air quality continues to increase, and as governments respond with stricter laws and regulations, suspension and transport of airborne contaminants is an increasing problem for earthwork, landfill, and surface mining operations. The airborne contaminants are typically gasses, vapors, dust, and litter. Controlling wind across the active face of these operations can reduce suspension and transport of these contaminants.  
         [0014]     Wind barriers can control wind speed across the active face of earthwork, landfill, and surface mining operations, thereby reducing suspension and transport of airborne contaminants. Wind barriers are also known in the fields of agriculture, erosion control, and snow control. In these applications, they protect sensitive crops from wind damage, protect sensitive soils from wind erosion, and prevent snow drifting over roads.  
         [0015]     Known wind barriers consist of stationary fencing of wind-reducing lath or fabric. The lath or fabric has an “aerodynamic opacity” that lets some wind through, thereby reducing wind speed without causing turbulence. They are installed upwind of an active face. These barriers can reduce suspension and transport of airborne contaminants beyond site boundaries. However they have some deficiencies that impair their performance and utility:  
         [0016]     Because of their aerodynamic opacity they are prone to high wind loads, often resulting in damage, tipping, and failure.  
         [0017]     The wind-reducing fabric is prone to wind buffeting and resulting premature failure.  
         [0018]     They are not suitable for positioning close to, or within, the active face that is the source of the airborne contaminants. This substantially increases the perimeter along which they are to control wind, thereby requiring more barriers than if they could be positioned closer to the face.  
         [0019]     They are not mobile and therefore cannot adjust to changing site and wind conditions.  
         [0020]     Although they reduce suspension and transport of airborne contaminants, such suspension and transport remains a significant problem.  
         [0021]     Known wind barriers can control wind, thereby reducing suspension of airborne contaminants from earthwork, landfill, and surface mining operations. However, the aforementioned deficiencies, particularly their lack of mobility, impair their performance and utility to the point where they are not very effective. Ineffective control of airborne contaminants is a liability to these operations in the form of neighbor complaints and regulatory citations. Therefore there is a need for an improved mobile barrier to control wind and to reduce and control airborne contaminants.  
         [0000]     Misting Systems  
         [0022]     Misting systems are a known means to control suspension and transport of airborne contaminants from earthwork, landfill, and surface mining operations. They work in two ways: wetting and cooling. Misting systems control dust by wetting dust particles with water mist, thereby adding weight to the particles and providing adhesion between particles. In this case the misting system produces fluid droplets which are relatively large. In cooling applications, misting systems control volatilization of gasses and vapors by evaporative cooling thereby reducing volatilization rates of the source. Misting systems may also be used to dispense odor suppressants into the air, thereby reducing offensive odors from landfills and the like. Misting systems have also been used to dispense bird repellents to control the feeding of seagulls and other avian species at landfills. In the cases of odor and bird control and evaporative cooling, the misting system produces fluid droplets which are very small.  
         [0023]     There are several disadvantages to known misting systems. The most important disadvantage occurs when misting systems are used in open air operations. Frequently mist applied in open air operations is blown away by wind before it has beneficial effect, and it is difficult to retain the mist where it is needed. There are also problems with autonomy and mobility of known misting systems. Known systems usually rely on external power and water and are not suited to moving around a landfill, for example, on a daily basis. Lastly, most commercially available systems lack convenient operational control and are prone to excessive water consumption and accumulation on the ground.  
       SUMMARY OF THE INVENTION  
       [0024]     The present invention is directed to an improved mobile barrier which is uniquely designed to control blowing litter, wind speed, and turbulence. The mobile barrier consists of a mesh panel supported in an orientation which is at a slight angle to the vertical. The panel is supported using a pair of upright members which extend upward from a base which is freestanding and provides a large footprint. A vertically adjustable lifting boom is also supported by the upright members, and is used to secure the mobile barrier to lifting machinery for purposes of transport. Further, a system for controlling the spread of wind-borne contaminants will be described which includes a mobile barrier in combination with a misting device.  
         [0025]     Several objects and advantages of my improved mobile barrier are:  
         [0026]     It is truly mobile and easy to move to the most appropriate location. This allows real-time adjustment to changing site and wind conditions. It has an adjustable lifting boom that can accommodate a variety of machines, from a small machine like a Caterpillar D5 bulldozer, to a large machine like a Caterpillar 836 landfill compactor. The lifting boom is on the front side of the barrier where the machines are working and therefore does not require traversing around the barrier to pick it up.  
         [0027]     It is suitable for positioning close to, or within, the active face, thereby increasing effectiveness of control of litter and wind. It has a smooth stable base that is not prone to sticking, sinking, or tipping in unstable ground. Should these occur, the robust base, uprights, and lifting boom provide for easily removing or righting the barrier without damage.  
         [0028]     It has screen panels that are planar and free of catches, pinch points, and obstructions that tend to trap litter against the screen, even after the wind has subsided. This provides for better appearance, and reduces wind loads and tipping.  
         [0029]     It has screens that are made of steel and not prone to wind buffeting and failure.  
         [0030]     It has a wide stable base and is less prone to tipping in high winds.  
         [0031]     It provides for multiple barriers to be easily positioned end-to-end, with a slight overlap. This prevents litter and wind from blowing through, between the ends of multiple barriers.  
         [0032]     It is matched in scale to the machines with which it is used. It is a robust structure that is easy to see and less prone to damage by these machines.  
         [0033]     It provides for convenient disassembly and reassembly, requiring no cutting or welding of steel. It folds compactly, and multiple folded units stack securely, so that six complete units will fit on a standard 8′×40′ trailer, with no blocking, bracing, or cribbing. These advantages provide for off-site fabrication; and economies of standardization, interchangeable parts, mass production, and shipping efficiency. For example they can be moved from site to site as necessary.  
         [0034]     It has interchangeable screen panels that allow for dual use of the barriers. “Open” panels provide for controlling litter. “Closed” panels provide for controlling wind.  
         [0035]     When a mobile barrier is equipped with a misting system, the combination mobile barrier-misting device is an autonomous, mobile system allowing easy movement and operation throughout a site.  
         [0036]     When the mobile barrier is equipped with a misting system, the combination mobile barrier-misting device prevents the wind from blowing the mist away and thereby retains mist where it is needed.  
         [0037]     It is convenient to think of my mobile barrier as a delivery system that is optimized to position and support a relatively fragile screen material in the rugged environments of earthwork, landfill, or surface mining operation. This design approach distributes the weight of mobile barrier downward and outward, providing for durability and stability of the mobile barrier as a whole. The delivery system is also optimized for shipping efficiency. Further objects and advantages of my improved mobile barrier will become apparent from consideration of the drawings and ensuing description. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0038]      FIG. 1 . Front perspective view of the mobile barrier.  
         [0039]      FIG. 2 . Rear perspective view of the mobile barrier.  
         [0040]      FIG. 3 . Front perspective view of the base and upright support bracket.  
         [0041]      FIG. 4 . Side view of the base and upright support bracket.  
         [0042]      FIG. 5 . Partial front perspective view of the mobile barrier illusrating the adjustable boom and upper panel support mounted to the upper end of the uprights.  
         [0043]      FIG. 6 . Side view of  FIG. 5 .  
         [0044]      FIG. 7 . Side view of upper panel support.  
         [0045]      FIG. 8 . Side view of lower panel support.  
         [0046]      FIG. 9 . Front view of panel illustrating four sub panels and partial overlay of open screen.  
         [0047]      FIG. 10 . Partial detail view of open screen.  
         [0048]      FIG. 11 . Partial detal view of closed screen.  
         [0049]      FIG. 12 . Front perspective view of a single mobile barrier in folded configuration.  
         [0050]      FIG. 13 . Side view of  FIG. 12 .  
         [0051]      FIG. 14 . Front perspective view of three mobile barriers in folded and stacked configuration.  
         [0052]      FIG. 15 . Side view of  FIG. 14 .  
         [0053]      FIG. 16 . Front perspective view of the mobile barrier with the misting system mounted thereon, illustrating the spray bar mounted on the front face of the panel.  
         [0054]      FIG. 17 . Rear perspective view of the mobile barrier with the misting system mounted thereon, illustrating the water tanks, pump, and power unit mounted on the base.  
         [0055]      FIG. 18 . Partial side sectional view of the upper panel support member illustrating the stud of the upper panel support positioned within a slot formed in the cross tube of the panel.  
         [0056]      FIG. 19 . A mobile barrier being lifted by the blade of a bulldozer, illustrating the position of the top edge of the bulldozer blade within the hook portion of the adjustable lifting boom, and the position of the lower edge of the bulldozer blade against the brace channel of the upright support bracket  
         [0057]      FIG. 20 . Multiple barriers in use around an active face, illustrating barriers used for wind control upwind of the active face, and barriers used for litter control downwind of the active face. 
     
    
     DESCRIPTION OF THE INVENTION  
       [0058]     The present invention will now be described with reference to the figures.  
         [0059]     The assembled mobile barrier  10  consists of six discrete weldments of steel, and steel hardware to attach these weldments together. Referring to  FIGS. 1 and 2 , the weldments that comprise the barrier are base  100 , a pair of uprights  200 , adjustable boom  300 , lower panel support  400 , upper panel support  500 , and panel  600 . Additionally, a misting system  900  may be externally mounted to mobile barrier  10 . Mobile barrier  10  is positioned about a work site (active face  810 ) using heavy machinery  820 . This heavy machinery can include, but is not limited to a variety of machines, from a small machine like a Caterpillar D5 bulldozer, to a large machine like a Caterpillar 836 compactor. Machinery  820  are typically equipped with power lifting components such as a blade  821  or fork (not shown).  
         [0060]     Base  100  is horizontally oriented and supports uprights  200 . Uprights  200  extend generally vertically upward from base  100  and support adjustable boom  300 , lower panel support  400 , and upper panel support  500 . Adjustable boom  300  extends horizontally between the pair of uprights  200 , and is vertically adjustable thereon. Lower panel support  400  is a horizontal member which extends between and is secured to the lower end of each upright  200 . Upper panel support  500  is a horizontal member which extends between and is secured to the upper end of each upright  200 . Lower panel support  400  and upper panel support  500  together support panel  600 . Panel  600  is a rigid planar screen sheet which has a longitudinal edge  602  which lies parallel to base  100 , and a vertical edge  604  which lies parallel to uprights  200 .  
         [0061]     Following are descriptions of each of these weldments and the hardware to attach them together. In all portions of the following description, unless otherwise noted, components which are described as tubes are closed and square in section and have a hollow interior space. Components which are described as channel are provided in an open, U-shape section, the U-shape section having a base portion and two leg portions, the leg portions extending normally from opposed ends of the base portion. Further, references to the front of mobile barrier  10  are directed to the side on which machinery  820  interfaces with mobile barrier  10 , specifically the side on which adjustable boom  300  is positioned. References to the back of mobile barrier  10  are directed to the side opposite the front, specifically the side on which panel  600  is positioned.  
         [0062]     Base  100  is massive, wide, smooth and stable. Its heavy weight, broad stance, and large surface area make it resistant to sinking and tipping in unstable ground. Referring to  FIGS. 1, 3 , and  4 , base  100  consists of main longitudinal tube  110 , transverse foot tubes  120 , brackets  130 , shipping posts  140 , fork pockets  150 , all welded together to form the base weldment.  
         [0063]     Main longitudinal tube  110  is provided in a length which is at least as long as longitudinal edge  602  of panel  600 . Each respective terminal end  111  of main longitudinal tube  110  is angled such that its front surface  118  is shorter in length than its back surface  117 . Tapered ends  111  of main tube  110  provide for positioning multiple barriers adjacent to each other with a few inches of overlap, to prevent litter and wind blowing between barriers. Each respective terminal end  111  is covered by means of main longitudinal tube end plates  112 . Main longitudinal tube end plates  112  are welded to terminal ends  111  to seal them and prevent them from sticking in mud and frozen ground.  
         [0064]     Transverse foot tubes  120  are secured to main longitudinal tube  110 , and are positioned so as to lie transverse to, and in the same plane as, main longitudinal tube  110 . Each transverse foot tube has a first foot tube terminal end  126  which is secured to main longitudinal tube  110 , and a second foot tube terminal end  129  which is opposed to first foot tube terminal end  126 . Second foot tube terminal end  129  is angled such that its upper surface  124  is shorter in length than its lower surface  125 . Foot tubes  120  are provided with angled terminal ends  129  to maximize foot length while allowing machinery  820  to come immediately adjacent to mobile barrier  10  without interference. Second foot tube terminal end  129  is covered by means of transverse foot tube end plate  122 . End plate  122  prevents transverse foot tube  120  from sticking in mud and frozen ground. A pair of transverse foot tubes  120  are welded to main longitudinal tube  110  such that a first foot tube  120  is secured to the back surface  117 , and a second foot tube  120 ′ is secured to the front surface  118  of main longitudinal tube  110 , so that they  120 ,  120 ′ are colinear and oriented transversely to main longitudinal tube  110 . A pair of transverse foot tubes are secured to main longitudinal tube  110  adjacent to, but spaced apart from each terminal end  111 .  
         [0065]     Fork pocket  150  is an elongate sleeve which extends transversely through main longitudinal tube  110  between back surface  117  and front surface  118 . Two fork pockets  150  are positioned within main longitudinal tube  110  between respective transverse foot tubes  120  such that they are equidistant from the center of main longitudinal tube  110 . These sleeves are generally square channels which are sized to receive the fork  821 ′ of machine  820  therethrough for purposes of lifting and repositioning mobile barrier  10 . A lifting lug (not shown) may also be welded to main longitudinal tube  110  to provide additional means of securement to machine  820 . Fork pockets  150  and lifting lugs provide for convenient and safe handling of mobile barriers  10  during on-site positioning and shipping.  
         [0066]     Shipping posts  140  are short angled blocks which extend upward from the upper surface of back-side foot tubes  120  which provide for self-stacking of collapsed and folded multiple barriers for shipping or storage.  
         [0067]     An upright support bracket  130  is used to secure each upright  200  to main longitudinal tube  110  and to maintain upright  200  in a configuration which is generally at a slight angle to the vertical. Upright support bracket  130  also provides a backstop for the bottom of machine blade  821  during lifting and moving. Upright support bracket  130  consists of a pair of opposing side channels  131 , top plates  133 , stacking tabs  134 , and brace channel  135 .  
         [0068]     Side channels  131  are channel in section and and extend vertically upward from main longitudinal tube  110  at the intersection between main longitudinal tube  110  and transverse foot tube  120 . Each side channel  131  is oriented such that the lower edge of its base portion rests on upper surface  114  of main longitudinal tube  110 , and such that the lower edges of its leg portions abut the back surface  117  and front surface  118 , respectively, of main longitudinal tube  110 . The respective base portions of paired side channels  131  are facing each other in a spaced apart relationship.  
         [0069]     Brace channel  135  is channel in section, and shorter in length than side channels  131 . Brace channel  135  is secured between the paired side channels  131  by welding the base portion of each respective side channel  131  to opposed leg portions of brace channel  135 . The lower edge of the base portion of brace channel  135  is welded to main longitudinal tube  110  adjacent to its front surface  118 . Because brace channel  135  is shorter in length than side channels  131 , an opening  136  is provided between the upper portions of side channels  131 . Uprights  200  extend through opening  136  as a result of their slightly angled orientation relative to the vertical. Brace channel  135  is relatively heavy in construction because it is the contact point, or wear surface, for the lower edge of blade  821  of machine  820  when machine  820  is lifting and transporting mobile barrier  10 . Brace channel  135  also provides additional rigidity to upright support brackets  130   
         [0070]     Pin holes  132  are formed in the base portion of each respective side channel  131  such that they are horizontally aligned. Pin holes  132 , when aligned with lower pin holes  212  of upright  200 , receive wrist pins  710  therein to hold upright  200  in place in either erected or folded configuration.  
         [0071]     Top plates  133  and stacking tabs  134  are plate welded to the upper edges of side channels  131 . Top plates  133  add additional structural stiffness to side channel  131 . Stacking tabs  134  are secured to the upper edge of the leg portion of side channel  131 , and allows easy stacking of multiple barriers when mobile barrier  10  is in folded configuration.  
         [0072]     Uprights  200 , together with base  100  and boom  300 , provide for easily lifting, moving and positioning of mobile barrier  10  as site and wind conditions change. In the preferred embodiment, each mobile barrier  10  is provided with two uprights  200 . Referring to  FIGS. 1, 2 ,  5 ,  6 ,  12  and  13 , each upright  200  consist of tube  210 , bottom plate  220 , back plate  230 , and top plate  250 , all welded together to form uprights  200 . Uprights  200  support adjustable boom  300 , lower panel support  400 , and upper panel support  500 , and maintain them in a position which is spaced apart from and overlies base  100 .  
         [0073]     Upright tube  210  is an elongate square tube extending upward from base  130  in an orientation which is generally at a slight angle to the vertical. In the preferred embodiment, this angle is 10 degrees. For purposes of litter control, this angle helps panel  600  shed litter. For example, when mobile barrier  10  is used for litter control, mobile barrier  10  is positioned so that uprights  200  lean into the wind, so that when windspeed drops, any litter trapped upon mobile barrier 10 drops to the ground. For purposes of wind control, panel  600  is positioned to lean downwind. This position reduces the turbulence created by a vertical (oriented at an angle of 0 degrees) panel  600 , and helps to direct wind up and over the barrier. Additionally, providing a slight angle to uprights  200  is a convenient way to extend the adjustable boom  300  over the upper edge of a blade  821  of moving machinery  820 , noting that in such blades  821 , the bottom of the blade is forward of the top of the blade.  
         [0074]     Upright tube  210  has an upper end  260 , a lower end  261 , an back face  262 , a front face  263  which is opposed to back face  262 , and opposing lateral faces  264  which extend between back face  262  and front face  263 .  
         [0075]     Pin holes  211 ,  212  are horizontally aligned through holes extending through lateral faces  264  of upright tube  210 . At least two lower pin holes  212  are provided to position and secure upright  200  to bracket  130  by alignment with pin holes  132  and securement with pins  710 . Multiple upper pin holes  211  provide for adjustment of the height of boom  300 . Upper pin holes  211 , when aligned with pin holes  333  of adjustable boom  300 , receive wrist pins  710  therein to hold adjustable boom  300  at the desired vertical position.  
         [0076]     Back plate  230  is a generally square plate welded to lower end  261  of back face  262  of tube  210  to provide for mounting of lower panel support  400  to upright  200 . Tapped holes  231  are provided in back plate  230 . Tapped holes  231 , when aligned with slotted holes  412  of plate  411  of lower panel support  400 , receive bolts  720  therein to hold lower panel support  400  at the desired horizontal position relative to the lower end of upright  200 .  
         [0077]     A bracket stop may be included to prevent adjustable boom  300  from sliding too far down upright  200  by welding a short plate welded to front face  264  of tube  210 .  
         [0078]     Top plate  250  is generally square plate welded to top of tube  210  to close the upper end  260  of upright  200  and to provide for mounting of upper panel support  500  to the upper end  260  of upright  200 . Tapped holes  251  are provided in top plate  250 . Tapped holes  251 , when aligned with slotted holes  512  of plate  511  of upper panel support  500 , receive bolts  720  therein to hold upper panel support  500  at the desired horizontal position relative to the upper end  260  of upright  200 .  
         [0079]     Bottom plate  220  is a generally square plate welded to bottom of tube  210 . Drain holes (not shown) are provided at the lower end  261  of upright  200  by chamfering the corners of bottom plate  220 . Drain holes provide for drainage of water that may enter upright  220  through pin holes  211 ,  212 . Bottom plate  220  also provides additional rigidity to upright  200 .  
         [0080]     Adjustable Boom  300  provides a means releasably connecting mobile barrier  10  to machinery  820  for purposes of lifting and repositioning mobile barrier. Adjustable boom  300  is vertically adjustable along uprights  200  to accommodate the differing heights of lifting components  821  of machinery  820 . Referring to  FIGS. 5 and 6 , adjustable boom  300  consists of lifting tube  310 , lifting tube sleeves  320 , bale tube  331 , and blade hook  340 .  
         [0081]     Lifting tube  310  is an elongate, horizontally oriented tube which extends between, and is secured to, uprights  200 . Lifting tube  310  has a first end  305 , a second end  306  which is opposed to first end  305  and separated from it by mid portion  304 . Lifting tube  310  has an upper surface  307 , and a lower surface  308  which is opposed to the upper surface and separated from it by the respective front  311  and back  309  surfaces.  
         [0082]     A lifting tube sleeve  320  is provided at each respective end  305 ,  306  of lifting tube  310 . Each lifting tube sleeve  320  is a short tube of square cross section which is sized and oriented to fittingly surround upright  200 , and receive upright  200  through its hollow interior. Lifting sleeve  320  is provided in a length such that its upper edge  324  lies flush with upper surface  307  of lifting tube  310 , and such that its lower edge  325  lies below lower surface  308  of lifting tube  310 .  
         [0083]     Pin holes  322  are horizontally aligned through holes extending through lateral faces  323  of lifting tube sleeve  320  at a position below lifting tube  310 . Pin holes  322  are provided to position and secure lifting tube  310  to upright  200  by alignment with upper pin holes  211  of upright  200  and securement with pins  710 . Multiple upper pin holes  211  provide for adjustment of the vertical position, or elevation, of adjustable boom  300 .  
         [0084]     Bale tube  331  is an elongate tube which fixed to upper surface  307  of lifting tube  310  midway between uprights  200 . Bale tube  331  lies transversely to lifting tube  310  such that it extends perpendicularly relative to front surface  311  of lifting tube  310 . Multiple pin holes  333  provide for adjustment of the transverse position of collar  360  of blade hook  340  along bale tube  331 . Pin holes  333 , when aligned with pin holes  342  of collar  360 , receive wrist pins  710  therein to hold collar  360  at the desired position along bale tube  331 . End plate  332  seals the terminal end of bale tube  331 .  
         [0085]     Blade hook  340  consists of collar  360  and a hook  350 . Collar  360  is a short tube of square cross section which is sized to fittingly surround bale tube  331  and receive bale tube  331  through its hollow interior. Collar  360  has an upper surface  362 , lower surface  366  which is opposed to upper surface  362  and separated from it by lateral sides  364 . Hook  350  is channel in section. Base portion  352  of hook  350  is secured to lower surface  366  of collar  360  so that leg portions  354  of hook  350  are oriented downward and aligned such that they extend between respective lateral sides  364  of collar  360 . A pin hole  342  is provided in horizontal alignment in each lateral side  364  of collar  360 . Pin holes  342  are provided to allow adjustable positioning along and securement to bale tube  331  of collar  360  by alignment with pin holes  333  of bale tube  331  and securement with pins  710 . This adjustment of collar  360  along bale tube  331  allows compensation for machine blades  821  of various sizes and angles. The upper edge of blade  821  of machinery  820  is received within hook  350  when mobile barrier is being lifted and repositioned using machinery  820  ( FIGS. 19 and 20 ).  
         [0086]     Lower Panel Support  400  supports the lower horizontal edge of panel  600 , is provided in a length which is at least as long as longitudinal edge  602  of panel  600 , and is mounted in a horizontal orientation to lower end  261  of upright  200 . Referring to  FIGS. 1, 2 , and  8 , lower panel support  400  consists of brackets  410  and lower panel support member  420 .  
         [0087]     Lower panel support member  420  consists of an elongate tube  421 , front support plates  424 , back support plates  423 , and lateral end support plates  425 . Tube  421  provides most of the support to panel  600 . Lower longitudinal edge  601  of panel  600  is prevented translation relative to tube  421  by employing front  424  and back  423  suppport plates, as well as lateral end support plates  425 . Front  424  and back  423  suppport plates are short flat plates welded to the respective front and back faces of tube  421  at spaced intervals. Front  424 , back  423 , and lateral end support plates  425  are provided in a height which is greater than the height of tube  421 , and are fixed to the respective front, back, and terminal end faces of tube  421  such that they extend above the upper surface of tube  421 , forming a recessed slot into which the lower longitudinal edge  601  of panel  600  resides during use, trapping panel  600  thereon. These plates  423 ,  424 ,  425  also provide rigidity to lower panel support  400 . Tapped holes  422  receive bolts which pass through and secure lower longitudinal edge  602  of panel  600  to tube  421 .  
         [0088]     Lower panel support  400  mounts to back plate  230  of uprights  200  using brackets  410 . Brackets  410  consist of vertically oriented rectangular plate  411  and spacer tube  413 . In use, front face  416  of plate  411  confronts and overlies back plate  230 . Spacer tube  413  is sandwiched between and secured to the lower edges of both the back face  415  of plate  411 , and to front plate  424 . Slotted holes  412 , located adjacent the upper edge of plate  411 , provide compensation for tolerance during assembly of bracket  410  to back plate  230  of upright  200 .  
         [0089]     Upper Panel Support  500  supports the upper portion of panel  600  and provides a means to secure cross tubes  620  of panel  600  to upper end  260  of upright  200 . An elongate tube, upper panel support  500  is provided in a length which is at least as long as longitudinal edge  602  of panel  600 , and is mounted in a horizontal orientation to upper end  260  of upright  200 . Referring to  FIGS. 5 and 7 , upper panel support  500  consists of brackets  510  and upper panel support member  520 .  
         [0090]     Upper panel support member  520  consists of elongate tube  521 , web plates  523 , and studs  529 . Tube  521  has an upper surface  525 , a lower surface  526  which is opposed to upper surface  525 , a front surface  528 , and a back surface  527  which is opposed to front surface  528  and spaced apart from it by respective lower  526  and upper  525  surfaces. Back surface  527  of tube  521  lies parallel to and confronts the front-facing surface of cross tubes  620 .  
         [0091]     Referring now to  FIG. 18 , studs  529  extend outwardly from back surface  527  of tube  521 , and in use pass through an opening  653  in screen  650  and are received within stud slots  621  formed in the lower surface of cross tube  620 . Opening  653  in screen  650  is reinforced by welding a flat, circular plate around the lower peripheral edge of opening  653 . This reinforcement, or “finder”, plate  651 , allows for easy positioning of screen  650  over stud  525  during attachment. Thus, the upper portion of panel  600  is secured to and supported by upper panel support member  520  by being hung upon studs  529 . Additionally, this design locks panel  600  to upper panel support member  520  without the use of tools or adjustment.  
         [0092]     Brackets  510  consist of a horizontally oriented generally rectangular plate  511 , a back edge of plate  511  being secured to a vertically oriented web plate  523 . Bracket  510  is reinforced using a triangular gusset  513  between plate  511  and web plate  523 . Tube  521  is secured to the upper portion of web plates  523 . Slotted holes  512  in plate  511  receive bolts which secure brackets  510 , and thus upper panel support  500 , to top plate  250  of upright  200 . Web plates  523  provide rigidity to upper panel support  500 .  
         [0093]     Referring to  FIGS. 1, 2 , and  9 , panel  600  is an assembly of multiple rectangular sub panels  660 . Multiple sub panels are joined serially at their respective lateral vertical edges  664  to form a single large planar panel  600 . In the preferred embodiment, panel  600  is formed of four sub panels  660  as illustrated in the figures. However, it is well within the scope of the invention to provide panel  600  having more or fewer sub panels  660  in order to accommodate the requirements of a specific application.  
         [0094]     Each sub panel  660  is formed of perimeter tubes  630 , lifting tube  610 , cross tubes  620 , stacking tabs  640 , and screen  650 . Perimeter tubes  630  consist of four sections of tube which provide a rectangular outer frame having opposed long vertical edges  664 , and opposed short horizontal edges  662 . Opposing vertical edges  664  are bridged using at least two horizontally oriented cross tubes  620 . A lifting tube extends vertically between each adjacent cross tube  620 , and is positioned mid way between the vertical edges  664 . Lifting tube  610  is heavier than cross tubes  620  and cross tubes  620  are heavier than perimeter tubes  630 . Lifting tube  610  provides for lifting and handling multiple panels  600  with a forklift without damage to delicate panels  600 .  
         [0095]     Cross tubes  620  transfer lifting load to perimeter tubes  630 . In addition, the lower surface of cross tube  620  have t-shaped stud slots  621  formed therein which are sized and shaped to receive the studs  529  of upper panel support  500  therein ( FIG. 18 ).  
         [0096]     Lifting tubes  610 , cross tubes  620 , and perimeter tubes  630  provide a very strong, lightweight frame on which to mount relatively fragile screen  650 . Screen  650  is welded to cross tubes  620  and perimeter tubes  630 . The panels  600  are planar and free of catches that would tend to trap litter against the panels. The panels  600  are detachable and interchangeable, so a barrier  10  may be used with panels having generally “closed” screen downwind to control wind, or used with panels having generally “open” screen back to control litter. In the preferred emobidment, open screen  650  ( FIG. 10 ), used to control litter, is 1.5″×13 ga. flattened expanded steel with an open area of approximately 83 percent. Also in the preferred embodiment, closed screen  650 ′ ( FIG. 11 ), used to control wind, is 16-gage perforated steel with an open area of approximately 50 percent, preferrably in the range of 40 to 60 percent.  
         [0000]     Misting System  
         [0097]     Mobile barrier  10  may be provided with a misting system  900  ( FIGS. 16 and 17 ) for use in controlling the suspension and transport of airborne contaminants from earthwork, landfill, and surface mining operations. Misting system  900  is externally mounted to mobile barrier  10 , and includes a power unit  930 , fluid tanks  940 , fluid pump  920 , spray bars  910 , and interchangeable nozzles  914 . Base  100  of mobile barrier  10  provides a rugged platform for the tanks  940 , power unit  930 , pumps  920 , and associated controls and plumbing so that the misting system is mobile. In the preferred embodiment, when mobile barrier  10  is provided with misting system  900 , it is used with panels  600  having closed screen. This allows wind reduction to be combined with the misting action for more effective contaminant control.  
         [0098]     The power unit  930  provides mechanical power to the pump  920 . Power units are conventional and well known in the art. In the preferred embodiment, power unit  930  includes a diesel motor with an electric start, such as the commercially available Hatz 5-hp 1B40 industrial diesel motor. Diesel power is preferred because it has better fire safety than gas, is more efficient because it consumes less fuel, and is the fuel of choice for that machines that will be used with the misting system. Additionally, the diesel motor is more amenable to automation and control because it is easier to provide remotely controlled start, stop, and throttle. It is understood, however, that other motors may be substituted to suit the requirements of a specific application. Pumps  920  are also conventional and well known in the art. In the preferred embodiment pump  920  is a triplex progressive cavity pump capable of producing pressures of at least 2000 psi, such as the GP brand pump for a pressure washer. It is understood, however, that other pumps may be substituted to suit the requirements of a specific application. Pump  920  is directly coupled to power unit  930 .  
         [0099]     Tanks  940  provide water for the misting system. Tanks  940  are selected to provide optimum water capacity. High water capacity is important because it increases the autonomy time of the misting system  900 . However the high water capacity is balanced with the load carrying capability of the mobile barrier. Thus, tanks  940  provide the optimum capacity, but also partition the water, as in the case of fuel tanks for aircraft, for example. Partitioning may be accomplished by using plural, serially connected tanks  940  as shown in the figures, or by other conventional means. A series of check valves are provided between tanks  940  to prevent water from flowing from one tank to the other. This prevents shifting of the water on uneven terrain that would produce an unbalanced load that is difficult to handle.  
         [0100]     Plumbing allows fluid flow between tanks  940 , pump  920 , and spray bars  910 , and consists of low pressure piping, check valves, an inlet screen to protect the pump, high pressure piping, a pressure regulator, a relief valve, gages, and all other necessary valves and fittings.  
         [0101]     Spray bars  910  are a manifold of machined nylon pipe  912  that provide water pressure to plural, spaced apart nozzles  914 . Spray bars  910  are built to withstand pressures up to 2000 psi. Nozzles  914  are selectively removable and interchangeable to provide the required water droplet size distribution. In the preferred embodiment, nozzles  914  are spaced one nozzle per foot along spray bar  910 .  
         [0102]     Many misting sytems are left on, even when they are not needed, because startup and shutdown is an inconvenience to the operators. This practice wastes water and creates a mess. Misting system  900  features controls that address this problem. The controls allow an operator to remotely start, stop, and vary the output of the misting system from the cab of the machine. Therefore the appropriate mist can be dispensed as needs change. This reduces water and fuel consumption and increases autonomy time because it reduces service interval to fill water and fuel.  
         [0103]     A wind speed and direction indicator may be mounted on top of panels  600 . The preferred indicator consists of a wind vane, pinwheel, and gimball mount. This wind speed and direction indicator would provide visual indication of relative wind speed and direction in the area of the barrier. With this information the operator can position the barrier in the optimum location. Use of a gimbal mount provides vertical orientation of axis when barrier  10  is positioned on uneven terrain.  
         [0104]     Approximate dimensions for the components used to form the preferred embodiment of my invention will now be provided. It is understood, however, that these approximate dimensions are provided for purposes of illustration of scale and construction of the invention, and that these approximate dimensions may be altered to accommodate the requirements of a specific application. Specific fabrication and welding methods, and clearances, dimensions, and tolerances are not included in this specification because they are within ordinary skills in the art of steel fabrication.  
         [0105]     In the preferred embodiment, mobile barrier  10  is 8 feet deep, 20 feet long, and approximately 13 feet tall. Main longitudinal tube  110  is formed of an 8″×8″× 1/4″ tube of 20 feet in length, and main longitudinal tube end plates  112  are formed from 1/4″ plate welded to terminal ends  111 . Each transverse foot tube  120 ,  120 ′ are 8″×8″× 1/4″ tube of approximately 4 feet in length, providing an overall transverse footprint of approximately 8 feet. Foot tube end plates  122  are 1/4″ plate welded to ends of tubes  121 .  
         [0106]     Side channels  131  of upright support brackets  130  are 8″×13.75# channel. Top plates  133  and stacking tabs  134  are 1/4″ plate welded to side channels  131 . Front plate  135  is 8″×13.75# channel welded between side channels  131 .  
         [0107]     As regards uprights  200 , upright tube  210  is 8″×8″× 1/4″ tube of approximately 8 feet in length. In the preferred emobdiment two uprights  200  are provided on mobile barrier  10 , spaced on center approximately 10 feet apart.  
         [0108]     Adjustable boom  300  has an overall length of approximately 10 feet. Lifting tube  310  is formed of an 8″×8″× 1/4″ tube, and lifting tube sleeves are formed of 3/8″ steel plate. Lifting bale  330  is welded to the front center of lifting tube  331  and consists of 8″×8″× 1/4″×16″ tube.  
         [0109]     As regards lower  400  and upper  500  panel supports, respective support tubes  421 ,  521  and spacer tube  521  are formed of is 2″×2″× 1/4″ tube.  
         [0110]     As regards panels  600 , lifting tube  610 , cross tubes  620 , and perimeter tubes  630  are all 2″×2″ tube, having 1/4″, 1/8″, and 1/16″ thicknesses, respectively. In the preferred embodiment, panels  600  have overall dimension of 5′×12′×2″. Screen  650  is either open, having 1.5″×13 ga. expanded flattened steel of 83 percent open area ( FIG. 10 ), or closed, having 16 ga. perforated steel with approximately 50 percent open area ( FIG. 11 ).  
         [0111]     Referring to  FIGS. 14 and 15 , the mobile barrier folds very compactly and multiple barriers stack securely for efficient and safe shipping. To accomplish this, panels  600  and panel supports  400 ,  500  are dis-assembled, and the uprights  200  and adjustable boom  300  are folded relative to base  100 . Panel supports  400 ,  500  are self locking and stowing such that no tying-down or taping is required to keep them stacked with the folded unit. The aforementioned stacking tabs  134  on upright support brackets  130  and shipping posts  140  on foot tubes  120  provide for stacking with no blocking, bracing, cribbing. These provisions allow for up to six units to be shipped on a standard 8′×40′ flatbed trailer.  
         [0112]      FIG. 20  shows barrier  10  as it is being moved around active face  810  of a site with blade  821  of bulldozer  820 . The top of blade  821  fits inside hook  350  of adjustable boom  300 . The bottom of blade  821  rests against front plate  135  of base brackets  130  of base  100 . This configuration provides for securely lifting and moving the barrier around the active face.  
         [0113]     In  FIG. 20  wind direction is indicated by an arrow to be flowing from the upper left to lower right. Several mobile barriers  10  are placed downwind  830  of an active face  810  using panels  600  which would be equipped with open screen  650  to prevent litter from escaping from active face  810 . The bulldozer  820  places the barriers  10  immediately downwind  830 , and at the actual edge, of the active face  810  forming a downwind barrier  850 . The barrier  850  stops the litter as the wind passes through. When the wind subsides, the litter falls down to the base of the barrier and is still within active face  810 .  
         [0114]      FIG. 20  also shows several mobile barriers  10  placed upwind  840  of active face  810  forming an upwind barrier  860  to control wind, thereby reducing suspension and transport of airborne contaminants from active face  810 . The bulldozer  820  places the barriers immediately upwind  840  of the active face  810 . These barriers would be equipped with closed screen material which allows approximately  50  percent of the wind to pass through, thereby reducing wind speed without creating turbulence. If desired, misting system  900  could be employed on upwind barrier  860 .  
         [0115]     I also anticipate that the mobile barrier may be useful for control of wind in agriculture, erosion control, and snow control. In view of the foregoing discussion such use would be obvious to persons with ordinary skills in these fields.  
         [0116]     While my above description contains many specificities, these should not be construed as limitations on the scope of the invention, but rather as an exemplification of one preferred embodiment thereof Many other variations are possible and are understood by those skilled in the art.