Abstract:
An air filter arrangement for use in a truck pneumatic product transfer system using a generally rectangular housing and two air filter cartridges to alter the shape thereof (primarily reduce the width thereof) allowing the unit to be mounted centrally behind a truck cab or in other locations. The design and shape allows mounting on the truck in preferred areas that are less utilized for accessory equipment and can increase truck aerodynamics. Additionally the filter arrangement can reduce overall truck weight compared to traditional units.

Description:
[0001]    This application claims priority from U.S. Provisional Application Ser. No. 62/024,752 entitled “FILTER SYSTEM” and filed on Jul. 15, 2014. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present application relates to an air filter structure typically used as part of a pneumatic transfer system used by trucks to transfer dry bulk goods. In particular, the invention relates to an improved air filter structure used to filter air blower intake air. 
       BACKGROUND OF THE INVENTION 
       [0003]    Transport type trailers designed for hauling dry bulk goods commonly include a pneumatic loading and off-loading system. The pneumatic system includes an air pump/blower and an air filter unit that are mounted on the outside of a frame rail of the truck tractor unit. Typically, the pump/blower includes a cooperating large diameter cylindrical air filter housing that provides filtered intake air to the pump/blower. 
         [0004]    These truck pump/blowers are offered by a number of different manufacturers and are mounted on L-shaped brackets secured to an outside surface of a frame rail of the tractor. In some cases the pump/blower is mounted to the exterior of the frame rail on one side of the tractor and the filter unit is mounted on an opposite side of the tractor on the other frame rail. In some installations both the pump/blower and the filter housing are located on the same side of the tractor. The filter housing is typically a large cylindrical unit with air passing generally vertically through the filter unit. 
         [0005]    Typically the pump/blower and the filter housing are positioned to overlap with the respective frame rail. 
         [0006]    With tractor trailers, the amount of equipment carried by the tractor continues to increase and available mounting space has become limited. For example, wind panels or wind deflectors are often mounted to the frame rails of the tractor to improve fuel efficiency and fuel additive tanks are mounted on the outside of the frame rails and/or behind the tractor cab. In contrast to the traditional cylindrical filter unit having a large cylindrical filter cartridge housed therein, the present invention utilizes a different arrangement that is narrow in profile, non-circular, and designed to be more effectively mounted with the other equipment carried on a tractor trailer. 
       SUMMARY OF THE INVENTION 
       [0007]    An air filter structure according to the present invention is used as part of a truck mounted pneumatic transfer system for dry bulk material. The air filter structure comprises an elongate housing and a removable cover. The removable cover is oversized relative to an upper support edge of the elongate housing and defines an air inlet between an upper edge of the housing and the removable cover. The air filter structure includes two removable air filters secured in a cavity of the housing and spaced in a length of the elongate housing with each air filter having an air outlet. The air filters cooperate with the elongate housing and the single air outlet port to define an air flow path between the air inlet and the air outlet port that passes through the air filters. 
         [0008]    According to an aspect of the invention, the elongate housing includes a separating member traversing the elongate housing and forming an air outlet plenum in the elongate housing located below the separating member. The separating member includes two air filter mount arrangements located above air filter ports opening to the air outlet plenum. The air outlet port is located in the elongate housing and associated with the air outlet plenum and allows filtered air to pass out of the air outlet plenum. 
         [0009]    In an aspect of the invention, the elongate housing is generally rectangular in shape having a depth of 10 to 12 inches, a length of 20 to 24 inches and of a height of at least about 17 inches. 
         [0010]    According to a further aspect of the invention, the elongate housing and the removable cover are fabricated of a structural plate material capable of supporting a person&#39;s weight when standing on top of the lid allowing the air filter structure to act as support surface. Preferably the structural plate is made of an aluminum material. 
         [0011]    In an aspect of the invention, rubber tension fasteners releasably secure the lid to the elongate housing. The rubber tension fasteners maintain the lid in an operating position covering the elongate housing. 
         [0012]    According to an aspect of the invention, the lid includes a series of downwardly extending flanges positioned to cooperate with the upper edge of the elongate housing to align the removable cover in an operative position engaging the walls of the elongate housing. 
         [0013]    In a further aspect of the invention, the downwardly extending flanges engage exterior surfaces of the elongate housing adjacent the upper edge. 
         [0014]    In a different aspect of the invention, the removable cover includes an outer hood of a metal plate material, the outer hood includes a support plate secured to the outer hood. The support plate has a lip portion covering the upper edge of the elongate housing and extends inwardly of the upper edge. The support plate includes an elongate central port with an upwardly extending screen member positioned about the central port and structurally connecting the outer hood and the support plate. The screen member, the outer hood and the support plate cooperate to define an airflow path between an open gap between the outer hood and the elongate housing, through the screen member and into the elongate housing. Preferably, the support plate along a side edge includes an upwardly extending flange mechanically secured to a downwardly extending portion of said outer hood and forming a load transfer surface with a first side upper edge of said elongate housing. Preferably, the support plate includes a second side edge parallel to the first side edge. The support plate at the second side edge includes a series of space brackets connected to a downwardly extending side flange of the outer hood with an air inlet defined between the side flange of the outer hood and the support plate. 
         [0015]    In yet a further embodiment of the invention, the air filters are mounted on an upper surface of an air outlet plenum and a downwardly extending air outlet port is located in a base portion of the elongate housing. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS  
         [0016]    Preferred embodiments of the invention are shown in the drawings, wherein: 
           [0017]      FIG. 1  is a side view of a truck tractor with the air filter structure located behind the cab; 
           [0018]      FIG. 2  is a top view of the truck tractor showing the air filer structure centrally located behind the tractor cab; 
           [0019]      FIG. 3  is an exploded perspective view of the air filter structure and the various components; 
           [0020]      FIG. 4  is a partial exploded view showing interior components of the filter housing and the mounting of filter units; 
           [0021]      FIG. 5  is a partial cut-away of the assembled filtered housing with the filter units not shown for clarity; 
           [0022]      FIG. 6  is a cross-sectional view through the air filter structure showing the air flow; 
           [0023]      FIG. 7  is an end view of the air filter structure showing the releasable hood securement; and 
           [0024]      FIG. 8  is a rear perspective view of the air filter structure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0025]      FIG. 1  shows the truck tractor  2  and the relative positions of the cab  4 , a fuel tank  6  an air blower  8 , a side rail  9  of the truck tractor, and the position of the air filter unit centrally behind the rear face of the cab. The top view of  FIG. 2  shows the relative position of these components. It can be seen in the top view of  FIG. 2  that the truck tractor  2  includes opposed side rails  9  as well as a central drive shaft  11 . 
         [0026]    The preferred positioning of the filter unit  10  behind the rear face of the cab  4  and generally centrally with respect to the width of the truck tractor is advantageous as the space immediately exterior of the side rails  9  is commonly used to mount a diverse arrangement of accessory components. For example, wind panels or wind deflectors are often mounted to the side rails  9  to improve fuel efficiency. Fuel additive tanks are mounted on the outside of the frame rails. 
         [0027]    Traditional filter units for air blowers are of a cylindrical design. These traditional filter units have a large cylindrical cartridge housed therein and there is insufficient room to mount this type of filter unit behind the cab. These cylindrical filter units and air blowers are mounted to the exterior of the side rails (negatively impacting aerodynamics) and compete with many other components that are needed or commonly added to a truck tractor. 
         [0028]    The design of the filter housing  10  and its suitability for mounting centrally behind the cab  4  (due to the elongate shape thereof) allows the air filter structure to be mounted in an area that is less frequently used and allows other components to be mounted to the exterior of the side rails. Although the central mounting location is preferred, the air filter unit can be mounted in traditional locations. 
         [0029]    The air filter structure as will be further described is also designed to be placed in close proximity to the rear face of the cab while still allowing the cab and components associated therewith to be serviced. This protected position is more fuel efficient (does not negatively impact aerodynamic factors) and the filter housing is preferably made of a light weight material, such as aluminum to reduce the overall weight. 
         [0030]    The filter unit  10  is used to filter air that is provided to the blower unit  8  as part of the truck pneumatic offloading system. The blower unit is typically secured to the exterior of one of the side rails  9  and includes a power input arrangement powered by the truck tractor. The filter unit  10 , as will be further described, includes an output port  14  for connection to the blower unit  8  and straddles the frame rails  8  simplifying securement and reducing weight due to the simplified mounting structure. 
         [0031]    As shown in  FIG. 3 , the filter unit  10  includes the filter housing  12  having mounted therein replaceable filter cartridges  24  and  26 . Each of these filter cartridges include a top plate  25  and  27  respectively. These top plates are sometimes an integrated fixed component of the filter cartridge. A number of different arrangements can be provided for holding of the filter cartridges in place. These filter cartridges are supported on a false bottom identified as  28 . With this arrangement air in the outlet plenum  30  passes out of the filter unit  10  and out to the blower unit through the outlet port  14 . 
         [0032]    The filter unit  10  includes the removable cover  16  made up of the hood  18 , the screen filter ring  20  and the support bracket  22 . Components  18  through  22  are preferably mechanically secured together to form an integrated component. The support bracket  22  includes three brackets  23  that mechanically connect the support bracket  22  to a side edge of the hood  18 . With this arrangement the hood is mechanically attached to the support bracket on opposite sides of the filter unit  10 . The top surface of the hood  18  is preferably textured and made of an aluminum material. With this arrangement the top surface of the hood forms a raised support surface behind the truck cab. 
         [0033]    In the exploded view of  FIG. 4  the housing  12  has been removed to show the assembly of the replaceable filter cartridges  24  and  26  in the filter unit  10 . The filter cartridge  24  can be inserted on the pedestal mount  32  which includes a projecting threaded rod  34 . The threaded rod  34  cooperates with the top plate  25  and the wing nut  36  to secure the cartridge against the false bottom  28 . There is a circular port  38  in the false bottom  28  and this port opens into the outlet plenum  30  in the base of the housing. A similar arrangement is provided with respect to the replaceable filter cartridge  26 . In his way air can pass through each of the filter cartridges  24  and  26  and enter the outlet plenum  30  and eventually pass out the outlet port  14 . 
         [0034]    In  FIG. 5  it can be seen that the lid cover  16  is over sized on three of the sides to project beyond the side and end faces of the filter housing. In this way air can pass between the removable cover  16  through the screen filter ring  20  and into the filter housing  12 . Thus the screen filter ring provides a first filtering of the air. This air has already been diverted from a generally upward direction to a horizontal direction and downwards. This will assist in separation of any material in the air. 
         [0035]    It is preferable that the hood  18  not project or not appreciably project beyond one side face of the filter housing  12 . Basically the side face of the removable cover  16  is essentially aligned with the front surface of the filter housing. The end view of  FIG. 6  illustrates this arrangement and principle. 
         [0036]    With this arrangement air can pass upwardly into the removable cover  16  through the screen filter ring  20  and pass downwardly into the filter housing  12 . The filter cartridges are supported in the filter housing  12  and air can then pass through those filter cartridges providing filtered air for the blower unit  8 . 
         [0037]    With this arrangement the filter unit is provided with two replaceable filter cartridges  24  and  26  allowing the filter unit to be of a generally rectangular configuration and located across the rails of the truck tractor in a generally central location. The use of two filters allows each filter to be of a significantly reduced diameter relative to the larder diameter and height of the single filter cartridge used in existing systems. 
         [0038]    In  FIG. 6  it can be seen that air passes through a gap between the removable cover  16  and the filter housing  12  and then passes downwardly before being presented to the replaceable filter cartridges. Air can pass through the filter cartridges and is discharged centrally of the filter cartridge into the air output plenum  30 . The air output plenum  30  is appropriately connected to the blower unit via an outlet port  14 . 
         [0039]    The screen filter ring  20  not only provides an initial coarse filtering of air, it also provides a mechanical structural member spacing the hood cover  18  from the support bracket  22 . When a person stands on the hood cover  18  some of the load is transferred through the screen filter ring  20  to the support bracket  22  and to the top edges of the filter housing  12 . The replaceable air filter cartridges are located below the upper edge of the filter housing  12 . 
         [0040]      FIG. 7  shows a preferred elastic type tensioning member used to secure the hood  16  to the filter housing  12 . The hood  16  carries a rubber elastic member  46  that is stretched and locked below a fixed latch  60 . This fixed latch is secured to the filter housing  12 . In this way a tensioning force is maintained on the hood  16  to maintain its position covering and effectively protecting the filter housing  12 . Additional details of the latch can be seen in  FIG. 5 . As shown, the fixed latch  60  is mounted on the side of the housing and the elastic member  46  engages and is retained on. This type of connection is often used with respect to truck hoods and other components. It maintains tension and provides reliable releasable securement. Other releasable securing mechanisms can be used. 
         [0041]    Preferably, the filter housing is generally rectilinear in shape with a depth of about 12 inches, a length of less than 24 inches (preferably 22 inches) and a height of 20 inches or less. 
         [0042]    The filter unit can also filter air provided to a pump unit with some adaption to allow a pump suction to connect to the bulk storage container on the trailer to assist in dry bulk material loading. 
         [0043]      FIG. 8  is a rear perspective view of the filter unit  10  showing the relationship of the filter housing  12  and the hood  16 . 
         [0044]    Although various preferred embodiments of the present invention have been described herein in detail, it will be appreciated by those skilled in the art, that variations may be made thereto without departing from the scope of the appended claims.