Abstract:
A liquid chemical applicator tank made out of ultrahigh modular weight polyethylene which has a higher volume tank by use of a tank design with a narrower front end and wider rear end over the wheels of the trailer. The tank has wheel wells over the wheels, and a series of weldments on the frame engage indented ribs in the tank to help support the tank over the wheels. The tank has a short length and width while having a large volume such that the width is less than twelve feet, eliminating special road permits, while hauling up to 2400 gallons with a 62½ inches on-center lateral length between the inside wheel assemblies. The short length and low profile allows better tracking and greater visibility. Indented ribs in the tank engage weldments on the trailer frame to eliminate straps to hold the tank on the trailer.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention relates to agricultural trailed equipment used in the application of liquid chemicals and more particularly to a plastic liquid chemical tank to increase the capacity of the applicator and, at the same time, maintain a short coupled low profile trailer for better tracking and visibility. 
   2. Description of the Prior Art 
   Agricultural trailed chemical application equipment generally consists of a rolling framework that supports a reservoir to carry liquid chemical product. The product contained in the reservoir is delivered to various locations along a boom mounted to the framework for accurately dispensing at a desired latitudinal distance from the centerline of the main trailer towing vehicle or tractor. The trailer is attached to the tractor through a load bearing pivot point at the rear of the tractor which allows the tractor-trailer combination to articulate for steering purposes. 
   The economy of chemical application is continuously improving by increasing the latitudinal distance, swath width, of the application equipment in an effort reduce the number of passes required for a given area of land. In addition to increasing the boom lengths, larger liquid chemical tank capacities are also desired to reduce the number of reloading operations that are required. As agricultural semi-trailed chemical application equipment has grown larger in size the accepted practice of increasing the liquid chemical tank&#39;s capacity is to retain a generally rectangular or elliptical profile and lengthen and/or raise the overall height of the tank. The lateral dimension of the tank is usually limited by Department of Transportation (D.O.T.) regulations which do not allow shipping or hauling of equipment more than twelve feet (3.66 meters) in overall width without special road permits. Lengthening the liquid chemical tank also in effect lengthens the trailer, thereby moving the rear mounted boom and axle arrangement back away from the towing vehicle. The axle assembly must move proportionally with the lengthened tank in order to maintain a proper balance of the trailer unit to the hitch point, thereby minimizing or eliminating the reverse gravitational hitch loads. 
   Increasing the distance between the tractor hitch pin and the trailer&#39;s axle, however, reduces the trailer&#39;s ability to effectively follow in the same wheel track as the towing vehicle. This off-tracking is a common characteristic of fixed axle semi-trailed equipment whenever the refraction angle at the hitch point deviates from an aligned position such as when turning or steering corrections are necessary. Wheel off-tracking is also exaggerated on trailing equipment when traversing a side slope where the gravitational force tends to pull or slide the trailer down the slope causing the trailer to yaw from an optimal path in which the center line of the trailer is aligned simultaneously with the centerline of the towing vehicle. Whether the result of side slopes or necessary navigating functions, whenever the trailer&#39;s wheel path deviates from the tractors wheel track, there is a substantial risk of increased crop damage and loss of overall yield. 
   Increasing the overall height of the tank to obtain more tank capacity greatly raises the center of gravity and obstructs rear view. Raising the center of gravity causes the trailer assembly to become less stable and more susceptible to roll over. 
   Typically a plastic liquid chemical tank is secured to the trailer framework by means of nylon straps or a formed steel members that circumnavigate the tank and bolt to the trailer frame work. As well as securing the tank to the trailer&#39;s framework the formed steel members, or “hoops”, can also provide structural integrity to the plastic tank and help maintain the original rectangular or elliptical profile. 
   SUMMARY OF THE INVENTION 
   The wedge shaped profile of the invention&#39;s plastic liquid chemical tank provides a high volume configuration, from 1800 gallons to 2400 gallons, that more effectively uses the available space on an agricultural pull type sprayer. Effectively using space that would normally be void with other traditional tank profiles provides a means of maximizing the volumetric capacity while maintaining a relatively short length and low height tank profile. Minimizing the length of the liquid chemical tank allows the trailer to be short coupled to the towing vehicle and reduces the amount of off-tracking that may occur while turning corners or crossing side slopes. Furthermore an overall minimum height profile will increase the operator&#39;s rearward visibility while also reducing the tendency for the trailer to overturn on steep terrain. 
   In place of the commonly used straps or formed steel members to fasten the tank to the trailer, the invention&#39;s tank profile has recessed pockets molded into it that allows the tank to be secured to the trailer through a bolted UHMW tab. This tab and slot method greatly reduces both the material and labor cost associated with securing the tank to the trailer. 
   OBJECTS OF THE INVENTION 
   It is an object of the invention to enhance the tracking performance of the applicator trailer relative to the towing vehicle. 
   It is an object of the invention to minimize the distance from the towing vehicle to the axle or axles of the trailer. 
   It is an object of the invention to maximize the liquid chemical tank&#39;s volumetric capacity relative to the distance from the towing vehicle to the axle or axles of the trailing chemical applicator. 
   It is an object of the invention to maximize the liquid chemical tank&#39;s volumetric capacity relative the overall transport height, and width of the trailing chemical applicator. 
   It is an object of the invention to maximize rearward visibility relative to the volumetric capacity of the liquid chemical tank. 
   It is an object of the invention to provide a high capacity liquid chemical tank for trailing chemical applicators that will not exceed twelve feet (3.66 meters) in overall transport width. 
   It is an object of the invention to provide a trailing chemical applicator with a minimum 62½ inch (1.59 meters) on-center lateral dimension between the single wheel assemblies 
   It is an object of the invention to provide a trailing chemical applicator with a dual wheel arrangement to accommodate 62½ inches on-center lateral dimension between the two inside wheel assemblies and 120 inches (3.05 meters) lateral on-center dimension between the two outside wheel assemblies. 
   It is the object of the invention to allow a 167 inch (4.24 meters) longitudinal distance between the center of the chemical applicator&#39;s wheel assembly and the center of the hitch point. 
   It is an object of the invention to maintain a positive load in the direction of gravitational force at the coupling connection between trailer and towing vehicle. 
   It is the object of the invention to provide a simple and effective means of securing a plastic tank to the trailer&#39;s metal framework without using hoops or straps. 
   It is the object of the invention to access the fill port of the chemical tank by means of the operator&#39;s platform with the wings folded in the transport position. 
   It is the object of the invention to have a liquid chemical tank capacity of more than 1800 gallons. 
   Other objects, advantages, and novel features of the present invention will become apparent from the following description of the preferred embodiments when considered in conjunction with the accompanying drawings and illustrations. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a preferred embodiment of an agricultural sprayer assembly constructed in accordance with the present invention with the booms unfolded in the field application position; 
       FIG. 2  is a perspective view of the preferred embodiment of  FIG. 1  with the booms folded in as in a transport position; 
       FIG. 2A  is a side plan view of the agricultural sprayer assembly of  FIG. 2  with the booms folded in as in a transport position; 
       FIG. 2B  is a top plan view of the agricultural sprayer assembly of  FIG. 2  with the booms folded in as in a transport position 
       FIG. 3  is a partial exploded view illustrating the means by which the liquid chemical tank is secured to the trailer frame assembly; 
       FIG. 4  is a perspective view of components that, in part, form the carrier frame assembly used with the configuration of  FIG. 1 ; 
       FIG. 4A  is a partial cross-sectional view of the carrier frame assembly illustrated in  FIG. 4 ; 
       FIG. 4B  is a detailed perspective view of the side wall brace used on the carrier frame illustrated in  FIG. 4 ; 
       FIG. 4C  is a detailed perspective view of the rear fender support used on the carrier frame illustrated in  FIG. 4 ; 
       FIG. 4D  is a detailed perspective view of the middle fender support used on the carrier frame illustrated in  FIG. 4 ; 
       FIG. 4E  is a detailed perspective view of the front fender support used on the carrier frame illustrated in  FIG. 4 ; 
       FIG. 4F  is a partial rear perspective view of the carrier frame used with the configuration of  FIG. 1 ; 
       FIG. 4G  is a detailed perspective view of the transport rack used on the carrier frame illustrated in  FIG. 1 ; 
       FIG. 5  is a partial exploded view of the preferred agricultural sprayer assembly shown illustrated in  FIG. 1 ; 
       FIG. 6  is a top plan view of the invention&#39;s liquid chemical tank of  FIG. 1 ; 
       FIG. 7  is a lower perspective view of the liquid chemical tank illustrated in  FIG. 1 ; 
       FIG. 8  is a cross-sectional view of the liquid chemical tank and carrier frame illustrating the interior baffle components and carrier frame and tank support features. 
       FIG. 9  is a perspective rear perspective view of the liquid chemical tank illustrated in  FIG. 1 ; 
       FIG. 10  is a left side plan view of the liquid chemical tank illustrated in  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   Chemical applicator trailers, or more specifically, agricultural trailer sprayer assemblies, made in accordance with the present invention all have various features in common. The first such feature shown in  FIG. 1  is the carrier frame assembly  11 . As its label implies, the carrier frame  11  is configured to facilitate the transporting or carrying of other sprayer assembly  1  components such as the chemical reservoir  2 , clean rinse water reservoir  5 , clean water hand/eye wash reservoir  6  and the chemical application boom  4 . The carrier frame  11  is partially supported by a rolling assembly which may consist of but is not limited to a wheel or wheeled assemblies  7 . The remaining resultant forces are typically supported by a rigid hitch assembly  45  that protrudes from the front of the carrier frame  11  and is connected to a tractor or other powered vehicle in a conventional manner. The chemical tank  2  stores a liquid mixture to be evenly applied to the ground or foliage through multiple distribution points located along the chemical application boom  4 . Additionally  FIG. 1  illustrates a clean water rinse tank reservoir  5  used to flush residual chemicals from the tank  2  or subsequent plumbing to the distribution nozzles along the application boom  4 . A separate small volume hand/eye wash reservoir  6  is mounted to the carrier frame  11  and provides clean water for use as a limited personal wash station. 
   Those skilled in the art will immediately recognize that an agricultural sprayer must maintain a high clearance between the underside of the trailer assembly and the ground to maximize crop clearance. Furthermore it is advantageous to minimize the longitudinal distance between the towing vehicle&#39;s hitch point and the wheel assemblies  7  of the trailer sprayer to minimize off-tracking and prevent crop damage. For stability and visibility reasons it is also desirable to maintain a relatively low overall height profile. 
   The present invention generally resides in the liquid chemical tank&#39;s  2  shape, the manner in which it is supported by and secured to the carrier frame assembly  11 , and more specifically how it allows for a balanced short coupled low profile trailer sprayer. For this reason, the prior, exemplary trailer sprayer assembly, application boom  4 , rinse tank  5 , and hand/eye wash reservoir  6  are described in minimal detail and hereinafter the liquid chemical tank  2  and carrier frame  11  will be described in greater detail. 
     FIG. 2  and  FIG. 2B  illustrate the wedge shape design of the tank  2  relative to a top plan view and how the profile of the tank  2  is designed to fit into the available cavity created when the boom assembly  4  is folded forward into the transport position. 
   Referring to  FIG. 3 , the method of securing the chemical reservoir  2  to the carrier frame  11  is via a UHMW hold down tab  10  in conjunction with a bolt  8  and washer  9  on each side of the agricultural trailer sprayer. 
   As shown in  FIG. 4 , the frame assembly  11  has various components located for attachment and support purposes relative to the overall function of the trailer sprayer as a whole. The function or purpose of each component associated to the invention should become clear as the carrier frame  11  and reservoir tank  2  are explained in further detail. 
   Among the many components shown on the carrier frame assembly  11  in  FIG. 4 , a hitch assembly  45  projects from the front of the frame and is the primary member for mounting the components which make up the exemplary hitch assembly for securing the trailer to the towing vehicle. 
   The primary boxed framework of the carrier frame  11  shown in  FIG. 4 , has two rectangular side tubes  12  that run longitudinally on the outside edge of the carrier frame  11  and are joined at each end by a front lateral cross member  13  and lower rear lateral cross member  14 . Interior square tube members  15  run inside the boxed frame parallel to the rectangular side tubes  12  between the front cross member  13  and the lower rear cross member  14 . As shown in the cross sectional view of  FIG. 4A , this interior longitudinal square tube  15  is preferably tipped slightly relative to the face of the parallel rectangular side tube  12  to match the incline of the of the chemical reservoir&#39;s floor. 
   Referring to  FIG. 4  and  FIG. 4A , a formed intermediate cross member  16  ties the inside square tubes  15  to the outside rectangular tubing  12  and also provides a flat surface to support the floor of the liquid chemical tank  2  at this point. Because the formed intermediate cross member  16  supports a large portion of the liquid chemical tank&#39;s  2  overall loaded weight, a profile gusset  24  is used to reinforce the intermediate cross member&#39;s adhesion to the two longitudinal rectangular side tubes  12 . Appropriately formed channel members  17  are positioned on the tipped interior square tubes  15  between the front cross member  13  and the formed intermediate cross member  16  to provide additional flat area to rest the floor of the tank  2  on. Formed tank stabilizer arms  18  are welded to the rectangular side tubes  12  and braced to the interior square tubes  15  via a flanged brace plate  22 . The flanged brace plates  22  are made as two separate plates and terminated near the inside of the interior square tube members  15  to allow room for the liquid chemical tank&#39;s  2  sump trough to pass through thereby maintaining a high clearance underbody to maximize crop clearance. A hole is placed in the middle of the flanged brace plate  22  with a rolled rod  23  welded to the inside circumference for routing rubber hose through. The top flange of the formed tank stabilizer arm  18  is designed to rest against a matching recess in the liquid chemical tank. A vertical square tube  19  is secured to the outer edge of the formed tank stabilizer arm  18 . A flat square plate  20  with a hole in the center caps the top of the vertical square tube  19 . 
   Referring to  FIG. 3  and  FIG. 4A , a threaded hex nut  21  is welded to the inside of the flat square plate  20  and centered on the hole. This threaded nut  21  accepts the bolt  8  used to fasten the liquid chemical tank  2  to the carrier frame  11 . 
   Referring back to  FIG. 4  and  FIG. 4   a , the formed tank stabilizer arm  18 , the vertical square tube  19 , the flat square plate  20 , and the threaded hex nut  21  form an assembly that stabilizes the tank both longitudinal and laterally as well as establishes the rigid frame components required to hold the tank down vertically. 
   Referring once again to  FIG. 4 , a second formed intermediate cross member  25  is positioned between the formed tank stabilizer arms  18  and the lower rear cross member  14 . This second formed intermediate cross member  25  is used to tie together the longitudinal rectangular side tubes  12  and the tipped interior square tube members  15 . As with the previously described front cross member  13 , an irregular shaped plate gusset  26  must be placed at both ends of the second formed intermediate cross member  25  to help the welding adhesion to the longitudinal rectangular side tubes  12 . The liquid chemical tank&#39;s  2  trough sump is relatively shallow at the location of the second formed intermediate cross member  25  and therefore allows the member  25  to entirely span across the carriers frame without jeopardizing ground clearance. 
   Referring still to  FIG. 4  and  FIG. 5 , sliding axle plates  27  with five slotted holes are placed on the bottom side of the rectangular side tubes  12  near the rear portion of the carrier frame  11 . These sliding axle plates  27  are used to bolt a receivable axle housing assembly  28  to the carrier frame  11  in three longitudinal positions at nine inch (22.9 centimeters) increments relative to the hitch point. The ability to vary the axle&#39;s longitudinal distance provides the flexibility to achieve the desired combination of trailer tracking and balance. 
   Referring to  FIG. 4  and  FIG. 4B , a sidewall brace weldment  30  is positioned on top of the longitudinal rectangular side tubes  12  and as its name implies, provides support for the straight sidewall surface of the liquid chemical tank  2  in this area. 
   Referring again to  FIG. 4  and  FIG. 4C , rear fender support weldments  31  are placed on top of the sidewall brace weldment  30  also extending down and welded to the longitudinal rectangular side tubes  12 . The rear fender support weldment  31  extends out over the wheel assembly  7  cavity to support the portion of the tank that is positioned over the wheel assembly  7 . 
   The function and design of the middle fender support weldment  32  shown in  FIG. 4  and in detail in  FIG. 4D  is very similar to the rear fender support weldment  31  and only differs in a shorter length upper rectangular tube  34 . 
   Similarly, the forward fender support weldment  33  shown in  FIG. 4 . and in detail in  FIG. 4E  is also comparable in design and function to the rear fender support weldment  31 . Specifically, referring to  FIG. 4E , the top rectangular tube  35  and the vertical rectangular tube  36  are shorter than the matching components shown in the rear fender support weldment  31  of  FIG. 4C  and the middle fender support weldment  32  of  FIG. 4D . Referring back to  FIG. 4  and  FIG. 4E  the forward fender support  33  also has an additional vertical rectangular tube  37  that interfaces with the slanted rectangular tube of the sidewall brace weldment  30 . 
   Referring now to  FIG. 4F , the outside vertical link plates  38 , the inside vertical link plates  39 , and the interior spacer plate  40  provide the support for the rear portion of the sidewall brace weldment  30  as well as location holes for attaching the parallel linkage that supports the chemical application boom  4 . The outside vertical link plates  38  and the inside vertical link plates  39  are separated sufficiently by the interior spacer plate  40  so as to allow clearance for the parallel link assembly to be pinned between them. A short D.O.M. bushing  41  is welded in the center of the top and bottom hole locations of the outside vertical link plates  38  and a long D.O.M. bushing  42  is welded in the center of the top and bottom hole locations of the inside vertical link plates  39 . The short D.O.M. bushings  41  and the long D.O.M. bushings  42  provide an appropriate bearing surface for the pin securing the parallel linkage assembly. 
   Referring still to  FIG. 4F , a cylinder lug  43  is centered between the outside vertical side plate  38  and the inside vertical side plate  39  in a manner as to secure the base end of the hydraulic actuator that raises and lowers the application boom  4  through the parallel linkage. The hole positions of the outside vertical side plates  38 , the inside vertical side plates  39 , and the cylinder lug  43  are arranged in a geometry that produces the desired vertical travel for the application boom  4 . A formed upper cross member  44  located near the upper portion of the outer vertical side plates  38 , the inside vertical side plates  39 , and the interior spacer plate  40 , boxes these components together laterally and strengthens the carrier frame  11  against the lateral forces of the application boom  4  and the liquid chemical tank  2  at this point. 
   Preferably the liquid chemical tank  2  and corresponding carrier frame  11  provides a trailer sprayer assembly that is not inhibited from obtaining a 62½ inch (1.59 meters) on-center lateral dimension between the single wheel assemblies  7 . This 62½ inch (1.59 meters) distance allows the trailer sprayer assembly  1  to follow the towing vehicle&#39;s footprint in row crop applications where the common lateral on-center plant spacing is 30 inches (0.76 meters) and the wheel assemblies of the towing vehicle and trailer sprayer straddle three rows.  FIG. 4F  shows, the carrier frame  11  components located near the wheel assembly cavity including, but not necessarily limited to, the longitudinal rectangular side tubes  12 , the sliding axle plates  27 , the sidewall brace weldments  30 , the rear fender support weldments  31 , the middle fender support weldments  32 , the front fender support weldments  33 , the outside vertical side plates  38 , and the short D.O.M bushings  41  are configured so as not to interfere with the wheel assemblies desired 62½ inch lateral on-center dimension. 
   Referring again to  FIG. 4 , a formed platform weldment  46  is located near the front of the carrier frame  11  above the hitch weldment  45 . The purpose of the formed platform weldment  46  is to partially constrain the rinse tank  5  with the integrated platform and provide a base for the left ladder mount  47  and right ladder mount  48 . 
   A transport rack weldment  49 , shown in  FIG. 4  and in further detail in  FIG. 4G , located behind the formed platform weldment  46  and protruding up from the carrier frame  11  provides the framework necessary for supporting the chemical application booms  4  when in the folded transport position. Referring to  FIG. 4G , the height of the transport rack&#39;s upper wing rest tube  50  is such that when the application boom assembly is in the fully raised position the wings of the boom can rest on the wing rest tube  50  and not interfere with the tire assembly  7  if positioned in a lateral spacing wider than 62½ inches (1.59 meters). The left wing rest stop  51  and the right wing rest stop  52  are positioned near the top of the transport rack weldment and provide a lateral stop member for the application boom  4  to hit against when folding into the transport position. The left wing rest stop  51  and the right wing rest stop  52  are located at distance apart so that the front of folded application boom  4  angles in towards the tank for better transport visibility as illustrated in  FIG. 2B . 
   Referring now to  FIG. 6 , the approximately 1800 gallon plastic liquid chemical tank  2  as viewed from the top plan view has a symmetric wedge shape side wall profile  60  that is narrower in front and tapers to a wider dimension towards the rear of the tank. A rounded semispheric front head profile  61  and rounded semispheric back head profile  62  contributes to the structural integrity of the tank ends which is necessary due to the hydrostatic pressure and dynamic surging forces of the liquid. The tank&#39;s top fill port  63  is laterally centered on the crown  82  of the tank and longitudinally positioned near the forward edge. The forward location of the top fill port  63  allows it to be easily accessed from the operator&#39;s platform for top loading chemicals or additives. Projecting from the top fill port  63  and extending to the back head profile  62  is a raised roof ridgeline  81 . This raised roof ridgeline  81  is elevated slightly above the crown  82  of the tank and enhances the structural integrity of the crown  82 . Also shown in  FIG. 6  are the upper baffle indentations  64  located behind the top fill port  63 . The upper baffle indentations  64  create a protrusion on the inside of the tank&#39;s crown  82  for locating and securing the top of the internal baffle assembly described herein. 
     FIG. 7  shows lower baffle indentations  65  are positioned in the lower radiused portion of the liquid chemical tank  2  and create an internal protrusion similar to the upper baffle indentations  64  for locating and securing the lower section of the internal baffle assembly. 
   Referring to  FIG. 7  and  FIG. 8 , the baffle assembly consists of two inboard panels  69  and two outboard panels  70  separated by two struts  71 . The purpose of the baffle assembly in the liquid chemical tank  2  is to diminish the dynamic longitudinal liquid surging that is generally present when the tank is less than completely full. The baffle assembly is designed so that the inboard panels  69  and outboard panels  70  slide into place engaging the lower baffle indentations  65  and the upper baffle indentation  64  from the center of the liquid chemical tank  2 . Once in position they are secured from sliding back to the center of the tank by bolting the strut members  71  between the two inboard panels  69 . 
   Also shown in  FIG. 7  and in further detail in  FIG. 8 , the dropped bottom  66  of the tank fits snugly between the two longitudinal rectangular side tubes  12  and the sloped bottom  67  adjacent to the sump trough  68  is well supported by the tipped longitudinal square tubing members  15 . 
   Now referring to  FIG. 4  and  FIG. 7 , the forward flat base  72  of the liquid chemical tank  2  provides a flat surface to carry the front of the tank on the intermediate cross member  16  and formed channel members  17  on the carrier frame  11 . As its name implies, the rear flat base  73  is located at the back of the liquid chemical tank  2  and similar to the forward flat base  72  provides a flat surface to support the back of the tank on the lower rear cross member  14  of the carrier frame assembly  11 . 
   Referring still to  FIG. 4  and  FIG. 7 , two large tank stabilizer indentations  77  are symmetrically placed in the front half of tank  2 . The outside upper surface of these indentations is designed to rest on the top flange of the formed tank stabilizer arm  18 . This stabilizer configuration supports the lower portion of the tank in this area and also provides the framework to stabilize the tank both laterally and vertically. 
   Referring now to  FIG. 3  and  FIG. 7 , located directly above the stabilizer indentations  77  are the tank hold down pockets  78 . These pockets provide a recessed flat surface into the side of the tank for the UHMW hold down tab  10  to secure the liquid chemical tank  2  to the carrier frame  11 . 
   Referring to  FIG. 7  the sump trough  68  is laterally centered in the floor of the tank and runs longitudinally along most of the tank between the forward flat base  72  and the rear flat base  73 . The bottom of the sump trough has two inclined surfaces; a forward incline  74  and a rear incline  75  that slope towards the front of the tank to flow the tank&#39;s liquid into the sump well  76 , the lowest portion of the tank, where the liquid is pulled from. The rear incline&#39;s  75  shallower sloping angle is required to avoid interference with the receivable axle housing  28 , shown in  FIG. 5 , when located in the furthest forward position. Referring again to  FIG. 7 , the sump well  76  is the lowest portion of the tank and all surfaces, protrusions, and indentations of the tank are designed to allow liquid from anywhere in the tank to drain to this lower protrusion. A flat surface on the bottom of the sump well  76  allows drain fittings to be installed in this area. The sump well  76  is longitudinally located slightly back from the top fill port  63  so that if high density product is added through the top fill port  63  it does not immediately sink into the sump well  76  and get pulled from the tank. 
   Referring to  FIG. 1 ,  FIG. 7 , and  FIG. 9 , a front sparger tube recess  79  is located near the bottom front of the tank and a rear sparger tube recess  80  is located near the bottom rear of tank  2 . These two surfaces provide a flat area in the front head profile  61  and the rear head profile  62  near the lower portion of the tank  2  so threaded fittings can be installed to secure a full length agitation or sparger tube longitudinally through the length of the tank  2 . In the embodiment presented, the sprayer assembly liquid is intended to be supplied to the front of the sparger tube and the back of the tube capped. For this reason the front sparger tube recess  79  is significantly deeper than the rear sparger tube recess  80  so various pipe fittings can be secured to the sparger tube and not interfere with the rinse tank  5  located in close proximity to the front of the liquid chemical tank  2 . 
   Referring now to  FIG. 5  and  FIG. 7 , wheel wells  83  are recessed into the rear portion of the tank to create a cavity for the wheel assembly  7  to reside when positioned in the minimum 62½ inch (1.59 meters) on-center lateral dimension. The wheel well  83  must also accommodate the wheel assemblies  7  longitudinal position whether placed in the forward, middle or back position relative to the hitch point. A forward rib  84 , a middle rib  85  and a back rib  86  recess are incorporated to enhance the rigidity of the tank&#39;s side walls and upper portion of the deep recessed wheel well. While the ribs alone contribute to the structural integrity of the wheel well cavity, they are also designed to encompass the front fender support  33 , middle fender support  32  and rear fender support  31  weldments of the carrier frame  11 . 
   Obviously, many modifications and variations of the present invention are possible in light of the above teachings. It is therefore understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.