Abstract:
This drop tube loading arm assembly is adaptable for loading asphalt into tank trailers at marketing terminals. The telescoping drop tube employs guides made of steel rollers of polymers such as fluorocarbon polymers and aluminum. The guides are located in the annular space between the tubes in combination with increased radial clearance between the tubes or sleeves and in combination with protection for the overfill probe. With the addition of vapor control systems and overfill protection probes, the telescoping drop loading spouts are less susceptible to cold weather sticking problems.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation-in-part of U.S. patent application Ser. No. 10/894,373 filed Jul. 19, 2004 now U.S. Pat. No. 6,932,123. 
    
    
     TECHNICAL FIELD OF THE INVENTION 
     This invention relates to a drop tube loading arm assembly, for loading volatile liquid storage tanks such as fuel tanks and asphalt tanks. 
     BACKGROUND OF THE INVENTION 
     The present relates to volatile liquid storage tanks and more particularly to such tanks having apparatus for reducing vapor generation when the tank is filing from the upper or top side of the tank. These tanks could include asphalt terminals, tank trucks, above ground petroleum fuel tanks, chemical storage tanks, mobile liquid storage containers, and the like. The focus of this invention will be on filling tank trucks from asphalt terminals. The invention, however, has application with other tank types as well. 
     Tanks can be mounted on tanker trucks or located underground at service stations. Tanker trucks are typically filled with the fluids using pumping equipment at the loading racks of marketing terminals, and underground storage tanks are typically gravity-filled from the trucks. An overfill protection device is used with each tank to disable the pumping equipment at the marketing terminals or to close a truck-mounted flow valve at the service station when the limit of the recipient tank&#39;s capacity is reached. 
     Detection probes are placed near sources such as gasoline or asphalt storage tanks. The probes are connected by wires to a central monitoring station which monitors the probe status. These detection probes include overfill probes. 
     Asphalt loading arms have a history of cold weather sticking problems. Two and three stage telescoping drop tube loading arms have been used in the past to meet this problem. Both trailers and spouts could be positioned in marketing terminals to save lane time. The telescoping drop spouts were less susceptible to cold sticking problems due to the geometry being a direct drop. 
     With the addition of vapor control systems and overfill protection probes, the telescoping drop loading spout configuration became more complex. The vapor control telescoping loading spouts frequently had smaller annular clearances between tubes. In colder weather, sticking problems occurred due to the smaller annular clearances. Other problems surfaced as well. 
     BRIEF DESCRIPTION OF THE INVENTION 
     As a result, we developed a novel drop tube loading arm assembly. The assembly especially is adaptable for loading asphalt into tank trailers at marketing terminals. The telescoping drop tube employs placed guides made of aluminum or polymers such as fluorocarbon polymers and strategically placed aluminum guides. The guides are located in the annular space between concentric tubes. This in combination with increased radial clearance between the tubes or sleeves and in combination with protection for the overfill probe, has greatly improved the cold weather sticking problem. 
     The telescopic drop tube assembly of this invention for use with a tank while filling the tank from a liquid source comprises a first hollow drop tube having a length, a hollow interior, an exterior, an upper end adaptable for coupling to the liquid source and a lower end; and a second hollow drop tube having a length, a hollow interior, an exterior, an upper end, a lower end and a spout connected to the lower end adaptable for coupling to a tank. A portion of the upper end of the second drop tube circumscribes and forms a sleeve around an exterior portion of the lower end of the first drop tube. The second drop tube then is slidably mounted around the exterior of the first drop tube. A fluid overfill detector probe is connected to the spout; as is a vapor recovery nozzle. For a three stage loading tube the polymer guides are connected to the interior of the second and third sleeve, and aluminum guides are connected to the exterior on all three sleeves. 
     A two stage loading tube is similar to a three stage loading tube except the upper middle tube with guide assembly is omitted. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a side view of the telescopic drop tube assembly of this invention showing the tubes in a retracted position. 
         FIG. 2  is a side view of the telescopic drop tube assembly of  FIG. 1  showing the tubes in a extended position. 
         FIG. 3  is an enlarged, fragmentary sectional view showing the spout, fluid detector overfill probe and vapor recovery nozzle in greater detail. 
         FIG. 4  is an end view showing the annular spacing of the spout and telescopic end tubes. 
         FIG. 5  is an enlarged, fragmentary sectional showing the polymer guides, annular space and annular glide rails in greater detail. 
         FIG. 6  is an end view showing rotating guides in the voids between end tubes. 
         FIG. 7  is a downward perspective view showing rotating guides engaging a tube of the assembly. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In a preferred embodiment, a glide rail is connected to the exterior of the first drop tube, and the second drop includes an annular slot, wherein the annular slot is slidably mounted against the glide rail. The assembly also includes circuitry and a monitor wherein the circuitry connects the fluid overfill detection probe to the monitor. A controller and its circuitry connects the controller between the monitor and the liquid source. A vapor recovery hose and a vapor recovery manifold as included wherein the vapor recovery hose connects the vapor recovery nozzle to the vapor recovery manifold. In another preferred embodiment, a protective plate connected to the spout to protect the fluid overfill detector probe. 
     The polyfluorocarbon polymer guide varies widely. Preferably, the guide is a polyfluorocarbon polymer. This term includes polytetrafluoroethylene (PTFE), polymers of chlorotrifluoroethylene, fluorinated ethylene-propylene and the like. The term also includes copolymers of these polymers. Preferably, the polyfluorocarbon is tetrafluoroethylene hexafluoropropylene vinylidene fluoride (THV) copolymers. 
     Preferably, the guide is made from DuPont&#39;s Teflon™ polymer, which is a tetrafluoroethylene (TFE) fluorocarbon polymer. 
     In addition to the preceding combination of elements, the drop tube assembly of this invention preferably includes the following features: add to plate to protect probe, position bucket hook, add lock down handle, use Sch. 40 SST instead of aluminum, make collar threaded SST for easy access to guides, make plate removable for easy access to guides, with radial clearance of ¼″ for both sleeves, fully weld guides on pipe OD, make handles from 1″ aluminum, provide easy way to identify locking lug position, add bolt &amp; nut to be field welded to existing cross bar (design upper bracket for lower or higher profile), and add 1″ aluminum pipe handle to locate the locking lug. 
       FIG. 1  is a side view of the telescopic drop tube assembly of this invention showing the tubes in a retracted position.  FIG. 1  shows drop tube assembly  10 , which includes first hollow tube  12  and second hollow tube  14 . Coupling  16  connects tube  12  a liquid source (not shown). Fitting  18  attaches to the upper end of tube  14 . Fitting  18  and tube  14  circumscribe tube  12  and are slidably mounted around the exterior of tube  12 . Preferably, fitting  18  is collar threaded SST for easy access to the guides. Handles  20  typically are one inch aluminum rods for moving tube  14  upwardly or downwardly along tube  12 . Movement may be manually or automated with electronic or mechanical means. 
     Spout  22  is connected to the lower end of tube  14  and is adaptable for coupling to a tank. Fluid overfill detector probe  24  is connected to spout  22 . Probe  24  includes sensor pipe  26 . Probe  24  through sensor pipe  26  detects a fluid state of their respective environments. Probe electronics connects probe  24  to a monitor via conventional electrical cable. The monitor may provide a signal for detecting a fluid environment or it may automatically shut off the flow of fluid. 
     Spout  22  also comprises a pair of hollow tubes with a void therebetween. Spout  22  comprises exterior tube  28 , interior tube  30  and void  32  therebetween. Vapor recovery nozzle  34  connects to exterior tube  28  and communicates with void  32 . Vapor recovery nozzle connects to a vapor recovery manifold via a vapor recovery hose. 
     Vapor recovery manifold and vapor recovery hose may be a conventional system or they may be a vapor recovery system as described in copending patent application Ser. No. 10/894,173, filed Jul. 19, 2004, entitled Loading Rack Odor Control, the disclosure of which is herein incorporated by reference. 
       FIG. 1  also shows probe protector plate  36 . 
       FIG. 2  is a side view of the telescopic drop tube assembly of  FIG. 1  showing the tubes in an extended position. Tube  14  is lowered to the lower end of  12 . In this fashion tube  14  telescopically drops around tube  12  with fitting  18  remaining engaged to the outer surface of tube  12 . 
       FIG. 3  is an enlarged, fragmentary sectional view showing spout  22 , fluid detector overfill probe  24  and vapor recovery nozzle  34  in greater detail. 
       FIG. 3  shows platform  48  circumscribing spout  22  and housing probe  24 . Spout  22  also includes handles  40  for ease of movement. Also shown is eyelet bolt  42  secured to spout  22 . One end of hook  44  couples to eyelit bolt  42  and the other end of hook  44  is attached to cable  46 . Cable  46  attached to a standard or custom winch or hoist. The wrench or hoist may be electronic, hydraulic or pneumatic. Electric worn drives and wire rope hoists may be used as well. These means are used for lifting, lowering, and positioning spout  22 . 
       FIG. 3  also shows platform  48  circumscribing spout  22  and housing probe  24 . 
       FIG. 4  is an end view showing the annular spacing of the spout and telescopic end tubes.  FIG. 4  shows tube  14 , exterior tube  28  and interior tube  30  in greater detail. Void  32  between tube  28  and tube  30  also is shown. Sensor pipe  26  and protector plate  36  also are shown.  FIG. 4  shows a plurality of guides  52  connected to the exterior of tube  30  and engaging the interior of tube  28 .  FIG. 4  also shows a plurality of guides  58  connected to the exterior of tube  14  and engaging the interior of tube  30 . While a plurality of guides is shown, any number of guides may be employed in the voids between tubes. The guides may slidably or rotatably engage the surfaces of the tubes. As will be shown in  FIG. 6 , the guides may be arranged in a mirror image of those shown in  FIG. 4 . 
       FIG. 5  is an enlarged, fragmentary sectional showing the polymer guides, annular space and annular glide rails in greater detail.  FIG. 5  shows polymer guide  50  bolted to flange  52 . Guides  50  may be a metal such as aluminum or a plastic such as a flurocarbon polymers. Flange  52  is welded to the interior of spout  22 . Glide rail  54  is welded to the exterior of tube  14  and spout  22  includes annular slot  56  which is slidably mounted against glide rail  54 . 
       FIG. 6  is another end view showing the annular spacing and guides between tubes.  FIG. 6  shows a plurality of guides  60  connected to the interior of tube  28  and rotatably engaging the exterior of tube  30 .  FIG. 6  also shows a plurality of guides  62  connected to the interior of tube  30  and rotatably engaging the exterior of tube  14 . Rotating portion  60 ′ and  62 ′ of guides  60  and  62  respectively, may be a wheel, roller, roller bearing, ball or ball bearing. Preferably rotating portion  60 ′ and  62 ′ is a wheel or roller. 
       FIG. 7  is a downward perspective view showing rotating guides engaging a tube of the assembly.  FIG. 7  shows a plurality of guides  70  connected to the interior of fitting  18  and engaging the exterior of tube  12 . Rotating portion  72  of guides  70  may be a wheel, roller, roller bearing, ball or ball bearing. Preferably rotating portion  72  is a wheel or roller. 
     In addition to these embodiments, persons skilled in the art can see that numerous modifications and changes may be made to the above invention without departing from the intended spirit and scope thereof.