Abstract:
The present invention provides a fluid dispensing system and method wherein, after dispensing a fluid, a scavenging pump is used to remove (i.e., scavenge) residual fluid from the dispensing hose without encountering the drawbacks of the prior art. Another advantage is that the scavenging pump can be utilized for priming a main fluid supply used to supply fuel to the dispensing hose.

Description:
RELATED APPLICATIONS  
       [0001]     This application hereby incorporates by reference and claims the benefit of U.S. Provisional Application No. 60/554,841 filed Mar. 19, 2004. 
     
    
     FIELD OF THE INVENTION  
       [0002]     The present invention relates generally to a fluid dispensing system and method. More particularly, the invention relates to a fluid dispensing and scavenge system for dispensing fuel or other fluids and scavenging residual fluid from a dispensing hose.  
       BACKGROUND OF THE INVENTION  
       [0003]     Fluids, in particular fuels, are often dispensed using flexible dispensing hoses that typically are unwound from a reel in order to dispense fluid from a source tank to the tank to be filled, which may be a fuel tank of a vehicle, a radiator of a vehicle, etc. A valve or nozzle generally is provided on a dispensing end of the hose for controlling the flow of the fluid. To dispense fluid, a pump is activated to supply fluid to the dispensing hose for dispensing, and the valve is opened to allow the fluid to flow. When dispensing is complete, the valve is closed and the dispensing hose is retracted, such as by rewinding the hose onto the reel.  
         [0004]     After dispensing a fluid, residual fluid often remains in the dispensing hose. If the dispensing hose is to be rewound on a reel, the residual fluid can make rewinding the dispensing hose difficult. A common practice to remove the residual fluid from a dispensing hose has been for the operator to raise the dispensing hose to allow the fluid to drain back to the source tank. Alternatively, the fluid has been drained from the dispensing hose to the environment. However, lifting the dispensing hose can be tiresome and tedious, and draining the dispensing hose into the environment wastes the fluid and/or can contaminate the environment.  
       SUMMARY OF THE INVENTION  
       [0005]     The present invention provides a fluid dispensing system and method wherein, after dispensing a fluid, a scavenging pump is used to remove (i.e., scavenge) residual fluid from the dispensing hose without encountering the drawbacks of the prior art. Another advantage is that the scavenging pump can be utilized for priming a pump used to supply fuel to the dispensing hose.  
         [0006]     In accordance with one aspect of the invention, a fluid dispensing system and method are characterized by a dispensing hose, a main fluid supply for supplying fluid from an inlet to the dispensing hose for dispensing of the fluid at a dispensing end of the hose remote from the inlet, and a scavenging pump for scavenging fluid from the dispensing hose when fluid is no longer being dispensed from the hose.  
         [0007]     In accordance with another aspect of the present invention, a fluid dispensing system comprises a main fluid supply for supplying fluid from an inlet to an outlet to which a dispensing hose can be connected, and a scavenging pump connectable to the outlet for scavenging fluid, whereby fluid can be scavenged from the dispensing hose through the outlet.  
         [0008]     Further features of the invention will become apparent from the following detailed description when considered in conjunction with the drawings. 
     
    
     DRAWINGS  
       [0009]      FIG. 1  is a schematic diagram of a fluid dispensing system according to the present invention.  
         [0010]      FIG. 2  is a schematic diagram of the fluid dispensing system of  FIG. 1 , illustrating operation thereof in a scavenge mode.  
         [0011]      FIG. 3  is a schematic diagram of the fluid dispensing system of  FIG. 1 , illustrating operation thereof in a priming mode.  
         [0012]      FIG. 4  is a schematic diagram of another embodiment of a fluid dispensing system according to the present invention.  
     
    
     DETAILED DESCRIPTION  
       [0013]     Referring now to the drawings in detail, and initially to  FIG. 1 , an exemplary fluid dispensing system  10  according to the invention will be described. The fluid dispensing system  10  generally comprises a tank  12 , a pumping assembly  14  having an outlet  44 , and a dispensing hose  16  connected to the outlet  44 . The dispensing hose  16  is generally a collapsible hose and includes a nozzle  18  on a dispensing end thereof. The nozzle  18  includes a nozzle valve  20  which, when open as in  FIG. 1 , allows dispensing fluid for example into a tank, such as the fuel tank of a vehicle. A reel  22  is provided for storing and maintaining the collapsed dispensing hose  16  in an orderly fashion. A suitable fitting  24  connects the dispensing hose  16  to the pumping assembly  14 . A discharge filter  25  can be provided to filter contaminants from the fluid prior to dispensing.  
         [0014]     The pumping assembly  14  generally comprises a main pump  26  having a pump inlet  28  connected by piping  30  to an inlet  32  in communication with the interior of the tank  12 . In general, any suitable type of pump can be used for the main pump  26 . The inlet  32  typically is located near the bottom of the tank  12  and an inlet screen  34  can be provided between the inlet  32  and the pump inlet  28  for filtering contaminants from the fluid prior to the fluid entering the main fluid supply  26 . A pump outlet  36  is connected via piping  38  to a pumping assembly outlet  44  to which the dispensing hose  16  is attached. A check valve  40  for preventing back-flow through the main pump  26  and a valve  42  are located between the pump outlet  36  and pumping assembly outlet  44 .  
         [0015]     In general, fluid is dispensed from the fluid dispensing system  10  by unwinding the dispensing hose  16  from the reel  22 , inserting the nozzle  18  into the tank or other receptacle to be filled, activating the main pump  26  to supply fluid to the dispensing hose  16 , and opening the nozzle valve  20  to allow the fluid to flow into the tank to be filled. In  FIG. 1 , arrows A indicate the fluid flow direction through the fluid dispensing system  10  during dispensing. When dispensing is complete, the nozzle valve  20  is closed, the main pump  26  is deactivated, and the dispensing hose is collapsed and rewound onto the reel  22 .  
         [0016]     It will be appreciated that residual fluid remains in the dispensing hose  16  after dispensing a fluid and must be removed to collapse the dispensing hose  16 . As previously noted, an operator may lift the dispensing hose  16  to allow the fluid to drain back into the tank  12 . Alternatively, the residual fluid may be discharged to the environment. However, lifting the dispensing hose  16  can be tiresome and tedious for an operator, and discharging the fluid to the environment wastes the fluid and/or can contaminate the environment.  
         [0017]     In accordance with the present invention the pumping assembly  14  further comprises a scavenging pump  46  which in the illustrated embodiment is located inside the tank  12 . The scavenging pump  46  has a scavenging pump inlet  48  connected to the pumping assembly outlet  44  via piping  50  and a scavenging pump outlet  52  connected via piping  54  to the interior of the tank  12 . The scavenging pump  46  preferably is a positive displacement pump, but any suitable type of pump can be used. After dispensing a fluid, the scavenging pump  46  scavenges the residual fuel from the dispensing hose  16 .  
         [0018]     Turning to  FIG. 2 , in general scavenging the dispensing hose  16  is performed with the nozzle valve  20  and valve  42  closed. By closing the valve  42 , fluid is prevented from flowing through the main pump  26 . Thus, the scavenging pump  46  draws the residual fluid from the dispensing hose  16 , as illustrated by arrow A. Preferably, the scavenged fluid is returned to the tank  12 . Removal of the residual fluid from the dispensing hose  16  causes the dispensing hose  16  to collapse. Once the residual fluid is removed, the dispensing hose  16  can be rewound on the reel  22 .  
         [0019]     In some applications it is desirable to scavenge residual fluid from rigid or semi-rigid (i.e., non-collapsible) pipes  56  or dispensing hoses  16 . It will be appreciated that in order to scavenge a non-collapsible pipe  56  or dispensing hose  16  with the scavenging pump  46 , negative pressure in the system must be relieved to allow the residual fuel to be removed. One manner of relieving the negative pressure is to bleed air into the non-collapsible pipe  56  or dispensing hose  16 . Therefore, a bleed valve  58  can be provided to allow air to enter the pipe  56  or dispensing hose  16 . For example, in  FIGS. 1-3 , a bleed valve  58  is included on the nozzle  18  and allows air to enter the dispensing hose  16  during scavenging to relieve the negative pressure. Alternatively, the nozzle valve  20  can function as a bleed valve when opened by the operator during the scavenging process to allow air to enter the dispensing hose  16 .  
         [0020]     In general, when air is bled into the fluid dispensing system  10  to facilitate scavenging a non-collapsible pipe  56  or hose  16 , the scavenging pump  46  is deactivated once the air reaches the scavenging pump  46  so as to limit the amount of air that is pumped into the tank  12 . Typically, the operator may listen for the air to reach the scavenging pump  46  and manually shut off the scavenging pump  46  when the presence of air is detected. The scavenging pump  46  can also be switched off via a pressure switch  60  that detects the presence of air in or near the scavenging pump  46 .  
         [0021]     Turning to  FIG. 3 , it will be appreciated that the scavenging pump  46  can also be utilized to prime the main pump  26  prior to dispensing fluid from the dispensing hose  16 .  FIG. 3  is identical to  FIG. 1  except that the nozzle valve  20  is closed. As shown by arrows A, when the scavenging pump  46  is activated with the nozzle valve  20  closed and the valve  42  open, fluid is drawn through the main pump  26  by the scavenging pump  46  and returned to the tank  12 . In this manner, the scavenging pump  46  can prime the main pump  26 .  
         [0022]     It will now be appreciated that the main pump  26  and scavenging pump  46  can be configured to operate simultaneously. Thus, prior to dispensing, with the nozzle valve  20  closed and the valve  42  open, the main pump  26  and scavenging pump  46  can be activated together. In this configuration, the main pump  26  will be primed by the scavenging pump  46 . To begin dispensing the fluid, the nozzle valve  20  is opened to allow fluid to flow therethrough. As mentioned, the valve  42  remains open during dispensing. The scavenging pump  46  can continue drawing fluid from the pumping assembly outlet  44  during dispensing. When dispensing is complete, the nozzle valve  20  and the valve  42  are closed, thereby causing the scavenging pump  46  to scavenge the residual fluid from the dispensing hose  16 . Therefore, it will be appreciated that in the illustrated embodiment the closing and opening of the valve  42  effectively controls whether the scavenging pump  46  scavenges fluid from the dispensing hose  16  or primes the main pump  26 . However, as desired the main pump  26  and the scavenging pump  46  can be operated independently.  
         [0023]     In the embodiment of  FIGS. 1-3 , some of the components of the pumping assembly  14 , including the main pump  26  and scavenging pump  46 , are located within the tank  12 . However, in other applications it can be desirable to have some or all of the components of the pumping assembly  14  located external to the tank  12 .  
         [0024]     Turning to  FIG. 4 , a schematic of another embodiment in accordance with the present invention having the scavenging pump external to the tank will be described. The fluid dispensing system  110  generally comprises a tank  112 , a fluid supply  114  having an outlet to which a dispensing hose can be connected, and two dispensing hoses  116 . The dispensing hoses  116  are generally collapsible hoses and include nozzles  118  and nozzle valves  120  which, when open, allow dispensing fluid. A reel (not shown) can be provided for storing and maintaining the collapsed dispensing hoses  116  in an orderly fashion. Valves  122  can be provided to separately control flow to the dispensing hoses  116 . A suitable union or fitting  124  connects the dispensing hoses  116  to the fluid supply  114 .  
         [0025]     The fluid supply  114  generally can include pump  126  located within the tank  112  and having a pump inlet  128  in communication with the interior of the tank  112 . Alternatively, the fluid supply  114  can be a gravity feed for supplying fluid. As in the previous embodiment, any suitable type of pump can be used for the pump  126 . A pump outlet  136  is connected via piping  138 , and manual valves  140   a,    140   b,    140   c  to a fluid supply outlet  144 . One or more of the valves  140   a,    140   b,    140   c  can be motor-driven valves. A plurality of unions  145  can also be provided as necessary to connect portions of the pipe  138 . The fluid supply outlet  144  is connected to the fitting  124  to which the dispensing hoses  116  are connected.  
         [0026]     The fluid supply  114  further comprises a scavenging pump  146  located outside the tank  112  and having a scavenging pump inlet  148  connected via piping  150  and union  152  to the fluid supply outlet  144  and/or the dispensing hoses  116 . A valve  154  is provided on the fitting  124  side of the union  152  to control the flow of fluid from the fitting  124 . A scavenging pump outlet  156  is connected via piping  158  and union  160  to the interior of the tank  112 . A valve  162  is provided to control the flow of fluid from the tank  112 . The unions  152  and  158  and valves  154  and  162  can be in the form or a quick-connect self-sealing valve thereby making installation and removal of the scavenging pump  146  from the fluid dispensing system  110  easier.  
         [0027]     The operation of the fluid dispensing system  110  of the present embodiment is similar to the operation of the previously described embodiment. It will be appreciated that the scavenging pump  146  can also prime the pump  126  in a manner similar to the priming process described previously.  
         [0028]     After dispensing is complete, the dispensing hoses  116  can be scavenged by the scavenging pump  146 . To scavenge the dispensing hoses  116 , the valve  140   c  is closed to prevent fuel from flowing through the outlet  144 . Any residual fuel in the dispensing hoses  116  is scavenged by the scavenging pump  146  and returned to the tank  112 . In general, collapsible dispensing hoses  116  are used and collapse upon removal of the residual fuel. However, in the case of a non-collapsible dispensing hose  116 , a bleed valve (not shown) can be opened, or the nozzle valves  120  opened, to allow removal of the residual fuel in the manner described in connection with the previous embodiment.  
         [0029]     The pipe  138  can also be scavenged by the scavenging pump  146  in the manner previously described in connection with scavenging non-collapsible pipes and hoses. In the present embodiment, a bleed valve  164  is provided on the pipe  138  to allow air to enter the pipe  138  at a location downstream from the valve  140   b.  To scavenge the pipe  138 , valves  140   a  and/or  140   b  are closed and valve  140   c  remains open while the scavenging pump  146  is operated. Air is bled into the pipe  138  via bleed valve  164  thereby allowing the removal of the residual fuel. The bleed valve  164  can be a manual valve or an automatic valve that opens to permit air to enter the pipe  138  when a predetermined pressure is reached within the pipe  138 .  
         [0030]     It will be appreciated that the scavenging pump  146  in this embodiment can be attached and removed readily from the rest of the fluid dispensing system  110 . Thus, the scavenging pump  146  can be attached to the system  110  when scavenging and/or priming is required, and detached when no longer needed. In this regard, it will be appreciated that with appropriate fittings and piping, the scavenging pump  146  can be retrofitted to existing fluid dispensing systems.  
         [0031]     It further will be appreciated that any number of dispensing hoses  16 ,  116  can be used with the present invention. For example, the present invention can be used in conjunction with a mobile refueling vehicle wherein one or more large fuel tanks are mounted on a truck or other vehicle for dispensing fuel in remote locations. In such an application, multiple dispensing hoses  16 ,  116  can be provided. The priming and scavenging features of the present invention are particularly advantageous for mobile refueling because of the transient nature of the operation. For example, a truck may travel to a first location whereat several dispensing hoses may be used to fill multiple vehicles. These dispensing hoses are typically collapsible and stored on reels to save space and weight onboard the refueling vehicle. Thus, at each fueling location, the hoses must be unwound to dispense fuel and retracted onto the reels before the mobile refueling vehicle can depart to another fueling location. The scavenging feature of the present invention can make retracting and stowing the dispensing hoses more efficient. Further, the priming feature of the present invention can be of particular use for a mobile refueling operation because the main fluid supply may be more likely to require priming after transit, especially across rough terrain.  
         [0032]     Although the invention has been shown and described with respect to a certain preferred embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a “means”) used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.