Abstract:
The present invention therefore aims at providing a nozzle that reduces the amount of residual fuel left on a spout after fueling by encouraging the residual fuel to drip into the container to be filled. A fuel dispensing nozzle is comprised of a nozzle body, a fuel regulating valve, and a spout for directing the fuel supply from the regulating valve to and in the container to be filled. After a fueling cycle, fuel clings to both the inside and outside spout surfaces and can be considered a falling film. Wherein existing nozzle spouts have discontinuous spout end faces that impede the flow of falling films into the container to be filled, the improved nozzle and endface according to the present invention encourage the falling films to create drops that fall into a container to be filled.

Description:
CROSS REFERENCE TO RELATED APPLICATION 
   There are no related applications. 
   STATEMENT REGARDING FEDERALLY SPONSORED R&amp;D 
   Not applicable to this application. 
   TECHNICAL FIELD 
   This invention relates to a fuel nozzle and more particularly to a fuel dispensing nozzle that promotes residual fuel on the nozzle spout to drip into a container to be filled prior to the spout being removed from the container. 
   BACKGROUND OF THE INVENTION 
   Fuel dispensing nozzles are widely used and understood in the field. Fuel nozzles are used for directing and regulating a flow of fuel into a container to be filled. Typical fuel nozzles are comprised of a nozzle body, a valve assembly for regulating fuel flow, and a tubular spout. 
   Recently, significant attention has been directed to the adverse environmental effects caused by fuel dispensing nozzles. Fuel nozzles create vapors that contain volatile organics that chemically react with nitrogen oxides to form ground level ozone, often called “smog”. Ground level ozone can potentially cause irritation to the nose, throat, lungs and bring on asthma attacks. In addition, fuel vapors contain other harmful toxic chemicals, such as benzene. 
   Fuel dispensing nozzles provide several significant sources of fuel vapors, including: vapors displaced from containers as liquid is inserted; fuel dripped from nozzle spouts; and, residual fuel left on spouts after a fueling cycle. 
   The most predominant source of fuel vapors has been addressed through the implementation of vapor recovery systems, such as described by U.S. Pat. No. 5,213,142. Typical vapor recovery systems dispense fuel though a main tube of a spout and vacuum vapors through a secondary spout channel. Although vapor recovery systems can significantly reduce the amount of vapors that reach the atmosphere, the technology is expensive to install and operate, and thus has been implemented in limited areas. In addition, vapor recovery systems do not address the sources of dripping fuel or residual fuel. 
   The issues of fuel dripping and residual fuel have largely been either ignored, or inadequately addressed by equipment manufacturers. To force manufacturers to develop technology that reduces these emissions, the California Air Resource Board (CARB) has implemented a series of new requirements that must be met by nozzle manufactures. The new requirements are implemented through a series of “Phases”. One of the CARB requirements is that a fuel nozzle shall produce no more than one post fueling drop. Another requirement limits the amount of residual fuel that can be retained by a nozzle and hose assembly after fueling. 
   Many new drop reducing spouts have been created, such as: U.S. Pat. No. 5,602,364 and U.S. Pat. No. 5,645,116. Although these valve systems may reduce the amount of drops that occur, they are unlikely to consistently meet the requirements set forth by CARB. A problem with “dripless” technologies, such as listed above, is that they do not eliminate the drip creating residual fuel from the outside surfaces of the spout. In addition, the “dripless” features themselves have surfaces that can attract liquid fuel and increase the potential for drops. Many “dripless” spouts may eliminate unallowable drops in one test run, and then have one or more unallowable drops in subsequent test runs performed in the same fashion and with the same nozzle. 
   Another problem with existing nozzle technologies, such as described above, is that they do not typically work with existing “standard” (non-vapor recovery) type nozzles. These “standard” nozzles are used in a large percentage of fueling stations which are not located in highly populated areas or do not dispense large volumes of gasoline. 
   Yet another problem with existing nozzle technologies is that they require significant change-over costs. Many of the aforementioned designs require that at least a complete new nozzle be installed in order for their benefits to be realized. 
   In these respects, the improved nozzle endface surface according to the present invention substantially departs from conventional concepts of the prior art, and in doing so provide an apparatus primarily designed for the purpose of reducing the amount of vapor that reaches the atmosphere during a fueling cycle. 
   SUMMARY OF THE INVENTION 
   The present invention therefore aims at providing a nozzle that reduces the amount of residual fuel left on a spout after fueling by encouraging the residual fuel to drip into the container to be filled. A fuel dispensing nozzle is comprised of a nozzle body, a fuel regulating valve, and a spout for directing the fuel supply from the regulating valve to and in the container to be filled. After a fueling cycle, fuel clings to both the inside and outside spout surfaces and can be considered a falling film. Wherein existing nozzle spouts have discontinuous spout endfaces that impede the flow of falling films into the container to be filled, the improved nozzle and endface according to the present invention provides a nozzle spout that promotes fuel drops to form and fall into a container to be filled. 
   These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Preferred embodiments of the invention are described below with the reference to the following accompanying drawings: 
       FIG. 1  is a perspective view of a standard nozzle assembly; 
       FIG. 2  is a partial section view, along line A—A of  FIG. 1 , showing a prior art fuel dispensing spout with a square endface surface; 
       FIG. 3  is a partial section view, along line A—A of  FIG. 1 , showing a prior art fuel dispensing spout with a “ramped” outside endface surface; 
       FIG. 4   a  is partial view of the square endface surface of  FIG. 2  soon after fuel flow stoppage; 
       FIG. 4   b  is a partial view of the endface surface of  FIG. 2 , at a time after that of  FIG. 4   a , and showing a drop starting to form about its square endface; 
       FIG. 4   c  is a partial view of the endface surface of  FIG. 2 , at a time after that of  FIG. 4   b , with a drop just about to fall; 
       FIG. 4   d  is a partial view of the endface surface of  FIG. 2 , at a time after that of  FIG. 4   c , and after the last drop has fallen; 
       FIG. 5  is a partial section view, along line A—A of  FIG. 1 , showing an improved fuel dispensing spout according to the present invention; 
       FIG. 6   a  is partial view of the improved endface of  FIG. 5 , according to the present invention, soon after fuel flow stoppage; 
       FIG. 6   b  is a partial view of the improved endface of  FIG. 5 , according to the present invention, at a time after that of  FIG. 6   a , and showing a drop starting to form about its round endface; 
       FIG. 6   c  is a partial view of the improved endface of  FIG. 5 , according to the present invention, at a time after that of  FIG. 6   b , with a drop just about to fall; 
       FIG. 6   d  is a partial view of the improved endface of  FIG. 5 , according to the present invention, at a time after that of  FIG. 6   c , after the last drop has fallen; 
       FIG. 7  is a partial section view of a spout endface according to an alternative embodiment of the present invention; 
       FIG. 8  is a partial section view of an alternative embodiment spout endface; 
       FIG. 9  is a partial perspective view of a nozzle discharge end with an alternative embodiment endface surface; 
       FIG. 10  is a partial side view of the alternative embodiment of the present invention shown in  FIG. 9 ; and 
       FIG. 11  is a plot showing the improved performance of the present invention in comparison to the prior art. 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   Many of the fastening, connection, manufacturing and other means and components utilized in this invention are widely known and used in the field of the invention are described, and their exact nature or type is not necessary for a person of ordinary skill in the art or science to understand the invention; therefore they will not be discussed in detail. 
   As used herein, a reference with “′” (prime) indicates that the object is an improved object according to the present invention. 
   Applicant hereby incorporates by reference the following U.S. patents: U.S. Pat. No. 5,765,609 for an aluminum fuel spout construction; U.S. Pat. No. 5,603,364 for a “dripless” nozzle; U.S. Pat. No. 4,453,578 for a automatic shut-off nozzle; and, U.S. Pat. No. 5,213,142 for a vapor recovery system. 
   Referring now to the drawings,  FIG. 1  shows a fuel dispensing nozzle assembly  10 . Nozzle assembly  10  has an inlet end  16  for receiving a supply of liquid fuel from a hose and pump system (not shown). The flow of fuel is regulated by a valve assembly  12  and through the movement of an actuator  14 . The flow of fuel travels from valve assembly  12 , down the length of a spout  20 , out a discharge end  17 , and into a container to be filled (not shown). Spout  20  is used for directing the flow of fuel into the container to be filled. As show in  FIG. 2 , an inside spout surface  22  is in direct contact with the flow of fuel. Opposite of inside surface  22  is an exterior spout surface  23  (shown  FIG. 2 ). Connecting inside surface  22  to outside surface  23  is an endface surface  18 . 
     FIG. 1  shows a “standard” non-vapor recovery spout assembly  20 , but spout  20  may be any one of the common vapor recovery types. Spout  20  may be removably attached to a nozzle body  11  by means of a spout screw  19 . This allows spout  20  to be replaced without having to replace nozzle body  11 . 
   Spout  20  is typically made from extruded 6005-T5 aluminum. Aluminum provides a low cost, lightweight material that provides manufacturing process flexibility. U.S. Pat. No. 5,765,609 describes a process for making a low cost aluminum vapor recovery spout which has been incorporated herein by reference. Such a spout typically has a discontinuous endface surface  18  (shown in  FIG. 2 ). Square shaped nozzles are a result of the spout being cut to length from an extrusion by means of a cutoff saw. Although square and stepped square endfaces are most common, some nozzles contain a discontinuous “conical ramp” as described by U.S. Pat. No. 5,765,609 (column 7, line 8). The “conical ramp” is for minimizing any sharp edge from being a hazard, or subject to abuse in use (also shown in  FIG. 3  of this application). A sharp outside nozzle edge, as created by a cutoff saw, edge can potentially scratch car body finishes. 
   As part of the performance of nozzle assembly  10 , the role of endface surface  18  can be much more significant than just not scratching a car&#39;s paint. An improved endface  18 ′ of an improved spout  20 ′ (shown in  FIG. 5 ), according to the present invention, not only accomplishes the goals of the prior art, but it also significantly reduces the amount of fuel vapors that reach the atmosphere after a fueling cycle. Improved endface  18 ′ accomplishes this by reducing the amount of liquid drops that reach the ground. Improved endface  18 ′ also decreases the amount of residual fuel on improved spout  20 ′, fuel that otherwise would evaporate into the atmosphere. 
   Improved endface  18 ′ according to the preferred embodiment of the present invention is shown in  FIG. 5 . Improved spout  20 ′ is shown with inside surface  22  and outside surface  23 . Adjacent to discharge end  17  is improved endface surface  18 ′. Endface surface  18 ′ is generally radial and tangent to both inside surface  22  and outside surface  23 . Improved endface surface  18 ′ provides a smooth transition between inside surface  22  and outside surface  23  and the means for increasing the rate at which fuel drops fall from improved spout  20 ′. Endface  18 ′ is preferred to have a radius generally equal to half the wall thickness of improved spout  20 ′. 
   When nozzle spout  20  and improved spout  20 ′ dispenses fuel into a container to be filled, both inside surface  22  and outside surface  23  become wet with fuel. Inside surface  22  obviously wets because it directs and is in contact with the supply of fuel. Outside surface  23  becomes wet due to splashing within the container to be filled. Generally, outside surface  23  will collect less residual fuel than inside surface  22  due to a spring  24  that limits how far spout  20 , or improved spout  20 ′, can be inserted into the container to be filled. 
   After the flow of fuel through nozzle  10  is stopped (via deactivation of valve assembly  12 ), spout  20  and improved spout  20 ′ have a thin fuel film located on both inside surface  22  and outside surface  23 . This film, along with any trapped globules of fuel in close proximity to valve assembly  12 , immediately begin to flow in the direction of discharge end  17  due to the influence of gravity. 
     FIG. 4   a  through  FIG. 4   d  show how a fuel film flows under the influence of gravity with a prior art, square-shaped, endface surface  18 .  FIG. 4   a  shows a nozzle wall with inside surface  22  and outside surface  23  soon after fuel flow through nozzle  10  is stopped. An inside film  32  flows down inside surface  22  and an outside film  33  flows down outside surface  23 . Both films,  32  and  33 , travel in the direction of endface surface  18 . Because square-shaped endface surface  18  is discontinuous with inside surface  22 , and can be discontinuous with outside surface  23 , inside film  32  and outside film  33  flow to and collect at the discontinuity (both surfaces are shown discontinuous in  FIGS. 4   a  thru  4   d ). 
   At some point in time after  FIG. 4   a , as shown in  FIG. 4   b , inside film  32  and outside film  33 , have sufficient size and momentum to overcome any discontinuity between surface  18  and surfaces  22  or  23 . The fuel that formerly collected at the discontinuity now clings to endface surface  18  due to adhesion between the fuel and the aluminum spout material. The fuel adhered to surface  18  forms a potential fuel drop  34 . 
   When fuel drop  34  becomes sufficient in size to cause necking, drop  34  soon falls in the direction of gravity.  FIG. 4   c  shows drop  34  just prior to it breaking free of endface surface  18 . 
   The process of inside film  32  and/or outside film  33  creating drop  34  continues until an equilibrium is reached (shown in  FIG. 4   d ). Equilibrium can occur from multiple events. One potential mode of equilibrium occurs when films  32  and  33  are too thin to overcome the discontinuities of surface  18 . The result is a bulge of fluid between surfaces  22  and/or  23  and endface  18 . Another equilibrium event occurs when film  32  and/or film  33  evaporates faster than its propensity to flow. This is likely to occur in very warm operating conditions. Lastly, equilibrium can occur when drop  34  is insufficient in size to cause necking. 
   As previously mentioned, improved endface surface  18 ′, according to the present invention (shown in  FIG. 5 ), is generally tangent to inside surface  22  and outside surface  23 .  FIGS. 6   a  through  6   d  show how the present invention increases the rate at which drips form (increases the chances the drips will remain in the tank) and reduces the amount of fuel remaining on the nozzle at equilibrium. 
     FIG. 6   a  shows a wall of improved spout  20 ′ just after the flow of fuel through nozzle  10  is stopped. Again, inside surface  22  has an inside film  32  and outside surface  23  has a outside film  33 . Because improved endface surface  18 ′ is generally continuous to both surfaces  22  and  23 , films  32  and  33  can immediately flow to improved endface surface  18 ′ and start to form drop  34 . 
     FIG. 6   b  shows how the momentum of films  32  and  33  add to the movement of drop  34  in the direction of gravity.  FIG. 6   c  shows how drop  34  necks down in close proximity to improved surface  18 ′ thus allowing drop  34  to fall in the direction of gravity.  FIG. 6   d  shows an equilibrium condition for improved spout  20 ′. The randomness of equilibrium is reduced by the improved spout  20 ′ over that of prior art spout  20 . Randomness is reduced because the falling fuel film is unable to collect at a discontinuity; one does not exist. 
   Overall, improved endface surface  18 ′ significantly increases the rate at which dripping occurs. This acceleration of dripping significantly increases the number of drops that occur within the time that a user would shut off the flow of fuel through a nozzle and the time at which the user removes the nozzle from the container to be filled. The result is more residual fuel dripping into the container to be filled, rather than evaporating into the atmosphere or dripping onto the ground. The method of promoting dripping is a dramatic shift from the prior art practices of trying to resist dripping. 
   The test results of  FIG. 12  show the significant improvements of improved endface surface  18 ′ of the present invention over endface surface  18  of the prior art. Many more drops fell with the present invention prior to the end of a 5 second time period. This measured improvement is well before the allocated 10 second wait period provided by CARB test procedures. Because more drops fall sooner, less fuel ends up on the ground or left on the nozzle spout. 
   Although the present invention does not provide “dripless” performance, the improvements of the technology can be added to existing designs for improved performance and at a low cost. The present invention can be applied to standard nozzles, vapor recovery nozzles and “dripless” nozzles. Wherein millions of automobile tanks are fueled every day, the present invention creates an opportunity for significant environmental savings. 
   Other embodiments of the present invention are possible.  FIG. 7  shows an elliptically curved improved endface surface  18 ′.  FIG. 8  shows an offset endface surface  18 ′ wherein the curve of surface  18 ′ is biased in one direction or the other and still remains generally tangent to both surfaces of the spout.  FIGS. 9 and 10  show yet another alternative embodiment of the present invention wherein the creation of drops is encouraged by improved endface surface  18 ′ having one or more protrusions in the axial direction of spout  20 . The axial protrusions provide the means of increasing the rate at which fuel drops fall from spout  20  by focusing the falling films into drip locations. The axial protrusions can be radial, as shown, triangular, or elliptical and the such. 
   Operating the improved spout  20 ′ according to the present invention is unchanged from the prior art. The user inserts improved spout  20 ′ into the container to be filled and actuates the flow of fuel through nozzle body  11 . When the fluid reaches the desired level, the flow of fuel stops and the user removes improved spout  20 ′ from the container to be filled. The result, is a transparent method of reducing the amount of harmful vapors emitted into the atmosphere during the fueling cycle. 
   Improved endface surface  18 ′ can be manufactured into new nozzles via a number of widely known metal manufacturing processes. In addition, improved endface  18 ′ may also be re-manufactured into existing nozzles by either refurbishing the nozzles or by reworking on site. Another method of practicing the present invention is to insert a secondary tip into an existing spout. Yet another method is to manufactur the present invention into an inside fill tube, as sometimes used with vapor recover systems. 
   While the low liquid retention fuel nozzle systems herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise form of assemblies, and that changes may be made therein without departing from the scope and spirit of the invention as defined in the appended claims.