Patent Publication Number: US-6659143-B1

Title: Vapor recovery apparatus and method for gasoline dispensing systems

Description:
BACKGROUND 
     This invention relates to a vapor recovery apparatus and method and, more particularly to such an apparatus and method for recovering gasoline vapors from a gasoline dispensing systems. 
     In a gasoline service station for dispensing gasoline to vehicles, several gasoline dispensing units, or pumps, are provided which receive gasoline stored in one or more underground storage tanks and dispense the gasoline, via dispensing nozzles, to the vehicles. 
     In these arrangements, gasoline vapor is present in the fuel tank of the vehicle and released from the gasoline flow which can discharge to atmosphere if not properly recovered. In compliance with government regulations that require this gasoline vapor to be recovered, various types of systems have evolved. 
     By far the most common recovery systems of this type utilize a dual hose arrangement with one hose supplying the gasoline from the underground storage tank to the dispensing nozzle for dispensing into the vehicle, and the other hose passing the gasoline vapors from the vehicle tank to the underground storage tank. With all currently known vapor recovery systems of this type, extensive vapor return piping, along with associated pumps and valves, are required to conduct the collected vapor from the vehicle tank, through the dispensing unit and back to the underground storage tank. Of course, in relatively old installations, if this piping has not been provided during the initial construction, the station forecourt has to be dug up to install the underground portion of the system, which considerably adds to the cost of the installations. 
     Therefore what is needed is a vapor recovery system that eliminates the need to transfer the recovered vapors to the underground gasoline storage tank, and therefore eliminates the cost and complexity of such systems. 
     SUMMARY 
     The present invention is directed to an apparatus and method for recovering vapor during the dispensing of fuel via a hose into a vehicle tank. An embodiment of the invention has a compressor disposed in a vapor passage. The compressor is activated in response to the dispensing of the fuel for drawing the vapor from the tank and into the vapor passage. Blades on the compressor separate the air from the gasoline vapor. The recovered vapor is reintroduced into the fuel flow and the air is released to the atmosphere. 
     An advantage of the invention is that it operates by motion of the fluid flow to the vehicle tank, and therefore saves on electrical power cost because no electrical power is needed. 
     An advantage of the invention is that recovered vapor can be reintroduced back into the fuel stream at the fuel hose, thereby eliminating a lengthy fluid path back to the source fuel tank. This reduces the susceptibility of the system to leaks, for example in the dispenser itself, in the underground pipes, or at the fuel tank or tank vent. Also, because the recovered vapor is not routed to the fuel tank, it does not pressurize the fuel tank. 
    
    
     These and other advantages of the invention will be come apparent from the following Drawings and Description of the Preferred Embodiment. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an isometric view of a gasoline dispensing unit employing vapor recovery apparatus according to an embodiment of the present invention. 
     FIG. 2 is an enlarged, cross-sectional view of the vapor recovery apparatus of the embodiment of FIG.  1 . 
     FIG. 3 is an enlarged portion of the component of FIG.  2 . 
    
    
     DESCRIPTION OF A PREFERRED EMBODIMENT 
     With reference to FIGS. 1 and 2 of the drawings, the reference numeral  10  refers, in general, to a gasoline dispensing unit consisting, in general, of a dispenser housing  12 , and a hose tower  14  extending to one side of the housing. 
     The housing  12  includes a front bezel, or panel,  16 , a side portion of which overlaps a portion of the hose tower  14 . The center portion of the panel  16  is slightly recessed and includes a display  18  for displaying information relating to the gasoline dispensing operation. A credit card reader  20  and a receipt dispenser  22  are provided to the side of the display  18 , and a series of octane select buttons  24  are mounted below the display  18 . 
     A door  26  extends over a compartment in the lower portion of the housing  12  below the panel  16  which receives hydraulics including a conduit  28  that extends to an underground storage tank for the gasoline to be dispensed. Although not shown in the drawings, it is understood that the conduit  28  also extends to the hose tower  14  for passing gasoline to one end of a hose assembly  30  which extends from a fitting  32  at the upper portion of is the tower. A nozzle  34  is connected to the other end of the hose assembly  32  for dispensing the gasoline to a vehicle. 
     A hose assembly  30   a  extends from a fitting  32   a  extending from the upper portion of the tower  14 , and receives a nozzle  34   a  The hose assembly  30   a  and the nozzle  34   a  are similar to the hose assembly  30  and the nozzle  34 . Although not shown in the drawing, it is understood that the dispenser housing  12  has a rear panel that receives similar components as the panel  16  which are associated with the hose assembly  30   a  and which function in a similar manner to the latter components. 
     A pump (not shown) is provided for pumping the gasoline from the storage tank to the conduit  28  when the unit  10  is activated, so that the gasoline flows through the conduit  28  and the hose assembly  30  to the nozzle  34  which can be manually activated for dispensing the fuel into the gasoline tank of a vehicle. The nozzle  34  also has an inlet for receiving a mixture of gasoline vapor and air from the latter tank during the dispensing of the gasoline, which mixture is processed in a manner to be described. 
     As shown in FIG. 2, the hose assembly  32  includes an inner hose  36  and an outer hose  38  extending over, or around, a portion of the inner hose. The inner hose  36  receives gasoline from the conduit  28  (FIG. 1) and passes it to the nozzle  34  in a direction shown by the solid-line arrow in FIG. 2. A portion of the inner hose  36  has a reduced-diameter portion to form a venturi section  37  for forming a reduced pressure zone for reasons to be described. 
     A separator unit  40  extends over a portion of the inner hose  36  near the fitting  32 , and includes an casing  42  which is greater than the outer diameter of the inner hose  32   a  to form an annular chamber  44 . The casing  42  is preferably circular in cross section and includes a first truncated, frusto-conical portion  42   a  that is tapered inwardly in a direction away from the hose tower  14  (FIG.  1 ); and a second truncated frusto-conical portion  42   b  that extends from the portion  42   a , and is tapered outwardly in the same direction. 
     The upper end of the casing portion  42   a  is open, and an annular coupling plate  46  is attached to the lower end of the casing portion  42   b . The inner hose  36  extends through the casing  42 , and the corresponding end of the outer hose  38  is coupled to the plate  46  and extends over the inner hose  36  from the plate to the nozzle  34 . The inner diameter of the outer hose  38  is greater than the outer diameter of the inner hose  36  to form an annular, vapor recovery, passage  50  which receives gasoline vapor from the vehicle tank, via the nozzle, during the dispensing of the gasoline. 
     A turbine  54  is mounted for rotation in the inner hose  36 , and has a plurality of blades  54   a  extending from a central shaft. The blades  54   a  are in the path of the gasoline flowing through the inner hose  36  so that the fluid causes rotation of the turbine. 
     A compressor  60  is rotatably mounted in the chamber  44  and extends around the downstream end portion of the turbine  54 . The compressor  60  includes a plurality of concave, porous, and hydrodynamically smooth blades  60   a  extending from a hollow shaft  60   b  that surrounds the inner hose  36 . The blades  60   a  are arranged in an opposite direction to the blades  56  of the turbine  54  and are hollow to form a passage for receiving vapor that passes through the porous walls of the blades as will be described. The compressor  60  is magnetically coupled to the turbine  54  so that the above rotation of the turbine  54  causes corresponding rotation of the compressor  60 . 
     A rotor  62  is also rotatably mounted in the chamber  44  and extends around the upstream end portion of the turbine  54  in a spaced relation to the compressor  60 . The rotor  62  includes a plurality of concave, porous, and hydrodynamically smooth blades  62   a  extending from a hollow shaft  62   b  that surrounds the inner hose  36 . The blades  62   a  are also arranged in an opposite direction to the blades  54   a  of the turbine  54  and are also hollow to form a passage for receiving vapor that passes through the porous walls of the blades as will be described. The rotor  62  is free-spinning, and a stator  64  is mounted to the exterior surface of the casing  42  in radial alignment with the rotor  62 . The stator  64  interacts aerodynamically with the rotor in a manner to be described. 
     The turbine  54  is mounted in the inner hose  26 , and the compressor  60  and the rotor  62  are mounted in the chamber  44 , in a manner to enable them to rotate about their respective longitudinal axes while being restrained against axial movement. This mounting of the turbine  54 , the compressor  60  and the rotor  62 ; as well as the magnetic coupling between the turbine and the compressor and rotor are done in a conventional manner such as disclosed in U.S. Pat. No. 5,217,051 the disclosure of which is incorporated by reference. 
     Two axially-spaced, annular ring seals  66   a  and  66   b  are provided at the radial outer edges of the compressor blades  60   a  and the rotor blades  62   a , respectively, and are attached to the blades in any know manner. An annular collector  68  has a portion extending along the inner wall of the casing portion  42   b  in alignment with the ring seals  66   a  and  66   b.    
     As better shown in FIGS. 3 and 4 in connection with one of the blades  60   a  of the compressor  60 , a nipple  70  is formed on the outer edge of each blade  60   a  and extends though a slot formed in the seal ring  66   a  and to a port  68   a  formed in the collector  68 . The end of the nipple  70  is porous so that vapor collected in the interior of each blade  60   a  passes through the corresponding nipple, and into the collector  68 . Although not shown in FIG. 3, it is understood that nipples, similar to the nipple  70 , are provided on the remaining blades  60   a  of the compressor  60  and on all of the blades  62   a  of the rotor; and that corresponding slots are provided in the seal rings  66   a  and  66   b , and corresponding ports are provided in the collector  68 . 
     The remaining portion of the collector  68  extends axially upstream from the portion of the collector discussed above, and then radial inwardly to the venturi section  37  of the inner hose  36 . The aforementioned rotatable seal formed by the ring seals  66   a  and  66   b  and the collector  68  confines the axial movement of vapor through the collector. 
     In operation, gasoline is pumped from the storage tank, through the conduit  28  (FIG. 1) to the hose tower  14 , and through the inner hose  36  to the vehicle to be serviced, in the direction indicated by the solid arrow in FIG.  2 . The turbine  54  thus rotates in proportion to the flow of gasoline through the hose  36  by virtue of the forces applied by the gasoline to the blades  54   a . Due to the magnetic coupling between the turbine  54  and the compressor  60 , the compressor rotates in the chamber  44  in a direction opposite the direction of rotation of the turbine. 
     The rotation of the compressor  60  creates forces that draw a mixture of air and gasoline vapors from the vehicle tank through the nozzle  34 , into and through the passage  50 , and into the chamber  44  as indicated by the dotted-dashed arrows in FIG.  2 . 
     The air/vapor mixture in the chamber  44  is compressed by the compressor  60  and a portion of the relative light air of the mixture is separated from a portion of the relatively heavy vapor due to the vapor layering, by molecular weight, on the smooth, porous surfaces of the compressor blades  60   a . The separated vapor, which consists largely of hydrocarbons, passes through the pores of the blades  60   a  into the interior of the blades, and through the nipples  70  of each blade, before passing through the ports  68   a  of the collector  68  and into the interior of the collector, with this movement being assisted by the centrifugal force of the motion of the blades  60   a.    
     The remaining portion of the mixture and the separated air from the above first-stage separation passes to the rotor  62 , with the force of the mixture and the air on the blades  62   a  of the rotor causing it to rotate in a direction opposite the direction of rotation of the compressor. A second-stage separation of the relative light air from the relatively heavy vapor of a portion of the mixture occurs by the vapor components of the mixture layering, by molecular weight, on the smooth, porous surfaces of the rotor blades  62   a . The separated vapor, which consists largely of hydrocarbons, passes through the pores of the blades  62   a , into the interior of the blades, and through the nipples of each blade, before passing through the ports of the collector  68  and into the interior of the collector, with this movement being assisted by the centrifugal force of the motion of the blades  62   a . During this separation, the stator  64  interacts aerodynamically with the rotor  62  in a manner to reduce turbulence and promote laminar flow of the air/vapor mixture along the surface of the blades  62   a  to promote the separation. 
     The low pressure caused by the venturi section  37  of the inner hose  36  provides a suction train that promotes permeation of vapor through the porous blades  60   a  and  62   a , through the ports  68   a  of the collector  68 , and through the collector, as described above. The venturi section  37  of the inner hose  36  is also porous so that the vapor passes from the collector  68  into the interior of the hose. In the hose  36  the collected vapor mixes with the gasoline flowing through the hose and is thus reintroduced into the vehicle. The separated air is discharged through the open end of the casing portion  42   a  as shown by the dotted arrows. 
     Therefore, the above embodiment eliminates the need for costly and complex vapor recovery systems that require transferring the recovered vapor from the vehicle tank to the gasoline storage tank. 
     It is understood that variations may be made in the foregoing without departing from the scope of the invention. For example, it is understood that one or more additional rotor/stator sets can be used as needed to accomplish substantially complete separation of the gasoline vapors from the air. Also, the terms “hose”, “conduit”, “passage” etc. are not limited to any particular fluid flow device but are equally applicable to all such devices. Also, spatial references, such as “upper”, “lower”, etc. are for the purpose of illustration only and do not limit the specific orientation or location of the structure described above 
     Since other modifications, changes, and substitutions are intended in the foregoing disclosure, it is appropriate that the appended claims be construed broadly and in a manner consistent with the scope of the invention.