Abstract:
A double-walled flexible dispenser sump connection system prevents fuel leaks into a dispenser sump located below a fuel dispenser. An inner flexible connector and an outer flexible connector are configured such that the dispenser sump connection system may be installed on newly constructed fuel delivery systems or be retrofitted onto existing fuel delivery systems in order to bring them into compliance with recently environmental regulations.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation patent application of U.S. patent application Ser. No. 12/143,349 filed Jun. 20, 2008, issuing under U.S. Pat. No. 7,527,065 on May 5, 2009, which is continuation patent application of U.S. patent application Ser. No. 11/679,618 filed Feb. 27, 2007 now abandoned, which is a continuation patent application of U.S. patent application Ser. No. 11/061,388 filed Feb. 18, 2005 now abandoned, the entire contents of which are incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates generally to fuel dispenser sumps used in gas stations and in similar applications, and more particularly to a double-walled flexible dispenser sump connection system that provides a safeguard against leaks from dispenser sumps located beneath the gasoline dispensers. 
     BACKGROUND AND SUMMARY OF THE INVENTION 
     State environmental and energy agencies require strict compliance with laws and regulations regarding fuel storage and conveyance, in particular regarding containment of fuel within the pipes and other components beneath the ground surface at gas stations. Piping systems for conveying the fuel between the underground tanks and dispensers must be pressurized and vacuum sealed to detect and contain leaks therein. 
     Referring to  FIG. 1 , there is shown a common dispenser sump connection system  10  below a fuel dispenser  12  at a gas station. Fuel is conveyed from a tank  14  through a primary inner pipe  16 , traditionally two inches in diameter, into a dispenser sump  18  below the fuel dispenser  12 . Once inside the dispenser sump  18  the inner pipe  16  continues through an elbow joint  20  to a connecting inner pipe  22 , which couples to a shear valve  24  located at the bottom of the fuel dispenser  12 . The shear valve  24  prevents fuel spills or leaks in the event that the fuel dispenser  12  is displaced from the dispenser sump  18 . 
     A secondary outer pipe  26 , traditionally three inches in diameter, encloses the inner pipe  16  from the tank  14  to the dispenser sump  18 . The outer pipe  26  prevents fuel from entering into and contaminating the groundsoil and/or the atmosphere. The interstitial space between the outer pipe  26  and the inner pipe  16  is either pressurized or vacuum sealed to provide additional protection against leaks. 
     Although the outer pipe  26  contains any leaks between the tank  14  and the dispenser sump  18 , the outer pipe  26  terminates into a boot at the dispenser sump  18 , leaving the inner pipe  16  is exposed inside the dispenser sump  18 . Therefore, there are no safeguards to detect or contain leaks that occur inside the dispenser sump  18 , which can result in leaks into the groundsoil surrounding the dispenser sump  18  and/or into the atmosphere. Recently, regulations have been passed in several states such as California which require safeguards be installed to prevent leaks from dispenser sumps. Currently the approved safeguards require retrofitting the existing dispenser sump with the equivalent of an outer sump around the dispenser sump within the space between the outer and inner sump being either pressurized or vacuum sealed, or replacing the existing dispenser sump with a double-walled pressurized sump. The cost to install the outer sump or replace the existing sump costs approximately $2,000 minimum per dispenser. Considering that most gas stations have multiple dispensers, the cost to retrofit the existing sumps to bring them into compliance can be substantial. 
     The present invention comprises a dispenser sump connection system which overcomes the foregoing and other difficulties which have long since characterized the prior art. In accordance with the broader aspects of the invention, an outer and inner flexible connector system provides protection against fuel leakage from the dispenser sump. The inner flexible connector connects the primary inner pipe to the shear valve. The outer flexible connector completely encloses the inner flexible connector from the sump wall to the shear valve. The interstitial space between the outer flexible connector and the inner flexible connector is pressurized and/or be vacuum sealed thereby preventing any fuel leakage into the dispenser sump. 
     The outer and inner flexible connector system can be retrofitted inside existing dispenser sumps at a minimal cost per dispenser. The present invention provides the high level of protection against leakage required by state environmental agencies and eliminates the need for installing an outer sump or retrofitting with a double-walled sump. 
    
    
     
       DESCRIPTION OF THE DRAWINGS 
       A more complete understanding of the invention may be had by reference to the following Detailed Description when taken in conjunction with the accompanying Drawings, wherein: 
         FIG. 1  is a sectional view illustrating a prior art fuel delivery and dispenser sump connection system; 
         FIG. 2  is a sectional view of the double-walled flexible dispenser sump connection system of the present invention; 
         FIG. 3  is an exploded perspective view of the dispenser sump connection system shown in  FIG. 2 ; and 
         FIG. 4  is a sectional view of the dispenser sump connection system shown in  FIG. 2 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the Drawings, and particularly to  FIGS. 2 ,  3 , and  4  thereof, there is shown the dispenser sump connection system  30  of the present invention. An inner flexible connector  32  is connected to the inner pipe  16  for completing the conveyance of fuel to the fuel dispenser  12 . An outer flexible connector  34  is installed over and completely encloses the inner flexible connector  32 . The lower end of the outer flexible connector  34  is connected in fluid communication with the outer pipe  26 . The upper end of the outer flexible connector  34  is connected to the shear valve  24  thereby completing the containment of any leaks from either the inner pipe  16  or the inner flexible connector  32 . The interstitial space between the outer flexible connector  34  and the inner flexible connector  32  is either pressurized or vacuum sealed thereby preventing any fuel leakage into the dispenser sump  18 . The flexible connectors  32  and  34  used in conjunction with the present invention are described in detail in U.S. Pat. Nos. 7,140,648; 6,922,893; and 7,063,358. 
     In the embodiment shown in  FIGS. 2 through 4 , the inner flexible connector  32  couples to the inner pipe  16  through an elbow joint  36  comprising an inner elbow joint  38  secured to the distal end of the inner pipe  16  and an outer containment clamshell  40 , which glues over the inner elbow joint  38  to contain any leaks that may occur therefrom. The dispenser sump connection system  30  of the present invention may also be secured directly to the inner and outer pipes  16  and  26 , or by other connection means known to those skilled in the art and suitable for use in fuel and hazardous material delivery systems. 
       FIG. 3  is an exploded view and  FIG. 4  is a sectional view of the dispenser sump connection system  30 . The inner flexible connector  32  threadedly secures into the inner elbow joint  38 , thereby completing the connection of the inner flexible connector  32  to the inner pipe  16 . The top of the inner flexible connector  32  has male threads for threadedly securing the inner flexible connector  32  into the shear valve  24 . The outer flexible connector  34  installs over the inner flexible connector  32  and is connected to the elbow joint  36  by a lower connection ring  42 , which extends around the end of the inner elbow joint  38 . The outer containment clamshell  40  when glued over the inner elbow joint  38  covers and thereby contains the connection of the lower connection ring  42  to the inner elbow joint  38 . 
     The lower end of the outer flexible connector  34  is secured to the lower connection ring  42  by a first hinged circular clamp  44  having a threaded locking mechanism  46 . A gasket  48  is mounted between the outer flexible connector  34  and lower connection ring  42 . Wedge shaped surfaces on the outer flexible connector  34  and on the lower connection ring  42  and corresponding shapes on the inner surfaces of the hinged circular clamp  44 , combined with the gasket  48 , cause the outer flexible connector  34  and the lower connection ring  42  to form a compression seal as the threaded locking mechanism  46  is tightened. 
     The upper end of the outer flexible connector  34  is connected to the shear valve  24  by an upper connection ring  50 . The outer flexible connector  34  is secured to the upper connection ring  50  by a second hinged circular clamp  44  having a threaded locking mechanism  46 . A gasket  48  is positioned between the outer flexible connector  34  and upper connection ring  50 . Wedge shaped surfaces on the outer flexible connector  34  and on the upper connection ring  50  and corresponding shapes on the inner surfaces of the hinged circular clamp  44 , combined with the gasket  48 , cause the outer flexible connector  34  and the upper connection ring  50  to form a compression seal as the threaded locking mechanism  46  is tightened. The upper connection ring  50  comprises female threads for threadedly securing an outer housing  52  of the shear valve  24  thereinto. 
     Near the upper end of the outer flexible connector  34  is an orifice  54  which facilitates either vacuum sealing or pressurization of the interstitial space between the inner flexible connector  32  and the outer flexible connector  34 . The lower connection ring  42 , the upper connection ring  50 , and the hinged circular clamps  44  may be formed from stainless steel, bronze, brass, monel, other metals, various polymeric materials, and other materials that will not be adversely affected by the fluid that will flow through the inner and outer flexible connectors  32  and  34 . The inner elbow joint  38  and the outer containment clamshell  40  are commercially available parts used in conjunction with fuel delivery systems and other hazardous material delivery systems. 
     Although preferred embodiments of the invention have been illustrated in the accompanying Drawings and described in the foregoing Detailed Description, it will be understood that the invention is not limited to the embodiments disclosed, but is capable of numerous rearrangements, modifications, and substitutions of parts and elements without departing from the spirit of the invention.