Patent Publication Number: US-7712259-B1

Title: Sump cover system for underground liquid storage tanks

Description:
RELATED APPLICATION 
   FIELD OF THE INVENTION 
   The present invention relates to underground liquid fuel storage tanks and, more particularly, to new and improved covering system for underground fuel storage tanks. 
   BACKGROUND OF INVENTION 
   Underground fuel storage tanks are required by law to prevent liquid leaks below ground to avoid soil and groundwater contamination. To meet this requirement, tanks conventionally include a water tight sump shield assembly that collects any fuel leakage from pipes, valves, or other equipment at the upper part of the tank. Sensors and alarms are also provided as an alert to such condition. Water that enters the sump, for alarmed base sumps, is occasionally falsely sensed as a fuel leak, requiring immediate examination and corrective action. 
   It is known in the art that the covers for sump assemblies cannot remain properly sealed against rain and other water runoff. Such runoff seeks the lowest level and can enter the sump assembly. This water when mixed with the aforementioned fuel leakage also creates a contaminated condition that must be dealt with promptly. This condition wastes much time and effort, and, therefore, expense to deal with recurring contamination. More seriously, as described below, the cover sealing problem becomes worse over time to the point when the sump can fill completely with water run-off and fuel mixture. This can lead to an overflow of fuel-contaminated water that can contaminate surrounding soil often leading to fines, contamination clean-up, and the expense of digging up the concrete-imbedded leaking assembly and replacing it with a new sump assembly and concrete. 
   The principal cause of the above problems stems from the standard sump covers, which do not provide a seal strong or reliable enough to prevent water from entering the containment sump. Weak cover seals can result from poor design, poor installation, poor materials, and the like. 
   Many sumps are made of polyethylene or other plastics. Cover leakage also results from installed or migrating back fill or concrete, which initially or over time, compresses the sump into an egg-shape or other distortion. The plastic under constant pressure tends to flow and distort causing the distorted sump opening lip to breech the circular, metal cover seal. 
   Sump assembly manufacturers have tried to overcome these problems, such as providing a unit that seals on the inside surface of the sump by means of an expandable plug design. Unfortunately, each unit needs to be customized to fit a particular design criterion, such as size of the collar opening, etc. If the unit distorts in the field, then the operator must wait until a new plug is manufactured to the new dimensions, which may result in fines, shut-down, or contamination. Thus, customizing for each unit increases the costs of the product and requires complex and delayed supply practices. 
   Another commercial unit relies on epoxies or other adhesives to seal the cover to the collar lip. Bonding materials compatible with polyethylene have only recently been introduced to the market. But these materials are not compatible with fuel hydrocarbons and may themselves contaminate the fuel being pumped or stored. 
   Accordingly, there is a need for a fuel storage containment sump shield assembly that provides a watertight seal over a long period of time to prevent water from entering the containment sump assembly for underground fuel storage tanks. 
   SUMMARY OF EXEMPLARY EMBODIMENT OF INVENTION 
   The present invention solves the above mentioned problems and provides a sump cover system that is quickly installed, excellently sealed against liquid intrusion, designed to fit a wide variety of sump dimensions, and, if necessary, is easily disassembled and re-assembled. 
   One exemplary embodiment of the invention includes a support ring with a wide sealing member, EG gasket, which seats on the sump upper lip; one or two compression brackets are placed below the riser of the sump. Elongated members, that can have adjustable lengths, extend from the compression brackets and attach to spaced zones of the support ring. Each elongated member includes a shortening or tension device, such as a turn buckle. As the elongated member is shortened, the top of the compression bracket engages the riser. Further tightening or turning the turn buckle compresses the support ring on to the sealing member, and, in turn, the sealing member on to the sump collar lip to achieve a liquid-tight seal. 
   A cover is secured to the support ring by suitable devices, such as fasteners or the like. In one example, the top of the support ring includes a number of upstanding threaded studs. The cover, preferably dome-shaped, has an outer lip region that includes a series of openings that marry to the number of threaded studs. The cover is installed by placing the cover in to the support ring with the studs extending through the openings. Wing or other nuts can be threaded to the studs to secure the cover on to the support ring. Preferably, the cover can also include a port for inspection or some access to the sump interior without disassembling the system. The port can be closed with a removable but sealing port cover and port gasket. 

   
     DESCRIPTION OF THE DRAWINGS 
     Other and further objects, advantages, and benefits of the present invention shall become apparent with the following detailed description of an exemplary embodiment according top the principals of the present invention, when taken with the appended drawings, in which: 
       FIG. 1  is a side elevation, vertical section of a typical below ground sump including an installed exemplary embodiment of the cover system  10  according to the principles of the present invention. The vertical section is along line  1 - 1  of  FIG. 3 . The vertical and circular arrows show the tightening rotation of wing nuts  18  on to studs  16 . 
       FIG. 2  is the same view of “Detail A” in  FIG. 1 . 
       FIG. 3  is a horizontal section taken along line  3 - 3  of  FIG. 1 . 
       FIG. 4  is a perspective, exploded view of the support ring, sump cover, and port cover of  FIG. 1 . 
       FIG. 5  is similar to  FIG. 1  (without cover  20 ) showing the bracket and support ring assembly for a sump having a medium height collar. 
       FIG. 6  is similar to  FIG. 5  for a sump having a minimum height collar. 
   

   DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS OF THE INVENTION 
   With reference to  FIGS. 1-4 , a system  10  according to the principles of the present invention is shown installed on a sump  59  having a collar  62  and a riser  64 . System  10  includes support ring  12  having a series of spaced, upstanding, threaded studs  16  on its top surface and a depending lip  17  at its outer periphery. Gasket  14  locates between ring  12  and the top ridge or lip of collar  62 . Ring  12  also includes attachment holes (not shown) or devices, such as D hooks  19 , for connection to the upper parts of the elongated members, such as turn buckles  32  and chains  33 . Cover  20  is preferably dome-shaped with a horizontal outer lip region that installs on to ring  12 . Cover  20  includes a series of openings that receive the series of studs  16 . Wing nuts  18  secure to cover to ring  12 . 
   One or more compression brackets  26  are spaced laterally from the sump diameter preferably on opposite sides of the same diameter. Brackets  26  engage riser  64  from below and are secured by elongated members  35  extending from brackets  26  to the support ring  12 . Elongated members  35  serve to apply upward force on brackets  26  compressing their upper end into engagement with rise  64  underside. Tension members  35 , in this example, include turn buckles  32  having their upper end connected to D hooks  19  and a length of chain  33 , cord, or rod extending from turn buckle  32  lower end to an eye-hook  28  threaded, welded, or bolted or otherwise connected to compression bracket  26 . If desired, “S” hooks  30  may be used to connect chain  33  to bracket  26 , generally as shown. Ring  12  and gasket  14  form an excellent seal with the top of the collar  62  because the gasket is compressed between the ring  12  and top lip of collar  62  due to the tension applied to the tension member  35  by turn buckle  32 . 
   Cover  20  can also include inner walls  22  that define an inspection or access port preferably at the top of the cover  20 . Walls  22  can be threaded or otherwise designed to receive a port cover  24  to seal the port until access to the port is desired. 
   Sump Cover System Installation 
   The system installation shall now be described starting with a top exposed, below ground sump. One embodiment of the present invention fits sumps from 27″ to 34″ in diameter, however additional sizes can be accommodated without departing from the present invention. The installation takes a few minutes, requires no adhesive or epoxy, and usually requires only an adjustable wrench tool, a measuring tape or ruler, and potentially a metal saw or cutting tool. Steps 4A, B, &amp; C below are in the alternative. 
   Installation steps can generally include:
         Step 1. Determine if the system cover will fit by measuring the diameter of the collar lip. One exemplary embodiment of the invention will fit sump diameters of 27″ to 34″.   Step 2. Place the support ring  12  on top of the sump  62  lip with studs  16  facing upward. In the unlikely event the top lip of collar  62  is not flat and has a recess of greater than one-quarter inch, a hand or air operated plane can be used to level the lip surface.   Step 3. Before or after step 2 above, measure the height of the sump collar from about the top of the riser  64  to the top of the sump collar. This height shall determine which suspension configuration, more fully described below, will optimize the system reliability and integrity.   Step 4A. If the height of collar  62  is greater than 10 inches, see  FIG. 1 . Extend the turn buckles fully by screwing or rotating them outward. Connect the bottom of turn buckle  32  to the top of the length of chain  33 . Hold the chain assembly and place it inside the sump and connect the top of turn buckle  32  to the D-hook  19 . Lower the chain into the sump. Lower bracket  26  into the sump and pull up to engage the bracket ends with riser  64 . Slip an S-hook  30  through a chain  33  link and the other end of the S-hook  30  through hook  28  of bracket  26 . Repeat for the other tension member  35  to suspend bracket  26  from the two associated tension members  35 . Then retract turn buckles  32  to apply upward force on bracket  26  until its ends engage riser  64  with suitable compression force causing ring  12  to compress gasket  14  against sump collar  62  lip thus forming a reliable liquid seal at the collar  62  top. This completes installation of that respective bracket assembly. It is recommended that excess chain lengths be cut and removed from the sump to avoid interference with housed equipment or maintenance thereof.   Step 4B. If the height of the collar is 5″-10″, see  FIG. 5 . Use of the chains is unnecessary, and the turn buckles  32  are connected directly between bracket hooks  28  and D-hooks  19 . S-hooks  30  may or may not be used as desired. Installation is similar to that described above, except elongated members  35  need not include chains, cords, or the like. Brackets  26  are forced against riser  64  by retracting turn buckles  32  to complete the bracket assembly installation and gasket seal at the sump collar top lip.   Step 4C. If the height of the collar is less than 5″, see  FIG. 6 . Use of the chains is unnecessary. Turn buckles  32  are connected directly between bracket hooks  28  and D-hooks  19 . Either a smaller sized turn buckle can be used or, alternatively, spacer blocks  27  can be placed on the outer ends of brackets  26 , which blocks  27  become compressed between riser  64  and bracket  26  when turn buckles  32  are screwed for retraction causing ring  12  to compress gasket  14  against collar  62  top lip forming a reliable liquid seal therewith.   Step 5. Regardless of the configuration of the suspension/compression configuration, the system installation is completed by installing the sump cover  20  with wing nuts  18  screwed down on studs  16 , and threading port cover  24  on to the access port  22 .       

   It will be understood that various modifications and enhancements and changes may be made to the various herein disclosed exemplary embodiments without departing from the spirit and scope of the present invention. The collar and other dimensions stated above are exemplary and should not be taken as limiting the application of the present invention. The drawings are not necessarily drawn to scale but are designed to more clearly illustrate the functionality and features of the principles of the present invention. Although the above exemplary embodiments include corrugated plastic sumps, the invention is also applicable for metal sumps and non-corrugated sumps.