Abstract:
A method of repairing a leaking spill container by lining the existing unit. Additionally the liner can be used to convert a single walled spill container into a double walled spill container.

Description:
FIELD OF THE INVENTION 
       [0001]    The present invention relates to containment of fluids and, more particularly, to the containment of fluids in overfill or spill containers. 
       BACKGROUND OF THE INVENTION 
       [0002]    Prior to 1988 the US EPA determined that significant pollution was occurring in the US due to fuel leaking from a number of sources at fueling facilities (gas stations). Tanks, piping from tanks to dispensers, fuel leaks at the dispensers and fuel discharges caused by overfilling tanks and from fuel remaining in the filling hoses all contributed to pollution at fueling facilities. The US EPA established guidelines for upgrading fueling facilities including requiring a means of catching fuel discharged in the process of filling the tanks. These catchment basins came to be know as “Spill Containers”, “Spill Containment Manholes”, “Spill Containment Buckets” and a host of other similar descriptions. Some spill containers were and are manufactured out of welded metal. Other less expensive spill containers were and are manufactured using a plastic bellows. The plastic bellows style of spill container became the popular choice and is found at most fueling facilities today. 
         [0003]    Over time spill containers themselves have started leaking. Some States have now regulated the testing and certifying of the spill containers on a periodic basis. As an example, the State of Alabama has started requiring that spill containment manholes be hydrostatically tested. Any leaking spill container must be repaired or replaced or the service station can be shut down until the offending spill container can be replaced. Since the installation of the first spill containment manholes in the late 1980&#39;s there has been a need for an inexpensive repair of leaking spill containers. 
         [0004]    Presently the only known solution is to replace the manhole with a new one. 
         [0005]    Replacing an existing spill containment manhole is an expensive process requiring in most instances that at least part of the site be closed while repairs are being performed. Excavating equipment is required, concrete must be broken and removed and a new spill container must be purchased and installed. Delays may be encountered to obtain permits. My recent survey, conducted in 2008, of replaced spill containers indicates the cost is approximately $4500 per unit. This cost does not account for lost fuel revenues, costs of permits and any clean up costs associated with the uncovering of contaminated soils surrounding the leaking spill container. 
         [0006]    It would be advantageous to provide a liner that is fuel resistant. 
         [0007]    It would also be advantageous to provide a liner that can be made to closely match the inside of the existing spill container so as to minimize the loss of capacity of the spill container once the liner is in place. 
         [0008]    It would also be advantageous to provide a liner that can create a total seal between the snow plow ring installed on the surface of the fueling facility and the riser pipe extending from the fuel tank. 
         [0009]    It would also be advantageous if the cost of the liner installed is a fraction of replacing the spill container. 
         [0010]    It would also be advantageous if the spill container can be repaired without breaking concrete or using construction equipment. 
         [0011]    It would also be advantageous if the liner could be installed within a few hours by a single technician. 
         [0012]    It would also be advantageous if the liner could be coated with a film of material that is highly chemically resistant to the liquids to be encountered. 
         [0013]    It would further be advantageous if the liner could be used to convert an existing single walled spill container to a double walled spill container. 
       SUMMARY OF THE INVENTION 
       [0014]    In accordance with the present invention, there is provided a method of repairing a leaking spill containment manhole by lining the existing unit. Additionally the liner can be used to convert a structurally sound single walled spill containment manhole into a double walled spill containment manhole. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0015]    A complete understanding of the present invention may be obtained by reference to the accompanying drawings, when considered in conjunction with the subsequent, detailed description, in which: 
           [0016]      FIG. 1  is a cross section view of an existing spill container with a plastic bellows; 
           [0017]      FIG. 2  is a cross section view of an existing spill container with a metal body; 
           [0018]      FIG. 3  is a cross section view of the components required to manufacture a liner; 
           [0019]      FIG. 4  is a cross section view of a bellows style spill container with a drain valve mounted on a tank riser; 
           [0020]      FIG. 5  is a cross section view of a bellows style spill container where fill has been added to cover the irregular shape of the bottom of the spill container; 
           [0021]      FIG. 6  is a cross section view of an of the liner showing the coated surface, ready to be installed in a bellows style spill container; and 
           [0022]      FIG. 7  is a cross section view of a bellows style spill container with the liner installed. 
       
    
    
       [0023]    For purposes of clarity and brevity, like elements and components will bear the same designations and numbering throughout the Figures. 
       DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0024]    This invention is best understood by referring initially to existing spill containment manholes in  FIG. 1  and  FIG. 2 .  FIG. 1  is a cross section view of a spill containment manhole with a bellows  20  style body, a snow plow ring  22  (common to most spill containers), a base  24  (common to most spill containers), a drain valve  26  (common to most spill containers) and a tank riser  28  (common to all spill containers).  FIG. 2  is a cross section view of a spill containment manhole with a metal body in lieu of the bellows  20 -style body shown if  FIG. 1 . The spill containment manhole in  FIGS. 1 and 2  are connected to a 4″ tank riser  28  extending from the top of the buried fuel tank. The surface of a fueling facility is covered with a concrete slab. The snow plow ring  22  is mounted more or less flush with the top of the concrete slab. Attached to the snow plow ring  22  is the rest of the spill container. The bellows  20  is normally attached to the underside of the snow plow ring  22  by means of bolts through a lip on the top of the bellows  20  terminating into the bottom of the snow plow ring  22 . The bellows  20  is terminated to the base  24  in any number of manners including bolts, band clamps or other securing devices. The riser inside the spill container is terminated into the base  24  of the spill container. Often a drain valve  26  is installed in the base  24  so that liquids captured in the spill container may be drained into the tank riser  28 . All seams or joints created at the junction of the various components may create leak paths. Spill containers that incorporate a plastic bellows  20  have proven to have a high failure rate of the bellows  20  itself. There are at least nine different spill containment manufacturers and each may have multiple configurations of their spill containers. It is not necessary to identify all the permutations that may be encountered in the field.  FIGS. 1 and 2  represent cross sections of typical spill containers encountered in the industry. Irrespective of the cause and location of a failed, (leaking) spill container or the configuration of the spill container, my invention provides means for repairing these spill containers. 
         [0025]      FIG. 3  is a cross section view of the components of a liner  30 . When the liner top  12 , is joined to the liner bottom  10 , the liner  30  is created. In some instances the liner  30  may be manufactured as a single component. Such a liner  30  could be fitted into  FIG. 2 . and function as designed. However most spill containers have a mouth opening smaller than the diameter of the bellows  20  section of the spill container as shown in  FIG. 1 . It is preferred that the liner  30  fit the interior profile of the spill container as liner  30  needs to be as large as possible so as to not unduly reduce the capacity of the spill container. Large “collapsing core” molds could be made to manufacture the various liners in one piece. It is preferred however, to manufacture the liner  30  from two or more segments. It is preferred to manufacture a separate liner bottom  10  and a separate liner top  12  and join the components by a suitable connecting method. In that manner the tooling required to make all the configurations of liners required can be minimized. The bottom from one liner  30  and the top from another liner  30  may be joined to form a third liner  30 . In the preferred embodiment, a bonding agent is used to bond the liner  30  to the snow plow ring  22  and to the tank riser  28 . While bonding is not required it is a highly recommended procedure that assures a long lasting product requiring little maintenance. The liner  30  material should be chemically resistant to the liquids to be encountered. The liner  30  should be able to be bonded a to the mating spill container and tank riser  28  surfaces as well as being able to be bonded together. One such material that has been tested by Underwriters Laboratories for use in secondary containment applications at fueling sites is Pellethane 2355-85ABR available from Dow Chemical Co. Additionally the liner  30  may have a coating  36  applied. A suitable coating  36  material is used to make the liner  30  chemically more resistant to the specific fluids to be contained. A polysulfide liquid is available from Diversified Products Manufacturing Inc., part number DBF II. It is a suitable material for applications where motor fuels are to be encountered. Polysulfide has been used for years to coat the inside of fuel cells in aircraft. 
         [0026]      FIG. 3  also shows an expanding compression ring  14 . While the expanding compression ring  14  is not required, the preferred embodiment uses the expanding compression ring  14  to apply mild pressure to bonding surface A  18  while the bonding agent is curing. After the bonding agent has cured, approximately 30 minutes in the preferred embodiment, the expanding compression ring  14  may be removed and used on the next installation. The expanding compression ring  14  may be made of any suitable material, plastic, metal or wood etc. 
         [0027]    The band clamp  16  in  FIG. 3  is used to tighten the liner  30  to the tank riser  28 . In the preferred embodiment the liner  30  is bonded to the riser then clamped to hold the liner  30  to the tank riser  28  while curing. The band clamp  16  while not essential is preferred. Any properly sized all stainless band clamp  16  in the market today will work for this application. Such a clamp is available from Norton Industries Inc., part number 035BR072-04, which fits 4″ tank risers. 
         [0028]      FIG. 4  shows the cross section of a spill container to be repaired and the areas requiring preparation prior to the installation of the liner  30 . The liner  30  may be bonded to the spill containment snow plow ring  22  at bonding surface A  18 . A second bonding surface B  34  is located on the tank riser  28 . These surfaces, if bonded, require proper preparation for the bonding agents to be used. The preparation and bonding agent used is a function of the materials selected to manufacture the liner  30 . In the preferred embodiment a Methyl Methacrylate is used. One such material is manufactured by available from Weld On, part number SS218 Stock # 30110. It is anticipated that other bonding agents will be found that will perform as well as or better than the currently preferred product. Surface preparation for the preferred embodiment includes sanding bonding surface A  18  then cleaning with tetrachloroethylene. When the surfaces are clean and dry the bonding agent may be applied to the mating surfaces to be bonded. The drain valve  26  must be removed and the resulting hole plugged. Use a plug  40  with the same thread pattern as the removed drain valve  26 . The plug  40  may be made of any material as it will be covered with a fill  38  during the installation process. 
         [0029]      FIG. 5  is a cross section of the bellows  20  style spill container where fill  38  has been added to cover the irregular shape of the bottom of the spill container. It should be noted that the connection between the spill container and the tank riser  28  varies by manufacturer. Most spill containers have bolt heads that connect the bellows  20  to the body and/or some sort of compression coupling or screwed coupling or other means for joining the tank riser  28  to the spill container. These connection methods create an uneven surface at the bottom of the spill container. In order to make the repair easier, it is recommended that the uneven bottom of the spill container be leveled. The preferred embodiment of the invention uses a liquid form of polysulfide to fill  38  the bottom to a level above any irregularities encountered. The preferred polysulfide is a two part chemical that when mixed forms a permanent barrier to most fuels and bonds to metal and the liner  30  materials in the preferred embodiment. The preferred fill  38  material is available from Diversified Products Manufacturing Inc., Oroville, Calif. part number DBF II. While the fill  38  is not mandatory it is recommended in the preferred embodiment. Any liner  30  not using a fill  38  is subject to unnecessary wear and premature failure. Manufacturing a unique liner  30  for each manufacturer of spill container may be undertaken. However the tooling for this process would be unduly costly. 
         [0030]    The cross section of  FIG. 5  shows the spill container ready for the application of the bonding agent to the tank riser  28  and the subsequent installation of the liner  30 . The surface of the tank riser  28  located under the clamping area should be cleaned prior to applying the bonding agent. Typically the tank risers are steel. When the riser is clean, apply the bonding agent to the bonding surface B  34  for approximately 1½″ above the polysulfide fill  38 . The entire perimeter of the tank riser  28  should be covered with the bonding agent. 
         [0031]      FIG. 6  is a cross section view of the liner  30  ready to be installed in a bellows  20  style spill container. In this embodiment, the liner top  12  and liner bottom  10  are shown as one piece. The liner  30  may be made up of one, two pieces, as shown in the preferred embodiment, or as many pieces as necessary to match the liner  30  to be spill container. In the preferred embodiment, the liner top  12  and liner bottom  10  and are joined together using a solvent welding process. The material used to manufacture the liner  30  is dissolved in a strong solvent, such as tetrahydrofuran, forming a pregnant solution. When this solution is applied to the mating and preferably overlapping surfaces of the liner top  12  and liner bottom  10 , a solvent weld is created. The process of solvent welding is common knowledge and need not be reiterated here. The welded seam thus created is as strong as the liner top  12  or liner bottom  10 . The liner  30  is collapsed when installed into the spill container shown in  FIG. 6 . 
         [0032]      FIG. 7  is a cross section view of a bellows  20  style spill container with the liner  30  the installed. The top of the liner  30  should mate to the inside of the spill container&#39;s snow plow ring  22 . The application of the bonding agent to bonding surface A  18  is applied at this time by folding down the collapsible liner  30  and running a bead of the bonding agent around the perimeter of the liner top  12  and mating surface of the snow plow ring  22 . The top of the liner  30  may be held in place by an expanding compression ring  14  while the bonding agent cures. After curing of the bonding agent, the repair of the spill containment manhole is complete. 
         [0033]    Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention. 
         [0034]    Having thus described the invention, what is desired to be protected by Letters Patent is presented in the subsequently appended claims.