The present invention relates to underground liquid fuel storage tanks and, more particularly, to new and improved covering system for underground fuel storage tanks.
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.
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.
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:
With reference to
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, & C below are in the alternative.
Installation steps can generally include:
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.
Number | Name | Date | Kind |
---|---|---|---|
1889056 | Blanchard | Nov 1932 | A |
3017721 | Wasserman | Jan 1962 | A |
4703592 | Sampson et al. | Nov 1987 | A |
5311966 | Daniels | May 1994 | A |
5650065 | Sewell | Jul 1997 | A |
5951200 | Barton | Sep 1999 | A |
5966876 | Neathery et al. | Oct 1999 | A |
6527476 | Pettesch | Mar 2003 | B1 |
20020124490 | McCarthy | Sep 2002 | A1 |