Title:
Flat-sided single-wall attached sump collar
Kind Code:
A1


Abstract:
An attached sump collar for an underground storage tank (UST) provides a flat surface for a connection with a fixture from the UST. Connecting the fixture at a flat surface of the sump collar advantageously improves the efficiency of the seal between the collar and the fixture. The connection may be made at a nearly right angle. In one embodiment, the seal is liquidtight, and the collar is used in combination with a liquidtight riser.



Inventors:
Burwell, John (Eagan, MN, US)
Application Number:
11/589917
Publication Date:
05/01/2008
Filing Date:
10/31/2006
Primary Class:
Other Classes:
52/741.12
International Classes:
B65D90/10
View Patent Images:
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Primary Examiner:
THOMAS, KAREEN KAY
Attorney, Agent or Firm:
MUETING RAASCH GROUP (MINNEAPOLIS, MN, US)
Claims:
1. 1-16. (canceled)

17. An underground storage tank assembly, comprising: an underground storage tank comprising one or more tank walls defining an interior volume of the underground storage tank, wherein the underground storage tank defines at least one opening to the interior of the underground storage tank; and a collar surrounding the at least one opening, wherein the collar comprises one or more collar wall surfaces extending from the one or more tank walls to surround the at least one opening, wherein the one or more collar wall surfaces comprise at least one flat side wall surface.

18. The underground storage tank assembly of claim 17, wherein the collar is molded as an integrated component of the underground storage tank.

19. The underground storage tank assembly of claim 17, wherein the collar is attached to the underground storage tank, and further wherein the attachment of the collar to the underground storage tank is a liquid tight attachment.

20. The underground storage tank assembly of claim 17, wherein the collar is a single-walled collar.

21. The underground storage tank assembly of claim 17, wherein the at least one flat side wall surface has a height such that a fixture can penetrate the at least one flat side wall surface.

22. The underground storage tank assembly of claim 17, wherein the assembly further comprises a fixture that penetrates and forms a connection with the at least one flat side wall surface.

23. The underground storage tank assembly of claim 22, wherein the fixture penetrates the at least one flat side wall surface at a right angle or at a nearly right angle.

24. The underground storage tank assembly of claim 17, wherein the assembly further comprises a riser attached to a top edge of the collar.

25. The underground storage tank assembly of claim 17, wherein the one or more collar wall surfaces of the collar comprise a plurality of flat wall surfaces surrounding the at least one opening.

26. The underground storage tank assembly of claim 17, wherein the one or more collar wall surfaces of the collar comprise a plurality of flat wall surfaces, wherein the plurality of flat wall surfaces provide the collar with a polygonal cross-section over at least a portion of a height of the collar.

27. A method of installing an underground storage tank assembly, wherein the method comprises: providing an underground storage tank comprising one or more tank walls defining an interior volume of the underground storage tank, wherein the underground storage tank defines at least one opening to the interior of the underground storage tank; providing a collar for the underground storage tank surrounding the at least one opening either before or after the underground storage tank is positioned in an excavation site, wherein the collar comprises one or more collar wall surfaces extending from the one or more tank walls to surround the at least one opening, wherein the one or more collar wall surfaces comprise at least one flat side wall surface; and forming a connection between a fixture and the at least one flat side wall surface of the collar.

28. The method of claim 27, wherein providing a collar for the underground storage tank comprises molding the collar as an integrated component of the underground storage tank.

29. The method of claim 27, wherein providing a collar for the underground storage tank comprises attaching the collar to the underground storage tank.

30. The method of claim 27, wherein the fixture penetrates the at least one flat side wall surface at a right angle or at a nearly right angle.

31. The method of claim 30, wherein the fixture extends horizontally through the at least one flat side wall surface.

32. The method of claim 27, wherein forming a connection between the fixture and the at least one flat side wall surface further comprises testing the connection to determine if the connection is liquid tight.

33. The method of claim 27, wherein the method further comprises attaching a riser to a top edge of the collar.

34. The method of claim 27, wherein the one or more collar wall surfaces of the collar comprise a plurality of flat wall surfaces surrounding the at least one opening.

35. The method of claim 27, wherein the one or more collar wall surfaces of the collar comprise a plurality of flat wall surfaces, wherein the plurality of flat wall surfaces provide the collar with a polygonal cross-section along at least a portion of the height of the collar.

36. The method of claim 27, wherein the collar is a single-walled collar.

Description:

BACKGROUND

1. Technical Field

This application relates generally to an attached sump collar for an underground storage tank, in particular, a flat-sided collar that accommodates pipe penetrations.

2. Background of the Technology

Storage tanks are used to store a wide variety of materials, such as gasoline, petroleum products, manufacturing liquid waste, sewage and other environmentally hazardous materials. Storage tanks are often located underground to conserve space. Concern about leaks in underground storage tanks (USTs) has lead to the adoption of a variety of products and methods for leak detection and secondary containment. For example, USTs are now typically constructed with materials such as fiberglass reinforced plastic (FRP) for improved resistance to corrosion and rusting. USTs also can be double-walled or triple-walled, where the tank is provided with a surrounding wall(s) to contain any fluid that leaks from the tank until repairs can be made. The annular space between the walls may contain alarm devices of a variety of designs to detect the passage of liquid from the interior tank or through the exterior wall(s). Multi-walled USTs manufactured by Xerxes Corporation, the assignee of the present application, have proven reliable over prolonged use for many years. Piping and attached containment sumps also may use double walls, as described, for example, in application Ser. No. 10/796,198, entitled “Double Walled Containment Sumps,” assigned to Xerxes Corporation.

A UST typically is provided with a manway, which allows access to fill or repair the tank. To access the interior of the tank, the manway generally is provided with a removable lid mounted on a flange. A variety of fixtures, e.g., filling devices, submersible pumps and the like, can run through the manway lid.

Access to the manway may be provided by a containment riser that surrounds the manway and extends from the UST to a point just below the ground level of the installation site of the UST. Access from the ground level to the top of the riser is accomplished at a street box having a removable manhole cover. Where the riser is intended for secondary containment, the containment system is typically called a sump. In this case, an alarm is frequently provided to detect the accumulation of liquid in the riser.

Since USTs are buried usually to a standard depth, the riser providing access to the manway likewise is typically a standard length. The riser may be fabricated from such materials as steel, polyethylene or fiberglass reinforced plastic (FRP). The riser may be attached directly to the outer wall of the tank by a variety of means known in the art, e.g. by “glassing” when the riser is made of FRP. The riser may be attached to the tank at the factory or at the installation site. Installation at the factory is preferred because the integrity of the seal between the riser and UST can be better controlled and the potential escape of harmful chemicals into the environment can be avoided. Given the combined height of the riser when attached to the UST, transporting a UST with a riser in place may be problematic if the transportation route to the installation site crosses under bridges, etc.

For these reasons, a sump collar first can be attached to, or molded as an integral part of, the UST. The top of the sump collar is designed to be easily mated with a riser, facilitating attachment of the riser in the field at the site of installation of the UST. The riser can be attached to the collar with adhesives, for example, creating a tight seal and avoiding release of harmful chemicals into the environment. Various means of attaching the collar to the UST and the riser to the collar are described in application Ser. No. 10/801,854, “Reverse Flange Collar Adapter and Reverse Flange Collar,” assigned to Xerxes Corporation and incorporated herein by reference.

The water table in many parts of the country may rise for extended periods to a height exceeding all or part of the riser. For that reason, Xerxes Corporation provides a watertight riser, described in U.S. Pat. No. 5,595,456, “Water-Tight Riser for Underground Storage Tank Manway,” incorporated herein by reference. Risers, however, are typically penetrated by pipes or other fixtures leading horizontally away from the manway, whether the riser is attached directly to a UST or to a collar. Connections between the pipes or other fixtures and the round wall of the riser are difficult to seal, and care must taken to ensure that these connections are watertight and provide some measure of leak resistance, especially where the water table exceeds the height at which the riser is penetrated by a fixture. Accumulated liquid within the riser otherwise could impede access to the manway or compromise the integrity of the various fixtures used with the UST.

SUMMARY

The present invention addresses this and other needs by providing an attached flat-sided single-walled sump collar. Fixtures from the manway penetrate and connect with the collar at the flat wall surface, advantageously providing a more efficient seal around the connection between the fixture and the wall. In one embodiment, the fixture penetrates the flat wall surface at a nearly right angle. In another embodiment, the connection between the fixture and the flat wall surface is liquidtight.

Accordingly, in a first aspect of the invention, a UST assembly comprises a UST having a manway, a fixture extending from the UST through the manway, and an extended single-walled sump collar attached to the UST and surrounding the manway. The collar comprises a flat wall surface, i.e., it may be polygonal, and the fixture penetrates and connects to one of the flat wall surfaces of the collar. The fixture may penetrate the flat wall surface of the collar at a right angle or at nearly a right angle, and it may penetrate the collar horizontally. The assembly further may comprise a riser attached to the collar, where the riser extends to a street box at ground level and where the riser is not penetrated by a fixture extending from the UST. The attachments between the riser, collar and UST and the connection between the fixture and the flat wall surface of the collar may be liquidtight.

A second aspect of the invention provides a method of installing the UST assembly of the first aspect of the invention. The method comprises placing the UST in an excavated site and partially backfilling the site to cover the UST except for the manway and the attachment site of the flat-sided single-walled collar. In one embodiment, the method further comprises attaching the single-walled flat-sided collar to the attachment site on the UST, which may be done before or after backfilling. In another embodiment, the collar is molded as part of the UST. The method further comprises connecting a fixture extending from the UST to the flat wall surface of the flat-sided collar, where the fixture may penetrate the wall at a nearly right angle, and where the connection may be watertight. The flat-sided collar may be attached with adhesives, fiberglass, solder, or the like. The method may further comprise attaching a riser to the collar. The method additionally may comprise testing the attached flat-sided single-walled collar for water leaks.

The flat-sided single-walled collar may comprise a plurality of flat wall surfaces to facilitate alignment between the flat wall and fixture(s). In the preferred embodiment, the collar is polygonal in cross-section.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 depicts various aspects of a UST installation, using a conventional circular collar and riser.

FIG. 2 depicts an embodiment of a flat-sided single-walled collar that provides a flat wall surface where a fixture penetrates the side of the collar.

FIG. 3A, FIG. 3B, and FIG. 3C depict three representative forms of attachment of a riser to the top edge of the flat-sided single-walled collar depicted in FIG. 2.

DETAILED DESCRIPTION

The invention provides a flat-sided single-wall collar for a UST, where a fixture from the UST penetrates the flat wall surface of the flat-sided collar. Connecting the fixture at a flat wall surface advantageously improves the efficiency of the seal between the fixture and the wall. The connection between the fixture and flat wall surface may be made at a nearly right angle. In one embodiment, the flat-sided single-wall collar helps provide liquidtight protection for the manway.

FIG. 1 illustrates a conventional underground storage tank installation, e.g., a gasoline tank installation, including a riser 3 and double-walled piping 20. The UST 1 may be single-walled, double-walled, or triple-walled and fabricated, for example, from fiberglass. The UST 1 is secured by a pair of retaining straps 5 attached to a pair of deadmen 6 (one of which is visible in FIG. 1) to prevent flotation of the UST 1 where the water table is high. The deadmen 6 may be of a conventional type or may be of the type described in U.S. Pat. No. 6,786,689, entitled “Low Profile Deadman and Method for Shipping the Same with a Tank” and assigned to Xerxes Corporation. Other types of retaining systems, including slabs above and below the UST, are known in the art. Various means for attaching the UST to a deadman also are known, as described, for example, in co-owned U.S. Pat. No. 7,028,967, entitled “Tank Retaining System.”

The UST 1 in FIG. 1 is depicted with a conventional collar 2 attached to the riser 3. The conventional collar 2 is not sufficiently high to allow double-walled pipe 20 and other fixtures to penetrate the collar 2. The collar 2 and riser 3 surround a manway 14 covered by a manway cover 14a. Various possible attachments between the collar 2, riser 3 and manway 14 are described in application Ser. No. 10/801,854, filed Mar. 17, 2004, “Reverse Flange Collar Adapter and Reverse Flange Collar,” assigned to Xerxes Corporation and incorporated herein by reference.

A riser cover 23 sits atop the riser 3. The riser cover 23 includes a removable domed cover 24. The collar 2, riser 3, riser cover 23 and domed cover 24 together may form a watertight containment sump 30. An access way 25, also known as a street box, provides access to the domed riser cover 24 via a ground level access way cover 10. The access way 25 and access way cover 10 are not part of the sump and are not necessarily watertight.

The double-walled UST 1 may include a hydrostatic monitoring system 4, which monitors the level of a monitoring fluid, typically brine, between the two walls of the double-walled UST 1. The hydrostatic monitoring system 4 includes a monitoring sensor 9 connected to a communication module 9a through tube 17. The tube 17 is accessible via access cover 16. The interior of the UST 1 may be filled from ground level by removing the cover 11a from the spill containment sump 11, which provides access to the fill cap 12 covering the fill tube 13.

A level probe 7 is disposed within the sump 30 and passes through the manway cover 14a to monitor the level of fluid within the UST 1. A single-walled vent pipe 19 is connected to the housing for the level probe 7 and passes through the wall of the riser 3 to provide venting for the UST 1. Also disposed within the sump 30 is an extractor assembly 21, which is connected through the manway cover 14a to ball float 15 in the interior of UST 1.

A double-walled pipe 20 carries gasoline from the UST 1. The double-walled pipe 20 also passes through a side of the riser 3. The interior wall 26 of the double-walled pipe 20 is connected, via a flex connector 27, to a pipe 18 passing through the manway cover 14a to the interior of the UST 1. The space between the outer wall 28 and the inner wall 26 of double-walled pipe 20 may be in fluid communication with the sump 30, so that fluid leaking from the interior wall 26 of the double-walled pipe 20 will be contained by the outer wall 28 and transported to the sump 30 for containment. A sensor 8 detects any fluid in the sump 30 and triggers an alarm system (not shown in FIG. 1). Those of skill in the art will understand that the foregoing installation is one of many possible installations and that the invention is not limited to any particular type of installation.

An example of the flat-sided single-walled collar according to the invention is depicted in FIG. 2. The collar 2a is attached to the UST 1 and surrounds a manway 14, which is not depicted in FIG. 2. Various fixtures, such as a double-walled pipe 20 and/or a vent pipe 19, penetrate the side of the collar 2a (also not depicted in FIG. 2). A riser 3 of the type depicted in FIG. 1 may be attached to the top of the collar 2a so that the riser extends from the top of the collar 2a to an access way 25 at ground level. The collar 2a may be about four feet in diameter to accommodate fixtures and to facilitate access to the manway 14. In one embodiment, the collar 2a and the riser 3 form a liquidtight containment sump 30.

The collar 2a comprises a flat wall surface, as depicted in FIG. 2. The use of a flat wall surface advantageously improves the seal formed between the collar wall and a penetrating fixture(s). The fixture(s) preferably penetrates the collar 2a at close to a right angle to the flat wall surface. In a preferred embodiment, all or part of the side of the collar 2a is polygonal. The collar may be polygonal in cross-section over all or part of its height, provided only that a fixture penetrates the collar 2a wall at a flat surface. A regular polygon is illustrated in FIG. 2, but it is unnecessary for the polygon to be regular. It is preferable for the polygon to have as many sides as possible to increase the ease in aligning a fixture with a flat wall surface of the collar. The number of flat sides of the collar 2a is also determined by the final width of each side, which must be sufficiently wide to allow for a connection between the wall and the fixture.

The top edge or portion of the collar 2a may be round to facilitate mating the collar 2a with a riser 3. As depicted in FIG. 2, the circumference of the collar 2a is inwardly recessed, providing a ledge next to the recess. FIG. 3A provides a more detailed depiction of the top edge of the collar 2a, showing the recess toward the center axis of the collar and the resulting ledge 31, as well as the position of a sealant 32 before and after attachment to a riser 3 (left and right figures, respectively). FIG. 3B shows an outwardly recessed top edge of the collar 2a, again providing a ledge 31 on which the riser 3 may rest. Other means of attachment are known in the art. FIG. 3C, for example, shows a top edge of the collar 2a that comprises a groove 33 around the circumference of the collar 2a into which the bottom edge of a riser 3 or other top piece may be inserted. The collar 2a is attached directly to the UST 1 or to the manway 14. In this latter embodiment, the bottom edge of the collar 2a curves toward the center axis of the collar 2a to form a circular aperture that is about the same diameter as the manway 14. In such an embodiment, the collar 2a may be attached by fasteners to a flange on a collar of the manway 14, for example. Such attachments are described in application Ser. No. 10/801,854, filed Mar. 17, 2004, which is incorporated herein by reference.

When the collar is attached to the UST at the factory, the collar extends the height of the UST system somewhat during transportation. The increase in overall height is no more than needed to accommodate fixtures, so the increased height generally is not expected to increase significantly the difficulty in transportation. In one embodiment, the collar is molded as an integrated component of the UST during the fabrication of the UST. Alternatively, the collar may be attached to the UST in the field before or after the UST is partially covered by backfilling. The collar may be attached with adhesives or a fiberglass lay-up, for example. The collar may be tested after it is attached to the UST to ensure that the seal between the collar and the UST is watertight.

Fixtures running horizontally from the manway of the UST run through holes made in the flat wall surface(s) of the flat-sided collar, and connections are made between the wall and fixture(s) using conventional techniques. Because of the improved sealing characteristics offered by the present flat-sided collar, the connection is easily and advantageously made liquidtight. In one embodiment, the connection between the fixture(s) and the wall surface is made at a right angle or at nearly a right angle. A riser or several riser segments may then attached to the flat-sided collar, so that the height of the system nearly reaches ground level. In one embodiment, the collar and riser form a liquidtight connection. The various connections can be tested by filling the riser and collar with water and examining the outside of the system for water or the water level in the connected riser and collar. The backfilling is then completed so that the sides of the collar, or collar and riser, are supported by backfill, and a street box is set over the riser cover to provide access to the UST.

While the foregoing specification teaches the principles of the present invention, with examples provided for the purpose of illustration, it will be appreciated by one skilled in the art from reading this disclosure that various changes in form and detail can be made without departing from the true scope of the invention.