TECHNICAL FIELD

The present invention relates generally to underground piping systems for transmitting hazardous fluids, such as, gasoline from an underground storage tank to fuel dispensing units typically found at gasoline service stations. More specifically, the present invention relates to improvements in so-called "flexible entry boot assemblies" used in these systems to connect the flexible underground piping systems to pumping apparatus housed in underground sumps or the like.

BACKGROUND ART

In recent years there has been a national mandate to protect ground water from hazardous liquid contamination. As a result, there has been federal, state and local legislation created throughout the country requiring stringent regulation on the manner in which hazardous liquids are stored and piped in underground applications. These new regulations require the replacement of leaking underground storage units, storage tanks and associated underground piping. These regulations have also established new design criteria to prevent future tanks and piping from leaking into the environment.

Prior to any environmental regulations, there was no concern about installing a tank sump under the street manhole which provided access to the tank and its pump and plumping components. It was only necessary was to provide a barrier to prevent the surrounding backfill materials from entering the area directly below the street manhole. This was typically accomplished by installing a short section of large diameter corrugated pipe that was open at the top and bottom.

When fiberglass underground storage tanks entered the market, some years ago, a problem arose when the unsecured corrugated pipe sections began to damage the top of the tank due to tank and ground movement. It was at this time that attention was directed to designing a backfill barrier which

would not damage the tank. The fiberglass tank manufacturers introduced a flange mounted backfill barrier which was directly connected to the tank. At this time there was no thought to keeping out water or containing leaking product. Therefore, no provisions were made for sealed pipe and conduit entries or keeping out surface water from leaking down through the street manhole.

Backfill barriers were replaced with environmentally safe tank sumps in recent years. These sumps addressed the need to be liquid tight and made of materials which are corrosion resistant and chemically compatible with the liquid products being stored. The new sumps also featured, enclosed bottoms, pipe and conduit seals, and water tight tank adapters which provide connections to the tank. The two piece construction of the tank adapter allowed for easier installation in deep tank burials. These new tank sumps were far from being the practice since pipe and conduit entry seals were difficult to install in a liquid tight manner. Many of these sumps have collapsed due to external backfill and high groundwater pressure because of their structural design. Most of these sumps are made of rotationally molded polyethylene or glass reinforced plastic (fiberglass) , both being a non-corrosive material.

With the introduction, of a new environmentally safe tank sump, has come the development of a new type of sump called the "dispenser sump". The sumps are of a different design but

serve a similar purpose. They are installed under the fuel dispenser to provide a means of secondary containment for the dispenser plumbing and the underground piping connections located directly below the dispenser. These dispenser sumps are available in both shallow and deep versions.

Subterranean piping systems, which are typically found at service stations, connect the remote underground storage tank to one or more above ground fuel dispensing units. At each of these connection locations are found access enclosures which provides surface access to these piping connections and other equipment such as tanks' pump, valves and other plumbing devices.

The underground storage and fuel dispensing system has been determined to be a source of environmental pollution, as well as a safety hazard because of product leakage into the surrounding earth. All components of that storage and dispensing system should be designed in such a manner that they prevent any leakage into the environment. Access enclosures located at the tank and under the dispensing unit provide a means of secondary containment for part of the entire system.

These access enclosures should be of such a design that they are liquid tight preventing ground and surface water from entering the enclosure, and containing leaking product from escaping the enclosure into the surrounding environment. They

should also be made of a material which is resistant to corrosion and deterioration. They should also be of sufficient strength to withstand external pressure from surface loads, backfill pressure, and high ground pressures. They should also be designed and installed so that they flex or shift in such a manner that they do not damage the top of the tank as a result of tank, ground or surfaced movement. They should provide a means of effectively sealing all conduit and pipe penetrations into the sump. They shall provide a mean for liquid tight and secure connections to the tank and dispensing island.

Boots for sealing the conduits and pipe at the sump locations are not new per se. However, the present designs have several disadvantages and drawbacks. There a number of products available which provide a means of effectively sealing all conduit and pipe penetrations into the sump. These products meet many of the above design requirements but for one reason or the other are deficient.

One of the areas in which these sumps are deficient is in the manner in which they deal with pipe and conduit entries into the sump. The nature of the problem is that pipe conduit does not always enter or exit the sump in a head on direction. Because of the congested plumbing configurations inside the sump, the exit direction of the pipe or conduit is many times at an angle in relation to the sump wall. Angled entries and exits present a difficult installation problem and often make

it impossible to achieve a liquid tight seal using conventional pipe and conduit seals.

Different manufacturers offer a variety of seals and sump configurations which address pipe and conduit penetration. The most popular type of seal being used is a rubber grommet which is available in a variety of pipe and conduit sizes. This allows a hole to be drilled in any desired location of the sump wall accommodating a pipe or conduit. The effectiveness of this product depends on a clean and even hole being drilled in the sump wall and the pipe or conduit entering the exiting the sump in a head on direction. Many of the sumps that are leaking today are fitted with these type of seals. It is noted that once installed and buried it is virtually impossible to fix a leaking grommet. Accordingly, this is a critical seal in these systems.

Another manner of sealing pipe and conduit entries is to provide integral molded cuffs in the sump located in fixed locations on the sump wall. These cuffs generally face inward so that they are accessible after burial. The problem with this type of design is that they fix the location of all pipe and conduit entries or exits. This means the external pipe and conduit routing layout must be exact, and the internal plumbing configurations inside the sump must be designed in such a manner that the pipe and conduit exit at these fixed locations. These internal cuffs are rigid and therefore do not allow for

angled pipe and conduit exits. Another problem with these fixed internal cuffs is that they must be very large in diameter to accommodate a variety of pipe and conduit diameters. These are three types of internals cuffs available on different types of tank sumps. The first type of cuff is available on fiberglass sumps and are designed to be sealed to fiberglass piping by means of applying a thermoset resin and glass matting. The second type of cuff is available on rotationally molded polyethylene sumps are designed to seal the pipe or conduit by means of a rubber seal and band clamp. The third type of cuff is available on steel sumps and use a rubber reducer boot to seal from the outside of the cuff down to the outside of the pipe or conduit.

In summary, the present designs do not provide the optimum seal between the flexible piping and the sump and the desired and necessary radial and axial flexibility to provide an effective seal at this juncture and a relatively easy trouble free means for securing the pipe connections inside the sump.

DISCLOSURE OF THE INVENTION

With the foregoing in mind, it is an object of the present invention to provide a flexible entry boot assembly characterized by novel features of construction of arrangement which is easy and quick to assemble and provides a tight hermetic seal between the opening in the sump and the conduit and which allows limited radial and axial displacement of the pipe assembly in the boot. This facilitates easy assembly of the pipe to other equipment housed in the sump and also allows a degree of displacement during use which may be occasioned by change of flow conditions in the piping system.

The flexible entry boot assembly of the present invention allows for slight ovality of the circular opening in sump within which the boot is mounted to support the piping system and still provide tight bi-axial and radial seals insuring against leakage. Furthermore, in accordance with the present invention there are no fastening means exposed to the ambient environment outside the sump which could become contaminated.

The boot assembly of the present invention ensures the integrity of the pipe connections, not only to the sump, but also to the equipment within the sump and thereby achieves the overall object of these systems, that is, ensuring against hazardous liquid contamination of the environment.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other objects of the present invention and the various features and details of the operation and construction thereof are hereinafter more fully set forth with reference to the accompanying drawings, wherein:

Fig. 1 is a schematic view showing a typical underground piping system incorporating a flexible entry boot in accordance with the present invention;

Fig. 2 is an enlarged transverse sectional view showing a flexible entry boot in accordance with the present invention supporting the pipe in the base of a sump;

Fig. 3 is view taken on lines 3-3 of Fig. 2 with parts broken away to show parts of the boot assembly more clearly;

Fig. 4 is transverse sectional view of a boot assembly in accordance with the present invention;

Fig. 5 is side elevational view of boot assembly shown in Fig. 4;

Fig. 6 is a side elevational view of a locking ring for securing the boot assembly;

Fig. 7 is a sectional view taken on lines 7-7 of Fig. 6;

Fig. 8 is a view similar to Fig. 6 showing the locking ring coiled;

Fig. 9 is a sectional view taken on lines 9-9 of Fig. 8;

Fig. 10 is a sectional view of the boot assembly with the sleeve portion in an inverted position to facilitate assembly of the locking ring;

Fig. 11 is a side elevational view showing the tool for rotating the locking ring to a locked positioned;

Fig. 12 is a side elevational view showing the locking ring fully in place; and

Fig. 13 is a perspective view of a tool for assembling the locking ring of flexible entry boot assembly of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION

Referring now to the drawings and particular to Fig. 1 thereof, there is illustrated a typical pumping system incorporating a secondary containment means for preventing hazardous fluids, such as, petroleum products from leaking into the environment. The basic components of the pumping system include a storage tank for underground storage of a petroleum product such as gasoline, a submersible pump assembly 12 housed in a collection sump 16. The pump 12 is connected through a piping system generally referenced 20 to a standard product dispenser 22. As best illustrated in Fig. 2 the conduit or pipe 20 passes through an enlarged generally circular opening 28 in the wall of the sump base 24 and is connected to the submersible pump by standard couplings or the like.

A flexible entry boot assembly in accordance with the present invention and generally designated by the numeral 30, is provided to support the pipe assembly 20 in the sump base 24. The flexible boot assembly 30 comprises a boot member 32 made of a flexible material, such as, rubber and a locking ring 34 for sealingly attaching the boot 32 to the sump wall surrounding the opening 28 in the sump base.

Considering first the boot member 32, the boot comprises of an elongated generally cylindrical pipe engaging sleeve

section 36 having predetermined diameter D _s slight greater than the diameter D of the pipe to snugly embrace the pipe 20, an annular ring-like seal section 40 of frusto-conical cross section having a radially directed circumferentially extending slot 42 extending inwardly from the outer face 40 _Q of the seal ring 40 to define a pocket 46 embracing the inner and outer walls 24 _j and 24 _Q of the sump base surrounding the pipe opening 28. The diameter D _s of sleeve section is smaller than the diameter D ₀ of the pipe opening 28 in the base of the sump to allow for the limited universal movement of the sleeve section and pipe relative to the sump desirable to permit angled entry of the pipe to the interior of the sump and permit greater ease and flexibility in assembly of the pipe to other elements of the septic housed in the sump. The slot 42 defines two axially spaced flanges 44 _j and 44 _Q which straddle the wall of the sump surrounding the opening 28 and form the pocket 46 within which the inner and outer wall sections of the sump surrounding the opening 28 engage or nest. The seal section 40 of the boot is connected to the sleeve section 36 by a radially outwardly directed flexible wall portion 50 extending between the outer terminal end of the annular seal section 40 and the outer peripheral edge of the flange 44 _Q of the seal ring 40. The flexible connecting wall 50 as illustrated is frusto-conical having an inwardly dished front face 52. The inner axial end of the sleeve 36 is provided with a pair of axially spaced radially outwardly directed ribs 60 and 62 defining a seat 64

for a clamping ring 66 for firmly securing the boot to the pipe assembly as explained in more detail below.

The locking ring 34 as best illustrated in Figs. 6-8 is a split ring or open annulus preferably made of a semi-rigid but somewhat flexible plastic material, such as polypropylene. The ring 34 is of generally U-shaped cross-section comprising a generally cylindrical base 70 of a predetermined width W and a pair of radially outwardly directed side walls or flanges 72 and 74 which are slightly outwardly flared as shown. The cross sectional shape of the locking ring 34 complements the frusto- conical shape of the sealing ring 40 to provide the desired triple sealing function described in more detail below. Accordingly, the locking ring 34 may also be described as being of a frusto-conical shape. The side walls are provided with a series of circumferentially equi-spaced slits 70 ^a which extend inwardly from the outer peripheral edge of the side walls to a point adjacent the base 70 to facilitate coiling and uncoiling of the locking ring in the manner described in more detail below.

The cross-sectional configuration of the locking ring 34 complements the outer configuration of the boot seal section 40 and is dimensioned in relation thereto to provide a bi¬ directional axial seal and radial squeezing action of the sealing ring with the wall of the sump opening upon assembly of

the locking ring in the manner described below. More specifically, the widthwise dimension ₂ of the channel 71 of the locking ring is slightly smaller than the cross-wise dimension W3 of the sealing ring 40 at a complementary point when assembled to provide this squeezing action. Moreover the diameter D _m of the locking ring when it is in the fully assembled position is slightly greater than the diameter D _s of the inner peripheral surface of the seal 40 in the relaxed state. This produces a squeezing action in the radial direction when the parts are fully assembled. More specifically, the base of the locking ring in the fully expanded condition creates a radial squeezing force on the sealing ring 40 pressing it against the opening 28 in the sump when the locking ring is fully expanded.

The boot and the locking ring are of a predetermined configuration and dimensional relationship to provide a two way axial seal of the boot relative to the sump wall surrounding opening 28 and a tight radial seal about the periphery of the opening 28 in the sump. To this end, the width _b of the base of the locking ring is preferably slightly smaller than the width Wtø _s of the boot and the distance W ₂ between the flanges 72 and 74 of the locking ring at their outer terminal ends is preferably smaller than the cross-sectional dimension 3 of the annular seat of the boot in the assembled position shown in Fig. 3 to provide the axial squeezing force on both sides of

the seal against the wall of the sump surrounding the opening 28.

Consider now the application of a flexible entry boot assembly made in accordance with the present invention in a sump. The boot can be assembled from exteriorly of the sump by simply squeezing the annular seal section 32 until the wall of the sump surrounding the opening 28 engages loosely in the pocket 46 in manner shown in Fig. 10. With the sleeve 36 in an inverted position (Fig. 10) , the coiled locking ring 34 is then positioned interiorly of the annular seal section of the boot in the position shown in Fig. 10. The assembly tool 80 is then used to uncoil the locking ring by placing it interiorly of the locking ring so that one of the blades or fins 82 engages the projection or rib 86 at one terminal end of the locking ring. The tool engages rib 86 projects radially inwardly below the circular trace C of the inner peripheral surface of the base surface 70 of the locking ring to provide a point of engagement by a blade 82 of the tool 80 during application of the locking ring in the manner shown in Fig. 11.

The tool 80 is then turned in a clockwise direction to uncoil the locking ring 34 until the terminal ends 34" and 34 ^b of the locking ring align and abut to lock the ring in place.

During this assembly method, the seal section 32 is compressed in a radial and bi-axial direction to provide the

triple sealing function discussed above. The sleeve portion 36 of the boot is then pulled through to the position shown in Fig. 2 by applying the clamp 66. Flexible pipe can then be inserted through the sleeve of the boot and secured to a T- fitting or other fitting in the piping system internally of the sump. The clamp 66 is then tightened to secure the sleeve of the boot assembly to the pipe. This completes the assembly.

The boot assembly of the present of invention can be easily disassembled when desired or needed. To disassemble, simply release the clamp 66 securing the sleeve section of the boot to the pipe, and then withdraw the pipe. The sleeve portion of the boot is then inverted to the position shown in Fig. 10. The tool 80 is then positioned interiorly of the locking ring so that one of the blades 82 engages the radially inwardly projecting rib 86 at one end of the locking ring. The tool 80 is turned slightly in a clockwise direction to disengage the confronting axial ends 34 ^a and 34 ^b of the locking ring. The lug end 86 of the locking ring is then displaced radially inwardly, whereby, upon release of the tool the locking ring will recoil to the position shown in Fig. 8 and permit removal of the locking ring and thereafter easy removal of the boot from the sump.

Recapping now the features of the present invention, it can be readily seen that the entry boot is easy and quick to

install and provides the triple sealing action insuring a liquid tight seal preventing migration of any liquids in the region where the pipe enters the sump. The triple seal comprises the axial compression of the sealing ring of the boot against the wall of the sump surrounding the opening from opposite directions and a radial force about it entire circumference pressing the same against the opening 28 and the sump wall. Further, as can readily be seen, the only portions of the boot assembly exposed to the ambient environment are all rubber and accordingly there are no elements or components of the boot which are likely to deteriorate by contamination or become contaminated.

Even though a particular embodiment of the invention has been illustrated and described herein, it is not intended to limit the invention. Additionally, changes and modifications have been made within the scope of the following claims. For example, other means for storing and imparting the energy for achieving the three way sealing of the boot are within the scope of the invention. Further, the tool for applying the locking ring may be in the form of a cam actuator which has a progressive characteristic allowing a single tool to be used for various sized boots.