WO1998015765A1

WO1998015765A1 - Entry fitting sealing system for underground sump

Info

Publication number: WO1998015765A1
Application number: PCT/US1997/018287
Authority: WO
Inventors: Frank G. Lamping
Original assignee: Dover Corp
Current assignee: Dover Corp
Priority date: 1996-10-08
Filing date: 1997-10-08
Publication date: 1998-04-16
Anticipated expiration: 1999-04-08
Also published as: AR008316A1; TW468659U; AU4814297A

Abstract

An entry fitting sealing system for an underground sump. The entry fitting includes a hub portion (56) and a flange portion (54), and a plurality of studs (46) which extend axially outwardly from the flange portion. The studs extend through apertures (58) in the sump wall (48) and through a compression ring (42) positioned in the interior of the sump. Nuts (44) engage the studs and pull the flange against the exterior of the sump wall. The exterior of the flange includes a plurality of flexible ridges (50) which provide line contact with the exterior of the sump wall and conform to the rough surface to achieve a strong seal with relatively low compressive forces.

Description

ENTRY FITTING SEALING SYSTEM FOR UNDERGROUND SUMP

TECHNICAL FIELD

The present invention relates generally to the field of bulkhead or entry fittings used in underground sumps, and will be specifically disclosed as an entry fitting sealing system for sealing against an irregular surface.

BACKGROUND OF THE INVENTION

Entry fittings are used in underground sumps to seal the interface between an

access opening of the sump and a pipe extending into the sump through the access opening. Entry fittings are designed to prevent the flow of a fluid, such as gasoline, which has leaked into the sump, from entering the surrounding ground and for preventing the flow of ground water into the sump.

An underground sump can require one or more such entry fittings depending upon

the number of fuel conduits entering and exiting the sump. In an effort to reduce the cost of underground systems, it has been found advantageous to manufacture the sumps as

economically as possible. One advantageous method of manufacturing sumps is a rotational molding process, in which powdered plastic material is inserted into a rotating

mold. While the rotational molding process is highly advantageous, it is not without disadvantages. One such disadvantage is variability in wall thickness and the formation irregularities on the surfaces. Due to these disadvantages, it often is difficult to maintain

a sealing relationship between the sump wall and the seal of an entry fitting.

A conventional entry fitting includes a rubber boot having a planar portion and a tubular portion, the tubular portion being conjoint with and perpendicular to the planar

portion. The planar portion is positioned on the exterior of the sump wall and contains

studs or bolts extending through a matching of holes in the sump wall and a compression ring positioned on the interior of the sump wall. Nuts threadedly engage the studs and

urge the planar portion against the exterior of the sump wall. The tubular portion extends

into the sump through the access opening and is sealingly clamped to the pipe. This type

of entry fitting has a sealing interface with a relatively wide planar surface and thus requires relatively high compressive forces to properly seal against a surface having

irregularities.

Accordingly, it is apparent there is a need for entry fitting sealing systems that

effectively maintain the sealing relationship between the sump wall and the entry fitting

under relatively low compression.

SUMMARY OF THE INVENTION

Accordingly, an object of the invention is to provide an improved sealing system

against a sump wall.

Another object of the present invention to provide an entry fitting sealing system that effectively maintains a sealing relationship between a sump wall having an irregular

surface. A further object of the present invention to provide an entry fitting sealing system in which a sealing relationship is maintained between a sump wall and an entry fitting

when the seal of the entry fitting is under relatively low levels of compression.

Additional objects, advantages, and novel features of the invention will be set forth in part in the description that follows and in part will become apparent to those skilled in the art upon exairiining or practicing the invention. The objects and advantages

of the invention may be realized and obtained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

These and other objects of this invention are achieved with an underground containment system that includes an underground container having at least one wall with an irregular surface. The wall defines a wall opening that is used for the passage of an

underground pipe that extends into the container. An entry fitting is provided that

includes a body having a central hub portion adapted for disposition in the wall opening.

A flange portion is circumferentially disposed about the hub portion. A plurality of

threaded studs extend axially from the flange portion in circumferentially spaced

relationship to the hub portion. A plurality of apertures extend through the wall in

circumferentially spaced relationship about the wall opening. The apertures are spaced

in correspondency to the spacing of the threaded studs, and the threaded studs are received by the apertures when the hub is disposed in the wall opening. A plurality of flexible ridges extend around the flange portion and about each of the circumferentially

spaced threaded studs. The ridges are in sealing contact with the irregular wall surface of the container for providing a plurality of independent sealing interfaces between the

wall and the body. Still other objects of the present invention will become apparent to those skilled in this art from the following description wherein there is shown and described a

preferred embodiment of this invention, simply by way of illustration, of one of the best

modes contemplated for carrying out the invention. As will be realized, the invention is capable of different obvious aspects all without departing from the invention.

Accordingly, the drawings and description are illustrative in nature and not restrictive.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings incorporated in and forming a part of the

specification, illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:

Fig. 1 is a schematic cross-sectional view of a fuel dispensing system showing an

entry fitting according to one embodiment of this invention;

Fig. 2 is an enlarged cross-sectional view of the entry fitting illustrated in Fig. 1;

Fig. 3 is an exploded view of the entry fitting of Figs. 1 and 2;

Fig. 4 is an elevational view showing the sealing face of the entry fitting of Figs.

1-3;

Fig. 5 is a cross-sectional elevational view of the body portion of the entry fitting

shown in Figs. 1-4; Fig. 6 is an enlarged view of the sealing surface illustrated in Fig. 4, showing

sealing detail around the threaded stud; and

Fig. 7 is a sectional view taken along line 7-7 in Fig. 6. Reference will now be made in detail to the present preferred embodiment of the

invention, an example of which is illustrated in the accompanying drawings, wherein like numerals indicate the same elements throughout the views.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings, Fig. 1 shows a schematic view of a fuel

dispensing system. Fuel dispensers 20 and 22 are in communication with fuel conduit 24 which in turn is in communication with underground fuel tank 26. Upon demand, fuel flows from underground fuel tank 26 through fuel conduit 24 to fuel dispensers 20 and

22. A container, such as sumps 28 and 30, surround each location where it is necessary

to provide fuel conduit 24 with a fitting. Sump 28 captures fuel which can leak from

fitting 29 or fuel dispenser 20 and prevents such fuel from entering backfill 68.

Additionally, the sump 28 prevents ground water from entering the sump 20. An entry fitting 32 is positioned at each access opening in the wall of sump 28 which fitting 32

provides a seal between conduit 24 and sump 28.

In the embodiment shown in Fig. 2 body 34 includes hub portion 56 about which flange portion 54 is circumferentially disposed. Hub portion 56 and flange portion 54 are

preferably integral. Hub portion 56 is adapted to be positioned in the opening 49 formed iri wall 48, and is adapted to receive fuel conduit 24. Clamp 52 sealingly urges hub portion 56 radially inward against fuel conduit 24.

Threaded studs 46 are formed in and extend axially outward from flange portion 54 in spaced relationship to hub portion 56. Wall 48 has a plurality of apertures 58 in a circumferentially spaced relationship about the opening 49 in wall 48. Studs 46 extend through apertures 58 and through compression ring 42. Compression ring 42 preferably

has a ring flange 43 for added rigidity and strength to the ring, which in turn facilitates better and more uniform seal compression. Nuts 44 threadedly engage studs 46 and urge

flange portion 54 against the exterior of wall 48.

Flange portion 54 includes ridges 50 which achieve an improved sealing interface between flange portion 54 and the exterior of wall 48. Sumps are frequently constructed from a rotational molding process, in which powdered plastic material is inserted into a

rotating mold. One characteristic associated with this process is the imprecision of wall

thickness and the irregularity of the surfaces. Similarly, sumps formed from other materials such as fiberglass may also experience variability in wall thickness and surface

irregularities. Additionally, sump surfaces can become damaged through rough treatment or warping from sun exposure, causing or further aggravating wall thickness variability

and surface irregularities. As a result, it often is difficult to maintain a sealing

relationship between wall 48 and flange portion 54.

Ridges 50 achieve a superior sealing interface between wall 48 and flange portion

54 by compensating for the irregularities in the exterior surface of wall 48. Furthermore, ridges 50 can achieve a seal with much less compressive force than a conventional seal. Conventional seals include a planar surface which conform well to smooth surfaces, but

have difficulty conforming to rough surfaces. To compensate for this, entry fittings

utilizing planar seals require relatively high compressive forces to eliminate leakage about the seal. Ridges 50 are sufficiently narrow to more easily conform to the rough

exterior of wall 48 and continue to provide a seal even with relatively low compressive forces. Fig. 3 is an exploded view of entry fitting 32 according to one embodiment of this

invention. Compression ring 42 has a plurality of apertures for receiving studs 46. Flange 43 adds rigidity and strength to achieve improved seal compression. Ridges 50

are preferably integral with flange portion 54 and can be made from any suitable elastomeric material. Ridges 50 achieve increased conformance properties over

conventional seals having a relatively wide planar sealing surface because they provide

a plurality of line contact points, each of which is better able to conform to the exterior of wall 48 than the surface of a conventional seal. Ridges 50 also require less

compressive force than a conventional seal because ridges 50 have a relatively small

surface area contacting the exterior of wall 48 thus providing a higher sealing pressure

for the same compressive load provided by the studs 46. As a result, ridges 50 can more readily conform to the rough exterior of wall 48 and flow into irregularities compared to

the relatively wide planar surface of conventional seals. Additionally, the embodiment of Fig. 3 includes a series of parallel ridges, which provides redundant sealing capability.

Fig. 4 is an elevational view showing the sealing face of entry fitting 32 shown

in Figs. 1-3. Ridges 50 extend around flange portion 54 and about each stud 46. Ridges

50 achieve significant line contact with wall 48. Ridges 50 also provide a circumferential sealing interface about each stud 46. Ridges 50 can comprise any suitable pattern suitable for achieving such contact.

Fig. 5 shows a cross-sectional elevational view of the body portion of entry fitting

32 shown in Figs. 1-4. _{Λ Λ C}^_C O 98/15765

Fig. 6 shows an enlarged view of ridges 50. Fig. 7 is a sectional view taken along line 7-7 of Fig. 6. As shown in Fig.7, ridges 50 are preferably integral with flange portion 54.

The foregoing description of a preferred embodiment of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. For instance, the present invention

can be used to seal a variety of other conduits, such as electrical conduits. Furthermore, a variety of other entry fitting arrangements could employ the ridged seal configuration.

Obvious modifications or variations are possible in light of the above teachings. The

embodiment was chosen and described in order to best illustrate the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to

best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention

be defined by the claims appended hereto.

Claims

WHAT IS CLAIMED IS:

1. An underground containment system, comprising:

(a) an underground container, the underground container having at least one wall with an irregular surface, the wall defining a wall opening for the passage of an underground pipe;

(b) an entry fitting, the entry fitting' including a body having a central hub portion and a flange portion circumferentially disposed about the hub portion, the central hub portion of the body being adapted for disposition in the wall opening;

(c) a plurality of threaded studs extending from the flange portion of the body, the studs extending axially outwardly from the flange portion in circumferentially spaced relationship to the hub portion;

(d) a plurality of apertures extending through the wall, the apertures being in circumferentially spaced relationship about the wall opening in correspondency to the spacing of the threaded studs, the threaded studs being received by the apertures when the hub is disposed in the wall opening; and

(e) a plurality of flexible ridges continuously extending around the flange portion and about each of the circumferentially spaced threaded studs, the ridges being in sealing contact with the irregular wall of the container for providing a plurality of independent sealing interfaces between the wall and the body.

2. An underground containment system as recited in claim 1, wherein at least one of said plurality of ridges extends continuously around the flange and is located radially inward relative to the plurality of threaded studs.

3. An underground containment system as recited in claim 1, wherein at least one of said plurality of ridges extends continuously around the flange and is located radially outward relative to the plurality of threaded studs.

4. An underground containment system as recited in claim 1, wherein at least one of said plurality of ridges intermittently extends around the flange at the radius of the plurality of threaded studs.

5. An underground containment system as recited in claim 1 , wherein the plurality of flexible ridges comprises:

(a) a first flexible ridge extending continuously around the flange, said first flexible ridge being located radially inward relative to the plurality of threaded studs;

(b) a second flexible ridge extending continuously around the flange, said second flexible ridge being located radially outward relative to the plurality of threaded studs; and

(c) a third flexible ridge intermittently extending around the flange, said third flexible ridge being located at the radius of the plurality of threaded studs.

6. An underground containment system as recited in claim 5, wherein the first, second, and third flexible ridges are interconnected by the flexible ridges located about each of the threaded studs.

7. An underground containment system as recited in claim 1 , wherein the plurality of flexible ridges are interconnected to one another.

8. An underground containment system as recited in claim 1 , wherein the plurality of flexible ridges are made from an elastomeric material.