WO1998015768A1

WO1998015768A1 - Entry fitting for sealing against container wall of variable thickness

Info

Publication number: WO1998015768A1
Application number: PCT/US1997/015749
Authority: WO
Inventors: Frank G. Lamping; James E. Kesterman
Original assignee: Dover Corporation
Priority date: 1996-10-08
Filing date: 1997-10-08
Publication date: 1998-04-16
Also published as: TW411326B; AR008314A1; AU4800397A

Abstract

An entry fitting comprises a fitting body (32) adapted for placement in an opening of a container (26) for sealingly interfacing between the container (26) and a pipe (24) extending through the container (26), and a flexible seal (40) securably attached to the body (32), the seal (40) having a recess (60) adapted to sealingly receive the wall of the container (26). The recess (60) comprises a cylindrical bottom surface (62) circumferentially disposed about the body; and first and second sidewalls (64, 66) extending radially outwardly from the cylindrical body. The first and second sidewalls (64, 66) are axially spaced by a predetermined distance and are adapted to sealingly engage the inner and outer surface of a container wall (26). At least one of the sidewalls is flexibly movable relatively to the cylindrical bottom, and has a bead extending axially into the recess for engagement with the container wall.

Description

ENTRY FITTING FOR SEALING AGAINST CONTAINER WALL OF VARIABLE THICKNESS

TECHNICAL FIELD

The present invention relates generally to the field of bulkhead or entry fittings used in underground sumps and other containers, and more particularly to an entry fitting having a seal that accommodates container walls of variable or imprecisely controlled thickness. The invention will be specifically disclosed in connection with an entry fitting

that includes a seal having a recess of a predetermined thickness for receiving and sealingly engaging container walls of thicknesses that are smaller and larger than the recess thickness .

BACKGROUND OF THE INVENTION

Entry fittings are used commonly 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 primary disadvantage of sumps or other containers formed through rotationally molding process is the imprecision

of wall thickness and the irregularity of the wall surfaces. When using seals that

sealingly engage the container wall on both the outer and inner sides, variations in wall

thickness can result in loss of a sealing engagement. For this reason, it is common to use

seals that are compressingly engaged against only one side of the container wall.

However, improved sealing of the access openings in sumps and other containers can be achieved by sealing on both internal and external container surfaces. Accordingly, there

is a need for entry fitting seals in entry fittings that seal container walls both internally and externally about access openings and that accommodate container walls of variable thickness without loss of sealing engagement.

SUMMARY OF THE INVENTION

It is thus an object of the present invention to provide a entry fitting having a seal

that effectively maintains a sealing relationship with container walls of variable

thickness.

It is another object of the present invention to provide an entry fitting sealing system in which a sealing relationship is maintained between a wall and an entry fitting when the surface of the container wall is irregular. Another object of the invention is to provide an entry fitting having a seal that effectively seals both internal and external surfaces of a container wall about an access

opening for container walls of variable thickness.

These and other objects of this invention are achieved with an entry fitting that

includes a fitting body adapted for placement in an opening of a container for sealingly

interfacing between the container and a pipe extending through the container. A flexible

seal having a recess that is adapted to sealingly receive the wall of the container is

securably attached to the body. The recess is partially defined by a cylindrical bottom surface that is circumferentially disposed about the body. First and second sidewalls extending radially outwardly from the cylindrical body further define the recess. The

first and second sidewalls are axially spaced by a predetermined distance and are adapted to sealingly engage both inner and outer surfaces of a container wall respectively. At least one of the sidewalls is flexibly movable relative to the cylindrical bottom. This flexible sidewall has a bead extending axially into the recess for engagement with the

container wall and is operative to sealingly engage container sidewalls of widths greater than and less than the predetermined width between the recess sidewalls.

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 will be regarded as illustrative in nature and not as restrictive. BRIEF DESCRD7TION 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 principals of the invention. In the drawings:

Fig. 1 is a schematic view of a fuel dispensing system using a plurality of entry

fittings that are constructed according to the principles of the present invention;

Fig. 2 is an enlarged elevational view of one of the entry fittings illustrated in Fig.

i;

Fig. 3 is a cross-sectional view of the entry fitting illustrated in Figs. 1 and 2 taken across the cutting plane 3-3 in Fig. 2; and

Fig. 4 is a diagrammatic illustration of the seal shown in Fig. 3 depicting, in exaggerated form, one of the sidewalls being deflected outwardly by a container wall having a thickness greater than the seal recess opening.

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 storage tank 26. Upon demand, fuel flows from underground fuel tank 26 through fuel conduit 24 to fuel dispensers 20 and 22. A sump, such as sumps 28 and 30 in the illustration, are positioned beneath each of the fuel dispensers to capture any fuel which may leak from the dispensers or from fittings, such as fittings 29 in sump 28. Fuel conduit 24 extends

through access openings in the sidewalls of the sump 28, and entry fittings, such as illustrated entry fitting 32 are used to seal the access opening, preventing the flow of gasoline out of the sump or the flow of groundwater into the sump. Although entry

fitting 32 is shown being used with fuel conduit 24, entry fitting 32 can also be used to seal other conduits, such as an electrical conduit.

An entry fitting 32 is positioned at each access opening in the wall of sump 28.

Entry fitting 32 provides a seal between conduit 24 and sump 28. A similar entry fitting 32 is provided in sump 30 and access 31 to seal respective access openings.

Figs. 2 and 3 show the entry fitting 32 in substantially greater detail. As is most readily apparent from a joint viewing of these two drawing figures, the illustrated entry fitting 32 includes a body 34 having a generally two generally cylindrical surfaces, a base

surface 36 and a boot sealing surface 38 (see Fig. 3). A wall seal 40 is circumferentially disposed about the base surface 36. The seal 40 is secured to the body 34 through the

agency of an axially extending flange 42 that is fitted into a correspondingly shaped groove 44 on the body 34.

The inboard portion of the base surface 36 is threaded and receives an axially advancable nut 46, which nut 46 is operative to apply an axially compressive force

against the seal 40. A washer 48 is interposed between the seal 40 and the nut 46.

The boot sealing surface 38, which is located at the inboard end of the body 34,

is adapted to receive a sealing boot 50. The boot 50 is sealingly secured to the boot sealing by a clamp 52 (see Fig. 2). Turning now to the details of the seal 40, Fig. 3 shows that the seal 40 includes

a "U" shaped recess 60 for receiving the container wall. The recess is partially defined by a cylindrical bottom surface 62 that is circumferentially disposed about the base

surface 36 of the body 34. A pair of axially spaced, radially extending sidewalls 64,66 are joined to the cylindrical bottom surface 62 and further define the recess 60.

The sidewalls 64, 66 are spaced by a predetermined distance, and are designed to

accommodate container wall thickness of approximately the same distance.

Unfortunately, it sometimes is desirable to manufacture the container walls by processes that produces imprecise wall thicknesses, as for example the sumps of the illustrated embodiment which preferentially rotationally molded.

According to one aspect of the present invention, the sidewall 66 of seal 40

includes a bead 70 that extends axially into the recess 60. Advantageously, this bead 70

assists in allowing the seal 40 to conform to container wall thickness that varies from the optional design thickness. More particularly, a container wall having a thickness slightly less than the axial spacing of sidewalls 64 and 66 will, due to the axial extension of the

bead 70, be more readily seal by the bead 70 than by the remaining portions of the

sidewall 66.

Fig. 4 schematically shows the seal 40 conforming to a container wall thickness

greater than the axial spacing of sidewalls 64,66. In Fig. 4, the sidewall 66 is illustrated as being hingedly deflected by a container wall. In this instance, the axially extending bead 70 continues sealing contact with the wall despite the deflection of sidewall 66. It

also will be appreciated that the nut 48 will apply a compressive force against the seal 40 through the washer 48. The use of the bead 70 will tend to localize these forces in a relatively small area, increasing the per unit sealing force. As a consequence, the sealing pressure against the wall is enhanced. Further, such enhanced sealing pressure increases the tendency of the seal to conform to surface irregularities of the container wall.

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. 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 entry fitting, comprising:

(a) a fitting body adapted for placement in an opening of a container for sealingly interfacing between the container and a pipe extending through the container;

(b) a flexible seal securably attached to the body, the seal having a recess

adapted to sealingly receive the wall of the container, the recess comprising:

(i) a cylindrical bottom surface circumferentially disposed about the body; and

(ii) first and second sidewalls extending radially outwardly

from the cylindrical body, the first and second sidewalls being axially spaced by a predetermined distance and

being adapted to sealingly engage inner and outer surfaces of a container wall respectively, at least one of the

sidewalls being flexibly movable relatively to the cylindrical bottom, the at least one of the sidewalls having a bead extending axially into the recess for engagement with the container wall, the flexible sidewall with the bead being operative to sealingly engage

container sidewalls of widths greater than and less than

the predetermined width between the recess sidewalls.

2. An entry fitting as recited in claim 1 further including means for compressingly urging the flexible sidewall into sealing relationship with a container wall disposed

within the recess.

3. An entry fitting as recited in claim 2 wherein the urging means includes a nut that

is axially advancable on the body.