Bulkhead fitting for underground sump

Pipe joints or couplings – Pipe to discreet nipple or sleeve to plate – Plate clamped between flanged nipple and separate fastener

Reexamination Certificate

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Details

C285S196000, C285S216000, C285S208000

Reexamination Certificate

active

06224115

ABSTRACT:

TECHNICAL FIELD
This invention relates generally to the field of bulkhead or entry fittings used in underground sumps, and more particularly to an entry fitting which achieves an increased range of adjustable sealing force.
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. Access openings are usually formed in the sump at the installation site. Due to varying conditions in the field, and of the sump itself, an access opening can sometimes be out-of-round, or have an irregular shape. Conventional entry fittings, however, have a relatively fixed or small range of sealing force, and will only properly seal when used with an access opening that has a regular shape, and also a certain diameter. Thus, if an irregular access opening is formed in a sump, or the diameter is slightly larger than specified for the particular entry fitting size, either a larger hole must be formed and a larger entry fitting utilized, or the sump must be discarded.
After an entry fitting has been initially installed, the seal eventually ages and takes a compression set. Slight movement of the pipe or thermal expansion and contraction can result in leakage about the seal. When this occurs, conventional entry fittings must be entirely replaced due to the lack of or the relatively small range of adjustable sealing force provided by such entry fittings.
There are several conventional entry fitting designs in use. One such entry fitting includes a rubber boot have 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 bolts which extend through a plurality of holes drilled in the sump and through a compression ring positioned on the interior of the sump wall. Nuts threadedly engage the bolts and pull 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 does not allow a range of adjustable sealing force between the planar portion and the sump wall, and requires considerable installation time due to the required drilling of holes, and tightening of the requisite nuts and bolts. Further, if the boot develops a leak, the entire entry fitting must be replaced, since there is not a separate seal separable from the entry fitting. Further, replacement of the entry fitting may necessitate removal of backfill from the exterior of the sump to permit withdrawal and replacement of the boot.
Another conventional entry fitting currently in use includes a boot which is positioned in the access opening, and a rigid plastic insert which is forced into the boot to be concentric with the access opening and radially urge the boot against the edge of the access opening. However, the rigid plastic insert has a predetermined size, and thus the boot and insert require a fairly specific size opening. Further, if the boot develops a leak, the entire boot must be replaced as there is no mechanism for increasing the radial force exerted by the plastic insert.
It is apparent that an entry fitting which achieves an increased range of adjustable sealing force and allows flexibility in the size and shape of access openings in which it can be used, which allows replacement of a relatively inexpensive seal without replacement of the entire entry fitting, and which can be replaced without requiring removal of backfill from the exterior of the sump would be desirable.
SUMMARY OF THE INVENTION
It is one object of this invention to provide an entry fitting which achieves a wide range of adjustable sealing force.
It is another object of this invention to provide an entry fitting which can seal a relatively large range of access opening diameters.
It is another object of this invention to provide an entry fitting which can effectively seal irregular shaped access openings, and which can later be adjusted to reseal an access opening which has begun to leak.
It is still another object of this invention to provide an entry fitting in combination with a shield which allows replacement of the entry fitting or the entry fitting seal without requiring removal of backfill from the exterior of the sump.
It is yet another object of this invention to provide an entry fitting which allows replacement of a relatively inexpensive seal rather than an entire entry fitting.
It is still another object of this invention to allow easy replacement of a seal without requiring unclamping and reclamping of an end of the entry fitting.
These and other objects of this invention are achieved with an entry fitting having a body with an exterior surface in which a first portion of the surface has a first radius, a second portion of the surface has a second radius, and the second radius is greater than the first radius. A transition portion of the exterior surface of the entry fitting is positioned between the first portion and the second portion, and the transition portion has a greater radius than the first portion and a smaller radius than the second portion. A seal is circumferentially positioned about the body, and provides a sealing interface between the body and a sump access opening. An axial displacement member such as a nut is positioned about the body and urges the seal axially along the exterior surface of the body. As the seal is axially moved against the transition portion, the seal is radially urged outward against the edge of the access opening. The exterior surface of the body which forms the transition portion has an increasing radius in a direction toward the second portion. Thus the transition portion can be adjusted with respect to the access opening to provide a seal for a relatively large range of access opening diameters. Further, the transition portion can be axially adjusted with respect to the access opening to provide an adjustable range of sealing force.
According to one embodiment of this invention, a seal is positioned about the entry fitting body and contains an annular groove which closely receives an edge of the sump wall forming the access opening. A first circumferential portion of the interior surface of the seal conforms to the contour of the transition portion, while a second circumferential portion of the interior surface of the seal conforms to the first portion of the surface.
According to another embodiment of this invention, a shield having a first end and a second end is provided which is positioned on the exterior of the sump wall. The shield defines an internal access space intermediate the first and second ends. The access space is disposed about an axial portion of the pipe and has a diametral dimension larger than the corresponding diametral dimension of the entry fitting. The access space has an axial dimension sufficient to allow displacement of a portion of the entry fitting into the access space. The first end of the shield circumscribes the access opening and is in proximity to the wall so as to inhibit the flow of backfill material into the access space between the shield and the wall. The second end of the shield circumscribes the pipe so as to inhibit the flow of backfill into the access space between the shield and the pipe. The shield is removably fixed with respect to the pipe so as to selectively prevent relative axial displacement between the pipe and the shield and to secure the position of the shield relative to the wall.
Still other objects of the present invention will become apparent to those skilled in this art from the following description wherein t

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