Note: Descriptions are shown in the official language in which they were submitted.
2113334
~WO 9S/09998 PCTIUS91/11217
FT~YTRT~T' ENTRY BOOT ASSEMBLY
nNlC~L FIEI.D
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 '3flexible entry boot assemblies" used in these
systems to connect the flexible underground piping systems to
pumping apparatus housed in underground sumps or the like.
W095/09998 2 1 73334 PCT~S9~/11217 ~
R~ 0UND 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
lS 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
~ W095/09998 2 ~ 7~3~ PCT~S94/11217
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
21 73334
W095l09998 PCT~S9~/11217 ~
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
~ W095/09998 2 ~ 7 3 ~ 3 4 PCT~S94/11217
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
wog5~cs~x 2 1 7 3 3 3 ~ PCT~S94/11217 ~
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
W095/09998 PCT~S9~/11217
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.
~ t ~ 4
WO 9S/09998 PCT/US9~/11217
DISCLOSURE OF THE 1NV~ ION
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.
~W095/09998 2 1 7 ~ 3 ~ ~ PCT~S9~/11217
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;
W095109998 2 ~ 4 PCT~S9~/11217 ~
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.
~ WO9SI~3~8 2 ~ 73334 PCT~S94/11217
BEST MODE FOR CARRYING OUT THE lNv~:NlION
Referring now to the drawings and particular to Fig. l
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
WOss/09998 2 1 7 ~ ~ 3 ~ PCT~Ss~/11217 ~
section 36 having predetermined diameter Ds slight greater than
the diameter Dp 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 400 of the seal
ring 40 to define a pocket 46 embracing the inner and outer
walls 24i and 240 of the sump base surrounding the pipe opening
28. The diameter Ds of sleeve section is smaller than the
diameter Do 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 44i and 440 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 440 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
12
~ W095/09998 2 1 7 3 3 3 4 PCT~S94/11217
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 70a 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
W09s/09998 2 ~ 7 ~ PCT~S9~tll217 ~
the locking ring in the manner described below. More
specifically, the widthwise dimension W2 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 Dm of the locking ring when it is in the fully
assembled position is slightly greater than the diameter Ds f
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 Wb of the base
of the locking ring is preferably slightly smaller than the
width Wbs of the boot and the distance W2 between the flanges
72 and 74 of the locking ring at their outer terminal ends is
preferably smaller than the cross-sectional dimension W3 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
14
W095/09998 ~1 7~ PCT~S94/11217
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 34b
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
wo95/o99s8 2 1 7 3 3 3 4 PCT~S94/11217 ~
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 thesump. 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 34a and 34b 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 ~ig. 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
2 ~
wo95los998 PCT~S94/11217
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 cont~m;n~ted.
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.
ft~ A ~
