Note: Descriptions are shown in the official language in which they were submitted.
~69~37
PIPE SEAL
I Field of the Invention
i
The present invention relates to gaskets ~or seallng
the annular gaps between pipes and structures into which the
I pipes extend. More particularly, the present invention
I relates to gaskets for use in sealing connections between
i sewer pipes and underground structures such as manholes.
I Bac~round of the Invention
In sewar lines it is customary for manholes to be
I installed at various intervals such as where the sewer line
L0 I changes elevation or direction. Conventional manholes are
fabricated of cast concrete and are provided with one or more
pipe-receiving ports which receive the ends of sewer pipes.
In order to prevent ground water from infiltrating the manhole,
1, and to prevent sewage in the manhole ~ro~ leaking outwardly
I to pollute the ground water, seals or gaskets are normally
¦ used to seal the gap between the outer periphery of the pipe
and the inner periphery of the port in the manhole.
Various types of ~eals have been proposed for this
! purpose. One such seal is disclosed in U. S. Pat. No. 3,759,280.
I This seal has a base fastened to, or embedded within, the
¦ concrete of the manhole around the pipe receiving port and a
neck which extends outwardly from the manhole along the outside
of the pipe and which is fastened to the outer periphery of the
pipe by a clamp.
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Another pipe to manhole seal is disclosed in U. S.
I, Pat. No. 3,813,107 and its companion U. S. Pat. No. 3,832,438,
~ This seal has a generally triangular cross-section with a
¦I hollow pipe-engaging portion and a pair of outturned
5 ¦¦ flanges whlch are molded into the concrete during pouring of
the manhole.
j Another pipe to manhole seal is disclosed in U. S.
Pat. ~o. 3,874,063. Thls seal assembly has a portion molded
. into the concrete manhole and a lateral annular recess
l adapted to receive an annular wedge. The wedge is driven
j into the recess after the pipe has been installed to provide
l a fluid-tight connection.
U. S. Pat. No. 4,159,829, and its companion U.S.
Pat. No. 4,073,048, each disclose another type oE gasket
Ij for a sewer pipe to m~nhole connection. This patented gasket
! has a hollow pipe-engaging portion and a T~shaped base whi~h
is molded into the concrete while the manhole is being poured.
i U. S. Pat. No. 4,103,901 discloses a pipe to manhole
seal having a base portion molded into the concrete of the
20 1l manhole and a pipe-engaging portion adapted to be secured
¦ around the pipe by a pipe clamp.
I U. S. Pat. No. 2,257,119 discloses several different
il embodiments of a seal for a cylindrical member such as a
Ii shaft.
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While each of the above disclosed patented devices
may function satisfactorily for its intended purpose, none
has all of the attributes of a commercially desirable seal.
For instance, such a seal should provide leak resistance up
-to 10 psi. and should enable the pipe to be de1ected omni-
directionally up to 20 with respect to its receiving port.
A satisfactory pipe seal should also prevent the pipe from
contacting the bottom of the pipe-receiving po~t in response
to transverse shear loads on the pipe as may be imposed by
backfill and traffic loads adjacent the manhole. The seal.
should also be sufficiently compressible as to accommodate
variations in the outside diameters of pipes of different
materials which have the same nominal inside diameters. The
seal should also be mounted securely in place and should be
capable of in-field adjustments and repair to accommodate
unusual situations. A desirable seal must also be sufficiently
foolproof as to be capable of being installed by relatively
unskilled labor, and the seal must be capable o~ beiny in-
stalled rapidly and in a minimum amount of time.
Objects of the Invention
With the foreyoing in mind, the present invention seeks
to provide a novel seal which provides all of the aforesaid
desirable characteristics in sealing the annular space between
a pipe and its receiving structure.
The present invention further seeks to provide a seal
assembly which is particularly sulted for sealin~ pipe to man-
hole joints while permitting the pipe to be dispo~ed at omni-
directional angles of up to 20 with respect to the center
line of the pipe-receiving port.
Still further, the present invention seeks to provide
a manhole to pipe seal which insures the interposition of
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resilient material between the bottom of the pipe and its
receiving port to prevent pipe damage in the event that ex-
cessive shear loads on the pipe cause it to bot~om-out in
the port.
s The pipe seal of this invention accommodates variations
in the outside diameters of pipes of different materials
having norninal inside diameters and can be field-adjusted to
accommodate unusual installation situations.
The present invention also seeks to provide a manhole
to pipe seal which resists transmission of fluids through
the concrete around the outer periphery of the seal as well
as along the pipe with which it is used and provide a seal
assemhly which is capable of being installed properly and
rapidly by relatively unskilled labor.
Summary of the Invention
More specifically, the present invention provides an
improved seal which is particularly suited for use in sealing
the annular space between the inner periphery of a port in a
manhole and a sewer pipe received therein.
In one broad aspect, the inventian comprehends a
resilient gasket for sealing an annular space between a pipe
and a surrounding aperture in a pipe receiving structure. The
gasket includes an annular ring adapted to engage the outer
periphery of the pipe, a flexible neck integral with the ring
and extending outwardly therefrom, and a base surrounding
the neck integral therewith. The base has a portion adapted
to be embedded within the pipe receiving structure and a
portion adapted to be exposed to the pipe when the gasket is
in operative association with the pipe and the pipe receiving
structure, with the exposed portion extending laterally of
the neck in opposite directions beyond the ring. The flexihle
neck eooperates with the base to afford both lateral and radial
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9837
motion of the ring relative to the base and compxession of
the ring against the exposed portion of the base.
Preferably, the base extends laterally of the neck
beyond the ring to provide a cross-section having a widthwise
dimension which is greater than its radial dimension. Pre-
ferably, a pair of mounting rings are provided to mount the seal
securely and to provide a water stop. The mounting rings have
flanges received in a pair of lateral recesses in the base of
the seal and a pair of inturned mounting flanges extending out-
wardly into engagement with the surrounding concrete of themanhole. The installed seal resists fluid leakage and is
relatively easy to install properly.
The invention also comprehends a gasket assembly for
sealing an annular space between a pipe and a surrounding aper-
ture in a molded pipe receiving structure. The gasket assemblyincludes a compressible annular ring adapted to engage the
outer periphery of the pipe, a base connected to the annular
ring in a manner affording lateral movement of the ring relative
to the base, and means mounting the base into the molded pipe
receiving structure. The mounting means includes a means
providing a pair of lateral recesses in the base and a pair
of mounting rings linking the base to the structure, each of
the mounting rings having lateral flanges~engaging in the
recesses and each having mounting flanges extending outwardly
therefrom and embedded in the molded struc-ture. Thus, the
gasket is firmly mounted in the pipe receiving structure.
1 1 69 ~ 3 7
II Brief Descripti~z~l2~Eh~Ec~2~x~
~¦ The oregoing and other objects, feature~ and
1¦ advantages of the present invention should become apparent
Il from the following description when taken in conjunction with
5 1I Lhe accompany~ng drawings, in which:
¦i FIG. 1 i~ an elevational view of a manhole having
portions broken away and sectioned to illustrate a pipe and a
~¦ seal assembly which embodies the present invention;
~I FIG. 2 is a sectional view taken on line 2-2 of
FIG. l;
FIG. 3 is a greatly enlarged sectional view of a .
, preferred embodiment of the seal of the present invention;
I FIG. 4 is a view similar to FIG. 3 but illustrating
¦! the manner in which the seal is disposed during its casting
1 into place in the manhole;
¦ FIG. S is a fragmentary sectional view illustrating
¦ the manner in which the seal can be deformed to accommodate
variations in the angle of the pipe relative to the manhole
! port;
20 ¦ FIG. 6 is an Plevational view in xeduced scale of a
seal installation fixture, the ~iew looking rightward toward
the fixture in FIG. 4; and
FIG. 7 is an enlarged sectional view illustrating
I how one of the threaded spacers is molded into place in one
~ of the mou~iting rings of the ~alla~ion fix~ure.
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Description of Preferred Embodiment
i Referring now to the drawings, FIG. 1 illustrates an
¦ underground structure, such as a m~nhole 10, into and out
I of which extend two lengths o~ pipe 11 and 12. The pipe 11
5 I has an inner end lla which ls received within a circular
I aperture or port lOa provided in the manhole 10 adjacent to its
¦ bottom wall lOb, The pipe length 12 is similarly received
¦ by the manhole lO at a diametrically opposite or other
~ predetermined location. ~n invert or channel 13 cast in situ
~¦ in the bottom o~ the manhole 10 provides a fluid connection
between opposite ends of the pipe lengths ll and 12. With
I this structure, 1uid may flow downstream from the pipe
¦ length 11 into the manhole 10, across the invert 13, and out
¦ the pipe length 12 or vice versa.
lS I In order to preYe~nt fluid or sewage charged into the
manhole lO from leaking outwardly past the end of pipe lla,
i and/or to prevent ground water from leaking into the insicle
of the manhole lO from the annular space around the end lla
'I of the pipe 11, a seal 15 embodying the present invention is
provided. As will be discussed, the seal 15 provides a leak
resistant joint, not only when the pipe is disposed in perfect
alignment with its receiving port in the manhole 10, such as
the pipe 11, but also when the pipe is angled with respect
to its Ieceiving port such as the pipe 12.
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837
1 .
Referrin~ now to FIG. 3, the seal 15 comprises a
Il hollow annular ring 20 which surrounds the outer periphery of
¦I the pipe 11 to embrace the same tightly adjacent its end lla.
¦ 1, The ring 20 is connected to an annular base 21 by means of a
¦, narrow, flexible, continuous neck 22 which is integral with
¦~ the ring 20 and the base 21. The seal 15 is preferably
¦I fabricated of relatively soft rubber or other resilient material
ha~ing a hardness of about 50 Shore duro~eter. The seal 15 is
I extruded as a linear structure which is cut to length and formed
~l into an annular shape of any desired diameter. The ends of
I the cut length are w lcanized to provide a unitary annular
j structure and to render the ring portion 20 of the seal 15
airtight. This thereby provides the ring portion with a certain
¦I degree of mechanical softness or resiliency. By way of example,
1 for a pipe having a n~minal inside diameter oE 8 inches, the
!~ length of the extrusion before its ends are joined should be
!~ 33 inches for pipe fabricated of either polyvinyl chloride,
clay or concrete.
1 The seal 15 is designed to increase its leak resistance
¦ as hydrostatic pressure increases. To this end, the seal 15
may be shaped during installation to orm a pressure pocket 23.
For this purpose the se-al 15 is formed with the ring 20, neck
1 22 and base 21 having a cross-section which is symmetrical with
¦I respect to a radial line through the center of the ring 20.
!' The neck 22 is flexible and connects the ring 20 to the base 21
in a manner affording both lateral (lengthwise of the pip~) and
radial (outward of the pipe) movement of the ring 20 relative
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11691337
to the base 21 during installation. Thus, with the ring 20
I disposed in the manner lllustrated in ~IG. 3, i.e. offset to the
¦ left or outside of the manhole, the pressure pocket 23 is formed
¦l on the outside of the manhole as illustrated. The pressure
¦¦ pocket 23 unctions, when fluid pressure is applied in the
! rightward, or lnward direction toward the inside of the manhole,
to force the ring 20 more tightly into engagement with the outer
periphery of the pipe end lla and thereby to effect a tighter
I radial compression seal.
I The pressure pocket 23 is ormed during ins~allation
by first pushing the pipe 11 rightward into the manhole 10 and
j then pulling the pipe ll outward. The pressure pocket 23 is
li located toward the outside of the manhole in those installations
¦I where hydrostatic pressure causing ground water to leak into
15 1I the manhole is a greater problem than leakage oE sewage from
¦ the manhole. Of course, should it be desired to place the
pressure pocket 23 on the inside o the manhole in the event
j that leaka~e out of the manhole is of greater concern, this
I can be done simply by pushing the pipe 11 into the manhole so
I tha~ the ring 20 is disposed toward the right or inside of the
manhole 10, instead of toward the left as illustrated in FIG. 3.
The seal 15 prevents the pipe 11 from being damaged
in the event that excessive downward shear loads should force
j the pipe end lla downwardly and tend to cause the pipe to
I bottom-out. To this end, the seal base 21 has a pair 3f
Ij continuous interior surfaces 25 and 26 which diverge a~ a dihedra~
i¦ angle of about 140 relative to one another and extend outwardly
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and radially wi~h respec~ to the seal ring 20. The surfaces
~5 and 26 extend laterally o~ the neck ?2 beyond the outer
; extremity of the rlng 20 so that the ring 20 can be compressed
,, and en~a~ed against one or the other o~ the surfaces 25 or 26,
such as in the manner illustrated in FIG. S where the pipe is
inclined and urged do~nwardly toward the bottom of the port lOa.
, This stxucture insures the interposition of a layer of
resilient material between the underside of the pipe end lla
, and the bottom o~ the port lOa in the manhole 10, thereby
1' pro~ecting the pipe end lla agains~ being broken or damaged by
, excessive shear loads. Air displaced from the bottom tends to
exert pressure elsewhere in the seal ring 20 to help assure
leak resistance.
! Preferably, the seal ring 20, the neck 22 and
' base 21 thereof are sized so ~hat the overall radial dimension
j of the seal cross-section is less than the overall lateral
! dimension thereof. This dimensioning facilitates the formation
Il of the linear extrusion into an annulus by eliminating the need
j' to twist the seal, and this in turn facilita~es proper
¦¦ installation o the seal as will be described. By way of
example, and not by way o~ limitation, it is pre~erable for
1~ the seal 15 to have a cross-section with the ring 20 having
¦1 an outside diameter o~ 1.0 inch, an inside diameter of .5 inches,
and a neck having a length o .312 inches and a thickness of
~5 Il .125 to .187 inches. The overall height or radial dimension
~, of the seal should be 2.75 inches, and the overall widthwise
or lateral dimension at the base should be 3.0 inches.
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Il
The seal lS is firmly mounted in place in the manhole
in a manner which resists loosening and which resists the
' transmission o~ water around its outer periphery. To this end,
Il opposite sides o the base 21 of the seal 15 are provided with
5 ~ a pair of lateral rece4seS or gxooves 27 and 28 and a pair of
mounting rings 30 and 31 cooperate with the base 21 to mount the
seal 15 securely in the concrete of the manhole 10. As best
Il seen in FIG, 3, each ring, such as the lefthand or outer ring 30,
¦' has a flange 30a which is recei~ed within the recess 27 and ~
¦l which extends outwardly therefrom to orm a lateral dihedral ,
extension o~ the seal base surEace 25. The ring 30 also has an
¦~ inturned flange 30b which extends downwardly and laterally inward
with respect to the seal lS to terminate in spaced relation with
li respect to the corresponding flange 31b of the companion ring 31.
lS l' The rings are preferably abricated of a plastic
¦I material which, as will be discussed, forms a mechanical bond
in the concrete. The mechanical bond is effected during pouring
of the manhole 10 when concrete is 10wed into the space 32
defined within the r,ing 1anges 30b and 31b and into a peripheral
~ 20 I groove 29 formed about the outer periphery of the seal lS.
: ¦ Concrete surrounding the mounting ~lange5 30b and 31b causes the
flanges, and the seal 15, to be irm1y embedded within ~he
s~ructure of the manhole 10. This arrangement provides ~he
, advantage, not only o~ preventing water from seeping laterally
~I through the manhole wall across the outer periphery of the seal
15, but also of firmly mounting the seal 15 in the manhole port
lOa. ~hile such mounting is intended to be permanent, the seal
15 could, with some difficulty, be cut out from the mounting rings I
and another seal installed with the mounting ring flanges
engaged in its side recesses 27 and 28.
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While it is, of course, most preferable for the
~' mounting rings 30 and 31 to be utilized, they may be omitted
where the full advanta~es realized by their use may not be
, required in the particular application. In such event, the
ll seal 15 is positioned so that concrete is flowed into its
side recesses 27 and 28 where the mounting ring flanges would
normally engage. This ensures that a soft surface confronts
the pipe to protect it ~rom damage. In order to provide a
j, peripheral water block in such event, a T-shaped protrusion
¦l is provided in the peripheral recess 29 to orm a labyrinth
¦I which prevents water from seeping across the outer periphery
Il o the seal 15.
¦I The seal lS can be installed properly and readily
Il with a minimum of skilled labor. For this purpose, an
i installation fixture 40 is provided to maintain the seal 15
ll properly disposed while the concreee of the manhole lO is being
!~ poured. Referring now to FIG. 4 the installation fixture 40
¦! comprises a pair of dished retainers 41 and 42 having
I peripheral walls shaped to engage the base 21 of the seaL 15
I and the flanges 30a and 31a of the m~unting rings 30 and 31 in
¦ the manner illustrated. The retainers 41 and 42 have circular
! transverse walls 41a and 42a which extend across the manhole
port lOa to enga~e opposite sides of the ring portion 20 of
~I the seal 15. The walls 41a and 42a thus cooperate to maintain
I the seal 15 with its neck 22 erect and extending radially
inward from the base 21 toward the center.
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In order to preven~ the ring por~ion 20 of the
seal 15 from being compreqsed between ~he walls 41a and 42a,
i a series of spacers, such as the spacers 43 and 44 in FIG. 4
~ are molded into the retainer end wall 41a of the retainer 41
I so as to abut the inside of the end wall 42a of its
companion retainer 42 in the manner illustrated. The spacer 43
is internally threaded to receive a bolt 45 which, when
I tightened, draw~ the retainer walls 41a and 42a into the proper
I spaced parallel relation illustrated in FIG. 4. Thus, the
¦I seal lS, with its mounting ring~ 30 and 31 assembled
¦` therewith, may be handled as an assembLy and mounted in the
molds used to pour the concrete o~ the manhole in accordance
with conventional technique~. Preerably, the retainers 41
', and 42 are drawn together close enough to allow the bolts to
, be started by means of a compression tool (not shown) which
¦i engages opposite sides o~ the retainer ~alls 41~ and 42a and
which has a jackscrew extending through the holes 41b and 42b
~, therein so that rota~ion of the jackscrew draws the retainers
' together.
1 20 ¦ After the manhole ha9 been poured and allowed to
set, the retainer bolts are loosened and the retainers 41
and 42 removed to leave the seal 15 pxoperly installed and ready
to receive a length of pipe. Pxeferably, the end o~ the pipe I
Il is lubricated before it is engaged with the seal 15 and, as
~I noted above, the pressure pocket 23 can be foxmed on ~he
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1 1 69 ~ 3~
¦, outside of the m~nhole simply by sliding the pipe axially into
i the m~nhole and ~hen withdrawing the Qame slightly to dispose
thP sealing ring 20 toward the outside of the manhole 10.
Il Th~s ensure~ ~hat hydrostatic p~es9ure on the out~ide of the
S I manhole 10 will force the ring 20 into even tighter engagement
l! with the pe~iphery of the pipe 11 to augment its sealin~
I contact with t~e pipQ as pres~ure lncr~a~es. In ~he event
that there sh~uld be an out-o-roundne~s of the pipe, the
I hollow rin~ portion 20 may be in1ated wi~h air under pres5ure
¦ using a needle and hand pump, or a c~mpo~it~on capable of
foaming inside th~ xing 20, ss known in the art. In the
event that excessive downward shear loads are applied to the
¦ pipe and/or the pipe is tilted with respect to the manhole
port, the seal lS deforms, such as in the manner illustrated
in FIG. S. This structure thus ensures the presence of resilient
material around ~he bottom of the pip~ and the manhole por~
i and prevent~ pipe breakage even when sub~tantial shear loads
(on the order of lS0 pound~ per inch of pipe diameter) are
I applied downwardly to the pipe 11. M~reover, the mounting
I rings 30 and 31 cooperate wlth the seal base 21 to prevent
j gasket pull-out during as~embly, thereby eliminating something
¦ which is a problem with certain commercial gaskets. This
, assembly also eliminate9 ~eathe~ edges of concrete a~ critical
j locations adjacent the seal, thereby avoiding the possibili~y
I of the concrete'~ cracking out arld allc~wing the seal ~co work
loose.
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. In view of the foregoing it should be apparent that
the present inventlon now provides an improved pipe seal which
overcomes the limitations o~ prior art pipe seals and which
I provides a number of significant advanta~es, including being
capable o being installed readily with a minimum of labor
and in a rela~ively oolproof manner and being formed into
I various diameters to accommodate a wide range of pipe sizes.
ji While a preferred embodiment of the present invention
I, has been described in detail, various modifica~ions, .
1'. alterations and changes may be made without departing from
Il the spirit and scope of the present invention as defined
: , in the appended claims.
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