Note : Les descriptions sont présentées dans la langue officielle dans laquelle elles ont été soumises.
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The present invention relates to a sealing ring for sealing a space between
two substantially coaxial sealing surfaces which are insertable one in the
other, especially a sealing ring for sealing the annular space between a
socket and a spigot of a pipe joint.
Many different types of sealing rings for sealing the annular space between a
socket and a spigot of a pipe joint are previously known. The prior art sealing
rings are of two main types, rolling rings and sliding rings. When providing a
pipe joint by means of these types of sealing rings the sealing ring is
positioned on one of the sealing surfaces and the sealing ring is compressed
between this sealing surface and the other sealing surface while the sealing
surfaces are axially inserted one in the other. The compression of the sealing
ring thereby obtained provides for the tightness of the pipe joint.
The present invention relates to a sealing ring of the sliding type. When using
this type of sealing ring the engagement of the sealing ring with the other
sealing surface during the axial displacement of the sealing surfaces in
relation to each other takes place either while the other sealing surface is
sliding in relation to the sealing ring, so called outer sliding, or while
there is a substantially stationary engagement between the other sealing surfaceand a portion of the sealing ring, a sliding taking place between two sliding
surfaces inside the sealing ring, so called inner sliding. In order to provide
a sliding without too great frictional resistance it is required that the
surfaces along which the sliding takes place are provided with a lubricant.
In connection with sealing rings acting with outer sliding it is a drawback thatthe lubricant has to be applied to at least one of the surfaces which shall
slide along each other at the site where the pipes shall be Jointed which is
a dirty and in connection with large pipes of the well ring type also is a
risky work. In connection with sealing rings acting with inner sliding, the
sliding takes place only inside the sealing ring. In a sealing ring of the innersliding type according to the Swedish patent No 7800282-1 the sliding surfaces
of the sealing ring are protected from dirt in such a way that it is possible
to deliver the sealing rings to the working site where the rings are to be
used with completely protected sliding surfaces provided with lubricant. Thus,
sliding rings of this type comprise two portions connected with each other
which during the insertion of the sealing surfaces one in the other substan-
tially undisplaceably engage one sealing surface each and slide against each
other along inner sliding surfaces. The two portions of the sealing ring may
be connected with each other at different places of the ring. Thus, the
portions may be connected with each other at one or the other side of ~he
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sealing ring or can be connected with each other at both
sides thereof. In the case that the portions of the sealing
ring are connected with each other at both sides of the
sealing ring or at the side of the sealing ring which after
the positioning of the sealing ring on one of the sealing
surfaces is positioned at the front side of the sealing ring
with regard to the direction of displacement of the other
sealing surface when the sealing surfaces are being inserted
one in the other there is a restriction of the length of the
axial movement of the sealing surfaces which can be conducted
after the other sealing surface has initiated its engagement
with the sealing ring. Thus, the other sealing portion of
the sealing ring, i.e. the sealing portion which is engaged
by the other sealing surface during the axial movement of the
sealing surfaces, can be displaced only so far that the place
of conn~ction between the portions of the sealing ring
remains uneffected. When conducting a jointing movement
which is longer that the distance which can be adopted by the
other sealing portion of the sealing ring, i.e. a movement
which causes an influence on the connection place between the
portions of the sealing ring, the other sealing portion will
bring with it the first sealing portion from its correct
position on the first sealing surface. This provides for an
incorrect position of the sealing ring in the pipe joint in
turn providing that it is not possible to complete the
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jointing of the sealing surfaces, that the joint will be
leaky and/or that the pipe socket is broken. In order to
make sure that the function of a sealing ring of this kind is
correct it is therefore n~cess~ry to manufacture the sealing
ring with a ~eco~ sealing portion of such a great length
that it does not bring the first sealing portion with it even
if the other sealing surface, as may occur in an excentric
assembling of the pipe, contacts the other sealins portion at
a very early stage at any place of the periphery of the
sealing ring. The increased size of the other sealing
portion for making sure that the correct function of the
sealing ring is maintA~ne~ brings about increased material
costs and is therefore inadvantageous especially with regard
to the fact that it is on every occasion only at a small
portion of the length of the sealing ring that the great
length of the other sealing portion is nececcAry.
In the present invention the first and the second sealing
portions are at least at the front side of the sealing ring
in respect of the direction of movement of the second sealing
surface during the insertion of the sealing
2a
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surfaces one in the other connected with each other by means of a releasable
and/or in a substantial degree extensible connector portion.
Thus, in the sealing ring according to the invention said connector portion
provides that the second sealing portion will not displace the first sealing
portion which is positioned on the first sealing surface from the correct
position thereof even if the second sealing portion has insufficient length
for satisfying the necessary sliding distance at any place of the periphery
of the ring.
In a preferred embodiment of the sealing ring according to the invention the
connector portion is constituted by an edge portion unitary with the second
sealing portion, said edge portion being by means of a releasable adhesive
joint connected with the first sealing portion. Thereby, the first sealing
portion may be provided with a projecting flap which is provided with
ridges and with which the connector portion of the second sealing portion
is releasably connected.
Optionally the two portions of the sealing ring may be connected with each
other or lack such connection at the side of the sealing ring opposite from
the releasable connector portion.
In a modified embodiment of the sealing ring according to the invention
the releasable connector portion is constituted by an indication of fracture in
the connection between the first and the second sealing portions. It is
possible to comply with the object of the invention also by means of a
connector portion which is thin and extensible in such a way that it is
easily extended to substantially increased length without subjecting the
first sealing portion to such forces that have any influence thereon or
prevent the jointing movement.
In an embodiment of the sealing ring in which the portions of the ring are
connected with each other at both sides of the sealing ring and there is in
the sealing ring defined a closed space the sealing ring according to the
invention is advantageous also in the respect that the releasable joint
is broken when the jointing movement is started if air is entrapped in the
closed space so that such air can escape to the environment without
preventing or obstructing the jointing movement.
In a preferred embodiment of the invention the second sealing portion is
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constituted by a thin sliding skin and it is thereby suitable to provide
the sliding skin with material reductions in the form of grooves constituting
folding indications in the sliding skin providing for a more close connection
between the sliding surfaces of the sealing portions of the sealing ring.
The invention is described in the following with reference to the accompanying
drawings.
Fig. l is an axial section of d first embodiment of a sealing ring according
to the invention.
Fig. 2 shows the section of the sealing ring of Fig. 1 on an enlarged scale.
Fig. 3 is a section corresponding to Fig. 2 of a second embodiment of a
sealing ring according to the invention.
Figs.4a, 4b and 4c show the manufacturing of the embodiment of a sealing
ring according to the invention as shown in Fig. 3.
Fig. 5 is a section corresponding to Figs. 2 and 3 of a further modified
embodiment of the sealing ring according to the invention.
Fig. 6a is a section of a further modified embodiment of a sealing ring
according to the invention.
Fig. 6b shows a detail of the sealing ring of Fig. 6a on an enlarged scale.
Figs. 7a, 7b and 7c are sections of the wall of a spigot end and a socket
of two pipes and a sealing ring according to the invention, the figures
showing the jointing of the spigot and the socket for establishing the
pipe joint.
The sealing ring shown in axial section in Fig. 1 is constituted by a sealing
ring for sealing the space between the spigot end and the socket of two pipes,
preferably two concrete pipes. The sealing ring is intended to be compressed
between two sealing surfaces of a pipe joint in order to close and seal the
space between the sealing surfaces. The pipe joint is constituted by connecting
the two coaxial sealing surfaces with each other by axially inserting the
inner sealing surface in the outer sealing surface, the inner sealing surface
being positioned on the outer surface of the spigot end and the outer sealing
surface being positioned on the inner side of the socket, the sealing ring
being positioned on the sealing surface of the spigot end before the spigot
end is inserted in the socket. A sealing ring according to Fig. 1, the
section of which is shown on an enlarged scale in Fig. 2, consists of elastic
material and comprises a first sealing portion 2 constituting the main portion
of the sealing ring and a second sealing portion 4 constituting a relatively
thin skin. The skin 4 has a connector portion 6 unitary with the skin and
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connected with the main position 2 at the upper side of the main portion in
the figure. The main portion 2 has a conical sliding surface 8, and the skin 4
extends from the connector portion 6 upwards to a folding line and from the
folding line downwards along the conical sliding surface 8 which is completely
covered by the skin 4. The skin 4 forms at its inner surface a sliding surface
10 which is adapted to slide along the conical sliding surface 8 of the main
portion 2 when the socket and the spigot end are being jointed. In order to
facilitate the sliding movement between the sliding surfaces 8 and 10 a
lubricant is positioned in the pocket defined by the sliding surfaces.
In accordance with the invention the connector portion 6 of the skin 4 is
connected with the main portion 2 in a releasable way, i.e. in such a way that
it is possible to release the skin 4 from the main portion in the area of the
connector portion 6 by pulling the skin 4. The releasable connection of the
connector portion 6 with the main portion 2 can be provided in numerous
different ways within the scope of the invention. Thus, it is possible to
provide the connection by means of an adhesive having a strength which is
adjusted so that the adhesive connection is broken when a tensioning force is
applied to the skin 4. As an alternative the connection portion may be spotwise
connected with the main portion 2, and a further alternative is that the skin
is at the connector portion 6 releasably vulcanized to the main portion 2
without the use of an adhesive.
Fig. 3 shows a section corresponding to Fig. 2 of a modified embodiment of
the sealing ring according to the invention. As the sealing ring according
to Fig. 2 the sealing ring according to Fig. 3 comprises a main portion 2,
a skin 4 having a connector portion 6a, a conical sliding surface 8a on the
main portion 2a and a sliding surface 10a on the skin 4a. The connector
portion 6a is connected with the main portion 2a according to any of the
methods described with reference to Fig. 2.
The embodiment according to Fig. 3 differs from the embodiment according to
Fig. 2 in the respect that the skin 4a is connected with the main portion 2a
not only at the connector portion 6a but also at the opposite edge 12 of the
skin 4a.
In the embodiment of the sealing ring according to the invention shown in
Fig. 3 the skin 4a has a folding indication 14 at its upper, folded edge
portion providing that the skin forms a sharper fold at its upper edge in
turn providing for a better connection of the portions of the skin engaging
6 1 338035
each other and with the conical sliding surfacè 8a of the main portion 2a.
This close connection of the skin 4a provides that the sealing ring is more
easy to handle and reduces the risk of air inclusions in the space defined by
the sliding surfaces 8a and 10a.
Figs. 4a, b and c illustrate the manufacturing of the embodiment of a sealing
ring the section of which is shown in Fig. 3. In Fig. 4a the section of the
sealing ring is shown in the position of the sealing ring after the manufacturing
of the elastomeric material of the ring. The elastomeric material of the ring may
be manufactured by extruding the profile of the ring, cutting the extruded
profile to suitable length and glueing the ends together to form the ring or
by direct compression moulding or injection moulding the ring in annular shape.
In the manufacturing the skin 4a is formed connected with the main portion 2a
at the edge 12 and is provided with the above folding indication 14. After
that the skin is folded at the folding indication 14 and is as a whole folded
towards the main portion 2a of the sealing ring to the position shown in Fig. 4b.
A bead 16 of adhesive is applied to the connector portion 6a of the skin 4a,
and a bead 18 of lubricant is applied in the pocket between the sliding surface
8a of the main portion 2a and the sliding surface 10a of the skin 4a. Finally
the skin 4a is pressed against the main portion 2a to the position shown in
Fig. 4c, wherein the adhesive bead 16 has been flattened to form an adhesive
joint between the connector portion 6a and the opposite portion of the main
portion 2a and the lubricant bead 18 has been distributed in the space defined
by the sliding surfaces 8a and 10a. In the position shown in Fig. 4c the sealingring is ready to be used for sealing a pipe joint.
The embodiment of the sealing ring according to the invention the section of
which is shown in Fig. 5 consists like the previously described embodiments
of elastic material and comprises a main portion 20 and a relatively thin
skin 22. At its lower edge the skin 22 is manufactured unitary with the main
portion 20 and at its opposite, upper edge the skin has a connector portion 24.
The connector portion 24 is connected with a flap 26 projecting from the
upper end of the main portion 20. The flap 26 has an upper, thicker portion 28
provided with ridges and a thinner portion 40 positioned between the portion 28
and the main portion. The skin 22 is at its connector portion 24 releasably
adheared to the upper portion 28 of the flap 26, which is provided with ridges.
The ridges facilitate the releasing of the connector portion 24 from the main
portion 20 in the case that the sliding surface turns out to be of insufficient
length when the sealing surfaces are jointed by being inserted onein the other.
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The thin portion 30 of the flap 26 can be extended to the double length
while the jointing movement takes place providing for a further security
so as to obtain without problems the necessary sliding length. The thin
portion 30 is also adapted to break as a consequence of a certain elongation
so that the sealing ring can provide its sliding function substantially indepen-dent of the length of the sliding distance.
In Fig. 6a there is shown the section of a sealing ring according to the
invention which is fastened in a concrete pipe socket 32 at the inner sealing
surface 34 thereof. The sealing ring comprises a main portion 36 having a
fastening portion 37 moulded into the concrete material of the socket 32.
The sealing ring has a skin 38 unitary with the main portion 36, the skin havingat the upper connection with the main portion 36 a connector portion 40 the
design of which more clearly appears from Fig. 6b. Thus, the connector portion 40
consists of a section of the skin 38 having reduced thickness and forming an
indication of rupture at which the skin 38 is broken in the case that the
jointing movement is of such length that it can not be taken up by the skin 38
per se. In the embodiment of the sealing ring according to the invention shown
in Figs. 6a and 6b the skin 38 is at its inner surface which forms the sliding
surface of the skin provided with hook shaped projections adapted to prevent
or at least obstruct an axial separation of the sealing surfaces after the
jointing.
Figs. 7a, b and c illustrate the jointing operation in providing a pipe joint
by means of a sealing ring according to the invention of the type shown in Fig. 3.
In Fig. 7a there is shown a section of the wall of a spigot end 44 and a socket
46 of two well rings which shall be sealingly connected with each other by meansof a sealing ring according to the invention. The sealing ring is tensioned ontothe spigot end 44 with the main portion 2a engaging a sealing surface 48 thereof,
the main portion 2a engaging at its lower surface 48 a shoulder 50 provided on
the spigot end. The joint is established by lowering the well ring provided withthe socket 46 downwards upon the spigot end 44 to a position in which the
sealing ring is compressed between the sealing surface 48 of the spigot end and
a sealing surface 52 of the socket 46.
~hen the upper well ring is lowered the corner 54 of the socket 46 meets with
the skin 4a of the sealing ring, the skin 4a being moved together with the
sealing surface 52 of the socket during the continued jointing movement while
a sliding movement takes place inside the sealing ring as a sliding between
the sliding surface 10a of the skin 4a and the sliding surface 8a of the
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main portion 2a. Thus, the main portion 2a is during the jointing movement
substantially indisplaceably fixed in relation to the sealing surface 48
of the spigot end 44 and the skin 4a is substantially indisplaceably fixed
in relation to to the sealing surface 52 of the socket 46.
At the stage of the jointing operation shown in Fig. 7b the excess material
of the skin 4a, that is the portion of the skin positioned above the connector
portion 6a of the skin, has so to say been consumed. In a sealing ring of the
previously known type in which the skin 4a is at the upper side of the sealing
ring firmly connected with the main portion 2a, a continued jointing movement
past the position shown in Fig. 7b would have an influence on the upper portion
of the main portion 2a providing an incorrect positioning of the sealing ring
in the pipe joint in turn causing that the jointing operation cannot be
completed and/or that the joint will be leaky.
As appears from Fig. 7c the connector portion 6a of the sealing ring according
to the invention makes it possible to complete the jointing operation without
affecting the position of the sealing ring in the joint in such a way that the
tightness of the joint is jeopardized. As appears from Fig. 7c the connector L~
portion has at this stage been released from the main portion 2a and has
uncovered the upper portion of the conical sliding surface 8a of the main
portion 2a.
It is realized that the jointing operation shown in Figs. 7a, b and c illustratean ideal coaxial position between the spigot end 44 and the socket 46 and
that a perfect coaxial position does in practice not appear during the
jointing operation. In practice the socket 46 takes a more or less excentric
position in relation to the spigot end 44 when the jointing operation is
initiated which means that the corner 54 of the socket 46 will engage the
skin 4a of the sealing ring at different points in the radial direction. This
means that the necessary length of the skin 4a may be either greater or less
than in the ideal case. This emphasizes even more the importance of the invention,
as a sealing ring of the type operating with inner sliding in absence of the
releasable connector portion according to the invention must have a great excesslength of the skin in order to make sure that the length of the skin 4a is
sufficient around the whole periphery of the sealing ring when the pipe joint
is being mounted.
The releasable connection of the skin 4a by means of the connector portion 6a
also allows that air enclosed in the space defined by the sliding surfaces
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8a and lOa can escape to the environment as a consequence of the broken
connection when the pressure in the space is increased as a consequence
of the jointing of the sealing surfaces 48 and 52. Enc10sed air might prevent
the jointing of the sealing surfaces if it does not have the possibility of
escaping from the space in question.
~he invention can be modified within the scope of the following claims.
