Pipe part having a socket provided with a sealing assembly, and sealing assembly

Abstract: In a pipe part having at least one socket (1), into which a spigot (3) of another pipe part can be inserted, the socket (1) is provided on the inside with a separate, annular sealing assembly (2) comprising a sealing ring (4) made of an elastomeric material and a retaining ring (5) made of a rigid material which is firmly connected thereto. The sealing assembly (2) is provided on the outside with an annular rib (6), which projects outwards, is made of resilient material and slots into a groove (7) arranged on the inside of the socket (1). At least a portion of the annular rib (6) is arranged on the outside of the retaining ring (5). As a result, very accurate positioning of the sealing assembly (2) in the axial direction is achieved with respect to the socket.

Description: The invention relates to a pipe part according to the preamble of claim 1. A pipe part of this type is known from GB-A-457,629. In this known pipe part, the annular rib forms a part of the sealing portion of the sealing ring and is arranged near the free end of the sealing ring, where the sealing ring has a substantially round cross-section. The disadvantage of the known pipe part is that, due to the fact that the annular rib is the main sealing portion of the sealing ring which has to be deformed in order to perform its sealing function, the correct positioning of the sealing element with respect to the socket cannot be guaranteed. The object of the invention is to provide a pipe part in which this disadvantage does not occur. This object is achieved according to the invention in a pipe part with the characteristic features of claim 1. A very good fixation and a very accurate positioning of the sealing assembly in the axial direction with respect to the socket is achieved by means of this annular rib. Even in the event of axial movements of the spigot in the socket, the sealing assembly will remain in place. Due to the deformability of the material of the rib, accurate positioning is still achieved even in the event of relatively large tolerances of the internal diameter. This means that the sealing element is also well suited for use in sockets which are moulded to pipes and in sockets which are produced by injection-moulding, in which case the internal groove is formed without using folding cores. Preferred embodiments of the pipe part according to the invention are defined in the dependent claims. The invention likewise relates to a sealing assembly according to claim 6 which is suitable for use in a pipe part with a socket according to the invention. US-A-4,834,398 discloses a sealing assembly comprising a sealing ring made of an elastomeric material and having a sealing portion, and a retaining ring made of rigid material which is firmly connected to the sealing ring and which extends in axial direction away from the sealing ring, the sealing assembly being provided on the radial outside with an annular rib which projects radially outwards and is made of resilient material, at least a portion of the annular rib being arranged on the radial outside of the retaining ring. In this sealing assembly the sealing portion of the sealing ring is arranged radially inside the annular rib. The invention will be explained in the following exemplary embodiment with reference to the drawing, in which: Fig. 1 shows an axial cross-section through part of a socket of a pipe part according to the invention; Fig. 2 is an axial cross-section through a first embodiment of a sealing assembly which can be used in the pipe part according to the invention; Fig. 3 is a partial axial cross-section through a second embodiment (top) and a third embodiment (bottom) of a sealing assembly which can be used in the pipe part according to the invention. In Fig. 1, part of a socket 1 of a pipe part according to the invention is depicted. The socket 1 is provided on the inside with a separate sealing assembly 2. A spigot 3 of another pipe part can be inserted into the socket 1, in order to form a connection between these two pipe parts. In particular, the pipe parts are produced from a plastic, such as polyvinyl chloride (PVC) or polypropylene (PP), but the invention is not limited to these materials. The sealing assembly 2, which is depicted in its entirety in Fig. 2, comprises a sealing ring 4 made of an elastomeric material and a rigid retaining ring 5, which is firmly connected to the sealing ring 4 and is made of a rigid material. The sealing ring 4 is intended to provide the sealing between the socket 1 and the spigot 3 when the spigot 3 is inserted into the socket 1. The retaining ring 5 is preferably produced from a rigid plastic, for example polypropylene. The sealing assembly 2 is preferably produced by co-injection, the sealing ring 4 and the retaining ring 5 being firmly connected to one another during the moulding process. In this case, the sealing ring 4 preferably consists of a thermoplastic elastomer which adheres well to the material of the retaining ring 5. It is, however, also possible to connect the sealing ring 4 and the retaining ring 5 to one another in a different manner. The sealing assembly 2 is provided on the outside with an annular rib 6 which projects radially outwards. At least a portion of the rib 6 is arranged on the outside of the retaining ring 5. This rib 6 fits into a groove 7 arranged on the inside of the socket 4. In this way, the sealing assembly is very accurately positioned in the axial direction with respect to the socket 1. Axial movements by the spigot 3 inserted into the socket 1 have no effect on the position of the sealing assembly 2 with respect to the socket 1. The rib 6 preferably forms part of the sealing ring 4 and is, in this case, arranged in the region of the connection between the sealing ring and the retaining ring 5. At the end connected to the sealing ring 4, the retaining ring 5 is preferably provided with a tapered portion. In this way a very good connection to the sealing ring 4 is achieved. In Fig. 3, two embodiments of a sealing assembly are depicted which have been modified slightly with respect to the embodiment of Fig. 2. In the top part of the figure, an embodiment of a sealing assembly 2' is depicted in which the retaining ring 5' is provided on the side remote from the sealing ring 4 with a radially outwardly projecting flange 8. The flange 8 bears against the front end 9 of the socket 1 or is at a small distance therefrom when the sealing assembly 2' is arranged in the socket 1 (see Fig. 1). The flange 8 serves to mask the gap 10 between the retaining ring 5' and the socket 1. The flange 8 is not necessary for positioning the sealing element 2' in the socket 1. In the bottom part of Fig. 3, an embodiment of a sealing assembly 2'' is depicted, in which the retaining ring 5 is provided, at least in the vicinity of the connection to the sealing ring 4, with a thin layer 11 which consists of the same material as the sealing ring 4. As a result, a better connection between the sealing ring 4 and the retaining ring 5 can be achieved. In the depicted embodiments of the sealing assembly 2, 2', 2'', the sealing ring 4 has a slightly conical basic shape and a zigzag shaped cross-section. In the first place, the retaining ring 5, 5' ensures the dimensional stability and thus the ease of handling of the sealing assembly 2, 2', 2''. The sealing assembly can thus be mounted in the socket 1 by a machine. In addition, the retaining ring 5, 5' centres the spigot 3 in the socket 1. As a result, the socket 1 can be relatively short and does not have to be very accurately dimensioned. In the depicted embodiments of the sealing assembly 2, 2', 2'', the retaining ring 5, 5' supports part of the sealing ring 4 against the inside of the socket and ensures that the annular rib 6 is correctly retained. If the pipe parts are produced from a thermoplastic, they can be produced, for example, by injection-moulding or by extrusion. It is, however, also possible for the pipe parts to be wound or pressed and to consist of fibre-reinforced thermosetting plastic. The socket can be a socket which is integrally moulded on a pipe or can form part of a fitting, such as a double insertion socket, a T-piece or a Y-piece. The invention is not limited to the embodiments of a pipe part having a socket and a sealing assembly which are described above and depicted in the drawing. Both the socket and the sealing ring, and also the retaining ring, can have a different form. It is, however, important that the sealing assembly be provided on the outside with an annular rib which projects outwards and is made of resilient material. This rib does not have to form part of the sealing ring.

Claims: Pipe part having at least one socket (1), into which a spigot (3) of another pipe part can be inserted, the socket (1) having a groove arranged on the inside of the socket at distance from the free end of the socket and being provided on the inside with a separate, annular sealing assembly (2, 2', 2") comprising a sealing ring (4) made of an elastomeric material and having a sealing portion intended to provide the sealing between the socket (1) and the spigot (3) when the spigot is inserted into the socket (1), and a retaining ring (5, 5') made of a rigid material which is firmly connected to the sealing ring and which extends from the sealing ring towards and substantially as far as the free end of the socket, the sealing assembly being provided on the radial outside with an annular rib (6) which projects radially outwards, is made of resilient material and fits into the groove (7), characterized in that at least a portion of the annular rib (6) is arranged on the radial outside of the retaining ring (5, 5') and in that the sealing portion of the sealing ring (4) is arranged at an axial distance from the annular rib (6) and extends substantially in axial direction away from the annular rib (6) and the retaining ring (5) into a portion of the socket (1) located next to the groove (7) at the side of the groove facing away from the free end of the socket. Pipe part according to claim 1, wherein the annular rib (6) forms a part of the sealing ring (4) and is arranged in the region of the connection between the sealing ring and the retaining ring (5, 5'). Pipe part according to claim 1 or 2, wherein the retaining ring (5, 5') is provided at its end connected to the sealing ring (4) with a tapered portion. Pipe part according to anyone of claims 1 to 3, wherein the retaining ring (5) is provided, at least in the vicinity of the connection to the sealing ring (4), with a thin layer (11) which consists of the same material as the sealing ring (4) . Pipe part according to anyone of claims 1 to 4, wherein the sealing portion of the sealing ring (4) has a slightly conical basic shape and a zigzag shaped cross-section. Annular sealing assembly (2, 2', 2") comprising a sealing ring (4) made of an elastomeric material and having a sealing portion intended to provide the sealing between a socket of a pipe part and a spigot when the spigot is inserted into the socket, and a retaining ring (5, 5') made of a rigid material which is firmly connected to the sealing ring and which extends in axial direction away from the sealing ring (4), the sealing assembly being provided on the radial outside with an annular rib (6) which projects radially outwards and is made of resilient material, at least a portion of the annular rib (6) being arranged on the radial outside of the retaining ring (5, 5'), the sealing portion of the sealing ring (4) being arranged at an axial distance from the annular rib (6) and extending in substantially axial direction away from annular rib (6) and the retaining ring (5). Sealing assembly according to claim 6, wherein the annular rib (6) forms a part of the sealing ring (4) and is arranged in the region of the connection between the sealing ring and the retaining ring (5, 5'). Sealing assembly according to claim 6 or 7, wherein the retaining ring (5, 5') is provided at its end connected to the sealing ring (4) with a tapered portion. Sealing assembly according to anyone of claims 6 to 8, wherein the retaining ring (5) is provided, at least in the vicinity of the connection to the sealing ring (4), with a thin layer (11) which consists of the same material as the sealing ring (4) . Sealing assembly according to anyone of claims 6 to 9, wherein the sealing portion of the sealing ring (4) has a slightly conical basic shape and a zigzag shaped cross-section.

Inventors: KANTERS ARNOLDUS FRANCISCUS CO, PEDERSEN ERIK SEJR, KANTERS, ARNOLDUS FRANCISCUS CORNELIS, PEDERSEN, ERIK SEJR
Applicants: WAVIN BV, WAVIN B.V.
Application year: 1996
Main classification: F16L21
IPC codes: F16L21