A SEALING DEVICE

Abstract: A sealing device for sealing a joint which is constituted by two sealing surfaces (26, 28) facing each other. The sealing surfaces are displaceable in parallel in relation to each other. The sealing device comprises a sealing element (30) consisting of elastomeric materials of at least two different hardnesses. The sealing element (30) is compressed in the joint while contacting the sealing surfaces. The sealing element (30) forms two portions (32) of elastomeric material having low hardness, said portions (32) contacting the sealing surfaces (26, 28). The elastomeric material having high hardness (34) is positioned between the portions having low hardness and contacting the sealing surfaces. The elastomeric material having high hardness (34) is adapted at parallel displacement of the sealing surfaces (26, 28) from the position for forming the joint to increase its size in a direction transversely in relation to the sealing surfaces.

Description: A sealing device The present invention relates to a sealing device for sealing a joint constituted by two sealing surfaces facing each other. The sealing device according to the invention is intended for sealing a joint in which the sealing surfaces are displaceable in parallel with each other. Such a joint can for example be constituted by a joint between two pipe end portions in which the pipe end portions are provided with a socket and a spigot end and the joint is constituted between the substantially cylindrical inner surface of the socket and the substantially cylindrical outer surface of the spigot end introduced into the socket. The sealing device according to the invention comprises a sealing element formed by elastomeric materials of at least two different hardnesses, the sealing element being compressed in the joint while contacting the sealing surfaces. In a sealing device of said kind it is desirable that the sealing device shall prevent or at least counteract displacement of the sealing surfaces from the position in which the sealing surfaces form said joint. In a pipe joint for this purpose it is previously known to use a roller sealing ring having a drop-shaped cross-section, the roller seal- ing ring having subsequently to the establishment of the pipe joint its smallest dimension positioned transversely to the sealing surfaces in the joint between the sealing surfaces. When making an attempt to displace the sealing surfaces from the position in which the sealing surfaces constitute the joint there is established a resistance because of the fact that the sealing ring rolls against a position in which it has its largest dimensions of the cross-section. The object of the invention is to provide an improved sealing device of the kind which prevents or obstructs displacement of the sealing surfaces from the position in which the sealing surfaces form the joint. In order to comply with this object the sealing device according to the invention is characterized by the fact that the sealing element forms two portions of elastomeric material having low hardness, said portions engaging the sealing surfaces, that the elastomeric material having high hardness is positioned between the portions having low hardness and contacting the sealing surfaces and that the elastomeric material having high hardness is adapted at parallel movement of the sealing surfaces from the position for forming the joint to increase its size in a direction transversely in relation to the sealing surfaces. In a sealing device of this kind the efficiency of the sealing device is improved with regard to the sealing of the joint as well as the capacity of preventing parallel displacement of the sealing surfaces from the position in which the sealing surfaces form the joint. The improved sealing efficiency is provided by the fact that the sealing element contacts and engages the sealing surfaces with elastomeric material having low hardness which provides that the sealing element closely adapts to irregularities of the sealing surface and in spite of such irregularities provide for an efficient sealing. Because of the fact that the elastomeric material having high hardness is used for preventing a parallel displacement of the sealing surfaces from the position forming the joint such displacement is prevented with greater efficiency. In previously known sealing devices one has been referred to provide a compromise between low hardness of the elastomeric material for providing an efficient sealing and a high hardness of the elastomeric material in order to prevent said displacement of the sealing surfaces from the position in which the sealing surfaces define the joint. The sealing device according to the invention can be designed in different ways. In one embodiment the elastomeric material having high hardness forms two portions which at the displacement of the sealing surfaces from the position for forming the joint are displaced towards each other and by acting on each other are displaced against one sealing surface each. Thereby the portions having high hardness can be adapted to act on each other by cooperation between substantially parallel, concentric, conical surfaces. In another embodiment of the sealing device according to the invention the elastomeric material having high hardness forms one or several portions which in section have different dimensions in different directions. Thereby, the sealing device is adapted at displacement of the sealing surfaces from the position for forming the joint to change its position from a position in which the elastomeric material portions having high hardness present small dimensions perpendicular to the sealing surfaces into a position in which the portions having high hardness present larger di- mensions perpendicular to the sealing surfaces. In this embodiment the elastomeric material having high hardness can in the sealing element form a portion formed as a layer or several portions formed as layers. In the position in which the sealing surfaces form the joint the portions forming the layers take a position in which they are substantially parallel with the sealing surfaces. At an attempt to displace the sealing surfaces from the position in which the surfaces define the joint the portions forming the layers are rotated towards a position in which the layers take a more transverse relationship to the sealing surfaces which prevents or counteracts the displacement of the sealing surfaces from the position in which they form the joint. In another embodiment of the sealing device according to the invention the sealing surfaces have sections with greater and smaller distances between the sealing surfaces. Thereby, the portion consisting of elastomeric material with great hardness is adapted at the parallel displacement of the sealing surfaces from the position for forming the joint to be displaced from a section having a large distance between the sealing surfaces towards a section having less distance between the sealing surfaces. In this embodiment the sealing element can comprise a portion with a low hardness contacting one of the sealing surfaces and a portion connected therewith and foldable against this. Subsequently to the folding the foldable portion has a portion having low hardness contacting the other sealing surface and a portion with high hardness positioned between the portions having low hardness. The sealing device according to this embodiment is especially well suited to be used in a joint between a socket and a spigot end of two pipe end portions. In the sealing device according to the invention it is also possible to design the elas- tomeric material having high hardness as one or several portions which are folded when the sealing surfaces are displaced in parallel to the position for forming the joint. Thereby these foldable portions will take a somewhat folded position in the joint. When the sealing surfaces are displaced in parallel from the position for forming the joint this displacement is counteracted by the fact that the folded portions are displaced towards a raised-up position. In the last-mentioned embodiment the elas ¬ tomeric material having high hardness can have for example an L-shaped, a U- shaped, an l-shaped or a T-shaped cross-section. Some different embodiments of the sealing device according to the invention shall in the following be described with reference to the accompanying drawings. Figs 1-3 show different embodiments of the sealing device according to the invention in which the sealing device is included in a pipe joint constituted by a socket and a spigot end. Figs 4a and 4b show a further embodiment of a sealing device according to the invention included in a pipe joint constituted by a socket and a spigot end, in which fig. 4a shows the sealing element included in the sealing device in a first position prior to the establishment of the pipe joint and fig. 4b shows the sealing device subsequently to the establishment of the pipe joint. Figs 5-8 show further embodiments of the sealing device according to the invention in which the sealing device is included in a pipe joint constituted by a socket and spigot end. Fig. 1 shows a part of a socket 2 and a spigot end 4 introduced therein, in which the socket 2 has an inner, substantially cylindrical sealing surface 6 and the spigot end 4 has an outer, also substantially cylindrical sealing surface 8. The joint between the sealing surfaces 6 and 8 is sealed by means of a sealing element in the form of a sealing ring 10 consisting of a portion 12 of soft rubber and two portions 14 and 16 of hard rubber. The sealing ring 10 is compressed between the sealing surfaces 6 and 8, and the soft rubber of the portion 12 provides for good tightness even if the sealing surfaces are provided with irregularities. The portions 14 and 16 of the sealing ring and consisting of hard rubber have the object of preventing that the joint comprising the sealing surfaces 6 and 8 and the sealing ring 10 is separated by displacing the spigot end 4 out of the socket 2. Prior to the establishment of the pipe joint the sealing ring 10 is tensioned onto the sealing surface 8 of the spigot end 4, and when the spigot end 4 is introduced into the socket 2 the sealing ring 10 is compressed between the sealing surfaces 6 and 8. During the introduction of the spigot end 4 into the socket 2 the portions 14 and 16 consisting of hard rubber are displaced from each other which facilitates the introduction of the spigot end 4 into the socket 2. At attempts to displace the spigot end 4 out from the socket subsequently to the pipe jointing the portions 14 and 16 consisting of hard rubber are displaced towards each other, the conical surfaces 18 and 20 of the portions 14 and 16 thereby providing that the portions 14 and 16 are displaced against one of the sealing surfaces 6 and 8 each. This provides for an increased pressing of the soft rubber of the portion 12 against the sealing surfaces which pre- vents that the spigot end 4 is moved out of the socket 2. Also the sealing device shown in fig. 2 is positioned between a socket 22 and a spigot end 24 introduced therein. The socket 22 has an inner, cylindrical sealing surface 26 and the spigot end 24 has an outer, cylindrical sealing surface 28. A sealing element in the form of a sealing ring 30 is positioned between the sealing surfaces 26 and 28, the sealing ring having two portions 32 of soft rubber and a layer 34 of hard rubber positioned between the portions 32. At an attempt to move the spigot end 24 out from the socket 26 the sealing ring 30 rotates which provides that the layer 34 of hard rubber is rotated towards a position transversely in relation to the sealing surfaces 26 and 28 which prevents or at least to a large extent counteracts the movement of the spigot end 24 from the socket 26. The embodiment of the sealing device according to the invention shown in fig. 3 is in substantial agreement with the embodiment according to fig. 2 with the difference that the sealing ring 30 instead of one layer of hard rubber has three parallel layers 36 of hard rubber. The function of the sealing ring 30 in the embodiment according to fig. 3 is in substantial agreement with the function of the sealing ring according to.the embodiment of fig. 2. Also the embodiment of the sealing ring according to the invention shown in fig. 4a the sealing ring is included into a socket 38 and a spigot end 40 in which the socket has an inner, cylindrical sealing surface 42 and the spigot end 40 has an outer cylindrical sealing surface 44. A sealing ring 46 is moulded into the socket 38 at the seal- ing surface 42 thereof, and the sealing ring 46 consists of two portions 48 and 50 of soft rubber and a portion 52 of hard rubber. The portion 48 of soft rubber is by means of retainer portions 54 moulded into the material forming the socket 38. Prior to the pipe jointing the portion 50 and the portion 52 connected therewith are folded against the portion 48 of the sealing ring to the position shown in fig. 4b, in which the portion 52 of hard rubber engages the portion 48 of soft rubber. Subsequently to the introduction of the spigot end 40 into the socket 38 the sealing ring 46 is compressed between the sealing surfaces as shown in fig. 4b. The sealing surface 42 forms a groove 56 in which the sealing ring is received and at an attempt to dis- place the spigot end 40 from the socket 38 the portion 52 of hard rubber of the sealing ring 46 will prevent or to a large extent counteract the withdrawal of the spigot end from the socket by the fact that the portion 52 is displaced towards the inwardly directed, annular portion 58 of the sealing surface 42. The embodiment of the sealing device according to the invention shown in fig. 5 comprises a socket 60 having an inner, substantially cylindrical sealing surface 62 and a spigot end 64 having an outer, substantially cylindrical sealing surface 66. A sealing ring 68 is compressed between the sealing surfaces 62 and 66. The sealing ring 68 has a portion 70 consisting of soft rubber and a U-shaped portion 72 consist- ing of hard rubber. The U-shaped portion 72 has a web portion 74 and two legs 76 extending outwardly therefrom. Prior to the pipe jointing the legs 76 extend perpendicular to the web portion 74 but in connection the pipe jointing, i.e. when the spigot end 64 is introduced into the socket 60, the legs 76 are folded to the position shown in fig. 5. At an attempt to withdraw the spigot end 64 from the socket 60 this is prevented or counteracted by the fact that the legs 76 are thereby straightened out against a perpendicular position in relation to the web portion 74 which increases the dimensions of the sealing ring transversely in relation to the sealing surfaces 62 and 66. Also the embodiment of the sealing device according to the invention shown in fig. 6 is positioned in a joint between a socket 78 having an inner, cylindrical sealing surface 80 and a spigot end 82 having an outer, substantially cylindrical sealing surface 84. A sealing ring 86 is compressed between the sealing surfaces 80 and 84. The seating ring 86 consists of a portion 88 of soft rubber and a l-shaped portion 90 of hard rubber positioned in the portion 88. The portion 90 has two portions 92 which extend parallel with the sealing surfaces 80 and 84 and a portion 94 connecting the portions 92 and extending prior to the pipe jointing transversely in relation to the seal- ing surfaces 80 and 84. At the pipe jointing the portion 94 is deflected as shown in fig. 6, and at an attempt to withdraw the spigot end 82 from the socket 78 this is prevented or at least counteracted by the fact that the portion 94 acts for being stright- ened from its bent position. Also the embodiment of the sealing device according to the invention shown in fig. 7 is included into a socket 96 having an inner, cylindrical sealing surface 98 and a spigot end 100 having an outer, cylindrical surface 102 introduced into the socket 96. A sealing ring 104 is compressed between the sealing surfaces 98 and 102. The sealing ring 104 comprises a portion 106 consisting of soft rubber and an L-shaped portion 108 consisting of hard rubber and positioned in the portion 106. The portion 108 has a portion 110 extending parallel with the sealing surface 102 and a portion 112 which prior to the pipe jointing forms a right angle with the portion 110. Subsequently to the pipe jointing the portion 112 takes a deflected position as shown in fig. 7. At an attempt to withdraw the spigot end 100 from the socket 96 this is prevented or counteracted by the fact that the portion 110 acts for being straightened and thereby increases its dimensions in a direction transversely of the sealing surfaces 98 and 102. Also the embodiment of the sealing device according to the invention shown in fig. 8 is included into a socket 114 having an inner, cylindrical sealing surface 116 and a spigot end 118 having an outer, substantially cylindrical sealing surface 120. A sealing ring 122 is compressed between the sealing surfaces 116 and 120. The sealing ring 122 has a portion 124 consisting of soft rubber and a portion 126 consisting of hard rubber and having a cross-shaped section. Prior to the pipe jointing one of the parts 128 extends transversely in relation to the sealing surfaces 116 and 120 while the other portion 130 extends in parallel with the sealing surfaces 116 and 120. Subsequently to the pipe jointing the portion 126 of hard rubber takes the position shown in fig. 8 and at an attempt to withdraw the spigot end 118 from the socket 114 the hard rubber portion 126 acts for returning to the position prior to the pipe jointing, i.e. the portion 128 increases its dimension in a direction transversely of the sealing surfaces 116 and 120 which prevents or least counteracts said withdrawal of the spigot end. In the device according to the invention the engagement of the soft elastic material of the sealing elements provide for a good sealing efficiency at the same time as the sealing elements prevent that the sealing surfaces are displaced from the position for forming the joint. The invention can be modified within the scope of the following claims.

Claims: CLAIMS 1. A sealing device for sealing a joint constituted by two sealing surfaces facing each other, the sealing surfaces being displaceable in parallel with each other, comprising a sealing element which is compressed in the joint and consists of elastomeric materials of two different hardnesses, characterized in that the sealing element forms two portions which consist of elastomeric material with a low hardness and engage the sealing surfaces, that the elastomeric material with high hardness is positioned between the portions having low hardness and engaging the sealing surfaces and that the elastomeric material having high hardness is adapted at parallel displacement of the sealing surfaces from the position for forming the joint to increase its size in a direction transversely in relation to the sealing surfaces. 2. A sealing device as claimed in claim 1, characterized in that the elastomeric material having high hardness forms two portions which at displacement of the sealing surfaces from the position for forming the joint are displaced towards each other and by actuating each other are displaced against one sealing surface each. 3. A sealing device as claimed in claim 2, characterized in that the portions having high hardness are adapted to actuate each other by cooperation between substantially parallel, concentric, conical surfaces. 4. A sealing device as claimed in claim 1, characterized in that the elastomeric material having high hardness forms one or several portions the sections of which have different dimensions in different directions and that the sealing device is adapted at displacement of the sealing surfaces from the position for forming the joint to change its positions from a position in which the elastomeric material portions having high hardness present small dimensions transversely in relation to the sealing surfaces towards a position in which the portions having high hardness present larger dimensions transversely in relation to the sealing surfaces. 5. A sealing device as claimed in claim 4, characterized in that the elastomeric material having high hardness forms in the sealing element a part formed as a layer or several parallel layers. 6. A sealing device as claimed in claim 4, characterized in that the elastomeric material having high hardness forms a portion having cross-shaped section. 7. A sealing device as claimed in claim 1, characterized in that the seal- ing surfaces have sections with larger and smaller distances between the sealing surfaces and that the portion of elastomeric material having high hardness is adapted at parallel displacement of the sealing surfaces from the position for forming the joint to be displaced from a section having a large distance between the sealing surfaces towards a section having less distance between the sealing surfaces. 8. A sealing device as claimed in claim 7, ch a racterized in that the sealing element comprises a portion having a low hardness and contacting one sealing surface and a portion connected with an edge of said portion and be- ing foldable, the foldable portion having subsequently to the folding a portion having low hardness and contacting the other sealing surface and a portion with high hardness positioned between the portions with low hardness. 9. A sealing device as claimed in claim 8, in which the joint is constituted be- tween two substantially concentric and substantially cylindrical surfaces at two pipe end portions, ch a racte rized in that the portion having low hardness and contacting one of the sealing surfaces is moulded into the material forming this sealing surface. 10. A sealing device as claimed in claim 9, ch a ra cte rized in that the portion having low hardness and contacting one of the sealing surfaces is moulded into a sealing surface of a pipe socket with the foldable portion positioned at the edge section of the sealing surface of the socket and that a spigot end provided with the other sealing surface is subsequently to folding of the foldable portion into the socket introduceable into the socket for providing a compression of the sealing element between the sealing surfaces of the socket and the spigot end. 11.A sealing device as claimed in claim 1 , characterized in that the elas- tomeric material with high hardness forms one or several portions which are foldable at the parallel displacement of the sealing surfaces towards the position for forming the joint, said portions taking in the joint a somewhat folded position, the portion or the portions having a folded position obstructing parallel displacement of the sealing surfaces from the position for forming the joint by being displaced from a folded towards a raised position. 12. A sealing device as claimed in claim 11, c h a racte rized in that the elastomeric material having high hardness has an L-shaped cross-section, one leg extending substantially parallel with the sealing surfaces and the other leg extending substantially transversely in relation to the sealing surfaces prior to the establishment of the pipe joint. 13. A sealing device as claim in claim 11, characterized in that the elastomeric material having high hardness is of U-shaped cross-section, the web portion extending substantially parallel with the sealing surfaces and the two legs extending substantially transversely in relation to the sealing surfaces prior to the establishment of the pipe joint. 14. A sealing device as claimed in claim 11, c h a racte rized in that the elastomeric material having high hardness is of l-shaped cross-section, the vertical part of the I extending substantially parallel with the sealing surfaces or substantially transversely in relation to the sealing surfaces and the horizontal parts of the I extending substantially transversely in relation to the sealing surfaces and substantially parallel with the sealing surfaces, respectively. 15. A sealing device as claimed in claim 11, c h a ra ct e ri zed in that the elastomeric material having high hardness is of T-shaped cross-section, the vertical part of the T extending substantially parallel with the sealing surfaces or substantially transversely in relation to the sealing surfaces and the hori- zontal part of the T extending substantially parallel with the sealing surfaces and substantially transversely in relation to the sealing surfaces, respectively.

Inventors: SPORRE STEN, SPORRE, STEN
Applicants: ENEBACKEN SKREA AB, SPORRE STEN, SPORRE, STEN
Application year: 2000
Main classification: F16L21
IPC codes: F16L21