A sealing device

Abstract: A sealing device for sealing a space established by connecting two sealing surfaces (42b, 52b) positioned on one element each of two elements (44b, 48b), for example two concrete pipes, to a position in which the sealing surfaces face each other comprises a sealing body (80) consisting of elastic material. The sealing body (80) is adapted at the connection of the sealing surfaces (42b, 52b) to take a position in the space in which it engages the sealing surfaces. The sealing device comprises an activating device (82 - 90) for forcing the sealing body (80) positioned in the space against the sealing surfaces (42b, 52b) when the activating device is activated.

Description: The present invention relates to a sealing device for sealing a space which is established by connecting two sealing surfaces positioned on one element each of two elements, for example two concrete pipes. It is previously known to seal a space formed by two opposite sealing surfaces on for example two concrete pipes by means of a sealing body consisting of elastic material. When the sealing surfaces are introduced one into the other to the position for establishing the space, the sealing body will take a position contacting the sealing surfaces in the space for closing and sealing the space. The sealing device of the kind described can be used for example in connection with concrete pipes of the type provided with a socket and a spigot end, the sealing surfaces being provided at a substantially cylindrical, inner surface of the socket and a substantially cylindrical, outer surface of the spigot end. The space between the sealing surfaces is established by introducing the pipes one into the other in the axial direction and in a substantially concentric position in relation to each other, whereby the sealing body which has previously been positioned either at the sealing surface of the socket or at the sealing surface of the spigot end will take the position in the space, in which it contacts the sealing surface. In order to make sure that the space is sealed in a correct way, it is necessary that the sealing body subsequently to the completing of the joint comprising the sealing surfaces and the sealing body contacts the sealing surfaces with sufficient sealing force. Sufficient sealing force is provided by the fact that the sealing body is in a predetermined degree compressed in the space because of the fact that the seating body has in a direction transversely of the sealing surfaces prior to the positioning of the sealing ring in the space larger dimensions than the space. If the compression of the sealing body in the space is provided as a consequence of the introduction of the sealing surfaces one into the other there are contradictory wishes with regard to the magnitude of the compression. Thus, it is desirable that the compression shall be large so as to secure the tightness of the joint, while it is desirable that the compression shall be small so as to make sure that the jointing force necessary for introducing the sealing surfaces one into the other shall not be of such a magnitude that there will be problems in providing the pipe jointing. In a sealing device for concrete pipes this problem is accentuated as the deviations of the dimensions of the concrete pipes from nominal values are often relatively large which provides that the dimensions of the space can vary in one and the same pipe joint as well as between different pipe joints within relatively wide limits. This means that the compression will be substantial in a space having minimum dimensions as the sealing body has to be dimensioned so that the compression is of sufficient size for securing the tightness of the joint also in a space having maximum dimensions. In order to solve this problem it is known to provide a sealing device of the type described above with an activating device for forcing the sealing body positioned in the space against the sealing surfaces when it is activated. Sealing devices of this kind are previously known from DE-U-91 12 112 and FR-A-2 166 593. In a sealing device of this kind the sealing body can be dimensioned so that the jointing force when introducing the sealing surfaces one into the other is low because of the fact that the dimensions of the sealing body transversely of the sealing surfaces exceed the dimensions of the space only in moderate degree and the fact that the sealing body is subsequently to the establishment of the space forced against the sealing surfaces by means of the activating device so that the tightness of the joint is secured also in such cases where the dimensions of the space in a substantial degree deviate from the nominal value. The object of the invention is to provide an improved sealing device of the kind described above. In order to comply with this object the activating device is constituted by an expansion device which is adapted at the activation of the activating device to force a pressure medium into a cavity provided in the sealing body to expand the cavity in a direction transversely of the sealing surfaces in order to force the sealing body against the sealing surfaces. In this case the expansion device for forcing a pressure medium into the cavity of the sealing body can comprise a member which contains the pressure medium and has a channel which at its end portion is connected with the cavity of the sealing body. In an embodiment of the sealing device according to the invention said channel is connected with an element which is positioned in the cavity of the sealing body and is expandable by the supply of the pressure medium. It is suitable that the activating device is adapted to be activated as a consequence of the connection of the sealing surfaces with each other, In the sealing device according to the invention the requirement for a low jointing force as well as the requirement for a high sealing force against the sealing surfaces are satisfied at the same timé as it is in the preferred embodiments of the sealing device according to the invention possible in an automatic way to activate the activating device of the sealing device by means of the movement necessary for establishing the joint. A number of different embodiments of the sealing device according to the invention shall be described in the following with reference to the accompanying drawings. Figs. 1a and 1b show sections of an embodiment of a sealing device according to the invention for sealing a pipe joint, in which Fig, 1a shows the sealing device prior to the establishment of the pipe joint and Fig. 1b shows the sealing device subsequently to the establishment of the pipe joint with an activating device included in the sealing device being shown in a activated position. Figs. 2a and 2b show sections corresponding to Figs. 1a and 1b of a modified embodiment of the sealing device according to the invention. Figs. 3a and 3b show sections of a further embodiment of a sealing device according to the invention in a pipe joint prior to the establishment of the pipe joint and subsequently to the establishment of the pipe joint. In Figs. 1a and 1b there is shown a pipe joint between two concrete pipes, one forming a socket 44b and the other forming a spigot end 48b. In the figures there is shown only sections of the walls of the pipes, while it is recognized that the pipes are in a conventional way of substantially cylindrical shape. The socket 44b has a sealing surface 42b, and the spigot end 48b has a sealing surface 46b, both being of substantially cylindrical shape and together defining a space 40b. The space 40b is established by displacing the sealing surfaces 42b and 46b together in an axial direction which is provided by displacing the pipes one into the other in a substantially concentric position. Thereby, the pipes can be positioned either in a horizontal position or in a vertical position, the pipes being in the last mentioned case constituted by well rings for forming a manhole. The sealing device according to Figs. 1a and 1b comprises a sealing ring 76 having a retainer portion 78 and a sealing body 80. In addition thereto, the sealing device comprises an activating device 82 which is connected with the sealing body 80 by means of a connection portion 84. The activating device 82 rests on the surface 62b of the spigot end 48b. The sealing body 80 is formed with a peripherally extending cavity 86 which through a channel 88 formed in the connection portion 84 is connected with a cavity 90 formed in the activating device 82. The cavities 86 and 90 contains a pressure medium which for example can be constituted by silicone paste, any curable material or a liquid, for example a mixture of glycol and water. When the socket 44b is lowered towards the spigot end 48b for establishing the space 40b between the sealing surfaces 42b and 46b, the sealing body 80 is initially subjected to a moderate compression which facilitates the jointing movement as a consequence of a small jointing force. When the surface 60b of the socket 44b arrives into engagement with the activating device 82, the cavity 90 is compressed and the pressure medium therein is through the channel 88 forced into the cavity 86 in the sealing body 80. Thereby, the sealing body 80 will obtain a increased sealing force against the sealing surfaces 42b and 46b. Thus, there is provided an automatic activation of the activating device for providing an increased sealing pressure against the sealing surfaces in the space. The embodiment of the sealing device according to the invention shown in Figs. 2a and 2b is in in substantial agreement with the emodiment according to Figs. 1a and 1b, and the same reference numerals are used in Figs. 2a and 2b as well as in Figs. 1a and 1b. In the embodiment according to Figs. 2a and 2b the activating device 82 is provided with a connection 92 by means of which it is possible afterwards to supply pressure medium to the cavity 86 in the sealing body 80 through the cavity 90 and the channel 88 in order afterwards to increase the sealing pressure, if desired. The embodiment of the sealing device according to the invention shown in Figs. 3a and 3b is inteded to be used at a socket and a spigot end of the same kind as the socket and the spigot end according to Figs. 1a and 1b. In Figs. 3a and 3b the socket and the spigot end as well as the different surfaces of the socket and the spigot end are designated with the same reference numerals as in Figs. 1a and 1b with the addition of "c" instead of "b". The sealing device according to Figs. 3a and 3b comprises a sealing ring 94 having a double sliding skin 96. The sealing ring 94 rests on the shoulder 54c of the spigot end 48c and is provided with a cavity 98 at its lower surface. In addition to the sealing ring 94 the sealing device comprises an activating device 100 having an annular main portion 102 consisting of elastic material and peripherally extending, enclosing portion 104 of harder material than the main portion 102. In the main portion 102 there is provided a cavity 106 which through a hose 108 is connected with an annular expansion body 110 positioned in the cavity 98 of the sealing ring 94. The cavity 106 is filled with a pressure medium which as in the embodiments described above can be constituted by a silicone paste, any curable medium or a liquid, for example a mixture of glycol and water. When the sealing surfaces 42c and 46c are connected with each other by lowering the socket 44c against the spigot end 48c there is provided a moderate compression of the sealing ring 94, the connection being facilitated by the fact that the sliding skin 96 which preferably contains a sliding medium engages the sealing surface 42c while an inner sliding takes place. When the surface 56c of the socket 44c contacts the activating device 100 the pressure medium is forced out from the cavity 106 and is supplied to the expansion body 110 through the hose 108, which provides that the sealing ring 94 is forced against the sealing surfaces in a direction transverse to the sealing surfaces 42c and 46c. Thus, also in this embodiment there is provided an automatic activation of the activating device 100 as a consequence of the connection of the socket and the spigot end with each other.

Claims: A sealing device for sealing a space which is established by connecting two sealing surfaces (42; 46) positioned on one element each of two elements (44; 48), for example two concrete pipes, into a position facing each other, comprising a sealing body (80; 94) consisting of elastic material and adapted at the connection of the sealing surfaces to take a position in the space in which it contacts the sealing surfaces, and further comprising an activating device (82; 100) for forcing the sealing body (80; 94) positioned in the space against the sealing surfaces (42;46) when the activating device is activated, characterized in that the activating device is constituted by an expansion device (82; 100) which is adapted at the activation of the activating device to force a pressure medium into a cavity (86; 98) provided in the sealing body (80; 94) to expand the cavity in a direction transversely of the sealing surfaces (42; 46) in order to force the sealing body against the sealing surfaces. A sealing device as claimed in claim 1, characterized in that the expansion device (82; 100) for forcing a pressure medium into the cavity (86; 98) of the sealing body (80; 94) comprises a member (82; 100) containing the pressure medium and having a channel (88; 108) which at its end portion is connected with the cavity (86; 98) of the sealing body (80; 94). A sealing device as claimed in claim 2, characterized in that the channel (108) is connected with an element (110) which is positioned in the cavity (98) of the sealing body and is expandable by the supply of the pressure medium. A sealing device as claimed in any of the preceding claims, characterized in that the activating device (82; 100) is adapted to be activated as a consequence of the connection of the sealing surfaces (42; 48) with each other. A sealing device as claimed in claim 4, characterized in that the activating device (82; 100) is adapted to be activated as a consequence of an engagement with at least one surface (56; 60) of the elements on which the sealing surfaces (42; 46) are positioned. A sealing device as claimed in claim 5, in which the sealing surfaces (42; 46) are adapted to be connected with each other in a direction parallel with the sealing surfaces, characterized in that the activating device (82; 100) is adapted to be activated as a consequence of an engagement with at least one surface (56; 60) extending transversely of the sealing surfaces (42; 46). A sealing device as claimed in claim 6, characterized in that the activating device (82) is adapted to be activated as a consequence of being compressed between two surfaces (56; 58; 60; 62) extending transversely of the sealing surfaces (42; 46). A sealing device as claimed in claim 2 and 7, characterized in that the device for forcing a pressure medium into the cavity of the sealing body is adapted to be activated by compression of the element (82; 100) containing the pressure medium between the two surfaces (56; 58; 60; 62) extending transversely of the sealing surfaces (42; 46).

Inventors: ANDERSSON JOAKIM, CAVKA ELVIR, EKHOLM KENNET, FORSBERG SOEREN, HOLMEN BENT, LEPPIMAEKI MIKA, MEHL HELMUT, NEUMANN WIELAND, NILSSON ULF, ANDERSSON, JOAKIM, CAVKA, ELVIR, EKHOLM, KENNET, FORSBERG, SOEREN, HOLMEN, BENT, LEPPIMAEKI, MIKA, MEHL, HELMUT, NEUMANN, WIELAND, NILSSON, ULF, Forsberg, Sören, Leppimäki, Mika
Applicants: FORSHEDA AB
Application year: 1996
Main classification: F16L17
IPC codes: F16L17, F16J15, F16L21