SEAL

Abstract: A pipe seal for fitting in a groove (2) in the side wall of one plastic pipe (3) to engage and seal with a seamed plastic pipe (11) inserted inside the first, comprises a resiliently deformable annular carrier (1) and an annular sealing member (7) attached to the carrier (1). A flange (17) extends axially from the sealing member (7) and engages one radial side wall (10) of the groove (2). The carrier (1) is preferably U-shaped with one arm (4) in the base of the groove extending axially to engage the other radial side wall of the groove (2). The arm (4) in the base of the groove (2) is longer than the other arm (5) of the U-shape. A flange (12) extends axially from the sealing member in the base of the groove to engage said radial side wall (10) and stands proud of the carrier (1) to engage the base (9) of the groove (2). A flange (15) extends radially inwardly from the sealing member (7) to engage the second pipe (11), and has an inclined face (16) for engagement by the end of the pipe (11) as it is inserted.

Description: SEAL This invention relates to pipe seals, especially pipe seals for unpressurised joints between plastic pipes with a preformed groove for the seal. Pipe seals are ring shaped elastomer seals that are located in a groove in one pipe or pipe fitting that is to be connected with a second pipe or pipe fitting, with the seal located circumferentially between the two pipes. Generally, a pipe seal must be made within specified tolerances to fit a particular size of pipe and groove. An object of the invention is to provide an improved pipe seal that can fit a range of groove sizes. The seal according to the invention comprises a resiliently deformable annular carrier and an annular sealing member attached to the carrier so as to form a seal between concentric pipes when located in a groove therebetween, the sealing member having a portion which extends axially so as to engage a radially extending side wall of the groove, with the carrier in engagement with an opposite side wall of the groove. Preferably, said opposite side wall of the groove is inclined so that contact with the carrier as the latter is urged radially into the groove serves to urge the carrier axially towards said side wall of the groove engaged by the sealing member. For example, said opposite side wall may have a curved portion which forms a rounded corner with the base of the groove. Preferably, the carrier comprises a U-section member which is received within the depth of the groove with the two arms of the U-section extending axially of the groove. That arm in the base of the groove extends axially further than the other arm so as to engage the adjacent side wall of the groove, and thereby locate the seal axially. Typically, the carrier is composed of a plastics material. Preferably, the sealing member is located generally on that side of the carrier opposite the open channel of the U-section, and has a flange that extends axially sufficiently to engage the adjacent side wall of the groove and bend back on itself so as to be urged into sealing engagement with the side wall. The length of the flange in relation to the overall width of the seal is selected to accommodate a range of groove widths. The sealing member also has portions that extend radially inwardly and outwardly of the carrier to seal with the base of the groove on the one side, and seal with the pipe on the other side. That portion that seals with the base of the groove may comprise an axially extending annular flange with a side face that stands radially proud of the carrier to engage the base of the groove in face-to-face contact. That portion that seals with the pipe may comprise a radially extending flange with an inclined face to engage with, and be deflected by, the pipe when both pipes are fitted together. According to a further feature of the invention, the axially extending flange that seals with the side wall of the groove is aligned with the open channel in the U-section carrier so that multiple seals can be stacked together with the flange of one engaging the channel in another carrier. The invention will now be described by way of example with reference to the accompanying drawings. Figure 1 shows a section through a pipe seal according to the invention. Figure 2 shows the pipe seal of Figure 1 inserted into a groove in a pipe. Figure 3 shows the pipe seal of Figure 2 with a second pipe inserted into the first, past the seal. Figure 4 is similar to Figure 3 and shows the pipe seal fitted into a wider groove than that of Figure 3, and Figure 5 shows a number of pipe seals according to the invention which are stacked axially together. The illustrated pipe seal comprises a U-section carrier 1 composed of a semi-rigid plastics material such that the carrier can be resiliently deformed for insertion into an internal groove 2 of a plastic pipe 3, and will resume its normal shape when released. The two arms 4, 5 of the U-section extend axially, and the outermost arm 4 is the longer, and its tip is adapted to engage an adjacent side wall 6 of the groove 2 to locate the seal axially. An elastomeric sealing member 7 is bonded to the carrier 1 as an integral part of the seal, on that side of the carrier opposite the open channel 8 of the U-section. The sealing member 7 has three principle portions 12, 15 and 17 that seal respectively with the base 9 of the groove, the second pipe 11 that is inserted into the first pipe 3, and the adjacent side wall 10 of the groove. The first portion 12 of the sealing member that seals with the base of the groove takes the form of a flange which extends axially away from the carrier and stands proud of the outer surface 13 of the carrier so as to engage the base of the groove. This flange 12 is formed with a series of circumferential grooves 14 in its outer surface so as to produce additional sealing lips to engage the base of the groove. The second portion 15 of the sealing member which engages the second pipe 11 comprises a radially inwardly extending flange with an inclined face 16 directed towards the open end of the first pipe 3 so as to be engaged and deflected by the end of the second pipe 1 1 when it is inserted, as shown in Figures 2 and 3. This deflection of the flange 15 creates a compressive load within it which serves to maintain the sealing action between the two pipes. The third portion 17 of the sealing member extends axially away from the carrier between the first and second flanges 12, 15 in substantially axial alignment with the open channel 8 in the carrier. If this third flange 17 is long enough to engage the adjacent side wall 10 of the groove and bend when inserted into it, as shown in Figures 2 and 3, the bending stress serves to urge the flange 17 into sealing engagement with the side wall 10 of the groove. Also, internal pressurisation of the pipes, when in use, will pressurise the space between the second and third flanges 15, 17 and compress the sealing member in a manner which increases the sealing forces at the sealing surfaces. The outer face of the third flange 17 is tapered and formed with circumferential grooves 19 so as to increase its flexibility for insertion into the groove. As shown in Figure 4, a seal according to the invention can be fitted into a wider groove 2 and will still produce an effective sealing action. This is due to the fact that the extended length of the third flange 17 will still allow it to engage the adjacent side wall 10 of the groove, although it will not be folded back on itself to the same extent as it would with a narrower groove. Also, it will be appreciated that the curved corner 18 between the side wall 6 and the base 9 serves to urge the seal axially towards the side wall 10 as the seal is forced radially into the groove, thereby enhancing the sealing contact between the flanges 12 and 17 and the side wall 10. Finally, as illustrated in Figure 5, the seal according to the invention can be stored with multiple similar seals by stacking them together with the third flange 17 of each engaging the open channel 8 in the carrier 1 of an adjacent seal.

Claims: Claims 1. A pipe seal comprising a resiliently deformable annular carrier and an annular sealing member attached to the carrier so as to form a seal between concentric pipes when located in a groove therebetween, the sealing member having a portion which extends axially so as to engage a radially extending side wall of the groove, with the carrier in engagement with an opposite side wall of the groove. 2. A seal as claimed in claim 1 in which the carrier comprises a U-section member which is received within the depth of the groove with the two arms of the U-section extending axially of the groove. 3. A seal as claimed in claim 2 in which one arm in the base of the groove extends axially further than the other arm so as to engage the adjacent side wall of the groove and locate the seal axially. 4. A seal as claimed in claims 2 or 3 In which the sealing member is located generally on that side of the carrier, opposite the open channel to the U-section and has a flange that extends axially sufficiently to engage the adjacent side wall of the groove and bend back on itself to be urged into sealing engagement with the side wall. 5. A seal as claimed in any one of the preceding claims in which the sealing member has one portion that extends radially inwardly of the carrier to seal with the base of the groove. 6. A seal as claimed in claim 5 in which said one portion comprises an axially extending annular flange with a side face that stands radially proud of the carrier to engage the base of the groove in face-to-face contact. 7. A seal as claimed in claim 6 in which said axially extending annular flange is aligned with the open channel in the U-section carrier so that multiple seals can nest together in storage. 8. A seal as claimed in any one of claims 5 to 7 in which the sealing member has another portion that extends radially outwardly of the carrier to seal with an adjacent pipe. 9. A seal as claimed in claim 8 in which said other portion comprises a radially extending flange with an inclined face to engage, and be deflected by said adjacent pipe when inserted into the other concentric pipe. 10. A pipe seal as claimed in any one of the preceding claims in combination with a pipe having a side wall formed with an annular groove to receive the seal, the groove extending axially between two radially extending side walls and the axially extending portion of the sealing member engaging one of the side walls of the groove and the carrier engaging the other side wall of the groove. 11. A pipe seal and pipe combination as claimed in claim 10 in which said other side wall of the groove is inclined from the radial so that radial loading from the carrier serves to urge the carrier axially towards said one side wall engaged by the axially extending portion of the sealing member. 12. A pipe seal substantially as herein described with reference to the accompanying drawings

Inventors: CAVKA ELVIR, GUSTAFSSON LEIF, CAVKA, ELVIR, GUSTAFSSON, LEIF
Applicants: CAVKA ELVIR, FORSHEDA AB, GUSTAFSSON LEIF, HOGG JEFFERY KEITH, CAVKA, ELVIR, GUSTAFSSON, LEIF, HOGG, JEFFERY, KEITH
Application year: 2000
Main classification: F16L21
IPC codes: F16L21