EP1255946A1 - A gasket for securing pipes or pipe components - Google Patents
A gasket for securing pipes or pipe componentsInfo
- Publication number
- EP1255946A1 EP1255946A1 EP00940662A EP00940662A EP1255946A1 EP 1255946 A1 EP1255946 A1 EP 1255946A1 EP 00940662 A EP00940662 A EP 00940662A EP 00940662 A EP00940662 A EP 00940662A EP 1255946 A1 EP1255946 A1 EP 1255946A1
- Authority
- EP
- European Patent Office
- Prior art keywords
- socket
- heel
- segment
- bead
- gasket
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L37/00—Couplings of the quick-acting type
- F16L37/08—Couplings of the quick-acting type in which the connection between abutting or axially overlapping ends is maintained by locking members
- F16L37/084—Couplings of the quick-acting type in which the connection between abutting or axially overlapping ends is maintained by locking members combined with automatic locking
- F16L37/0845—Couplings of the quick-acting type in which the connection between abutting or axially overlapping ends is maintained by locking members combined with automatic locking by means of retaining members associated with the packing member
Definitions
- This invention relates to a gasket for securing pipes or pipe components to one another.
- each spigot end and socket end combination It is necessary to seal the joint defined by each spigot end and socket end combination, against the pressure of fluid such as water conveyed in the pipes. It is known for the pressure in metal water pipes to reach 16 bar in use. The pipes typically have to pass tests in which they are pressurised to 21 bar.
- each socket end with a radially inwardly extending flange defining an inwardly facing annular shoulder spaced a short distance axially inwardly of the free end of the socket.
- An annular bead e.g. of semi-circular profile, is formed a short axial distance further inward of the shoulder. The axial space between the shoulder and bead defines a groove known as a socket heel groove.
- Tyton anchor gasket One form of seal, that performs dual functions of sealing the joint and preventing axial separation of the pipes, is known as a Tyton anchor gasket.
- a known Tyton anchor gasket 10 is shown in cross section in Figure 1.
- FIG. 1 there is shown an annular elastomeric member 15 that is designed to seat about the socket heel groove and bead of a pipe socket end.
- Elastomeric member 15 has a portion 15a of substantially circular cross section that blends into a heel portion 15b of substantially rectangular cross section.
- the transition between portions 15a and 15b is a concave curvature 15c that is substantially congruent with the profile of the annular bead.
- the heel portion of the elastomeric member 15 is received in the socket heel groove, while the annular bead seats in concave portion 15c and the substantially circular cross section portion seals the gap between the spigot and socket pipe ends.
- a series of metal anchor segments 11 is secured in the elastomeric member about the annulus defined thereby.
- Each anchor segment 11 has a series of radially inwardly directed teeth 12a, 12b that protrude inwardly of the elastomeric member 15 for engagement with the spigot end.
- the tips of the teeth are angled towards the free end of the spigot end.
- each metal segment 11 Radially outwardly of the teeth 12a, 12b the upper edge of each metal segment 11 is concave in a profile 11a similar to that of portion 15c of elastomeric member 15. Concave portion 11a terminates in a cusp 13 near the axially inner end of segment 11.
- Cusp 13 is engageable with the annular bead. Since there is an annular gap between the inner diameter of the socket end and the outer diameter of the spigot end, the metal segment is moveable relative to the bead. Such movement occurs by deflection of the metal segment with the cusp in engagement with and moving around the bead.
- Each segment 11 includes a heel portion l ib that is of similar shape to the shape of heel portion 15b of elastomeric member 15.
- the known Tyton anchor gasket 10 can accommodate some variations in the annular gap as outlined above.
- Segment 11 moves in the direction of arrow A in Figure 1 on insertion of the spigot into the socket. This causes the segment to seat more fully onto the bead and socket heel groove and thereby present a low profile.
- segment 11 moves in the direction of arrow B in Figure 1 to present a higher profile and thus perform its sealing and anchoring functions.
- Tyton anchor gasket Although the known Tyton anchor gasket has been successful, it nonetheless suffers some disadvantages. Principal among these is the tendency for the Tyton anchor segments to over-stress the spigot end when the fluid pressure in the pipe increases.
- the Tyton anchor has a limited pressure thrust capability. At small pipe diameters the pressure ratings are more than adequate to accommodate the working pressure but as the diameter increases the pressure rating decreases. At the pipe diameter known as 'DN400' the working pressure limit is only 10 bar. This is because the number of teeth in the metal segments can only increase in proportion to the pipe diameter whereas the pressure thrust increases in proportion to the square of the pipe diameter.
- EP-A-0596394 discloses a segment having a rear tooth that prevents segment rotation by engaging the upstanding wall 18 of the socket heel groove 17 of the socket end 14.
- FIG. 2 This design of segment is shown in Figure 2, in which the heel portion l ib of the metal segment terminates in a sharp tooth 22 that points towards the upstanding wall 18. Engagement of tooth 22 with the upstanding wall 18 prevents rotation of the segment beyond a predetermined point. However it is believed that once such engagement of the tooth 22 occurs the segment cannot further adjust its position if the spigot 16 deflects under pressure, e.g. due to ground movement after installation of the pipes underground.
- GB-A-2018924 discloses a segment design, similar to that of EP-A- 0596394, in which the heel portion of the segment is radiused to prevent the jamming of the segment that may arise in the EP-A-0596394 arrangement. However it is clear that the heel portion of the segment in GB-A-2018924 only engages the socket heel groove when there is a maximum annular gap between the spigot and socket ends.
- DE-A-2606643 discloses an arrangement that attempts to reduce the radial force acting between the segments and the pipe members. However, this design seems to suffer from the same disadvantage as the arrangement of GB-A-2018924 in that prevention of rotation apparently only occurs at a maximum annular gap.
- DE-A-2606643 segment only seems to function over a limited range of annular gaps. This is because the engaging parts of the metal segment and the heel groove are defined by perpendicular surfaces in each case, thereby limiting the possible range of effective movements.
- a gasket that functions both to seal a pipe joint and to prevent axial separation of the joint parts; and that exerts a reduced force on the spigot end at least for large annular gaps, while simultaneously permitting adjustment of the position of the segments over a large range of annular gaps.
- a gasket as defined in Claim 1.
- a low cusp height as defined in Claim 1 ensures that when the gasket is designed as a Tyton anchor gasket (in which manufacturing tolerances are small) the heel portion of the metal segment engages the upstanding wall of the socket heel groove for all annular gaps greater than or equal to the mean.
- the gasket of the invention can equally well be employed in anchors other than the Tyton type, and which may be associated with greater manufacturing tolerances. In such applications the heel may engage the wall, e.g. when the annular gap is at or close to its minimum. In other words the cusp height is low enough to allow the segment to deflect under the socket bead, but large enough to ensure positive engagement of the spigot before and after such deflection.
- the said distance, between the apex of the cusp and the most recessed part of the adjacent recess, is sufficiently small as to permit the entire segment to move, in use of the gasket, between the annular bead and the spigot end. This allows effective minimisation of the radial force.
- the said distance, between the apex of the cusp and the most recessed part of the adjacent recess, is sufficiently large as to ensure engagement between the segment and the bead when the segment is supported by the spigot end.
- the segment may remain in contact with the bead throughout any movement.
- the heel of the segment includes a portion shaped to permit relative movement between the heel and the socket heel groove while the heel engages the said wall of the socket heel groove.
- the shaped portion is convexly radiused and is engageable with the said wall.
- the distance between the apex of the cusp and the extremity of the heel remote from the cusp is such as to permit deflection of the segment towards the said wall of the socket heel groove until the cusp is at or near the tip of the socket bead.
- the heel of the segment includes a portion shaped to permit the heel to engage the socket heel groove at a level radially inward of the level of the tip of the socket bead. This has also been found to reduce the radial force.
- the elastomeric member is of a single, uniform hardness.
- the metal segments are effective at preventing the gasket from becoming dislodged from the socket bead on insertion of the spigot.
- the metal segments are also effective at preventing the gasket extruding between the socket mouth and the spigot.
- the invention also resides in a metal segment for a gasket as defined herein.
- Figure 1 is a cross sectional view of a conventional, prior art Tyton anchor gasket
- Figure 2 is a cross sectional view, showing the metal segment of EP-A- 0596394 in position in a socket heel groove but omitting the elastomeric member;
- Figure 3 is a cross sectional view of a gasket according to the invention.
- Figures 4A - 4C show the position of a metal segment of the gasket of Figure 3 when in use when there is respectively a minimum annular gap, a mean annular gap and a maximum annular gap between a chosen spigot and socket end;
- Figures 5A - 5C show views, similar to Figures 4, for an alternative embodiment of the segment.
- Figure 6 is a cross-sectional view of a further embodiment of the invention.
- annular gasket 10 for use in sealing and securing together two pipes respectively having a spigot end insertable into a socket end.
- the gasket 10 includes an annular elastomeric member 15.
- Elastomeric member 15 includes a substantially circular cross section sealing portion 15a that blends into a heel portion 15b whose cross section is a chamfered rectangle as shown.
- transition zone 15c of the member 15 is concavely curved to a profile corresponding to that of the bead 19 ( Figures 4 & 5) of the socket end 14 into which the gasket 10 is insertable.
- the gasket 10 also includes a series of metal segments 11 secured within and distributed round the annular member 15.
- Each segment 11 has a plurality of teeth 12a, 12b, 12c that extend towards the centre axis of the socket end, for engagement with the spigot 16.
- the teeth 12a, 12b, 12c protrude through the elastomeric member 15.
- Each metal segment 11 includes a heel 20 that is remote from the teeth 12a, 12b, 12c. Heel 20 is engageable with the wall 18 of the socket heel groove 17.
- segment 11 is formed as a concave portion 11a that terminates at its forward end in a cusp 13.
- Cusp 13 defines the transition in the segment 11 from a curved profile to a substantially flat profile in the region lie visible in Figure 3.
- the bead 19 acts as a fulcrum about which cusp 13 pivots when the gasket 10 is in use.
- the distance h between the apex of cusp 13 and the most recessed part of concave portion 11a, measured in the direction perpendicular to a tangent to the said most recessed part, is sufficiently small that the heel 20 engages the wall 18 for all degrees of tilt of the segment 11 greater than or equal to the tilt corresponding to the mean annular gap between the spigot and socket ends that the gasket 10 is in use to seal.
- the distance h and other dimensions of the metal segment may be chosen so that the heel 20 engages the wall 18 for degrees of tilt corresponding to less than the mean annular gap.
- Figure 4 shows the action of segment 11 of Figure 3 when the gasket 10 is in use to seal and retain a pipe joint.
- Figure 4A shows the segment 11 in use when the annular gap G is less than the mean annular gap between the spigot 16 and socket 14. In this situation the flange 23 of the socket end is in contact with the spigot 16, signifying that the socket 14 and spigot 16 are as close together as possible.
- the circular section part (known as the "bulb") of the elastomeric member 15 is received in the gallery 24 that lies axially inwardly of the bead 19. In this position the elastomeric member seals the joint.
- annular gap G has increased to the mean, primarily as a result of manufacturing tolerances. The increase can also arise by virtue of e.g. deflection of the pipes under a load caused by ground movement.
- the cusp height is sufficiently low as to permit the segment 11 to deflect under the bead 19.
- the cusp height h is on the other hand sufficiently high that the segment positively engages the spigot 16.
- the heel 20 engages the wall 18. This is preferably achieved through judicious choice of the dimensions of the segment and socket portions.
- the correct dimensions may be determined by the Tyton gasket (i.e. without inserts).
- Dimensions of the inserts can be determined by striking a radius of length 'r' from the cusp 13 of the insert when the dimension 'r' of the socket is on the mean. In contrast, in Figure 5 (described below) the radius has been struck from a point below the cusp.
- the heel 20 is radiused over a part of its outer surface.
- the heel 20 includes a radiused portion that terminates in a substantially planar portion as shown. This permits the heel to move relative to the wall 18 even after the heel 20 has engaged the wall.
- Figure 4C shows that with a further increase in the gap G the segment deflects further around the bead 19, until the cusp 13 is at or near the tip of the bead 19.
- the dimension r may be similarly determined in all embodiments of the invention, if desired.
- Figure 4C demonstrates that the heel 20 is able to continue to move relative to the wall 18 after these components have engaged one another.
- the segment 11 can accommodate further increases in annular gap arising from deflection or eccentricity of the spigot relative to the socket.
- Tooth 12a is out of engagement with the spigot.
- the tooth 12c is positioned as far forward as possible in order to maximise the length of lever arm L indicated in Figure 4C. This also reduces the radial force.
- the cusp angle A that defines the cusp height h, is in preferred embodiments 6°.
- the bulb of the elastomeric member has a diameter D.
- the Figures 5 show a second embodiment of segment for use in a gasket according to the invention.
- the Figure 5 segment is similar to the Figure 4 segment, except that the heel 20 is radiused over the whole of its end surface that may contact the wall 18.
- the curved heel surface extends to a lower point in this embodiment, to ensure that there is a sufficient curved surface for all possible engagement angles with the wall of the socket heel groove.
- the radius 'r' is struck from a point slightly below the cusp 13, to ensure that the heel engages the wall at a level below the cusp.
- FIG. 6 there is shown another embodiment of the invention, including two further, optional feamres that may be included separately or together in the same segment 11.
- FIG 6 the cusp 13 of Figures 3 to 5 is replaced by a flat 13a.
- Flat 13a makes a tangential (point) contact with the bead of the socket heel groove, that is similar to the point contact of the cusp in Figures 3 to 5.
- the flat 13a provides such point contact (i.e. it sits "on top” of the bead) over a wide range of annular gaps.
- the flat 13a is useful in e.g. non-Tyton anchors, that suffer greater tolerances than the Tyton design.
- Figure 6 also shows a recess 11a' that is of generally trapezoidal profile, instead of the arcuate profile of Figures 3-5.
- Other recess shapes/profiles are also possible.
- the elastomeric member can be manufactured entirely from a single hardness material. Thus there is no need for a high stiffness portion as is sometimes called for in the prior art.
Abstract
Description
Claims
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB9918806 | 1999-08-11 | ||
GB9918806A GB2353076B (en) | 1999-08-11 | 1999-08-11 | A gasket for securing pipes or pipe components |
PCT/GB2000/002508 WO2001013023A1 (en) | 1999-08-11 | 2000-06-30 | A gasket for securing pipes or pipe components |
Publications (1)
Publication Number | Publication Date |
---|---|
EP1255946A1 true EP1255946A1 (en) | 2002-11-13 |
Family
ID=10858884
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP00940662A Withdrawn EP1255946A1 (en) | 1999-08-11 | 2000-06-30 | A gasket for securing pipes or pipe components |
Country Status (7)
Country | Link |
---|---|
EP (1) | EP1255946A1 (en) |
AU (1) | AU5557100A (en) |
CO (1) | CO5280160A1 (en) |
EG (1) | EG22184A (en) |
GB (1) | GB2353076B (en) |
HK (2) | HK1030977A1 (en) |
WO (1) | WO2001013023A1 (en) |
Families Citing this family (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7108289B1 (en) | 2000-06-08 | 2006-09-19 | United States Pipe And Foundry Company, Llc | Restraining gasket for mechanical joints of pipes |
US7104573B2 (en) | 2000-06-08 | 2006-09-12 | United States Pipe And Foundy Company, Llc | Energized restraining gasket for mechanical joints of pipes |
US7137653B2 (en) | 2003-09-25 | 2006-11-21 | United States Pipe And Foundry Company, Llc | Centroidally twistable compression ring for pipe joints |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
DE2606643B2 (en) * | 1976-02-19 | 1978-12-14 | Buderus Ag, 6300 Lahn-Wetzlar | Shear-proof push-in socket pipe connection |
DE2809307C2 (en) * | 1978-03-03 | 1983-09-15 | Georg 8000 München Seiler | Push-in socket connection of pipes and pipe elements |
DE3405988A1 (en) * | 1984-02-20 | 1985-08-22 | Georg 8000 München Seiler | Tension and shear securing device, which seals and is at the same time electrically isolating, on pipe connections |
US5464228A (en) * | 1992-11-04 | 1995-11-07 | United States Pipe And Foundry Company | Restraining element for pressure pipe joints |
GB2272264B (en) * | 1992-11-04 | 1995-12-06 | Victaulic Plc | Pipe joints and gaskets therefor |
-
1999
- 1999-08-11 GB GB9918806A patent/GB2353076B/en not_active Expired - Fee Related
-
2000
- 2000-06-30 EP EP00940662A patent/EP1255946A1/en not_active Withdrawn
- 2000-06-30 WO PCT/GB2000/002508 patent/WO2001013023A1/en not_active Application Discontinuation
- 2000-06-30 AU AU55571/00A patent/AU5557100A/en not_active Abandoned
- 2000-08-08 EG EG20001032A patent/EG22184A/en active
- 2000-08-09 CO CO00059535A patent/CO5280160A1/en not_active Application Discontinuation
-
2001
- 2001-03-19 HK HK01101955A patent/HK1030977A1/en not_active IP Right Cessation
-
2002
- 2002-12-04 HK HK02108810.9A patent/HK1047614A1/en unknown
Non-Patent Citations (1)
Title |
---|
See references of WO0113023A1 * |
Also Published As
Publication number | Publication date |
---|---|
HK1030977A1 (en) | 2001-05-25 |
CO5280160A1 (en) | 2003-05-30 |
HK1047614A1 (en) | 2003-02-28 |
WO2001013023A1 (en) | 2001-02-22 |
EG22184A (en) | 2002-10-31 |
GB2353076B (en) | 2004-03-17 |
AU5557100A (en) | 2001-03-13 |
GB2353076A (en) | 2001-02-14 |
GB9918806D0 (en) | 1999-10-13 |
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