Gripping gasket
A novel gasket includes at least one gripping element embedded in an annular member for forming a seal between two tubulars. For tubulars having socket and spigot ends, the gripping element includes teeth for gripping an outer surface of the spigot end and a blunt tooth for contacting a front wall of the socket end. The blunt tooth rolls along the front wall during relative movement between the tubulars and can include a contacting face of a specialized geometry to adjust contact dynamics and/or roughened surfaces to increase the frictional contact between the blunt tooth and the front wall. The embedded element can also include at least four teeth arranged such that no more than two teeth normally grip the outer surface of the spigot end. One or more teeth can also include a transverse groove to enhance penetration into the outer surface of the spigot end.
1. A device for joining a first tubular having a socket end with a second tubular having a spigot end, the socket end having a retainer groove formed by a front wall, a radially outward surface, a retainer wall, and a circumferential compression rib that projects radially inward from a sealing wall, the device comprising:
(a) a resilient annular member having a sealing portion for forming a seal between the first tubular and the second tubular:
(b) at least one gripping element positioned in the resilient member, the gripping element having:
(i) a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end; and
(ii) a blunt tooth extending axially forward toward the socket end for contacting the front wall, the blunt tooth rolling along the front wall during relative movement between the first and second tubular.
2. The device of claim 1 wherein the blunt tooth includes one of (i) a convex face, and (ii) a concave face.
3. A device for joining a first tubular having a socket end with a second tubular having a spigot end, comprising:
(a) a resilient annular member having a sealing portion for forming a seal between the first tubular and the second tubular;
(b) at least one gripping element positioned in the resilient member, the gripping element having:
(i) a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end; and
(ii) a blunt tooth extending axially forward toward the socket end for contacting a front wall of the socket, the blunt tooth contacting and rolling along the front wall during relative movement between the first and second tubular, wherein the blunt tooth includes a roughened surface for increasing the frictional contact between the blunt tooth and the front wall.
4. The device of claim 3 wherein the roughened surface includes one of: (i) an irregular surface formed by grit blasting, (ii) chemical etches, (iii) spline protrusions, (iv) knurled protrusions, (v) impregnated grit, (vi) composite constructions, (vii) bonded elements, and (viii) coated elements.
5. The device of claim 3 wherein the plurality of teeth includes at least four teeth arranged such that no more than two teeth grip the outer surface of the spigot end when the spigot end is inserted into the socket end.
6. The device of claim 5 wherein at least three of the at least four teeth lie along a common arc.
7. The device of claim 3 wherein the gripping element includes a ridge extending radially outward from the gripping element, the ridge positioned to limit the movement of the blunt tooth along the front wall.
8. A method for joining a first tubular having a socket end with a second tubular having a spigot end, the socket end having a retainer groove formed by a front wall, a radially outward surface, a retainer wall, and a circumferential compression rib that projects radially inward from a sealing wall, the method comprising:
(a) forming a seal between the first tubular and the second tubular with at least a portion of a resilient annular member;
(b) positioning at least one gripping element in the resilient member, the gripping element having a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end, and a blunt tooth extending axially forward toward the socket end for contacting the front wall, the blunt tooth rolling along the front wall during relative movement between the first and second tubular.
9. The method of claim 8 further comprising arranging at least four teeth of the plurality of teeth such that no more than two teeth grip the outer surface of the spigot end when the spigot end is inserted into the socket end.
10. The method of claim 8 further comprising limiting the movement of the blunt tooth along the front wall using a ridge formed on the gripping element.
11. A method for joining a first tubular having a socket end with a second tubular having a spigot end, comprising:
(a) forming a seal between the first tubular and the second tubular with at least a portion of a resilient annular member;
(b) positioning at least one gripping element in the resilient member, the gripping element having a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end, and a blunt tooth extending axially forward toward the socket end for contacting a front wall of the socket end, the blunt tooth contacting and rolling along the front wall during relative movement between the first and second tubular; and
(c) roughening a surface of the blunt tooth to increase the frictional contact between the blunt tooth and the front wall.
12. A gasket for mating a first pipe having a socket end with a second pipe having a spigot end, the socket end having a retainer groove formed by a front wall, a radially outward surface, a retainer wall, and a circumferential compression rib that projects radially inward from a sealing wall, the device comprising:
(a) an annular body formed of a resilient material, the annular body having a central opening allowing the spigot end to enter therethrough;
(b) a plurality of inserts positioned in the annular body, each insert having:
(i) a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end; and
(ii) a blunt tooth extending axially forward toward the socket end for contacting the front wall, the blunt tooth rolling along the front wall during relative movement between the first and second tubular.
13. A gasket for mating a first pipe having a socket end with a second pipe having a spigot end, comprising:
(a) an annular body formed of a resilient material, the annular body having a central opening allowing the spigot end to enter therethrough;
(b) a plurality of inserts embedded in the annular body, each insert having:
(i) a plurality of teeth projecting radially inward toward the spigot end for gripping an outer surface of the spigot end; and
(ii) a blunt tooth extending axially forward toward the socket end for contacting a front wall of the socket, the blunt tooth rolling along the front wall during relative movement between the first and second tubular, wherein the blunt tooth includes a roughened surface for increasing the frictional contact between the blunt tooth and the front wall.
14. The gasket according to claim 13 wherein the roughened surface includes one of: (i) an irregular surface formed by grit blasting, (ii) chemical etches, (iii) spline protrusions, (iv) knurled protrusions, (v) impregnated grit, (vi) composite constructions, (vii) bonded elements, and (viii) coated elements.
15. The gasket according to claim 13 wherein the plurality of teeth includes at least four teeth arranged such that no more than two teeth grip the outer surface of the spigot end when the spigot end is inserted into the socket end.
16. The gasket according to claim 15 wherein the plurality of teeth includes at least four teeth and wherein at least three of the at least four teeth lie along a common arc.
17. The gasket according to claim 13 wherein the plurality of inserts each include a ridge extending radially outward therefrom, the ridge positioned to limit the movement of the blunt tooth along the front wall.
18. The gasket according to claim 17 wherein the plurality of inserts includes a resilient encapsulation for providing a cushion between the ridge and a surface of the socket end.