Snap in place gasket for sealing plastic pipelines and method of installation
A pipe sealing gasket is shown which is designed to be received within a groove provided within a belled, socket end of a plastic pipe. The groove in the plastic pipe is preformed during manufacture and the gasket is installed thereafter. The gasket nominal diameter exceeds the internal diameter of the belled pipe end. A special installation tool is used to pull the gasket from an initially deformed, elliptical shape to a normal cylindrical shape. The installation tool uses only one fluid cylinder for power and can be hand installed and operated.
1. A gasket for installation within a gasket receiving groove provided within the belled end of a plastic pipe section, the belled end having a mouth opening which is engageable with a spigot end of a mating plastic pipe section to form a pipe joint, the gasket comprising:
a ring-shaped gasket body formed of a flexible elastomeric material, the gasket body having an approximate midpoint thereon, the gasket body having a single relatively rigid ring located at an embedded location which circumscribes the gasket body, the relatively rigid ring being generally round in cross section, the relatively rigid ring having a cross sectional diameter which defines a locus of points on an inner surface thereof which is equal to or greater than the internal diameter of the remainder of the belled end of the pipe which joins the gasket receiving groove when the gasket is installed within the belied pipe end;
wherein the gasket body has an inner sealing surface which is provided with a series of serrations thereon, the inner sealing surface being joined to a leading face which joins a convex nose region which continues to form a primary sealing surface, the primary sealing surface comprising an evenly sloping outer face of the body and which forms a lip region thereof, the lip region being separated from a trailing face of the gasket body by means of a pair of convex regions which allow the lip region to converge inwardly as the mating male spigot end of the mating pipe section encounters the primary sealing surface of the gasket;
wherein the gasket body has a width to thickness ratio and wherein the ratio is greater than about 1.75:1.0;
wherein a vertical axis passes though the approximate midpoint of the gasket body and the relatively rigid ring is located within the gasket body in front of the vertical axis, as viewed along the longitudinal axis of the pipe, in a location adjacent the convex nose region; and
wherein the gasket body has a forward quarter, as viewed in cross-section, and wherein the relatively rigid ring is located in the forward quarter of the mass of the rubber of the gasket body.
2. The gasket of claim 1 , wherein the relatively rigid ring is formed of a material selected from a group consisting of hard plastics and composites, and steel.
3. The gasket of claim 1 , wherein the elastomeric material used to form the body of the gasket is formed of a material selected from the group consisting of natural rubbers, synthetic rubbers, styrene-butadiene rubber, ethylene propylene diene monomer rubber, acrylonitrile butadiene rubber, and nitrile rubber.