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EP-4251892-B1 - PIPE JOINT WITH SEALING GASKET FOR DUCTILE IRON PIPE

EP4251892B1EP 4251892 B1EP4251892 B1EP 4251892B1EP-4251892-B1

Inventors

  • PACHECO, Rodney
  • QUESADA, GUIDO
  • ROJAS, BERNAL
  • CORBETT, JR., Bradford, G.

Dates

Publication Date
20260506
Application Date
20211119

Claims (6)

  1. A pipe joint comprising a female ductile iron pipe end (17), a sealing gasket (11) and a mating male pipe end (19), wherein the sealing gasket (11) is installed within a raceway (13) provided within a mouth region (15) of the female ductile iron pipe end (17), the mouth region (15) located adjacent an end opening of a belled end of the female ductile iron pipe end (17), the sealing gasket (11) being capable of sealing the female ductile iron pipe end (17) to the mating male pipe end (19), the mating male pipe end (19) having an interior surface (21) and an exterior surface (23) the sealing gasket (11) having an annular gasket body (31) made of a resilient elastomeric material, the annular gasket body (31) having an inner circumferential region (33) and an outer circumferential region (35) which form a pair of lobes (53, 55), as viewed in cross-section, the lobes being partly separated by an insertion force reduction notch (37), the gasket body (31) also having a circumferential groove (39) for receiving a mating circumferential reinforcement band (41), the annular gasket body (31) being installed within the raceway (13) provided in the mouth region (15) of the female ductile iron pipe end (17) so that the outer circumferential region (35) forms a seal with the mouth region (15) and the inner circumferential region forms a sealing surface for the exterior surface (23) of the mating male pipe end (19): the sealing gasket (11) comprising the circumferential reinforcement band (41), the circumferential reinforcement band (41) being received within the circumferential groove (39) of the gasket body (31), wherein the circumferential reinforcement band (41) has a continuous circumferential body which is made of a synthetic polymer which has a greater hardness than the elastomeric material of the remainder of the gasket body (31); wherein the circumferential reinforcement band (41) has a plurality of spaced rigid tabs (43, 45) which extend outwardly from the circumferential body (51) of the band at a predetermined spacing which extends around the circumference of the body of the band, the tabs (43, 45) being received after installation within a portion of the raceway (13) formed in the belled end, each of the tabs (43, 45) having a bottom surface (45) which extends to an inner vertical sidewall (49) and an oppositely arranged outer vertical sidewall (47); and wherein the raceway (13) provided within the mouth region (15) located adjacent the end opening of the belled end of the female ductile iron pipe end (17) has two regions of increased diameter (25, 27) separated by a region of lesser diameter (29), giving the raceway (13) a dual pocket appearance when viewed in cross-section, the outer circumferential region (35) of the gasket body (13) fitting in one pocket and the tabs (43, 45) of the circumferential reinforcement band (41) are received in the other respective pocket with the gasket (11) assembled in the raceway (13).
  2. The pipe joint of Claim 1, wherein the resilient elastomer used to form the annular gasket body (31) is an EPDM rubber.
  3. The pipe joint of Claim 1, wherein the circumferential reinforcement band is formed of polypropylene.
  4. The pipe joint of Claim 1, wherein the body of the circumferential reinforcement band (41) has a rearwardly extending body portion (51) which is received and bonded within the circumferential groove (39) of the gasket body (31), the increased height of the rearwardly extending body portion (51) serving to help prevent extrusion of the sealing gasket (11) under pressure.
  5. The pipe joint of Claim 1, wherein the annular gasket body (31) is chemically bonded to the circumferential reinforcement band (41).
  6. The pipe joint of Claim 1, wherein the circumferential reinforcement band (41) is mechanically interlocked with the annular gasket body (31) with no chemical bonding.

Description

1. Field of the Invention: The present invention relates generally to the field of pipe connections such as those used in the municipal water and sewer pipeline industries. More particularly, this invention relates to a sealing gasket for use in joining sections of ductile iron pipe used in such industries and to a method for manufacturing such a gasket. 2. Background of the Invention and Description of the Prior Art: Pipes are commonly used for the conveyance of fluids under pressure, as in city water lines. They may also be used as free-flowing conduits running partly full, as in drains and sewers. Pipes for conveying water in appreciable quantities have been made of steel, cast iron, concrete, vitrified clay, and most recently, plastic including the various polyolefins and PVC. In many applications where lengths of pipe are joined in telescoping relationship, the spigot end of one pipe is inserted into the socket end of the engaging pipe at a pipe joint or "coupling." The socket end has an opening large enough to receive the spigot end of the mating pipe. A gasket is typically present within the socket end of the pipe which is intended to prevent leakage of fluid from the joint by forming a seal between the two pipe sections. Piping systems of the above type also typically include "fittings" as that term is defined in the industry. A fitting is a term which will be familiar to those in the relevant industries and includes a piece, often curved or at an angle, as a coupling, an elbow, a valve, a Tee, etc. used for connecting lengths of pipe or as an accessory to a pipe in a piping system for conveying fluids. One important consideration in piping systems of the above type, whether in a straight run of pipe or at a fitting, is to provide adequate sealing at the pipe joints or couplings. In the case of ductile iron pipe installations, the sealing gasket must often perform in extreme circumstances in maintaining a proper seal at the pipe joints or couplings. Whereas the allowable clearance or raceway present between a female belled plastic pipe end and a mating male plastic spigot pipe end might be on the order of 5.5 mm, the same clearance or raceway in a ductile iron pipe system might be appreciably greater. This is due, at least in part, to the difference in manufacturing tolerances and techniques utilized in manufacturing the two types of pipe. Because of the difference in dimensional tolerances which are present in ductile iron pipe systems, it would be desirable to provide some type of mechanism to prevent the gasket from blowing out of the groove provided in the belled pipe end during use. The mechanism used to prevent blow-outs of this type should also be such that it does not interfere with bending of the gasket during initial insertion of the gasket into the sealing groove provided in the belled pipe end. One gasket used for many years in the ductile pipe industry is the so-called Tyton® gasket produced by U.S. Pipe and Foundry Company of Birmingham, Alabama, USA. This gasket is advertised as being used in U.S. Pipe's Tyton® Joint and HP LOK® Joint Ductile Iron Pipe and Fittings. It is a circular rubber gasket which has a modified bulb shape in cross section. All conventional Tyton® gaskets are made from vulcanized synthetic rubber with a soft rubber bulb and a harder heel joined in a strong, vulcanized band. The standard rubber compound is SBR, i.e., styrene butadiene rubber. This material has a maximum service temperature rating of 150 °F and is commonly used as a gasket material for drinking water, sanitary sewer applications, and the like. While the Tyton® gasket has been successfully used for many years, it would be desirable to provide a gasket for ductile iron pressure pipes which would be less expensive to produce by generating a new slim seal shape which reduces the volume of rubber required as much as possible. A need exists, accordingly, for an improved sealing gasket for ductile iron pipelines which includes special features which insure that it will not be blown out of its associated retaining groove under high pressure situations. A need also exists for such an improved sealing gasket for ductile iron pipelines which is cost-effective, easy to manufacture and easy to use in the field and which is dependable in operation. Document US 4,818,209 discloses a mould and sealing ring for constituting a mould element in forming a socket end of a thermoplastic material pipe and for sealing the space of a pipe joint between the socket end and the spigot end of a pipe introduced into the socket end. The mould and sealing ring comprises a sealing portion consisting of rubber and a reinforcing portion consisting of relatively rigid plastic material and connected with each other at a connection surface which is of substantially V-shaped cross-section provided that the reinforcing portion extends into the sealing portion between portions projecting radially outside and inside of the sealing portion.