Process for producing gripping elements for sealing and restraint systems for fluid pipelines and pipe joints produced thereby

A method for manufacturing a hardened gripping element for a sealing and restraint system used for forming a pipe joint in a water or sewer fluid pipeline of the type used in the waterworks industry, the method comprising the steps of:

• providing a starting material comprised of an interfacially modified particulate and polymer composite material, the starting material comprising a metal particulate phase and a polymer phase;
• creating a three dimensional printed metallic mold of the gripping element that is to be manufactured;
• forming a green metal composite article by injection molding the starting material mix in an injection molding machine into the three dimensional metallic mold to thereby form a metal polymer composite article having at least one gripping surface having a plurality of gripping teeth;
• in a single step, thermally debinding and sintering the green metal composite article to produce a near finished hardened gripping element;
• finish machining the hardened gripping element to form a finished hardened gripping element;
• and
• wherein the finished hardened gripping element is further characterized as having a linear shrinkage of less than 10%.

A method forming a sealed and restrained pipe joint between two sections of plastic pipe in a water or sewer fluid pipeline of the type used in the waterworks industry, the method comprising the steps of:

• providing a starting material comprised of an interfacially modified particulate and polymer composite material, the starting material comprising a metal particulate phase and a polymer phase;
• creating a three dimensional printed metallic mold of the gripping element that is to be manufactured;
• forming a green metal composite article by injection molding the starting material mix in an injection molding machine into the three dimensional metallic mold to thereby form a metal polymer composite article having at least one gripping surface having a plurality of gripping teeth;
• thermally debinding and sintering the green metal composite article to produce a near finished hardened gripping element;
• if necessary, finish machining the near finished gripping element to produce a finished element;
• incorporating the finished metal composite article into a sealing and restraint system where the metal composite article is paired with a sealing gasket to thereby form a sealing and restraint system;
• installing the sealing and restraint system into a mouth region of a section of belled plastic pipe;
• installing a male pipe end into the mouth region of the section of belled plastic pipe to thereby form a sealed and restrained pipe joint;
• and
• wherein the finished hardened gripping element which is used in the sealing and restraint system is further characterized as having a linear shrinkage of less than 10%.