Process for joining overlapping thermoplastic membrane components

A method of joining overlapping thermoplastic geomembrane components to form a geomembrane liner or a geomembrane cap, the method comprising:

• providing a first geomembrane component having a first edge portion comprising a thermoplastic material;
• providing a second geomembrane component having a second edge portion comprising a thermoplastic material;
• providing a pair of first and second forms having complementary molding surfaces, with the complementary molding surface of the first form being defined by an electrically conductive metal susceptor;
• positioning the first and second edge portions in overlapping relationship between the first and second forms adjacent the metal susceptor such that opposed surfaces of the first and second edge portions contact each other to establish a faying interface therebetween at a weld site;
• positioning an electrically conductive coil adjacent the metal susceptor and on the opposite side of the faying interface as the metal susceptor such that the faying interface is positioned between the metal susceptor and the electrically conductive coil;
• heating the metal susceptor by passing an alternating current through the electrically conductive coil to generate an alternating magnetic field that acts on the metal susceptor and induces heating within the metal susceptor such that heat is transferred by thermal conduction from the metal susceptor to the first and second edge portions of the first and second geomembrane components to locally melt and coalesce at least a portion of the thermoplastic material of the first edge portion and at least a portion of the thermoplastic material of the second edge portion and form a zone of coalesced thermoplastic material along the faying interface at the weld site;
• cooling the zone of coalesced thermoplastic material to form a solid weld joint of resolidified thermoplastic material that fusion welds the first and second edge portions of the first and second geomembrane components together at the weld site to thereby form a geomembrane liner or a geomembrane cap.