| 摘要 |
The packing yarn is composed of layered ribbons with alternating layers of at least one flexible graphite and a reinforcement layer. The ribbons (9,9',9) of layered materials (10) have a width of not more than 5 mm. The flexible graphite (1,1') has a thickness of not more than 1 mm and a bulk density of 0.7-1.8 g/cm<3>. Other layers (3,3') are of metal foil with a thickness of 5-50 mu m and a tensile strength of at least 250 MPa. The ribbons (9,9',9) have additionally at least one layer of plastics film. The ribbons are given lateral ripples, across their longitudinal axis. The packing yarn (15,17) is composed of at least two ribbons (9,9',9), where at least one is twisted. The ribbons (9,9'9) can be of layers (10) with a width of not more than 3 mm or 2 mm, containing a graphite film (1) with a thickness of not more than 0.5 mm or 0.35 mm. The reinforcement metal foil (3,3') has a thickness of 10-20 mu m. At least one of the outer surfaces of the ribbons (9,9',9) is covered by a bonded plastics film layer. The flexible graphite film (1) has a graphite content or at least 96 wt% or 99 wt%. The metal foil (3,3') is bonded to the graphite film (1) with or without an adhesive, and they can be welded together at a high temp. such as 240-270 degrees C or 350-380 degrees C using a pressure of at least 0.1 MPa, using a non-adhesive bonding process as described in EP 0 616 884 B1. The packing yarn is composed of at least two twisted ribbons (9,9',9) of at least two different material layers, using at least a layer of flexible graphite film (1,1') and at least one metal foil (3,3'), and at least one layer of a flexible graphite film and a plastics film layer with a tensile strength of at least 25 MPa and an elasticity module of at least 0.4 GPa. The packing yarn of ribbons (9,9',9), twisted together, contains not more than 12 layers with up to four overlaid layers of flexible graphite film (1,1'), each bonded to a reinforcement metal foil layer (3,3') and a plastics film layer. An Independent claim is included for a production process, where a flexible graphite film (1) is bonded to a reinforcement metal foil (3), and the bonded layers (10) are cut into ribbons (9,9',9). At least two ribbons (9) are twisted together in a textile yarn twisting process to give a twisted packing yarn (15), which is shaped (16) into the required cross section for the final packing yarn (17). Preferred Features: The operation is a continuous process to bond the graphite (1) and metal (3) layers together in strips. The packing yarn (15) is shaped (16) into a calibrated round, oval, elliptical or rectangular cross section. In addition, at least one of the uncovered surfaces of the flexible graphite film can be covered by a plastics film layer, bonded in place with or without an adhesive. At least three of the ribbons (9,9',9) are twisted together to form a yarn (15), or two ribbons are twisted together. At least one of the bonded ribbons (9) from the bonded web (10) can be twisted into a yarn. |
