Teadit Graflex Gasket Graphite

FLEXIBLE GRAPHITE - GRAFLEX ® The Flexible Graphite produced from natural graphite has a Carbon content between 90% to 99.9% . Graphite flakes are treated with acid, neutralized with water and dried. The flakes are then subjected to high temperature, and the water, after vaporizing, “ explodes” the flakes, which increase 200 times or more than its original volume. Those expanded flakes are calendered without any additive or binder, producing sheets of flexible material. Flexible Graphite shows low creep defined as a continuous plastic deformation in a material subject to pressure. Therefore, there is a small loss of bolt load, which reduces the need for retightening of bolts. Due to its characteristics, Flexible Graphite is one of the most reliable sealing materials. If offers excellent resistance to acids, alkaline solutions and organic composites. However it is not recommended for use in oxidant service in temperatures above 840 o F ( 450 o C) , the heated Carbon reacts with the Oxygen forming Carbon Dioxide ( CO 2 ) . The result of such a reaction is the reduction of the gasket mass and, consequently of bolt load. Temperature limits: -400 o F ( -240 o C) to 5400 o F ( 3000 o C) , in reducing or neutral service without contact with Oxygen. For oxidant service the upper limit is 840 o F ( 450 o C) . The chemical compatibility and temperature limits for several chemical and organic compounds are shown on Annex 3.1 at the end of this Chapter. 5.1. GRAFLEX ® SHEETS Being a material with low mechanical strength Graflex Flexible Graphite sheets are supplied with an AISI 316 Stainless Steel or Polyester insert. Sheet dimensions are 1000 mm x 1000 m ( 39" x 39" ) and the standard thickness are 0.8 mm ( 1/ 32" ) , 1.6 mm ( 1/ 16" ) and 3.2 mm ( 1/ 8" ) . The different styles are shown on Table 3.2. It is necessary to verify the chemical and temperature compatibility of the insert when designing gaskets with Graflex sheets. The values for “ m” and “ y” and the PVRC Gasket Constants are shown on