GORE™ GR Sheet Gasketing Case Histories

Application-Chemical Processor, Sulfuric Acid

Summary
Produced at high temperatures, this extremely corrosive acid-approximately 1 on the pH scale-presents a serious challenge to personnel and materials. A large producer and consumer of this aggressive acid ran at temperatures as high as 220°C. An absorption tower was used to release heat, which was then used to generate steam for energy. Filled PTFE was chosen for the tower for its chemical resistance. Unfortunately, the service life offered by this material was limited because of creep and blow-out. In that the plant closed down for maintenance every two years, they wanted a gasket material that would ensure no unplanned downtime. GORE-TEX GR sheet gasketing was installed during the next planned shutdown.

Results
During the following two years, and until the next planned maintenance outage, none of the gaskets failed. When they opened the joints, engineers were surprised at how flexible the gaskets remained. Their previous gaskets generated problems because they hardened very quickly and lost sealability. The absorber was then refitted with new GORE™ gaskets, which the plant engineers were confident would last two years until the next planned outage.

Application-Detergent Manufacturer, Shell & Tube Heat Exchanger

Summary
A frustrating challenge for a detergent manufacturer was to deliver heated water into the process up to 100 times per day with incremental cool-down periods between production batches.  Temperatures would quickly spike from ambient (outdoor) water temperatures to 150°F at 70 psi.  Particularly during the winter months, this meant a significant & repeated temperature fluctuation that a shell & tube heat exchanger had to endure.  With steam on the shell side and incoming water on the tube side, the flange dynamics and resulting gasket loads were constantly changing.  In fact, during the winter, the plant averaged only 1 week gasket life before leakage failure.  During the summer months (with reduced temperature gradient), operating terms up to 6-months could on occasion be realized.  The plant took initiative to maximize initial bolting loads, but ultimately leakage occurred due to gasket creep, or sometimes gasket fracture when too much load was applied.  The plant tried several material types to include graphite and premium filled PTFE gaskets.  The results were the same.  After consulting Gore, the manufacturer decided to try GORE™ GR sheet gasketing in a few of the units.

Results
After gaining confidence in the early results, the manufacturer switched the remaining heat exchangers over to GORE™ GR sheet gasketing since May of 2005.  Despite it’s soft & conformable nature, the Gore gasket delivers the highest level of creep resistance among PTFE gaskets.  And, with extremely high fracture resistance, it is also difficult to over-compress the Gore gasket.  Now, the detergent manufacturer has for the first time experienced trouble-free flange operations in the shell & tube heat exchangers through both the summer and winter seasons.  Thrilled, the plant personnel have plans to use the Gore gasket in other areas of the plant as a result.