Case Study: GYLON TUFF-RAIL® 3504 - Chemical Processing


Chemical Processing


Size: Variety of ID sizes ranging upwards of 11.50” OD
Temperature: Ambient (-40°F to 120°F)
Application: Rail tank car / acid fill hatch cover – 3 or 4 bolt
Media: Sulfuric Acid
Pressure: Typical is 25 psi or less


A North American sulfuric acid producer uses nonpressurized rail tank cars that load and unload through the top. There are no bottom outlet devices, only basic washout nozzles. The fill hatch assembly repair centers had field challenges and needed a more reliable and easier-to-maintain sealing solution.


The manufacturing and service centers are often located in cold climates, creating challenges for gasket installation, removal, and sealing. While a PTFE-encapsulated fluoroelastomer (B-type FKM) rubber gasket is chemical resistant, the low temperatures made the gaskets become brittle over time, as FKM is not rated for less than -40°F. The gaskets split, stuck to the hatch assembly, and were hard to remove. The flange needed frequent cleaning, which did not allow for reusability.


The hatch cover design is unique, with the gasket held in place by stretching the gasket ID over a raised area inside the nozzle and into a channel on the cover. The proprietary and patented GYLON TUFF-RAIL® technology meets these requirements. It is chemical and temperature-resistant while providing stress optimization through the raised sealing rib features. The molded gasket has a “dual ID” feature with tabs for easy installation and removal. It’s flexible enough to fit over the raised area and into the hatch cover channel, but rigid enough to snap in place and self-center.

The customer reported easy gasket installation and removal, plus the ability to reseal, even after the hatch cover was opened, loaded, and closed multiple times. The TUFFRAIL® 3504 Fill Hatch gasket technology was approved and added to the customer’s specification for the fleet.

Click here to learn more about GYLON TUFF-RAIL® 3504.