The Gasket of Choice for Critical Applications for Hydrofluoric Acid Service
Lamons® Defender HFTM gaskets are designed to provide an excellent seal on new and moderately corroded flange faces used in hydrofluoric (HF) acid service. With a patented two step Kammpro® metallic core, the Defender HF offers safe, high-integrity, primary and secondary sealing components that seal on the flange face to the bore. The customer piping classifications and process design specifications generally determine the materials of construction. Lamons has Monel® and other common core options available. Plus, in addition to the integral stepped Kammpro core, each gasket uses high purity APX2 flexible graphite and L-120 ePTFE covering layers. The Defender HF is also API 6FB certified (fire tested).
Design standards: Suitable for ASME B16.5 flanges: 1⁄2” to 24” (12 mm to 600 mm); DN 12 to 600; custom sizes for non-standard flanges
Gasket type: F
Gasket pressure range: Suitable for ASME B16.5 flanges; Class 150 to 2,500
Temperature range: -321°F to 500°F (-196°C to 260°C)
The Lamons Defender HF was tested against two major competitive gaskets by an independent, third-party company. The Defender HF had higher gasket stress on the ePTFE at the bore and better gasket stress on the graphite Kammpro outer section than the two competitor’s gaskets. The Defender HF achieved tighter sealing for a given load than either competitor. It also maintained that seal tightness as the load was reduced better than either competitor.
Dye penetration and stress profiling tests were performed on the Defender HF and two other competitive gaskets. The image below shows the amount of dye penetration to the three different gaskets loaded into a 4-inch, class 150 flange with B7 studs at 60 percent of yield stress. The adjacent image shows the actual stress profile on the sealing area of the gaskets…note the strong correlation between the two.
The gaskets were all tested via the EN 13555 industry standard test. The Defender HF was able to achieve seal tightness for Helium of 1×10-5mg/(m/s) with less load than either competitor. The Defender HF was also able to keep that seal tightness longer as the clamping load (gasket stress) was continually reduced per the test standard.